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PUBLICATIONS

IPCB ISI publications

 646 publications on ISI journals

1) Compatibilized polylactide/poly(pentamethylene furanoate) blends for fully bioderived packaging films with enhanced fracture toughness and UV- and O2-barrier properties

G.Fredi, D.Perin, C.Zardo, M.Rapisarda, P.Rizzarelli, M.Soccio, N.Lotti, A.Dorigato

Giant  18,  100267  - 2024

DOI: https://doi.org/10.1016/j.giant.2024.100267
Polylactide (PLA) is a promising biopolymer from renewable resources but its brittleness and poor gas barrier properties limit flexible packaging applications. Therefore, in this work PLA was blended with a biobased rubbery poly(pentamethylene furanoate) (PPeF), acting as a toughening agent, and a commercial epoxy-functionalized compatibilizer (i.e., Joncryl® ADR-4468) was added to improve the interfacial interaction. The effect of PPeF loading (1?30 wt %) on phase morphology, mechanical properties, oxygen permeability, and degradability in compost was characterized. All blends displayed a sea-island morphology with refined PPeF domains upon compatibilization. Incorporating PPeF induced major tensile ductility enhancements from 5 % strain at break for neat PLA up to 200 % for the blend with 30 wt % PPeF, accompanied by progressive stiffness and strength declines. Through the application of the essential work of fracture (EWF) approach on the prepared films, the specific essential work of fracture (we) was seen climbing from 6.2 to 40.0 kJ/m2 with rising PPeF content, confirming its effectiveness as a toughness enhancer. PPeF contributed to increase the UV- and gas barrier properties of PLA. For example, the oxygen permeability dropped by 37 % for the blend with 30 wt % PPeF. Moreover, compost burial tests also revealed 26 % weight loss of PPeF after 60 days, proving its biodegradability. Hence, finely dispersed PPeF domains induced synergistic property improvements, making PLA/PPeF blends a promising sustainable option for flexible and biodegradable packaging.

IPCB graphical abstract



2) pH-dependent catalytic activity of Au and Pd-based hybrid cryogels by investigating the acid/base nature of the polymeric phase

S.Scurti, G.Proietto Salanitri, T.Mecca, E.Rodríguez-Aguado, J.A.Cecilia, G.Curcuruto, S.Carroccio, D.Caretti, N.Dimitratos

Materials Today Chemistry   38,  102046  - 2024

DOI: https://doi.org/10.1016/j.mtchem.2024.102046
Over the last decade, cryogels have proven to be effective catalytic supports in various hybrid systems for the conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-NP). A critical determinant influencing the conversion of nitroaromatic compounds in the presence of sodium borohydride is the solution pH as suggested from Grzeschik's model. This study aims to investigate the catalytic mechanism and the role of pH in reactions mediated by hybrid catalysts. In particular, polymeric cryogels with different acid/base properties were prepared and used as supports for the in-situ preparation of Au and Pd nanocatalysts. Notably, catalytic tests showed the significant influence of the polymeric support's acidity on 4-NP reduction, with poly(acrylic acid)-based catalysts emerging as the most effective systems. To further probe the reaction mechanism, a series of catalytic tests were carried out, and the results demonstrated the effect of pH on the reaction process, allowing to propose a novel mechanism based on an extension of Grzeschik's model. Moreover, data emphasized the pivotal role of the polymer in the catalytic mechanism, showcasing its capacity to tune catalytic activity by altering the acid/base properties of the matrix substrates.

IPCB graphical abstract



3) Wood flour and hazelnut shells polylactide-based biocomposites for packaging applications: Characterization, photo-oxidation, and compost burial degradation

M.Baiamonte, M.Rapisarda, M.Ch.Mistretta, G.Impallomeni, F.P.La Mantia, P.Rizzarelli

Polymer Composites   - 2024

DOI: https://doi.org/10.1002/pc.28439
In this work, polylactide (PLA) was loaded with wood flour (WF) or hazelnut shells (HSs) (10% and 20% of fillers). The matrix and biocomposites were fully characterized from a mechanical and rheological point of view to test their processability and mechanical performance. Compost burial degradation test (30 days), with or without a prior photo-oxidation step, assessed their biodegradability after an outdoor application, and was monitored by weight loss (WL). The viscosity of the biocomposites was lower than that of the matrix and this unusual result can be attributed to a limited adhesion between the PLA and fillers. Both fillers increased the elastic modulus but decreased the tensile strength and elongation at break. As for the weathering, the degradation of PLA was mostly due to hydrolytic chain scission due to the presence of humidity. Resistance of PLA to UV irradiation improved in presence of both the two fillers. Their lignocellulosic nature was responsible for this behavior. Both fillers induced a high resistance and lower degradation in compost: WL percentages of virgin PLA was about 26%, biocomposites with 20% of WF or HS showed WL of about 10% and 14%, respectively. Photo-oxidation (36 h with condensation cycle) increased the compost degradation rate of both biocomposites and WL of PLA with 20% of WF or HS were about 15% and 21%, respectively, after 30 days.

IPCB graphical abstract



4) How the Crosslinker Amount Influences the Final Properties of Hydroxyethyl Methacrylate Cryogels

G.Proietto Salanitri, E.Luzzi, D.Caretti, T.Mecca, S.Carroccio, A.Scamporrino

Gels  10(3),  163  - 2024

DOI:  https://doi.org/10.3390/gels10030163
The investigation of the mechanical, thermal, and adsorption properties of hydroxyethyl methacrylate (HEMA) cryogels as a function of a reactant ratio is herein reported to better address materials for specific applications. To this aim, cryogels have been synthesized using different monomer/crosslinker (N,N'-methylene-bisacrylamide?MBAA) ratios. The study of SEM images made it possible to identify the trend in the material’s macroporosity. As would be expected, the average measured pore width decreased as the amount of MBAA increased while the number of pores grew. Swelling capacity ranges from 8.7 gW/ggel (grams of water per gram of gel) to 9.3 gW/ggel. These values are strictly connected with the pore’s size and distribution, revealing that the water uptake for the most crosslinked sample is inferior to other samples. The equilibrium-adsorption capacity (Qe) towards the methylene violet (MV) was also assessed, revealing no remarkable differences after 24 h of a batch test. As expected, thermogravimetric analysis (TGA) also showed no significant changes in stability that ranged from a maximum weight loss temperature (T Max) of 420 °C to 425 °C, which increased as a function of crosslinker content. Conversely, compression strength measurements showed a notable difference of about 50% in modulus (Ec), moving from the higher to the lower HEMA/MBAA ratio. These new comparative results indicate how slight variations in the reactant’s ratio can steadily improve the mechanical properties of the HEMA cryogel without affecting its adsorption efficiency. This can be helpful in the design of materials for water and energy purposes. Since swelling properties are needed in the case of biomedical applications, the HEMA/MBAA ratio should be tuned versus high values.

IPCB graphical abstract



5) Molecularly Mixed Composite Membranes for Gas Separation Based on Macrocycles Embedded in a Polyimide

D.Vuono, G.Clarizia, L.Ferreri, G.M.L.Consoli, D.Zampino, G.Scalzo, S.Petralia, P.Bernardo

Polymers  16(4),  460  - 2024

DOI: https://doi.org/10.3390/polym16040460
Polyimides are a polymer class that has been extensively investigated as a membrane material for gas separation owing to its interesting permselective properties in a wide range of operation temperatures and pressures. In order to improve their properties, the addition of different filler types is currently studied. p-tert-Butylcalix[n]arene macrocycles (PTBCs) with different cavity sizes (PTBC4, PTBC6, PTBC8) were used as fillers in a commercial thermoplastic polyimide, with a concentration in the range 1-9 wt%, to develop nanocomposite membranes for gas separation. The selected macrocycles are attractive organic compounds owing to their porous structure and affinity with organic polymers. The nanocomposite membranes were prepared in the form of films in which the polymeric matrix is a continuous phase incorporating the dispersed additives. The preparation was carried out according to a pre-mixing approach in a mutual solvent, and the solution casting was followed by a controlled solvent evaporation. The films were characterized by investigating their miscibility, morphology, thermal and spectral properties. The gas transport through these films was examined as a function of the temperature and also time. The results evidenced that the incorporation of the chosen nanoporous fillers can be exploited to enhance molecular transport, offering additional pathways and promoting rearrangements of the polymeric chains.


6) Green3: A green extraction of green additives for green plastics

V.Muccilli, A.E.Maccarronello, C.Rasoanandrasana, N.Cardullo, M.S.de Luna, M.G.G.Pittalà, P.M.Riccobene, S.Carroccio, A.Scamporrino

Heliyon  10(2),  e24469  - 2024

DOI: https://doi.org/10.1016/j.heliyon.2024.e24469
PLA/PBAT bioplastic is a commercial biodegradable plastic employed for packaging and several food and agriculture applications. In this regard, properties such as the antioxidant ability to extend food shelf life and light resistance, are of great interest in the production of packaging and mulching films, respectively. These features are obtained by developing blends with pure chemicals and/or natural products as additives. In the present work blend formulations of PLA/PBAT with a walnut shell extract rich in antioxidants were developed and evaluated for their properties in comparison with classic PLA/PBAT. Specifically, natural additives, and most importantly the production process were purposely selected to i) be green and cost-effective; ii) confer antioxidant properties; and iii) improve material performance To this aim, a walnut shell extract (EWS) with high antioxidant activity was obtained thanks to a novel green and cost-effective microwave-assisted extraction (MAE) procedure. A response surface methodology was utilized to explore how the total phenolic content (TPC) and antioxidant activity are influenced by varying aqueous ethanol concentration, extraction time, and microwave power. The highest predicted TPC and antioxidant activity were achieved when employing the ideal conditions for Microwave-Assisted Extraction (MAE): using a mixture of 30 % ethanol in water, an irradiation time of 120 s, and a microwave power of 670 W. The optimized EWS was characterized by HPLC-MS determining qualitative and quantitative data with the identification of flavonoids, fatty acids, and anacardic acids among the main components, responsible for antioxidant activity. The resulting EWS powder was melt-mixed at 140C° and 20 RPM with the bio-based PLA/PBAT bioplastic at two different concentrations (0.5 and 1.5 w/w) by forming film specimens. All EWS-based bioplastic films showed increased antioxidant features determined by the DPPH bleaching test, TEAC, and ORAC assays. The films keep the antioxidant capacity even after 7 days of UV-accelerated aging. Remarkably, adding 1.5 % EWS boosted the bioplastic UV light resistance, reducing the abatement of molecular masses by more than 60 % without affecting mechanical properties.

IPCB graphical abstract



7) Band Engineering versus Catalysis: Enhancing the Self-Propulsion of Light-Powered MXene-Derived Metal-TiO2 Micromotors To Degrade Polymer Chains

M.Urso, L.Bruno, S.Dattilo, S.Carroccio, S.Mirabella

ACS Applied Materials & Interfaces  16,  1293-1307  - 2023

DOI: https://doi.org/10.1021/acsami.3c13470
Light-powered micro- and nanomotors based on photocatalytic semiconductors convert light into mechanical energy, allowing self-propulsion and various functions. Despite recent progress, the ongoing quest to enhance their speed remains crucial, as it holds the potential for further accelerating mass transfer-limited chemical reactions and physical processes. This study focuses on multilayered MXene-derived metal-TiO2 micromotors with different metal materials to investigate the impact of electronic properties of the metal-semiconductor junction, such as energy band bending and built-in electric field, on self-propulsion. By asymmetrically depositing Au or Ag layers on thermally annealed Ti3C2Tx MXene microparticles using sputtering, Janus structures are formed with Schottky junctions at the metal?semiconductor interface. Under UV light irradiation, Au-TiO2 micromotors show higher self-propulsion velocities due to the stronger built-in electric field, enabling efficient photogenerated charge carrier separation within the semiconductor and higher hole accumulation beneath the Au layer. On the contrary, in 0.1 wt % H2O2, Ag-TiO2 micromotors reach higher velocities both in the presence and absence of UV light irradiation, owing to the superior catalytic properties of Ag in H2O2 decomposition. Due to the widespread use of plastics and polymers, and the consequent occurrence of nano/microplastics and polymeric waste in water, Au-TiO2 micromotors were applied in water remediation to break down polyethylene glycol (PEG) chains, which were used as a model for polymeric pollutants in water. These findings reveal the interplay between electronic properties and catalytic activity in metal-semiconductor junctions, offering insights into the future design of powerful light-driven micro- and nanomotors with promising implications for water treatment and photocatalysis applications.

IPCB graphical abstract



8) Editorial: Chemistry and the circular economy

P.Rizzarelli, A.Zuliani, N.Reddy

Frontiers in Chemistry  11  - 2023

DOI: https://doi.org/10.3389/fchem.2023.1350994
Chemistry stands as the cornerstone for life’s sustenance and progress on our planet, offering solutions to humanity’s challenges throughout history. In the modern era, Chemistry is an integral part of daily life, influencing science and technology. While its foundations lie in natural elements, synthetic chemistry advancements have excelled in cost, manufacturing ease, scalability, and consistency. Yet, concerns about health and environmental effects urge a reevaluation of the exploitation and applications of natural sources. Since 2000, global concerns like climate change and resource depletion have fueled extensive exploration for alternative solutions to using natural resources, especially amid environmental disasters, pandemics, and geopolitical struggles. One of the major approaches being considered to meet and overcome these challenges is by maximizing the use of natural resources and minimizing the generation of waste (Tseng et al., 2020). In this context, the concept of circular economy, where the waste and coproducts generated by one process are considered as inputs for another one and converted into value added products through clean and green approaches, is being aggressively pursued and adopted (Velenturf and Purnell, 2021).

Based on current statistics, the global agriculture market is expected to cross US$ 5 trillion by 2028. Consequently, the generation of byproducts and coproducts during agricultural production and processing is also set to increase steeply (Kircher, 2019; Díaz-Bonilla, 2023). Stems, leaves and husks generated during agricultural production and several byproducts, including proteins and carbohydrates, supplied as coproducts during agricultural processing are available in large quantities at low cost. These byproducts and coproducts have the essential constituents to be converted into monomers, polymers, compounds and further into any desired substance through specific chemical transformations, ranging from carbonyl reductions to carboxyl decarboxylations, hydroxyl oxidations, glycosylation, and transglycosylation (Li et al., 2014; Donner et al., 2021). For instance, corn-based biorefineries utilizing starch, corn husks, corn cobs, distillers dried grains and other coproducts have generated biofuels (ethanol, methane), biopolymers (polylactide), amino acids, animal feed and enzymes. Similarly, sugarcane based biorefineries have excelled in the production of biofuels, paper, fertilizers, animal feed, chemicals such as acetic acid, cosmetics and perfumes (Gerrior et al., 2022). Not only regular food crops but also non-food products such as poultry feathers have been considered for production of composite, plastics, biofuels, etc. Based on these approaches, it is evident that there is unlimited scope for extending the biorefinery and circular economy concepts to almost all agricultural byproducts and coproducts.

To achieve successful utilization and exploitation of renewable resources, the development of innovative and efficient conversion processes is essential. The purpose of the present Research Topic, "Chemistry and The Circular Economy", aligns with this goal. It displays the continuous progress and the potential of chemistry in addressing global challenges by bringing together research articles that explore advancements in energy storage, hydrogen production, polymer synthesis, and biochar utilization.

In the realm of energy storage, researchers have dedicated over 2 decades to refining biomass through rapid pyrolysis technology. However, challenges emerge as the primary product, biomass pyrolysis oil, grapples with low energy density and poor thermal stability. The intrigue deepens as exploration leads towards catalytic reforming as a transformative avenue, offering a potential solution for the subsequent utilization of bio-oil in hydrogen production. In a captivating mini review, Zhang focuses on the innovative technique of CO2 adsorption-enhanced catalytic reforming, presenting itself as a beacon of hope for efficient and sustainable hydrogen generation. The review briefly introduces recent progress in biomass catalytic reforming hydrogen production technology, covering mechanisms, catalyst selection, new processes, and technology developments. It also addresses current challenges in this field, providing potential ideas and directions for future development.

Shifting the focus to the captivating world of bio-derived polymers, the synthesis of poly-γ-glutamic acid (γ-PGA) comes into play. This water-soluble marvel holds promise as a game-changer in various applications. Its potential spans from the realms of drug delivery and cosmetics to bioremediation and wastewater treatment, weaving a tale of sustainability and versatility. Parati et al. explores the synthesis of γ-PGA from scalable macroalgal biomass assessing the influence of pre-treatment type, macroalgal species, and collection time on brown seaweed cultivated under controlled conditions in Scotland. Laminaria digitata, Saccharina latissima, and Alaria esculenta, three brown seaweed species native to the United Kingdom, are analyzed for their variation in carbon, antioxidant, protein, and ash content. The research evaluated the effect of different algal species on the yields and chemical composition of γ-PGA produced by Bacillus subtilis natto, also investigating the variations during the specific cultivation period.

Li et al. present a review delving into the promising realm of biochar, an environmentally friendly material drawing attention for its potential use as a potassium ion anode in batteries. The manuscript explores the transformative possibilities of biochar through modifications, particularly highlighting atomic doping to enhance electrochemical performance. This type of materials exhibits not only efficient energy conduction but also increased potassium storage capacity. The review covers the application of atomically doped biomass carbon materials (BCMs) and recent advancements in pure BCMs, emphasizing considerations for simpler production, reduced costs, and environmental protection. Key challenges in developing BCMs, such as irreversible potassium buildup and electrolyte breakdown, are discussed and potential solutions have also been proposed. Supporting the circular economy model, a beacon of hope for combating the environmental impact of poly(ethylene terephthalate) (PET), a commonly produced and consumed polymer, comes from (Gabrielli et al.). Their proposed approach involves a microwave-assisted recycling process, focused on aminolysis of PET waste to create polyurethane acrylate (PUA) derived coatings. The process utilizes substituted ß-hydroxy amines for chemical depolymerization of PET waste, employing a sodium acetate catalyst. The first step achieves efficient depolymerization of PET within a short time, resulting in the formation of terephthalimide diols. This environmentally friendly method enables the synthesis of a diverse range of diol monomers with customizable organic structures suitable for PUA UV-curable coatings. In this tapestry of research, each article of the present Research Topic not only unravels scientific complexities but also paints a vivid picture of innovation, sustainability, and the transformative power of human ingenuity in the pursuit of a brighter, greener future.


9) Chemical Recycling of Fully Recyclable Bio-Epoxy Matrices and Reuse Strategies: A Cradle-to-Cradle Approach

L.Saitta, G.Rizzo, C.Tosto, G.Cicala, I.Blanco, E.Pergolizzi, R.Ciobanu, G.Recca

Polymers  15(13),  2809  - 2023

DOI: https://doi.org/10.3390/polym15132809
Currently, the epoxy resin market is expressing concerns about epoxy resins’ non-recyclability, which can hinder their widespread use. Moreover, epoxy monomers are synthesized via petroleum-based raw materials, which also limits their use. So, it is crucial to find more environmentally friendly alternative solution for their formulation. Within this context, the aim of this paper is to exploit a Cradle-to-Cradle approach, which consists of remodeling and reshaping the productive cycle of consumer products to make sure that they can be infinitely reused rather than just being recycled with a downgrading of their properties or uses, according to the principle of the complete circular economy. Indeed, after starting with a fully-recyclable bio-based epoxy formulation and assessing its recyclability as having a process yield of 99%, we obtained a recycled polymer that could be reused, mixing with the same bio-based epoxy formulation with percentages varying from 15 wt% to 27 wt%. The formulation obtained was thoroughly characterized by a dynamic-mechanical analysis, differential scanning calorimetry, and flexural tests. This approach had two advantages: (1) it represented a sustainable disposal route for the epoxy resin, with nearly all the epoxy resin recovered, and (2) the obtained recycled polymer could be used as a green component of the primary bio-based epoxy matrix. In the end, by using replicated general factorial designs (as statistical tools) combined with a proper optimization process, after carrying out a complete thermo-mechanical characterization of the developed epoxy formulations, the right percentage of recycled polymer content was selected with the aim of identifying the most performing epoxy matrix formulation in terms of its thermo-mechanical properties.


10) Investigations into the characterization, degradation, and applications of biodegradable polymers by mass spectrometry

P.Rizzarelli, M.Leanza, M.Rapisarda

Mass Spectrometry Reviews   - 2023

DOI: https://doi.org/10.1002/mas.21869
Biodegradable polymers have been getting more and more attention because of their contribution to the plastic pollution environmental issues and to move towards a circular economy. Nevertheless, biodegradable materials still exhibit various disadvantages restraining a widespread use in the market. Therefore, additional research efforts are required to improve their performance. Mass spectrometry (MS) affords a relevant contribution to optimize biodegradable polymer synthesis, to confirm macromolecular structures, to examine along the time the progress of degradation processes and highlight advantages and drawbacks in the extensive applications. This review aims to provide an overview of the MS investigations carried out to support the synthesis of biodegradable polymers, with helpful information on undesirable products or polymerization mechanism, to understand deterioration pathways by the structure of degradation products and to follow drug release and pharmacokinetic. Additionally, it summarizes MS studies addressed on environmental and health issues related to the extensive use of plastic materials, that is, potential migration of additives or microplastics identification and quantification. The paper is focused on the most significant studies relating to synthetic and microbial biodegradable polymers published in the last 15 years, not including agro-polymers such as proteins and polysaccharides.


11) Severe kidney dysfunction in sialidosis mice reveals an essential role for neuraminidase 1 in reabsorption

I.Kho, E.P.Demina, X.Pan, I.Londono, C.W.Cairo, L.Sturiale, A.Palmigiano, A.Messina, D.Garozzo, R.Ung, F.Mac-Way, E.Bonneil, P.Thibault, M.Lemaire, C.R.Morales, A.V.Pshezhetsky

JCI Insight  8(20),  166470  - 2023

DOI: https://doi.org/10.1172/jci.insight.166470
Sialidosis is an ultra-rare multisystemic lysosomal disease caused by mutations in the neuraminidase 1 (NEU1) gene. The severe type II form of the disease manifests with a prenatal/infantile or juvenile onset, bone abnormalities, severe neuropathology, and visceromegaly. A subset of these patients present with nephrosialidosis, characterized by abrupt onset of fulminant glomerular nephropathy. We studied the pathophysiological mechanism of the disease in 2 NEU1-deficient mouse models, a constitutive Neu1-knockout, Neu1ΔEx3, and a conditional phagocyte-specific knockout, Neu1Cx3cr1ΔEx3. Mice of both strains exhibited terminal urinary retention and severe kidney damage with elevated urinary albumin levels, loss of nephrons, renal fibrosis, presence of storage vacuoles, and dysmorphic mitochondria in the intraglomerular and tubular cells. Glycoprotein sialylation in glomeruli, proximal distal tubules, and distal tubules was drastically increased, including that of an endocytic reabsorption receptor megalin. The pool of megalin bearing O-linked glycans with terminal galactose residues, essential for protein targeting and activity, was reduced to below detection levels. Megalin levels were severely reduced, and the protein was directed to lysosomes instead of the apical membrane. Together, our results demonstrated that desialylation by NEU1 plays a crucial role in processing and cellular trafficking of megalin and that NEU1 deficiency in sialidosis impairs megalin-mediated protein reabsorption.


12) HEMA-based macro and microporous materials for CO2 capture

C.Zagni, A.Coco, S.Dattilo, V.Patamia, G.Floresta, R.Fiorenza, G.Curcuruto, T.Mecca, A.Rescifina

Materials Today Chemistry  33,  101715  - 2023

DOI: https://doi.org/10.1016/j.mtchem.2023.101715
New polymeric macroporous materials based on poly 2-hydroxyethyl methacrylate (pHEMA) were synthesized and tested to adsorb CO2. To this purpose, bio and affordable amine-based molecules such as lysine (LYS) and histidine (HIS) were selected as CO2 active sites and used to functionalize HEMA monomer before its crosslinking polymerization. The as-prepared monomers and polymers were characterized by using Nuclear Magnetic Resonance (NMR), Fourier Infrared Spectroscopy (FT-IR), Thermal gravimetric analysis (TGA), and Scanning Electron Microscopy (SEM) equipped with Energy Dispersive X-ray (EDX). Compared to materials reported in the recent literature, all produced ones provide exceptional adsorption capacity in the 162-193 ppm range. In particular, H-HEMA-LYS exhibits the best adsorption grade, well-fitting the Linear Driving Force (LFD) model. H-HEMA-LYS reusability was also tested for up to 5 cycles without significant loss in capture performance. Finally, to get insight into the role of morphology in CO2 adsorption, two diverse macroporous structures were synthesized (hydrogels and cryogels) for both HIS and LYS-based materials. As it turns out, hydrogel formulations of an average area ranging from 15.5 to 230μm2 adsorb 12% more than cryogels with higher values (266-605 μm2).

IPCB graphical abstract



13) Thermomechanical Characterization of an Unsaturated Polyester Vitrimer Synthesized Using a Titanium Transesterification Catalyst

G.Rizzo, L.Saitta, S.Dattilo, C.Tosto, E.Pergolizzi, A.Ivankovic, G.Cicala

ACS Applied Polymer Materials    - 2023

DOI: https://doi.org/10.1021/acsapm.3c01489
Unsaturated polyester resins (UPRs) are widely applied thermosets characterized by good thermo-mechanical properties and excellent chemical resistivity. However, the non-reprocessability of UPRs once cured, together with the increasing amount of their waste, has recently urged research and industries to develop more sustainable substituents. In this work, an unsaturated polyester vitrimer was synthesized and characterized by exploiting titanium (IV) butoxide as the transesterification catalyst. This simple approach demonstrated how the design of a covalent adaptable network could solve the issues related to reprocessability, self-healing, and the recyclability of unsaturated polyester thermosets. Here, an intramolecular transesterification exchange was exploited to confer reparability, reshaping, and thermoforming abilities to commercial polyester. Furthermore, the mechanical properties, the glass transition, and the chemical stability of the polyester resin were preserved despite the conversion of the thermoset matrix into a vitrimeric network.

IPCB graphical abstract



14) Sulfonated Polyether Ketone Membranes Embedded with Nalidixic Acid - An Emerging Controlled Drug Releaser

H.Padinjarathil, V.Vilasini, R.Balasubramanian, C.Drago, S.Dattilo, P.Ramani

Polymers  15(17),  3631  - 2023

DOI: https://doi.org/10.3390/polym15173631
The effective administration of medication has advanced over decades, but the medical community still faces significant demand. Burst release and inadequate assimilation are major drawbacks that affect wound healing efficiency, leading to therapy failure. The widespread application of polymers in biomedical research is significant. The polyether ether ketone (PEEK) family is known for its biocompatibility, inertness, and semi-crystalline thermoplastic properties. In our present studies, we have chosen a member of this family, polyether ketone (PEK), to explore its role as a drug carrier. The PEK backbone was subjected to sulfonation to increase its hydrophilicity. The response surface methodology (RSM) was used to optimize the sulfonation process based on the time, degree of sulfonation, and temperature. The PEK polymer was sulfonated using sulfuric acid at 150 °C for 6 h; back titration was performed to quantify the degree of sulfonation, with 69% representing the maximum sulfonation. SPEK and nalidixic sodium salt were dissolved in dichloroacetic acid to create a thin membrane. The physiological and morphological properties were assessed for the SPEK membrane. The studies on drug release in distilled water and a simulated body fluid over the course of 24 h revealed a controlled, gradual increase in the release rate, correlating with a mathematical model and demonstrating the zero-order nature of the drug release. Hemolysis on the SPEK membrane revealed lower toxicity. The SPEK membrane’s biocompatibility was established using in vitro cytotoxicity tests on the Vero (IC50: 137.85 g/mL) cell lines. These results confirm that the SPEK membranes are suitable for sustained drug release.


15) Packaging effects on highly nutritional value beverage obtained by a mix of typical sicilian fruits in accelerated storage

V.Rizzo, S.Dattilo, S.Barbagallo, C.Puglisi, G.Muratore

Food Packaging and Shelf Life  38,  101138  - 2023

DOI: https://doi.org/10.1016/j.fpsl.2023.101138
Consumers' knowledge has been improved and now they are aware of the importance of consuming healthy food. They know how food and beverages are linked with the proper functioning of their body, so are always more drawn towards consuming healthy products with high nutritional value. The new challenge for soft drink producers is the increasing interest in high nutritive quality products. Therefore such high-quality fruit juice is required to meet consumer needs, but also to ensure safety aspects in order to prolong shelf life. The aim of this research was to understand the most suitable packaging through experimental research to preserve over time the chemical-physical characteristics of a beverage with a high nutritional value obtained by mixing blood orange, pomegranate, and prickly pear juices. The three types of stand-up pouches tested were respectively transparent packaging (PT) (PET/OPA/PE), metalized packaging (PM) (PET/ALU/PET/PE), and totally recyclable packaging (PR) (OPP/OPP/PP). On stand-up pouches, weight loss (%), color intensity, browning index (BI), anthocyanin content (mg/L), total phenols, antioxidant activity (%), and flavonoids were monitored during storage at +45 °C, 65 % RH for accelerated ageing. Results have shown that PR performances were good, it kept high qualitative characteristics among the packaging tested it is the advisable best packaging solution because it certainly offers a valid alternative in terms of performance and a lower environmental impact compared to PM or to traditional packaging (glass), thus representing a more sustainable, effective and innovative choice.

IPCB graphical abstract



16) Total Bio-Based Material for Drug Delivery and Iron Chelation to Fight Cancer through Antimicrobial Activity

V.Patamia, C.Zagni, R.Fiorenza, V.Fuochi, S.Dattilo, P.M.Riccobene, P.M.Furneri, G.Floresta, A.Rescifina

Nanomaterials  13(14),  2036  - 2023

DOI: https://doi.org/10.3390/nano13142036
Bacterial involvement in cancer’s development, along with their impact on therapeutic interventions, has been increasingly recognized. This has prompted the development of novel strategies to disrupt essential biological processes in microbial cells. Among these approaches, metal-chelating agents have gained attention for their ability to hinder microbial metal metabolism and impede critical reactions. Nanotechnology has also contributed to the antibacterial field by offering various nanomaterials, including antimicrobial nanoparticles with potential therapeutic and drug-delivery applications. Halloysite nanotubes (HNTs) are naturally occurring tubular clay nanomaterials composed of aluminosilicate kaolin sheets rolled multiple times. The aluminum and siloxane groups on the surface of HNTs enable hydrogen bonding with biomaterials, making them versatile in various domains, such as environmental sciences, wastewater treatment, nanoelectronics, catalytic studies, and cosmetics. This study aimed to create an antibacterial material by combining the unique properties of halloysite nanotubes with the iron-chelating capability of kojic acid. A nucleophilic substitution reaction involving the hydroxyl groups on the nanotubes? surface was employed to functionalize the material using kojic acid. The resulting material was characterized using infrared spectroscopy (IR), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM), and its iron-chelating ability was assessed. Furthermore, the potential for drug loading - specifically, with resveratrol and curcumin - was evaluated through ultraviolet (UV) analysis. The antibacterial assay was evaluated following CLSI guidelines. The results suggested that the HNTs-kojic acid formulation had great antibacterial activity against all tested pathogens. The outcome of this work yielded a novel bio-based material with dual functionality as a drug carrier and an antimicrobial agent. This innovative approach holds promise for addressing challenges related to bacterial infections, antibiotic resistance, and the development of advanced therapeutic interventions.

IPCB graphical abstract



17) N-acetylneuraminate pyruvate lyase controls sialylation of muscle glycoproteins essential for muscle regeneration and function

A.Da Silva, J.Dort, Z.Orfi, X.Pan, S.Huang, I.Kho, E.Heckel, G.Muscarnera, P.Piet van Vliet, L.Sturiale, A.Messina, D.Romeo, C.D.M.van Karnebeek, X.Wen, A.Hinek, T.Molina, G.Andelfinger, B.Ellezam, Y.Yamanaka, H.J.Olivos, C.R.Morales, J.Joyal, D.J.Lefeber, D.Garozzo, N.A.Dumont, A.V.Pshezhetsky

Science Advances  9(26)  - 2023

DOI: https://doi.org/10.1126/sciadv.ade6308
Deleterious variants in N-acetylneuraminate pyruvate lyase (NPL) cause skeletal myopathy and cardiac edema in humans and zebrafish, but its physiological role remains unknown. We report generation of mouse models of the disease: NplR63C, carrying the human p.Arg63Cys variant, and Npldel116 with a 116-bp exonic deletion. In both strains, NPL deficiency causes drastic increase in free sialic acid levels, reduction of skeletal muscle force and endurance, slower healing and smaller size of newly formed myofibers after cardiotoxin-induced muscle injury, increased glycolysis, partially impaired mitochondrial function, and aberrant sialylation of dystroglycan and mitochondrial LRP130 protein. NPL-catalyzed degradation of sialic acid in the muscle increases after fasting and injury and in human patient and mouse models with genetic muscle dystrophy, demonstrating that NPL is essential for muscle function and regeneration and serves as a general marker of muscle damage. Oral administration of N-acetylmannosamine rescues skeletal myopathy, as well as mitochondrial and structural abnormalities in NplR63C mice, suggesting a potential treatment for human patients.


18) Matrix-Assisted Laser Desorption and Electrospray Ionization Tandem Mass Spectrometry of Microbial and Synthetic Biodegradable Polymers

P.Rizzarelli, M.Rapisarda

Polymers  15(10),  2356  - 2023

DOI: https://doi.org/10.3390/polym15102356
The in-depth structural and compositional investigation of biodegradable polymeric materials, neat or partly degraded, is crucial for their successful applications. Obviously, an exhaustive structural analysis of all synthetic macromolecules is essential in polymer chemistry to confirm the accomplishment of a preparation procedure, identify degradation products originating from side reactions, and monitor chemical-physical properties. Advanced mass spectrometry (MS) techniques have been increasingly applied in biodegradable polymer studies with a relevant role in their further development, valuation, and extension of application fields. However, single-stage MS is not always sufficient to identify unambiguously the polymer structure. Thus, tandem mass spectrometry (MS/MS) has more recently been employed for detailed structure characterization and in degradation and drug release monitoring of polymeric samples, among which are biodegradable polymers. This review aims to run through the investigations carried out by the soft ionization technique matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and electrospray ionization mass spectrometry (ESI-MS) MS/MS in biodegradable polymers and present the resulting information.


19) Preventing lead leakage in perovskite solar cells with a sustainable titanium dioxide sponge

S.Valastro, E.Smecca, G.Mannino, C.Bongiorno, G.Fisicaro, S.Goedecker, V.Arena, C.Spampinato, I.Deretzis, S.Dattilo, A.Scamporrino, S.Carroccio, E.Fazio, F.Neri, F.Bisconti, A.Rizzo, C.Spinella, A.La Magna, A.Alberti

Nature Sustainability   - 2023

DOI: https://doi.org/10.1038/s41893-023-01120-w
As the market uptake of perovskite solar cells (PSCs) is projected to grow rapidly, this clean energy technology will play an increasingly important role in reducing the global carbon footprint. However, one of the major barriers to its full commercialization is the presence of toxic lead (Pb), which enables the current record in photoconversion efficiency but risks being released into the environment when subjected to water or rain. Here we show that Pb leakage can be prevented by applying a transparent titanium dioxide (TiO2) sponge that allows for an efficient Pb sequestration of 58 ng cm-2 nm-1. Already an essential material for PSCs, the additional use of TiO2 through a scalable and solvent-free sputtering process promises extra cost benefits and higher sustainability. Further demonstration of the sponge application with desired thickness on ready-to-use devices, glass and polymeric foils enforces the practical value of the current approach. Our study provides a sustainable solution to one of the environmental and health risks of PSCs and would accelerate their practical applications.


20) Sponge-like macroporous cyclodextrin-based cryogels for controlled drug delivery

C.Zagni, A.Coco, T.Mecca, G.Curcuruto, V.Patamia, K.Mangano, A.Rescifina, S.Carroccio

Materials Chemistry Frontiers   - 2023

DOI: https://doi.org/10.1039/D3QM00139C
New drug delivery systems for wound healing applications based on α /β/γ-cyclodextrin (α/β/γ-CD) acrylic (A) and styrenic (S) monomers have been synthesized and co-polymerized with 2-hydroxyethyl methacrylate (HEMA) via a cryo-polymerization technique. The 3D macroporous cryogels containing hydrophobic cavities were loaded with lomefloxacin (LOM), piroxicam (PIR), and fluconazole (FLU) with a drug loading efficiency (DLE) of up to 78%. Depending on the formulated systems, the release of drugs under different stimuli was achieved, with efficiencies ranging from 23 to 95%. It was demonstrated that the presence of CDs within cryogels determines benefits both in loading capacity and drug delivery. CD derivatives were simultaneously loaded with LOM and PIR and tested for multi-drug release. This non-conventional approach was successfully designed as a proof of concept responding to the need to preserve a sterile target area, facilitating skin repair in wound healing applications. For this purpose, the biocompatibility of CD formulations was ascertained against human fibroblasts.

IPCB graphical abstract



21) Lead Detection in a Gig-Lox TiO2 Sponge by X-ray Reflectivity

V.Arena, E.Smecca, S.Valastro, C.Bongiorno, G.Fisicaro, I.Deretzis, C.Spampinato, G.Mannino, S.Dattilo, A.Scamporrino, S.Carroccio, A.La Magna, A.Alberti

Nanomaterials  13(8),  1397  - 2023

DOI: https://doi.org/10.3390/nano13081397
The importance of lead analysis in environmental matrices becomes increasingly relevant due to the anthropogenic spread of toxic species in nature. Alongside the existing analytical methods to detect lead in a liquid environment, we propose a new dry approach for lead detection and measurement based on its capture from a liquid solution by a solid sponge and subsequent quantification based on X-ray analyses. The detection method exploits the relationship between the electronic density of the solid sponge, which depends on the captured lead, and the critical angle for total reflection of the X-rays. For this purpose, gig-lox TiO2 layers, grown by modified sputtering physical deposition, were implemented for their branched multi-porosity spongy structure that is ideal for capturing lead atoms or other metallic ionic species in a liquid environment. The gig-lox TiO2 layers grown on glass substrates were soaked into aqueous solutions containing different concentrations of Pb, dried after soaking, and finally probed through X-ray reflectivity analyses. It has been found that lead atoms are chemisorbed onto the many available surfaces within the gig-lox TiO2 sponge by establishing stable oxygen bonding. The infiltration of lead into the structure causes an increase in the overall electronic density of the layer and, thus, an increment of its critical angle. Based on the established linear relationship between the amount of lead adsorbed and the augmented critical angle, a standardized quantitative procedure to detect Pb is proposed. The method can be, in principle, applied to other capturing spongy oxides and toxic species.


22) Photo- and Water-Degradation Phenomena of ZnO Bio-Blend Based on Poly(lactic acid) and Polyamide 11

R.Puglisi, A.Scamporrino, N.T.Dintcheva, G.Filippone, E.Bruno, P.Scarfato, P.Cerruti, S.Carroccio

Polymers  15(6),  1434  - 2023

DOI: https://doi.org/10.3390/polym15061434
The goal of this work was to investigate the morphological and chemical?physical changes induced by adding ZnO nanoparticles to bio-based polymeric materials based on polylactic acid (PLA) and polyamide 11 (PA11). Precisely, the photo- and water-degradation phenomena of nanocomposite materials were monitored. For this purpose, the formulation and characterization of novel bio-nanocomposite blends based on PLA and PA11 at a ratio of 70/30 wt.% filled with zinc oxide (ZnO) nanostructures at different percentages were performed. The effect of ZnO nanoparticles (≤2 wt.%) within the blends was thoroughly explored by employing thermogravimetry (TGA), size exclusion chromatography (SEC), matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and scanning and transmission electron microscopy (SEM and TEM). Adding up to 1% wt. of ZnO resulted in a higher thermal stability of the PA11/PLA blends, with a decrement lower than 8% in terms of molar masses (MMs) values being obtained during blend processing at 200 °C. ZnO promoted trans-ester-amide reactions between the two polymers, leading to the formation of PLA/PA11 copolymers. These species could work as compatibilisers at the polymer interface, improving thermal and mechanical properties. However, the addition of higher quantities of ZnO affected such properties, influencing the photo-oxidative behaviour and thus thwarting the material’s application for packaging use. The PLA and blend formulations were subjected to natural aging in seawater for two weeks under natural light exposure. The 0.5% wt. ZnO sample induced polymer degradation with a decrease of 34% in the MMs compared to the neat samples.

IPCB graphical abstract



23) Soluble peptidoglycan fragments produced by Limosilactobacillus fermentum with antiproliferative activity are suitable for potential therapeutic development: A preliminary report

V.Fuochi, M.Spampinato, A.Distefano, A.Palmigiano, D.Garozzo, C.Zagni, A.Rescifina, G.Li Volti, P.M.Furneri

Frontiers in Molecular Biosciences  10,  1082526  - 2023

DOI: https://doi.org/10.3389/fmolb.2023.1082526
Currently, the use of probiotic strains and their products represents a promising innovative approach as an antagonist treatment against many human diseases. Previous studies showed that a strain of Limosilactobacillus fermentum (LAC92), previously defined as Lactobacillus fermentum, exhibited a suitable amensalistic property. The present study aimed to purify the active components from LAC92 to evaluate the biological properties of soluble peptidoglycan fragments (SPFs). The cell-free supernatant (CFS) and bacterial cells were separated after 48 h of growth in MRS medium broth and treated for isolation of SPFs. Antimicrobial activity and proliferation analysis on the human cell line HTC116 were performed using technologies such as xCELLigence, count and viability, and clonogenic analysis. MALDI-MS investigation and docking analysis were performed to determine the molecular structure and hypothetical mode of action, respectively. Our results showed that the antimicrobial activity was mainly due to SPFs. Moreover, the results obtained when investigating the SPF effect on the cell line HCT116 showed substantial preliminary evidence, suggesting their significant cytostatic and quite antiproliferative properties. Although MALDI was unable to identify the molecular structure, it was subsequently revealed by analysis of the bacterial genome. The amino acid structure is called peptide 92. Furthermore, we confirmed by molecular docking studies the interaction of peptide 92 with MDM2 protein, the negative regulator of p53. This study showed that SPFs from the LAC92 strain exerted anticancer effects on the human colon cancer HCT116 cell line via antiproliferation and inducing apoptosis. These findings indicated that this probiotic strain might be a potential candidate for applications in functional products in the future. Further examination is needed to understand the specific advantages of this probiotic strain and improve its functional features to confirm these data. Moreover, deeper research on peptide 92 could increase our knowledge and help us understand if it will be possible to apply to specific diseases such as CRC.


24) Solid-State Preparation and Characterization of 2-Hydroxypropylcyclodextrins-Iodine Complexes as Stable Iodophors

S.Dattilo, F.Spitaleri, D.Aleo, M.G.Saita, A.Patti

Biomolecules  13(3),  474  - 2023

DOI: https://doi.org/10.3390/biom13030474
The use of iodine as antiseptic poses some issues related to its low water solubility and high volatility. Stable solid iodine-containing formulations are highly advisable and currently limited to the povidone-iodine complex. In this study, complexes of molecular iodine with 2-hydroxypropyl α-, β- and γ-cyclodextrins were considered water-soluble iodophors and prepared in a solid state by using three different methods (liquid-assisted grinding, co-evaporation and sealed heating). The obtained solids were evaluated for their iodine content and stability over time in different conditions using a fully validated UV method. The assessment of the actual formation of an inclusion complex in a solid state was carried out by thermal analysis, and the presence of iodine was further confirmed by SEM/EDX and XPS analyses. High levels of iodine content (8.3-10.8%) were obtained with all the tested cyclodextrins, and some influence was exerted by the employed preparation method. Potential use as solid iodophors can be envisaged for these iodine complexes, among which those with 2-hydroxypropyl-α-cyclodextrin were found the most stable, regardless of the preparation technique. The three prepared cyclodextrin?iodine complexes proved effective as bactericides against S. epidermidis.

IPCB graphical abstract



25) Spontaneous polymerization of benzofulvene monomers bearing a 4-Pyridylacetylene substituent in different positions of the benzofulvene scaffold

M.Paolino, M.Saletti, A.Reale, V.Razzano, G.Giuliani, A.Donati, C.Bonechi, G.Giorgi, G.Mercorillo, F.Samperi, W.Mroz, C.Botta, A.Cappelli

European Polymer Journal  189,  111957  - 2023

DOI: https://doi.org/10.1016/j.eurpolymj.2023.111957
Two benzofulvene derivatives bearing a 4-pyridylacetylene substituent in different positions (i. e. 2 and 6) of the benzofulvene scaffold are designed and synthesized to evaluate the effects on the spontaneous solid-state polymerization of the presence of the same substituent in two different key positions of the 3-phenylbenzofulvene moiety. Both the benzofulvene derivatives showed the tendency to polymerize spontaneously in the consequence of solvent removal under reduced pressure without the addition of catalysts or initiators. The macromolecular structure of the stemming polymeric materials was investigated by NMR spectroscopy and MALDI-TOF mass spectrometry. Both NMR and MALDI-TOF studies confirmed the polymeric nature of the materials and suggested for the polybenzofulvene derivative bearing the 4-pyridylacetylene substituent in positions 6 a higher structural homogeneity with respect to the one bearing the same substituent in position 2. The photophysical characterization of the most homogeneous polybenzofulvene derivative led to the discovery of its outstanding hole mobility value, which was found to be around one order of magnitude higher than that previously measured for two oligothiophene-based polybenzofulvene derivatives and almost two orders of magnitude higher than that of poly(vinylcarbazole), commonly used as hole-transporter matrix. This result places the new polybenzofulvene derivative in an outstanding position as a promising material for field-effect transistor (FET) device applications.

IPCB graphical abstract



26) Temperature Responsive Copolymers Films of Polyether and Bio-Based Polyamide Loaded with Imidazolium Ionic Liquids for Smart Packaging Applications

D.Zampino, G.Clarizia, P.Bernardo

Polymers  15(5),  1147  - 2023

DOI: https://doi.org/10.3390/polym15051147
Temperature-responsive materials are highly interesting for temperature-triggered applications such as drug delivery and smart packaging. Imidazolium Ionic Liquids (ILs), with a long side chain on the cation and a melting temperature of around 50 °C, were synthetized and loaded at moderate amounts (up to 20 wt%) within copolymers of polyether and a bio-based polyamide via solution casting. The resulting films were analyzed to assess their structural and thermal properties, and the gas permeation changes due to their temperature-responsive behavior. The splitting of FT-IR signals is evident, and, in the thermal analysis, a shift in the glass transition temperature (Tg) for the soft block in the host matrix towards higher values upon the addition of both ILs is also observed. The composite films show a temperature-dependent permeation with a step change corresponding to the solid-liquid phase change in the ILs. Thus, the prepared polymer gel/ILs composite membranes provide the possibility of modulating the transport properties of the polymer matrix simply by playing with temperature. The permeation of all the investigated gases obeys an Arrhenius-type law. A specific permeation behavior, depending on the heating-cooling cycle sequence, can be observed for carbon dioxide. The obtained results indicate the potential interest of the developed nanocomposites as CO2 valves for smart packaging applications.


27) Polymer Blends Based on 1-Hexadecyl-3-methyl Imidazolium 1,3-Dimethyl 5-Sulfoisophthalate Ionic Liquid: Thermo-Mechanical, Surface Morphology and Antibacterial Properties

D.Zampino, F.Samperi, M.Mancuso, T.Ferreri, L.Ferreri, S.Dattilo, E.F.Mirabella, D.C.Carbone, G.Recca, A.Scamporrino, E.Novello, C.Puglisi

Polymers  15(4),  970  - 2023

DOI: https://doi.org/10.3390/polym15040970
In this study, antibacterial polymer blends based on Polyvinyl Chloride (PVC) and Polystyrene-Ethylene-Butylene-Styrene (SEBS), loaded with the ionic liquid (IL) 1-hexadecyl-3-methyl imidazolium 1,3-dimethyl 5-sulfoisophthalate (HdmimDMSIP) at three different concentrations (1%, 5%, and 10%), were produced. The IL/blends were characterized by their thermo-mechanical properties, surface morphology, and wettability. IL release from the blends was also evaluated. The agar diffusion method was used to test the antibacterial activity of the blends against Staphylococcus epidermidis and Escherichia coli. Results from thermal analyses showed compatibility between the IL and the PVC matrix, while phase separation in the SEBS/IL blends was observed. These results were confirmed using PY-GC MS data. SEM analyses highlighted abundant IL deposition on PVC blend film surfaces containing the IL at 5-10% concentrations, whereas the SEBS blend film surfaces showed irregular structures similar to islands of different sizes. Data on water contact angle proved that the loading of the IL into both polymer matrices induced higher wettability of the blends’ surfaces, mostly in the SEBS films. The mechanical analyses evidenced a lowering of Young’s Modulus, Tensile Stress, and Strain at Break in the SEBS blends, according to IL concentration. The PVC/IL blends showed a similar trend, but with an increase in the Strain at Break as IL concentration in the blends increased. Both PVC/IL and SEBS/IL blends displayed the best performance against Staphylococcus epidermidis, being active at low concentration (1%), whereas the antimicrobial activity against Escherichia coli was lower than that of S. epidermidis. Release data highlighted an IL dose-dependent release. These results are promising for a versatile use of these antimicrobial polymers in a variety of fields.


28) Higher frequency of TMEM199-CDG in the southern mediterranean area is associated with c.92G>C (p.Arg31Pro) mutation

A.Fiumara, A.Sapuppo, L.Ferri, A.Arena, A.Prato, D.Garozzo, L.Sturiale, A.Morrone, R.Barone

European Journal of Medical Genetics  66(3),  104709  - 2023

DOI: https://doi.org/10.1016/j.ejmg.2023.104709
Congenital disorders of glycosylation (CDG) are genetic multisystem diseases, characterized by defective glycoconjugate synthesis. A small number of CDG with isolated liver damage have been described, such as TMEM199-CDG, a non-encephalopathic liver disorder with Wilson disease-like phenotype. Only eight patients with TMEM199-CDG have been described including seven Europeans (originating from Greece and Italy) and one Chinese. Three patients from southern Italy (Campania) shared the same known missense mutation pathogenetic variant NM_152464.3:c. 92G > C (p.Arg31Pro), also found in a Greek patient. Here we report a new patient from southern Italy (Sicily), with a homozygous c.92G > C p.(Arg31Pro) variant in TMEM199. The patient’s phenotype is characterized by mild non-progressive hepatopathy with a normal hepatic echo structure. A persistent increase in serum transaminases, total and low-density lipoprotein cholesterol and low serum ceruloplasmin and copper levels and normal urinary copper excretion were observed. Matrix-assisted laser desorption/ionization mass spectrometry analyses showed abnormal N- and O- protein glycosylation, indicative of a Golgi processing defect and supporting the function of TMEM199 in maintaining Golgi homeostasis. TMEM199-CDG is an ultra-rare CDG relatively frequent in the southern Mediterranean area (7 in 9 patients, 77%). It is mainly associated with the c.92G > C (p.Arg31Pro) pathogenetic allele globally reported in 4 out of 7 families (57%), including one from Greece and three unrelated families from southern Italy. The almost uniform clinical phenotype described in patients with TMEM199-CDG appears to reflect a higher prevalence of the same variant in patients from the southern Mediterranean area.


29) Calix[4]arene Derivative for Iodine Capture and Effect on Leaching of Iodine through Packaging

L.Ferreri, M.Rapisarda, M.Leanza, C.Munzone, N.D’Antona, G.M.L.Consoli, P.Rizzarelli, E.Spina

Molecules  28(4),  1869  - 2023

DOI: https://doi.org/10.3390/molecules28041869
A hydrophobic calix[4]arene derivative was investigated for its iodine (I2) capture efficiency from gaseous and liquid phase. The iodine uptake was followed by UV-vis spectroscopy. Additionally, the influence of the calix[4]arene derivative-polyolefin system on the leaching of iodine through packaging from a povidone-iodine-based (PVP-I) formulation was evaluated. In fact, iodine is a low-cost, multi-target, and broad-spectrum antiseptic. However, it is volatile, and the extended storage of I2-based formulations is challenging in plastic packaging. Here, we investigated the possibility of reducing the loss of I2 from an iodophor formulation by incorporating 4-tert-butylcalix [4]arene-tetraacetic acid tetraethyl ester (CX) and its iodine complex in high-density polyethylene (HDPE) or polypropylene (PP) via a swelling procedure. Surface and bulk changes were monitored by contact angle, thermogravimetric analysis (TGA), and UV-vis diffuse reflectance spectra. The barrier effect of the different polymeric systems (embedded with CX, iodine-CX complex, or I2) was evaluated by monitoring the I2 retention in a buffered PVP-I solution by UV-vis spectroscopy. Overall, experimental data showed the capability of the calix[4]arene derivative to complex iodine in solution and the solid state and a significant reduction in the iodine leaching by the PP-CX systems.

IPCB graphical abstract



30) Design of an Antibiotic-Releasing Polymer: Physicochemical Characterization and Drug Release Patterns

H.Padinjarathil, S.Mudradi, R.Balasubramanian, C.Drago, S.Dattilo, N.K.Kothurkar, P.Ramani

Membranes  13(1),  102  - 2023

DOI: https://doi.org/10.3390/membranes13010102
Conventional drug delivery has its share of shortcomings, especially its rapid drug release with a relatively short duration of therapeutic drug concentrations, even in topical applications. Prolonged drug release can be effectively achieved by modifying the carrier in a drug delivery system. Among the several candidates for carriers studied over the years, poly (ether ether ketone), a biocompatible thermoplastic, was chosen as a suitable carrier. Its inherent hydrophobicity was overcome by controlled sulfonation, which introduced polar sulfonate groups onto the polymer backbone. Optimization of the sulfonation process was completed by the variation of the duration, temperature of the sulfonation, and concentration of sulfuric acid. The sulfonation was confirmed by EDS and the degree of sulfonation was determined by an NMR analysis (61.6% and 98.9%). Various physical properties such as morphology, mechanical strength, and thermal stability were studied using scanning electron microscopy, tensile testing, and thermogravimetric analysis. Cytotoxicity tests were performed on the SPEEK samples to study the variation in biocompatibility against a Vero cell line. The drug release kinetics of ciprofloxacin (CP) and nalidixic acid sodium salt (NA)-loaded membranes were studied in deionized water as well as SBF and compared against the absorbance of standardized solutions of the drug. The data were then used to determine the diffusion, distribution, and permeability coefficients. Various mathematical models were used to fit the obtained data to establish the order and mechanism of drug release. Studies revealed that drug release occurs by diffusion and follows zero-order kinetics.


31) A novel material based on an antibacterial choline-calixarene nanoassembly embedded in thin films

L.Ferreri, G.M.L.Consoli, G.Clarizia, D.Zampino, A.Nostro, G.Granata, G.Ginestra, M.L. Giuffrida, S.Zimbone, P.Bernardo

Journal of Materials Science   57,  20685-20701  - 2022

DOI: https://doi.org/10.1007/s10853-022-07868-4
Supramolecular chemistry is one of the current strategies for producing advanced materials. With the aim to develop new Thin-Films with antibacterial activity, we embedded an amphiphilic choline-calix[4]arene possessing antibacterial properties in polymeric Thin-Films based on polyether-co-amide matrix (Pebax®2533). The loading of the calix[4]arene derivative in the film was performed by solution casting. The amount of calixarene additive in the films was in the range of 0.5-5 wt%. The self-supported Thin-Films were characterized by investigating phase miscibility, morphology, spectral properties, and gas transport. The release of the calixarene derivative from the films was studied in a biomimetic medium as PBS (10 mM, pH 7.4). The presence of the additive did not affect the thermal stability of the copolymer, whereas it induced an increase in crystallinity, wettability, and gas permeability of the blend films according to its concentration. The antibacterial activity of the films was evaluated in vitro against Escherichia coli and Staphylococcus aureus strains, representative of Gram-negative and Gram-positive bacteria. The developed films displayed antibacterial activity against both strains. In particular, Pebax® - 5 wt% Chol-Calix caused within 10 h a reduction in E. coli and S. aureus of 2.57 and 2 log CFU/mL, respectively. The potential toxicity of the films was also tested on mouse embryonic fibroblasts NIH/3T3. Pebax®2533/calixarene derivative combination appears a promising approach for the development of novel flexible antibacterial materials.

IPCB graphical abstract



32) Synthesis, Characterization, and Soil Burial Degradation of Biobased Polyurethanes

A.Zuliani, M.Rapisarda, D.Chelazzi, P.Baglioni, P.Rizzarelli

Polymers  14(22),  4948  - 2022

DOI: https://doi.org/10.3390/polym14224948
There is an urgent need for developing degradable polymeric systems based on bio-derived and sustainable materials. In recent years, polyurethanes derived from castor oil have emerged due to the large availability and sustainable characteristics of castor oil. However, these polymers are normally prepared through tedious and/or energy-intensive procedures or using high volatile and/or toxic reagents such as volatile isocyanates or epoxides. Furthermore, poor investigation has been carried out to design castor oil derived polyurethanes with degradable characteristics or thorough specifically sustainable synthetic procedures. Herein, castor oil-derived polyurethane with more than 90% biomass-derived carbon content and enhanced degradable features was prepared through a simple, eco-friendly (E-factor: 0.2), and scalable procedure, employing a recently developed commercially available biomass-derived (61% bio-based carbon content) low-volatile polymeric isocyanate. The novel material was compared with a castor oil derived-polyurethane prepared with a commercially available fossil-based isocyanate counterpart. The different castor oil-derived polyurethanes were investigated by means of water uptake, soil burial degradation, and disintegration tests in compost. Characterization analyses, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM), were carried out both prior to and after degradation tests. The results suggest potential applications of the degradable castor oil-derived polyurethane in different fields, such as mulch films for agricultural purposes.

IPCB graphical abstract



33) Full Recycling and Re-Use of Bio-Based Epoxy Thermosets: Chemical and Thermomechanical Characterization of the Recycled Matrices

S.Dattilo, G.Cicala, P.M.Riccobene, C.Puglisi, L.Saitta

Polymers  14(22),  4828  - 2022

DOI: https://doi.org/10.3390/polym14224828
High performances of thermosets deriving from their covalent intermolecular cross-link bonds result in their low recyclability hindering the full exploitation of a truly circular approach for cured thermosets. In this experimental work, the recyclability of a bio-based fully recyclable epoxy resin using a mild chemical recycling process was demonstrated. The recycled polymer obtained was fully characterized to ascertain its structure and properties. MALDI (Matrix-Assisted Laser Desorption/Ionization), GPC (Gel Permeation Chromatography) and NMR (Nuclear Magnetic Resonance) spectroscopy to determine the chemical structure of the recycled polymer were used. The thermomechanical properties of the cured virgin network and of the recycled product obtained were measured by DSC (Differential Scanning Calorimetry) and DMA (Dynamic Mechanical Analysis). Thermogravimetric analysis of the recycled polymer was also performed. The recycled polymer was transformed into a polyurethane by reacting it with an isocyanate. The synthetized polyurethane obtained therefrom was thoroughly characterized by thermogravimetric analysis. This approach proved the possibility to up-scale the recycled product making it available for novel applications exploiting its re-use.

IPCB graphical abstract



34) Single and dual polymeric sponges for emerging pollutants removal

C.Zagni, S.Dattilo, T.Mecca, C.Gugliuzzo, A.Scamporrino, V.Privitera, R.Puglisi, S.Carroccio

European Polymer journal  179  - 2022

DOI: https://doi.org/10.1016/j.eurpolymj.2022.111556
A platform of polymeric cryogels based on methacrylic acid (C-mA) meglumine (C-megl), lysine (C-lys), and 2-hydroxy ethyl methacrylate (C-ph), as well as a combination thereof having both negatively and positively charged moieties, have been synthesized and used to efficiently remove emerging contaminants from water. Their peculiar properties in sequestering antibiotics (Levofloxacin, Ampicillin, Doxycycline), anti-inflammatory (Piroxicam), antifungal (Fluconazole), anti-parasite (Moxidectin), pesticides (2,4D) and dyes (Thymol blue, Methylene Violet) were tested taking into account their ionic nature in solution. The adsorption experiments performed in batches at different pH and pollutant concentrations have demonstrated the outstanding ability of these macroporous soft systems in complexing molecules by the instauration of various binding forces, also in the presence of inorganic species such as arsenic (as arseniate). In addition, it was demonstrated as the novel dual-material, ad-hoc synthesized by using opposite charge cryogels, can simultaneously remove antagonist dyes in a single and fast cycle. Besides, a quasi-total release of the target molecules was achieved by changing pH, allowing the regeneration of the macroporous sponges for multiple re-uses without losing their performance. The latter peculiar feature may be adopted for drug delivery applications since the release can be modulated and programmed by a specific pH stimulus.

IPCB graphical abstract



35) Polymer aging affects the bioavailability of microplastics-associated contaminants in sea urchin embryos

M.V.Di Natale, S.Carroccio, S.Dattilo, M.Cocca, A.Nicosia, M.Torri, C.D.Bennici, M.Musco, T.Masullo, S.Russo, A.Mazzola, A.Cuttitta

Chemosphere  309(1)  - 2022

DOI: https://doi.org/10.1016/j.chemosphere.2022.136720
Microplastics (MPs) in the marine environment undergo complex weathering factors that can affect their ability to interact with different coexisting environmental contaminants (termed here co-contaminants). In this study, the influence of artificially aging using UV on the sorption of a complex mixture of co-contaminants onto MPs was investigated in order to provide meaningful hypotheses on their individual and combined toxicities on sea urchin embryos. A mixture of artificially aged MPs (PS particles and PA microfibers) combined with 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), or Cd or Cu, both alone and in a mix, were used to expose embryos of Paracentrotus lividus. The effects of polymer aging on co-contaminants bioavailability were assessed by measuring changes in the transcriptional profile of genes involved in oxidative-stress response and skeletogenic and endo-mesodermal specification. Changes in the sorption ability of MPs to co-contaminants in the aqueous phase highlighted that aging did not affect the sorption of BDE-47 and Cd on MPs, although a certain influence on Cu sorption was found. Despite no morphological effects in embryos at the gastrula stage after MPs/contaminants combinatorial exposure emerged, the greatest influence of the aging process was mainly found for combined exposures which included BDE-47. Finally, the exposure to multiple contaminants generated transcriptional profiles poorly related to those activated by single contaminant, at times suggesting a mixture-dependent different aging influence. These results open new scenarios on the controversial role of vector of co-contaminants for MPs, especially when complex and different types of mixtures were considered.

IPCB graphical abstract



36) Phenotypic and genetic spectrum of ATP6V1A encephalopathy: a disorder of lysosomal homeostasis

R.Guerrini, D.Mei, K.Kerti-Szigeti, S.Pepe, M.Kay Koenig, G.Von Allmen, M.T Cho, K.McDonald, J.Baker, V.Bhambhani, Z.Powis, L.Rodan, R.Nabbout, G.Barcia, J.A.Rosenfeld, C.A.Bacino, C.Mignot, L.H.Power, C.J.Harris, D.Marjanovic, R.S.Møller, T.B.Hammer, The DDD Study, R.K.Filppula, P.Vieira, C.Hildebrandt, S.Sacharow, Undiagnosed Diseases Network, L.Maragliano, F.Benfenati, K.Lachlan, A.Benneche, F.Petit, J.M.De Sainte Agathe, B.Hallinan, Y.Si, I.M.Wentzensen, F.Zou, V.Narayanan, N.Matsumoto, A.Boncristiano, G.La Marca, M.Kato, K.Anderson, C.Barba, L.Sturiale, D.Garozzo, R.Bei, ATP6V1A collaborators, L.Masuelli, V.Conti, G.Novarino, A.Fassio

Brain  145(8),  2687-2703  - 2022

DOI: https://doi.org/10.1093/brain/awac145

Vacuolar-type H+-ATPase (V-ATPase) is a multimeric complex present in a variety of cellular membranes that acts as an ATP-dependent proton pump and plays a key role in pH homeostasis and intracellular signalling pathways. In humans, 22 autosomal genes encode for a redundant set of subunits allowing the composition of diverse V-ATPase complexes with specific properties and expression. Sixteen subunits have been linked to human disease.

Here we describe 26 patients harbouring 20 distinct pathogenic de novo missense ATP6V1A variants, mainly clustering within the ATP synthase α/β family-nucleotide-binding domain. At a mean age of 7 years (extremes: 6 weeks, youngest deceased patient to 22 years, oldest patient) clinical pictures included early lethal encephalopathies with rapidly progressive massive brain atrophy, severe developmental epileptic encephalopathies and static intellectual disability with epilepsy. The first clinical manifestation was early hypotonia, in 70%; 81% developed epilepsy, manifested as developmental epileptic encephalopathies in 58% of the cohort and with infantile spasms in 62%; 63% of developmental epileptic encephalopathies failed to achieve any developmental, communicative or motor skills. Less severe outcomes were observed in 23% of patients who, at a mean age of 10 years and 6 months, exhibited moderate intellectual disability, with independent walking and variable epilepsy. None of the patients developed communicative language. Microcephaly (38%) and amelogenesis imperfecta/enamel dysplasia (42%) were additional clinical features. Brain MRI demonstrated hypomyelination and generalized atrophy in 68%. Atrophy was progressive in all eight individuals undergoing repeated MRIs.

Fibroblasts of two patients with developmental epileptic encephalopathies showed decreased LAMP1 expression, Lysotracker staining and increased organelle pH, consistent with lysosomal impairment and loss of V-ATPase function. Fibroblasts of two patients with milder disease, exhibited a different phenotype with increased Lysotracker staining, decreased organelle pH and no significant modification in LAMP1 expression. Quantification of substrates for lysosomal enzymes in cellular extracts from four patients revealed discrete accumulation. Transmission electron microscopy of fibroblasts of four patients with variable severity and of induced pluripotent stem cell-derived neurons from two patients with developmental epileptic encephalopathies showed electron-dense inclusions, lipid droplets, osmiophilic material and lamellated membrane structures resembling phospholipids. Quantitative assessment in induced pluripotent stem cell-derived neurons identified significantly smaller lysosomes.

ATP6V1A-related encephalopathy represents a new paradigm among lysosomal disorders. It results from a dysfunctional endo-lysosomal membrane protein causing altered pH homeostasis. Its pathophysiology implies intracellular accumulation of substrates whose composition remains unclear, and a combination of developmental brain abnormalities and neurodegenerative changes established during prenatal and early postanal development, whose severity is variably determined by specific pathogenic variants.



37) CAMLG-CDG: a novel congenital disorder of glycosylation linked to defective membrane trafficking

M.P.Wilson, Z.Durin, Ö.Unal, B.G.Ng, T.Marrecau, L.Keldermans, E.Souche, D.Rymen, M.Gündüz, G.Köse, L.Sturiale, D.Garozzo, H.H.Freeze, J.Jaeken, F.Foulquier, G.Matthijs

Human molecular genetics  31(15),  2571-2581  - 2022

DOI: https://doi.org/10.1093/hmg/ddac055
The transmembrane domain recognition complex (TRC) pathway is required for the insertion of C-terminal tail-anchored (TA) proteins into the lipid bilayer of specific intracellular organelles such as the endoplasmic reticulum (ER) membrane. In order to facilitate correct insertion, the recognition complex (consisting of BAG6, GET4 and UBL4A) must first bind to TA proteins and then to GET3 (TRC40, ASNA1), which chaperones the protein to the ER membrane. Subsequently, GET1 (WRB) and CAML form a receptor that enables integration of the TA protein within the lipid bilayer. We report an individual with the homozygous c.633 + 4A>G splice variant in CAMLG, encoding CAML. This variant leads to aberrant splicing and lack of functional protein in patient-derived fibroblasts. The patient displays a predominantly neurological phenotype with psychomotor disability, hypotonia, epilepsy and structural brain abnormalities. Biochemically, a combined O-linked and type II N-linked glycosylation defect was found. Mislocalization of syntaxin-5 in patient fibroblasts and in siCAMLG deleted Hela cells confirms this as a consistent cellular marker of TRC dysfunction. Interestingly, the level of the v-SNARE Bet1L is also drastically reduced in both of these models, indicating a fundamental role of the TRC complex in the assembly of Golgi SNARE complexes. It also points towards a possible mechanism behind the hyposialylation of N and O-glycans. This is the first reported patient with pathogenic variants in CAMLG. CAMLG-CDG is the third disorder, after GET4 and GET3 deficiencies, caused by pathogenic variants in a member of the TRC pathway, further expanding this novel group of disorders.


38) Influence of Calcium Carbonate Nanoparticles on the Soil Burial Degradation of Polybutyleneadipate-Co-Butylenetherephthalate Films

M.Rapisarda, M.Ch.Mistretta, M.Scopelliti, M.Leanza, F.P.La Mantia, P.Rizzarelli

Nanomaterials  12(13),  2275  - 2022

DOI: https://doi.org/10.3390/nano12132275
A polybutyleneadipate-co-butylenetherephthalate (PBAT) sample, commercially known as Ecoflex®, was processed via melt extrusion with CaCO3 nanoparticles coated with a hydrophobic coating. Blown films of PBAT and two composites with nanofiller (2% and 5%wt) were prepared and degradation tests in soil at 30 °C up to 180 days were carried out with weight loss measurements. Furthermore, biodegradation test according to ISO 14851 was carried out at 30 °C. The effect of CaCO3 on soil burial degradation was assessed by surface wettability and SEM. ATR-FTIR and XPS analyses highlighted chemical modifications induced by soil degradation. CaCO3 nanoparticles decreased surface wettability and discouraged the disintegration in soil. Interestingly, SEM images after soil degradation highlighted in the nanocomposite films selective zones of disintegration. XPS showed an increasing peak area C 1s ratio of C-O to C=O with degradation time. Moreover, after the soil burial test, carbonyl index determined by ATR-FTIR increased in both nanocomposites. In fact, the addition of CaCO3 leads to a rise in the carbonyl zone due to the presence of the carbonate group. Remarkably, FTIR data after soil degradation showed an enrichment of the aromatic content, a preferential cleavage and erosion of the aliphatic moiety in PBAT films, amplified by the presence of the CaCO3 nanofiller.

IPCB graphical abstract



39) Recycled (Bio)Plastics and (Bio)Plastic Composites: A Trade Opportunity in a Green Future

E.Morici, S.Carroccio, E.Bruno, P.Scarfato, G.Filippone, N.Tz.Dintcheva

Polymers  14(10),  2038  - 2022

DOI: https://doi.org/10.3390/polym14102038
Today’s world is at the point where almost everyone realizes the usefulness of going green. Due to so-called global warming, there is an urgent need to find solutions to help the Earth and move towards a green future. Many worldwide events are focusing on the global technologies in plastics, bioplastic production, the recycling industry, and waste management where the goal is to turn plastic waste into a trade opportunity among the industrialists and manufacturers. The present work aims to review the recycling process via analyzing the recycling of thermoplastic, thermoset polymers, biopolymers, and their complex composite systems, such as fiber-reinforced polymers and nanocomposites. Moreover, it will be highlighted how the frame of the waste management, increasing the materials specificity, cleanliness, and a low level of collected material contamination will increase the potential recycling of plastics and bioplastics-based materials. At the same time, to have a real and approachable trade opportunity in recycling, it needs to implement an integrated single market for secondary raw materials

IPCB graphical abstract



40) Sequencing Biodegradable and Potentially Biobased Polyesteramide of Sebacic Acid and 3-Amino-1-propanol by MALDI TOF-TOF Tandem Mass Spectrometry

P.Rizzarelli, S.La Carta, E.F.Mirabella, M.Rapisarda, G.Impallomeni

Polymers  14(8),  1500  - 2022

DOI: https://doi.org/10.3390/polym14081500
Biodegradable and potentially biobased polyesteramide oligomers (PEA-Pro), obtained from melt condensation of sebacic acid and 3-amino-1-propanol, were characterized by nuclear magnetic resonance (NMR), matrix assisted laser desorption/ionization-time of flight/time of flight-mass spectrometry/mass spectrometry (MALDI-TOF/TOF-MS/MS), thermogravimetric analysis (TGA), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). NMR analysis showed the presence of hydroxyl and amino terminal groups as well as carboxylic groups of the sebacate moiety. Hydroxyl and carboxyl termination had the same abundance, while the amine termination was 2.7-times less frequent. Information regarding the fragmentation pathways and ester/amide bond sequences was obtained by MALDI-TOF/TOF-MS/MS analysis performed on sodiated adducts of cyclic species and linear oligomers. Different end groups did not influence the observed fragmentation. Three fragmentation pathways were recognized. The β-hydrogen-transfer rearrangement, which leads to the selective scission of the -O-CH2- bonds, was the main mechanism. Abundant product ions originating from -CH2-CH2- (β-γ) bond cleavage in the sebacate moiety and less abundant ions formed by -O-CO- cleavages were also detected. TGA showed a major weight loss (74%) at 381 °C and a second degradation step (22% weight loss) at 447 °C. Py-GC/MS performed in the temperature range of 350-400 °C displayed partial similarity between the degradation products and the main fragments detected in the MALDI-TOF/TOF-MS/MS experiments. Degradation products derived from amide bonds were related to the formation of CN groups, in agreement with the literature.

IPCB graphical abstract



41) Superparamagnetic Iron Oxide Nanoparticle Nanodevices Based on Fe3O4 Coated by Megluminic Ligands for the Adsorption of Metal Anions from Water

S.Scurti, S.Dattilo, D.Gintsburg, L.Vigliotti, A.Winkler, S.Carroccio, D.Caretti

ACS Omega   - 2022

DOI: https://doi.org/10.1021/acsomega.2c00558
The uptake ability toward arsenic(V), chromium(VI), and boron(III) ions of ad hoc functionalized magnetic nanostructured devices has been investigated. To this purpose, ligands based on meglumine have been synthesized and used to coat magnetite nanoparticles (Fe3O4) obtained by the co-precipitation methodology. The as-prepared hybrid material was characterized by infrared spectroscopy (IR), X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy combined with energy-dispersive X-ray analysis. Moreover, its magnetic hysteresis properties were measured to evaluate its magnetic properties, and the adsorption kinetics and isothermal models were applied to discern between the different adsorption phenomena. Specifically, the better fitting was observed by the Langmuir isotherm model for all metal ions tested, highlighting a higher uptake in arsenic (28.2 mg/g), chromium (12.3 mg/g), and boron (23.7 mg/g) sorption values if compared with other magnetic nanostructured materials. After adsorption, an external magnetic stimulus can be used to efficiently remove nanomaterials from the water. Finally the nanomaterial can be reused up to five cycles and regenerated for another three cycles.

IPCB graphical abstract



42) Spontaneous polymerization of benzofulvene derivatives bearing complexed or un-complexed pyridine rings

M.Paolino, M.Saletti, A.Reale, V.Razzano, G.Giuliani, A.Donati, C.Bonechi, G.Giorgi, A.Atrei, M.Mauro, A.Scamporrino, F.Samperi, E.Fois, G.Tabacchi, C.Botta, A.Cappelli

European Polymer Journal  169,  111137  - 2022

DOI: https://doi.org/10.1016/j.eurpolymj.2022.111137
Benzofulvene derivatives bearing complexed and un-complexed pyridine rings are designed and synthesized to assess the effects on the spontaneous solid-state polymerization of the presence in position 6 of the 3-phenylbenzofulvene moiety of bulky substituents capable of establishing metallophilic interactions. Both the benzofulvene monomers are found to polymerize spontaneously upon solvent removal under reduced pressure in the apparent absence of catalysts or initiators. The resulting polybenzofulvene derivatives are characterized by NMR spectroscopy, MALDI-TOF mass spectrometry, and in photophysical studies.

IPCB graphical abstract



43) Carbazole-Pyridazine copolymers and their rhenium complexes: Effect of the molecular structure on the electronic properties

S.Zappia, L.Veronese, A.Fornic, S.Dattilo, F.Samperi, J.Dagare, T.M.Brown, M.Panigati, S.Destri

European Polymer Journal  168,  111095  - 2022

DOI: https://doi.org/10.1016/j.eurpolymj.2022.111095
Two new push-pull copolymers, poly[N-(9-heptadecanyl)carbazole-2,7-diyl-alt-phthalazine- 5,8-diyl] (P1) and poly[N-(9-heptadecanyl)carbazole-2,7-diyl-alt-thieno[3,4-d]pyridazine- 5,7-diyl] (P2), were synthetized by means of a Suzuki polycondensation. The molecular characterization with 1H NMR and MALDI-MS showed enchainment defects in the polymer backbones depending on the synthetic conditions (catalyst and temperature). Both carbazole-carbazole and diazine-diazine homocoupling defects occurred, particularly in the case of P2. For P1, instead, almost homocoupling-free material was obtained. Exploiting the metal coordination capability of the pyridazine ring, corresponding dinuclear rhenium-based metallopolymers, ReP1 and ReP2, were also synthetized. All materials were investigated with experimental techniques (UV-vis spectroscopy, photoluminescence, cyclic voltammetry) and corroborated by theoretical studies (DFT and TD-DFT), including a qualitative evaluation of the effects of backbone defects on the electronic properties of the polymers. They were also tested in organic photovoltaic (OPV) devices. The wide energy gaps (Eg) accompanied with a low absorption coefficient for the band in the visible range reduced the harvesting capability of the copolymers. These drawbacks were partially overcome in the metallopolymers. The low device performance was mainly attributable to the low solubility of the metallopolymers in the organic solvents.

IPCB graphical abstract



44) COG6-CDG: Novel variants and novel malformation

L.Cirnigliaro, P.Bianchi, L.Sturiale, D.Garozzo, G.Mangili, L.Keldermans, R.Rizzo, G.Matthijs, A.Fiumara, J.Jaeken, R.Barone

Birth Defects Research  114(5-6),  165-174  - 2022

DOI: https://doi.org/10.1002/bdr2.1981
Background
Deficiency of Conserved Oligomeric Golgi (COG) subunits (COG1?8) is characterized by both N- and O-protein glycosylation defects associated with destabilization and mislocalization of Golgi glycosylation machinery components (COG-CDG). Patients with COG defects present with neurological and multisystem involvement and possible malformation occurrence. Eighteen patients with COG6-CDG (COG6 mutations) were reported to date. We describe a patient with COG6-CDG with novel variants and a novel clinical feature namely a congenital recto-vaginal fistula.
Methods
In-depth serum N- and O-glycosylation structural analyses were conducted by MALDI-TOF mass spectrometry. COG6 variants were identified by a gene panel and confirmed by Sanger sequencing.
Results
This female newborn presented with facial dysmorphism, distal arthrogryposis and recurrent stool discharges per vaginam. A double-contrast barium-enema X-ray study revealed a dehiscence (approximately 5 mm) at the anterior wall of the rectal ampoule communicating with the vagina consistent with a recto-vaginal fistula. She had developmental delay, corpus callosum dysgenesis, liver and gastrointestinal involvement, hyperthermia episodes and early demise. Serum N- and O-glycosylation analyses pointed to a profound Golgi disarrangement. We identified two novel variants in COG6: a deletion of 1 bp mutation c.823delA creating a shift in the reading frame and a premature stop codon and a 3 bp deletion (c.1141_1143delCTC) producing an in-frame deletion of 1 amino acid.
Conclusion
The congenital recto-vaginal fistula is a rare type of anorectal malformation that, to our knowledge, has not been reported in patients with a COG6 defect nor in patients with other COG defects. This study broadens COG6-CDG genetic landscape and spectrum of malformations.


45) Characterization of VOCs and additives in Italian PET bottles and studies on potential functional aldehydes scavengers

S.Dattilo, C.Gugliuzzo, E.F.Mirabella, C.Puglisi, A.Scamporrino, D.Zampino, F.Samperi

European Food Research and Technology  248  - 2022

DOI: https://doi.org/10.1007/s00217-022-03973-5
This study focused on characterization of Volatile Organic Compounds (VOCs) as contaminants and non-volatile additives in Italian PET bottles, also suggesting potential functional aldehydes scavengers. Several VOCs, such as acetic aldehyde (AA), butanal, 3-methyl butanal, 1,3-dioxolane, pentanal, hexanal, octanal, 5-hepten-2-one, nonanal, and decanal, were identified by Head Space-Gas Chromatography/Mass Spectrometry (HS-GC/MS) in the PET bottles used for the packaging of six Italian brands mineral waters. AA, 1,3-dioxolane, octanal, 5-hepten-2-one, nonanal, and decanal were the most abundant compounds identified. These contaminants were also identified in the PET-bottled mineral waters. Different experiments using bottle-grade PET pellets (Btlg-PET) and PET bottles’ fragments with and without the addition of epoxidized soybean oil (ESBO) or erucamide as lubricant/plasticizer additives, poly(m-xylene adipamide) (MXD6), and/or anthranilamide (2-aminobenzamide) as potential aldehydes scavengers were carried out. Mostly VOCs observed in the PET bottles analysed were identified in a neat ESBO sample. The presence of the ESBO additive in the PET-bottle fragments was also observed by matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis (MALDI?TOF MS). The ESBO sub-products were not observed in the virgin btlg-PET pellets analysed by both HS-GCρMS and MALDI?TOF MS. These results suggest that the VOCs come from an ESBO additive probably loaded during the blow-moulding processes used for the manufacturing of PET bottles. Further studies established that MXD6 (1%w), an efficient oxygen scavenger, could be also used as AA scavenger even in the presence of the commonly used anthranilamide.


46) Impact of nanoparticles on the environmental sustainability of polymer nanocomposites based on bioplastics or recycled plastics - A review of life-cycle assessment studies

S.Carroccio, P.Scarfato, E.Bruno, P.Aprea, N.TzDintcheva, G.Filippone

Journal of Cleaner Production  335,  130322  - 2022

DOI: https://doi.org/10.1016/j.jclepro.2021.130322
Adding nanoparticles to a host polymer can lead to performance improvements that can be twice as beneficial to the environment: first, sustainable nanocomposites based on bioplastics or recycled plastics could replace ubiquitous petroleum-based polymers; second, substantial plastic saving could be achieved by profiting from the superior specific properties of the nanocomposites. Nevertheless, the inherent environmental burden of nanoparticles can compromise the expected benefits. Here we address the controversial issue of the environmental sustainability of "green" polymer nanocomposites based on bioplastics and recycled plastics. A critical review of life-cycle assessment studies regarding nanocomposites and their individual constituents is presented. Nanoparticles have a remarkable environmental impact despite their typically low content. Except for organo-clays and graphene, the production of common nanofillers (nanocellulose, titanium dioxide, silver and, above all, carbon nanotubes) emits relevant amounts of greenhouse gases and requires high energy, nullifying the advantages of using green polymer matrices. Reaching high performance becomes hence crucial to make polymer nanocomposites truly sustainable through material saving. For this purpose, increasing the content of nanoparticles or functionalizing them to enhance their dispersion in the host polymer can unexpectedly entail environmental benefits.

IPCB graphical abstract



47) SLC35A2-CDG: Novel variant and review

D.Quelhas, J.Correia, J.Jaeken, L.Azevedo, M.Lopes-Marques, A.Bandeira, L.Keldermans, G.Matthijs, L.Sturiale. E.Martins

Molecular Genetics and Metabolism Reports  26,  100717  - 2021

DOI: https://doi.org/10.1016/j.ymgmr.2021.100717
SLC35A2 encodes the X-linked transporter that carries uridine diphosphate (UDP)-galactose from the cytosol to the lumen of the Golgi apparatus and the endoplasmic reticulum. Pathogenic variants have been associated to a congenital disorder of glycosylation (CDG) with epileptic encephalopathy as a predominant feature. Among the sixty five patients described so far, a strong gender bias is observed as only seven patients are males. This work is a review and reports a SLC35A2-CDG in a male without epilepsy and with growth deficiency associated with decreased serum IGF1, minor neurological involvement, minor facial dysmorphism, and camptodactyly of fingers and toes. Sequence analysis revealed a hemizygosity for a novel de novo variant: c.233A > G (p.Lys78Arg) in SLC35A2. Further analysis of SLC35A2 sequence by comparing both orthologous and paralogous positions, revealed that not only the variant found in this study, but also most of the reported mutated positions are conserved in SLC35A2 orthologous, and many even in the paralogous SLC35A1 and SLC35A3. This is strong evidence that replacements at these positions will have a critical pathological effect and may also explain the gender bias observed among SLC35A2-CDG patients.


48) Smart nanocomposites of chitosan/alginate nanoparticles loaded with copper oxide as alternative nanofertilizers

M.Leonardi, G.M.Caruso, S.Carroccio, S.Boninelli, G.Curcuruto, M.Zimbone, M.Allegra, B.Torrisi, F.Ferlito, M.Miritello

Environmental Science: Nano  8(1),  174-187  - 2021

DOI: https://doi.org/10.1039/D0EN00797H
In order to best nutrient use efficiency, as required by the increasing food demand for the future global population, in this work an innovative hybrid nanocomposite was designed as an alternative nanoscale fertilizer. An environmentally friendly chemical preparation based on polyelectrolyte complexation was used. A chitosan and sodium alginate complex was selected as a biodegradable shell to release the nanoscale nutrient, CuO nanoparticles. By optimizing the synthesis conditions, i.e. pH and polymer/cross-linker ratio, good stability and accurate size control of the resulting nanocomposites were achieved. The morphology features were evaluated using scanning and transmission electron microscopy, and chemical characterization was performed using X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, dynamic light scattering and inductively coupled plasma optical emission spectrometry. All the collected data confirmed spontaneous polymeric aggregation in nanostructures of sperical shape, having a mean diameter of about 300 nm, as well as CuO encapsulation inside the polymeric coating. Moreover, the role of the biopolymer shell in the significant slowing of copper release from the hybrid nanocomposite was reported. Finally, the nanocomposite efficacy in seeding and germination was evaluated on Fortunella margarita Swingle seeds. The tests demonstrated the benefits in the seedling growth together with a synergic effect in developing both the epigean and hypogean parts. The obtained results indicated that the proposed hybrid nanocomposite could be a potential alternative to realize a smart delivery nanofertilizer using an eco-sustainable method.

IPCB graphical abstract



49) SLC37A4-CDG: Second patient

M.P.Wilson, D.Quelhas, E.Leão-Teles, L.Sturiale, D.Rymen, L.Keldermans, V.Race, E.Souche, E.Rodrigues, T.Campos, E.Van Schaftingen, F.Foulquier, D.Garozzo, G.Matthijs, J.Jaeken

JIMD Reports  58,  122-128  - 2021

DOI: https://doi.org/10.1002/jmd2.12195
Recently, a disorder caused by the heterozygous de novo c.1267C>T (p.R423*) substitution in SLC37A4 has been described. This causes mislocalization of the glucose-6-phosphate transporter to the Golgi leading to a congenital disorder of glycosylation type II (SLC37A4-CDG). Only one patient has been reported showing liver disease that improved with age and mild dysmorphism. Here we report the second patient with a type II CDG caused by the same heterozygous de novo c.1267C>T (p.R423*) mutation thereby confirming the pathogenicity of this variant and expanding the clinical picture with type 1 diabetes, severe scoliosis, and membranoproliferative glomerulonephritis. Additional clinical and biochemical data provide further insight into the mechanism and prognosis of SLC37A4-CDG.


50) HILIC-UPLC-MS for high throughput and isomeric N-glycan separation and characterization in Congenital Disorders Glycosylation and human diseases

A.Messina, A.Palmigiano, F.Esposito, A.Fiumara, A.Bordugo, R.Barone, L.Sturiale, J.Jaeken, D.Garozzo

Glycoconjugate Journal  38(2),  201-211  - 2021

DOI: https://doi.org/10.1007/s10719-020-09947-7
N-glycan analyses may serve uncovering disease-associated biomarkers, as well as for profiling distinctive changes supporting diagnosis of genetic disorders of glycan biosynthesis named congenital disorders of glycosylation (CDG). Strategies based on liquid chromatography (LC) preferentially coupled to electrospray ionization (ESI) - mass spectrometry (MS) have emerged as powerful analytical methods for N-glycan identification and characterization. To enhance detection sensitivity, glycans are commonly labelled with a functional tag prior to LC-MS analysis. Since most derivatization techniques are notoriously time-consuming, some commercial analytical kits have been developed to speed up N-deglycosylation and N-glycan labelling of glycoproteins of pharmaceutical and biological interest such as monoclonal antibodies (mAbs). We exploited the analytical capabilities of RapiFluor-MS (RFMS) to perform, by a slightly modified protocol, a detailed N-glycan characterization of total serum and single serum glycoproteins from specific patients with CDG (MAN1B1-CDG, ALG12-CDG, MOGS-CDG, TMEM199-CDG). This strategy, accomplished by Hydrophilic Interaction Chromatography (HILIC)-UPLC-ESI-MS separation of the RFMS derivatized N-glycans, allowed us to uncover structural details of patients serum released N-glycans, thus extending the current knowledge on glycan profiles in these individual glycosylation diseases. The applied methodology enabled to differentiate in some cases either structural isomers and isomers differing in the linkage type. All the here reported applications demonstrated that RFMS method, coupled to HILIC-UPLC-ESI-MS, represents a sensitive high throughput approach for serum N-glycome analysis and a valuable option for glycan detection and separation particularly for isomeric species.


51) Additive Manufacturing Processing of Plastics for Mass Production of Composites Tooling: Technical and Economic Analysis

G.Cicala, C.Tosto, G.Recca, A.Patti

Macromolecular Symposia  395(1),  2000256  - 2021

DOI: https://doi.org/10.1002/masy.202000256
The present paper focuses on the use of several additive manufacturing (AM) techniques for tooling manufacturing for composite parts production. A geometry that prevents mandrel removal is selected and it is analyzed in a real industrial environment for composites production using autoclave molding. The use of two different AM mandrels is evaluated: fused deposition modeling and liquid crystal display. The results are analyzed in terms of composites part quality, processing time and final part cost.


52) Kinetic Study of the Thermal Dehydration of Fly Ash Filled Geopolymers

I.Blanco, G.Cicala, C.Tosto, G.Recca, G.Dal Poggetto, M.Catauro

Macromolecular Symposia  395(1),  2000225  - 2021

DOI: https://doi.org/10.1002/masy.202000225
Metakaolin-based geopolymers at different percentage of fly ash (namely 25, 50, and 70% wt) are prepared by using recycled fly ash, aiming at reducing the amount of waste to be treated or disposed in landfills. The synthesized samples are subjected to the thermogravimetric analysis (TGA) to investigate the kinetics of dehydration process. To this purpose, TGA data are treated by the Kissinger method to calculate the apparent activation energy (Ea) of dehydration. The obtained kinetics parameters are discussed and compared with each other and with those obtained for the control geopolymer. A decrease in Ea values of the filled geopolymers is found, showing the effect of the fly ash in reducing the dehydration rate. A classification among the samples at different percentage of fly ash is also drawn up, showing the reaching of a plateau at percentage above the 50 wt%.


53) Extraction and characterisation of bioactive proteins from Pongamia pinnata and their conversion into bioproducts for food packaging applications

D.Nataraj, V.Guna, P.Battampara, N.G.Shivashankara, P.Rizzarelli, N.Reddy

Journal of Bioactive and Compatible Polymers   - 2021

DOI: https://doi.org/10.1177/08839115211043280
In this research, proteins were obtained from Pongamia pinnata oil meal and subsequently converted into films and compression molded into various packaging products. Films with a maximum tensile strength of 1.9 MPa were obtained when 15% citric acid was used as the crosslinker. Minimum swelling of 120% was seen in 20% citric acid crosslinked film whereas the uncrosslinked films readily disintegrated in water. The protein films had excellent antioxidant properties with an IC50 value of 14.6 μg/ml compared to 26.9 μg/ml for the standard ascorbic acid. The pongamia protein-based bioproducts showed good activity against Bacillus cereus and Aspergillus niger. Unique properties, low cost, and large availability make pongamia proteins an ideal biopolymer for the development of green and sustainable materials and bioproducts.


54) Clinical and radiological correlates of activities of daily living in cerebellar atrophy caused by PMM2 mutations (PMM2-CDG)

F.Pettinato, G.Mostile, R.Battini, D.Martinelli, A.Madeo, E.Biamino, D.Frattini, D.Garozzo, S.Gasperini, R.Parini, F.Sirchia, G.Sortino, L.Sturiale, G.Matthijs, A.Morrone, M.Di Rocco, R.Rizzo, J.Jaeken, A.Fiumara, R.Barone

Cerebellum  20(4),  596-605  - 2021

DOI: https://www.doi.org/10.1007/s12311-021-01242-x
We aimed to identify clinical, molecular and radiological correlates of activities of daily living (ADL) in patients with cerebellar atrophy caused by PMM2 mutations (PMM2-CDG), the most frequent congenital disorder of glycosylation. Twenty-six PMM2-CDG patients (12 males; mean age 13 ± 11.1 years) underwent a standardized assessment to measure ADL, ataxia (brief ataxia rating scale, BARS) and phenotype severity (Nijmegen CDG rating scale, NCRS). MRI biometry of the cerebellum and the brainstem were performed in 23 patients (11 males; aged 5 months-18 years) and 19 control subjects with equal gender and age distributions. The average total ADL score was 15.3 ± 8.5 (range 3-32 out of 36 indicating severe functional disability), representing variable functional outcome in PMM2-CDG patients. Total ADL scores were significantly correlated with NCRS (r2 = 0.55, p < 0.001) and BARS scores (r2 = 0.764; p < 0.001). Severe intellectual disability, peripheral neuropathy, and severe PMM2 variants were all significantly associated with worse functional outcome. Higher ADL scores were significantly associated with decreased diameters of cerebellar vermis (r2 = 0.347; p = 0.004), hemispheres (r2 = 0.436; p = 0.005), and brainstem, particularly the mid-pons (r2 = 0.64; p < 0.001) representing the major radiological predictor of functional disability score in multivariate regression analysis. We show that cerebellar syndrome severity, cognitive level, peripheral neuropathy, and genotype correlate with ADL used to quantify disease-related deficits in PMM2-CDG. Brainstem involvement should be regarded among functional outcome predictors in patients with cerebellar atrophy caused by PMM2-CDG.


55) EVA Films Loaded with Layered Double Hydroxide (LDH) Modified with Methacrylic Anion: Effect of the Nanohybrid Filler on the Photodegradation Phenomena

G.Gorrasi, G.Viscusi, G.Curcuruto, M.Cantarella, A.Di Mauro, P.Bernardo, G.Clarizia, A.Scamporrino, S.Carroccio

Polymers  13(15),  2525  - 2021

DOI: https://doi.org/10.3390/polym13152525
The photo-oxidative studies of ethylene vinyl acetate copolymer (EVA) matrix, filled with Layered Double Hydroxide (LDH) modified with methacrylic anion (MA), were herein reported, together with gas permeation tests. The formulation of nano-hybrid LDHs was characterized using X-ray diffractometry (XRD) and thermogravimetric analysis (TGA), demonstrating the partial intercalation of the 30% of MA anion between the LDH’s galleries. The as-modified filler was introduced into an EVA matrix by mechanical milling, producing free-standing films subjected to accelerated aging. Fourier transform infrared spectroscopy (FT-IR) results suggested that the nanohybrid presence determined a stabilizing effect up to 45 days of UV irradiation, especially if compared to the EVA/LDH references for all formulated EVA hybrid nanocomposites. Conversely, the presence of nanohybrid in the matrix did not significantly change the thermal stability of EVA samples. The dispersion of modified MA-LDH in the EVA matrix produces defect-free samples in the whole range of investigated loadings. The samples show a slight decrease in gas permeability, coupled with a substantial stabilization of the original CO2/O2 selectivity, which also proves the integrity of the films after 30 days of UV irradiation.

IPCB graphical abstract



56) N-Glycomics of Human Erythrocytes

R.O.Bua, A.Messina, L.Sturiale, R.Barone, D.Garozzo, A.Palmigiano

International Journal of Molecular Sciences  22(15),  8063  - 2021

DOI: https://doi.org/10.3390/ijms22158063
Glycosylation is a complex post-translational modification that conveys functional diversity to glycoconjugates. Cell surface glycosylation mediates several biological activities such as induction of the intracellular signaling pathway and pathogen recognition. Red blood cell (RBC) membrane N-glycans determine blood type and influence cell lifespan. Although several proteomic studies have been carried out, the glycosylation of RBC membrane proteins has not been systematically investigated. This work aims at exploring the human RBC N-glycome by high-sensitivity MALDI-MS techniques to outline a fingerprint of RBC N-glycans. To this purpose, the MALDI-TOF spectra of healthy subjects harboring different blood groups were acquired. Results showed the predominant occurrence of neutral and sialylated complex N-glycans with bisected N-acetylglucosamine and core- and/or antennary fucosylation. In the higher mass region, these species presented with multiple N-acetyllactosamine repeating units. Amongst the detected glycoforms, the presence of glycans bearing ABO(H) antigens allowed us to define a distinctive spectrum for each blood group. For the first time, advanced glycomic techniques have been applied to a comprehensive exploration of human RBC N-glycosylation, providing a new tool for the early detection of distinct glycome changes associated with disease conditions as well as for understanding the molecular recognition of pathogens.


57) Clinical, molecular and glycophenotype insights in SLC39A8-CDG

E.Bonaventura, R.Barone, L.Sturiale, R.Pasquariello, M.G.Alessandrì, A.M.Pinto, A.Renieri, C.Panteghini, B.Garavaglia, G.Cioni, R.Battini

Orphanet Journal of Rare Diseases  16(1),  307  - 2021

DOI: https://www.doi.org/10.1186/s13023-021-01941-y
Background
SLC39A8, a gene located on chromosome 4q24, encodes for the manganese (Mn) transporter ZIP8 and its detrimental variants cause a type 2 congenital disorder of glycosylation (CDG). The common SLC39A8 missense variant A391T is associated with increased risk for multiple neurological and systemic disorders and with decreased serum Mn. Patients with SLC39A8-CDG present with different clinical and neuroradiological features linked to variable transferrin glycosylation profile. Galactose and Mn supplementation therapy results in the biochemical and clinical amelioration of treated patients.
Results
Here, we report clinical manifestations, neuroradiological features and glycophenotypes associated with novel SLC39A8 variants (c.1048G > A; p.Gly350Arg and c.131C > G; p.Ser44Trp) in two siblings of the same Italian family. Furthermore, we describe a third patient with overlapping clinical features harbouring the homozygous missense variant A391T. The clinical phenotype of the three patients was characterized by severe developmental disability, dystonic postural pattern and dyskinesia with a more severe progression of the disease in the two affected siblings. Neuroimaging showed a Leigh syndrome-like pattern involving the basal ganglia, thalami and white matter. In the two siblings, atrophic cerebral and cerebellum changes consistent with SLC39A8-CDG were detected as well. Serum transferrin isoelectric focusing (IEF) yielded variable results with slight increase of trisialotransferrin isoforms or even normal pattern. MALDI-MS showed the presence of hypogalactosylated transferrin N-glycans, spontaneously decreasing during the disease course, only in one affected sibling. Total serum N-glycome depicted a distinct pattern for the three patients, with increased levels of undergalactosylated and undersialylated precursors of fully sialylated biantennary glycans, including the monosialo-monogalacto-biantennary species A2G1S1.
Conclusions
Clinical, MRI and glycosylation features of patients are consistent with SLC39A8-CDG. We document two novel variants associated with Leigh syndrome-like disease presentation of SLC39A8-CDG. We show, for the first time, a severe neurological phenotype overlapping with that described for SLC39A8-CDG in association with the homozygous A391T missense variant. We observed a spontaneous amelioration of transferrin N-glycome, highlighting the efficacy of MS-based serum glycomics as auxiliary tool for the diagnosis and clinical management of therapy response in patients with SLC39A8-CDG. Further studies are needed to analyse more in depth the influence of SLC39A8 variants, including the common missense variant, on the expression and function of ZIP8 protein, and their impact on clinical, biochemical and neuroradiological features.


58) Properties and Applications of Nanoparticles from Plant Proteins

N.Reddy, M.Rapisarda

Materials  14(13),  3607  - 2021

DOI: https://doi.org/10.3390/ma14133607
Nanoparticles from plant proteins are preferred over carbohydrates and synthetic polymeric-based materials for food, medical and other applications. In addition to their large availability and relatively low cost, plant proteins offer higher possibilities for surface modifications and functionalizing various biomolecules for specific applications. Plant proteins also avoid the immunogenic responses associated with the use of animal proteins. However, the sources of plant proteins are very diverse, and proteins from each source have distinct structures, properties and processing requirements. While proteins from corn (zein) and wheat (gliadin) are soluble in aqueous ethanol, most other plant proteins are insoluble in aqueous conditions. Apart from zein and gliadin nanoparticles (which are relatively easy to prepare), soy proteins, wheat glutenin and proteins from several legumes have been made into nanoparticles. The extraction of soluble proteins, hydrolyzing with alkali and acids, conjugation with other biopolymers, and newer techniques such as microfluidization and electrospraying have been adopted to develop plant protein nanoparticles. Solid, hollow, and core-shell nanoparticles with varying sizes and physical and chemical properties have been developed. Most plant protein nanoparticles have been used as carriers for drugs and as biomolecules for controlled release applications and for stabilizing food emulsions. This review provides an overview of the approaches used to prepare nanoparticles from plant proteins, and their properties and potential applications. The review’s specific focus is on the preparation methods and applications, rather than the properties of the proteins, which have been reported in detail in other publications.

IPCB graphical abstract



59) Synthesis and UV-light induced oligomerization of a benzofulvene-based neutral platinum(II) complex

M.Paolino, A.Reale, G.Magrini, V.Razzano, M.Saletti, G.Giuliani, A.Donati, F.Samperi, A.Scamporrino, M.Canetti, M.Mauro, F.Villafiorita-Monteleone, E.Foise, C.Botta, A.Cappelli

European Polymer Journal  165,  110597  - 2021

DOI: https://doi.org/10.1016/j.eurpolymj.2021.110597
Neutral platinum(II) complex 2-PTPC-BF3a was easily prepared from benzofulvene derivative 2-Pyr-BF3a in order to evaluate the effects in the aggregation/polymerization behavior of a bulky substituent capable of establishing intermolecular metal-metal interactions in the close proximity of the putative polymerization center. Complex 2-PTPC-BF3a was found to aggregate into an ordered crystalline solid-state without significant spontaneous polymerization, but the UV-light irradiation of its dispersions in chloroform produced corresponding oligomers, which were characterized by NMR spectroscopy and MALDI-TOF mass spectrometry. On the other hand, the UV-irradiation of the platinum complex in the solid-state produced different results probably depending on the aggregate architecture. Notably, the crystalline films deposited from THF solutions on quartz substrates showed weak emissions, which progressively increased upon irradiation with the formation of oligomers devoid of the aggregation-induced quenching sites that seemed to affect the emission of poly-2-PTPC-BF3a. Finally, DFT calculations were performed on platinum complex 2-PTPC-BF3a in the aim of rationalizing the observed photophysical features.

IPCB graphical abstract



60) Influence of photo-oxidation on the performance and soil degradation of oxo- and biodegradable polymer-based items for agricultural applications

P.Rizzarelli, M.Rapisarda, L.Ascione, F.Degli Innocenti, F.P.La Mantia

Polymer Degradation and Stability  188  - 2021

DOI: https://doi.org/10.1016/j.polymdegradstab.2021.109578
The examination of the aging behavior of polymers, blends, composites, items, etc. under different environmental conditions is a priority issue for assessing the possible applications and establishing the lifetime. In agriculture, plastic items (mulch films, irrigation tubes, etc.) are widely used and subjected to solar UV exposure that can induce photo-oxidation on macromolecular chains. Therefore, weathering under outdoor conditions and accelerated degradation tests are performed for simulating aging processes during the lifetime of materials and select appropriate stabilizers to be used. In the last decades, oxo- and biodegradable polymers have been investigated and used in agricultural items. The influence of photooxidation or outdoor weathering on their structures, performance and biodegradation behavior in soil has been evaluated. This review aims to provide an overview of the studies focused on the effects of photo-degradation processes on chemical-physical properties and degradation in soil of oxo- and biodegradable polymers or items designed for agricultural purpose, including an outline of the available standards. Additionally, a comparison between the behaviors induced by photo-oxidation of the two different families of degradable polymers used in agricultural plastic items is carried out.


61) Lipopolysaccharide from Gut-Associated Lymphoid-Tissue-Resident Alcaligenes faecalis: Complete Structure Determination and Chemical Synthesis of Its Lipid A

A.Shimoyama, F.Di Lorenzo, H.Yamaura, K.Mizote, A.Palmigiano, M.Pither, I.Speciale, T.Uto, S.Masui, L.Sturiale, D.Garozzo, K.Hosomi, N.Shibata, K.Kabayama, Y.Fujimoto, A.Silipo, J.Kunisawa, H.Kiyono, A.Molinaro, K.Fukase

Angewandte Chemie  60(18),  10023-10031  - 2021

DOI: https://doi.org/10.1002/ange.202012374
Alcaligenes faecalis is the predominant Gram-negative bacterium inhabiting gut-associated lymphoid tissues, Peyer’s patches. We previously reported that an A. faecalis lipopolysaccharide (LPS) acted as a weak agonist for Toll-like receptor 4 (TLR4)/myeloid differentiation factor-2 (MD-2) receptor as well as a potent inducer of IgA without excessive inflammation, thus suggesting that A. faecalis LPS might be used as a safe adjuvant. In this study, we characterized the structure of both the lipooligosaccharide (LOS) and LPS from A. faecalis. We synthesized three lipid A molecules with different degrees of acylation by an efficient route involving the simultaneous introduction of 1- and 4’-phosphates. Hexaacylated A. faecalis lipid A showed moderate agonistic activity towards TLR4-mediated signaling and the ability to elicit a discrete interleukin-6 release in human cell lines and mice. It was thus found to be the active principle of the LOS/LPS and a promising vaccine adjuvant candidate.

IPCB graphical abstract



62) Mass spectrometry glycophenotype characterization of ALG2-CDG in Argentinean patients with a new genetic variant in homozygosis

G.Magali Papazoglu, M.Cubilla, M.Pereyra, R.Dodelson de Kremer, B.Pérez, L.Sturiale, C.G.Asteggiano

Glycoconjugate Journal  38,  191-200  - 2021

DOI: https://doi.org/10.1007/s10719-021-09976-w
Human ALG2 encodes an α 1,3mannosyltransferase that catalyzes the first steps in the synthesis of N-glycans in the endoplasmic reticulum. Variants in ALG2 cause a congenital disorder of glycosylation (CDG) known as ALG2-CDG. Up to date, nine ALG2-CDG patients have been reported worldwide. ALG2-CDG is a rare autosomal recessive inherited disorder characterized by neurological involvement, convulsive syndrome of unknown origin, axial hypotonia, and mental and motor regression. In this study, we used MALDI-TOF MS to define both total serum protein and transferrin (Tf) N-glycan phenotypes in three ALG2-CDG patients carrying a c.752G > T, p.Arg251Leu ALG2 missense variant in homozygous state, as determined by exome sequencing. Comparing it to control samples, we have observed Tf under-occupancy of glycosylation site(s) typical of a defective N-glycan assembly and the occurrence of oligomannose and hybrid type N-glycans. Moreover, we have observed a slight oligomannose accumulation in total serum glyco-profiles. The increased heterogeneity of serum N-glycome in the studied patients suggests a marginal disarrangement of the glycan processing in ALG2-CDG. Previous studies reported on slightly increased concentrations of abnormal serum N-glycans in CDG-I due to defects in the mannosylation steps of dolichol-linked oligosaccharide biosynthesis. This preliminary work aims at considering serum N-glycan accumulation of high mannosylated glycoforms, such as oligomannose and hybrid type N-glycans, as potential diagnostic signals for ALG2-CDG patients.


63) Innovative Polymeric Hybrid Nanocomposites for Application in Photocatalysis

M.Cantarella, G.Impellizzeri, A.Di Mauro, V.Privitera, S.Carroccio

Polymers  13(8),  1184  - 2021

DOI: https://doi.org/10.3390/polym13081184
The immobilization of inorganic nanomaterials on polymeric substrates has been drawing a lot of attention in recent years owing to the extraordinary properties of the as-obtained materials. The hybrid materials, indeed, combine the benefits of the plastic matter such as flexibility, low-cost, mechanical stability and high durability, with them deriving from their inorganic counterparts. In particular, if the inorganic fillers are nanostructured photocatalysts, the originated hybrid systems will be able to utilize the energy delivered by light, catalysing chemical reactions in a sustainable pathway. Most importantly, since the nanofillers can be ad-hoc anchored to the macromolecular structure, their release in the environment will be prevented, thus overcoming one of the main restrictions that impedes their applications on a large scale. In this review, several typologies of hybrid photocatalytic nanomaterials, obtained by using both organic and inorganic semiconductors and realized with different synthetic protocols, were reported and discussed. In the first part of the manuscript, nanocomposites realized by simply blending the TiO2 or ZnO nanomaterials in thermoplastic polymeric matrices are illustrated. Subsequently, the atomic layer deposition (ALD) technique is presented as an excellent method to formulate polymeric nanocomposites. Successively, some examples of polyporphyrins hybrid systems containing graphene, acting as photocatalysts under visible light irradiation, are discussed. Lastly, photocatalytic polymeric nanosponges, with extraordinary adsorption properties, are shown. All the described materials were deeply characterized and their photocatalytic abilities were evaluated by the degradation of several organic water pollutants such as dyes, phenol, pesticides, drugs, and personal care products. The antibacterial performance was also evaluated for selected systems. The relevance of the obtained results is widely overviewed, opening the route for the application of such multifunctional photocatalytic hybrid materials in wastewater remediation.

IPCB graphical abstract



64) Aberrant sialylation in a patient with a HNF1α variant and liver adenomatosis

L.Sturiale, M.C.Nassogne, A.Palmigiano, A.Messina, I.Speciale, R.Artuso, G.Bertino, N.Revencu, X.Stephénne, C.De Castro, G.Matthijs, R.Barone, J.Jaeken, D.Garozzo

iScience  24(4),  102323  - 2021

DOI: https://doi.org/10.1016/j.isci.2021.102323
Glycosylation is a fundamental post-translational modification of proteins that boosts their structural diversity providing subtle and specialized biological properties and functions. All those genetic diseases due to a defective glycan biosynthesis and attachment to the nascent glycoproteins fall within the wide area of congenital disorders of glycosylation (CDG), mostly causing multisystem involvement. In the present paper, we detailed the unique serum N-glycosylation of a CDG-candidate patient with an unexplained neurological phenotype and liver adenomatosis harboring a recurrent pathogenic HNF1α variant. Serum transferrin isoelectric focusing showed a surprising N-glycosylation pattern consisting on hyposialylation, as well as remarkable hypersialylation. Mass spectrometry-based glycomic analyses of individual serum glycoproteins enabled to unveil hypersialylated complex N-glycans comprising up to two sialic acids per antenna. Further advanced MS analysis showed the additional sialic acid is bonded through an α2-6 linkage to the peripheral N-acetylglucosamine residue.

IPCB graphical abstract



65) Mechanical, Wear and Thermal Behavior of Polyethylene Blended with Graphite Treated in Ball Milling

A.Visco, A.Grasso, G.Recca, D.Carbone, A.Pistone

Polymers  13(6),  975  - 2021

DOI: https://doi.org/10.3390/polym13060975
Additive manufacturing, civil, and biomechanical applications are among the most important sectors, where the filler’s presence can significantly improve the quality of polymeric products blends. The high market demand of new low-cost material to be used as shock absorbers and mechanical joints arouses our curiosity to study a relatively common commercial polymer and filler. The possible improvement by blending high-density polyethylene (HDPE) and graphite was investigated for these sectors. To achieve this objective, we have prepared HDPE/graphite nanocomposites following mechanical treatment to understand which parameter provides the researched properties. As widely reported in the literature, milling treatment leads to the decrease of the particle size and the exfoliation of graphitic layers. Therefore, graphite has been previously treated with a ball mill for different times (1-16 h) to enhance its lubricating action. We checked an improvement in stiffness, yielding strength, thermal stability, and, in particularly, wear resistance that increased by 65% with respect to that of polyethylene (PE). A treatment time of eight hours in ball milling could be enough to give an appreciable improvement. The wear behavior of HDPE with treated graphite has not been deeply investigated so far, and it could be important because HDPE is considered a "carrier polymer" for different low-friction applications.


66) Mechanical Properties of Protective Coatings against Marine Fouling: A Review

A.Pistone, C.Scolaro, A.Visco

Polymers  13(2),  173  - 2021

DOI: https://doi.org/10.3390/polym13020173
The accumulation of marine organisms on ship hulls, such as microorganisms, barnacles, and seaweeds, represents a global problem for maritime industries, with both economic and environmental costs. The use of biocide-containing paints poses a serious threat to marine ecosystems, affecting both target and non-target organisms driving science and technology towards non-biocidal solutions based on physico-chemical and materials properties of coatings. The review reports recent development of hydrophobic protective coatings in terms of mechanical properties, correlated with the wet ability features. The attention is focused mainly on coatings based on siloxane and epoxy resin due to the wide application fields of such systems in the marine industry. Polyurethane and other systems have been considered as well. These coatings for anti-fouling applications needs to be both long-term mechanically stable, perfectly adherent with the metallic/composite substrate, and capable to detach/destroy the fouling organism. Prospects should focus on developing even "greener" antifouling coatings solutions. These coatings should also be readily addressable to industrial scale-up for large-scale product distribution, possibly at a reasonable cost.


67) Mechanical Characterization of Nanocomposite Joints Based on Biomedical Grade Polyethylene under Cyclical Loads

A.Visco, C.Scolaro, A.Quattrocchi, R.Montanini

Polymers  12(11),  2681  - 2021

DOI: https://doi.org/10.3390/polym12112681
Polymeric joints, made of biomedical polyethylene (UHMWPE) nanocomposite sheets, were welded with a diode laser. Since polyethylene does not absorb laser light, nanocomposites were prepared containing different percentages by weight of titanium dioxide as it is a laser absorbent. The joints were first analyzed with static mechanical tests to establish the best percentage weight content of filler that had the best mechanical response. Then, the nanocomposites containing 1 wt% titanium dioxide were selected (white color) to be subjected to fatigue tests. The experimental results were also compared with those obtained on UMMWPE with a different laser light absorbent nano filler (carbon, with greater laser absorbing power, gray in color), already studied by our research team. The results showed that the two types of joints had an appreciable resistance to fatigue, depending on the various loads imposed. Therefore, they can be chosen in different applications of UHMWPE, depending on the stresses imposed during their use.

IPCB graphical abstract



68) Polyurethane Foams Loaded with Carbon Nanofibers for Oil Spill Recovery: Mechanical Properties under Fatigue Conditions and Selective Absorption in Oil/Water Mixtures

A.Visco, A.Quattrocchi, D.Nocita, R.Montanini, A.Pistone

Nanomaterials  11(3),  735  - 2021

DOI: https://doi.org/10.3390/nano11030735
Marine pollution due to spillage of hydrocarbons represents a well-known current environmental problem. In order to recover the otherwise wasted oils and to prevent pollution damage, polyurethane foams are considered suitable materials for their ability to separate oils from sea-water and for their reusability. In this work we studied polyurethane foams filled with carbon nanofibers, in varying amounts, aimed at enhancing the selectivity of the material towards the oils and at improving the mechanical durability of the foam. Polyurethane-based foams were experimentally characterized by morphological, surface, and mechanical analyses (optical microscopy observation, contact angle measurement, absorption test according to ASTM F726-99 standard and compression fatigue tests according to ISO 24999 standard). Results indicated an increase in hydrophobic behavior and a good oleophilic character of the composite sponges besides an improved selective absorption of the foam toward oils in mixed water/oil media. The optimal filler amount was found to be around 1 wt% for the homogeneous distribution inside the polymeric foam. Finally, the fatigue test results showed an improvement of the mechanical properties of the foam with the growing carbon filler amount.

IPCB graphical abstract



69) Tear N-glycomics in vernal and atopic keratoconjunctivitis

A.Messina, A.Palmigiano, C.Tosto, D.Romeo, L.Sturiale, D.Garozzo, A.Leonardi

Allergy  76(8),  2500-2509  - 2021

DOI: https://doi.org/10.1111/all.14775
Purpose: Tear fluid N-Glycome from patients affected with vernal (VKC) and atopic keratoconjunctivitis (AKC) was investigated to identify specific changes in tears and to recognize possible glyco-biomarkers.
Methods: The analysis of the N-glycans was performed using matrix-assisted laser desorption ionization mass spectrometry on single tear samples. Tears from control normal subjects (CTRL), VKC and AKC patients were processed and treated with peptide N-glycosidase F (PNGase F) to deglycosylate N-glycoproteins. Released N-glycans were purified, permethylated, and analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and tandem mass spectrometry (MALDI-TOF MS and MALDI-TOF MS/MS).
Results: More than 150 complex N-glycans, including highly fucosylated biantennary, triantennary, tetra-antennary, and bisecting species, were observed in our spectra. Three distinct patterns for CTRL, VKC, and AKC patients were identified in terms of relative intensities for some N-glycans structures. Major variations involved bisecting and hyperfucosylated glycoforms.
The most intense ions were associated with species at m/z 1907.0 (asialo, agalacto, bisected, biantennary structure-NGA2B) in CTRL MS profiles, at m/z 2605.3 and 2966.5 in VKC, and at m/z 2792.4 in AKC corresponding to a well-known biantennary, disialylated N-glycan. Several peaks were associated with structures bearing one or two Lewis X epitopes. Structures were confirmed by MS/MS analysis. Quantitative differences among the three groups were statistically significant.
Conclusions: Tear MS profiles are rich in specific glycoforms, particularly those with a high fucosylation degree, indicating both core and peripheral decoration. Tear N-glycome analysis provided important information for a better comprehension of VKC and AKC alterations at the molecular level.

IPCB graphical abstract



70) Thermo-mechanical, antimicrobial and biocompatible properties of PVC blends based on imidazolium ionic liquids

D.Zampino, M.Mancuso, R.Zaccone, T.Ferreri, A.Borzacchiello, S.Zeppetelli, S.Dattilo, M.Ussia, L.Ferreri, D.Carbone, G.Recca, C.Puglisi

Materials Science and Engineering: C  122,  111920  - 2021

DOI: https://doi.org/10.1016/j.msec.2021.111920
The aim of this study was the development of antimicrobial polyvinylchloride (PVC) blends loaded with 0.1-10% (w/w) of the ILs 1-hexadecyl-3-methylimidazolium 1,3-dimethyl 5-sulfoisophthalate (HdmimDMSIP) and 1-octyloximethyl-3-methylimidazolium hexafluorophosphate (OOMmimPF6). The synthetized ILs were characterized by 1HNMR, MALDI-TOF, DSC and TGA. PVC/ILs films were obtained by solvent casting.Thermal and mechanical properties (tensile stress TS and elongation at break EB), morphology by SEM, surface wettability, antimicrobial activity, cytotoxicity and ILs release in sterile water from PVC/ILs film blends were determined. Results demonstrated that the presence of both ILs in PVC formulation slightly affected thermal and mechanical properties of blends. The loading of both ILs into PVC matrix made PVC/ILs films hydrophilic, especially at the highest concentration of HdmimDMSIP. The PVC/ILs blends displayed antibacterial activity up to ILs lowest concentrations (0.1-0.5%). The inhibition of Escherichia coli growth was lower than that showed toward Staphylococcus epidermidis. The addition of 10% ILs concentration resulted excessive as demonstrated by accumulation of ILs on film surfaces (SEM) and ILs high release from PVC/ILs blends during the first day of water immersion. Biocompatibility studies highlighted that the addition of low amounts of both ILs into PVC matrix is not cytotoxic for mouse fibroblast cells (L929), supporting their potential use for biomedical porposes.


71) 3D-Printed micro-optofluidic device for chemical fluids and cells detection

F.Cairone, S.Davi, G.Stella, F.Guarino, G.Recca, G.Cicala, M.Bucolo

Biomedical Microdevices  22  - 2020

DOI: https://doi.org/10.1007/s10544-020-00487-3
In this work, it is presented a micro-optofluidic flow detector used for on-chip biological and chemical samples investigation. It is made in Poly-dimethyl-siloxane using a master-slave approach based on the 3D-Printing techniques. The micro-optofluidic device is made by assembling a microfluidic T-junction with a micro-optical section that consists of two optical fiber insertions and a PDMS gold-spattered micro-waveguide. The working principle in the detection is based on a different light transmission correlated to the fluid interfering with the laser beam in a micro-channel section. The proposed solution allows to realize a PDMS micro-device taking the advantage of 3D-Printing and goes beyond the restriction in the material selection. The device?s performances were tested in the fluids detection and in the evaluation of the cell concentrations. Additionally, the micro-device was used as a real-time two-phase fluids flow detector. The two-phases flows were successfully monitored in different experimental conditions, varying both hydrodynamic and optical external stimuli.


72) Influence of the Processing Conditions on the Mechanical Performance of Sustainable Bio-Based PLA Compounds

A.Patti, D.Acierno, A.Latteri, C.Tosto, E.Pergolizzi, G.Recca, M.Cristaudo, G.Cicala

Polymers  12(10),  2197  - 2020

DOI: https://doi.org/10.3390/polym12102197
Cellulose/PLA-based blends (up to 77 vol./vol.% of the added fibers) for applications in extrusion-based technology were realized in an internal mixer by setting different operating conditions. In particular, both the mixing time and temperature were increased in order to simulate a recycling operation (10 or 25 min, 170 or 190 °C) and gain information on the potential reuse of the developed systems. The torque measurements during the compound?s preparation, and the compound?s mechanical tensile features, both in the static and dynamic mode, were evaluated for each investigated composition. The final results confirmed a reduction of the torque trend over time for the PLA matrix, which was attributed to a possible degradation mechanism, and confirmed by infrared spectroscopy. The mechanical behaviour of the pristine polymer changed from elastoplastic to brittle, with a significant loss in ductility going from the lower mixing temperatures up to the higher ones for the longest time. Through the addition of cellulose fibers into the composite systems, a higher stabilization of the torque in the time and an improvement in the mechanical performance were always verified compared to the neat PLA, with a maximum increase in the Young modulus (+100%) and the tensile strength (+57%), and a partial recovery of the ductility.

IPCB graphical abstract



73) Novel pranoprofen-poly(ε-caprolactone) conjugates: microwave-assisted synthesis and structural characterization

G.Impallomeni, P.G.Mineo, F.Vento, A.Ballistreri

Polymer International   - 2020

DOI: https://doi.org/10.1002/pi.6141
Biodegradable polymers are used in many biomedical devices, such as implants, cellular scaffolds and drug delivery systems. To improve drug delivery capability and to reduce systemic toxicity, the interest in polymer-drug conjugates has increased remarkably. With this aim, pranoprofen (PPF) (an effective non-steroidal anti-inflammatory drug used mainly in ophthalmology) was conjugated to poly(ε-caprolactone) (PCL) via microwave-assisted transesterification, acid-catalyzed by p-toluenesulfonic acid. The products obtained were characterized by NMR, matrix assisted laser desorption ionization time of flight mass spectrometry, gel permeation chromatography (which gave proof of the covalent link between PPF and PCL) and thermal analyses. The conjugates were found to contain up to 4.3% w/w of PPF and had molecular weights ranging from 5 to 12 kDa.


74) Development and biocompatibility assessments of poly(3-hydroxybutyrate-co-ε-caprolactone) microparticles for diclofenac sodium delivery

T.Musumeci, A.Bonaccorso, C.Carbone, G.Impallomeni, A.Ballistreri, J.Th.Duskey, G.Puglisi, R.Pignatello

Journal of Drug Delivery Science and Technology  60,  102081  - 2020

DOI: https://doi.org/10.1016/j.jddst.2020.102081
Osteoarthritis (OA) is a debilitating disease affecting joints and impairing the ability to perform everyday tasks. Current treatment regimens tend to provide little to no relief. Therefore, there is a huge need for alternative strategies to manage this painful condition. The delivery of anti-inflammatory drugs into an injured joint with the aim of eliminating articular inflammation and modulate cartilage damage could be a useful strategy to treat OA. Accordingly, the aim of this study is to prepare microparticles (MPs) from new biodegradable poly (3-hydroxybutyrate-co-ε-caprolactone) copolymers (PHBCL) for the potential intra-articular injection of Diclofenac sodium for OA treatment. MPs were prepared starting from copolymers having different molecular weights and an HB/CL molar ratio and studied for their morphologies and size distribution by scanning electron microscopy. Drug loading and encapsulation efficiency were also determined. The in vitro release profile was assessed by the dialysis bag technique and the kinetic profile was evaluated by using several mathematical models revealing a diffusion release mechanism. A1 polymer and related MPs, as representative of the group, were selected for further biological investigation. In vitro studies performed on CaCo-2 and Balb/3T3 cells showed no toxic effects at the desired concentrations as revealed by MTT, CFE and Comet assays.

IPCB graphical abstract



75) Chlorovirus PBCV-1 protein A064R has three of the transferase activities necessary to synthesize its capsid protein N-linked glycans

I.Speciale, M.Laugieri, E.Noel, S.Lin, T.Lowary, A.Molinaro, G.Duncan, I.Agarkova, D.Garozzo, M.Tonetti, J.Van Etten, C.De Castro

Proceedings of the National Academy of Sciences of The United States of America   - 2020

DOI: https://doi.org/10.1073/pnas.2016626117
The chloroviruses are unusual because they are predicted to encode most, if not all, of the machinery to synthesize the glycans attached to their major capsid proteins. Here we show that two of the virus-encoded proteins A064R and A061L are functionally active. A064R has three domains: The first two are GTs and the third domain is a methyltransferase. A061L has a methyltransferase activity. The action of these two enzymes produce the fragment 2,3-di-O-methyl-α-L-Rha-(1→ 2)-β-L-Rha, which is part of the complex N-linked glycan attached to the virus capsid protein. A064R domain 2 is a member of a new GT family. This provides direct evidence that the synthesis of PBCV-1 glycans are accomplished with virus-encoded enzymes.


76) Structure of the unusual Sinorhizobium fredii HH103 lipopolysaccharide and its role in symbiosis

F.Di Lorenzo, I.Speciale, A.Silipo, C.Alías-Villegas, S.Acosta-Jurado, M.Rodríguez-Carvajal, M.Dardanelli, A.Palmigiano, D.Garozzo, J.Ruiz-Sainz, A.Molinaro, J.Vinardell

Journal of Biological Chemistry  295 (32),  10969-10987  - 2020

DOI: https://doi.org/10.1074/jbc.RA120.013393
Rhizobia are soil bacteria that form important symbiotic associations with legumes, and rhizobial surface polysaccharides, such as K-antigen polysaccharide (KPS) and lipopolysaccharide (LPS), might be important for symbiosis. Previously, we obtained a mutant of Sinorhizobium fredii HH103, rkpA, that does not produce KPS, a homopolysaccharide of a pseudaminic acid derivative, but whose LPS electrophoretic profile was indistinguishable from that of the WT strain. We also previously demonstrated that the HH103 rkpLMNOPQ operon is responsible for 5-acetamido-3,5,7,9-tetradeoxy-7-(3-hydroxybutyramido)-L-glycero-L-manno-nonulosonic acid [Pse5NAc7(3OHBu)] production and is involved in HH103 KPS and LPS biosynthesis and that an HH103 rkpM mutant cannot produce KPS and displays an altered LPS structure. Here, we analyzed the LPS structure of HH103 rkpA, focusing on the carbohydrate portion, and found that it contains a highly heterogeneous lipid A and a peculiar core oligosaccharide composed of an unusually high number of hexuronic acids containing β-configured Pse5NAc7(3OHBu). This pseudaminic acid derivative, in its α-configuration, was the only structural component of the S. fredii HH103 KPS and, to the best of our knowledge, has never been reported from any other rhizobial LPS. We also show that Pse5NAc7(3OHBu) is the complete or partial epitope for a mAb, NB6-228.22, that can recognize the HH103 LPS, but not those of most of the S. fredii strains tested here. We also show that the LPS from HH103 rkpM is identical to that of HH103 rkpA but devoid of any Pse5NAc7(3OHBu) residues. Notably, this rkpM mutant was severely impaired in symbiosis with its host, Macroptilium atropurpureum.


77) Properties of Biodegradable Films Based on Poly(butylene Succinate) (PBS) and Poly(butylene Adipate-co-Terephthalate) (PBAT) Blends

A.R. de Matos Costa, A.Crocitti, L.Hecker de Hecker de Carvalho, S.Carroccio, P.Cerruti, G.Santagata

Polymers  12(10),  2317  - 2020

DOI: https://doi.org/10.3390/polym12102317
Compression molded biodegradable films based on poly(butylene succinate) (PBS) and poly(butylene adipate-co-terephthalate) (PBAT) at varying weights were prepared, and their relevant properties for packaging applications are here reported. The melt rheology of the blends was first studied, and the binary PBS/PBAT blends exhibited marked shear thinning and complex thermoreological behavior, due to the formation of a co-continuous morphology in the 50 wt% blend. The films were characterized by infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), mechanical tensile tests, scanning electron microscopy (SEM), and oxygen and water vapor permeability. PBS crystallization was inhibited in the blends with higher contents of PBAT, and FTIR and SEM analysis suggested that limited interactions occur between the two polymer phases. The films showed increasing stiffness as the PBS percentage increased; further, a sharp decrease in elongation at break was noticed for the films containing percentages of PBS greater than 25 wt%. Gas permeability decreased with increasing PBS content, indicating that the barrier properties of PBS can be tuned by blending with PBAT. The results obtained point out that the blend containing 25 wt% PBS is a good compromise between elastic modulus (135 MPa) and deformation at break (390%) values. Overall, PBS/PBAT blends represent an alternative for packaging films, as they combine biodegradability, good barrier properties and reasonable mechanical behavior.

IPCB graphical abstract



78) UV-light-induced polymerization in the amorphous solid-state of a spontaneously non-polymerizing 3-phenylbenzofulvene monomer

M.Paolino, A.Reale, G.Magrini, V.Razzano, G.Giuliani, A.Donati, G.Giorgi, F.Samperi, M.Canetti, M.Mauro, F.Villafiorita-Monteleone, E.Fois, C.Botta, A.Cappelli

European Polymer Journal  137,  109923  - 2020

DOI: https://doi.org/10.1016/j.eurpolymj.2020.109923
Benzofulvene derivative 2-Pyr-BF3a was designed and synthesized to evaluate the effects of a pyridine ring in position 2 of the 3-phenylbenzofulvene moiety on the spontaneous solid-state polymerization. The monomer was found to organize into an ordered crystalline solid-state without significant spontaneous polymerization, but the irradiation of amorphous film samples with UV-light produced photopolymerization. Resulting poly-2-Pyr-BF3a was characterized by NMR spectroscopy, MALDI-TOF mass spectrometry, and photophysical studies in comparison with the corresponding monomer. Interestingly, monomer 2-Pyr-BF3a was weakly emissive in diluted solutions, but increased its PLQY in the crystalline solid. Conversely, after photopolymerization the monomeric unit in the polymer enhanced its emission intensity in solution while in the solid state results weakly emissive. Even more interestingly, this benzofulvene monomer and its synthetic precursors 2 and 3 showed long-lived emission suggesting a phosphorescence nature of the emission process. Finally, DFT and TDDFT calculations were performed in order to rationalize the experimental data.

IPCB graphical abstract



79) Preparation, characterization, and antimicrobial activity of ferrocene-containing polymeric materials

D.Zampino, S.Pedotti, M.Ussia, S.Dattilo, M.Mancuso, R.Zaccone, A.Patti

Journal of Applied Polymer Science   - 2020

DOI: https://doi.org/10.1002/app.49852
Ferrocenyl(benzyl) imidazole (FcIm) and two related methyl-imidazolium salts (FcMIm+I- and FcMIm+PF6-) were synthesized for their incorporation into plasticized PVC by solvent casting technique. The obtained materials were investigated for their thermal stability and, compared to pure polymer, films containing ionic ferrocene derivatives in 0.5% w/w loading were found slightly more stable. The pure ferrocene compounds showed antibacterial activity against Staphylococcus epidermis, but not against Escherichia coli, with a maximum for FcMIm+PF6- salt. After incorporation into PVC polymer, antibacterial activity against S. epidermis was observed (by disk diffusion test) only for PVC/FcMIm+PF6- (5% w/w) film, from which a release of 14.6% of the ferrocenilimidazolium cation in aqueous medium was measured after 24 hr.


80) Compostable Polylactide and Cellulose Based Packaging for Fresh-Cut Cherry Tomatoes: Performance Evaluation and Influence of Sterilization Treatment

M.Rapisarda, C.Patanè, A.Pellegrino, A.Malvuccio, V.Rizzo, G.Muratore, P.Rizzarelli

Materials  13(15),  3432  - 2020

DOI: https://doi.org/10.3390/ma13153432
For food packaging, plastic materials display large appeal, mostly due to their versatility, mechanical, optical and barrier properties. However, they play an important role in environmental concerns and waste management issue. Compostable bioplastics represent alternative materials designed for a lower environmental impact. In this work, a biobased compostable packaging, constituted by polylactide (PLA) trays and NatureFlexTM film, was evaluated for fresh-cut cherry tomato. A comparative analysis was accomplished using traditional packaging materials, that is, polyethylene terephtalate (PET) trays and polypropylene (PP Coex) film. Structural stability under food contact conditions, mechanical and physical-chemical properties were investigated. Tensile mechanical properties, puncture resistance, contact angle (CA) and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), before and after UV or radiofrequency (RF) sterilization treatment, were evaluated. UV irradiation method resulted the less invasive one. Therefore, oxygen and water vapor transmission rate (OTR and WVTR), overall chemical migration test, biodegradation assessment by biochemical oxygen demand (BOD) according to ISO 14851 and disintegration test by ISO 20200 were carried out to establish the further influence of UV sterilization on the packaging. Overall, data showed that the biobased compostable packaging for a prolonged shelf-life of fresh-cut cherry tomato has better properties that were surprisingly enhanced by the UV treatment.

IPCB graphical abstract



81) Synthesis and Characterization of Copoly(Ether Sulfone)s with Different Percentages of Diphenolic Acid Units

A.Scamporrino, C.Puglisi, A.Spina, M.S.Montaudo, D.Zampino, G.Cicala, G.Ognibene, C.Di Mauro, S.Dattilo, E.F.Mirabella, G.Recca, F.Samperi

Polymers  12(8),  1817  - 2020

DOI: https://doi.org/10.3390/polym12081817
New functionalized Poly(ether sulfone)s having different molar ratio (10, 20, 30, 50, 70, 100 mol%) of 4,4-bis phenoxy pentanoic acid unit (diphenolic acid; DPA) units were synthesized and characterized by (1H and 13C)-NMR, MALDI-TOF MS, FT-IR, DSC and DMA analyses. The microstructural analysis of the copolymers, obtained by 13C-NMR using an appropriate statistical model, shows a random distribution of copolymer sequences, as expected. The presence of different amount of DPA units along the polymer chains affects the chemical and physical properties of the copolymers. The Tg and the contact angle values decrease as the molar fraction of DPA units increases, whereas the hydrophilicity increases. NMR and MALDI-TOF MS analyses show that all polymer chains are almost terminated with hydroxyl and chlorine as end groups. The presence of cyclic oligomers was also observed by MALDI-TOF MS analysis.

IPCB graphical abstract



82) Hydrodistillation of Trachelospermum jasminoides Lindl. flowers. An analysis of essential oil, hydrolate and polyphenols content of the process wastes.

E.Napoli, S.Dattilo, G.Ruberto

Journal of Essential Oil Research   - 2020

DOI: https://doi.org/10.1080/10412905.2020.1808538
Trachelospermum jasminoides
(Lindl.) is a woody evergreen plant of the Apocynaceae family mainly used as ornamental/hedge plant. Its stems and leaves are used in traditional Chinese medicine with the name of 'Luoshiteng' . Although some studies have been devoted to the phytochemistry of luoshiteng, little is known about the chemical composition of its flowers. In this study, the volatile composition of the flowers of T. jasminoides has been studied. The Gas chromatographic - Mass spectrometry analysis (GC/FID-MS) of the essential oil and hydrolate allowed identifying 43 compounds with linalool as the main compound for both of them. Phytochemical investigation was completed by the High Performance Liquid Chromatography - Mass spectrometry (HPLC/DAD-ESI-MS) analysis of hydrodistillation wastes (liquid and solid) which revealed the presence of biologically active compounds such as chlorogenic acids and other polyphenols. This study contributes to the definition of the phytochemistry of T. jasminoides and provides the first data on the composition of the hydrodistillation wastes preparatory to their valorisation in the future.


83) Thermal Degradation Processes of Aromatic Poly(Ether Sulfone) Random Copolymers Bearing Pendant Carboxyl Groups

S.Dattilo, C.Puglisi, E.F.Mirabella, A.Spina, A.Scamporrino, D.Zampino, I.Blanco, G.Cicala, G.Ognibene, C.Di Mauro, F.Samperi

Polymers  12(8),  1810  - 2020

DOI: https://doi.org/10.3390/polym12081810
Thermal degradation processes of poly(ether sulfone) random copolymers having different molar amount of diphenolic acid (DPA) units were studied by direct-pyrolysis/mass spectrometry, stepwise pyrolysis-gas chromatography/mass spectrometry and thermogravimetric techniques. Results highlighted that thermal degradation processes occur in the temperature range from 370 to 650 °C, yielding a char residue of 32-35 wt%, which decreases as the mol% of DPA units rises. The pyrolysis/mass spectra data allowed us to identify the thermal decomposition products and to deduce the possible thermal degradation mechanisms. Thermal degradation data suggest that the decarboxylation process of the pendant acid moiety mainly occurs in the initial step of the pyrolysis of the copolymers studied. Successively, the scission of the generated isobutyl groups occurs in the temperature range between 420 and 480 °C. Known processes involving the main chain random scission of the diphenyl sulfone and diphenyl ether groups were also observed.


84) Triggering the gas transport in PVdF-HFP membranes via imidazolium ionic liquids

P.Bernardo, D.Zampino, G.Clarizia

Separation and Purification Technology  250,  117201  - 2020

DOI: https://doi.org/10.1016/j.seppur.2020.117201
Ionic Liquids (ILs) are attractive additives for developing advanced polymeric membranes owing to their low volatility, high chemical, thermal stability, affinity for specific gases and ability to influence membrane morphology. Self-standing poly(vinylidenefluoride-co-hexafluoropropylene)-based films were prepared by solution casting and solvent evaporation, incorporating selected imidazolium ILs up to 60 wt.%. The films were characterized for morphology, thermal properties and stability, and spectral properties by scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis and Fourier transform infrared spectroscopy. Blend membranes resulted non-porous, with a spherulitic structure. ILs trigger the conversion of the polymer matrix from a predominantly apolar α-phase to polar crystalline phases, as also shown by the FT-IR results. The polymer blends resulted heterogeneous as shown by DSC and TGA analysis. The thermogravimetric analysis showed a reduced onset of degradation for the blends, with no evidence of complexation between polymer and the ILs. The calorimetric analysis suggested a plasticizing action due to the ionic liquids. This behaviour agrees with the experimental and modelling study on gas permeability. Indeed, the blend membranes displayed a significant enhancement of gas permeability (up to three order of magnitude) at the highest ionic liquid content. The ideal CO2/N2 selectivity was simultaneously improved more than 200% upon the addition of the BF4-based IL to the polymer. The observed gas transport properties were correlated to the anion chemistry and to the specific polymer/IL interactions.


85) Heterogenized Imidazolium-Based Ionic Liquids in Pebax®Rnew. Thermal, Gas Transport and Antimicrobial Properties

G.Clarizia, P.Bernardo, S.Carroccio, M.Ussia, C.Restuccia, L.Parafati, A.Calarco, D.Zampino

Polymers  12(6),  1419  - 2020

DOI: https://doi.org/10.3390/polym12061419
Imidazolium-based ionic liquids (ILs) have interesting antimicrobial activity and their inclusion in a flexible film is ideal to take advantage of their properties in practical applications. Poly(ether-block-amide) (Pebax®Rnew) films were prepared by solution casting, loading two synthetized ILs (1-hexadecyl-3-methylimidazolium dimethyl-5-sulfoisophthalate [Hdmim][DMSIP], IL1 and 1-octyloximethyl-3-methylimidazolium hexafluorophosphate [OOMmim][PF6], IL2) up to 5 wt.%. The ILs were characterized by 1H NMR and MALDI-TOF spectroscopy. The films were investigated for miscibility, morphology, wettability, spectral properties and gas transport. The films display a good thermal stability (>200 °C). Differential scanning calorimetry (DSC) proves phase separation in the blends, that is consistent with FTIR analysis and with the island-like surface morphology observed in the micrographs. Gas permeability tests revealed that the IL-loaded films are dense and poreless, keeping the selectivity of the polymer matrix with a somewhat lessened permeability owing to the impermeable ILs crystals. The film antimicrobial activity, evaluated against Gram-negative and Gram-positive bacterial strains, was correlated to the structure of the incorporated ILs. The smaller IL2 salt did not modify the hydrophobic nature of the neat polymer and was readily released from the films. Instead, IL1, having a longer alkyl chain in the cation, provided a promising antimicrobial activity with a good combination of hydrophilicity, permeability and thermal stability.


86) N-methyl-D-glucamine based cryogels as reusable sponges to enhance heavy metals removal from water

T.Mecca, M.Ussia, D.Caretti, F.Cunsolo, S.Dattilo, S.Scurti, V.Privitera, S.Carroccio

Chemical Engineering Journal  399,  125753  - 2020

DOI: https://doi.org/10.1016/j.cej.2020.125753
The design of novel cryogels containing N-methyl-D-glucamine (NMG) group was herein reported. The macroporous materials were prepared via sustainable and feasible cryopolymerization by using as co-monomers (4-vinyl-benzyl)-N-methyl-D-glucamine (VbNMG) and 2-hydroxyethyl methacrylate (HEMA) at different percentages. Particularly, cryogel containing 100% of VbNMG (VbNMG-100) showed excellent ability in fast water uptake, removing arsenic (V) and chromium (VI) metal ions from it. Reusability up to six cycles was also demonstrated. The as-prepared materials were characterized by spectroscopic, thermal, and morphological analyses. The effect of initial oxyanions concentration, kinetic profiles, interfering anions (phosphate and sulphate) were investigated and adsorption/desorption studies were carried out. Equilibrium sorption results well fitted the Langmuir isotherm for both ions tested, showing a startling aptitude in arsenic (76.3 mg/g) as well as chromium (130.9 mg/g) sorption properties if compared with similar polymers as well as other materials. Exploiting its spongy nature, only 5 mins were needed to absorb contaminated medium releasing purified water by a simple squeezing. Most importantly, the sponge can be easily regenerated and reused again up to three times without the depletion of its efficiency.

IPCB graphical abstract



87) Pollen viability and endophytic yeast species of Cistus creticus and C. monspeliensis

D.Zampino, A.Duro, S.Sciandrello, L.Parafati, C.Restuccia

Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology   - 2020

DOI: https://doi.org/10.1080/11263504.2020.1753844
Cistus species are widespread in the Mediterranean basin, especially in places characterized by high temperatures and arid soils. Despite a rich literature concerning the biological and pharmacological properties of Cistus species, to our knowledge, there are only few reports on pollen viability and little is known about microbial endophytes within pollen grains. Pollen viability and germination of Cistus creticus L. and C. monspeliensis L., from two sites of Sicily (Italy) over two years (2016-2017), were determined by 2,3,5 triphenyl-tetrazolium chloride (TTC) staining and an in vitro germination test. Dominant microorganisms, flowing from pollen openings (colpora), were identified by molecular methods. Furthermore, for comparison, in 2017 microbial endophytes of C. eriocephalus Viv. from Serra S. Bruno (Calabria, Italy) were studied. The optimal medium composition for rapid in vitro germination was determined. Pollen viability was in the range of 79.8-90.0% for C. monspeliensis and 86.6-91.6% for C. creticus, while germination was 56.5?62.4% for C. monspeliensis and 50.1?58.8 for C. creticus. Statistical analysis by correlation coefficient showed a significant relationship between viability and germination, whereas significant differences (P<0.05) were observed between TTC staining and the in vitro germination test. Yeasts were the dominant microorganisms in all pollen samples and dominant species were identified.


88) Role of Organo-Modifier and Metal Impurities of Commercial Nanoclays in the Photo- and Thermo-Oxidation of Polyamide 11 Nanocomposites

M.Ussia, G.Curcuruto, D.Zampino, N.T.Dintcheva, G.Filippone, R.Mendichi, S.Carroccio

Polymers  12(5),  1034  - 2020

DOI: https://doi.org/10.3390/polym12051034
The photo-oxidative degradation processes of bio-based PA11 nanocomposites containing montmorillonite (MMT) and the organo-modified Cloisite®30B were investigated to discriminate the influence of organo-modified components on the polymer durability. Indeed, despite the extensive studies reported, there are still ambiguous points to be clarified from the chemical point of view. To this aim, UV-aged materials were analyzed by Size Exclusion Chromatography (SEC), Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). This enabled determining changes in both chemical structure and Molar Masses (MMs) induced by light, heat and oxygen exposure. The addition of organo-modified nanoclays strongly affected the PA11 light durability, triggering the macromolecular chains scission due to the typical αH, Norrish I and II mechanisms. However, the main contribution in boosting the photo-oxidative degradation is induced by iron impurities contained into the clays. Conversely, thermo-oxidation process performed at 215 °C was unambiguously affected by the presence of the organo-modifiers, whose presence determined an enhancement of crosslinking reactions.


89) Comparative Investigation on the Soil Burial Degradation Behaviour of Polymer Films for Agriculture before and after Photo-Oxidation

F.P.La Mantia, L.Ascione, M.C.Mistretta, M.Rapisarda, P.Rizzarelli

Polymers  12(4),  753  - 2020

DOI: https://doi.org/10.3390/polym12040753
Polymer films based on biodegradable polymers, polyethylene (PE) and modified PE with oxo-degradable additive were prepared by film blowing. Carbon black (1%) was added to all the films. Commercial biodegradable Ecovio® and Mater-Bi® samples were used. Mechanical properties, soil burial degradation and surface wettability were investigated, before and after UV irradiation. Chemical modifications induced by UV and soil degradation, or a synergic effect, were highlighted by Attenuated Total Reflection-Fourier Transform Infra-Red (ATR-FTIR). Photo-oxidized film samples with an elongation at break equal to 50% and 0.5 the initial value were selected for the soil burial degradation test at 30 °C. Weight loss measurements were used to follow biodegradation in soil. Predictably, the degradation in soil was higher for biodegradable polymer-based films than for the PE-based ones. UV irradiation increased surface wettability and encouraged the disintegration in soil of all the samples. In fact, photo-oxidation produced a molar mass reduction and hydrophilic end groups, thus increasing surface erosion and weight loss. This paper not only supplies new criteria to evaluate the performance of biodegradable films in agriculture, before and after lifetime, but also provides a comparative analysis on the soil burial degradation behaviour with traditional ones.

IPCB graphical abstract



90) Ionic Liquid as Dispersing Agent of LDH-Carbon Nanotubes into a Biodegradable Vinyl Alcohol Polymer

V.Bugatti, G.Viscusi, A.Di Bartolomeo, L.Iemmo, D.Zampino, V.Vittoria, G.Gorrasi

Polymers   12(2),  495  - 2020

DOI: https://doi.org/10.3390/polym12020495
A Zn/Al layered double hydroxides (LDHs) hosting carbon nanotubes (80% of CNTs) was synthesized and dispersed into a commercial biodegradable highly amorphous vinyl alcohol polymer at different loading (i.e., 1; 3; 5; 10 wt %). In order to improve the degree of dispersion of the filler into the polymer matrix, an ionic liquid (IL) based on 1-hexadecyl-3-methylimidazolium dimethyl-5-sodiosulfoisophthalate was added to the composites’ mixtures. Structural characterization of filler and polymeric composites was carried out. The analysis of thermal, mechanical and electrical properties of the composites, resulted improved compared to the unfilled material, allowed to hypothesize a good dispersion of the LDH-CNTs lamellar filler into the polymer matrix-assisted by the ionic liquid. This was demonstrated comparing electrical conductivity of composite at 5% of LDH-CNTs in the presence and in the absence of IL. The experimental results showed that the electrical conductivity of the sample with IL is four orders of magnitude higher than the one without IL. Furthermore, the percolation threshold of the whole system resulted very low–0.26% of LDH-CNTs loading, which is 0.21% of CNTs.


91) Novel Amino Acid Assembly in the Silk Tubes of Arid-Adapted Segestriid Spiders

E.Conti, S.Dattilo, A.Scamporrino, G.Costa, F.Samperi

Journal of Chemical Ecology Journal of Chemical Ecology Journal of Chemical Ecology  46,  48-62  - 2020

DOI: https://doi.org/10.1007/s10886-019-01127-8
We investigated in different sites inside or outside the Namib Desert the amino acids composition of the protein material forming the tube silk of Ariadna spiders. These spiders belong to the primitive Segestriidae family and spend their life inside vertical silk burrows dug within the sandy and gravelly soil of arid areas. The silks, previously purified by solubilization in hexafluoroisopropanol, were subjected to partial or total acid hydrolysis. Partial hydrolyzed samples, analyzed by mass spectrometry (matrix assisted laser desorption/ionization and electrospray), led to relevant information on the amino acid sequences in the proteins. The free amino acids formed by complete hydrolysis were derivatized with the Marfey’s reagent and characterized by electrospray mass spectrometry. The reconstruction of the amino acids highlights a homogeneous plan in the chemical structure of all the analyzed silks. Eight amino acids constituting the primary structure of the proteins were identified. Alanine and glycine are the most abundant ones, with a prevalence of alanine, constituting together at least 61% of the chemical composition of the protein material, differently from what occurs in known spidroins. High percentages of proline, serine and threonine and low percentages of leucine complete the peculiarity of these proteins. The purified silks were also characterized by Fourier-transform Infrared Spectroscopy and their thermal properties were investigated by differential scanning calorimetry. The comparison of the silk tubes among the various Namibian populations, carried out through a multivariate statistical analysis, shows significant differences in their amino acid assembly possibly due to habitat features.


92) Mass spectrometry in bioresorbable polymer development, degradation and drug release tracking

P.Rizzarelli, M.Rapisarda, G.Valenti

Rapid Communications in Mass Spectrometry   - 2020

DOI: https://doi.org/10.1002/rcm.8697
A detailed characterization of polymeric matrices and appropriate degradation monitoring techniques are required to sustain the development of new materials as well as to enlarge the applications of the old ones. In fact, polymer analysis is essential for the clarification of the intrinsic relationship between structure and properties that ascertains the industrial applications in diverse fields. In bioresorbable and biodegradable polymers, the role of analytical methods is dual since it is pointed both at the polymeric matrices and at degradation tracking. The structural architectures, the mechanical and morphological properties, as well as the degradation rate are of outstanding importance for a specific application. In some cases, the complexity of the polymer structure, the processes of decomposition or the low concentration of the degradation products need the concurrent use of different analytical techniques, which complement each other, to give detailed information of the reactions taking place. Several analytical methods are used in bioresorbable polymer development and degradation tracking. Among them, mass spectrometry (MS) plays an essential role and it is used to refine polymer syntheses, for its high sensitivity, to highlight degradation mechanism by detecting compounds present in trace amount, or tracking the degradation product profile as well as to study drug release. In fact, elucidation of reaction mechanisms and polymer structure, attesting the purity and detecting defects as well as residual catalysts, in biodegradable and bioresorbable polymers requires sensitive analytical characterization methods that are essential in providing an assurance of safety, efficacy and quality. This review aims to provide an overview of the MS strategies used to support research and development of resorbable polymers as well as to investigate the degradation mechanism. It is focused on the most significant studies concerning synthetic bioresorbable matrices (polylactide, polyglycolide and their copolymers, polyhydroxybutyrate, etc.), published in the last ten years.


93) Preferential removal of pesticides from water by molecular imprinting on TiO2 photocatalysts

R.Fiorenza, A.Di Mauro, M.Cantarella, C.Iaria, E.M.Scalisi, M.V.Brundo, A.Gulino, L.Spitaleri, G.Nicotra, S.Dattilo, S.Carroccio, V.Privitera, G.Impellizzeri

Chemical Engineering Journal  379 (2020)  - 2020

DOI: https://doi.org/10.1016/j.cej.2019.122309
In order to achieve a selective removal of specific pesticides from water, we synthesized, through the sol-gel technique, molecularly imprinted TiO2 photocatalysts with the only use of the standard reactants of the TiO2 sol-gel synthesis together with the pesticide molecules, without any addition of further reactants supports or matrices. It is a new, easy, smart and scalable method that avoid the multistep and solvent-consuming procedures, typical of the molecular imprinting. Two widely-used pesticides, i.e. the herbicide 2,4D, and the insecticide imidacloprid, were chosen as template for the molecular imprinting and as contaminants target for the photocatalytic tests. A remarkable enhancement of the photocatalytic activity was verified with the TiO2 imprinted with the corresponding pesticide-target. The selectivity of the photodegradation process was verified thanks to the comparison with the degradation of pesticides not-used as template. Furthermore, the eventual toxic effects of the molecularly imprinted materials were evaluated by biological tests. The combination of molecular imprinting with photocatalysis, here investigated for the first time with pesticides, it is a promising strategy to selectively catch (through the molecular imprinting process) and degrade (through the photocatalysis) specific organic contaminants from water.

IPCB graphical abstract



94) ALG12-CDG: novel glycophenotype insights endorse the molecular defect

L.Sturiale, S.Bianca, D.Garozzo, A.Terracciano, E.Agolini, A.Messina, A.Palmigiano, F.Esposito, Ch.Barone, A.Novelli, A.Fiumara, J.Jaeken, R.Barone

Glycoconjugate journal  36,  461-472  - 2019

DOI: https://doi.org/10.1007/s10719-019-09890-2
Congenital disorders of glycosylation (CDG) are genetic diseases characterized by deficient synthesis (CDG type I) and/or abnormal processing (CDG type II) of glycan moieties linked to protein and lipids. The impact of the molecular defects on protein glycosylation and in turn on the clinical phenotypes of patients with CDG is not yet understood. ALG12-CDG is due to deficiency of ALG12 α1,6-mannosyltransferase that adds the eighth mannose residue on the dolichol-PP-oligosaccharide precursor in the endoplasmic reticulum. ALG12-CDG is a severe multisystem disease associated with low to deficient serum immunoglobulins and recurrent infections. We thoroughly investigated the glycophenotype in a patient with novel ALG12 variants and immunodeficiency. We analyzed serum native transferrin, as first line test for CDG and we profiled serum IgG and total serum N-glycans by a combination of consolidated (N-glycan analysis by MALDI MS) and innovative mass spectrometry-based protocols, such as GlycoWorks RapiFluor N-glycan analysis coupled with LC-ESI MS. Intact serum transferrin showed, as expected for a CDG type I defect, underoccupancy of N-glycosylation sites. Surprisingly, total serum proteins and IgG N-glycans showed some specific changes, consisting in accumulating amounts of definite high-mannose and hybrid structures. As a whole, ALG12-CDG behaves as a dual CDG (CDG-I and II defects) and it is associated with distinct, abnormal glycosylation of total serum and IgG N-glycans. Glycan profiling of target glycoproteins may endorse the molecular defect unraveling the complex clinical phenotype of CDG patients.


95) Characterization and laser-induced degradation of a medical grade polylactide

P.Rizzarelli, G.Piredda, S.La Carta, E.F.Mirabella, G.Valenti, R.Bernet, G.Impallomeni

Polymer Degradation and Stability  169,  108991  - 2019

DOI: https://doi.org/10.1016/j.polymdegradstab.2019.108991
In this study, we carried out the structural and thermal characterization of a medical-grade poly (lactide) (PLA) by SEC, TGA, DSC, NMR, ICP-MS and Py-GC/MS. Moreover, we investigated the laser-induced degradation occurring when ultrashort laser pulses (ULP) were employed to cut extremely thin polymer films prepared by solvent-casting. ULP polymer cutting technology is an interesting manufacturing process for its advantages in potential medical applications. In fact, heat transmission to the region surrounding the cuts is limited, so that the incisions are precise and the effects on the regions around them are small. In this way, the need for post-processing is reduced and ULP cutting becomes interesting for industrial applications. However, degradation induced by ULP may occur and compromise the properties of the polymer samples. To investigate this possibility, portions of PLA films, ultrashort laser cut (ULC) and uncut, were analysed by SEC, DSC, NMR and FTIR. Furthermore, PLA oligomers were studied by ESI-MS. Both SEC and NMR showed a decrease in the molecular weight. FTIR, ESI-MS and NMR spectra revealed the presence of olefin end groups originated from a β-H transfer mechanism, induced by heat and/or light (Norrish II mechanism). Additionally, the inspection of the ESI mass spectra highlighted the cleavage of ester bonds related to the Norrish I type mechanism, undetected by the other techniques.

IPCB graphical abstract



96) Photo-Oxidative and Soil Burial Degradation of Irrigation Tubes Based on Biodegradable Polymer Blends

M.Rapisarda, F.P.La Mantia, M.Ceraulo, M.C.Mistretta, C.Giuffrè, R. Pellegrino, G.Valenti, P.Rizzarelli

Polymers  11(9),  1489  - 2019

DOI: https://doi.org/10.3390/polym11091489
Irrigation tubes based on biodegradable polymers were prepared via an extrusion-drawing process by Irritec and compared to conventional pipes made of high-density polyethylene (HDPE). A commercial polylactide/poly (butyleneadipate-co-butyleneterephthalate) (PLA/PBAT) blend (Bio-Flex®) and Mater-Bi® were used. The polymers were characterized from rheological and mechanical points of view. Irrigation pipes were subjected to photoaging with continued exposure to UV radiation up to 22 days. The degradability in the soil of irrigation tube samples was studied. The influence of temperature and UV irradiation on soil burial degradation was investigated. A soil burial degradation test was carried out at 30 °C and 50 °C for up to 70 days. The degree of degradation was evaluated from the weight loss percentage. The degradation rate of irrigation tube samples based on Mater-Bi® was higher at 30 °C and was stimulated after 14 days of UV irradiation. Higher temperatures or UV aging encouraged the disintegration in soil of Bio-Flex®-based irrigation tubes. Furthermore, tube samples, before and after UV and soil burial degradation, were analyzed by Attenuated Total Reflection-Fourier Transform Infra-Red (ATR-FTIR) spectroscopy.


97) Hybrid nickel-free graphene/porphyrin rings for photodegradation of emerging pollutants in water

M.Ussia, M.Urso, M.Miritello, E.Bruno, G.Curcuruto, D.Vitalini, G.G.Condorelli, M.Cantarella, V.Privitera, S.Carroccio

RSC Advances  2019(52),  30182  - 2019

DOI: https://doi.org/10.1039/C9RA06328E
A novel hybrid photoactive material based on graphene foam (G) coupled with porphyrin-based polymers (Porph rings) was formulated by using a time-saving procedure to remove nickel from the final device. Specifically, Porph rings were spin coated onto the G platform with the double function of a visible-light photocatalyst and protective agent during nickel etching. The characterization of G-Porph rings was assessed by Scanning Electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). The novel material showed photocatalytic ability in degrading different classes of pollutants such as the herbicide 2,4 dichlorophenoxyacetic acid (2,4-D), polyethylene glycol (PEG) as an ingredient of care and health products, and also the methylene blue (MB) dye. UV-Vis spectroscopy, total organic carbon (TOC) and soft mass spectrometry techniques were used to monitor the photocatalytic process. The best performance in terms of photocatalytic efficiency was exhibited versus PEG and MB degradation. Furthermore, to determine the individual contribution of Reactive Oxygen Species (ROS) produced, free radical and hole scavenging tests were also carried out. Finally, a detailed map of the photocatalytic degradation mechanisms was proposed, reporting also the calculation of Porph rings’ Highest Occupied Molecular Orbital (HOMO) and Lowest Occupied Molecular Orbital (LUMO) energy level values.

IPCB graphical abstract



98) A Novel Composite Material for Foldable Building Envelopes

G.Rodonò, V.Sapienza, G.Recca, D.Carbone

Sustainability  11(17),  4684  - 2019

DOI: https://doi.org/10.3390/su11174684
Contemporary research is increasingly focused on studying buildings that either interact with environmental boundaries or adapt themselves to their users’ needs. In the current literature, this kind of ability is given different names: responsivity, adaptability, smartness. These are different ways to refer to a common concept, with subtle nuances. Foldable surfaces are one of the most interesting geometries able to give responsivity to building components, but often their production is complex and expensive. The aim of this research was the creation of a novel material that can provide lightweight solutions for foldable building envelopes. This composite material can be folded and unfolded easily, like a sheet of paper, but with a higher mechanical performance. It is made with the thermoplastic elastomer SEBS (styrene-ethylene-butylene-styrene) as its matrix, as well as a fabric reinforcement. In this paper, following an introduction to this subject, the authors present the composite material’s production methods and its mechanical characterization.


99) Mechanical and thermal properties of fly ash-filled geopolymers

M.Catauro, E.Tranquillo, F.Barrino, G.Dal Poggetto, I.Blanco, G.Cicala, G.Ognibene, G.Recca

Journal of Thermal Analysis and Calorimetry   - 2019

DOI: https://doi.org/10.1007/s10973-019-08612-y
Fly ash recycling reduces the amount of waste to be treated or disposed in landfills, allowing both to decrease the environmental damage and to save the costs of transport and disposal of waste. Systems with different percentages in mass of fly ash (20, 50 and 70 mass%) and the remaining part of pure metakaolin were synthesized. The effect of fly ash on the mechanical and thermal properties of a new geopolymer has been investigated in this paper. Fourier transform infrared spectroscopy has allowed us to verify the bonds formation between the geopolymeric matrix and the fly ash. The consolidation of the materials has been confirmed by pH and conductivity at up to 28 days of hardening. Dynamic mechanical analysis, differential scanning calorimetry and thermogravimetric analysis were performed in order to evaluate the thermo-mechanical performance of this new geopolymer in comparison with its counterpart pure geopolymer.


100) Interlaminar Toughening of Epoxy Carbon Fiber Reinforced Laminates: Soluble Versus Non-Soluble Veils

G.Ognibene, A.Latteri, S.Mannino, L.Saitta, G.Recca, F.Scarpa, G.Cicala

Polymers  11(6),  1029  - 2019

DOI: https://doi.org/10.3390/polym11061029
This work describes the evaluation of different interlaminar veils to improve the toughening of epoxy/carbon fiber composites manufactured by resin infusion. Three commercial veils have been used in the study: two electro spun thermoplastic nanofiber (Xantulayr® from Revolution Fibres) with different areal weight, and one micro carbon fibers veil (Optiveil® from TFP). Two laboratory made veils were also manufactured by electrospinning commercial polyethersulfone (PES) tougheners (Virantage by Solvay). The veils were selected to be either soluble or non-soluble in the epoxy resin matrix during curing. The solubility was analyzed by scanning electron microscopy and dynamic mechanical analysis testing on the cured laminates. The fracture energy was evaluated by double cantilever bending (DCB) testing under Mode I loading. The insoluble thermoplastic nanofibers showed the highest toughening efficiency, followed by the soluble nanofiber veils. The carbon fiber based veil showed no toughness improvement.

IPCB graphical abstract



101) Physicochemical Properties of A New PEGylated Polybenzofulvene Brush for Drug Encapsulation

M.Paolino, A.Reale, V.Razzano, G.Giuliani, A.Donati, G.Giorgi, A.C.Boccia, R.Mendichi, D.Piovani, C.Botta, L.Salvini, F.Samperi, C.Savoca, M.Licciardi, E.Paccagnini, M.Gentile, A.Cappelli

Pharmaceutics   11(9)  - 2019

DOI: https://doi.org/10.3390/pharmaceutics11090444
A new polymer brush was synthesized by spontaneous polymerization of benzofulvene macromonomer 6-MOEG-9-T-BF3k bearing a nona(ethylene glycol) side chain linked to the 3-phenylindene scaffold by means of a triazole heterocycle. The polymer structure was studied by SEC-MALS, NMR spectroscopy, and MALDI-TOF MS techniques, and the results supported the role of oligomeric initiatory species in the spontaneous polymerization of polybenzofulvene derivatives. The aggregation features of high molecular weight poly-6-MOEG-9-T-BF3k-FE were investigated by pyrene fluorescence analysis, dynamic light scattering studies, and transmission electron microscopy, which suggested a tendency towards the formation of spherical objects showing dimensions in the range of 20-200 nm. Moreover, poly-6-MOEG-9-T-BF3k-FE showed an interesting cytocompatibility in the whole concentration range tested that, besides its aggregation features, makes this polybenzofulvene brush a good polymer candidate for nanoencapsulation and delivery of drug molecules. Finally, the photo-physical features of poly-6-MOEG-9-T-BF3k-FE could allow the biodistribution of the resulting drug delivery systems to be monitored by fluorescence microscopy techniques.


102) Unsaturated Poly(Hydroxyalkanoates) for the Production of Nanoparticles and the Effect of Cross-Linking on Nanoparticle Features

R.Pignatello, G.Impallomeni, S.Cupri, G.Puzzo, C.Curcio, M.G.Rizzo, S.Guglielmino, A.Ballistreri

Materials (Basel)  12(6),  868  - 2019

DOI: https://doi.org/10.3390/ma12060868
A biodegradable poly(3-R-hydroxyalkanoate) synthesized by Pseudomonas mediterranea was investigated as a biomaterial to obtain colloidal drug delivery systems. Using a nanoprecipitation method, nanoparticles with a mean size of 155 nm and a negative surface charge were formed. They can be freeze-dried by adding hydroxypropyl-β-cyclodextrin as a cryoprotectant, and they have been shown to efficiently load both a hydrophilic (calcein) and a lipophilic (Nile red) model probe. Since this polymer contains terminal double bonds in the side chains, cross-linking conditions were tested. In particular, under the action of UV rays or irradiation with an incandescent yellow lamp, this polymer tended to cross-link.


103) The role of solvent on the formulation of graphene/polyporphyrin hybrid material versus photocatalytic activity

M.Ussia, F.Ruffino, E.Bruno, E.Spina, I.Conticello, V.Privitera, S.Carroccio

Polymer Bulletin   - 2019

DOI: https://doi.org/10.1007/s00289-019-02849-1
The influence of solvent used to prepare hybrid materials for photocatalytic applications formulated by cyclic bisphenol A/porphyrin copolyformal and graphene is here reported. To this purpose, the polymer is dissolved in different solvents [chloroform, tetrahydrofuran and dimethylformamide (DMF)] and used to impregnate via bath deposition 2D graphene. Depending on the nature of the solvent, polymer coats differently the graphene substrates producing peculiar SEM and AFM data. Microscopic and nanoscopic features of formulated materials were correlated with their photocatalytic activities by using methylene blue degradation test. Data collected under visible-light irradiation reveal as the best photodegradation performance was displayed by graphene coated with DMF copolyporphyrin solution.

IPCB graphical abstract



104) Hyperkinetic movement disorders in congenital disorders of glycosylation

G.Mostile, R.Barone, A.Nicoletti, R.Rizzo, D.Martinelli, L.Sturiale, A.Fiumara, J.Jankovic, M.Zappia

European Journal of Neurology  26(9),  1226-1234  - 2019

DOI: https://doi.org/10.1111/ene.14007
Background and purpose
Congenital disorders of glycosylation (CDG) represent an increasing number of rare inherited metabolic diseases associated with abnormal glycan metabolism and disease onset in infancy or early childhood. Most CDG are multisystemic diseases mainly affecting the central nervous system. The aim of the current study was to investigate hyperkinetic movement disorders in patients affected by CDG and to characterize phenomenology based on CDG subtypes.
Methods
Subjects were identified from a cohort of patients with CDG who were referred to the University Hospital of Catania, Italy. Patients were evaluated by neurologists with expertise in movement disorders and videotaped using a standardized protocol.
Results
A variety of hyperkinetic movement disorders was detected in eight unrelated CDG patients. Involuntary movements were generally observed early in childhood, maintaining a clinical stability over time. Distribution ranged from a generalized, especially in younger subjects, to a segmental/multifocal involvement. In patients with phosphomannomutase 2 CDG, the principal movement disorders included dystonia and choreo-athetosis. In patients affected by other CDG types, the movement disorders ranged from pure generalized chorea to mixed movement disorders including dystonia and complex stereotypies.
Conclusions
Hyperkinetic movement disorder is a key clinical feature in patients with CDG. CDG should be considered in the differential diagnosis of childhood-onset dyskinesia, especially when associated with ataxia, developmental delay, intellectual disability, autism or seizure disorder.


105) SLC35A2-CDG: Functional characterization, expanded molecular, clinical, and biochemical phenotypes of 30 unreported Individuals

B.G.Ng, P.Sosicka, S.Agadi, M.Almannai, C.A.Bacino, R.Barone, L.D.Botto, J.E.Burton, C.Carlston, B.Hon-Yin Chung, J.S.Cohen, D.Coman, K.M.Dipple, N.Dorrani, W.B.Dobyns, A.F.Elias, L.Epstein, W.A.Gahl, D.Garozzo, T.B.Hammer, J.Haven, D.Héron, M.Herzog, G.E.Hoganson, J.M.Hunter, M.Jain, J.Juusola, S.Lakhani, H.Lee, J.Lee, K.Lewis, N.Longo, C.Marques Lourenço, C.C.Y.Mak, D.McKnight, B.A.Mendelsohn, C.Mignot, G.Mirzaa, W.Mitchell, H.Muhle, S.F.Nelson, M.Olczak, C.G.S.Palmer, A.Partikian, M.C.Patterson, T.M.Pierson, S.C.Quinonez, B.M.Regan, M.E.Ross, M.J.Guillen Sacoto, F.Scaglia, I.E.Scheffer, D.Segal, N.Shah Singhal, P.Striano, L.Sturiale, J.D.Symonds, S.Tang, E.Vilain, M.Willis, L.A.Wolfe, H.Yang, S.Yano, Z.Powis, S.F.Suchy, J.A.Rosenfeld, A.C.Edmondson, S.Grunewald, H.H.Freeze

Human Mutation  40(7),  908-925  - 2019

DOI: https://doi.org/10.1002/humu.23731
Pathogenic de novo variants in the X-linked gene SLC35A2 encoding the major Golgi-localized UDP-galactose transporter required for proper protein and lipid glycosylation cause a rare type of congenital disorder of glycosylation known as SLC35A2-congenital disorders of glycosylation (CDG; formerly CDG-IIm). To date, 29 unique de novo variants from 32 unrelated individuals have been described in the literature. The majority of affected individuals are primarily characterized by varying degrees of neurological impairments with or without skeletal abnormalities. Surprisingly, most affected individuals do not show abnormalities in serum transferrin N-glycosylation, a common biomarker for most types of CDG. Here we present data characterizing 30 individuals and add 26 new variants, the single largest study involving SLC35A2-CDG. The great majority of these individuals had normal transferrin glycosylation. In addition, expanding the molecular and clinical spectrum of this rare disorder, we developed a robust and reliable biochemical assay to assess SLC35A2-dependent UDP-galactose transport activity in primary fibroblasts. Finally, we show that transport activity is directly correlated to the ratio of wild-type to mutant alleles in fibroblasts from affected individuals.


106) Trade-off between harvest date and lignocellulosic crop choice for advanced biofuel production in the Mediterranean area

F.Zanetti, D.Scordia, S.Calcagno, M.Acciai, A.Grasso, S.L.Cosentino, A.Monti

Industrial Crops and Products  138(5),  111439  - 2019

DOI: https://doi.org/10.1016/j.indcrop.2019.06.002
Advanced biofuel production requires feedstock with specific composition in terms of quantity and quality. Decisions about the harvest time of perennial energy grasses have important implications for bioconversion process as well as for the life-span of the plant stand. Four-year data from long term-field trials were used to identify the optimal crop-specific harvest date (autumn vs. winter), in relation to advanced biofuel production. Three different perennial energy grasses (i.e., switchgrass, giant reed and miscanthus) were grown at Bologna and Catania (Italy), under northern and southern Mediterranean climate, respectively, adopting a low input management. In addition to the biomass yield and composition, the net energy value (NEV) from agricultural activities, and the energy return on investment (EROI) at the biorefinery gate was also evaluated.
At Bologna, switchgrass biomass yield and quality (hemicellulose, cellulose and acid detergent lignin - ADL) were significantly enhanced when harvested in winter. At Catania, giant reed productivity, cellulose and ADL content were unaffected by harvest date, while hemicellulose and ash content decreased in winter. Biomass composition of miscanthus was more stable in Catania than Bologna, however, yield and components resulted significantly higher in Bologna than Catania, due mainly to the more even precipitation distribution throughout the vegetative crop development. The NEV was positive for all energy crops, treatments and locations, with the highest value for miscanthus grown at Bologna. The EROI of lignocellulosic bioethanol ranged from 4.16 for switchgrass in the autumn harvest at Bologna to 4.37 for miscanthus grown at Catania, which showed also the highest theoretical bioethanol production (169.2 kg h-1) at a feeding rate of 300 kg h-1 of raw material. Nonetheless, miscanthus grown at Bologna attained the highest bioethanol yield (12,254 L ha-1).
This study proved that investigated perennial grasses are worth to be grown as lignocellulosic feedstock under low input for at least one decade, upon which Mediterranean region biorefineries may gain fourfold the energy invested.


107) Characterization of the Salmonella Typhimurium core oligosaccharide and its reducing end 3-deoxy-D-manno-oct-2-ulosonic acid used for conjugate vaccine production

G.De Benedetto, F.Micoli, S.Londero, L.Salvini, L.Sturiale, D.Garozzo, N.Ravenscroft, C.Giannelli, P.Cescutti

Carbohydrate Research  481,  43-51  - 2019

DOI: https://doi.org/10.1016/j.carres.2019.05.014
One of the strategies adopted for the development of a bivalent conjugate vaccine against invasive nontyphoidal Salmonella consists of linking the O-antigen component of S.Typhimurium and S.Entertidis lipopolysaccharides to the carrier protein CRM197, a non-toxic variant of diphtheria toxin. The conjugation reaction uses the reducing end residue 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) of the core to which the O-antigen chain is bound (OAg-core). OAg-core chains are cleaved from the lipid A directly in the fermentation broth by mild acid treatment. Kdo has been reported to undergo structural changes under these conditions and therefore the Kdo at the reducing end was thoroughly analysed to verify its structural integrity. For this purpose, low molecular mass OAg-core chains extracted from S.Typhimurium wild type bacteria and core oligosaccharides extracted from S.Typhimurium bacteria mutated not to produce O-antigen repeats were characterized by GLC-MS, MALDI-TOF-MS and NMR spectroscopy. Moreover, a combination of 1H-1H and 1H-13C experiments confirmed the linkage positions, sequence and structure of the octasaccharide core with 5-linked Kdo present at the reducing end in its native structure: α-GlcpNAc-(1→2)-α-Glcp-(1→2)-α-Galp-(1→3)-[α-Galp-(1→6)]-α-Glcp-(1→3)-[α-Hepp-(1→7)]-α-Hepp-(1→3)-α-Hepp-(1→5)-Kdo.

IPCB graphical abstract



108) The N-glycan structures of the antigenic variants of chlorovirus PBCV-1 major capsid protein help to identify the virus-encoded glycosyltransferases

I.Speciale, G.A.Duncan, L.Unione, I.V.Agarkova, D.Garozzo, J.Jiménez-Barbero, S.Lin, T.L.Lowary, A.Molinaro, E.Noel, M.E.Laugieri, M.G.Tonetti, J.L.Van Etten, C.De Castro

The Journal of Biological Chemistry  294(14),  5688-5699  - 2019

DOI: https://doi.org/10.1074/jbc.RA118.007182
The chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) is a large dsDNA virus that infects the microalga Chlorella variabilis NC64A. Unlike most other viruses, PBCV-1 encodes most, if not all, of the machinery required to glycosylate its major capsid protein (MCP). The structures of the four N-linked glycans from the PBCV-1 MCP consist of nonasaccharides, and similar glycans are not found elsewhere in the three domains of life. Here, we identified the roles of three virus-encoded glycosyltransferases (GTs) that have four distinct GT activities in glycan synthesis. Two of the three GTs were previously annotated as GTs but the third GT was identified in this study. We determined the GT functions by comparing the wild-type glycan structures from PBCV-1 with those from a set of PBCV-1 spontaneous GT genes mutants resulting in antigenic variants having truncated glycan structures. According to our working model, the virus gene a064r encodes a GT with three domains: domain 1 has a β-L-rhamnosyltransferase activity, domain 2 has an α-L-rhamnosyltransferase activity and domain 3 is a methyltransferase that decorates two positions in the terminal α-L-rhamnose (Rha) unit. The a075l gene encodes a β-xylosyltransferase that attaches the distal D-xylose (Xyl) unit to the L-fucose (Fuc) that is part of the conserved N-glycan core region. Lastly, gene a071r encodes a GT that is involved in the attachment of a semiconserved element, α-D-Rha, to the same L-Fuc in the core region. Our results uncover GT activities that assemble four of the nine residues of the PBCV-1 MCP N-glycans.


109) Molecularly imprinted polymer for selective adsorption of diclofenac from contaminated water

M.Cantarella, S.Carroccio, S.Dattilo, R.Avolio, R.Castaldo, C.Puglisi, V.Privitera

Chemical Engineering Journal  367,  180-188  - 2019

DOI: https://doi.org/10.1016/j.cej.2019.02.146
The presence of pharmaceuticals, such as non-steroidal anti-inflammatory drugs (NSAIDs) in the aquatic environment represents a worldwide threat. NSAIDs are considered "emerging contaminants" of water since the traditional methods are not designed to efficiently remove them. Aiming to overcome the limits of the conventional wastewater treatment plants, we propose molecularly imprinted polymers (MIPs) as valid tools for selective adsorption and removal of these drugs from water. In particular, in this work, we have prepared diclofenac-selective MIP by a simple bulk polymerization process. After the characterization of the synthetized polymers, the binding abilities were evaluated in detail through the adsorption of diclofenac in aqueous solution and compared with the abilities of a corresponding non-imprinted polymer used as a reference. Thanks to the imprinting effect, the prepared MIP adsorbs with extreme selectivity its template molecule, i.e. the diclofenac. This effect was evaluated by testing the adsorption abilities towards different drugs, such as acetylsalicylic acid and trimethoprim. In addition, MIP reusability was demonstrated after a simple regeneration step. The strength of this work is due to the low cost synthesis of MIP and to its optimal performance of molecular recognition in water, differentially from many of the traditional MIPs, usually used with organic solvent. Such peculiarities make the material potentially applicable for water treatment on a large scale.

IPCB graphical abstract



110) Screening of antimicrobial activity of citrus essential oils against pathogenic bacteria and Candida strains

M.Mancuso, M.Catalfamo, P.Laganà, A.C.Rappazzo, V.Raymo, D.Zampino, R.Zaccone

Flavour and Fragrance Journal   - 2019

DOI: https://doi.org/10.1002/ffj.3491
Several studies have indicated that plants are good sources of antimicrobial agents and pharmaceuticals. The present study is focused to evaluate the antimicrobial potential of 11 citrus essential oils (EOs) and terpenes (T), against 18 bacterial pathogenic strains and 4 Candida sp. strains. Volatile compounds present in the citrus EOs were determined by a gas chromatography analysis, allowing the identification of 79 components. Results highlights that lemon, bergamot oil and terpene were effective against more than 54.5% of tested bacteria. Candida spp. strains resulted very sensitive to all terpenes and EOs. Gram negative bacteria showed lower sensitivity than Gram positive ones. Among Gram negative, fish pathogens were sensitive to oils, so we suggested their use as possible alternatives in aquaculture farms to prevent bacterial fish diseases. Moreover, results suggested that citrus oils could be a useful tool in the food industry to prolong the shelf-life.

IPCB graphical abstract



111) Technology assessment of new biodegradable poly(R-3-hydroxybutyrate-co-1,4-butylene adipate) copolymers for drug delivery

T.Musumeci, S.Cupri, A.Bonaccorso, G.Impallomeni, A.Ballistreri, G.Puglisi, R.Pignatello

Journal of Applied Polymer Science  136(12),  47233  - 2019

DOI: https://doi.org/10.1002/app.47233
New biodegradable biomaterials are attracting a huge interest as alternative to conventional polymers used in the field of drug delivery. In this work, we evaluated the ability of new biocompatible and biodegradable polyesters to form nanoparticles (NPs), and tested their potential carrier properties for controlled release of hydrophilic or lipophilic compounds. Multiblock copolymers derived from poly(R-3-hydroxybutyrate) and poly(1,4-butylene adipate) by microwave-assisted transesterification, having different chemical and physicochemical properties were tested. Nanoprecipitation was applied to obtain NPs with a homogenous size distribution. Oil Red O and calcein were encapsulated as lipophilic and hydrophilic probes, evaluating NP mean size and size polydispersity, surface charge, encapsulation efficiency, and release profile. The release curves were fitted into mathematical models to investigate the release mechanism. NPs stability appeared to be strictly related to storage conditions. The NPs were also successfully autoclaved and their mucoadhesive behavior was assessed by a "mucin-particle method."

IPCB graphical abstract



112) Nutritional changes during storage in fresh-cut long storage tomato as affected by biocompostable polylactide and cellulose based packaging

C.Patanè, A.Malvuccio, A.Saita, P.Rizzarelli, L.Siracusa, V.Rizzo, G.Muratore

LWT - Food Science and Technology  101,  618-624  - 2019

DOI: https://doi.org/10.1016/j.lwt.2018.11.069
The effects of storage at 4 °C on some quality and nutritional traits were assessed in fresh-cut fruits of a long storage tomato landrace packaged in biocompostable materials (BIO) or in conventional plastics (CP). Fruits were produced both in greenhouse and open field. Total solids-TS, total soluble solids-TSS, sugar content, titratable acidity, phenols, lycopene, vitamin C, antioxidant activity (DPPH and FRAP) were measured at 0, 4, 7 and 12 days of storage. TS, TSS and sugars overall increased during storage. Phenols did not change (fruits from greenhouse) or declined over time (fruits from open field). Lycopene content dropped after 4 d, keeping unaltered afterwards. Vitamin C decreased during storage. DPPH was reduced whilst FRAP kept constant over time, matching the pattern of phenols. Fresh-cut fruits in BIO retained greater TS (+10-11%), TSS (+4-10%) and sugars (+5-12%) than those in CP. Packaging had minor (on vitamin C) or no effects (on phenols and lycopene). Antioxidant activity was higher in BIO. Fresh-cut tomatoes from open field fruits exhibited better quality than those from greenhouse fruits. Nonetheless, these last attained high quality levels that may encourage long-storage tomato producers, taking into account the commercial benefits deriving from an extended production season.


113) ZnO-pHEMA Nanocomposites: An Ecofriendly and Reusable Material for Water Remediation

M.Ussia, A.Di Mauro, T.Mecca, F.Cunsolo, G.Nicotra, C.Spinella, P.Cerruti, G.Impellizzeri, V.Privitera, S.Carroccio

ACS applied materials and interfaces  10(46),  40100-40110  - 2018

The design of new hybrid nanocomposites based on poly(2-hydroxyethylmethacrylate) (pHEMA) graphene oxide (GO) cryosponges, wherein ZnO nanolayers have been deposited to induce photocatalytic properties, is reported here. Atomic layer deposition at low temperature is specifically selected as the deposition technique to stably anchor ZnO molecules to the pendant polymer OH groups. Furthermore, to boost the pHEMA cryogel adsorption capability versus organic dyes, GO is added during the synthetic procedure. The morphology, the crystallinity, and the chemical composition of the samples are deeply investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction analyses, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Swelling properties, mechanical performance, and adsorption kinetics models of the hybrid materials are also evaluated. Finally, the adsorption and photocatalytic performance are tested and compared for all of the samples using methylene blue as a dye. Particularly, the adsorption efficiency of ZnO/pHEMA and ZnO/pHEMA-GO nanocomposites, as well as their in situ regeneration via photocatalysis, renders such devices very appealing for advanced wastewater treatment technology.

IPCB graphical abstract



114) Densely PEGylated Polybenzofulvene Brushes for Potential Applications in Drug Encapsulation

M.Paolino, G.Grisci, F.Castriconi, A.Reale, G.Giuliani, A.Donati, C.Bonechi, G.Giorgi, R.Mendichi, D.Piovani, A.C.Boccia, M.Canetti, F.Samperi, S.Dattilo, C.Scialabba, M.Licciardi, E.Paccagnini, M.Gentile, Andrea Cappelli

Pharmaceutics   10(4),  234  - 2018

The technique of grafting side chains onto a linear polymeric backbone is commonly used to confer to the new polymeric material with desired properties, such as tunable solubility, ionic charge, biocompatibility, or specific interactions with biological systems. In this paper, two new polybenzofulvene backbones were assembled by spontaneous polymerization of the appropriate benzofulvene monomers (4,6-PO-BF3k and 4',6-PO-BF3k) bearing two clickable propargyloxy groups in different positions of the 3-phenylindene scaffold. Poly-4,6-PO-BF3k and poly-4',6-PO-BF3k were grafted with monomethyl oligo(ethylene glycol) (MOEG) to prepare two new polybenzofulvene brushes (i.e., poly-4,6-MOEG-9-TM-BF3k and poly-4',6-MOEG-9-TM-BF3k) by means of a "grafting onto" approach, that were characterized from the point of view of their macromolecular features, aggregation liability, and in a preliminary evaluation of biocompatibility. The obtained results make these PEGylated polybenzofulvene brushes (PPBFB) derivatives potentially useful as nanocarriers for nanoencapsulation and delivery of drug molecules.


115) Polymeric platform for the growth of chemically anchored ZnO nanostructures by ALD

G.Pellegrino, S.Carroccio, F.Ruffino, G.G.Condorelli, G.Nicotra, V.Privitera, G.Impellizzeri

RSC Advances   8,  521-530  - 2018

The synthesis of hybrid nano-composites in which an inorganic layer is grown on a polymeric surface via chemical bonds, is a challenging goal for many applications from photocatalysis, to sensing and optoelectronics. Herein, we describe on the growth of ZnO nanostructures by an Atomic Layer Deposition (ALD) technique on polyetherimide (poly(2,2’-bis(3,4-dicarboxyphenoxy)phenylpropane)-2-phenylendiimide ULTEM® 1000) substrates. A surface modification consisting of a thermal photo-oxidization process, applied for different exposure times, has been properly performed on the polymer to promote the production of ALD suitable functionalities as reactive surface-sites. The chemical anchoring of the inorganic species from the gas-phase is demonstrated by spectroscopy and mass analyses to exclusively occur on the pre-oxidized films, whilst the ZnO growth does not occur in the untreated ULTEM® films in the operative ALD conditions. Notably, we demonstrate that two different regimes of growth take place in the oxidized polymer as a function of the photo-exposure time. In particular, the formation of a nanostructured coating of ZnO on the polyetherimide surface is found in the case of short-time photo-exposed polyetherimide (ALD-like regime), whilst an intermixed organic/polymer layer is found on the long-time oxidized films (Vapor Phase Infiltration, VPI-like regime). The photocatalytic activity of the synthesized materials has been tested through the degradation of methylene blue dye in aqueous solution under UV light irradiation, to give a proof of concept of a possible application of the nano-composites.

IPCB graphical abstract



116) Influence of the Preparation Method and Photo-Oxidation Treatment on the Thermal and Gas Transport Properties of Dense Films Based on a Poly(ether-block-amide) Copolymer

G.Clarizia, P.Bernardo, G.Gorrasi, D.Zampino, S.Carroccio

Materials   11(8),  1326  - 2018

Dense films based on the hydrophobic Pebax®2533 were prepared by using solution casting in different solvents as well as compression molding and subjected to photo-aging under ultraviolet (UV) irradiation. The influence of the preparation method, including the casting solvents, as well as the UV irradiation time selected to treat the samples, were evaluated in terms of permeation rates of pure gases (CO2, N2, O2, CH4, He, and H2). The transport data were correlated with the microstructure and surface properties by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), as well as water contact angle measurements. The obtained results showed that a controlled photo-oxidation process reduces the hydrophobicity of the Pebax®2533 films, increasing their permeability without compromising their integrity.


117) Comparison of Ultem 9085 Used in Fused Deposition Modelling (FDM) with Polytherimide Blends

G.Cicala, G.Ognibene, S.Portuesi, I.Blanco, M.Rapisarda, E.Pergolizzi, G.Recca

Materials  11(2),  285  - 2018

Polyetherimide (PEI) blends modified by either polycarbonate (PC) or polyethylene terephthalate glycol-modified (PETG) were prepared. The latter modifier (PETG) was an industrial grade widely used for fused deposition modelling (FDM) printing. PEI blends were compared to Ultem 9085, which is the standard PEI grade for FDM printing in advanced applications. All the blends were thoroughly characterized in terms of their rheological, morphological, thermomechanical and tensile properties. Ultem 9085 showed improved rheology for processing over standard PEI. PEI/PC blends with 10 wt % of modifier developed here closely matched the viscosity behavior of Ultem 9085. On the other hand, the blends with low PC content (i.e., less than 20 wt %) outperformed Ultem 9085 in terms of thermal and tensile properties. When PETG was added, similar tensile properties to Ultem 9085 were found. The immiscibility for PC contents higher than 20 wt % deteriorated the tensile properties, making it less attractive for applications, although melt viscosity decreased further for increasing PC contents.


118) Biosynthesis and structural characterization of polyhydroxyalkanoates produced by Pseudomonas aeruginosa ATCC 27853 from long odd-chain fatty acids

G.Impallomeni, A.Ballistreri, G.M.Carnemolla, M.G.Rizzo, M.S.Nicolò, S.P.P.Guglielmino

International Journal of Biological Macromolecules  108,  608-614  - 2018

Pseudomonas aeruginosa ATCC 27853 was cultured on media containing long odd-chain fatty acids. Heptadecanoic, nonadecanoic, and heneicosanoic acids sustained cell growth and resulted in polyhydroxyalkanoate (PHA) accumulation when culturing was conducted under nitrogen starvation conditions. No PHA was produced using a complete or magnesium-deprived medium. The isolated polyesters were characterized by gas chromatography and liquid chromatography-electrospray ionization mass spectrometry (ESI-MS) of methanolyzed samples, 1H and 13C NMR spectroscopy, gel permeation chromatography, ESI MS of partially pyrolyzed samples, and differential scanning calorimetry. These PHAs are composed of seven different odd-chain repeating units starting from 3-hydroxyvalerate, with the highest species being the, to date, unreported constituent 3-hydroxyheptadecanoate, and minor amounts of 2 or 3 even-chain comonomers. The PHAs are soft, sticky, rubber-like materials having glass transition temperatures between -45 and -39 °C, melting temperatures between 48 and 52 °C, enthalpies of melting around 11 J/g, and molar masses ranging from 77 to 188 kg/mol. Statistical analysis of the ESI mass spectra of the products of their partial pyrolysis showed that they are pure copolymers and not a blend of copolymers or homopolymers.


119) Hybrid composites manufactured by resin infusion with a fully recyclable bioepoxy resin

G.Cicala, E.Pergolizzi, F.Piscopo, D.Carbone, G.Recca

Composites Part B: Engineering   132,  69-76  - 2018

Bioepoxy based monomers were formulated with a cure inhibitor and a cleavable amine to obtain a recyclable epoxy system suitable for resin infusion at room temperature. Hybrid flax/ carbon fiber layup were used. Tensile, flexural and dynamo-mechanical properties for the composites were studied. The cured laminates were chemically recycled obtaining from the epoxy matrix a thermoplastic. The recycled was processed by fused deposition modelling (FDM) and injection molding after mixing with short kenaf fibers.


120) Poly-histidine grafting leading to fishbone-like architectures

V.Razzano, M.Paolino, A.Reale, G.Giuliani, A.Donati, G.Giorgi, R.Artusi, G.Caselli, M.Visintin, F.Makovec, S.Battiato, F.Samperi, F.Villafiorita-Monteleone, C.Botta, A.Cappelli

RSC Advances  16,  8638-8656  - 2018

A small series of Morita-Baylis-Hillman adduct (MBHA) derivatives was synthesized and made to react with imidazole, N-acetylhistidine, and N-acetylhexahistidine as models of poly-histidine derivatives. Intriguingly, the reaction of MBHA derivatives 1a and b with imidazole in acetonitrile-phosphate buffered saline (PBS) gave the imidazolium salt biadducts 3a and b as the main reaction products. These results were confirmed by experiments performed with Nacetylhistidine and 1b and suggested the possible occurrence of these structures in the products of poly-histidine labeling with MBHA derivatives 1a and b. These compounds were then transformed into the corresponding water-soluble derivatives 1c-e by introducing oligo(ethylene glycol) chains and their reactivity was evaluated in preliminary experiments with imidazole and then with Nacetylhexahistidine in PBS. The structure of polymeric materials Ac-His-6-MBHA-1d and Ac-His-6-MBHA-1e obtained using ten-fold excesses of compounds 1d and e was investigated using mass spectrometry, NMR spectroscopy, and photophysical studies, which suggested the presence of biadduct residues in both polymeric materials. These results provide the basis for the preparation of fishbone-like polymer brushes, the characterization of their properties, and the exploration of their potential applications in different fields of science such as in vivo fluorogenic labeling, fluorescence microscopy, protein PEGylation, up to the production of smart materials and biosensors.

IPCB graphical abstract



121) An innovative approach for the chemical structural characterization of poly(styrene 4-vinylpyridine) copolymers by matrix-assisted laser desorption/ionization time of flight mass spectrometry

M.S.Montaudo, C.Puglisi, S.Battiato, S.Zappia, S.Destri, F.Samperi

Journal of Applied Polymer Science  135,  46976  - 2018

Poly(styrene-co-4-vinylpyridine) random copolymers with different molar composition were synthesized by nitroxide-mediated controlled-radical polymerization using 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) as a mediator. We record the matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) spectra under various conditions, and we find (at last) that they show mostly intact ions [using 2(-4-hydroxyphenylazo-)benzoic acid as MALDI matrix]. Spectra are highly resolved, and thus they allow for the determination of all end-groups, even some less-abundant ones. Spectra are dominated by intact "dormant" copolymer chains terminated with TIPNO at one end and with (4-Bromo-phenyl)ethyl group (starting fragment) at the other one. Applying the mass analysis of copolymers (MACO) statistical model to the spectra, we show that the MACO/MALDI-TOF mass spectrometry (MS) analysis can be successfully applied to copolymers having a difference between the mass of the comonomers as small as 1 g mol-1 (the styrene and 4-vinylpyridine units are 104.15 and 105.15 g/mol, respectively), which results in overlapping isotopic patterns. The results are accurate: chemical composition evaluated by means of MS agrees with that calculated by 1H-nuclear magnetic resonance, for all copolymers investigated. This analytical method allows to extract detailed information on the composition of the copolymer samples and their structure. Glass transition temperatures of copolymers were also determined by differential scanning calorimetry.

graphical abstract



122) Lipid A Structure and Immunoinhibitory Effect of the Marine Bacterium Cobetia pacifica KMM 3879T

F.Di Lorenzo, A.Palmigiano, S.Albitar-Nehme, M.Pallach, M.Kokoulin, N.Komandrova, L.Romanenko, M.L.Bernardini, D.Garozzo, A.Molinaro, A.Silipo

European Journal of Organic Chemistry   2018 (20-21),  2707-2716  - 2018

The structural elucidation of lipopolysaccharides (LPSs) from Gram-negative marine bacteria, along with the assessment of their immunological properties, is a fascinating and active research field. Such studies can aid understanding of adaptation phenomena that occur in the marine environment, but they can also open up new perspectives on the design and development of new immunoregulatory drugs. In this paper, we report the structural characterization of the lipid A component of the LPS isolated from the marine bacterium Cobetia pacifica KMM 3879T, which is characterized by a family of structures differing in their acylation patterns. The structural assignment was achieved through extensive chemical analysis and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. Moreover, cellular immunology studies on the LPS highlighted its low immunostimulatory impact, as well as a very interesting and promising inhibitory activity of the toxic effects of Escherichia coli LPS.


123) Halloysite nanotubes and thymol as photo protectors of biobased polyamide 11

G.Gorrasi, V.Bugatti, M.Ussia, R.Mendichi, D.Zampino, C.Puglisi, S.Carroccio

Polymer Degradation and Stability  152,  43-51  - 2018

The formulation of cost-effectiveness sustainable materials is extensively growing and becoming an attractive approach for both industrial and academic fields. In this context, the bio-based aliphatic polyamide 11 (PA11) has acquired significant interest as environmentally friendly thermoplastic option. In addition, its formulation with selected natural antioxidant and/or reinforced compounds through green processing methods, might improve physical and mechanical properties without sacrificing the intrinsic bio-based nature of the matrix. In this work, we have investigated and compared the photo-oxidative degradation processes occurring on PA11 composites based on thymol and halloysite nanotubes prepared by using ball-milling method. In particular, halloysite nanotubes were used as green nano-container of a natural antioxidant molecule, and reinforced nano-filler as well. Molecular and structural information of photo-exposed samples were obtained by using size exclusion chromatography (SEC) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Thermal and mechanical properties were also tested as well as thymol release. Data collected confirmed that PA11 filled with HNTs-Thymol nano-hybrid showed superior durability performance if compared to both pure PA11 and PA11 blend realized by simply adding thymol and HNTs to polymer matrix. Furthermore, we found that HNTs and thymol combined in the nano-hydrid form exhibited an active and synergic role to achieve a major photo stabilization of PA11 biocomposite, without sacrificing its mechanical properties.

graphical abstract



124) Freestanding photocatalytic materials based on 3D graphene and polyporphyrins

M.Ussia, E.Bruno, E.Spina, D.Vitalini, G.Pellegrino, F.Ruffino, V.Privitera, S.Carroccio

Scientific Reports  8  - 2018

A new concept in the formulation of hybrid nanostructured materials combining high quality graphene 3D supported by Nickel foam and polyporphyrins for visible light photocatalytic application is here reported. Our innovative approach involves the development of a freestanding device able to: i) offer a high surface area to bind the photosensitizers by π-π interactions, and ii) enhance stability and photocatalytic efficiency by using cyclic porphyrin polymers. For these purposes, homo- and co-polymerization reactions by using different porphyrin (free or zinc complexed) monomers were performed. The microscopic structures and morphology of graphene polymer nanocomposites were investigated by using Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Atomic Force Microscopy (AFM). Finally, photocatalytic activity under visible light irradiation of the obtained nanocomposites was tested, by using methylene blue (MB) as organic pollutant. The obtained data suggested that hindered cyclic polymeric structures stacked on graphene surface by non-covalent interactions, restrict the formation of non photoactive aggregates and, as a consequence, induce an enhancement of photocatalytic activity. Remarkably, our systems show a degradation efficiency in the visible-light range much higher than other similar devices containing nanoporphyrin units reported in literature.

graphical abstract



125) Mutation and Suppressor Analysis of the Essential Lipopolysaccharide Transport Protein LptA Reveals Strategies To Overcome Severe Outer Membrane Permeability Defects in Escherichia coli

F.A.Falchi, E.A.Maccagni, S.Puccio, C.Peanoe, C.De Castro, A.Palmigiano, D.Garozzo, A.M.Martorana, A.Polissi, G.Dehò, P.Sperandeo

Journal of Bacteriology  200(7),  e00487-17  - 2018

DOI: https://doi.org/10.1128/JB.00487-17
In Gram-negative bacteria, lipopolysaccharide (LPS) contributes to the robust permeability barrier of the outer membrane (OM), preventing the entry of toxic molecules, such as detergents and antibiotics. LPS is transported from the inner membrane (IM) to the OM by the Lpt multiprotein machinery. Defects in LPS transport compromise LPS assembly at the OM and result in increased antibiotic sensitivity. LptA is a key component of the Lpt machine that interacts with the IM protein LptC and chaperones LPS through the periplasm. We report here the construction of lptA41, a quadruple mutant in four conserved amino acids potentially involved in LPS or LptC binding. Although viable, the mutant displays increased sensitivity to several antibiotics (bacitracin, rifampin, and novobiocin) and the detergent SDS, suggesting that lptA41 affects LPS transport. Indeed, lptA41 is defective in Lpt complex assembly, and its lipid A carries modifications diagnostic of LPS transport defects. We also selected and characterized two phenotypic bacitracin-resistant suppressors of lptA41. One mutant, in which only bacitracin sensitivity is suppressed, harbors a small in-frame deletion in mlaA, which codes for an OM lipoprotein involved in maintaining OM asymmetry by reducing accumulation of phospholipids in the outer leaflet. The other mutant, in which bacitracin, rifampin, and SDS sensitivity is suppressed, harbors an additional amino acid substitution in LptA41 and a nonsense mutation in opgH, encoding a glycosyltransferase involved in periplasmic membrane-derived oligosaccharide synthesis. Characterization of the suppressor mutants highlights different strategies adopted by the cell to overcome OM defects caused by impaired LPS transport.


126) Hypoacylated LPS from Foodborne Pathogen Campylobacter jejuni Induces Moderate TLR4-Mediated Inflammatory Response in Murine Macrophages

K.V.Korneev, A.N.Kondakova, E.N.Sviriaeva, N.A.Mitkin, A.Palmigiano, A.A.Kruglov, G.B.Telegin, M.S.Drutskaya, L.Sturiale, D.Garozzo, S.A.Nedospasov, Y.A.Knirel, D.V.Kuprash

Frontiers in Cellular and Infection Microbiology  8,  Art. 58  - 2018

Toll-like receptor 4 (TLR4) initiates immune response against Gram-negative bacteria upon specific recognition of lipid A moiety of lipopolysaccharide (LPS), the major component of their cell wall. Some natural differences between LPS variants in their ability to interact with TLR4 may lead to either insufficient activation that may not prevent bacterial growth, or excessive activation which may lead to septic shock. In this study we evaluated the biological activity of LPS isolated from pathogenic strain of Campylobacter jejuni, the most widespread bacterial cause of foodborne diarrhea in humans. With the help of hydrophobic chromatography and MALDI-TOF mass spectrometry we showed that LPS from a C. jejuni strain O2A consists of both hexaacyl and tetraacyl forms. Since such hypoacylation can result in a reduced immune response in humans, we assessed the activity of LPS from C. jejuni in mouse macrophages by measuring its capacity to activate TLR4-mediated proinflammatory cytokine and chemokine production, as well as NFκB-dependent reporter gene transcription. Our data support the hypothesis that LPS acylation correlates with its bioactivity.


127) Quality aspects of fresh-cut ’long-storage tomato’ as affected by package, calcium chloride and storage time

C.Patanè, A.Malvuccio, A.Saita, P.Rizzarelli, M.Rapisarda, V.Rizzo, G.Muratore

International Journal of Food Science & Technology  53,  819-827  - 2018

In this research, some quality changes during storage at 4 °C were assessed in fresh-cut fruits of a ’long-storage tomato’ landrace, packaged in biocompostable materials (PLA Ingeo tray/NatureFlexTM film) or in conventional plastics (PET tray + polypropylene film). The effects of dipping in CaCl2 on the shelf-life extension were also assessed. Plants were cultivated both off-season (greenhouse) and in-season (open field). CO2 and O2 concentration, fruit weight loss, firmness, colour, microbial load were measured at 0, 4, 7, 12 days of storage. Headspace gas changes and fruit weight loss were minimised in conventional package. BIO package prevented water condensation, led to max 5% weight loss and made fruits less susceptible to spoilage. Dipping in CaCl2 induced better firmness, especially in biopackage. Off-season fruits had overall lower quality than in-season fruits; however, these may contribute to extend the production season, with interesting marketing implications for the agri-food industry.


128) Hyaluronan-based graft copolymers bearing aggregation-induced emission fluorogens

A.Cappelli, M.Paolino, A.Reale, V.Razzano, G.Grisci, G.Giuliani, A.Donati, C.Bonechi, S.Lamponi, R.Mendichi, S.Battiato, F.Samperi, F.Makovec, M.Licciardi, L.Depau, Ch.Botta

Royal Society of Chemistry  8,  5864-5881  - 2018

In order to develop a technology platform based on two natural compounds from biorenewable resources, a short series of hyaluronan (HA) copolymers grafted with propargylated ferulic acid (HA-FA-Pg) were designed and synthesized to show different grafting degree values and their optical properties were characterized in comparison with reference compounds containing the same ferulate fluorophore. Interestingly, these studies revealed that the ferulate fluorophore was quite sensitive to the restriction of intramolecular motion and its introduction into the rigid HA backbone, as in HA-FA-Pg graft copolymers, led to higher photoluminescence quantum yield values than those obtained with the isolated fluorophore. Thus, the propargyl groups of HA-FA-Pg derivatives were exploited in the coupling with oleic acid through a biocompatible nona(ethylene glycol) spacer as an example of the possible applications of this technology platform. The resulting HA-FA-NEG-OA materials showed self-assembling capabilities in aqueous environment. Furthermore, HA-FA-NEG-OA derivatives have been shown to interact with phospholipid bilayers both in liposomes and living cells, retaining their fluorogenic properties and showing a high degree of cytocompatibility and for this reason they were proposed as potential biocompatible self-assembled aggregates forming new materials for biomedical applications.

Figure:HA-FA-NEG-OA Aggregates



129) Strength, fracture and compression properties of gelatins by a new 3D printed tool

M.Rapisarda, G.Valenti, D.Carbone, P.Rizzarelli, G.Recca, S.La Carta, R.Paradisi, S.Finocchiaro

Journal of Food Engineering   220,  38-48  - 2018

A new test has been developed to determine gel strength and, at the same time, fracture and compression parameters. By using an especially designed probe and standard gelatin gels, we have set up a method to assess gel strength, the cut resistance, simulating a teaspoon, as well as food consistency and chewiness, just in one experiment. In particular, hydrogels of different Bloom degrees, ranging from 90 to 300, were prepared. Gel strength, fracture and compression properties of gelatins were evaluated by a new 3D printed device. A cylindrical-shaped tool and a concentric piston were obtained by means of 3D-printing technology and combined for a fracture/compression test. A device for the classical Bloom test was 3D printed and used for gel strength measurements to find a correlation parameter. The cylindrical-shaped tool has been designed in order to expose to the gelatin surface the same contact area of the classical Bloom probe. Additionally, the optimized test was applied to commercial edible gelatins. The influence of temperature and flavors on gelatin properties was investigated.

graphical abstract



130) Grafting of Hindered Phenol Groups onto Ethylene/ α-Olefin Copolymer by Nitroxide Radical Coupling

S.Coiai, F.Cicogna, C.Yang, V.Tempesti, S.Carroccio, G.Gorrasi, R.Mendichi, N.Tz.Dintcheva, E.Passaglia

Polymers  9(12),  670  - 2017

The covalent immobilization of hindered phenol groups, with potential antioxidant activity, onto an ethylene/ α-olefin (EOC) copolymer was carried out by the nitroxide radical coupling (NRC) reaction performed in the melt with a peroxide and the 3,5-di-tert-butyl-4-hydroxybenzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (BHB-T). Functionalized EOC (EOC-g-(BHB-T)) was exposed to photo- and thermo-oxidation. By comparison with some model compounds bearing the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) moiety or the hindered phenol unit, it was observed that the grafted BHB-T could effectively help the stabilization of the polymer matrix both under photo- and thermo-oxidation. In addition, the immobilization of BHB-T can effectively increase the service life of the functionalized polymers when polymer films were put in contact with ethanol solution thus simulating a possible application of the modified polymer.

IPCB graphical abstract



131) Phenolic Fingerprint of Sicilian Modern Cultivars and Durum Wheat Landraces: A Tool to Assess Biodiversity

M.Lo Bianco, L.Siracusa, S.Dattilo, G.Venora, G.Ruberto

Cereal Chemistry  94(6),  1045-1051  - 2017

Durum wheat landraces have been recognized to have different contents in health-promoting phytochemicals. These health benefits have been mainly attributed to the presence of phenolic acids and flavonoids existing in this matrix both as soluble free compounds and insoluble bound forms. Sicily is one of the few areas of Southern Europe where it is still possible to find landraces of durum wheat, no longer cropped because of the commercial spread of new high-yielding varieties. This study aimed to determine the phenolic profile and content of 10 wheat landraces and three genetically improved cultivars to develop an analytical tool for cultivar screening and traceability. Hydroalcoholic extracts from wheat grains were analyzed by means of HPLC with a diode-array detector and HPLC electrospray ionization MS, revealing 13 metabolites belonging mainly to the classes of hydroxycinnamic acids and flavones C-glycosides. The quantitative pattern of the 13 phenolic markers, analyzed by applying stepwise linear discriminant analysis, allowed the discrimination between the two groups under study, namely, modern cultivars and durum wheat landraces. Furthermore, all 13 durum wheat varieties were perfectly discriminated in this statistical model, confirming a specific and genotype-dependent pattern of phenolics concentration.


132) New Water Based Drug Delivery System for Azithromycin Eye drops (MDV1226). PK Study in Rats vs Oily Azyter

B.Melilli, M.G.Saita, D.Aleo, S.Dattilo, S.Mangiafico, M.Cro

Investigative ophthalmology & visual science  58(8),  1087  - 2017



133) Sugar and mineral enriched fraction from olive mill wastewater for promising cosmeceutical application: characterization, in vitro and in vivo studies

M.D.Di Mauro, B.Tomasello, R.C.Giardina, S.Dattilo, V.Mazzei, F.Sinatra, M.Caruso, N.D’Antona, M.Renis

Food and Function  8,  4713-4722  - 2017

Nowadays, agro-food by-products represent a potential low-cost source of biologically active ingredients which have been paid significant attention as nutraceuticals, medicine, food and cosmetics. In a previous study we evaluated the total sugars, metals and polyphenols of olive mill wastewater (OMWW) from a Cerasuola olive cultivar. In the present work we selectively recovered a sugar and mineral enriched fraction (SMEF) from Cerasuola OMWW by a green adsorption/desorption process. The SMEF was mainly found to be composed of monosaccharides and potassium by HPLC-ELSD and ICP-MS. The in vitro cytotoxicity on human fibroblasts, at different concentrations of the fraction, was investigated by MTT and comet assays. In addition, intracellular reactive oxygen species (ROS) production, apoptosis and cell morphological changes were examined. The physical stability of a formulation containing the SMEF (1% w/w) and its in vivo skin effects were also assessed.Our results highlighted that the SMEF showed a toxic effect at higher concentrations (i.e. cell viability reduction, DNA fragmentation and morphological alterations) well correlated with high ROS levels. Conversely, at low concentrations (0.5% and 1% w/w), no significant changes were observed. For the first time, through stability studies and in vivo tests, we also demonstrated that the SMEF formulation is stable and safe for topical application, since skin hydration improvement without negative effects was observed after 7 days of its use. Therefore, the SMEF has great potential to be used for cosmeceutical applications.

IPCB graphical abstract



134) The lipopolysaccharide core oligosaccharide of Burkholderia plays a critical role in maintaining a proper gut symbiosis with the bean bug Riptortus pedestris

J.K.Kim, H.A.Jang, M.S.Kim, J.H.Cho, J.Lee, F.Di Lorenzo, L.Sturiale, A.Silipo, A.Molinaro, B.L.Lee

Journal of Biological Chemistry  292,  19226  - 2017

Lipopolysaccharide, the outer cell-wall component of Gram-negative bacteria, has been shown to be important for symbiotic associations. We recently reported that the lipopolysaccharide O-antigen of Burkholderia enhances the initial colonization of the midgut of the bean bug, Riptortus pedestris. However, the midgut-colonizing Burkholderia symbionts lack the O-antigen but display the core oligosaccharide on the cell surface. In this study, we investigated the role of the core oligosaccharide, which directly interacts with the host midgut, in the Riptortus-Burkholderia symbiosis. To this end, we generated the core oligosaccharide mutant strains, ΔwabS, ΔwabO, ΔwaaF, and ΔwaaC, and determined the chemical structures of their oligosaccharides, which exhibited different compositions. The symbiotic properties of these mutant strains were compared with those of the wild-type and O-antigen?deficient ΔwbiG strains. Upon introduction into Riptortus via the oral route, the core oligosaccharide mutant strains exhibited different rates of colonization of the insect midgut. The symbiont titers in fifth-instar insects revealed significantly reduced population sizes of the inner core oligosaccharide mutant strains ΔwaaF and ΔwaaC. These two strains also negatively affected host growth rate and fitness. Furthermore, R. pedestris individuals colonized with the ΔwaaF and ΔwaaC strains were vulnerable to septic bacterial challenge, similar to insects without a Burkholderia symbiont. Taken together, these results suggest that the core oligosaccharide from Burkholderia symbionts plays a critical role in maintaining a proper symbiont population and in supporting the beneficial effects of the symbiont on its host in the Riptortus-Burkholderia symbiosis.


135) Polylactide/lignin blends

G.Cicala, G.Saccullo, I.Blanco, S.Samal, S.Battiato, S.Dattilo, B.Saake

Journal of Thermal Analysis and Calorimetry  130(1),  512-524  - 2017

The effect of processing temperature and time on polylactide/lignin blends was evaluated. Two blends, one commercial and one prepared mixing polylactide (PLA) with different lignin contents, were processed at 190 and 170 °C for different mixing times. The commercial blend was a blend of PLA with 5 mass% of soda lignin and 15.4 mass% of softwood while, for the laboratory-made PLA/lignin, the content of lignin varied from 10 to 25 mass%. Both the blends showed significant degradation of the mechanical properties when processed at 190 °C. The use of lower processing temperature (i.e., 170 °C) showed minor degradation on both the blends. The lignin content showed a marked effect on the degradation behavior of the blends for all the processing temperatures tested.


136) Carbon source effects on the mono/dirhamnolipid ratio produced by Pseudomonas aeruginosa L05, a new human respiratory isolate

M.S.Nicolò, M.G.Cambria, G.Impallomeni, M.G.Rizzo, C.Pellicorio, A.Ballistreri, S.P.P.Guglielmino

New Biotechnology   39 part A,  36-41  - 2017

Pseudomonas strains produce rhamnolipid mixtures (RLs) that generally consist of one or two molecules of rhamnose linked to one or two molecules of 3-hydroxyalkanoic acid. This study evaluates carbon source effects (glycerol, glucose, myristic acid, and Brassica carinata oil) on the synthesis of monorhamnolipids (mono-RLs) versus dirhamnolipids (di-RLs) in a human isolate of Pseudomonas aeruginosa PAL05. Spectrophotometry, an emulsifying index (E24) test, and an orcinol assay confirmed the production of RLs by PAL05. Purified RLs were characterized by 1H NMR analysis. PAL05 primarily produces mono-RLs when provided carbon sources containing long chain fatty acids (FAs) (myristic acid and B. carinata oil) and di-RLs when provided glycerol or glucose. qRT-PCR analysis showed that delayed expression of rhlC occurred when B. carinata oil was used, but not glycerol, glucose, or myristic acid. Our data show that the carbon source influenced the transcriptional expression of the rhlC gene and, consequently, the predominance of mono-RLs or di-RLs in PAL05 cultures.


137) Orientation behavior is a good biomarker of trace metal contamination in Parallelomorphus laevigatus (Coleoptera, Carabidae)

E.Conti, S.Dattilo, G.Costa, C.Puglisi

Environmental Science and Pollution Research  24(21),  17642-17650  - 2017

Behavioral ecotoxicology has become very important in the short time since a change in behavior is very often the first response to environmental altered conditions. We investigated the influence of trace metal intake on the spatial orientation performances of the carabid beetle Parallelomorphus laevigatus, fundamental ability for its survival. The aim of this study was to consider the solar orientation as behavioral biomarker for exposure to trace metal contamination. Therefore, we tested the ability of solar orientation of specimens of this species, fed with shrimps contaminated with three different concentrations of Cu, Zn, or Hg. We carried out the orientation tests after 1, 3, 7, and 10 days of contaminated feeding. Subsequently, we fed these beetles with not contaminated shrimps and again tested them after 1, 3, 7, and 10 days. For all three metals considered and, regardless of the degree of contamination of the food, we have found a progressive and significant counterclockwise displacement of the angle of orientation and a corresponding progressive reduction in the precision in the directional choices by the animals. We also noticed a clear growing recovery in the normal orientation by these insects after returning to their feeding with uncontaminated food. In conclusion, we can consider the orientation in space of P. laevigatus as a behavioral biomarker for exposure to trace metal contamination. We believe that the intake of trace metals may induce the insects to make mistakes in their spatial orientation, due to an acceleration of their biological clock. Such a clock malfunction is not definitive, since the return to a normal diet restores P. laevigatus the ability to re-make the correct directional choices. Ultimately, our results confirm the usefulness of behavioral ecotoxicology investigations; moreover, they stimulate the opportunity to deepen the understanding of functioning of the biological clock in the animals.


138) Investigation on Structure and Thermomechanical Processing of Biobased Polymer Blends

G.Cicala, A.Latteri, G.Saccullo, G.Recca, L.Sciortino, S.Lebioda, B.Saake

Journal of Polymers and the Environment  25(3),  750-758  - 2017

The structure and composition of a biobased polymer blend with wood like appearance was studied. The effects of processing time for mixing at 190 °C was investigated. The structure of the blend was unveiled combining fractionation techniques with size exclusion chromatography and nuclear magnetic resonance analysis. The material was found to be a blend of polylactide (PLA) polymer with 15.4 wt% ground softwood and 5 wt% soda lignin. The findings about composition supported the explanation of the thermal behavior and the processing stability analysis. The blend showed tensile properties degradation after mixing at 190 °C for 25 min. The ultimate tensile strength dropped from 29.75 to 4.85 MPa while the tensile modulus dropped from 5.3 to 4.2 GPa. The degradation behavior was explained in terms of the PLA degradation enhanced by the presence of the natural constituents in the blend.


139) The Very Long Chain Fatty Acid (C26:25OH) Linked to the Lipid A Is Important for the Fitness of the Photosynthetic Bradyrhizobium Strain ORS278 and the Establishment of a Successful Symbiosis with Aeschynomene Legumes

N.Busset, F.Di Lorenzo, A.Palmigiano, L.Sturiale, F.Gressent, J.Fardoux, D.Gully, C.Chaintreuil, A.Molinaro, A.Silipo, E.Giraud

Frontiers in Microbiology  8,  201  - 2017

In rhizobium strains, the lipid A is modified by the addition of a very long-chain fatty acid (VLCFA) shown to play an important role in rigidification of the outer membrane, thereby facilitating their dual life cycle, outside and inside the plant. In Bradyrhizobium strains, the lipid A is more complex with the presence of at least two VLCFAs, one covalently linked to a hopanoid molecule, but the importance of these modifications is not well-understood. In this study, we identified a cluster of VLCFA genes in the photosynthetic Bradyrhizobium strain ORS278, which nodulates Aeschynomene plants in a Nod factor-independent process. We tried to mutate the different genes of the VLCFA gene cluster to prevent the synthesis of the VLCFAs, but only one mutant in the lpxXL gene encoding an acyltransferase was obtained. Structural analysis of the lipid A showed that LpxXL is involved in the transfer of the C26:25OH VLCFA to the lipid A but not in the one of the C30:29OH VLCFA which harbors the hopanoid molecule. Despite maintaining the second VLCFA, the ability of the mutant to cope with various stresses (low pH, high temperature, high osmolarity, and antimicrobial peptides) and to establish an efficient nitrogen-fixing symbiosis was drastically reduced. In parallel, we investigated whether the BRADO0045 gene, which encodes a putative acyltransferase displaying a weak identity with the apo-lipoprotein N-acyltransferase Lnt, could be involved in the transfer of the C30:29OH VLCFA to the lipid A. Although the mutant exhibited phenotypes similar to the lpxXL mutant, no difference in the lipid A structure was observed from that in the wild-type strain, indicating that this gene is not involved in the modification of lipid A. Our results advance our knowledge of the biosynthesis pathway and the role of VLCFAs-modified lipid A in free-living and symbiotic states of Bradyrhizobium strains.


140) Effect of different anti-browning agents on quality of minimally processed early potatoes packaged on a compostable film

A.Ierna, P.Rizzarelli, M.Rapisarda

LWT- Food Science and Technology  85,  434-439  - 2017

Nowadays, there is a growing interest in bio-based compostable packaging also for fresh fruits and vegetables. We evaluated the influence of two different packaging: a bio-based compostable film (BIO) and a conventional coextruded polyamide/polyethylene (CONV), combined with 3 anti-browning solutions (sterile water - SW, 0.2 g kg-1 sodium bisulphite - SB; 20 g kg-1 ascorbic acid + 20 g kg-1 citric acid - AA + CA) on the physico-chemical and microbiological traits of minimally processed potatoes of cvs. ’Bellini’ and ’Marabel’ during storage at 4 °C for 9 days. Preliminary results showed that the BIO film was less suitable to guarantee quality (i.e., higher browning, fresh weight loss and microbial growth) of minimally processed potato tubers than CONV film. This result was reasonably related to the drastically modified barrier properties of compostable polymeric film by migration of water from potatoes, more markedly in ’Bellini’ than in ’Marabel’ cultivar. Dipping in AA + CA solution allowed containing microbial growth during whole storage time, more efficiently in CONV than in BIO bags.


141) Neuraminidases 3 and 4 regulate neuronal function by catabolizing brain gangliosides

X.Pan, C.B.P.De Aragão, J.P.Velasco-Martin, D.A.Priestman, H.Y.Wu, K.Takahashi, K.Yamaguchi, L.Sturiale, D.Garozzo, F.M.Platt, N.Lamarche-Vane, C.R.Morales, T.Miyagi, A.V.Pshezhetsky

FASEB J.  31,  3467-3483  - 2017

Gangliosides (sialylated glycolipids) play an essential role in the CNS by regulating recognition and signaling in neurons. Metabolic blocks in processing and catabolism of gangliosides result in the development of severe neurologic disorders, including gangliosidoses manifesting with neurodegeneration and neuroinflammation. We demonstrate that 2 mammalian enzymes, neuraminidases 3 and 4, play important roles in catabolic processing of brain gangliosides by cleaving terminal sialic acid residues in their glycan chains. In neuraminidase 3 and 4 double-knockout mice, GM3 ganglioside is stored in microglia, vascular pericytes, and neurons, causing micro- and astrogliosis, neuroinflammation, accumulation of lipofuscin bodies, and memory loss, whereas their cortical and hippocampal neurons have lower rate of neuritogenesis in vitro Double-knockout mice also have reduced levels of GM1 ganglioside and myelin in neuronal axons. Furthermore, neuraminidase 3 deficiency drastically increased storage of GM2 in the brain tissues of an asymptomatic mouse model of Tay-Sachs disease, a severe human gangliosidosis, indicating that this enzyme is responsible for the metabolic bypass of β-hexosaminidase A deficiency. Together, our results provide the first in vivo evidence that neuraminidases 3 and 4 have important roles in CNS function by catabolizing gangliosides and preventing their storage in lipofuscin bodies


142) Structure of the Lipopolysaccharide from the Bradyrhizobium sp. ORS285 rfaL Mutant Strain

F.Di Lorenzo, A.Palmigiano, K.A.Duda, M.Pallach, N.Busset, L.Sturiale, E.Giraud, D.Garozzo, A.Molinaro, A.Silipo

ChemistryOpen  6,  541-553  - 2017

The importance of the outer membrane and of its main constituent, lipopolysaccharide, in the symbiosis between rhizobia and leguminous host plants has been well studied. Here, the first complete structural characterization of the entire lipopolysaccharide from an O-chain-deficient Bradyrhizobium ORS285 rfaL mutant is achieved by a combination of chemical analysis, NMR spectroscopy, MALDI MS and MS/MS. The lipid A structure is shown to be consistent with previously reported Bradyrhizobium lipid A, that is, a heterogeneous blend of penta- to hepta-acylated species carrying a nonstoichiometric hopanoid unit and possessing very-long-chain fatty acids ranging from 26:0(25-OH) to 32:0(31-OH). The structure of the core oligosaccharide region, fully characterized for the first time here, is revealed to be a nonphosphorylated linear chain with methylated sugar residues, with a heptose residue exclusively present in the outer core region, and with the presence of two singly substituted 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) residues, one of which is located in the outer core region. The lipid A moiety is linked to the core moiety through an uncommon 4-substituted Kdo unit.

graphical abstract



143) The Deep-Sea Polyextremophile Halobacteroides lacunaris TB21 Rough-Type LPS: Structure and Inhibitory Activity towards Toxic LPS

F.D.Lorenzo, A.Palmigiano, I.Paciello, M.Pallach, D.Garozzo, M.L.Bernardini, V.Cono, M.M.Yakimov, A.Molinaro, A.Silipo

Marine Drugs  15(7),  201  - 2017

The structural characterization of the lipopolysaccharide (LPS) from extremophiles has important implications in several biomedical and therapeutic applications. The polyextremophile Gram-negative bacterium Halobacteroides lacunaris TB21, isolated from one of the most extreme habitats on our planet, the deep-sea hypersaline anoxic basin Thetis, represents a fascinating microorganism to investigate in terms of its LPS component. Here we report the elucidation of the full structure of the R-type LPS isolated from H. lacunaris TB21 that was attained through a multi-technique approach comprising chemical analyses, NMR spectroscopy, and Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry. Furthermore, cellular immunology studies were executed on the pure R-LPS revealing a very interesting effect on human innate immunity as an inhibitor of the toxic Escherichia coli LPS.


144) Controlled and Sustained Release of a Corticosteroid Drug From Block Copolymers Synthetized by ATRP

G.Valenti, S.La Carta, G.Mazzotti, M.Rapisarda, S.Perna, R.Di Gesù, L.Giorgini, D.Carbone, G.Recca, P.Rizzarelli

Polymer Engineering and Science   2017,  570-578  - 2017

During last decades, implantable drug delivery systems (DDS) have been developed to optimize therapeutic properties of drugs and ensure their release in a specific site. Acrylic polymers have obtained growing interest in biomedical applications for their biocompatibility and chemical properties that make them extremely versatile. In this work, we focused on the realization of polymeric systems for controlled and sustained release of betamethasone 17,21-dipropionate (BDP), a corticosteroid drug, in the treatment of the posterior eye diseases (PED). The investigated DDS were made of opportunely designed methacrylic block copolymers. Different series of methylmethacrylate/2-hydroxyethylmethacrylate (MMA/HEMA) block copolymers, with various monomeric compositions (20-60 mol % HEMA), were synthetized by Atom Transfer Radical Polymerization (ATRP) to find the best hydrophilic/hydrophobic ratio, able to ensure optimal kinetic release. Copolymers were characterized by NMR, SEC and DSC. Monitoring of drug release from films loaded with BDP was carried out by HPLC analysis. In particular, PMMA-b-PHEMA with 47 mol % of HEMA showed the best release profile to achieve the therapeutic reference dose, employed in the treatment of PED (1-3 μg/day), up to four months. Additionally, intraocular inserts with different shapes were prepared using silicon molds made by means of a 3D printer.


145) MALDI-MS profiling of serum O-glycosylation and N-glycosylation in COG5-CDG

A.Palmigiano, R.O.Bua, R.Barone, D.Rymen, L. Régal, N.Deconinck, C.Dionisi-Vici, C.W.Fung, D.Garozzo, J.Jaeken, L.Sturiale

Journal of Mass Spectrometry  52(6),  372-377  - 2017

DOI: https://doi.org/10.1002/jms.3936
Congenital disorders of glycosylation (CDG) are due to defective glycosylation of glycoconjugates. Conserved oligomeric Golgi (COG)-CDG are genetic diseases due to defects of the COG complex subunits 1-8 causing N-glycan and O-glycan processing abnormalities. In COG-CDG, isoelectric focusing separation of undersialylated glycoforms of serum transferrin and apolipoprotein C-III (apoC-III) allows to detect N-glycosylation and O-glycosylation defects, respectively. COG5-CDG (COG5 subunit deficiency) is a multisystem disease with dysmorphic features, intellectual disability of variable degree, seizures, acquired microcephaly, sensory defects and autistic behavior. We applied matrix-assisted laser desorption/ionization-MS for a high-throughput screening of differential serum O-glycoform and N-glycoform in five patients with COG5-CDG. When compared with age-matched controls, COG5-CDG showed a significant increase of apoC-III0a (aglycosylated glycoform), whereas apoC-III1 (mono-sialylated glycoform) decreased significantly. Serum N-glycome of COG5-CDG patients was characterized by the relative abundance of undersialylated and undergalactosylated biantennary and triantennary glycans as well as slight increase of high-mannose structures and hybrid glycans. Using advanced and well-established MS-based approaches, the present findings reveal novel aspects on O-glycan and N-glycan profiling in COG5-CDG patients, thus providing an increase of current knowledge on glycosylation defects caused by impairment of COG subunits, in support of clinical diagnosis.

graphical abstract



146) The ground beetle Parallelomorphus laevigatus is a potential indicator of trace metal contamination on the eastern coast of Sicily

E.Conti, S.Dattilo, G.Costa, C.Puglisi

Ecotoxicology and Environmental Safety  135,  183-190  - 2017

Carabids are generally considered to be non-specialized predators, and they have been considered useful ecological indicators. They can play a key role in clarifying the route of contaminants in food webs because they are predators of small invertebrates and, in turn, part of the diet of several vertebrates. The Mediterranean species Parallelomorphus laevigatus, which so far has not been studied from an ecotoxicological point of view, is an excellent ecological indicator in sandy coastal environments. We investigated the accumulation of trace elements in Ionian populations of P. laevigatus and evaluated the transfer of metal through the food chain of the coastal ecosystem. We analyzed 15 metals, including 11 essential metals (Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Sn, V and Zn) and four toxic metals (As, Cd, Hg and Pb). Significant differences were found in metal concentration in animal tissues among sites. Our results support the existence of defense mechanisms for the studied species. High values of As, Cd, Cr, Pb, Ni, and Hg detected in the beetles from the control site can be explained by both the emission sources from the nearby industrial plants and the intense agricultural activity. The present paper shows increasing Hg concentrations in the simplified trophic web of sandy beaches and confirms the capability of this pollutant to biomagnify. Moreover, the high value of biomagnification factor (BMF) points to the severe pollution level in this protected area.


147) Engineering thermoplastics for additive manufacturing: a critical perspective with experimental evidence to support functional applications

G.Cicala, A.Latteri, B.Del Curto, A.Lo Russo, G.Recca, S.Farè

Journal of Applied Biomaterials & Functional Materials   15(1),  10-18  - 2017

BACKGROUND: Among additive manufacturing techniques, the filament-based technique involves what is referred to as fused deposition modeling (FDM). FDM materials are currently limited to a selected number of polymers. The present study focused on investigating the potential of using high-end engineering polymers in FDM. In addition, a critical review of the materials available on the market compared with those studied here was completed.
METHODS: Different engineering thermoplastics, ranging from industrial grade polycarbonates to novel polyetheretherketones (PEEKs), were processed by FDM. Prior to this, for innovative filaments based on PEEK, extrusion processing was carried out. Mechanical properties (i.e., tensile and flexural) were investigated for each extruded material. An industrial-type FDM machine (Stratasys Fortus® 400 mc) was used to fully characterize the effect of printing parameters on the mechanical properties of polycarbonate. The obtained properties were compared with samples obtained by injection molding. Finally, FDM samples made of PEEK were also characterized and compared with those obtained by injection molding.
RESULTS: The effect of raster to raster air gap and raster angle on tensile and flexural properties of printed PC was evidenced; the potential of PEEK filaments, as novel FDM material, was highlighted in comparison to state of the art materials.
CONCLUSIONS: Comparison with injection molded parts allowed to better understand FDM potential for functional applications. The study discussed pros and cons of the different materials. Finally, the development of novel PEEK filaments achieved important results offering a novel solution to the market when high mechanical and thermal properties are required.


148) Concentration-dependent anti-/pro-oxidant activity of natural phenolic compounds in bio-polyesters

N.T.Dintcheva, R.Arrigo, M.Baiamonte, P.Rizzarelli, G.Curcuruto

Polymer Degradation and Stability  142,  21-28  - 2017

In this work, the potential of several naturally occurring phenolic compounds, such as Ferulic Acid (FA), Vanillic Acid (VA), Vitamin E (VE) and Quercetin (Q), as stabilizers against the photo-oxidative degradation of Polylactic acid (PLA) has been assessed. Specifically, PLA-based films containing different amounts of considered stabilizers have been formulated and their photo-stability under UVB exposure has been evaluated. The preliminary characterization of the formulated films shows that all used stabilizers exert plasticizing action, as probed by rheological analysis, due to their low molecular weight. Moreover, no significant modification of the PLA crystallinity has been noticed in presence of used natural compounds. The study of the photo-oxidation behaviour of PLA-based systems suggests that, among all used natural phenolic compounds, FA and Q are suitable anti-oxidant for PLA, if they are added at low content. Surprisingly, all considered natural compounds, exert a pronounced pro-degradant action in PLA matrix, if their content overcomes a certain specific threshold. This finding has been related to the known concentration-dependent anti-/pro-oxidant activity of used phenolic compounds, that results exacerbated in presence of traces of transition metals, such as iron and copper.


149) Xanthomonas citri pv. citri Pathotypes: LPS Structure and Function as Microbe-Associated Molecular Patterns

F.Di Lorenzo, A.Silipo, L.B. Andersen Gersby, A.Palmigiano, R.Lanzetta, D.Garozzo, C.Boyer, O.Pruvost, M.Newman, A.Molinaro

ChemBioChem  18(8),  772-781  - 2017

Xanthomonas citri pv. citri is the pathogen responsible for Asiatic citrus canker, one of the most serious citrus diseases worldwide. The lipopolysaccharide (LPS) molecule has been demonstrated to be involved in X. citri pv. citri virulence. Despite enormous progress in investigations of the molecular mechanisms for bacterial pathogenicity, determination of the detailed LPS structure-activity relationship is limited, as the current knowledge is mainly based on structural determination of one X. citri pv. citri strain. As X. citri pv. citri strains are distinguished into three main pathogenicity groups, we characterized the full structure of the LPS from two pathotypes that differ in their host-range specificity. This revealed an intriguing difference in LPS O-chain structure. We also tested the LPSs and isolated lipid A moieties for their ability to act as microbe-associated molecular patterns in Arabidopsis thaliana. Both LPS/lipid As induced ROS accumulation, but no difference was observed between the two pathotypes.


150) Recessive mutations in SLC35A3 cause early onset epileptic encephalopathy with skeletal defects

C.Marini, K.Hardies, T.Pisano, P.May, S.Weckhuysen, E.Cellini, A.Suls, D.Mei, R.Balling, P.D.Jonghe, I.Helbig, D.Garozzo, EuroEpiNOMICS, R.Guerrini

American Journal of Medical Genetics Part A  173(4),  1119-1123  - 2017

We describe the clinical and whole genome sequencing (WGS) study of a non-consanguineous Italian family in which two siblings, a boy and a girl, manifesting a severe epileptic encephalopathy (EE) with skeletal abnormalities, carried novel SLC35A3 compound heterozygous mutations. Both siblings exhibited infantile spasms, associated with focal, and tonic vibratory seizures from early infancy. EEG recordings showed a suppression-burst (SB) pattern and multifocal paroxysmal activity in both. In addition both had quadriplegia, acquired microcephaly, and severe intellectual disability. General examination showed distal arthrogryposis predominant in the hands in both siblings and severe left dorso-lumbar convex scoliosis in one. WGS of the siblings-parents quartet identified novel compound heterozygous mutations in SLC35A3 in both children. SLC35A3 encodes the major Golgi uridine diphosphate N-acetylglucosamine transporter. With this study, we add SLC35A3 to the gene list of epilepsies. Neurological symptoms and skeletal abnormalities might result from impaired glycosylation of proteins involved in normal development and function of the central nervous system and skeletal apparatus.


151) The Lipid A from Rhodopseudomonas palustris Strain BisA53 LPS Possesses a Unique Structure and Low Immunostimulant Properties

F.Di Lorenzo, A.Palmigiano, S.Al Bitar-Nehme, L.Sturiale, K.A.Duda, D.Gully, R.Lanzetta, E.Giraud, D.Garozzo, M.L.Bernardini, A.Molinaro, A.Silipo

Chemistry A European Journal  23(15),  3637-3647  - 2017

The search for novel lipid A analogues from any biological source that can act as antagonists, displaying inhibitory activity towards the production of pro-inflammatory cytokines, or as immunomodulators in mammals, is a very topical issue. To this aim, the structure and immunological properties of the lipopolysaccharide lipid A from the purple nonsulfur bacterium Rhodopseudomonas palustris strain BisA53 have been determined. This lipid A displays a unique structural feature, with a non-phosphorylated skeleton made up of the tetrasaccharide Manρ-α-(1→4)-GlcρN3N-β-1→6-GlcρN3N-α-(1→1)-α-GalρA, and four primary amide-linked 14:0(3-OH) and, as secondary O-acyl substituents, a 16:0 and the very long-chain fatty acid 26:0(25-OAc), appended on the GlcρN3N units. This lipid A architecture is definitely rare, so far identified only in the genus Bradyrhizobium. Immunological tests on both murine bone-marrow-derived and human monocyte-derived macrophages revealed an extremely low immunostimulant capability of this LPS lipid A.

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152) SHELF LIFE EVALUATION OF FRESH-CUT GLOBE ARTICHOKE PACKAGED IN A COMPOSTABLE BIOBASED FILM

V.Rizzo, G.Sapienza, C.Restuccia, G.Mauromicale, S.Lombardo, G.R.Pesce, M.Rapisarda, S.Perna, P.Rizzarelli, G.Muratore

Italian Journal of Food Science  28,  7-12  - 2016

Globe artichoke is an important component in the Mediterranean diet, but its complexity of preparation and susceptibility to browning degree limit its consumption on a wider scale. Therefore, the aim of the present study was to propose on the one hand, a suitable processing to obtain fresh-cut globe artichoke heads using active compounds to delay browning and, on the other hand, the best packaging solution to reduce water loss. Ascorbic and citric acids were used asanti-browning agents and two different packaging solutions were tested. Heads were divided into homogeneous lots of 50 heads, and after the processing slices were placed in PET trays and packed in ordinary atmosphere using a Cast Polypropylene film and NatureFlexTM compostable BIObased film. Bags were hermetically sealed and stored at 4 °C for 14 days. Analysis of weight losses, texture, respiration rate, colour degradation, polyphenol and ascorbic acid content and microbiological analysis were performed. Our results highlighted as cv. Spinoso sardo proved to have suitable qualitative characteristics for industrial processing; both packaging films used ensured a prolonging of shelf life that seems to be enough for produce distribution to the local markets.


153) Micro-optofluidic switch realized by 3D printing technology

F.Cairone, S.Gagliano, D.Carbone, G.Recca, M.Bucolo

Microfluidics and Nanofluidics  20(4),  1-10  - 2016

This paper presents a PDMS micro-optofluidic chip that allows a laser beam to be driven directly toward a two-phase flow stream in a micro-channel while at the same time automatically, detecting the slug’s passage and stirring the laser light, without the use of any external optical devices. When the laser beam interacts with the microfluidic flow, depending on the fluid in the channel and the laser angle of incidence, a different signal level is detected. So a continuous air-water segmented flow will generate a signal that switches between two values. The device consists of a T-junction, which generates the two-phase flow, and three optical fiber insertions, which drive the input laser beam toward a selected area of the micro-channel and detects the flow stream. Three micro-channel sections of different widths were considered: 130, 250, 420 µm and the performance of the models was obtained by comparing ray-tracing simulations. The master of the device has been realized by 3D printing technology and a protocol which realizes the PDMS chip is presented. The static and dynamic characterizations, considering both single flows and two-phase flows, were carried out, and in spite of the device’s design simplicity, the sensitivity of the system to capture changes in the segmented flows and to stir the laser light in different directions was fully confirmed. The experimental tests show the possibility of obtaining satisfactory results with channel diameters in the order of 200 µm.


154) Bioaccumulation of trace elements in the sandhopper Talitrus saltator (Montagu) from the Ionian sandy coasts of Sicily

E.Conti, S.Dattilo, G.Costa, C.Puglisi

Ecotoxicology and Environmental Safety  129,  57-66  - 2016

The Ionian beaches of Sicily are of particular ecological interest because they include the basin of the largest active volcano in Europe and hosts both sites subject to natural protection constraints, as well as important industrial settlements. Consequently, the possibilities for these areas to become polluted are numerous. The sandhopper Talitrus saltator has proven to be a good bioindicator of contamination by numerous trace metals on some European coasts. Nevertheless, no data are available for the populations inhabiting the shores of the southern Mediterranean. Now, as metal accumulation has been shown to vary intraspecifically, the aim of this study was to evaluate trace metal accumulation in adults of T. saltator inhabiting Ionian coastal areas of Sicily and make an assessment of natural and anthropogenic metal pollution of this strip of coast. We also extended our survey to As, Co, Mo, Se, Sn and V never investigated before in this species. Significant differences in metal concentration among sites were found in both sand samples and amphipod tissues. The highest metal content was observed near the mouth of Simeto, the longest river of Sicily which collects waters coming from the volcanic territory of Mount Etna. The bioaccumulation of Cd, Cu, Hg and Zn in T. saltator is fully confirmed; it is also proven for As and Mo and assumed for Cr, Fe, Mn and V. Our outcomes let us to evaluate the prevailing influence of telluric contamination of the Ionian sandy shores of Sicily by trace metals. We also come to the conclusion that in the northern sites, pollution originates from volcanic emission while anthropogenic influence prevails in the southern ones.


155) Poly-paper: a sustainable material for packaging, based on recycled paper and recyclable with paper

N.Barelli, B.Del Curto, S.Farè, A.Cigada, M.C.Tanzi, G.Cicala, M.Profaizer, G.Ognibene, G.Recca

Journal of Applied Biomaterials & Functional Materials   14(4),  490-495  - 2016

BACKGROUND: Until now, environmental sustainability issues are almost entirely unsolved for packaging materials. With the final aim of finding materials with a single recycling channel, cellulose fiber/poly(vinyl)alcohol composites were investigated.

METHODS: After extrusion and injection molding, samples of composite with different cellulose fiber content (30%, 50% and 70% w/w) were tested.

RESULTS: Tensile mechanical tests exhibited an improvement in composite stiffness when the reinforcement content was increased together with a decrease in composite elongation. Solubility tests performed at room temperature and 45°C showed different behavior depending on the water-resistant film applied on the composite (50% cellulose fiber content). In particular, the uncoated composite showed complete solubility after 2 hours, whereas at the same time point, no solubility occurred when a non-water-soluble varnish was used.

CONCLUSIONS: The proposed composites, named Poly-paper, appear to warrant further investigation as highly sustainable packaging.


156) Investigation on Structure and Thermomechanical Processing of Biobased Polymer Blends

G.Cicala, A.Latteri, G.Saccullo, G.Recca, L.Sciortino, S.Lebioda, B.Saake

Journal of Polymers and the Environment  ,  1-9  - 2016

The structure and composition of a biobased polymer blend with wood like appearance was studied. The effects of processing time for mixing at 190 °C was investigated. The structure of the blend was unveiled combining fractionation techniques with size exclusion chromatography and nuclear magnetic resonance analysis. The material was found to be a blend of polylactide (PLA) polymer with 15.4 wt% ground softwood and 5 wt% soda lignin. The findings about composition supported the explanation of the thermal behavior and the processing stability analysis. The blend showed tensile properties degradation after mixing at 190 °C for 25 min. The ultimate tensile strength dropped from 29.75 to 4.85 MPa while the tensile modulus dropped from 5.3 to 4.2 GPa. The degradation behavior was explained in terms of the PLA degradation enhanced by the presence of the natural constituents in the blend.


157) Hyaluronan-coated polybenzofulvene brushes as biomimetic materials

A.Cappelli, M.Paolino, G.Grisci, V.Razzano, G.Giuliani, A.Donati, C.Bonechi, R.Mendichi, S.Battiato, F.Samperi, C.Scialabba, G.Giammona, F.Makovec, M.Licciardi

Polymer Chemistry  7,  6529-6544  - 2016

Hyaluronic acid (HA) forms pericellular coats in many cell types that are involved in the early stages of cell adhesion by interacting with the CD44 receptor. Based on the largely recognized overexpression of the CD44 receptor in tumor tissues, a polybenzofulvene molecular brush has been enveloped into hyaluronan shells to obtain a tri-component polymer brush (TCPB) composed of intrinsically fluorescent backbones bearing nona(ethylene glycol) arms terminated with low molecular weight HA macromolecules. The nanoaggregates obtained in TCPB water dispersions were characterized on the basis of dimensions, zeta potential, and in vitro cell toxicity. This biomimetic multifunctional material bearing HA on the surface of its cylindrical brush architecture showed promising prerequisites for the preparation of nanostructured drug delivery systems.

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158) Preparation of poly(glycolide-co-lactide)s through a green process: Analysis of structural, thermal, and barrier properties

G.Gorrasi, A.Meduri, P.Rizzarelli, S.Carroccio, G.Curcuruto, C.Pellecchia, D.Pappalardo

Reactive and Functional Polymers  109,  70-78  - 2016

We have successfully synthesized poly(lactide), poly(glycolide), and poly(lactide-co-glycolide) copolymers in bulk by ring-opening homo- and copolymerization of glycolide and L-lactide, using sodium hydride as the environmentally friendly and nontoxic initiator. Random copolymers were obtained, and the microstructure was characterized by nuclear magnetic resonance (1H and 13C NMR) and matrix-assisted laser desorption ionization mass spectrometry (MALDI MS). The mechanism of reaction was elucidated by analysis of the polymer end groups. Homopolymer and copolymers films and their blends were obtained, and structure and physical properties analyzed. Thermal degradation analysis showed superior characteristics of copolymers with respect to the blends. Transport properties of water vapor were also evaluated and correlated to the copolymer composition


159) Synthesis and characterization of new porphyrin/β-cyclodextrin derivatives covalently connected by aliphatic chains of different length

G.Mercorillo, R.Puglisi, E.Spina, D.Vitalini

Journal of Porphyrins and Phthalocyanines  20(6),  700-707  - 2016

Covalently linked porphyrin/β-cyclodextrin derivatives have been synthesized by reaction between 5,10,15-tris-{p-[9-methoxy-tris-(ethyleneoxy)-phenyl]}-20-(p-hydroxyphenyl)-porphyrin, β-cyclodextrin-6-alcoholate and di-brominated aliphatic chains of different length, and characterized by MALDI-TOF mass spectrometry, 1H NMR and UV-vis spectroscopy. As a function of chain length, these compounds exhibit different degrees of water solubility, becoming higher with increasing chain length. The lack of self-assemblies between porphyrins and β-cyclodextrins (which renders the two sub-units completely free to perform their activities) and their water solubility, make these compounds excellent candidates in fields like drug-delivery or photodynamic therapy.


160) Prevotella denticola Lipopolysaccharide from a Cystic Fibrosis Isolate Possesses a Unique Chemical Structure

F.Di Lorenzo, A.Silipo, Th.Matier, A.Hanuszkiewicz, J.S.Elborn, R.Lanzetta, L.Sturiale, A.Scamporrino, D.Garozzo, M.A.Valvano, M.M.Tunney, A.Molinaro

European Journal of Organic Chemistry  2016(9),  1732-1738  - 2016

We report the first complete structural characterization of the lipopolysaccharide (LPS) from a cystic fibrosis (CF) clinical isolate of Prevotella denticola (B003V1S1X). Chemical, spectroscopic, and spectrometric analyses revealed a unique rough-type LPS (LOS) structure. The structure has a highly negatively charged heptasaccharide core region containing hexoses, with the first two sugars, 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) and mannose, highly phosphorylated. Furthermore, the lipid A moiety has the typical structure for the genus Prevotella, and was also highly phosphorylated.


161) CSF N-Glycan Profile Reveals Sialylation Deficiency in a Patient with GM2 Gangliosidosis Presenting as Childhood Disintegrative Disorder

R.Barone, L.Sturiale, A.Fiumara, A.Palmigiano, R.O.Bua, R.Rizzo, M.Zappia, D.Garozzo

Autism Research  9,  423-428  - 2016

Protein N-glycosylation consists in the synthesis and processing of the oligosaccharide moiety (N-glycan) linked to a protein and it serves several functions for the proper central nervous system (CNS) development and function. Previous experimental and clinical studies have shown the importance of proper glycoprotein sialylation for the synaptic function and the occurrence of autism spectrum disorders (ASD) in the presence of sialylation deficiency in the CNS. Late-onset Tay Sachs disease (LOTSD) is a lysosomal disorder caused by mutations in the HEXA gene resulting in GM2-ganglioside storage in the CNS. It is characterized by progressive neurological impairment and high co-occurrence of psychiatric disturbances. We studied the N-glycome profile of the cerebrospinal fluid (CSF) in a 14 year-old patient with GM2- gangliosidosis (LOTSD). At the age of 4, the patient presented regressive autism fulfilling criteria for childhood disintegrative disorder (CDD). A CSF sample was obtained in the course of diagnostic work-up for the suspicion of an underlying neurodegenerative disorder. We found definite changes of CSF N-glycans due to a dramatic decrease of sialylated biantennary and triantennary structures and an increase of asialo-core fucosylated bisected N-glycans. No changes of total plasma N-glycans were found. Herein findings highlight possible relationships between the early onset psychiatric disturbance featuring CDD in the patient and defective protein sialylation in the CNS. In conclusion, the study first shows aberrant N-glycan structures of CSF proteins in LOTSD; unveils possible pathomechanisms of GM2-gangliosidosis; supports existing relationships between neuropsychiatric disorders and unproper protein glycosylation in the CNS.


162) The structure of the lipooligosaccharide from Xanthomonas oryzae pv. Oryzae: the causal agent of the bacterial leaf blight in rice

F.Di Lorenzo, A.Palmigiano, A.Silipo, Y.Desakic, D.Garozzo, R.Lanzetta, N.Shibuyac, A.Molinaro

Carbohydrate Research  427,  38-43  - 2016

The structure of the lipooligosaccharide (LOS) from the rice pathogen Xanthomonas oryzae pv. oryzae has been elucidated. The characterization of the core oligosaccharide structure was obtained by the employment of two chemical degradation protocols and by analysis of the products via NMR spectroscopy. The structure of the lipid A portion was achieved by MALDI mass spectrometry analysis on purified lipid A. The LOS from Xanthomonas oryzae pv. oryzae revealed to possess the same core structure of Xanthomonas campestris pv. campestris and interesting novel features on its lipid A domain. The evaluation of the biological activity of both LOS and isolated lipid A was also executed.

graphical abstract



163) A novel hybrid linear-hyperbranched poly(butylene adipate) copolymer as an epoxy resin modifier with toughening effect

F.Shiravand, L.Ascione, P.Persico, C.Carfagna, Th.Brocks, M.O.Hilário Cioffi, C.Puglisi, F.Samperi, V.Ambrogi

Polymer International  65,  308-319  - 2016

A study was carried out on the effect of a hybrid linear-hyperbranched poly(butylene adipate) copolymer on the properties of a commercial epoxy resin. First, the synthesis of the hyperbranched systems was optimized. These systems were obtained by reacting linear oligomers with 1,1,1-tris(hydroxymethyl)propane used as branching agent and varying the reaction times from 16 to 44 h. The synthesized samples were characterized through matrix-assisted laser desorption ionization time-of-flight mass spectrometry, differential scanning calorimetry and thermogravimetric analysis. Results showed that for reaction times of 30 h a highly branched system, namely 5HB30, was obtained. This system was chosen as toughening agent for a commercial high-performance epoxy resin. A kinetics analysis of epoxy/5HB30 blends indicated that the hyperbranched system had no accelerator or catalytic effect on the crosslinking reaction in the resin. Furthermore, it was demonstrated that 5HB30 acted as an excellent toughening agent, increasing significantly impact resistance up to 90% with respect to neat epoxy resin. The toughness behaviours of epoxy-based blends were explained by investigating the fracture surface after impact tests through scanning electron microscopy before and after solvent etching. It was observed that the globular-like hyperbranch-rich domains, dispersed throughout the continuous epoxy resin, were able to absorb the impact energy without affecting thermal stability.


164) Determination of polyethylene in biodegradable polymer blends and in compostable carrier bags by Py-GC/MS and TGA

P.Rizzarelli, M.Rapisarda, S.Perna, E.F.Mirabella, S.La Carta, C.Puglisi, G.Valenti

Journal of Analytical and Applied Pyrolysis  117,  72-81  - 2016

In this paper, the amount of polyethylene (PE) contained in complex biodegradable polymer blends and in carrier bags claimed to be compostable was determined by thermogravimetry analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). To validate the method, polymer blends based on polylactide (PLA), poly(butylene adipate-co-butylene terephthalate) 53/47 (PBAT), native starch (NS), and calcium carbonate, with known amount of PE ranging from 0 to 10%, were prepared by melt mixing. Py-GC/MS parameters were optimized. In the first step at 400 °C, pyrolysis products originated from thermal cracking of PLA, NS and PBAT were detected. In the second step carried out at 500 °C, triplet peaks characteristic for PE, consisting of α,ω-dienes, α-alkenes and n-alkanes, were revealed together with some signals related to PBAT. TGA under nitrogen atmosphere was used to determine the amount of PE in the blends. An overestimation of about 1.2%, constant for all the blends, was revealed. The overestimation was attributed to the partial overlapping of one of the steps of degradation of the commercial PBAT and that of PE. Additionally, the analytical approach was applied in the characterization of carrier bags claimed to be compostable, recovered directly from the market. The correct determination of the composition of these biodegradable blends is important and crucial to comply with the compostability standard EN 13432-2000. According to this standard, each significant organic constituent of the packaging material must be biodegradable. "Significant" means any constituent present in more than 1% of dry weight of that material. This implies that maximum allowed PE concentration that can be detected in a compostable blend is 1%. In two commercial carrier bags, TGA revealed a component with a degradation temperature of about 455 °C corresponding to that of PE. The relative weight loss percentages of these two carrier bags have been estimated 7.6 and 14%. Optimization of the Py-GC/MS conditions allowed identifying its chemical structure. In fact, the Py-GC/MS at 500 °C provided a pyrogram that was a fingerprint for PE with triplets corresponding to linear chains of α,ω-dienes, α-alkenes and n-alkanes with chain lengths in the range of 9-36 C atoms. Overall, the results show that the combination of TGA and Py-GC/MS can be applied with practical implications.


165) Multi-functional polyhedral oligomeric silsesquioxanefunctionalized carbon nanotubes for photo-oxidative stable Ultra-High Molecular WeightPolyethylene-based nanocomposites

N.Tz.Dintcheva, R.Arrigo, S.Carroccio, G.Curcuruto, M.Guenzi, C.Gambarotti, G.Filippone

European Polymer Journal  75,  525-537  - 2016

Nanohybrid (phPOSS-f-CNTs) based on Carbon Nanotubes (CNTs) and Phenyl Polyhedral Olygomenric Silsesquioxane (phPOSS) have been synthesized to be used as multifunctional filler for polymer nanocomposites. The success of the functionalization procedure has been demonstrated via accurate spectroscopic, spectrometric and thermo-gravimetric analyses. The results reveal that a large portion of phPOSS is covalently linked to CNTs, while a small amount of phPOSS remains physically adsorbed due to the strong interactions coming from π electron coupling between the CNTs and phenyl rings in phPOSS. Small amounts (1 wt.%) of phPOSS-f-CNTs have been dispersed in Ultra High Molecular Weight Polyethylene (UHMWPE), aiming at improving the photo-stability of the resulting nanocomposite. The rheological and thermo-mechanical behavior of UHMWPE/phPOSS-f-CNTs nanocomposite reflects two different opposite contributions, namely the reinforcement effect of CNTs and the plasticizing action of phPOSS molecules. Concerning the photo-oxidative behavior, phPOSS-f-CNTs show a remarkable protective ability, which is absolutely much higher than those exerted by CNTs and phPOSS molecules when added one by one. Such unexpected results could be explained considering (i) a synergic effect between phPOSS and CNTs, (ii) the possibility of phPOSS to act at the polymer-nanoparticles interface, which is a critical region for the degradation processes, and (iii) the formation of a phPOSS-rich layer that may hinder the oxygen diffusion within the polymeric matrix.

graphical abstract



166) N-Linked Glycans of Chloroviruses Sharing a Core Architecture without Precedent

C.De Castro, I.Speciale, G.Duncan, D.D.Dunigan, I.Agarkova, R.Lanzetta, L.Sturiale, A.Palmigiano, D.Garozzo, A.Molinaro, M.Tonetti, J.L.Van Etten

Angewandte Chemie International Edition  55,  654-658  - 2016

DOI: https://doi.org/10.1002/ange.201509150
N-glycosylation is a fundamental modification of proteins and exists in the three domains of life and in some viruses, including the chloroviruses, for which a new type of core N-glycan is herein described. This N-glycan core structure, common to all chloroviruses, is a pentasaccharide with a β-glucose linked to an asparagine residue which is not located in the typical sequon N-X-T/S. The glucose is linked to a terminal xylose unit and a hyperbranched fucose, which is in turn substituted with a terminal galactose and a second xylose residue. The third position of the fucose unit is always linked to a rhamnose, which is a semiconserved element because its absolute configuration is virus-dependent. Additional decorations occur on this core N-glycan and represent a molecular signature for each chlorovirus.

graphical abstract



167) CSF N-glycoproteomics for early diagnosis in Alzheimer’s disease

A.Palmigiano, R.Barone, L.Sturiale, C.Sanfilippo, R.O.Bua, D.Romeo, A.Messina, M.L.Capuana, T.Maci, F.Le Pira, M.Zappia, D.Garozzo

Journal of Proteomics   131,  29-37  - 2016

DOI: https://doi.org/10.1016/j.jprot.2015.10.006
This work aims at exploring the human CSF (Cerebrospinal fluid) N-glycome by MALDI MS techniques, in order to assess specific glycosylation pattern(s) in patients with Alzheimer’s disease (n:24) and in subjects with mild cognitive impairment (MCI) (n:11), these last as potential AD patients at a pre-dementia stage. For comparison, 21 healthy controls were studied. We identified a group of AD and MCI subjects (about 40-50% of the studied sample) showing significant alteration of CSF N-glycome profiling, consisting of a decrease in the overall sialylation degree and an increase in species bearing bisecting GlcNAc. Noteworthy, all the MCI patients that converted to AD within the clinical follow-up, had an abnormal CSF glycosylation profile. Based on the studied cohort, CSF glycosylation changes may occur before an AD clinical onset. Previous studies specifically focused on the key role of glycosyltransferase GnT-III on AD-pathogenesis, addressing the patho-mechanism to specific sugar modification of BACE-1 glycoprotein with bisecting GlcNAc. Our patients addressed protein N-glycosylation changes at an early phase of the whole biomolecular misregulation on AD, pointing to CSF N-glycome analyses as promising tool to enhance early detection of AD and also suggesting alternative therapeutics target molecules, such as specific glyco-enzymes.

graphical abstract



168) Grafting of polymer chains on the surface of carbon nanotubes via nitroxide radical coupling reaction

C.Yang, M.Guenzi, F.Cicogna, C.Gambarotti, G.Filippone, C.Pinzino, E.Passaglia, N.Tz.Dintcheva, S.Carroccio, S.Coiai

Polymer International   65,  48-56  - 2016

Poly(butylene succinate) (PBS) was grafted on the surface of TEMPO (2,2,6,6-tetramethylpiperidinyl‐1‐oxyl) modified multi‐walled carbon nanotubes (MWCNTs) via nitroxide radical coupling reaction. TEMPO functionalized MWCNTs (MWCNTs‐g‐TEMPO) were synthesized using the Cu(I)‐catalyzed azide/alkyne‐click chemistry approach and the covalent bond of the nitroxide moieties onto the MWCNTs was confirmed via electron paramagnetic resonance (EPR) spectroscopy. The PBS grafting on the sidewalls of MWCNTs was carried out in solution via peroxide‐induced formation of macroradicals and it was confirmed by EPR and ATR‐FTIR analysis. Preliminary rheological and calorimetric analyses revealed that the grafting improves both the quality of stress transfer across the polymer‐nanotube interface and the degree of dispersion of the filler, which also exhibited a moderate nucleating action on the PBS. Overall, our results demonstrate that the nitroxide radical coupling is an efficient and feasible "grafting to" method to covalently bond polymer chains on MWCNTs with possible advantages in the final properties of polymer nanocomposites.


169) Analytical approaches to the diagnosis and treatment of aging and aging-related disease: redox status and proteomics

V.Calabrese, S.Dattilo, A.Petralia, R.Parenti, M.Pennisi, G.Koverech, A.Graziano, I.Monte, L.Maiolino, T.Ferreri, E.J.Calabrese

Free Radical Research  49(5),  511-524  - 2015

Basal levels of oxidants are indispensible for redox signaling to produce adaptive cellular responses such as vitagenes linked to cell survival; however, at higher levels, they are detrimental to cells, contributing to aging and to the pathogenesis of numerous age-related diseases. Aging is a complex systemic process and the major gap in aging research reminds the insufficient knowledge about pathways shifting from normal "healthy" aging to disease-associated pathological aging. The major complication of normal "healthy" aging is in fact the increasing risk of age-related diseases such as cardiovascular diseases, diabetes mellitus, and neurodegenerative pathologies that can adversely affect the quality of life in general, with enhanced incidences of comorbidities and mortality. In this context, global "omics" approaches may help to dissect and fully study the cellular and molecular mechanisms of aging and age-associated processes. The proteome, being more close to the phenotype than the transcriptome and more stable than the metabolome, represents the most promising "omics" field in aging research. In the present study, we exploit recent advances in the redox biology of aging and discuss the potential of proteomics approaches as innovative tools for monitoring at the proteome level the extent of protein oxidative insult and related modifications with the identification of targeted proteins.


170) Heat shock proteins and hormesis in the diagnosis and treatment of neurodegenerative diseases

S.Dattilo, C.Mancuso, G.Koverech, P.Di Mauro, M.L.Ontario, C.C.Petralia, A.Petralia, L.Maiolino, A.Serra, E.J.Calabrese, V.Calabrese

Immunity & Ageing   - 2015

Modulation of endogenous cellular defense mechanisms via the vitagene system represents an innovative approach to therapeutic intervention in diseases causing chronic tissue damage, such as in neurodegeneration. The possibility of high-throughoutput screening using proteomic techniques, particularly redox proteomics, provide more comprehensive overview of the interaction of proteins, as well as the interplay among processes involved in neuroprotection. Here by introducing the hormetic dose response concept, the mechanistic foundations and applications to the field of neuroprotection, we discuss the emerging role of heat shock protein as prominent member of vitagene network in neuroprotection and redox proteomics as a tool for investigating redox modulation of stress responsive vitagenes. Hormetic mechanisms are reviewed as possibility of targeted therapeutic manipulation in a cell-, tissue- and/or pathway-specific manner at appropriate points in the neurodegenerative disease process.


171) Environmental benefits of using ground tyre rubber in new pneumatic formulations: A life cycle assessment approach

A.D.La Rosa, G.Recca, D.Carbone, S.Battiato, A.Latteri, G.Cozzo, G.Cicala

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications  229(4),  309-317  - 2015

Life cycle assessment methodology was applied as a tool to evaluate the real environmental benefit of using recycled waste tyres in mixture with virgin rubber. Styrene-isoprene-styrene rubber was mixed with different amounts of ground tyre rubber and vulcanised. Thermomechanical analysis (i.e. differential scanning calorimetry and thermogravimetric analysis) and dynamic mechanical thermal analysis were carried out in order to evaluate the compatibility of the rubber mixture and the chemical-physical properties of the vulcanised products. Experimental analysis results show that the addition of ground tyre rubber up to 50 phr does not sensibly affect the vulcanisation reaction, the wet skid resistance and the rolling resistance. Life cycle assessment results show that the main environmental impacts of the ground tyre rubber are associated to the use of virgin rubber (47.1%) and carbon black (34.3%) while the tyre grinding process contributes only for 4%. Because ground tyre rubber contains carbon black in its formulation, the substitution of virgin rubber with ground tyre rubber has double environmental benefits: to reduce the need of both amounts of virgin rubber and fresh carbon black in the new formulation


172) Some Comments on a Recent Article Dealing with Three Aliphatic-Aromatic Polyesters and Their Spectral Identification

M.S.Montaudo

International Journal of Polymer Analysis and Characterization  20(6),  557-564  - 2015

This work discusses the results appearing in Wu et al.’s (2014) article dealing with three aliphatic-aromatic polyesters based on terephthalic acid and their spectral identification. Using an instrument equipped with a switch that allows ions with masses below 5 kDa to be discarded (ion deflector), the authors report the MALDI spectrum of a commercial poly(ethylene terephthalate) with signals up to 80 kDa. I plot the spectral intensities and fit them with a Gaussian curve. The result is carefully examined. Thereafter, attention is moved to the MALDI spectra obtained when the ion deflector is turned off. A computation that gives the number-average and the weight-average molar mass (Mn and Mw) was performed, but the result was Mn = 1362 g/mol and Mw = 1416 g/mol. These values are much too low and they cannot be used. In order to explain this failure, I modified a model developed for poly(pentylene adipate). This hypothesis is discarded and the correct explanation is found. I also discuss other types of instrumentation, for instance, Py-GC/MS combined with library-search and also NMR spectroscopy, with specific reference to the chemical shifts of the -CH2- protons in aliphatic-aromatic polyesters.


173) Matrix-assisted laser desorption/ionization time-of-flight vs. fast-atom bombardment and electrospray ionization mass spectrometry in the structural characterization of bacterial poly(3-hydroxyalkanoates)

G.Impallomeni, A.Ballistreri, G.M.Carnemolla, D.Franco, S.P.P.Guglielmino

Rapid Communications in Mass Spectrometry  29(9),  811-820  - 2015

Rationale

Bacterial poly(3-hydroxyalkanoates) (PHAs) are an emergent class of plastic materials available from renewable resources. Their properties are strictly correlated with the comonomeric composition and sequence, which may be determined by various mass spectrometry approaches. In this paper we compare fast-atom bombardment (FAB) and electrospray ionization (ESI) to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of partially pyrolyzed samples.

Methods

We determined the compositions and sequences of the medium-chain-length PHAs (mcl-PHAs) prepared by bacterial fermentation of Pseudomonas aeruginosa ATCC 27853 cultured in media containing fatty acids with 8, 12, 14, 18, and 20 carbon atoms as carbon sources by means of MALDI-TOFMS of pyrolyzates, and compared the results with those obtained by FAB- and ESI-MS in previous studies. MALDI matrices used were 9-aminoacridine (9-AA) and indoleacrylic acid (IAA).

Results

MALDI-TOFMS was carried out in negative ion mode when using 9-AA as a matrix, giving a semi-quantitative estimation of the 3-hydroxyacids constituting the PHAs, and in positive mode when using IAA, allowing us, through statistical analysis of the relative intensity of the oligomers generated by pyrolysis, to establish that the polymers obtained are true random copolyesters and not a mixture of homopolymers or copolymers.

Conclusions

MALDI-TOFMS in 9-AA and IAA of partial pyrolyzates of mcl-PHAs represents a powerful method for the structural analysis of these materials. In comparison with FAB and ESI, MALDI provided an extended mass range with better sensitivity at higher mass and a faster method of analysis.


174) New amphiphilic derivatives of poly(ethylene glycol) (PEG) as surface modifiers of colloidal drug carriers. III. Lipoamino acid conjugates with carboxy- and amino-PEG5000 polymers

R.Pignatello, G.Impallomeni, V.Pistarà, S.Cupria, A.C.E.Graziano, V.Cardile, A.Ballistreri

Materials Science and Engineering: C  46,  470-481  - 2015

Within a research directed to developing new polymeric materials, suitable for decorating the surface of colloidal drug carriers, PEG5000 polymers containing a free carboxyl or amine group at one end were conjugated to an α-lipoamino moiety (LAA). The conjugates were characterized by FT-IR, 1H-NMR, and MALDI-TOF mass spectrometry. They showed the same profile of solubility as the parent PEGs in water and in some polar and apolar solvents of pharmaceutical use. Representative terms showed to be well tolerated when incubated with Caco-2 or L929 cell cultures. Dedicated differential scanning calorimetry (DSC) studies were performed to prove the interaction of increasing molar fractions of the PEG5000-LAA conjugates with dipalmitoylphosphatidylcholine (DPPC) bilayers, to gain information about their possible incorporation in drug nanocarriers. While the parent PEGs affected only the superficial structure of bilayers, the amphiphilic PEG-LAA conjugates induced a perturbing effect on the thermotropic behavior of DPPC liposomes, according to the structure of the linked LAA residue. A molar concentration of these PEG-LAA between 5 and 10% was individuated as the most suitable to produce stable vesicles.

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175) Characterization of amphiphilic block-copolymers constituted of a low band gap rigid segment (PCPDTBT) and P4VP based coil block synthesized by two different strategies

S.Zappia, R.Mendichi, S.Battiato, G.Scavia, R.Mastria, F.Samperi, S.Destri

Polymer  80,  245-258  - 2015

Two homologous series of rod-coil block-copolymers, composed by a low band gap rod moiety (poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b:3.4-b’]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)], PCPDTBT) and a flexible poly(4-vinylpyridine) based polar block, were synthesized by two different approaches. Step Growth-like procedure provided copolymers with longer coil, whilst copolymers with longer rod arise from Chain Growth-like process. Both the series were deeply investigated with different analytical techniques (1H NMR, SEC-DV, and MALDI-TOF MS) in order to prove the coupling process and elucidate the composition of the obtained materials. Chemical composition was evaluated by 1H NMR analysis. DSC heating traces of rod-coil copolymers synthesized by Step Growth-like route present two well resolved glass transition temperatures corresponding to the rod and coil blocks. The low band-gap rod-coil block copolymers especially these with short coil can find application in hybrid solar cells.

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176) Structural Relationship of the Lipid A Acyl Groups to Activation of Murine Toll-Like Receptor 4 by Lipopolysaccharides from Pathogenic Strains of Burkholderia mallei, Acinetobacter baumannii, and Pseudomonas aeruginosa

K.V.Korneev, N.P.Arbatsky, A.Molinaro, A.Palmigiano, R.Z.Shaikhutdinova, M.M.Shneider, G.B.Pier, A.N.Kondakova, E.N.Sviriaeva, L.Sturiale, D.Garozzo, A.A.Kruglov, S.A.Nedospasov, M.S.Drutskaya, Y.A.Knirel, D.V.Kuprash

Frontiers in Immunology   6  - 2015

Toll-like receptor 4 (TLR4) is required for activation of innate immunity upon recognition of lipopolysaccharide (LPS) of Gram-negative bacteria. The ability of TLR4 to respond to a particular LPS species is important since insufficient activation may not prevent bacterial growth while excessive immune reaction may lead to immunopathology associated with sepsis. Here, we investigated the biological activity of LPS from Burkholderia mallei that causes glanders, and from the two well-known opportunistic pathogens Acinetobacter baumannii and Pseudomonas aeruginosa (causative agents of nosocomial infections). For each bacterial strain, R-form LPS preparations were purified by hydrophobic chromatography and the chemical structure of lipid A, an LPS structural component, was elucidated by HR-MALDI-TOF mass spectrometry. The biological activity of LPS samples was evaluated by their ability to induce production of proinflammatory cytokines, such as IL-6 and TNF, by bone marrow-derived macrophages. Our results demonstrate direct correlation between the biological activity of LPS from these pathogenic bacteria and the extent of their lipid A acylation.


177) Aliphatic poly(ester amide)s from sebacic acid and aminoalcohols of different chain length: Synthesis, characterization and soil burial degradation

P.Rizzarelli, M.Cirica, G.Pastorelli, C.Puglisi, G.Valenti

Polymer Degradation and Stability   121,  90-99  - 2015

High molar mass aliphatic poly(ester amide)s were prepared from sebacic acid and aminoalcohols of different chain length by melt polycondensation and chain extension reactions. Low molecular weight aliphatic poly(ester amide)s were synthesized by melt polycondensation starting from sebacic acid and linear aminoalcohols of different chain lengths, ranging from 2 to 6 methylene groups. Then, chain extension reaction was carried out by using 1,6-hexamethylene diisocyanate (HMDI). The poly(ester amide)s obtained were characterized by viscometry, DSC, MALDI mass spectrometry, and NMR. The poly(ester amide)s with a reduced viscosity ranging from 0.5 to 1.5 dL g-1 showed a good film-ability. The degradability in soil of poly(ester amide) film samples was investigated. The weight loss of commercial poly(3-hydroxy butyrate) (PHB), poly(3-hydroxy butyrate-co-3-hydroxy valerate) 76/24 (P(HB-co-HV) 76/24), poly(caprolactone) (PCL), and two poly(butylene succinate) based samples (Bionolle), was also studied under controlled soil burial conditions. The rates of soil burial degradation of synthetic poly(ester amide)s and commercial biodegradable polyesters having different structures were compared. Interestingly, the poly(ester amide)s synthesized show higher weight loss values than polyester films after 5 and 10 days of soil burial degradation test.


178) Bithiophene-based polybenzofulvene derivatives with high stacking and hole mobility

A.Cappelli, V.Razzano, M.Paolino, G.Grisci, G.Giuliani, A.Donati, R.Mendichi, F.Samperi, S.Battiato, A.C.Boccia, A.Mura, G.Bongiovanni, W.Mróz, C.Botta

Polymer Chemistry  42,  7355-7486  - 2015

Four new benzofulvene derivatives bearing bithiophene chromophores at two different key positions of the phenylindene scaffold were prepared in order to evaluate the role of different chromophores in the optoelectronic features of polybenzofulvene derivatives. The results of the photophysical studies showed that the optical properties of the newly-synthesized bithiophene-functionalized polymers were affected by both the polymer enchainment and the substitution topology of the monomeric units. On the other hand, the hole-mobility appeared to be affected to a lesser extent, but the best performances were obtained in poly-6-HBT-BF3k showing the strongest bithiophene side chain packing. This work demonstrates that the optoelectronic properties of polybenzofulvene derivatives can be optimized by a targeted chemical design such as side chain engineering.

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179) Multi-functional hindered amine light stabilizers-functionalized carbon nanotubes for advanced ultra-high molecular weight Polyethylene-based nanocomposites

N.Tz.Dintcheva, R.Arrigo, E.Morici, C.Gambarotti, S.Carroccio, F.Cicogna, G.Filippone

Composites Part B: Engineering   82,  196-204  - 2015

Hindered Amine Light Stabilizer (HAS) molecules have been covalently linked on the outer surface of multi-walled carbon nanotubes (CNTs), and the so-obtained multi-functional fillers (HAS-f-CNTs) have been compounded with Ultra High Molecular Weight Polyethylene (UHMWPE) to get composite films. The success of the grafting reaction of the HAS molecules has been confirmed through spectroscopic and thermo-gravimetric analyses. Morphological analyses reveal a segregated microstructure, in which CNT-rich channels surround the polymer domains. This morphology results in improved mechanical properties and appreciable electrical conductive features. More importantly, the addition of only 1 wt.% of HAS-f-CNTs brings about a significant improvement of the photo-oxidation resistance, which neither HAS nor CNTs can provide if used separately. The origin of this synergic effect is discussed. Overall, our results demonstrate the possibility of using properly functionalized CNTs as multi-functional fillers to get high-performance polymer composites.


180) Reactive melt mixing of PC/PEN blend. Structural characterization of reaction products

F.Samperi, S.Battiato, G.Recca, C.Puglisi, R.Mendichi

Polymer  74,  108-123  - 2015

Chemical reactions occurring during reactive melt mixing of equimolar blend of poly(bisphenol-A carbonate) and poly(ethylene 2,6-naphthalate) at 280 °C in presence of a catalyst, were studied. Beside expected direct "inner-inner" ester-carbonate and outer-inner exchange reactions, consecutive reactions that lead to the elimination of CO2 and ethylene carbonate from backbone, were also detected. The composition and the architecture of the formed copolymers change as the mixing time increases. Initial PC-PEN block copolymers formed at lower mixing time (2 min) evolve towards the formation of naphthalate based random copoly(ester-ether)s at reaction time higher than 45 min, owing to total elimination of carbonate units. Determination of composition and microstructure of copolymers formed was attempted by (1H and 13C)-NMR analyses applying appropriate chemical microstructural model. Dyads and triads sequences determined here give detailed information on the change in the molar fractions of the sequences with increasing the reaction time. DSC analysis shows that block copolymer formed at 2 min mixing present two glass transition (Tg) temperatures close to those of initial homopolymers, whereas the other ones show a single Tg that changes as a function of their dyads molar compositions. Thermogravimetric analysis show that the more thermally stable copolymers are random copoly(ester-ether)s formed at higher reaction time.

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181) Time-resolved rheology as a tool to monitor the progress of polymer degradation in the melt state - Part II: Thermal and thermo-oxidative degradation of polyamide 11/organo-clay nanocomposites

G.Filippone, S.Carroccio, G.Curcuruto, E.Passaglia, C.Gambarotti, N.Tz.Dintcheva

Polymer  73,  102-110  - 2015

Thermal and thermo-oxidative degradation of nanocomposites based on polyamide 11 (PA11) and organo-modified clay (Cloisite® 30B) are studied in the melt state (T = 215 °C) via time-resolved mechanical spectroscopy (TRMS). The goal is assessing the potentiality of rheological analysis for studying polymer degradation in complex systems such as polymer nanocomposites, whose rheological response stems from the combination of the contributions of polymer and nanoparticles. We prove that a thorough analysis grounded on TRMS allows to isolate the effect of degradation of the polymer matrix, whose progress can be hence profitably monitored. Essentially the same degradation mechanisms as in neat PA11 are identified for the nanocomposite, but the kinetics of the thermo-oxidation processes are much faster in the presence of organo-clay. In particular, rheology promptly identifies cross-linking reactions since the early stage of the treatment in air. Matrix-assisted laser desorption/ionization and oxidative induction time measurements corroborate the conclusions drawn on the basis of rheological analyses, shedding light on the chemical aspects of PA11 degradation. Overall, rheological analysis confirms to be a valuable tool for monitoring polymer degradation even in case of inherently complex systems such as nanocomposites. In this case, however, the analysis can be difficult if the dynamics of the nanoparticles prevail over those of the polymer matrix, which is the case of nanocomposites at high filler contents.

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182) Insect Gut Symbiont Susceptibility to Host Antimicrobial Peptides Caused by Alteration of the Bacterial Cell Envelope

J.K.Kim, D.W.Son, C.Kim, J.H.Cho, R.Marchetti, A.Silipo, L.Sturiale, H.Y.Park, Y.R.Huh, H.Nakayama‖, T.Fukatsu, A.Molinaro, B.L.Lee

Journal Of Biological Chemistry  290 (34),  21042-21053  - 2015

The molecular characterization of symbionts is pivotal for understanding the cross-talk between symbionts and hosts. In addition to valuable knowledge obtained from symbiont genomic studies, the biochemical characterization of symbionts is important to fully understand symbiotic interactions. The bean bug (Riptortus pedestris) has been recognized as a useful experimental insect gut symbiosis model system because of its cultivatable Burkholderia symbionts. This system is greatly advantageous because it allows the acquisition of a large quantity of homogeneous symbionts from the host midgut. Using these naïve gut symbionts, it is possible to directly compare in vivo symbiotic cells with in vitro cultured cells using biochemical approaches. With the goal of understanding molecular changes that occur in Burkholderia cells as they adapt to the Riptortus gut environment, we first elucidated that symbiotic Burkholderia cells are highly susceptible to purified Riptortus antimicrobial peptides. In search of the mechanisms of the increased immunosusceptibility of symbionts, we found striking differences in cell envelope structures between cultured and symbiotic Burkholderia cells. The bacterial lipopolysaccharide O antigen was absent from symbiotic cells examined by gel electrophoretic and mass spectrometric analyses, and their membranes were more sensitive to detergent lysis. These changes in the cell envelope were responsible for the increased susceptibility of the Burkholderia symbionts to host innate immunity. Our results suggest that the symbiotic interactions between the Riptortus host and Burkholderia gut symbionts induce bacterial cell envelope changes to achieve successful gut symbiosis.


183) Time-resolved rheology as a tool to monitor the progress of polymer degradation in the melt state - Part I: Thermal and thermo-oxidative degradation of polyamide 11

G.Filippone, S.Carroccio, R. Mendichi, L.Gioiella, N.Tz.Dintcheva, C.Gambarotti

Polymer  72,  134-141  - 2015

Thermal and thermo-oxidative degradation of polyamide 11 (PA11) in the melt state (T = 215 °C) are studied by resorting to time-resolved mechanical spectroscopy. Such an approach allows to elude the changes in the rheological properties occurring while testing, thus enabling the rigorous study of polymer degradation in the melt state. Different concurrent degradation reactions in oxidative (air) and non-oxidative (N2) environment are promptly guessed by studying the time evolutions of rheological functions. In particular, changes in the zero-frequency complex viscosity reflects changes in the average molecular weight, while the appearance of a yield stress in the complex viscosity curve is identified as the rheological fingerprint of cross-linking reactions. Size exclusion chromatography corroborates the hypotheses based on rheological analyses, and matrix assisted laser desorption/ionization mass spectrometry sheds light on the chemical aspects of degradation. Specifically, post-condensation (in N2), chain scission, hydrolysis and cross-linking reactions (in air) are identified as the dominant degradation mechanisms of PA11 in the melt state. Overall, our study demonstrates that rheology is a valuable tool to detect and discriminate among different degradation mechanisms in polymer melts. In particular, rheology promptly identifies cross-linking reactions, which can be difficult to be detected through common analytical techniques that envisage the solubilization of the polymer sample.

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184) Advanced ultra-high molecular weight polyethylene/ antioxidantfunctionalized carbon nanotubes nanocomposites with improved thermo-oxidative resistance

N.T.Dintcheva, R.Arrigo, C.Gambarotti, S.Carroccio, S.Coiai, G.Filippone

Journal of Applied Polymer Science  132(33),  42420  - 2015

Multiwalled carbon nanotubes (CNTs) functionalized with hindered phenol moieties are dispersed in ultra-high molecular weight polyethylene (UHMWPE), and the stabilizing action of the antioxidant (AO) functionalized CNTs (AO-f-CNTs) is studied through a combination of rheological and spectroscopic (FT-IR) analyses. The effectiveness of two alternative compounding methods, namely hot compaction (HC) and melt mixing (MM), is compared. The combination of high temperature and mechanical stress experienced during MM brings about noticeable degradation phenomena of the matrix already in the course of the compounding step. Differently, the milder conditions of the HC process preserve the stability of the polymer, making this method preferable when dealing with highly viscous matrices. In addition, HC guarantees a better CNT dispersion, allowing for the maximization of the stabilizing action of the AO grafted on the nanotubes. As a result, the HC samples exhibit improved thermo-oxidative resistance despite the very low amount of AO grafted onto the CNTs. Besides demonstrating the effectiveness of our AO-f-CNTs as stabilizers for polymer matrices, our results prove that CNTs can serve as a support on which grafting specific functional molecules to be dispersed in a host polymer matrix.


185) TEAR FLUID N-GLYCAN PROFILING TO INVESTIGATE BIOMARKERS IN VERNAL AND ATOPIC KERATOCONJUNCTIVITIS

A.Leonardi, C.Tosto, A.Messina, A.Palmigiano, R.O.Bua, D.Romeo, L.Sturiale, D.Garozzo

Investigative Ophthalmology & Visual Science  56(7),  5875  - 2015

Proteomics and glycogene-chips studies revealed that several tear proteins are glycosylated. Glycoproteins play a role in different function of the ocular surface including protection against pathogens, immunoregulation and prevention of desiccation. In the present study, we analyze the N-linked glycome of tear fluid from patients affected by vernal (VKC) and atopic keratoconjunctivitis (AKC) in order to identify potential biomarkers for these diseases. To date, no specific laboratory test are suitable for VKC and AKC diagnosis and monitoring. Tear samples from 23 VKC patients, 7 AKC patients and 11 control subjects were diluted 1/10 in a denaturant solution, reduced, alkylated and treated with N-glycosidase F (PNGase F), an enzyme which specifically deglycosylates N-glycoproteins. Released N-glycans were purified, chemically derivate by permethylation and analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS and MALDI TOF/TOF MS/MS). The eligibility of mass spectrometry for the study of glycosylation is due to its high sensibility and ability to analyze complex mixtures of glycans from biological samples. Our approach allowed to identify more than 150 complex N-glycans, including biantennary, triantennary, tetraantennary and bisecting species. Highly fucosylated structures were also found. Data analysis showed changes in terms of relative intensities for some structures. In VKC, the most significant peaks were related to mass to charge ratios 1906.7 and 2592.3, corresponding to a bisecting and to a N-glycan structure bearing two Lewis-X epitope, respectively.In AKC the most intense peak is found at m/z 2792.4, and corresponds to the well-known biantennary, disialylated N-glycan. Each structure reveals significant differences between healthy and pathological conditions, with major variations involving bisecting and hyperfucosylated glycoforms. Structures were confirmed in detail by MS/MS analysis. MALDI-TOF-MS is a valuable technique for biomarker detection and characterization of defective glycan structures. Identified peaks could be used as potential biomarkers for VKC and AKC. Further structural characterization of the disease-associated N-glycans may confirm these preliminary results and allow to discover additional biomarkers.


186) Acetylcholinesterase-induced fluorescence turn-off of an oligothiophene-grafted quartz surface sensitive to myristoylcholine

G.Grisci, W.Mróz, U.Giovanella, K.Pagano, W. Porzio, L.Ragona, F.Samperi, S.Tomaselli, F.Galeotti, S.Destria

Journal of Materials Chemistry B  3,  4892-4903  - 2015

Conjugated polyelectrolytes (CPEs) have recently emerged as label-free materials for biosensing due to their intrinsic ability to transduce an amplified optical signal in response to interactions with different analytes. Herein, the conformational change of an anionic oligothiophene is exploited to generate a unique fluorescent response upon interaction with myristoylcholine (MyrCh). The variations observed in spectroscopic signals are explained in terms of a synergistic combination of hydrophobic and electrostatic forces involving the oligothiophene chains and MyrCh molecules, inducing the disassembling of oligothiophene chains. The enzyme acetylcholinesterase (AChE) is able to reverse this effect by catalyzing the hydrolysis of MyrCh; hence, its enzymatic activity can be monitored through the variation of fluorescence emission of the system. The oligothiophene sensing probe retains its conformational sensitivity with regard to the AChE-mediated cleavage of MyrCh upon immobilization onto a quartz substrate, which is accomplished by a "grafting onto" approach based on click chemistry. These results are encouraging for the further development of such a label-free system towards the fabrication of sensing devices that would incorporate CPEs and would be potentially useful for the specific detection of a wide range of bioanalytes.

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187) Determination of the structure of the O-antigen and the lipid A from the entomopathogenic bacterium Pseudomonas entomophila lipopolysaccharide along with its immunological properties

I.Speciale, I.Paciello, L.Lembo Fazio, L.Sturiale, A.Palmigiano, R.Lanzetta, M.Parrilli, D.Garozzo, B.Lemaitre, M.L.Bernardini, A.Molinaro, C.De Castro

Carbohydrate Research  412,  20-27  - 2015

DOI: https://doi.org/10.1016/j.carres.2015.04.017
The structure and the immunology of the lipopolysaccharide (LPS) of Pseudomonas entomophila, an entomopathogenic bacterium isolated from the fruit fly Drosophila melanogaster, was characterized. The O-antigen portion was established and resulted to be built up of a repetitive unit constituted by four monosaccharide residues, all L configured, all deoxy at C-6 and with an acetamido function at C-2: →3)-α-L-FucNAc-(1→4)-α-L-FucNAc-(1→3)-α-L-FucNAc-(1→3)-β-L-QuiNAc-(1→ The structural analysis of lipid A, showed a mixture of different species. The diphosphorylated glucosamine backbone carries six fatty acids consistent with the composition C10:0 3(OH), C12:0 2(OH) and C12:0 3(OH), whereas other species differs by the number of phosphates and/or of fatty acids. The immunology experiments demonstrated that the LPS structure of P. entomophila displayed a low ability to engage the TLR4-mediated signaling correlated to a significant antagonistic activity toward hexaacylated LPS structures.

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188) Thermo-oxidative resistant nanocomposites containing novel hybrid-nanoparticles based on natural polyphenol and carbon nanotubes

R.Arrigo, N.Tz.Dintcheva, M.Guenzi, C.Gambarotti, G.Filippone, S.Coiai, S.Carroccio

Polymer Degradation and Stability  115,  129-137  - 2015

Quercetin (Q), a natural antioxidant molecule, is physically immobilized onto multi-walled carbon nanotubes (CNTs) bearing covalently-linked long-chain alkyl functional groups, and the so obtained hybrid-nanoparticles are used to prepare Ultra High Molecular Weight PolyEthylene-based nanocomposite films with enhanced thermo-oxidation resistance. The effective immobilization of the Q molecules is confirmed by spectroscopic (micro-Raman, ATR-FTIR, and FTIR) and thermo-gravimetric analyses, and the influence of the nanoparticles on the rheological behaviour and thermo-oxidative stability of the nanocomposites are investigated. Rheological analyses (linear viscoelasticity and stress relaxation tests) and morphological observations reveal that the Q-functionalized CNTs disperse better than bare CNTs in the host matrix. Quercetin confirms to be an excellent anti-oxidant for polyethylene, but the study of the thermo-oxidation behaviour shows that a remarkable stabilizing action only emerges when Q is physically immobilized on the CNTs. In particular, a ten-fold increase of the onset of degradation phenomena in thermo-oxidative environment was found. Such an excellent result is due to a synergic effect stemming from the physical interaction between Q and CNTs, which cannot provide a similar stabilizing action if used separately. In particular, we argue that the process of physical immobilization of the Q molecules causes the formation of structural defects onto outer CNTs surfaces, thus remarkably improving the CNTs radical scavenging activity and probably promoting Q regeneration. In addition, CNTs seem acting as efficient nano-carriers for the quercetin molecules, improving the dispersion of the latter in the host matrix in spite of their poor solubility.


189) A nationwide survey of PMM2-CDG in Italy: high frequency of a mild neurological variant associated with the L32R mutation

R.Barone, M.Carrozzi, R.Parini, R.Battini, D.Martinelli, M.Elia, M.Spada, F.Lilliu, G.Ciana, A.Burlina, V.Leuzzi, M.Leoni, L.Sturiale, G. Matthijs, J.Jaeken, M.Di Rocco, D.Garozzo, A.Fiumara

Journal of Neurology  ,  154-164  - 2015

PMM2-CDG (PMM2 gene mutations) is the most common congenital disorder of N-glycosylation. We conducted a nationwide survey to characterize the frequency, clinical features, glycosylation and genetic correlates in Italian patients with PMM2-CDG. Clinical information was obtained through a questionnaire filled in by the referral physicians including demographics, neurological and systemic features, neuroimaging data and genotype. Glycosylation analyses of serum transferrin were complemented by MALDI-Mass Spectrometry (MALDI-MS). Between 1996 and 2012, data on 37 Italian patients with PMM2-CDG were collected. All the patients with a severe phenotype were unable to walk unaided, 84 % had severe intellectual disability and 81 % microcephaly. Conversely, among 17 mildly affected patients 82 % had independent ambulation, 64 % had borderline to mild intellectual disability and 35 % microcephaly. Epilepsy and stroke-like events did not occur among patients with the mild phenotype. The rate and extent of systemic involvement were more pronounced in severely affected patients. The L32R misfolding mutation of the PMM2 gene occurred in 70 % of the patients with the mild phenotype and was associated with a less severe underglycosylation of serum Tf at MALDI-MS analyses. Despite their different disease severity, all patients had progressive (olivo)ponto-cerebellar atrophy that was the hallmark clinical feature for the diagnosis. A mild neurological phenotype of PMM2-CDG marked by preserved ambulatory ability and autonomy and associated with L32R mutation is particularly frequent in Italy. PMM2-CDG should be considered in patients with even mild developmental disability and/or unexplained progressive cerebellar atrophy.


190) Persistent cystic fibrosis isolate Pseudomonas aeruginosa strain RP73 exhibits an under-acylated LPS structure responsible of its low inflammatory activity

F.Di Lorenzo, A.Silipo, I.Bianconi, N.I.Loré, A. Scamporrino, L.Sturiale, D.Garozzo, R.Lanzetta, M.Parrilli, A.Bragonzi, A.Molinaro

Molecular Immunology  63,  166-175  - 2015

Pseudomonas aeruginosa, the major pathogen involved in lethal infections in cystic fibrosis (CF) population, is able to cause permanent chronic infections that can persist over the years. This ability to chronic colonize CF airways is related to a series of adaptive bacterial changes involving the immunostimulant lipopolysaccharide (LPS) molecule. The structure of LPSs isolated from several P. aeruginosa strains showed conserved features that can undergo chemical changes during the establishment of the chronic infection. In the present paper, we report the elucidation of the structure and the biological activity of the R-LPS (lipooligosaccharide, LOS) isolated from the persistent CF isolate P. aeruginosa strain RP73, in order to give further insights in the adaptation mechanism of the pathogen in the CF environment. The complete structural analysis of P. aeruginosa RP73 LOS was achieved by chemical analyses, NMR spectroscopy and MALDI MS spectrometry, while the assessment of the biological activity was attained testing the in vivo pro-inflammatory capacity of the isolated LOS molecule. While a typical CF LPS is able to trigger a high immune response and production of pro-inflammatory molecules, this P. aeruginosa RP73 LOS showed to possess a low pro-inflammatory capacity. This was possible due to a singular chemical structure possessing an under-acylated lipid A very similar to the LPS of P. aeruginosa found in chronic lung diseases such as bronchiectstasis.


191) Bio-based versus traditional polymer composites. A life cycle assessment perspective

A.D.La Rosa, G.Recca, J.Summerscales, A.Latteri, G.Cozzo, G.Cicala

Journal of Cleaner Production  74(1),  135-144  - 2014

A comparative LCA between an eco-sandwich made of bio-based epoxy resin (SuperSap 100/1000) and natural fibers against a traditional sandwich made of epoxy/glass-fibers was carried out. The main purpose and contribution of this study is the exploration of the eco-efficiency of this new material which featured applications span from naval to automotive and building sectors. To a minor degree, it is also a contribution in the sense that it provides life cycle inventory data on composites, which as yet are scarce in the LCA community. Life cycle assessments of bio-based polymers have shown favourable results in terms of environmental impacts and energy use compared to petroleum-based products. However, calculation of these impacts always depends on the system and boundary conditions considered during the study.


192) Segmented poly(styrene-co-vinylpyridine) as multivalent host for CdSe nanocrystal based nanocomposites

A.E.Di Mauro, M.Toscanini, D.Piovani, F.Samperi, M.L.Curria, M.Corricelli, L.De Caro, D.Siliqi, R.Comparelli, A.Agostiano, S.Destri, M.Striccoli

European Polymer Journal  60,  222-234  - 2014

Nanocomposites based on colloidal CdSe nanocrystals (NCs) and a poly(styrene-co-4-vinylpyridine), able to specifically coordinate the NC surface, have been designed and prepared. For first time, the polymer synthesis has been performed by using 2,2,5-tri-methyl-4-phenyl-3-azahexane-3-nitroxide as a mediator, increasing the percentage of 4-vinylpyridine monomeric unit, thus obtaining a random copolymer. The nanocomposite properties have been investigated as a function of NC surface chemistry and copolymer composition, by means of spectroscopic, morphological and structural characterization techniques. An improved uniformity of NC dispersion in the nanocomposite has been found at increased percentage of 4-vinylpyridine in the copolymer. The improved NC dispersion in the nanocomposite films has been discussed in terms of the ability of the copolymer to act as a multivalent ligand. The reported results offer a valuable contribution toward the design and the fabrication of innovative nanocomposite material, formed of copolymers and colloidal NCs, specifically suited for energy conversion applications.

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193) Do habitat features affect the composition of silk proteins by Namibian arid-adapted Ariadna spiders (Araneae: Segestriidae)?

E. Conti, E.Barbagallo, S.Battiato, A.Marletta, G.Costa, F.Samperi

Italian Journal of Zoology   82,  1-13  - 2014

This paper is the first to describe the silk produced by Segestriidae spiders. Field and specimen data together with webs secreted by Namibian arid-adapted Ariadna spiders were collected from different research work stations. The silks were solubilized with hexafluoroisopropanol and characterized by Fourier transform infrared (FT-IR), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and differential scanning calorimetry (DSC) techniques, in order to get data on the silk composition. FT-IR analysis confirms that proteins are the main component of the extracted materials. MALDI-TOF mass spectra of silks of three different sites (R, M and K, with three varied environmental conditions: coastal foggy area, hot central desert area and savannah) reveal the presence of low-molecular-weight (< 10,000 g/mol) proteins mostly based on glycine and alanine amino acids. Besides many peptides with identical or similar composition, other low-molar mass proteins with different compositions were also revealed in these silks. The DSC curves show that the studied silks have different melting temperature ranges. This behaviour may be due to the proteins having different molecular weight and/or different amino acid composition. The presence of small peptides with different amino acid composition could be correlated to the different habitats where the spiders live. Hypotheses linking different amino acid compositions with environmental features are suggested.


194) Covalently linked hopanoid-lipid A improves outer-membrane resistance of a Bradyrhizobium symbiont of legumes

A.Silipo, G.Vitiello, D.Gully, L.Sturiale, C.Chaintreuil, J.Fardoux, D.Gargani, H.I.Lee, G.Kulkarni, N.Busset, R.Marchetti, A.Palmigiano, H.Moll, R.Engel, R.Lanzetta, L.Paduano, M.Parrilli, W.S.Chang, O.Holst, D.K.Newman, D.Garozzo, G.D’Errico, E.Giraud, A.Molinaro

Nature Communications  5,  5106  - 2014

DOI: https://doi.org/10.1038/ncomms6106
Lipopolysaccharides (LPSs) are major components of the outer membrane of Gram-negative bacteria and are essential for their growth and survival. They act as a structural barrier and play an important role in the interaction with eukaryotic hosts. Here we demonstrate that a photosynthetic Bradyrhizobium strain, symbiont of Aeschynomene legumes, synthesizes a unique LPS bearing a hopanoid covalently attached to lipid A. Biophysical analyses of reconstituted liposomes indicate that this hopanoid-lipid A structure reinforces the stability and rigidity of the outer membrane. In addition, the bacterium produces other hopanoid molecules not linked to LPS. A hopanoid-deficient strain, lacking a squalene hopene cyclase, displays increased sensitivity to stressful conditions and reduced ability to survive intracellularly in the host plant. This unusual combination of hopanoid and LPS molecules may represent an adaptation to optimize bacterial survival in both free-living and symbiotic states.

graphical abstract



195) Thermophiles as Potential Source of Novel Endotoxin Antagonists: the Full Structure and Bioactivity of theLipo-oligosaccharide from Thermomonas hydrothermalis

F.Di Lorenzo, I.Paciello, L.L.Fazio, L.Albuquerque, L.Sturiale, M.S.Da Costa, R.Lanzetta, M.Parrilli, D.Garozzo, M.L.Bernardini, A.Silipo, A.Molinaro

Chembiochem  15(14),  2146-2155  - 2014

Thermomonas hydrothermalis is a Gram-negative thermophilic bacterium that is able to live at 50 °C. This ability is attributed to chemical modifications, involving those to bacterial cell-wall components, such as proteins and (glyco)lipids. As the main component of the outer membrane of Gram-negative bacteria, lipopolysaccharides (LPSs) are exposed to the environment, thus they can undergo structural chemical changes to allow thermophilic bacteria to live at their optimal growth temperature. Furthermore, as one of the major target of the eukaryotic innate immune system, LPS elicits host immune response in a structure-dependent mode; thus the uncommon chemical features of thermophilic bacterial LPSs might exert a different biological action on the innate immune system-an antagonistic effect, as shown in studies of LPS structure-activity relationship in the ongoing research into antagonist LPS candidates. Here, we report the complete structural and biological activity analysis of the lipo-oligosaccharide isolated from Thermomonas hydrothermalis, achieved by a multidisciplinary approach (chemical analysis, NMR, MALDI MS and cellular immunology). We demonstrate a tricky and interesting structure combined with a very interesting effect on human innate immunity.

grafical abstract



196) Functionalization of aliphatic polyesters by nitroxide radical coupling

F.Cicogna, S.Coiai, P.Rizzarelli, S.Carroccio, C.Gambarotti, I.Domenichelli, C.Yang, N.Tz.Dintcheva, G.Filippone, C.Pinzino, E.Passaglia

Polymer Chemistry  5,  5656-5667  - 2014

Functionalized poly(butylene succinate) (PBS) samples were prepared by a post-polymerization method based on the coupling reaction between TEMPO derivatives bearing different functionalities and PBS macroradicals generated by H-abstraction using a peroxide. 4-Benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (BzO-TEMPO) and 4-(1-naphthoate)-2,2,6,6-tetramethylpiperidine-1-oxyl (NfO-TEMPO), a pro-fluorescent nitroxide, were successfully grafted on PBS, as revealed by MALDI TOF MS and UV-Vis spectroscopy. The functionalization degrees were accurately determined by UV-Vis analysis and confirmed by 1H-NMR spectroscopy. The grafting site was identified by combining theoretical calculations with experimental evidence. This evidence was collected by both EPR analysis of a functionalized sample subjected to controlled heating in the EPR cavity, and by 1H-NMR spectroscopy. Our functionalization method, which was also tested for poly(lactic acid) (PLA), preserves the original polymer structure. This avoids the crosslinking-branching side reaction, which generally affects the free radical treatment of biodegradable aliphatic polyesters. In addition, using a pro-fluorescent nitroxide to form functionalized samples is a significant step towards unambiguously demonstrating the radical grafting on these types of polymer. It also proves that well-defined fluorescently labeled biodegradable polyesters can be tailored.

graphical abstract



197) Coffee enhances the expression of chaperones and antioxidant proteins in rats with nonalcoholic fatty liver disease

F.Salomone, G.Li Volti, P.Vitaglione, F.Morisco, V.Fogliano, A.Zappalà, A.Palmigiano, D.Garozzo, N.Caporaso, G.D’Argenio, F.Galvano

Translational Research  163,  593-602  - 2014

Coffee consumption is inversely related to the degree of liver injury in patients with nonalcoholic fatty liver disease (NAFLD). Molecular mediators contributing to coffee’s beneficial effects in NAFLD remain to be elucidated. In this study, we administrated decaffeinated espresso coffee or vehicle to rats fed an high-fat diet (HFD) for 12 weeks and examined the effects of coffee on liver injury by using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) proteomic analysis combined with mass spectrometry. Rats fed an HFD and water developed panacinar steatosis, lobular inflammation, and mild fibrosis, whereas rats fed an HFD and coffee exhibited only mild steatosis. Coffee consumption increased liver expression of the endoplasmic reticulum chaperones glucose-related protein 78 and protein disulfide-isomerase A3; similarly, coffee drinking enhanced the expression of the mitochondrial chaperones heat stress protein 70 and DJ-1. Furthermore, in agreement with reduced hepatic levels of 8-isoprostanes and 8-hydroxy-2’-deoxyguanosine, proteomic analysis showed that coffee consumption induces the expression of master regulators of redox status (i.e., peroxiredoxin 1, glutathione S-transferase α2, and D-dopachrome tautomerase). Last, proteomics revealed an association of coffee intake with decreased expression of electron transfer flavoprotein subunit α, a component of the mitochondrial respiratory chain, involved in de novo lipogenesis. In this study, we were able to identify by proteomic analysis the stress proteins mediating the antioxidant effects of coffee; moreover, we establish for the first time the contribution of specific coffee-induced endoplasmic reticulum and mitochondrial chaperones ensuring correct protein folding and degradation in the liver.


198) α-Tocopherol-induced radical scavenging activity in carbon nanotubes for thermo-oxidation resistant ultra-high molecular weight polyethylene-based nanocomposites

N.Tz.Dintchevaa, R.Arrigo, C.Gambarotti, S.Carroccio, G.Filippone, F.Cicogna, M. Guenzi

Carbon  74,  14-21  - 2014

α-Tocopherol, a natural antioxidant molecule, was physically immobilized on the outer surface of multi-walled carbon nanotubes (CNTs), and the resulting functionalised particles (f-CNTs) were dispersed in ultra-high molecular weight polyethylene aiming at improving its thermo-oxidation resistance. The success of the functionalization was assessed through spectroscopic and thermal analysis, and the influence of the filler on the thermo-oxidative stability of the nanocomposites was investigated through rheological analyses and infrared spectroscopy. We found that the addition of only 1 wt. % of f-CNTs brings about a surprisingly high oxidation resistance, with a five/ten-fold increase of the induction time of the degradation phenomena. Rather than to the inherent stabilizing action of the α-tocopherol, such a notable result is believed to be due to its specific chemical interactions with the CNTs, which could exhibit a considerable radical scavenging activity due to the formation of structural defects on their outer surface. The latter represent acceptor-like localized states, which radically improve the thermo-oxidative resistance of the f-CNTs-based polymer nanocomposites.


199) Identification of human tear fluid biomarkers in vernal keratoconjunctivitis using iTRAQ quantitative proteomics

A.Leonardi, A.Palmigiano, E.Mazzola, A.Messina, E.Milazzo, M.Bortolotti, D.Garozzo

Allergy  69(2),  254-260  - 2014

DOI: https://doi.org/10.1111/all.12331
BACKGROUND: Understanding and treating vernal keratoconjunctivitis (VKC) has been a challenge because the pathogenesis is unclear and antiallergic therapy often unsuccessful. The aim of the study was to analyze peptide profiles in human tears using mass spectrometry to elucidate compositional differences between healthy subjects and patients affected by VKC.
METHODS: Tears were collected from healthy subjects and VKC patients. Digested samples were treated with iTRAQ (isobaric tag for relative and absolute quantitation). Separation of tryptic peptides was realized using a MicroHPLC interfaced with a microfraction collector. MS and MS/MS mass spectra were performed using a MALDI TOF/TOF 4800 Applied Biosystem spectrometer. Protein PilotTM software with ParagonTM algorithm v4.1.46 or GPSTM with Mascot engine was used as search engines with SwissProt or IPI human as the databases.
RESULTS: A significant number of peptides were examined, and 78 proteins were successfully identified. In all VKC samples, levels of serum albumin, transferrin, and hemopexin were found up to 100 times higher than control tear levels and correlated to the severity of disease. Hemopexin, transferrin, mammaglobin B, and secretoglobin 1D were found significantly over-expressed in VKC samples compared with the control samples. Tear samples from patients treated with topical cyclosporine or corticosteroids showed a dramatic reduction in these protein levels.
CONCLUSIONS:LC MALDI MS and isobaric tag for relative and absolute quantitation technique may be useful in the quantitative and qualitative characterization of the peptidoma of human tears. These techniques may identify target proteins to be used in the diagnosis and management of VKC and other inflammatory ocular surface conditions.

graphical abstract



200) Heat-Resistant Fully Bio-Based Nanocomposite Blends

A.Nuzzo, S.Coiai, S.Carroccio, N.Tz.Dintcheva, C.Gambarotti, G.Filippone

Macromolecular Materials and Engineering  299,  31-40  - 2014

Poly(lactic acid) (PLA) is melt mixed with polyamide 11 (PA11) to obtain a heat-resistant fully bio-based blend with PLA as the dominant component. The goal is achieved by adding small amounts of organoclay (OMMT), which is used to manipulate the blend microstructure. The selective positioning of the OMMT inside the PA11 and at the PLA/PA11 interface turns the blend morphology from drop/matrix into co-continuous at high PLA content (70 wt%). The OMMT-rich PA11 framework that interpenetrates the major PLA phase effectively contributes to bear stresses, and the nanocomposite blend keeps its structural integrity up to ≈160°C, i.e., about 100°C above the PLA glass transition.

Cover Picture: Macromol. Mater. Eng. 1(2014)



201) Modern mass spectrometry in the characterization and degradation of biodegradable polymers

P.Rizzarelli, S.Carroccio

Analytica Chimica Acta  808,  18-43  - 2014

In the last decades, the solid-waste management related to the extensively growing production of plastic materials, in concert with their durability, have stimulated increasing interest in biodegradable polymers. At present, a variety of biodegradable polymers has already been introduced onto the market and can now be competitive with non biodegradable thermoplastics in different fields (packaging, biomedical, textile, etc.). However, a significant economical effort is still directed in tailoring structural properties in order to further broaden the range of applications without impairing biodegradation. Improving the performance of biodegradable materials requires a good characterization of both physico-chemical and mechanical parameters. Polymer analysis can involve many different features including detailed characterization of chemical structures and compositions as well as average molecular mass determination. It is of outstanding importance in troubleshooting of a polymer manufacturing process and for quality control, especially in biomedical applications. This review describes recent trends in the structural characterization of biodegradable materials by modern mass spectrometry (MS). It provides an overview of the analytical tools used to evaluate their degradation. Several successful applications of MALDI-TOF MS (matrix assisted laser desorption ionization time of flight) and ESI MS (electrospray mass spectrometry) for the determination of the structural architecture of biodegradable macromolecules, including their topology, composition, chemical structure of the end groups have been reported. However, MS methodologies have been recently applied to evaluate the biodegradation of polymeric materials. ESI MS represents the most useful technique for characterizing water-soluble polymers possessing different end group structures, with the advantage of being easily interfaced with solution-based separation techniques such as high-performance liquid chromatography (HPLC).

grafical abstract

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202) Synthesis and characterization of copolyformals containing electron-rich or electron-poor porphyrin units in the main chain and their use as sensors

P.Mineo, E.Scamporrino, E.Spina, D.Vitalini

Sensors and Actuators B: Chemical  188,  1284-1292  - 2013

In this study two new porphyrin monomers, 5,15-di(pentafluorophenyl)-10,20-di(ρ-hydroxyphenyl)-porphyrin and 5,15-di(pentabutoxyphenyl)-10,20-di(ρ-hydroxyphenyl)-porphyrin, were synthesized and characterized by NMR and MALDI-TOF mass spectrometry. The chemical characteristics of these monomers are strongly influenced by their respective electronic distribution which, in turn, is determined by the phenyl ring substituents. By reaction with different amounts of 1,20-di(bisphenoxy-A)-eicosane in presence of dibromomethane, copolyformals containing porphyrin dyes at different percentages were subsequently obtained. The sensing responses of the synthesized copolymers were tested with the following analytes: acetic, trifluoroacetic and hydrochloridic acids and nitrogen dioxide. Our data indicate that porphyrin units interact with analytes in a reversible fashion, it being understood that the decabuthoxy porphyrin derivative has a greater affinity than the other one with both acids and NO2.

grafical abstract



203) MAN1B1 Deficiency: An Unexpected CDG-II

D.Rymen, R.Peanne, M.B.Millón, V.Race, L.Sturiale, D.Garozzo, P.Mills, P.Clayton, C.G.Asteggiano, D.Quelhas, A.Cansu, E.Martins, M.C.Nassogne, M.Gonçalves-Rocha, H.Topaloglu, J.Jaeken, F.Foulquier, G.Matthijs

Plos Genetics  9,  1-13  - 2013

Congenital disorders of glycosylation (CDG) are a group of rare metabolic diseases, due to impaired protein and lipid glycosylation. In the present study, exome sequencing was used to identify MAN1B1 as the culprit gene in an unsolved CDGII patient. Subsequently, 6 additional cases with MAN1B1-CDG were found. All individuals presented slight facial dysmorphism, psychomotor retardation and truncal obesity. Generally, MAN1B1 is believed to be an ER resident alpha-1,2-mannosidase acting as a key factor in glycoprotein quality control by targeting misfolded proteins for ER-associated degradation (ERAD). However, recent studies indicated a Golgi localization of the endogenous MAN1B1, suggesting a more complex role for MAN1B1 in quality control. We were able to confirm that MAN1B1 is indeed localized to the Golgi complex instead of the ER. Furthermore, we observed an altered Golgi morphology in all patients’ cells, with marked dilatation and fragmentation. We hypothesize that part of the phenotype is associated to this Golgi disruption. In conclusion, we linked mutations in MAN1B1 to a Golgi glycosylation disorder. Additionally, our results support the recent findings on MAN1B1 localization. However, more work is needed to pinpoint the exact function of MAN1B1 in glycoprotein quality control, and to understand the pathophysiology of its deficiency.


204) Characterization of biodegradable poly(3-hydroxybutyrate-co-butyleneadipate) copolymers obtained from their homopolymers by microwave-assisted transesterification

G.Impallomeni, G.M.Carnemolla, G.Puzzo, A.Ballistreri, L.Martino, M.Scandola

Polymer  54(1),  65-74  - 2013

Copolymers containing (R)-3-hydroxybutyric acid (HB), 1,4-butanediol (B), and adipic acid (A) were synthesized by microwave-assisted transesterification of biodegradable poly(R-3-hydroxybutyrate) (PHB) and poly(1,4-butyleneadipate) (PBA) in solution at different reaction times, composition of the starting mixture, and amount of 4-toluenesulfonic acid, used as a catalyst. The copolyesters were characterized with regard to their molecular weights, thermal properties, molar composition, and average block length of repeating units by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXS), 1H-NMR, and 13C-NMR, respectively. Random and microblock copolymers could be obtained depending on experimental conditions, with weight average molecular weight of up to 17,000. The glass transition temperature (Tg) of all samples lay in the range between the Tgs of PBA and PHB, while their structure varied from partially crystalline to totally amorphous. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectra of copolymers allowed us to ascertain that they were hydroxyl and carboxyl chain-end terminated.

Graphical Abstract



205) Combining spontaneous polymerization and click reactions for the synthesis of polymer brushes: a "grafting onto" approach.

A.Cappelli, G.Grisci, M.Paolino, F.Castriconi, G.Giuliani, A.Donati, S.Lamponi, R.Mendichi, A.C.Boccia, F.Samperi, S.Battiato, E.Paccagnini, M.Gentile, M.Licciardi, G.Giammona, S.Vomero

Chemistry-A European Journal  19(29),  9710-9721  - 2013

Two novel benzofulvene monomers bearing propargyl or allyl groups have been synthesized by means of readily accessible reactions, and were found to polymerize spontaneously by solvent removal, in the apparent absence of catalysts or initiators, to give the corresponding polybenzofulvene derivatives bearing clickable propargyl or allyl moieties. The clickable propargyl and allyl groups were exploited in appropriate click reactions to develop a powerful and versatile "grafting onto" synthetic methodology for obtaining tailored polymer brushes.


206) Intracellular Shigella remodels its LPS to dampen the innate immune recognition and evade inflammasome activation

I.Paciello, A.Silipo, L.Lembo-Fazio, L.Curcurù, A.Zumsteg, G.Noël, V.Ciancarella, L.Sturiale, A.Molinaro, M.L.Bernardini

Proceedings of the National Academy of Sciences of The United States of America  110(46),  E4345-E4354  - 2013

LPS is a potent bacterial effector triggering the activation of the innate immune system following binding with the complex CD14, myeloid differentiation protein 2, and Toll-like receptor 4. The LPS of the enteropathogen Shigella flexneri is a hexa-acylated isoform possessing an optimal inflammatory activity. Symptoms of shigellosis are produced by severe inflammation caused by the invasion process of Shigella in colonic and rectal mucosa. Here we addressed the question of the role played by the Shigella LPS in eliciting a dysregulated inflammatory response of the host. We unveil that (i) Shigella is able to modify the LPS composition, e.g., the lipid A and core domains, during proliferation within epithelial cells; (ii) the LPS of intracellular bacteria (iLPS) and that of bacteria grown in laboratory medium differ in the number of acyl chains in lipid A, with iLPS being the hypoacylated; (iii) the immunopotential of iLPS is dramatically lower than that of bacteria grown in laboratory medium; (iv) both LPS forms mainly signal through the Toll-like receptor 4/myeloid differentiation primary response gene 88 pathway; (v) iLPS down-regulates the inflammasome-mediated release of IL-1β in Shigella-infected macrophages; and (vi) iLPS exhibits a reduced capacity to prime polymorfonuclear cells for an oxidative burst. We propose a working model whereby the two forms of LPS might govern different steps of the invasive process of Shigella. In the first phases, the bacteria, decorated with hypoacylated LPS, are able to lower the immune system surveillance, whereas, in the late phases, shigellae harboring immunopotent LPS are fully recognized by the immune system, which can then successfully resolve the infection.


207) Mutations in SLC35A3 cause autism spectrum disorder, epilepsy and arthrogryposis

S.Edvardson, A.Ashikov, C.Jalas, L.Sturiale, A.Shaag, A.Fedick, N.R.Treff, D.Garozzo, R.Gerardy-Schahn, O.Elpeleg

Journal of Medical Genetics   50(11),  733-739  - 2013

Background
The heritability of autism spectrum disorder is currently estimated at 55%. Identification of the molecular basis of patients with syndromic autism extends our understanding of the pathogenesis of autism in general. The objective of this study was to find the gene mutated in eight patients from a large kindred, who suffered from autism spectrum disorder, arthrogryposis and epilepsy.
Methods and results
By linkage analysis and exome sequencing, we identified deleterious mutations in SLC35A3 in these patients. SLC35A3 encodes the major Golgi uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) transporter. In Golgi vesicles isolated from patient fibroblasts the transport of the respective nucleotide sugar was significantly reduced causing a massive decrease in the content of cell surface expressed highly branched N-glycans and a concomitant sharp increase of lower branched glycoforms.
Conclusions
Spontaneous mutation in SLC35A3 has been discovered in cattle worldwide, recapitulating the human phenotype with arthrogryposis and additional skeletal defects known as Complex Vertebral Malformation syndrome. The skeletal anomalies in the mutant cattle and in our patients, and perhaps even the neurological symptoms are likely the consequence of the lack of high-branched N-glycans and the concomitant abundance of lower-branched glycoforms at the cell surface. This pattern has previously been associated with growth arrest and induction of differentiation. With this study, we add SLC35A3 to the gene list of autism spectrum disorders, and underscore the crucial importance of UDP-GlcNAc in the regulation of the N-glycan branching pathway in the Golgi apparatus.

November cover of JMG



208) First Self-Adjuvant Multicomponent Potential Vaccine Candidates by Tethering of Four or Eight MUC1 Antigenic Immunodominant PDTRP Units on a Calixarene Platform: Synthesis and Biological Evaluation

C.Geraci, G.M.L.Consoli, G.Granata, E.Galante, A.Palmigiano, M.Pappalardo, S.D.Di Puma, A.Spadaro

Bioconjugate Chemistry  24(10),  1710-1720  - 2013

MUC1 protein overexpressed in human epithelial carcinoma is a target in development of novel anticancer vaccines. Multiple units of immunodominant B-cell epitope PDTRP MUC1 core sequence were conjugated to calix[4,8]arene platforms containing TLR2 ligand, to produce two novel anticancer self-adjuvant vaccine candidates. The immunogenicity of the synthetic constructs was investigated by immunization of mice in vivo. ELISA assay evidenced that the vaccine candidates stimulate anti MUC1 IgG antibody production (major for the octavalent construct) and no additive effect but a multivalency effect was observed when compared to an analogous monovalent. Octa- and tetravalent constructs lacking in PDTRP peptide moieties did not show anti MUC1 IgG antibody production in mice. The antibodies induced by the synthesized constructs are able to recognize the MUC1 structures present on MCF7 tumor cells. The results display that calixarenes are convenient platforms for building multicomponent self-adjuvant vaccine constructs promising as immunotherapeutic anticancer agents.

Graphical Abstract



209) Matrix-assisted laser desorption ionization time-of-flight/time-offlight tandem mass spectra of biodegradable polybutylenesuccinate

P.Rizzarelli

Rapid Communications in Mass Spectrometry  27,  2213-2225  - 2013

RATIONALE
Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight/Time-Of-Flight Tandem Mass Spectrometry (MALDI-TOF MS/MS) was employed to analyze five poly(butylene succinate) (PBSu) oligomers and to investigate their fragmentation pathways.
METHODS
MALDI-TOF MS/MS analysis was performed on cyclic and linear oligomers terminated by dicarboxyl groups, carboxyl and hydroxyl groups, hydroxyl and olefin groups, and dihydroxyl groups. The sodium adduct ions of these oligomers were selected as precursor ions. Experiments were carried out with and without argon as the collision gas.
RESULTS
A β-hydrogen transfer rearrangement, leading to the selective cleavage of the -O-CH2-bonds, and cleavage of the -CH2-CO-bonds, the ester bonds, and the -CH2-CH2-bonds in the diol moiety were observed. Two fragmentation mechanisms, correlated to the end-group structure of the precursor ions, were also proposed. The detection of cyclic anhydrides was related to the presence of succinic acid terminal groups. The formation of microcyclic oligoesters probably occurred via an intramolecular transesterification mechanism involving a hydroxyl end group.
CONCLUSIONS
A β-hydrogen transfer rearrangement has been proposed as the main fragmentation mechanism occurring in PBSu without using the collision gas. Cleavages of almost all types of bonds take place in the MALDI CID experiments. According to the structures of the most abundant product ions, six fragmentation pathways have been proposed when using argon as the collision gas. Two fragmentation mechanisms were suggested as being correlated to the end-group structure of the precursor ions.


210) Perfluorinated polymer with unexpectedly efficient deep blue electroluminescence for full-colour OLED displays and light therapy applications

U.Giovanella, Ch.Botta, F.Galeotti, B.Vercelli, S.Battiato, M.C.Pasini

Journal of Materials Chemistry C  1,  5322-5329  - 2013

The fluorinated phenylene unit is used as a building block for an all-conjugated fluorene-based alternating copolymer (PFO-TFP). The synthesis, carried out by an optimized Suzuki cross-coupling, produces an extremely high purity compound with a series of intriguing properties. Firstly, a blue-shift of the absorption and emission spectra with respect to the parent polymer is achieved. Secondly, the photoluminescence (PL) quantum yields (QYs) of the solution, as high as 68%, are surprisingly retained in the solid-state. Finally, an improved colour stability of the film with respect to unsubstituted polymers, investigated by means of cyclic voltammetry and exposure to ultraviolet radiation, is observed. The PFO-TFP tested as an undoped active layer in a polymer light-emitting diode (PLED) shows a highly desirable pure deep blue 405 nm electroluminescence, CIE = (0.17; 0.06) and a remarkable 5.03% external quantum efficiency, thus fulfilling the requirements for both full-colour displays and biomedical applications. To date, fluorine atom incorporation has been successfully employed in the synthesis of high-performing polymers for organic field-effect transistors and photovoltaics. We give the first unambiguous proof of its efficacy in achieving pure deep blue electroluminescence in a highly efficient and stable PLED, which is competitive with the best reported conjugated oligomer-based devices.


211) Structure of N-linked oligosaccharides attached to chlorovirus PBCV-1 major capsid protein reveals unusual class of complex N-glycans

C.De Castro, A.Molinaro, F.Piacente, J.R.Gurnon, L.Sturiale, A.Palmigiano, R.Lanzetta, M.Parrilli, D.Garozzo, M.G.Tonetti, J.L.Van Etten

Proceedings of the National Academy of Sciences of The United States of America  110,  13956-13960  - 2013

DOI: https://doi.org/10.1073/pnas.1313005110
The major capsid protein Vp54 from the prototype chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) contains four Asnlinked glycans. The structure of the four N-linked oligosaccharides and the type of substitution at each glycosylation site was determined by chemical, spectroscopic, and spectrometric analyses. Vp54 glycosylation is unusual in many ways, including: (i) unlike most viruses, PBCV-1 encodes most, if not all, of the machinery to glycosylate its major capsid protein; (ii) the glycans are attached to the protein by a β-glucose linkage; (iii) the Asn-linked glycans are not located in a typical N-X-(T/S) consensus site; and (iv) the process probably occurs in the cytoplasm. The four glycoforms share a common core structure, and the differences are related to the nonstoichiometric presence of two monosaccharides. The most abundant glycoform consists of nine neutral monosaccharide residues, organized in a highly branched fashion. Among the most distinctive features of the glycoforms are (i) a dimethylated rhamnose as the capping residue of the main chain, (ii) a yperbranched fucose unit, and (iii) two rhamnose residues with opposite absolute configurations. These glycoforms differ from what has been reported so far in the three domains of life. Considering that chloroviruses and other members of the family Phycodnaviridae may have a long evolutionary history, we suggest that the chlorovirus glycosylation pathway is ancient, possibly existing before the development of the endoplasmic reticulum and Golgi pathway, and involves still unexplored mechanisms.


212) Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the characterization of functionalized carbon nanotubes

S.Carroccio, G.Curcuruto, N.Tz.Dintcheva, C.Gambarotti, S.Coiai, G.Filippone

Rapid Communications in Mass Spectrometry  27,  1359-1366  - 2013

RATIONALE: Functionalization of carbon nanotubes (CNTs) generates complex systems that require the development of suitable characterization protocols. New techniques have been explored, and existing analytical and spectroscopic methods to characterize functionalized CNTs have been adapted. Presently, chemical characterization of functionalized CNTs (f-CNTs) remains a difficult task.
METHODS: Matrix-assisted laser desorption/ionization (MALDI) analysis is performed on f-MWCNT samples prepared via grafting or absorption of anti-oxidant (AO) molecules on both MWCNT-COOH and MWCNT-OH. Covalently functionalized MWCNTs were subjected to thermal degradation and/or hydrolysis reaction before analysis, whereas MWCNTs with a physical adsorption of the functionalizing molecules were directly spotted in the target sample. Noteworthy, in our approach f-MWCNTs constitute at the same time analyte and MALDI matrix.
RESULTS: The identification of functionalizing AO molecules is ascertained after degradation or hydrolysis reactions in both MWCNT-COOH and MWCNT-OH grafted samples. Absorbed AO molecules, as well as organic impurities derived from grafting reactions, are also revealed by MALDI MS without any preliminary cleavage reaction.
CONCLUSIONS: A simple MALDI-TOF mass spectrometry method permits to obtain the unambiguous discrimination between grafted or adsorbed functionalized molecules onto the surface of MWCNTs.


213) Chemistry and Biology of the Potent Endotoxin from a Burkholderia dolosa Clinical Isolate from a Cystic Fibrosis Patient

F.Di Lorenzo, L.Sturiale, A.Palmigiano, L.Lembo-Fazio, I.Paciello, C.P.Coutinho, I.S -Correia, M.L.Bernardini, R.Lanzetta, D.Garozzo, A.Silipo, A.Molinaro

ChemBioChem  14,  1105-1115  - 2013

This is the first report of the chemical and biological properties of the lipooligosaccharide (LOS) endotoxin isolated from Burkholderia dolosa IST4208, an isolate recovered from a cystic fibrosis (CF) patient in a Portuguese CF center. B. dolosa is a member of the Burkholderia cepacia complex, a group of closely related species that are highly problematic and opportunistic pathogens in CF. B. dolosa infection leads to accelerated loss of lung function and decreased survival. The structural determination of its endotoxin was achieved using a combination of chemistry and spectroscopy, and has revealed a novel endotoxin structure. The purified LOS was tested for its immunostimulatory activity on human HEK 293 cells expressing TLR-4, MD-2, and CD-14. In these assays, the LOS showed strong proinflammatory activity.


214) New Amphiphilic Conjugates of Amino- Poly(ethylene glycols) With Lipoamino Acids as Surface Modifiers of Colloidal Drug Carriers

R.Pignatello, V.Pantò, G.Impallomeni, G.M.Carnemolla, C.Carbone, G.Puglisi

Macromolecular Chemistry and Physics  214,  46-55  - 2013

Poly(ethylene glycol) (PEG2000) polymers containing one or two amine residues are linked to α-lipoamino acids (LAA) to produce mono- and homo-disubstituted PEG-LAA conjugates as new materials for the surface coating of colloidal drug carriers. Conjugates are characterized by FT-IR, 1H-NMR, and MALDI-TOF mass spectrometry. Differential scanning calorimetry studies are performed to assess the interaction of PEG2000-LAAs with a biomembrane model (dipalmitoylphosphatidylcholine multilamellar liposomes). Whereas the parent PEGs affect only the superficial structure of the bilayers, the amphiphilic PEG-LAA conjugates exert a modulated perturbing effect on the thermotropic profile of liposomes. A molar concentration between 5% and 10% is individuated as the more suitable to produce stable vesicles.

Graphical Abstract



215) Structure and Immunological Activity of the Lipopolysaccharide Isolated from the Species Alkalimonas delamerensis

A.Silipo, F.Di Lorenzo, L.Lembo Fazio, I.Paciello, L.Sturiale, A.Palmigiano, M.Parrilli, W.D.Grant, D.Garozzo, R.Lanzetta, M.L.Bernardini, A.Molinaro

European Journal of Organic Chemistry  2013(13),  2653-2665  - 2013

We have defined the complete structure and assessed the biological activity of the lipopolysaccharide (LPS) from Alkalimonas delamerensis, an alkaliphilic bacterium isolated from soda lakes in China and East Africa. The structural determination, which was achieved by the use of chemical, spectroscopic and spectrometric approaches, indicates a novel Rough type lipopolysaccharide that is rich in negatively charged groups in the lipid A inner core region. The proinflammatory activity of the pure lipopolysaccharide has also been defined by testing the LPS as a stimulant in human HEK293 cells, which express the CD14/MD2/TLR4 complex (HEK293-hTLR4), and in bone marrow-derived macrophages.


216) Air quality biomonitoring through pollen viability of Fabaceae

A.Duro, V.Piccione, D.Zampino

Environmental Monitoring and Assessment  185,  3803-3817  - 2013

In this study, pollen viability and germination of three plant species, Cercis siliquastrum L., Robinia pseudoacacia L., and Spartium junceum L., belonging to the Fabaceae family, was evaluated in sites with different intensity of road traffic, constantly monitored with continuous analysers for air pollutants (carbon monoxide (CO), sulphur dioxide (SO2), and nitrogen dioxide (NO2)) by the Municipality of Catania. Two sites, in which road traffic was absent, were selected, too. The percentages of viable pollen by 2,3,5-trypheniltetrazolium chloride (TTC) test ranged from 59.0 to 90.2 % in C. siliquastrum, from 61.5 to 83.5 % in S. junceum and from 67.5 to 84.3 % in R. pseudoacacia. The percentages of germination varied from 41.0 to 72.7% in C. siliquastrum, from 42.0 to 64.7 % in S. junceum and from 38.3 to 66.3 % in R. pseudoacacia. The highest percentages of viable pollens were found in no-road traffic stations by either TTC or germination tests, while the lowest values were detected in a site characterised by heavy road traffic. In the monitored period (2007-2009), pollen viability, germinability and tube length of C. siliquastrum resulted in a significant negative correlation to CO, SO2 and NO2, whereas data from TTC and germination tests on S. junceum and R. pseudoacacia pollens were not well correlated to air pollutants. The results showed that pollen viability, germination and tube growth in C. siliquastrum were affected by air pollution. S. junceum and R. pseudoacacia were not very influenced by air pollutants, suggesting a different pollen sensitivity of these species.


217) GLYCOSYLATION DEFECTS AND EPILEPSY

A.Fiumara, L.Sturiale, M.Cocuzza, D.Castiglione, G.Del Campo, R.Barone

Journal of Inherited metabolic disease  35,  S111  - 2012

We report a new subtype of non-neurological congenital disorders of glycosylation (CDG) involving the impaired cytoplasmic biosynthesis of nucleotide sugars needed for glycan biosynthesis. A patient resented with muscle fatigue, elevated creatine kinase, growth hormone deficiency, and first branchial arch syndrome. These findings, together with the abnormal type II plasma transferrin isoform profile detected, was compatible with a CDG. Functional testing and clinical analyses suggested a deficiency in the interconversion of glucose-1-phosphate and glucose-6-phosphate catalysed by phosphoglucomutase (PGM1), a problem previously described as glycogenosis type XIV. PGM1 activity in patient-derived fibroblasts was significantly reduced, as was the quantity of immunoreactive PGM1 protein. Mutation analysis of PGM1 and subsequent functional analysis investigating transient expression of PGM1 in immortalized patient fibroblasts, followed by ex vivo splicing assays using minigenes, allowed the characterization of two novel pathogenic mutations: c.871 G>A (p.Gly291Arg) and c.1144+3A>T. The latter represents a severe splicing mutation leading to the out-of-frame skipping of exon 7 and the formation of a truncated protein (p.Arg343fs). MALDI mass spectra of permethylated protein Nglycans from the patient's serum suggested a marked hypoglycosylation defect. The present findings confirm that, in addition to a rare muscular glycolytic defect, PGM1 deficiency causes a non-neurological disorder of glycosylation.


218) COG5-CDG: expanding the clinical spectrum

D.Rymen, L.Keldermans, V.Race, L.Régal, N.Deconinck, C.Dionisi-Vici, C.Fung, L.Sturiale, C.Rosnoblet, F.Foulquier, G.Matthijs, J.Jaeken

Orphanet Journal of Rare Diseases  7  - 2012

Background

The Conserved Oligomeric Golgi (COG) complex is involved in the retrograde trafficking of Golgi components, thereby affecting the localization of Golgi glycosyltransferases. Deficiency of a COG-subunit leads to defective protein glycosylation, and thus Congenital Disorders of Glycosylation (CDG). Mutations in subunits 1, 4, 5, 6, 7 and 8 have been associated with CDG-II. The first patient with COG5-CDG was recently described (Paesold- Burda et al. Hum Mol Genet 2009; 18:4350?6). Contrary to most other COG-CDG cases, the patient presented a mild/moderate phenotype, i.e. moderate psychomotor retardation with language delay, truncal ataxia and slight hypotonia.

Methods

CDG-IIx patients from our database were screened for mutations in COG5. Clinical data were compared. Brefeldin A treatment of fibroblasts and immunoblotting experiments were performed to support the diagnosis.

Results and conclusion

We identified five new patients with proven COG5 deficiency. We conclude that the clinical picture is not always as mild as previously described. It rather comprises a broad spectrum with phenotypes ranging from mild to very severe. Interestingly, on a clinical basis some of the patients present a significant overlap with COG7-CDG, a finding which can probably be explained by subunit interactions at the protein level.


219) Role of 2-Hydroxyethyl End Group on the Thermal Degradation of Poly(ethylene terephthalate) and Reactive Melt Mixing of Poly(ethylene terephthalate)/ Poly(ethylene naphthalate) Blends

I.Blanco, G.Cicala, C.L.Restuccia, A.Latteri, S.Battiato, A.Scamporrino, F.Samperi

Polymer Engineering and Science  52,  2498-2505  - 2012

In an attempt to minimize the acetaldehyde formation at the processing temperatures (280-300°C) and the outer-inner transesterification reactions in the poly (ethylene terephthalate) (PET)-poly(ethylene naphthalate) (PEN) melt-mixed blends, the hydroxyl chain ends of PET were capped using benzoyl chloride. The thermal characterization of the melt-mixed PET-PEN blends at 300°C, as well as that of the corresponding homopolymers, was performed. Degradations were carried out under dynamic heating and isothermal conditions in both flowing nitrogen and static air atmosphere. The initial decomposition temperatures (Ti) were determined to draw useful information about the overall thermal stability of the studied compounds. Also, the glass transition temperature (Tg) was determined by finding data, indicating that the end-capped copolymers showed a higher degradation stability compared to the unmodified PET and, when blended with PEN, seemed to be efficient in slowing the kinetic of transesterification leading to, for a finite time, the formation of block copolymers, as determined by 1H-NMR analysis. This is strong and direct evidence that the endcapping of the -OH chain ends influences the mechanism and the kinetic of transesterification.


220) Deficiency of subunit 6 of the conserved oligomeric golgi complex (COG6-CDG): second patient, different phenotype

P.J.Goyens, S.Huybrechts , C.De Laet, P.Bontems, S.Rooze, H.Souayah , Y.Sznajer, L.Sturiale, D.Garozzo, G.Matthijs, A.Ferster, J.Jaeken

Journal of Inherited metabolic disease  35,  S114  - 2012

CDG-II due to defects in one of the eight subunits of the COG-complex represent a novel group of protein glycosylation disorders. We describe a 42-month-old girl with COG6 deficiency. First child of healthy consanguineous Moroccan parents, she presented at birth with dysmorphic features: microcephaly, polydactyly, broad palpebral fissures, retrognathia and anal anteposition. The clinical phenotype was further characterised by multiorgan involvement including mild psychomotor retardation, inflammatory bowel disease, micronodular liver cirrhosis, proximal tubulopathy, associated with life-threatening and recurrent infections due to combined Tand B-cell dysfunction and neutrophil dysfunction. No bleeding tendency was observed. Mutation analysis showed the patient to be homozygous for the c.G1646T mutation in the COG6 gene. She is the second reported patient with COG6 deficiency and carrier of the same mutation as the index patient (Lübbehusen et al, 2010). Although both patients are homozygous for the same mutation, they present a markedly different clinical picture. Indeed immunodeficiency as well as inflammatory bowel disease has not been described previously in patients with any COG-CDG. Mutation c.G1646T produces instability of mRNA rather than a degradation of mutated protein; individual factors might therefore interfere with the degradation speed of mRNA and contribute to the inter-individual phenotypical variation.


221) DPM2-CDG: A Muscular Dystrophy-Dystroglycanopathy Syndrome with Severe Epilepsy

R.Barone, Ch.Aiello, V.Race, E.Morava, F.Foulquier, M.Riemersma, Ch.Passarelli, D.Concolino, M.Carella, F.Santorelli, W.Vleugels, E.Mercuri, D.Garozzo, L.Sturiale, S.Messina, J.Jaeken, A.Fiumara, R.A.Wevers, E.Bertini, G.Matthijs, D. J.Lefeber

Annals of Neurology  72,  550-558  - 2012

Objective:
Congenital disorders of glycosylation (CDG) are a group of metabolic diseases due to defects in protein and lipid glycosylation. We searched for the primary defect in 3 children from 2 families with a severe neurological phenotype, including profound developmental delay, intractable epilepsy, progressive microcephaly, severe hypotonia with elevated blood creatine kinase levels, and early fatal outcome. There was clinical evidence of a muscular dystrophy-dystroglycanopathy syndrome, supported by deficient O-mannosylation by muscle immunohistochemistry.
Methods:
Biochemical and molecular methods were combined to pinpoint the defect in the glycosylation pathway in the endoplasmic reticulum.
Results:
Metabolic investigations revealed CDG-I, pointing to a defect in protein N-glycosylation in the endoplasmic reticulum. Analysis of lipid-linked oligosaccharides in fibroblasts showed accumulation of Dol-PP-GlcNAc2-Man5. DNA analysis revealed mutations in DPM2, 1 of the subunits of the dolichol-phosphate-mannose (DPM) synthase; the patient in the first family is compound heterozygous for 2 mutations (c.68A>G, predicting a missense mutation p.Y23C and c.4-1G>C, a splice mutation), whereas the patients in the second family are homozygous for the same missense mutation (c.68A>G, p.Y23C).
Interpretation:
We describe a new CDG, due to a deficiency of DPM2. Hence, mutations have now been described in the genes for the 3 subunits of DPM: DPM1, DPM2, and DPM3, whereby DPM2-CDG links the congenital disorders of glycosylation to the congenital muscular dystrophies.


222) Oxidant-Dependent REDOX Responsiveness of Polysulfides

P.Carampin, E.Lallana, J.Laliturai, S.Carroccio, C.Puglisi, N.Tirelli

Macromolecular Chemistry and Physics  213,  2052-2061  - 2012

Poly(propylene sulfi de) (PPS) is studied as an oxidation-responsive macromolecular building block, in the perspective of anti-infl ammatory therapies. Here, we show that the nature of the oxidant has profound effects on the outcome of the oxidation process. PPS was exposed to hydrogen peroxide (H2O2) and hypochlorite (OCl-), which are oxidizing species commonly encountered during infl ammatory processes. It was found that the oxidation with H2O2 converted thioethers into sulfoxides, producing water-soluble macromolecular products with extremely low toxicity (L929 fi broblasts); on the contrary, the reaction with NaOCl produced sulfones in addition to sulfoxides, and this was accompanied by depolymerization, which appears to considerably affect the toxicity of the oxidation products.

Graphical Abstract



223) Glycomics of pediatric and adulthood diseases of the central nervous system

R.Barone , L.Sturiale, A.Palmigiano, M. Zappia, D.Garozzo

Journal of Proteomics  75,  5123-5139  - 2012

Glycosylation consists in the covalent linkage of a carbohydrate structure to membrane bound and secreted glycoconjugates. It is a common post-translational modification that serves multiple functions in cell differentiation, signaling and intercellular communication. Unlike DNA/RNA/protein, the addition of complex carbohydrates is not-template driven and it is conceivable that both genetics and environmental factors might interact to influence glycosylation machinery in several pathological processes. Over the last few decades, the recognition of Congenital Disorders of Glycosylation (CDG) as an increasing number of genetic diseases of glycosylation with almost constant nervous system involvement, dramatically illustrated the consequences of abnormal glycosylation as improper CNS development and function. In addition, CDG recognition contributed to postulate that aberrant glycosylation processes might play a role in multifactorial, complex CNS diseases. On this context, CNS glycomics explores the effects of possible aberrant glycosylation to identify potential glyco-biomarkers useful for the diagnosis and ultimately for potential intervention strategies in neurological diseases. Up to date, CNS glycomics is an emerging, still uncharted area because of the specificity of CNS glycosylation, the complexity of the neurological disorders and for the inaccessibility and invasiveness of disease relevant samples. Here we review current knowledge on clinical glycomics of nervous system diseases, starting with CDG to include those pediatric and adulthood neuropsychiatric diseases where some evidences suggest that multifactor determinants converge to dysregulate glycosylation. Conventional and mass spectrometrybased high throughput technology for glyco-biomarker detection in CNS diseases is reported.

graphical abstract



224) End-group rearrangements in poly(propylene sulfide) matrixassisted laser desorption/ionization time-of-flight analysis. Experimental evidence and possible mechanisms

E.Lallana, T.Ferreri, S.Carroccio, A.M.Puga, N.Tirelli

Rapid Communications in Mass Spectrometry  26,  2158-2164  - 2012

RATIONALE: Polysulfides [poly(1,2-alkylene sulfides)] are oxidation-responsive polymers that are finding application in drug release and biomaterials. The precise knowledge of their macromolecular characteristics is of the essence in view of their application to biological systems.
METHODS: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with and without silver trifluoroacetate was used to characterize a series of polymers with increasing molecular weight in the range 1000?4000 g/mol and with low polydispersity (<1.12).
RESULTS:Well-resolved peaks and accuratemass-measured values were obtained using a 2-(4-hydroxyphenylazo)benzoic acid (HABA) matrix, but significant fragmentations took place in the absence of silver as a cationizing reagent. Elimination reactions appeared to occur at terminal groups and limited depolymerization could be recorded. Interestingly, the most common fragmentation pathway seemed to be based on an as-yet-unreported process of hydrogen transfer requiring the presence both of ester groups and of thioethers.
CONCLUSIONS: The use of an appropriate cationizing reagent (silver trifluoroacetate) appeared to suppress end-group eliminations; we hypothesize that this action is based on the involvement of the terminal groups in silver chelation.


225) Investigation of bacterial resistance to the immune system response: Cepacian depolymerisation by reactive oxygen species

B.Cuzzi, P.Cescutti, L.Furlanis, C.Lagatolla, L.Sturiale, D.Garozzo, R.Rizzo

Innate Immunity  18(4),  661-671  - 2012

Reactive oxygen species (ROS) are part of the weapons used by the immune system to kill and degrade infecting microorganisms. Bacteria can produce macromolecules, such as polysaccharides, that are able to scavenge ROS. Species belonging to the Burkholderia cepacia complex are involved in serious lung infection in cystic fibrosis patients and produce a characteristic polysaccharide, cepacian. The interaction between ROS and bacterial polysaccharides was first investigated by killing experiments, where bacteria cells were incubated with sodium hypochlorite (NaClO) with and without prior incubation with cepacian. The results showed that the polysaccharide had a protective effect towards bacterial cells. Cepacian was then treated with different concentrations of NaClO and the course of reactions was followed by means of capillary viscometry. The degradation products were characterised by size-exclusion chromatography, NMR and mass spectrometry. The results showed that hypochlorite depolymerised cepacian, removed side chains and O-acetyl groups, but did not cleave the glycosidic bond between glucuronic acid and rhamnose. The structure of some oligomers produced by NaClO oxidation is reported.

Graphical Abstract



226) Structure of the lipopolysaccharide isolated from the novel species Uruburuella sius

A.Silipo, L.Sturiale, C.De Castro, R.Lanzetta , M.Parrilli, D.Garozzo, A.Molinaro

Carbohydrate Research  357 (2012),  75-82  - 2012

Uruburuella suis is a novel species isolated from lungs and heart of pigs with pneumonia and pericarditis. Phenotypic and phylogenetic evidences showed that it represented a hitherto unknown subline within the family Neisseriaceae. In the present work we defined the whole structure of the LPS isolated from Uruburuella suis. The structural determination, which was achieved by chemical, spectroscopic and spectrometric approaches, indicates a novel rough type lipopolysaccharide rich in negatively charged groups in the lipid A-inner core region. The elucidation of the structural features of the LPS from Uruburuella suis is a first step toward the comprehension of the characteristics of the cell envelope in such new and interesting microorganisms.

Graphical Abstract



227) Synthesis and characterization of charge-transporting ð-stacked polybenzofulvene derivatives

A.Cappelli, M.Paolino, G.Grisci, G.Giuliani, A.Donati, R.Mendichi, A.C.Boccia, C.Botta, W.Mroz, F.Samperi, A.Scamporrino, G.Giorgi, S.Vomero

Journal of Materials Chemistry  22,  9611-9623  - 2012

Two new benzofulvene derivatives bearing two or three methoxy substituents on the benzene ring were synthesized and induced to polymerize spontaneousl0y in order to investigate the photophysical and electronic properties of the corresponding polymers. The photophysical features of the newly synthesized polymers suggested a high degree of π-stacking both in the solid state and in diluted solutions, and the large Stokes shift was interpreted in terms of an efficient energy transfer within the excimer. Absorption and emission features in the solid state were found to be similar to those in diluted solutions and the stable PL quantum yield was considered a promising feature with regard to the potential applications of the polymers in light emitting devices. Finally, the remarkable hole mobility shown by poly-4,5,6-MO-BF3k along with the enhancing effect of the methoxy substituents in the charge mobility opens up new routes to the development of materials potentially useful in optoelectronics.



228) Structural Study of the Lipopolysaccharide O-Antigen Produced by the Emerging Cystic Fibrosis Pathogen Pandoraea pulmonicola

F.Di Lorenzo, A.Silipo, A.Costello, L.Sturiale, D.Garozzo, M.Callaghan, R.Lanzetta, M.Parrilli, S.McClean, A.Molinaro

European Journal of Organic Chemistry  2012(11),  2243-2249  - 2012

This is the first report on the molecular structure of the Ochain of the lipopolysaccharide produced by the emerging and highly virulent clinical isolate Pandoraea pulmonicola strain LMG 18108, an opportunistic human pathogen in cystic fibrosis patients. Monosaccharide analysis and 2D NMR spectroscopy revealed a novel polysaccharide, the structure of which consists of the trisaccharide repeating unit [→2-β-D-Quip3NAcyl-(1→4)-α-D-GalpNAc-(1→3)-α-D-GlcpNAc-1→]n. The quinovosamine residue was found to be linked by a very unusual acyl substituent, a five-membered-ring acyl residue, the 3-hydroxy-2,3-dimethyl-5-oxoprolyl group.



229) Combined Techniques for the Characterization of Polyfluorene Copolymers and Correlation with their Optical Properties

F.Samperi, S.Battiato, C.Puglisi, U.Giovanella, R.Mendichi, S.Destri

Macromolecules  45,  1811-1824  - 2012

New red- and green-emitting copolymers, hereafter core-copolymers, bearing a 4,7-bis(thiophen-2-yl)benzothiadiazole and a benzothiadiazole residue respectively as bridging core between two identical polymeric arms were synthesized by Suzuki coupling reaction of the dibromine derivative of such chromophores and essentially borolane-ended alternating copolymers [namely P(TPAF)] of triphenylammine disubstituted fluorene and dialkylsubstituted fluorene. All polymer samples were characterized by 1H NMR and in particular by MALDI-TOF MS. MALDI mass spectra allow the identification of many end groups of the initial blue-emitting macromers and therefore of the side reactions occurring during Suzuki polycondensation. The average molar masses were determined by two different SEC apparatus, one calibrated with conventional polystyrene narrow standards and the other with an absolute calibration curve built up by SEC/MALDI-TOF MS analysis of selected SEC fractions of polydisperse red and green core-copolymers. MALDI mass spectra of these fractions give reliable information on their composition, which combined with their integrated area calculated from the corresponding normalized SEC curves, enable the estimation, for the first time, of the percentage of macromolecules containing the dyes composing the neat core-copolymers. Optical characterization, performed by UV-visible absorption and photoluminescence measurements, of the same SEC fractions gives results in agreement with the different compositions determined by their MALDI mass spectra.>


230) Covalent nano-clip and nano-box compounds based on free base porphyrins

E.Scamporrino, P.Mineo, D.Vitalini

Tetrahedron  67(20),  3705-3713  - 2011

Novel nano-clip and nano-box compounds were obtained by reaction between dibromomethane and 5,15-di[ρ-(9-methoxytriethylenenoxy)phenyl]-10,20-di[ρ-hydroxyphenyl]porphyrin. The molecular architecture varies from a co-facial (nano-clip) to a four wall-box (nano-box) structure. The products were characterized by 1H NMR and UV-vis spectroscopy and MALDI-TOF mass spectrometric analysis. The UV-vis spectra of the nano-clip showed a modification of the characteristic porphyrin soret and Q bands, with respect to the monomer and cyclic tetramer, as a probable consequence of a hybrid orbital deformation (HOD) phenomenon involving the two porphyrin p rings forced to a closer co-facial spatial arrangement. The spatial distance between the two co-facial porphyrin units, and therefore the molecular cavity size, can be modified inducing an electrostatic repulsion by means of a reversible protonation of the pyrrolic cores. The 1H NMR spectra of the nano-box showed a strong high-field shift of some aromatic and ether protons present in the upper and lower rim of the molecular box.

graphical abstract



231) Synthesis, Characterization, and Properties of New Phosphorus-Containing Epoxy Resins

S.Failla, P.Finocchiaro, G.A.Consiglio, F.Samperi, S.Battiato, A.Scamporrino

Phosphorus, Sulfur, and Silicon and the Related Elements  186(11),  2189-2201  - 2011

Four new phosphonate-epoxy monomers were synthesized and characterized by 1H and 31P-NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) tools. Beside the expected compund, the formation of a small amounts of linear oligomers was also observed by MALDI-TOF MS. These monomers were used to prepare new phosphorus-containing epoxy resins in order to obtain potential flame retardant polymers. The thermal behavior of these new epoxy resin was studied by DSC, TGA, and direct pyrolysis mass spectrometry (DPMS). TGA and DPMS data show that either the maximum decomposition temperature (PDT) or the onset of the thermal degradation of the phosphorus-containing epoxy resins is lower than that of the corresponding nonphosphonate samples.



232) A Snapshot of Thermo-Oxidative Degradation Products in Poly(bisphenol A carbonate) by Electrospray Ionization Mass Spectrometry and Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry

S.Carroccio, P.Rizzarelli, D.Zampino

Macromolecular Chemistry and Physics  212(24),  2648-2666  - 2011

The products derived from thermo-oxidation of poly(bisphenol A carbonate) (PC) and their related degradation pathways are investigated. PC degradation is carried out at 300 °C in air. The oxidized products are analyzed for the fi rst time by using direct electrospray mass spectrometry (MS) and matrixassisted laser desorption ionization time of fl ight MS. Together with the formation of bisphenol A oligomers, several new structures containing biphenyl units, phenols, acetophenones, alcohols, acids, and xanthones molecules are detected. The use of thin fi lms, instead of PC bulk, allows one to obtain precise information about mechanisms involved during thermooxidative processes and to establish a new order of priorities among the renowned degradative reactions.


233) O-Acetyl location on Cepacian, the principal exopolysaccharide of Burkholderia cepacia complex bacteria

P.Cescutti, G.Impallomeni, D.Garozzo, R.Rizzo

Carbohydrate Research  346 (18),  2905-2912  - 2011

Cepacian is an exopolysaccharide produced by the majority of the isolates belonging to the Burkholderia cepacia complex bacteria, a group of 17 species, some of which infect cystic fibrosis patients, sometime with fatal outcome. The repeating unit of cepacian consists of a backbone having a trisaccharidic repeating unit with three side chains, as reported in the formula below. The exopolysaccharide is also acetylated, carrying from one to three acetyl esters per repeating unit, depending on the strain examined. The consequences of O-acetyl substitution in a polysaccharide are important both for its biological functions and for industrial applications, including the preparation of conjugated vaccines, since O-acetyl groups are important immunogenic determinants. The location of acetyl groups was achieved by NMR spectroscopy and ESI mass spectrometry and revealed that these substituents are scattered in non-stoichiometric ratio on many sugar residues in different positions, a feature which adds to the already unique carbohydrate structure of the polysaccharide.



234) Reflectron MALDI TOF and MALDI TOF/TOF mass spectrometry reveal novel structural details of native lipooligosaccharides

L.Sturiale, A.Palmigiano, A.Silipo, Y.A.Knirel, A.Anisimov, R.Lanzetta, M.Parrilli, A.Molinaro, D.Garozzo

Journal of Mass Spectrometry  46,  1135-1142  - 2011

Lipooligosaccharides (LOS) are powerful Gram-negative glycolipids that evade the immune system and invade host animal and vegetal cells. The structural elucidation of LOS is pivotal to understanding the mechanisms of infection at the molecular level. The amphiphilic nature of LOS has been the main obstacle for structural analysis by matrix-assisted laser desorption/ ionization (MALDI) mass spectrometry (MS). Our approach has resolved this important issue and has permitted us to obtain reflectron MALDI mass spectra of LOS to reveal the fine chemical structure with minimal structural variations. The high-quality MALDI mass spectra show LOS species characteristic of molecular ions and defined fragments due to decay in the ion source. The in-source decay yields B-type ions, which correspond to core oligosaccharide(s), and Y-type ions, which are related to lipid A unit(s). MALDI tandem time-of-flight (TOF/TOF) MS of lipid A allowed for the elucidation of its structure directly from purified intact LOS without the need for any chemical manipulations. These findings constitute a significant advancement in the analysis of such an important biomolecule by MALDI MS.


235) A click chemistry-based "grafting through" approach to the synthesis of a biorelevant polymer brush

A.Cappelli, M.Paolino, G.Grisci, G.Giuliani, A.Donati, R.Mendichi, A.C.Boccia, F.Samperi, S.Battiato, E.Paccagnini, E.Giacomello, V.Sorrentino, M.Licciardi, G.Giammona, S.Vomero

Polymer Chemistry  2,  2518  - 2011

A new biorelevant polymer brush showing a polybenzofulvene backbone was synthesized by a "grafting through" approach based on click chemistry and spontaneous polymerization reactions. The easy polymerization of the relatively complex monomer (6-MOEG-9-TM-BF3k) suggests the existence of a particularly efficient recognition process capable of pre-organizing the monomer molecules for the spontaneous polymerization. 13C-NMR spectroscopy as well as UV-vis and fluorescence spectroscopy suggested for poly-6-MOEG-9-TM-BF3k the features of a vinyl (1,2) π-stacked polymer. The new polybenzofulvene derivative was found to interact with water at room temperature to give clear water solutions, but TEM analysis demonstrated the presence of macromolecular aggregates showing dimensions larger than those suggested by SEC-MALS analysis for the isolated macromolecules. DLS studies confirmed the presence of objects showing average dimensions in the range of 200-300 nm and suggested thermoresponsive colloidal properties for poly-6-MOEG-9-TM-BF3k macromolecules. Finally, owing to its favourable absorption/emission properties and water solubility, the interaction of poly-6-MOEG-9-TM-BF3k with live cells was studied by fluorescence microscopy experiments, which revealed that the polymer brush was unable to enter live cells and alter cell morphology.


236) PVC silver zeolite composites with antimicrobial properties

D.Zampino, T.Ferreri, C.Puglisi, M.Mancuso, R.Zaccone, R.Scaffaro, D.Bennardo

Journal of materials science  46,  6734-6743  - 2011

Poly(vinyl chloride) (PVC) composites containing increasing amounts (2-20%, w/w) of silver zeolite (SZ) were prepared by melt mixing and characterized by thermal, mechanical and rheological analyses. The addition of large amount of SZ did not influence the processability and the formability of the composites, if compared to neat plasticized PVC. The antibacterial activity of PVC SZ composites was tested on Escherichia coli and Staphylococcus epidermidis and resulted promising both in culture broth and on agar plate and also in sterile urine seeded with these strains, for simulation purposes. In sterile urine, composites induced a significant reduction (4-6 log units) of viability of both strains already at 24 h, inhibiting E. coli growth up to 20 days, whereas their antimicrobial action against S. epidermidis vanished within 5 days. The silver release in sterile urine was determined up to 20 days. It was found that the highest amount of silver ions was released during the first day (0.365 ppm), whilst from days 6 to 20 the silver release decreased, reaching a steady daily mean value of 0.02 ppm.


237) The impact of mass spectrometry in the diagnosis of congenital disorders of glycosylation

L.Sturiale, R.Barone, D.Garozzo

Journal of Inherited Metabolic Disease  34(4),  891-899  - 2011

Contribution of mass spectrometry (MS) in the diagnosis and characterization of congenital disorders of glycosylation (CDG) has long been known. CDG type I diseases are characterized by the under-occupancy of protein N-glycosylation sites. Electrospray (ESI) MS and matrix assisted laser desorption ionization (MALDI) MS are effective for underglycosylation analyses of intact serum Transferrin (Tf) in CDG-I patients by mass determination of individual component glycoforms. Thus, highthroughput methods developed to speed-up analytical times found increasing application in clinical testing for CDG detection. ESI MS recognizable glycoform profiles of serum Tf have been reported in CDG-I different from PMM2-CDG and in individual CDG-II defects. MALDI MS analysis of acidic and neutral N-linked glycans released from total plasma or targeted glycoproteins, is the mainstream tool to explore abnormal oligosaccharide structure and changes in the relative amount of individual oligosaccharides in CDG-II patients. Here we briefly review stateof-the-art and updates of MS-based applications for the diagnosis of CDG with special emphasis to detectable glycosylation profiles reported in different CDG types.


238) Combined Techniques for the Characterization of Linear-Hyperbranched Hybrid Poly(Butylene Adipate) Copolymers

F.Samperi, S.Battiato, C.Puglisi, A.Scamporrino, V.Ambrogi, L.Ascione, C.Carfagna

Journal of Polymer Science part A: Polymer Chemistry  49,  3615-3630  - 2011

Linear-hyperbranched hybrid poly(butylene adipate) (HPBA) copolymers were synthesized through a branching reaction between the linear tailored prepolymer terminated with methyl ester groups and different mol percents of the 1,1,1-tris(hydroxymethyl) propane (TMP) as branching agent, using the titanium(IV) isopropoxide as catalyst, at 180 C under vacuum for different times. All samples were characterized by NMR and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). In particular, MALDI-TOF mass spectra of the unfractionated and size exclusion chromatography (SEC)-fractionated hyperbranched (HB) samples gave information on their composition, on the end groups as well as on the TMP units present in each family of HB macromolecules. HB chains containing cyclic branches and ether bonds formed by intermolecular transesterification and intramolecular and intermolecular transetherification side reactions, respectively, were also revealed by MALDI-TOF MS analysis. All samples were also investigated by SEC. The average molar masses (MMs) evaluated by SEC calibrated with the polystyrene (PS) narrow standards were overestimated with respect to those calculated by the SEC/MALDI-TOF MS selfcalibration method, which gave reliable values. Moreover, it also showed that the hydrodynamic volume of the HPBA polymers was higher than that of the linear PSs with similar MMs.


239) Synthesis and characterization of poly(3-hydroxyalkanoates) from Brassica carinata oil with high content of erucic acid and from very long chain fatty acids

G.Impallomeni, A.Ballistreri, G.M.Carnemolla, S.P.P.Guglielmino, M.S.Nicolo, M.G.Cambria

International Journal of Biological Macromolecules  48(1),  137-145  - 2011

Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when grown on substrates contg. very long chain fatty acids (VLCFA, C > 20). Looking for low cost carbon sources, we tested Brassica carinata oil (erucic acid content 35-48%) as an intact triglyceride contg. VLCFA. Oleic (C18:1), erucic (C22:1), and nervonic (C24:1) acids were also employed for mcl-PHA prodn. as model substrates. The polymers obtained were analyzed by GC of methanolyzed samples, GPC, 1H and 13C NMR, ESI MS of partially pyrolyzed samples, and DSC. The repeating units of such polymers were satd. and unsatd., with a higher content of the latter in the case of the PHA obtained from B. carinata oil. Statistical anal. of the ion intensity in the ESI mass spectra showed that the PHAs from pure fatty acids are random copolymers, while the PHA from B. carinata oil is either a pure polymer or a mixt. of polymers. Wt.-av. mol. wt. varied from ca. 56,000 g/mol for the PHA from B. carinata oil and oleic acid, to about 120,000 g/mol for those from erucic and nervonic acids. The PHAs from erucic and nervonic acids were partially cryst., with rubbery characteristics and a m.p. (Tm) of 50 °C, while the PHAs from oleic acid and from B. carinata oil afforded totally amorphous materials, with glass transition temps. (Tg) of -52 °C and -47 °C, respectively.


240) Synthesis and characterization of new copolyacrylates containing porphyrin units as pendant groups and their use as sensors

S.Dattilo, P.Mineo, E.Scamporrino, E.Spina, D.Vitalini

Journal of Polymer Science part A: Polymer Chemistry  49(3),  796-802  - 2011

Novel copolyacrylates contg. various molar ratios of 5,10,15-tri[p-(9-methoxy-triethylenoxy)phenyl]-20-(p-acryloxyphenyl)porphyrin units in the chains have been synthesized, and their chem. structure was detd. by NMR and MALDI-TOF mass spectrometry. Sensing response of the synthesized copolymers has been tested for trifluoroacetic and hydrochloric acids and nitrogen dioxide analytes. The reported sensing data indicate that porphyrin units are interacting with analytes in a reversible fashion.


241) Preparation, characterization and biodegradation of biopolymer nanocomposites based on fumed silica

K.Fukushima, D.Tabuani, C.Abbate, M.Arena, P.Rizzarelli

European Polymer Journal  47(2),  139-152  - 2011

PLA and PCL based nanocomposites prepared by adding three different types of fumed silica were obtained by melt blending. Materials were characterized by means of Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Dynamic-Mechanical Thermal Analysis (DMTA). A good distribution of the fumed silica into both polymer matrices was observed. The highest thermo-mechanical improvements were reached by addition of the fumed silica with higher surface area. PLA and its nanocomposites were degraded in compost at 58°C; at this temperature all samples presented a significant level of polymer degradation, but a certain protection action of silica towards PLA degradation was observed, whereas the addition of fumed silica did not show considerable influence on the degradation trend of PCL. These dissimilarities were attributed to the different degradation mechanism of the two polymers.


242) Direct Electrospray Ionization Mass Spectrometry Quantitative Analysis of Sebacic and Terephthalic Acids in Biodegradable Polymers

P.Rizzarelli, D.Zampino, L.Ferreri, G.Impallomeni

Analytical Chemistry  83,  654-660  - 2011

A direct, rapid, and easy electrospray ionization mass spectrometry (ESI-MS) method to determine concentrations of sebacic acid (SA) and terephthalic acid (TA) residues in biodegradable copolymers was developed. Copolyester samples were synthesized from 1,4-butanediol and sebacic and terephthalic acids by melt polymerization. Extraction of monomers was performed in methanol. Their concentrations were determined by direct infusion ESI-MS, without chromatographic separation, using 1,12-dodecanedioic acid (DDA) as an internal standard. Calibration curves were obtained by plotting the ratio of the areas of the peaks relative to monomers and DDA standard as a function of their concentration ratio. We validated the method by determining the concentration of TA residue using both the ESI-MS protocol and high-performance liquid chromatography (HPLC) analysis with UV detection. The linearity range and the detection limit of this assay were 0.1-5.0 and 0.01 ppm for SA and 0.1-6.0 and 0.03 ppm for TA. This assay represents a useful alternative to conventional methods currently employed for acid quantification, resulting advantageous for its speed and high sensitivity.


243) Clinical characterization of a novel congenital disorder of glycosylation (DPM2 mutation)

R.Barone, V.Race, L.Sturiale, R.Bammens, W.Vleugels, L.Keldermans, D.Garozzo, F.Foulquier, J.Jaeken, G.Sorge, A.Fiumara, G.Matthijs

Journal of Inherited Metabolic Disease  33,  S74  - 2010

Background:The human dolichol-phosphate-mannose (DPM) synthase is a heterotrimeric complex composed of DPM1, DPM2 and DPM3. Only mutations in DPM1 (the catalytic subunit) and more recently in DPM3 have been described.
Case Report: The girl was born to unrelated parents at the 32th week of gestation complicated by polyhydramnios. At birth she had normal growth parameters, severe hypotonia and dysmorphism. At six months, microcephaly (OFC: 33.5 cm), keel thorax,widely spaced nipples and joint flexion contractures were seen. Repeated laboratory investigations showed elevation of serum transaminases and CPK levels and coagulopathy. At age 20 months there were severe hypotonia, no head control, reduced active limb movements with normal osteotendineous reflexes. She experienced pharmacoresistant generalized tonic seizures and myoclonic jerks. Funduscopy showed optic atrophy. Brain MRI documented loss of cerebral white matter, without cerebellar atrophy. She died at age 36 months from pneumonia. Serum Transferrin (Tf) IEF showed overt increase of disialo-Tf and a very faint asialo-Tf band (type I pattern). PMM and PMI enzymes were normal. MALDI-MS of serum Tf showed di-glycosylated Tf and an additional glycoform owing to mono-glycosylated Tf. Unlike CDG-Ia (PMM deficiency), no a-glycosylated Tf species were detectable. Lipid-linked oligosaccharides analyses showed an accumulation of dol-PP-GlcNAc2-Man5. No mutations in DPM1, ALG3 or MPDU1 were detected. The patient was compound heterozygote for a splice mutation (c.4-1G>C) and a missense mutation (c.68A>G, p.Y23C) in the DPM2 gene.
Conclusions: Prominent neurological involvement, dysmorphism and fatal outcome were hallmark clinical features in the first CDG patient with DPM2 mutation.


244) Characterization of Copolyesteramides from Reactive Blending of PET and MXD6 in the Molten State

F.Samperi, M.S.Montaudo, S.Battiato, D.Carbone, C.Puglisi

Journal of Polymer Science: Part A: Polymer Chemistry  48,  5135-5155  - 2010

Poly(ethylene terephthalate)-poly(m-xylylene adipamide) PET-MXD6 copolymers were prepared by reactive blending of equimolar PET/MXD6 blends at 285 °C for different times in presence of terephthalic acid (1 wt %). First, the partial hydrolysis of PET and MXD6 occurs, yielding oligomers terminated with the reactive aromatic carboxyl groups. These oligomers quickly react with ester and amide inner groups producing a PET-MXD6 copolymer that may compatibilize the initial biphasic blend. In this homogeneous environment, the aliphatic carboxyl-terminated MXD6 chains, inactive in the initial biphasic blend, may promote the exchange reactions determining the formation of a random copolymer at longer reaction time (120 min). The progress of exchange reactions, and the microstructure of the formed copolyesteramides, versus the reaction time was followed by 1H and 13C NMR analyses using a CDCl3/TFA-d/(CF3CO)2O mixture as solvent and applying appropriate mathematical models. Dyads and triads sequences were thoroughly characterized by NMR. Semicrystalline block copolymers were obtained at reaction time lower than 45 min. All PET-MXD6 copolymers show a single Tg that change as a function of the dyads molar composition in the copolymers. The measured Tg values match with those calculated by a proposed modified Fox equation that take into account the weight fraction of the four dyad components of the PET-MXD6 copolymers.


245) Amino terminated copoly(ethersulphone)s bearing biphenylenic units in the backbone: Synthesis and characterization

A.Mamo, A.Aureliano, S.Battiato, G.Cicala, F.Samperi, A.Scamporrino, A.Recca

Polymer  51(14),  2972-2983  - 2010

The present project is based on the synthesis of new essentially amino-ended copoly(ether sulphone)s which are characterized by the presence of rigid biphenyl units in the main chain. All the compounds have been fully characterized by (1H and 13C) NMR, FTIR, and MALDI-TOF MS techniques. Complete assignments of the 1H and 13C NMR spectra have been accomplished by comparison with model compounds and literature data. The thermal properties of the copolymers were studied by differential scanning calorimetry (DSC). The glass transition temperature of the copolymers increases as increasing the molar composition of ethere sulphone units containing biphenyl moiety. The copolymers synthesized might find application as reactive toughening agents for multifunctional epoxy resins when high thermal properties are a requirement.


246) Synthesis and Characterization of Sulfonated Copolyethersulfones

F.Samperi, S.Battiato, C.Puglisi, V.Asarisi, A.Recca, G.Cicala, R.Mendichi

Journal of Polymer Science part A: Polymer Chemistry  48,  3010-3023  - 2010

The present article deals with the synthesis and characterization of some sulfonated copolyethersulfones. The synthetic approach differs from the post sulfonation approach traditionally reported in the literature. The synthetic procedure is based on the use of sulfonated monomers which are then reacted with previously synthesized telechelic hydoxy-ended poly (ether sulpnone)s. Combining the MALDI-TOF MS and 1H NMR analyses, with SEC-Viscometry and TGA measurements, we demonstrate a powerful tool for characterizing the chemical composition, end chains, degree of sulfonation (DS) and molecular mass distribution (MMD) of disulfonated poly(arylene ether-sulfone) copolymers. The characterization techniques allowed to determine the exact nature of the copolymers synthesized and to reveal some interesting features about the reaction. DMA data show that the glass transition temperature of sulfonated copolymers with similar DS increase as raise their MMD. Copolymers with a DS of 10-11 mol % reach a Tg of 244-246 °C.


247) New Amphiphilic Conjugates of Mono- and Bis(carboxy)-PEG2,000 Polymers with Lipoamino Acids as Surface Modifiers of Colloidal Drug Carriers

R.Pignatello, V.Pantò, L.Basile, G.Impallomeni, A.Ballistreri, V.Pistarà, E.F.Craparo, G.Puglisi

Macromolecular Chemistry and Physics  211,  1148-1156  - 2010

Linking PEG2,000 polymers ending in 1 or 2 carboxylic groups to lipoamino acids (LAAs) gives mono- and homo-disubstituted PEG-LAA conjugates. They show an identical solubility to parent PEGs in water and organic solvents. By DSC the degree and depth of interaction of these conjugates with a biomembrane model is studied, gaining information about their future incorporation in drug-loaded nanocarriers. The ability of PEG-LAA conjugates to adopt an ordinate arrangement on the surface of particles and efficiently cover them is demonstrated, compared to DSPE-PEG, by measuring the zeta potential values of negatively charged liposomes prepared in their presence.

formula



248) The structure of the carbohydrate backbone of the lipooligosaccharide from an alkaliphilic Halomonas sp.

A.Silipo, V.Gargiulo, L.Sturiale, R.Marchetti, P.Prizeman, W.D.Grant, C.De Castro, D.Garozzo, R.Lanzetta, M.Parrilli, A.Molinaro

Carbohydrate Research  345(13),  1971-1975  - 2010

The structure of the carbohydrate backbone of the core-lipid A region of the lipooligosaccharide (LOS) of the alkaliphilic and slightly halophilic bacterium Halomonas sp. has been elucidated. The LOS was fully deacylated, dephosphorylated, and reduced at the free reducing end. The structure, obtained by means of compositional analysis, 2D NMR spectroscopy, and MALDI mass spectrometry, was determined as the following:

All sugars are D-pyranoses; Hep is L-glycero-D-manno-heptose and Kdo is 3-deoxy-D-manno-oct- 2-ulosonic acid.


249) Structure-Property Relationships in Densely Grafted ð-Stacked Polymers

A.Cappelli, M.Paolino, P.Anzini, G.Giuliani, S.Valenti, M.Aggravi, A.Donati, R.Mendichi, L.Zetta, A.C.Boccia, F.Bertini, F.Samperi, S.Battiato, E.Paccagnini, S.Vomero

Journal of Polymer Science part A: Polymer Chemistry  48(11),  2446-2461  - 2010

Three methyl end-capped oligo(ethylene glycol) (MOEG) ethers (1b-d) and a methoxyderivative (1a) of benzofulvene monomer BF3k were synthesized and induced to polymerize spontaneously by solvent removal to obtain soluble π-stacked polymers bearing densely grafted MOEG side chains (poly-1b-d) and model polymer poly-1a. The physicochemical features (e.g., solubility, NMR, MALDI-TOF, and absorption/emission spectra, as well as MWD, conformation plot, and thermal properties) of the synthesized polymers were compared in a structure-property relationship study. This approach afforded the following evidence. The structure of poly-1a-d is very similar to that of BF3k, suggesting that the polymerization mechanism is not affected by the presence of the electron-rich methoxy group or bulkier MOEG side chains. However, the latter appear to be capable of affecting the conformational behavior of the polymer backbone. The solubility of poly-1a-d depends on the number of the oligo (ethylene glycol) monomeric units. In particular, poly-1d, featuring a long MOEGside chain (n = 9), shows an amphiphilic character and is soluble in a number of organic solvents, whereas it interacts with water to give isolated macromolecules in equilibrium with nanosized water-soluble aggregates.


250) Against the rules: A marine bacterium, Loktanella rosea, possesses a unique lipopolysaccharide

T.Ieranò, A.Silipo, E.L.Nazarenko, R.P.Gorshkova, E.P.Ivanova, D.Garozzo, L.Sturiale, R.Lanzetta, M.Parrilli, A.Molinaro

Glycobiology  20(5),  586-593  - 2010

Bacteria are an inimitable source of new glyco-structures potentially useful in medicinal and environmental chemistry. Lipopolysaccharides (LPS; endotoxins) are the major components of the outer membrane of Gram-negative bacteria; being exposed toward the external environment they can undergo structural changes and thus, they often possess peculiar chemical features that allow them to thrive in harsh chemical and physical environments. Marine bacteria have evolved and adapted over millions of years in order to succeed in different environments, finding a niche for their survival characterized by severe physical or chemical parameters. The present work focuses on the structural investigation of the LPS from Loktanella rosea, a marine Gram-negative bacterium. Through chemical analysis, 2D nuclear magnetic resonance and matrix-assisted laser desorption ionization mass spectrometry investigations, a unique LPS carbohydrate backbone has been defined. The lipid Askeleton consists of a trisaccharide backbone lacking the typical phosphate groups and is characterized by two β-glucosamines and an α-galacturonic acid. The core region is built up of three ulosonic acids, with two 3-deoxy-D-manno-oct-2-ulopyranosonic acid residues, one of which is carrying a neuraminic acid. This carbohydrate structure is an exceptional variation from the typical architectural skeleton of endotoxins which consequently implies a very different biosynthesis.


251) The structure of the carbohydrate backbone of the lipooligosaccharide from the halophilic bacterium Arcobacter halophilus

A.Silipo, L.Sturiale, V.Perino, D.Garozzo, R.Lanzetta,.M.Parrilli, A.Molinaro

Carbohydrate Research  345(6),  850-853  - 2010

A novel oligosaccharide was isolated and identified from the lipooligosaccharide fraction of the halophilic marine bacterium Arcobacter halophilus. The complete structure was achieved by chemical analysis, 2D NMR spectroscopy, and MALDI mass spectrometry as the following:

α-Glc-(1 → 7)-α-Hep-(1 → 5)-α-Kdo4P-(2 → 6)-β-GlcN4P-(1 → 6)-α-GlcN1P.



252) Biodegradation trend of poly(ε-caprolactone) and nanocomposites

K.Fukushima, C.Abbate, D.Tabuani, M.Gennari, P.Rizzarelli, G.Camino

Materials Science and Engineering C  30(4),  566-574  - 2010

PCL nanocomposites based on two organically modified montmorillonites at 5% clay loading were biodegraded in a mature compost. All samples showed an effective degradation in compost but nanoclays were found to partially delay the process. Biodegradation carried out by microorganisms isolated from the compost showed that the bacterium Bacillus licheniformis was able to degrade the studied systems without considerable differences in the polymer degradation trend due to the presence of nanoclays.


253) Structural Elucidation of a Novel B. cenocepacia ET-12 Lipooligosaccharide Isolated from a Cystic Fibrosis Patient after Lung Transplantation

T.Ieranò, A.Silipo, L.Sturiale, D.Garozzo, P.Corris, J.Perry, R.Lanzetta, M.Parrilli, A.De Soyza, A.Molinaro

European Journal of Organic Chemistry  2010(7),  1299-1306  - 2010

In this work, we carried out the elucidation of a novel lipooligosaccharide (LOS) from a clinical strain of the most virulent strain of the Burkholderia cepacia complex, which was of B. cenocepacia ET-12 epidemic strain lineage. The strain was isolated from a cystic fibrosis patient who had successfully undergone lung transplantation. This molecule presents some specific chemical differences when compared to the LOS reported so far from other B. cenocepacia ET-12 clones. The new endotoxin was also tested as a cytokine enhanceron human myelomonocytic U937 cells. Lipopolysaccharides are the main virulence factors of Gram-negative bacteria, and since they are exposed to the extracellular space, they are deeply involved in bacterial adaptation to the host environment. The characterisation of structural motifs present in these molecules is essential to the comprehension of the persistence/ survival mechanisms and inflammatory potential of these bacteria.


254) Densities, Viscosities, Refractive Indices, and Heat Capacities of Poly(ethylene glycol-ran-propylene glycol) + Esters of Carbonic Acid at (293.15 and 313.15) ° K and at Atmospheric Pressure

F.Comelli, A.Bigi, D.Vitalini, K.Rubini

Journal of Chemical & Engineering Data  55(1),  205-210  - 2010

Densities, ρ, dynamic viscosities, η, refractive indexes, nD, and heat capacities, Cp, for the binary mixts. contg. poly(ethylene glycol-ran-polypropylene glycol) + esters of carbonic acid were detd. at (293.15 and 313.15) K and at atm. pressure using an Anton Paar d. meter, a Schott-Gerate AVS viscometer, an Abbe refractometer, and a Perkin-Elmer differential scanning calorimeter. Vol. variations, ΔV, during mixing and deviations of the dynamic viscosities, Δη, were obtained at these temps. and are neg. for all mixts. Exptl. data were fitted to the Redlich-Kister equation, and the adjustable parameters and the std. deviations between exptl. and calcd. values were estd.


255) Secondary disorders of glycosylation in inborn errors of fructose metabolism

E.Quintana, L.Sturiale, R.Montero, F.Andrade, C.Fernandez, M.L.Couce, R.Barone, L.Aldamiz-Echevarria, A.Ribes, R.Artuch, P.Briones

Journal of Inherited metabolic disease  32 (Suppl 1),  S273-S278  - 2009

Adamowicz and colleagues raised the alert in 2007 about patients with atypical hereditary fructose intolerance (HFI) primarily misdiagnosed as CDG Ix. We describe a girl with neonatal hypertonia, facial trismus, absent swallowing and coughing reflexes, gastro-oesophageal reflux and sporadically elevated Krebs cycle metabolites and lactate. At 14 months microcephaly and hepatomegaly were noted, with hypertransaminasaemia but normal blood coagulation, glucose, phosphate, and absent urinary reducing substances. Neurological impairment persisted. Because of hepatic and neurological abnormalities with developmental delay, Tf IEF was performed and showed a severe type 1 pattern, resulting in a wrong diagnosis of CDG. Subsequently, an aversion to fruits suggested HFI, confirmed by the finding of ALDOB mutations (p.A150P-p.N335K). The girl improved with fructose-free diet, but liver cirrhosis led to hepatic transplantation. She is now 7 years old with good evolution; facial trismus and hypertonia reversed, but microcephaly persists. Transferrin MALDI-TOF MS characterization revealed underoccupation of glycosylation sites and glycan abnormalities, which reversed with dietary treatment. High maternal fructose concentrations might have caused neonatal abnormalities. Although in our patient_s mother there is no fructose accumulation at present, it is possible that increased ingestion of fruits and vegetables during pregnancy, together with her heterozygosity, caused an accumulation of fructose that finally affected the fetus. We also describe slightly abnormal transferrin isoelectric focusing and MALDI-TOF MS patterns of intact transferrin and N-glycans in a fructose-1,6-bisphosphatase (FBP1)-deficient patient. While HFI is a well-known cause of secondary CDG, we found no reports of abnormal transferrin isoelectric focusing patterns in FBP1 deficiency and we introduce this condition as a possible secondary cause for altered transferrin isoelectric focusing.


256) Clinical, Biochemical and Molecular studies of two siblings with CDG-Ix in the context of the first program for congenital disorders of glycosylation studies in Argentina

M.B.Bistué Millón, M.A.Delgado, N.B.Azar, N.Guelbert, L.Sturiale, G.Matthijs, J.Jaeken, R. Dodelson de Kremer, C.G.Asteggiano

Molecular Genetics and Metabolism  98 (1-2),  138-139  - 2009

Congenital Disorders of Glycosylation (CDG) are a rapidly growing family of diseases caused by defects in the biosynthesis of glycans attached to proteins and lipids. They have mostly a multisystem presentation, and have to be differentiated from protein variants and secondary CDG such as untreated classic galactosemia. Aim: To report the clinical, biochemical and molecular aspects of two siblings with unexplained CDG, in the context of the first CDG program in Argentina. Case report: We present two siblings born as the first and the third children of healthy Argentinean parents. One of them (a girl) had an early death (at the age of 4 months) and the other is now a 10 y-old girl. She showed liver dysfunction in the neonatal period, and has psychomotor retardation, hypotonia, microcephaly, seizures, feedings difficulties and hepatomegaly. She also developed strabismus and cataract. Methods: A) Analysis of serum N-glycoproteins using different assays: (1) Western blot (Wb), isoelectric focusing (IEF) and high performance liquid chromatography of transferrin (HPLC-Tf); (2) Enzymatic analysis of phosphomannomutase and phosphomannose isomerase activities in leucocytes; B) Lipid-linked oligosaccharide (LLO) analysis in fibroblasts, and D) Mass spectrometry (MS). Results: CDG-I was diagnosed based on the type 1 pattern of serum transferrin isoforms. CDG-Ia and CDG-Ib were excluded by enzymatic analysis. Secondary protein variants (polymorphisms) and other pathologies (galactosemia, fructosemia and alcohol abuse), were also excluded. LLO analysis showed no abnormal accumulation of intermediate precursors of the known forms of CDG-I. CDG-Ij and CDG-Ik were excluded by molecular analysis of ALG7 and ALG1 genes respectively. Discussion: We describe two siblings with a severe form of CDG-Ix. Studies are in progress to identify their basic defect. This CDG program allowed us to start a new genetic and metabolic chapter in our country and Latin America.


257) Densities, Viscosities, Refractive Indices, and Heat Capacities of Four Poly(ethylene glycol)-Poly(propylene glycol)-Poly(ethylene glycol)-block-Copolymers + Dimethyl Sulfoxide at (298.15 and 313.15) K and at Atmospheric Pressure

R.Francesconi, A.Bigi, D.Vitalini, K.Rubini, F.Comelli

Journal of Chemical & Engineering Data  54(3),  956-961  - 2009

Densities, ρ, dynamic viscosities, η, refractive indexes, nD, and heat capacities, Cp, for the binary mixts. contg. four block-copolymers [poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol)] (Mn = 1100, Mn = 1900, Mn = 2000, and Mn = 2800) + DMSO were detd. at (298.15 and 313.15) K and at atm. pressure using an Anton Paar densimeter, a Schott-Gerate AVS viscometer, an Abbe refractometer, and a Perkin-Elmer differential scanning calorimeter. Vol. variations, ΔV, during mixing and deviations of the dynamic viscosities, Δη, were obtained at these temps. and are neg. for all mixts. Exptl. data were fitted to the Redlich-Kister equation, and the adjustable parameters and the std. deviations between exptl. and calcd. values were estd.


258) Polyethersulfone-epoxy terminated materials as thermosetting resins for microelectronic devices

E.Scamporrino, P.Mineo, A.Scamporrino, S.Dattilo, D.Vitalini, R.Alicata

Journal of Polymer Science part A: Polymer Chemistry  47(21),  5682-5689  - 2009

A totally arom. polyether/sulfone resin (PES-E) was synthesized and tested as an insulating glue in the construction of a Chip-on-Chip (CoC) device. PES-E, essentially constituted of open-chain macromols. of low mol. mass (Mn of about 3000 Da) with hydroxy and/or epoxy end-groups, has a glass transition temp. of about 150° and is subject to crosslinking at temps. higher than 320°. A CoC device was assembled using a five-step process by interposing a layer of PES-E between two chips. After curing, SEM cross section images showed a homogeneous crosslinked resin layer well stuck (flick and shear tests) to both chips. The chem. structure of the chains and the hydroxy/epoxy end-groups ratio were optimized to obtain a crosslinked material with good adhesion and sufficient flexibility to avoid cracking during assembly and use.


259) Synthesis and characterization of poly(4-oxyalkylenoxy benzoate)s of different chain length

V.Siracusa, N.Lotti, C.Puglisi, F.Samperi, A.Munari, L.Finelli, S.Battiato

E-Polymers  9,  761-775  - 2009

Three different monomers starting from p-(4-hydroxy)benzoic acid and 3-chloro-1-propanol, 4-chloro-1-butanol and 6-chloro-1-hexanol, respectively, were synthesized and extensively characterized by means of 1H and 13C NMR, MALDI-TOF MS and elemental analysis. Subsequently, poly(4-oxyalkylenoxy benzoate)s polymers with different chain length were prepared in bulk starting from the mentioned above monomers, employing Ti(OBu)4 as catalyst, according to the usual two-stage polymerization procedure. The polymers were characterized in terms of chemical structure, molecular mass and thermal behaviour. Tg, Tm and the ability to crystallize were found to be affected by the number of methylene groups per repeat unit and the results were explained mainly on the basis of the increment of the chain flexibility.


260) Reactions Occurring during the Melt Mixing of Nylon 6 and Oxazoline- Cyclophosphazene Units

F.Samperi, S.Bazzano, S.Battiato, R.Scaffaro, L.Botta, M.C.Mistretta, R.Bertani, R.Milani

Macromolecules  42,  5579-5592  - 2009

Specific reactions of amino and carboxyl end groups of Nylon 6 with the reactive oxazoline groups belonging to a cyclophosphazene compound (referred as CP2OXA) were carried out at 240° C for different times, under inert atmosphere. Ny6 polymers terminated with one specific reactive chain end (-COOH or NH2) were reacted with different amounts of CP2OXA to study the kinetic order of the reactions. All Ny6-CP2OXA reacted products soluble in trifluoroethanol (TFE) were well characterized by MALDI-TOF MS, FT-IR and (1H and 13C) NMR techniques. The MALDI-TOF results show that the oxazoline rings react with the carboxyl chain ends of Ny6 following second-order kinetics. The reactions with amino chain ends are very fast and high amounts of gels are produced in just 5 min heating, whereas traces of gel are formed when Ny6COOH and CP-2OXA are reacted for 60 min. The gels were characterized by FTIR analyses, and also by MALDI-TOF MS after partial acid hydrolysis. MALDI-TOF mass spectra reveal also that oxazoline rings can react with -NHamide groups along the Ny6 chains, and with secondary amino groups formed by a condensation reaction involving the elimination of ammonia from two amino chain ends. These side reactions could be responsible of the formation of the gels. The polymerization of CP2OXA was also observed, and the oligomers formed could also react with Ny6 samples during the melt mixing.


261) Thermo-oxidative processes in biodegradable poly(butylene succinate)

P.Rizzarelli, S.Carroccio

Polymer Degradation and Stability  94,  1825-1838  - 2009

Aliphatic polyesters have acquired significant interest as environmentally friendly thermoplastics for a wide range of applications, and understanding their degradation behaviour has relevance both for processing and end uses. We have investigated the thermal and thermo-oxidative degradation processes occurring in synthetic and commercial poly(butylene succinate) (PBSu). Thermal oxidation was performed in atmospheric air using extremely thin polymer films at 170° C for up to 6 h. The oxidized compounds were analyzed by size exclusion chromatography (SEC), NMR spectroscopy, and Mass Spectrometry (MALDI-TOF MS). A measurable reduction of the molar mass of the polyesters was soon apparent, promoting the formation of PBSu oligomers with different end groups. MALDI mass spectrometry combined with the use of extremely thin polyester films provided a virtual magnifying glass to obtain exhaustive information on the structure of the oxidation products. An a-H abstraction mechanism has been unambiguously ascertained to be the primary step in PBSu oxidation. The oxidized polymer chains originating from the decomposition of the hydroperoxide intermediate by radical rearrangement reactions had not been revealed before. The latter products subsequently undergo chain scission processes, which can be accurately traced from the chemical species identified in our work. Thermal degradation experiments were also performed under nitrogen at 240-260° C. The new species identified in the MALDI spectra support a decomposition pathway taking place through a β-hydrogen-transfer mechanism, followed by the production of succinic anhydride from succinic acid end molecules via a back-biting process.


262) β-Amyloid Monomers Are Neuroprotective

M.L.Giuffrida, F.Caraci, B.Pignataro, S.Cataldo, P.De Bona, V.Bruno, G.Molinaro, G.Pappalardo, A.Messina, A.Palmigiano, D.Garozzo, F.Nicoletti, E.Rizzarelli, A.Copani

Journal of Neuroscience  29(34),  10582-10587  - 2009

The 42-aa-long β-amyloid protein--Aβ1-42--is thought to play a central role in the pathogenesis of Alzheimer’s disease (AD) (Walsh and Selkoe, 2007). Data from AD brain (Shankar et al., 2008), transgenic APP (amyloid precursor protein)-overexpressing mice (Lesné et al., 2006), and neuronal cultures treated with synthetic Aβ peptides (Lambert et al., 1998) indicate that self-association of Aβ1-42 monomers into soluble oligomers is required for neurotoxicity. The function of monomeric Aβ1-42 is unknown. The evidence that Aβ1-42 is present in the brain and CSF of normal individuals suggests that the peptide is physiologically active (Shoji, 2002). Here we show that synthetic Aβ1-42 monomers support the survival of developing neurons under conditions of trophic deprivation and protect mature neurons against excitotoxic death, a process that contributes to the overall neurodegeneration associated with AD. The neuroprotective action of Aβ1-42 monomers was mediated by the activation of the PI-3-K (phosphatidylinositol-3-kinase) pathway, and involved the stimulation of IGF-1 (insulin-like growth factor-1) receptors and/or other receptors of the insulin superfamily. Interestingly, monomers of Aβ1-42 carrying the Arctic mutation (E22G) associated with familiar AD (Nilsberth et al., 2001) were not neuroprotective. We suggest that pathological aggregation of Aβ1-42 may also cause neurodegeneration by depriving neurons of the protective activity of Aβ1-42 monomers. This "loss-of-function" hypothesis of neuronal death should be taken into consideration when designing therapies aimed at reducing Aβ burden.


263) First structural characterization of Burkholderia vietnamiensis lipooligosaccharide from cystic fibrosis-associated lung transplantation strains

T.Ieranò, A.Silipo, L.Sturiale, D.Garozzo, C.Bryant, R.Lanzetta, M.Parrilli, C.Aldridge, F.K.Gould, P.A.Corris, C.M.Anjam Khan, A.De Soyza, A.Molinaro

Glycobiology  19,  1214-1223  - 2009

This is the first structural elucidation of the lipooligosaccharide (LOS) endotoxin isolated from Burkholderia vietnamiensis, a clinically important member of Burkholderia cepacia complex, a group of over 10 opportunistic species that are highly problematic in cystic fibrosis.We have characterized a novel LOS structure extracted from two clonal strains of B. vietnamiensis isolated from a cystic fibrosis patient who underwent lung transplantation. Strains were selected from the pretransplantation and post-transplantation periods and endotoxin was extracted. Subsequent analysis interestingly revealed identical oligosaccharidic sequences, but variation in lipid A moieties. Further, both LOS fractions were tested for their immunostimulatory activity on human myelomonocytic U937 cells and for signaling on an HEK293 cell line stably expressing both TLR 4 and MD-2. We observed an increase in lipid A acylation and a resultant increase in biological activity in bio-reporter assays of TNF-α secretion in the post-transplantation strain.


264) A new mutation in COG7 extends the spectrum of COG subunit deficiencies

R.Zeevaert, F.Foulquier, D.Cheillan, I.Cloix, N.Guffon, L.Sturiale, D.Garozzo, G.Matthijs, J.Jaeken

European Journal of Medical Genetics  52,  303-305  - 2009

We describe a patient homozygous for a novel mutation in COG7, coding for one of the subunits of the Conserved Oligomeric Golgi complex, involved in retrograde vesicular trafficking. His brother showed a similar clinical syndrome and glycosylation defect but no DNA could be obtained from this patient. This mutation, c.170-7A > G, activates a cryptic splice acceptor and leads to the insertion of 2 amino acids at protein level (p.56-57insAT). The insertion disturbs the structure and function of the Conserved Oligomeric Golgi complex. In comparison to the previously described patients with a different COG7 mutation, intrauterine growth retardation and dysmorphic features were absent and there was a longer survival.


265) Poly(3-hydroxybutyrate-co-å-caprolactone) copolymers and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-å-caprolactone) terpolymers as novel materials for colloidal drug delivery systems

R.Pignatello, T.Musumeci, G.Impallomeni, G.M.Carnemolla, G.Puglisi, A.Ballistreri

European Journal of Pharmaceutical Sciences   37,  451-462  - 2009

Poly(3-hydroxybutyrate-co-ε-caprolactone) copolymers and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-ε-caprolactone) terpolymers were used by a solvent deposition technique to prepare either micro- or nanoparticles. In particular, the synthesis and analytical characterization of the terpolymers were described. On the basis of copolymer composition and properties, either micro- or nanoparticles were obtained; nanoparticle size was below 500 nm for the suspensions obtained from P(HB-co-CL) copolymers, and even smaller (200-300 nm) for those obtained using terpolymers. Particle size showed only a limited tendency to increase during storage, suggesting a good chemical and physical stability in the short-term storage at room temperature. Some copolymers produced hetero-dispersed microparticles under the same conditions, with a mean size between 10 and 30 μm. These systems showed a tendency to aggregate upon storage at room temperature. The nanoparticles showed a negative surface charge (around −20 mV for those prepared using an UltraTurrax and about −5 mV for those prepared by magnetic stirring). After storage at 4 °C the surface charge tend to decrease and these changes have been explained in terms of a partial hydrolysis of the polymeric matrix in aqueous suspension, which led to a change of chemical composition at the surface of the particles. The fluorescent probes calcein and Oil Red O were encapsulated in these systems as models of a hydrophilic and lipophilic drug molecule, respectively. Encapsulation efficiency and in vitro release profiles were studied to evaluate the effect of copolymer properties, such as molecular weight and composition, on their behaviour as potential materials to prepare controlled drug delivery carriers. Calcein was generally better encapsulated (up to 100%) than Oil Red O (10-30%); however, the ζ-potential measurement and in vitro release experiments suggested that a large amount of calcein was adsorbed onto the particle surface and was rapidly released within the first minutes of the test. Conversely, the lipophilic probe was dispersed within the polymeric matrix and its release profile from the nanoparticles was characterized by a considerable lag time (up to 8 h), followed by a slow and almost linear release. As a general trend, we observed that the composition and crystallinity of the tested polymers affected the type and size of obtained systems (micro- or nanoparticles), whereas the molecular weight mainly influenced the probes encapsulation and release.


266) Effect on Structural Relaxation of the Poly(methyl-methacrylate) Copolymers Chain Flexibility

S.Della Sciucca, G.Spagnoli, M.Penco, S.Battiato, F.Samperi, R.Mendichi

Journal of Polymer Science part B-Polymer Physics   47(6),  596-607  - 2009

The structural relaxation of poly(methyl-methaerylate) (PMMA)-based copolymers with different chain flexibility has been studied by DSC with the classical procedure of the isothermal and dynamical approach. Modified PMMA with different chain flexibility have been prepared by free radical polymerization in solution using a mixture of monomers containing 10 mol % of alkyl methacrylate (i.e., ethyl, buthyl, and hexyl methacrylate). The molecular characteristics of all the prepared copolymers have been performed by a multiangle laser light scattering (MALS) photometer on-line to a size exclusion chromatography (SEC) system (SEC-MALS) after and before the thermal treatments, NMR (H-1 and C-13) and MALDI-TOF mass spectrometry. A comparison of the apparent relaxation rate (R-H) was appraised from the enthalpy loss by annealing the different samples at the same level of undercooling (T-a = T-g - 18 degrees C). It was found an increase of R-H increasing the chain flexibility in the copolymers. Dynamical tests, performed at different cooling rates, have been used to estimate the apparent activation energy of the relaxation process.


267) Mass spectrometry in the characterization of human genetic N-glycosylation defects

R.Barone, L.Sturiale, D.Garozzo

Mass Spectrometry Reviews  28(3),  517-542  - 2009

Human genetic diseases that affect N-glycosylation result from the defective synthesis of the N-linked sugar moiety (glycan) of glycoproteins. The role of glycans for proper protein folding and biological functions is illustrated in the variety and severity of clinical manifestations shared by congenital disorders of glycosylation (CDG). This family of inherited metabolic disorders includes defects in the assembly of the oligosaccharide precursor that lead to an under-occupancy of N-glycosylation sites (CDG-I), and defects of glycan remodeling (CDG-II). Mass spectrometry constitutes a key tool for characterization of CDG-I defects by mass resolution of native protein glycoforms that differ for glycosylation-site occupancy. Glycan MS analyses in CDG-II is mandatory to detect whenever possible a repertoire of structures to pinpoint candidate enzymes and genes responsible for the abnormal N-glycan synthesis. In this manuscript, we review the MS applications in the area of CDG and related disorders with a special emphasis on those techniques that have been already applied or might become functional for diagnosis, characterization, and treatment monitoring in some specific conditions.


268) Chemically modified tetranitro-oxacalix[4]arenes: synthesis and conformational preferences of tetra-N-(1-octyl)ureido-oxacalix[4]arenes

C.Capici, D.Garozzo, G.Gattuso, A.Messina, A.Notti, M.F.Parisi, I.Pisagattia, S.Pappalardo

ARKIVOC  VIII,  199-211  - 2009

Tetranitro-oxacalix[4]arenes 1–5, prepared by direct SNAr reaction of 1,5-difluoro-2,4-dinitrobenzene with the appropriate aromatic diol (pyrocatechol, resorcinol, hydroquinone, 2,7-dihydroxynaphthalene, and 4,4´-dihydroxybiphenyl), were subjected to Raney-nickel reduction to provide the corresponding tetraamino-oxacalix[4]arenes 6–10, which upon treatment with an excess of 1-octyl isocyanate were converted into the title compounds 11–15, featuring a pair of 1,3-bis-[N-(1-octyl)ureido]phenylene moieties doubly connected at their 4,6-positions by rigid spacers of varied geometry. All new oxacalix[4]arenes were characterized by MALDI-TOF spectrometry and NMR spectroscopy. 1H NMR data and ab initio calculations support saddle-shaped conformations for oxacalix[4]arenes incorporating pyrocatechol, resorcinol and 2,7-dihydroxynaphthalene nucleophilic components, and boat-shaped conformations for derivatives possessing hydroquinone and 4,4´-dihydroxybiphenyl spacers.


269) Synthesis and Spontaneous Polymerization of Oligo(ethylene glycol)-Conjugated Benzofulvene Macromonomers. A Polymer Brush Forming a Physical Hydrogel

A.Cappelli, S.Galeazzi, G.Giuliani, M.Anzini, M.Grassi, R.Lapasin, G.Grassi, R.Farra, B.Dapas, M.Aggravi, A.Donati,L.Zetta, A.C.Boccia, F.Bertini, F.Samperi, S.Vomero

Macromolecules  42(7),  2368-2378  - 2009

Two methyl end-capped oligo(ethylene glycol) esters (1a,b) of benzofulvene derivative BF1 were synthesized and induced to polymerize spontaneously by solvent removal to give poly-1a,b showing both NMR and absorption/emission spectra very similar to those of poly-BF1. Poly-1a,b showed relatively high molecular weight and the tendency to depolymerize to a different degree as a function of the temperature in the presence of solvents, while they exhibited appreciable stability in the absence of solvent. Poly-1b, bearing a longer oligo(ethylene glycol) side chain, featured an amphiphilic character and interacted with a number of organic solvents to produce transparent gel aggregates, and with water to give a quite compact physical gel. Rheological studies performed on the hydrogel suggested strong gel characteristics and the combination of rheology and NMR transverse relaxation measurements allowed the pore size distribution in the hydrogel to be defined. Finally, biological studies performed with poly-1b solutions showed neither cytotoxicity nor cell viability impairment suggesting potential biocompatibility features for this polymer. In conclusion, poly-1b can be considered a promising polymer for the preparation of hydrogels potentially useful in a range of biological and biotechnological applications such as drug delivery, molecular recognition, biosensing, protein and DNA separation, micro- and nanofluidics, as well as tissue engineering.


270) Aliphatic hydrocarbons in metasomatized gabbroic xenoliths from Hyblean diatremes (Sicily): Genesis in a serpentinite hydrothermal system

E.Ciliberto, C.Crisafulli, F.C.Manuella, F.Samperi, S.Scirè, V.Scribano, M.Viccaro, E.Viscuso

Chemical Geology  258,  258-268  - 2009

Many tholeiite gabbro xenoliths from the Hyblean tuff-breccia deposits (Sicily, southern Italy) present mineralogical and geochemical evidence for hydrothermal alteration at different temperatures and water/ rock ratios. In some cases, the primary mineral assemblage has been entirely replaced by Na-rich alkali feldspar, chlorite/smectite interlayers, zeolites, aegirine–augite, titanite, zircon etc. Hence the chemical composition of such metasomatic rocks displays larger amounts of volatiles, alkalis, Zr, Hf, U, Th and lower Ca, Mg, Fe with respect to the original gabbro. Five hydrothermally altered gabbroic xenoliths were selected for thermal decrepitation and bulk gas analyses by quadrupole mass spectrometry. All the samples analyzed display the same Electron Impact-Direct Pyrolysis Mass spectra (EI-DPMS). These show a series of peaks differing by 14 mass units due to loss of methylene groups (–CH2), by a fragmentation process typical of saturated aliphatic and aliphatic–aromatic hydrocarbons. In addition, Fourier Transform Infrared (FT-IR) spectra of the samples present several bands typical of vibration frequencies of aliphatic hydrocarbons. The high-molecular-weight hydrocarbons observed probably originated from Fischer–Tropsch-type (FT-t) synthesis in the high temperature section of a serpentinite-hosted hydrothermal system. This suggestion may lend support to the recent hypothesis regarding the original oceanic nature of the Hyblean lithospheric basement.


271) AG-composites with antimicrobial properties

D.Zampino, T.Ferreri, C.Puglisi, M.Mancuso, R.Zaccone, R.Scaffaro

AIP Conference Proceedings  1042,  240  - 2008

DOI: https://doi.org/10.1063/1.2989018
Polymer composites with antimicrobial properties were prepared by mixing plasticised poly(vinyl chloride) (PVC) pellets with silver nanoparticles and silver zeolite in the amount of 8 wt% and 10 wt%, respectively. Thermal and mechanical properties of PVC composites were obtained by tensile and calorimetric (TGA and DSC) measurements. Rheological characterization was also performed by a parallel plates rheometer. The results indicate that the thermal and mechanical properties of PVC composites were not affected by the presence of both silver additives, with respect to the pure plasticised PVC. The antibacterial activity of PVC composites was examined on Escherichia coli and Staphylococcus epidermidis in Trypticase Soy Broth and in Trypticase Soy Agar for the direct inhibition. PVC composite with Ag-zeolite exhibited antibacterial activity against S. epidermidis and E. coli in culture broth and direct inhibition in agar plate (inhibition zone: 2-4 mm), for more than 7 days. PVC composites containing silver nanoparticles showed very low antimicrobial activity.


272) Long-standing mild hypertransaminasaemia caused by congenital disorder of glycosylation (CDG) type IIx

P.L.Calvo, S.Pagliardini, M.Baldi, A.Pucci, L.Sturiale, D.Garozzo, T.Vinciguerra, C.Barbera, J.Jaeken

Journal of inherited metabolic disease  31 (Suppl 2),  S437-S440  - 2008

A 32 year-old asymptomatic male came to our attention with a 21-year history, documented elsewhere, of puzzling increases in his serum transaminase level. At first, very low serum ceruloplasmin level suggested Wilson disease. Two liver biopsies showed mild portal inflammation, steatosis and mild fibrosis. Further investigation revealed low levels of the glycoproteins AT III and clotting factor XI, leading to a diagnosis of congenital disorder of glycosylation (CDG) type II. Further studies as to the cause of this "apparently new" CDG, are ongoing. On the basis of our data and a literature review, we suggest that subjects with asymptomatic hypertransaminasaemia be screened for CDG


273) A review on aromatic poly(ester-carbonate)s and transesterification resistant polyesters

M.S.Montaudo

E-Polymers  8,  581-587  - 2008

The review discusses poly(ester-carbonate)s (PECAs for brief), their production, characterization and their use. Great emphasis is on their production via ester-carbonate exchange and in particular on the copolymer obtained when mixing and heating poly(butylene terephthalate) (PBT for brief) or poly(ethylene terephthalate) (PET for brief) together with poly(bisphenol A carbonate) (PC for brief). Some notes are added on PECAs with long polyester and /or long polycarbonate blocks and for the case of "transesterification resistant" polymers i.e. when the production of random copolymers via ester-carbonate exchange is impossible under ordinary conditions.


274) The structure and proinflammatory activity of the lipopolysaccharide from Burkholderia multivorans and the differences between clonal strains colonizing pre and posttransplanted lungs

T.Ieranò, A.Silipo, L.Sturiale, D.Garozzo, H.Brookes, C.M.Anjam Khan, C.Bryant, F.K.Gould, P.A.Corris, R.Lanzetta, M.Parrilli, A.De Soyza, A.Molinaro

Glycobiology  18(11),  871-881  - 2008

The Burkholderia cepacia complex is a group of Gramnegative bacteria that are opportunistic pathogens for humans especially in cystic fibrosis patients. Lipopolysaccharide (LPS) molecules are potent virulence factors of Gram-negative bacteria organisms essential for bacterial survival. A complete analysis of the bacterial lipopolysaccharide structure to function relationship is required to understand the chemical basis of the inflammatory process. We have therefore investigated the structures of lipopolysaccharides from clonally identical Burkholderia multivorans strains (genomovar II) isolated pre- and post-lung transplantation through compositional analysis, mass spectrometry, and 2D NMR spectroscopy. We tested the LPS proinflammatory activity as a stimulant of human myelomonocytic U937 cell cytokine induction and assessed TLR4/MD2 signaling. Marked changes between the paired strains were found in the lipid A-inner core region. Such structural variations can contribute to the bacterial survival and persistence of infections despite the loss of a CF milieu following lung transplantation.


275) Synthesis, Characterization, and Nucleotidic Chain Cleavage Ability of Uncharged Water Soluble Poly(ethylene glycol)-Fullerene Derivatives with an Amphiphilic Character

D.Vitalini, E.Spina, S.Dattilo, P.Mineo, E.Scamporrino

Journal of Polymer Science part A: Polymer Chemistry  46,  2145-2153  - 2008

Water-soluble fullerenes containing two poly(ethylene glycol) branches [Full-(PEG)2] were prepared starting from commercial poly(ethylene glycol)-monomethyl ethers and C60 [Full-(PEG)2]s chemical characterization was made by FT-IR, NMR, and MALDI-TOF mass spectrometric analyses. Their thermal stability was determined by TGA experiments. The capability of C60-derivatives to induce oligonucleotide cleavage under visible light irradiation was also ascertained.


276) Macromolecular properties of cepacian in water and in dimethylsulfoxide

Y.Herasimenka, P.Cescutti, C.E.Sampaio Noguera, J.R.Ruggiero, R.Urbani, G.Impallomeni, F.Zanetti, S.Campidelli, M.Prato, R.Rizzo

Carbohydrate Research   343(1),  81-89  - 2008

Cepacian is the exopolysaccharide produced by the majority of the so far investigated clin. strains of the Burkholderia cepacia complex. This is a group of nine closely related bacterial species that might cause serious lung infections in cystic fibrosis patients, in some cases leading to death. In this paper the aggregation ability and the conformational properties of cepacian chain were investigated to understand its role in biofilm formation. Viscosity and at. force microscopy studies in water and in mixed (dimethylsulfoxide/water) solvent indicated the formation of double stranded mol. structures in aq. solns. Inter-residue short distances along cepacian chain were investigated by NOE NMR, which showed that two side chains of cepacian were not conformationally free due to strong interactions with the polymer backbone. These interactions were attributed to hydrogen bonding and contributed to structure rigidity.

IPCB graphical abstract



277) Comparative investigation of photo- and thermal-oxidation processes in poly(butylene terephthalate)

S.Carroccio, P.Rizzarelli, G.Scaltro, C.Puglisi

Polymer  49,  3371-3381  - 2008

Thermal- and photo-oxidation processes occurring in poly(1,4-butylene terephthalate) (PBT) were investigated and compared in order to find out potential dissimilarities in the oxidation pathways of this polymer. The oxidized compounds were analyzed by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Applications of MALDI to the study of polymer photo- and thermo-oxidation are quite recent and involve the collection of MALDI spectra at different irradiation times and/or temperatures to observe the structural changes induced by heat or light under an oxidizing atmosphere. The polymer sample can be directly analyzed and the recorded MALDI spectrum arises from a mixture of non-oxidized and oxidized chains. The results obtained by MALDI are highly informative, as compared with previous studies based on conventional techniques, yielding precise information on the size, structure, and end groups of molecules derived from the oxidation process. According to the structure of the compounds identified in this work, two thermal-oxidation processes and two photo-oxidation cleavages have been unambiguously ascertained to occur in PBT. Furthermore, the inspection of the data acquired by MALDI allowed discriminating the degradation mechanisms entirely induced by light or heat without the involvement of oxygen.


278) Self-Assembly Dynamics of Modular Homoditopic Bis-calix[5]arenes and Long-Chain á,ù-Alkanediyldiammonium Components

G.Gattuso, A.Notti, A.Pappalardo, M.F.Parisi, I.Pisagatti, S.Pappalardo, D.Garozzo, A.Messina, Y.Cohen, S.Slovak

Journal of Organic Chemistry  73(18),  7280-7289  - 2008

Homoditopic building blocks 1, featuring two π-rich cone-like calix[5]arene moieties connected at their narrow rims by a rigid o-, m-, or p-xylyl spacer in a centrosymmetric divergent arrangement, show a remarkable tendency to spontaneously and reversibly self-assemble with the complementary homoditopic α,ω-alkanediyldiammonium dipicrate guest salts C8−C12·2Pic through iterative intermolecular inclusion events, forming supramolecular assemblies whose composition and dynamics strongly depend upon the length of the connector, the geometry of the spacer, as well as the concentration and/or molar ratios between the two components. 1H NMR spectroscopy and ESI-MS studies of 1/Cn·2Pic modular homoditopic pairs support the formation of discrete (bis)-endo-cavity assemblies with the shorter C8 and C9 connectors, and/or (poly)capsular assemblies with the longer C10−C12 components under appropriate concentrations and molar ratios (50 mM equimolar solutions). 1H NMR titration experiments and diffusion NMR studies provide clear evidence for the self-assembly dynamics of the complementary pairs here investigated.


279) Multiplexed glycoproteomic analysis of glycosylation disorders by sequential yolk immunoglobulins immunoseparation and MALDI-TOF MS

L.Sturiale, R.Barone, A.Palmigiano, C.N.Ndosimao, P.Briones, M.Adamowicz, J.Jaeken, D.Garozzo

Proteomics  8(18),  3822-3832  - 2008

This study applied yolk immunoglobulins immunoaffinity separation and MALDI-TOF MS for clinical proteomics of congenital disorders of glycosylation (CDG) and secondary glycosylation disorders [galactosemia and hereditary fructose intolerance (HFI)]. Serum transferrin (Tf) and α1-antitrypsin (AAT) that are markers for CDG, were purified sequentially to obtain high-quality MALDI mass spectra to differentiate single glycoforms of the native intact glycoproteins. The procedure was found feasible for the investigation of protein macroheterogeneity due to glycosylation site underoccupancy then ensuing the characterization of patients with CDG group I (N-glycan assembly disorders). Following PNGase F digestion of the purified glycoprotein, the characterization of protein microheterogeneity by N-glycan MS analysis was performed in a patient with CDG group II (processing disorders). CDG-Ia patients showed a typical profile of underglycosylation where the fully glycosylated glycoforms are always the most abundant present in plasma with lesser amounts of partially and unglycosylated glycoforms in this order. Galactosemia and HFI are potentially fatal diseases, which benefit from early diagnosis and prompt therapeutic intervention. In symptomatic patients with galactosemia and in those with HFI, MALDI MS of Tf and AAT depicts a hypoglycosylation profile with a significant increase of underglycosylated glycoforms that reverses by dietary treatment, representing a clue for diagnosis and treatment monitoring.


280) Synthesis and characterization of novel polyamides from new aromatic phosphonate diamine monomer

P.Finocchiaro, G.A.Consiglio, A.Imbrogiano, S.Failla, F.Samperi, S.Bazzano, C.Puglisi, G.Scaltro

European Polymer Journal  44,  2639-2651  - 2008

New aliphatic-aromatic and fully aromatic phosphonate polyamides were prepared by polycondensation reaction of our synthesized aromatic diamine: tetraethyl[(2,5-diamino-3,6-dimethylbenzene-1,4-diyl)dimethanediyl]bis(phosphonate) with the specific di-acylchloride (adipoyl chloride, isophthaloyl chloride and terephthaloyl chloride). The chemical structure of all samples were characterized by (1H and 31P) NMR, MALDI-TOF MS, FT-IR tools, whereas their thermal properties were determined by DSC and TGA techniques. The phosponate polyadipamide (referred as PAP) is a semi-crystalline sample with a melting temperature at about 261° C and glass transition (Tg) of 71° C. All polymers show two thermal degradation steps in the temperature range 270-550° C. Each polymer, independently its structure, shows the first maximum rate of thermal decomposition temperature (PDT) around 300-310° C, which may be due to thermal degradation of phoshonate groups. MALDI-TOF spectra, beside the linear oligomers terminated with the specific groups expected in accord to the synthesis procedure, reveals the presence of cyclic oligomers in the polyadipamide and polyisophthalamide samples.


281) Clinical phenotype correlates to glycoprotein phenotype in a sib pair with CDG-Ia

R.Barone, L.Sturiale, V.Sofia, A.Ignoto, A.Fiumara, G.Sorge, D.Garozzo, M.Zappia

American Journal of Medical Genetics Part A  146A(16),  2103-2108  - 2008

Congenital disorder of glycosylation (CDG) type Ia (PMM2 mutations) is the most common genetic disorder of protein N-glycosylation. The wide clinical spectrum with mild to severe impairment of neurological function and extensive allelic heterogeneity hamper phenotype-genotype comparison. We report on two male adult siblings with the PMM2 mutations c. 385G > A (p.V129M) and c. 422G > A (p.R141H) and partially different clinical phenotype. Patient 2 has a more severe degree of neurological and systemic involvement and a more pronounced decrease in levels of serum glycoproteins. MALDI-TOF mass spectrometry of serum transferrin and alpha-1-antitrypsin shows more pronounced glycosylation defects in the more severely affected patient. Glycoproteomic analysis may reveal differences in CDG-Ia patients with different disease severity and might endorse clinical characterization of CDG-Ia patients.


282) Rhizobium rubiT: A Gram-Negative Phytopathogenic Bacterium Expressing the Lewis B Epitope on the Outer Core of its Lipooligosaccharide Fraction

V.Gargiulo, D.Garozzo, R.Lanzetta, A.Molinaro, L.Sturiale, C.De Castro, M.Parrilli

ChemBioChem  9(11),  1830-1835  - 2008

The structure of the core oligosaccharide from the phytopathogenic bacterium Rhizobium rubi was deduced by combining information from complementary chemical approaches (alkaline and acid hydrolysis), similar to the "overlap peptide" strategy. This structure is new and it contains two main oligosaccharide backbones that differ in the substitution degree of the external Kdo unit. The relevant feature shared by both oligosaccharides is the presence of a tetrasaccharide motif that is similar to the blood group Lewis B antigen (LeB). This epitope differs from LeB in the glycosidic configuration of the glucosamine unit (α and not β) and in the occurrence of acetyls substituents at O3 and/or O4 of the galactose moiety. Other notable structural features are the location of the Dha residue, the presence of a α-glucose unit that is linked to the inner Kdo unit, the high number of acid sugars and the highly branched core structure.


283) Structural characterization of synthetic poly(ester amide) from sebacic acid and 4-amino-1-butanol by matrixassisted laser desorption ionization time-of-flight/time-of-flight tandem mass spectrometry

P.Rizzarelli, C.Puglisi

Rapid Communications in Mass Spectrometry   22(6),  739-754  - 2008

Matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS/MS) was employed to analyze a poly(ester amide) sample (PEA-Bu) from the melt condensation of sebacic acid and 4-amino-1-butanol. In particular, we investigated the fragmentation pathways, the ester/amide bond sequences and the structure of species derived from side reactions during the synthesis. MALDI-TOF/TOF-MS/MS analysis was performed on cyclic species and linear oligomers terminated by dicarboxyl groups, carboxyl and hydroxyl groups and diamino alcohol groups. The sodium adducts of these oligomers were selected as precursor ions. Different end groups do not influence the fragmentation of sodiated poly(ester amide) oligomers and similar series of product ions were observed in the MALDI-TOF/TOF-MS/MS spectra. According to the structures of the most abundant product ions identified, the main cleavages proceed through a β-hydrogen-transfer rearrangement, leading to the selective scission of the -O-CH2- bonds. Abundant product ions originating from -CH2-CH2- (β-γ) bond cleavage in the sebacate moiety were also detected. Their formation should be promoted by the presence of an α,β-unsaturated ester or amide end group. MALDI-TOF/TOF-MS/MS provided structural information concerning the ester/amide sequences in the polymer chains. In the MALDI-TOF/TOF-MS/MS spectra acquired, using argon as the collision gas, of cyclic species and linear oligomers terminated by diamino alcohol groups, product ions in the low-mass range, undetected in the mass spectra acquired using air as the collision gas, proved to be diagnostic and made it possible to establish the presence of random sequences of ester and amide bonds in the poly(ester amide) sample. Furthermore, MALDI-TOF/TOF-MS/MS provided useful information to clarify the structures of precursor ions derived from side reactions during the synthesis.


284) Clinical and biochemical features in a Congolese infant with congenital disorder of glycosylation (CDG)-IIx

N.C.Nsibu, J.Jaeken, H.Carchon, M.Mampunza, L.Sturiale, D.Garozzo, M.N.L.Mashako, M.P.Tshibassu

European Journal of Paediatric Neurology  12,  257-261  - 2008

We describe an infant girl with psychomotor retardation, growth retardation, mild facial dysmorphy, evidence of liver involvement and a type 2 pattern of serum sialotransferrins. Serum transferrin glycan analysis with MALDI-TOF showed an extremely altered N-glycan pattern with a large number of truncated asialoglycans pointing to a severely defective Nglycan processing. The basic defect in this patient with CDG-IIx has not yet been identified.


285) The Acylation and Phosphorylation Pattern of Lipid A from Xanthomonas Campestris Strongly Influence its Ability to Trigger the Innate Immune Response in Arabidopsis

A.Silipo, L.Sturiale, D.Garozzo, G.Erbs, T.Tandrup Jensen, R.Lanzetta, J.Maxwell Dow, M.Parrilli, M.A.Newman, A.Molinaro

ChemBioChem  9(6),  896-904  - 2008

Lipopolysaccharides (LPSs) are major components of the cell surface of Gram-negative bacteria. LPSs comprise a hydrophilic heteropolysaccharide (formed by the core oligosaccharide and the O-specific polysaccharide) that is covalently linked to the glycolipid moiety lipid A, which anchors these macromolecules to the external membrane. LPSs are one of a group of molecules called pathogen-associated molecular patterns (PAMPs) that are indispensable for bacterial growth and viability, and act to trigger innate defense responses in eukaryotes. We have previously shown that LPS from the plant pathogen Xanthomonas campestris pv. campestris (Xcc) can elicit defense responses in the model plant Arabidopsis thaliana. Here we have extended these studies by analysis of the structure and biological activity of LPS from a nonpathogenic Xcc mutant, strain 8530. We show that this Xcc strain is defective in core completion and introduces significant modification in the lipid A region, which involves the degree of acylation and nonstoichiometric substitution of the phosphate groups with phosphoethanolamine. Lipid A that was isolated from Xcc strain 8530 did not have the ability to induce the defense-related gene PR1 in Arabidopsis, or to prevent the hypersensitive response (HR) that is caused by avirulent bacteria as the lipid A from the wild-type could. This suggests that Xcc has the capacity to modify the structure of the lipid A to reduce its activity as a PAMP. We speculate that such effects might occur in wild-type bacteria that are exposed to stresses such as those that might be encountered during plant colonization and disease.


286) Structural characterizations of lipids A by MS/MS of doubly charged ions on a hybrid linear ion trap/orbitrap mass spectrometer

A.Silipo, C.De Castro, R.Lanzetta, A.Molinaro, M.Parrilli, G.Vago, L.Sturiale, A.Messina, D.Garozzo

Journal of Mass Spectrometry  43,  478-484  - 2008

DOI: https://doi.org/10.1002/jms.1333
Here, a new "one pot" and fast approach is described, based on electrospray ionization (ESI) of negative ions by using a hybrid linear ion trap/orbitrap mass spectrometer (LTQ/orbitrap) for MS and MS/MS analysis. By this method the distribution of the primary and secondary acyl residues of the intact lipid A is inferred by analysis of the ESI spectra measured in positive and negative mode. The analysis of these data allows an unequivocal assignment of the fatty acid distribution. This methodology was successfully tested on two different lipid A with known structures, deriving from the Agrobacterium tumefaciens and Escherichia coli lipopolysaccharides.


287) Full structural characterization of Shigella flexneri M90T serotype 5 wild-type R-LPS and its ΔgalU mutant: glycine residue location in the inner core of the lipopolysaccharide

A.Molinaro, A.Silipo, C.De Castro, L.Sturiale, G.Nigro, D.Garozzo, M.L.Bernardini, R.Lanzetta, M.Parrilli

Glycobiology  18,  260-269  - 2008

Shigella flexneri is a Gram-negative bacterium responsible for serious enteric infections that occur mainly in the terminal ileum and colon. High interest in Shigella, as a human pathogen, is driven by its antibiotic resistance and the necessity to develop a vaccine against its infections.Vaccines of the last generation use carbohydrate moieties of the lipopolysaccharide as probable candidates. For this reason, the primary structure of the core oligosaccharide from the R-LPS produced by S. flexneri M90T serotype 5 using chemical analysis, nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MALDI), is herein reported. This is the first time that the core oligosaccharide primary structure by S. flexneri M90T is established in an unambiguous multidisciplinary approach. Chemical and spectroscopical investigation of the de-acetylated LPS showed that the inner core structure is characterized by a L,D-Hep-(1 →7)-L,D-Hep-(1 →3)-L,D-Hep-(1 →5)-[Kdo-(2 →4)]-Kdo sequence that is the common structural theme identified in Enterobacteriaceae. In particular, in S. flexneri M90T serotype 5 LPS, a glucosamine residue is additionally sitting at O-7 of the last heptose whereas the outer core is characterized by glucose and galactose residues. Also, in order to exactly define the position of glycine that is an integral constituent of the core region of the LPS, we created a S. flexneri M90T ΔgalU mutant and studied its LOS. In this way it was possible to establish that glycine is sitting at O-6 of the second heptose in the inner core.


288) Uncharged Water-Soluble Metal-Bis- Porphyrins Like Molecular Tweezers for Amino Acids

E.Scamporrino, P.Mineo, S.Dattilo, D.Vitalini, E.Spina

Macromolecular Rapid Communications  28,  1546-1552  - 2007

Some new water-soluble bis-porphyrins, constituted of two porphyrin units spaced by means of aliphatic bridges of different lengths, were synthesized and characterized by MALDI-TOF mass spectrometry, 1H NMR and UV-vis spectroscopy. The hydrosolubility of these uncharged compounds was guaranteed from the presence of six long PEG chains bound on the peripheral positions of the two porphyrins. Cobalt and zinc derivatives were also prepared. In the case of Co-bis-porphyrin, the appearance of induced circular dichroism (ICD) signals in water solution confirmed the formation of stable complexes with some amino acids, in which the bis-porphyrin behaves like molecular tweezers.



289) Self-assembly of a nucleotide-calixarene hybrid in a triangular supramolecule

G.M.L.Consoli, G.Granata, D.Garozzo, T.Mecca, C.Geraci

Tetrahedron Letters  48,  7974-7977  - 2007

The self-assembly of a thymine nucleotide-calixarene hybrid (1) in CDCl3 as a solvent was investigated. FT-IR, ESI-MS, 1H and DOSY-NMR spectra evidenced that compound 1 (ammonium or sodium salt) self-assembles in a triangular trimeric supramolecule by thymine-thymine hydrogen bonding. The saline form is crucial for the arrangement in the cyclic trimer as the protonation of the nucleotide phosphate groups leads the assembly toward a dimeric species.


290) Exopolysaccharides produced by Inquilinus limosus, a new pathogen of cystic fibrosis patients: novel structures with usual components

Y.Herasimenka, P.Cescutti, G.Impallomeni, R.Rizzo

Carbohydrate Research  342,  2404-2415  - 2007

The major cause of morbidity and mortality in patients with cystic fibrosis, an autosomal recessive disorder, is chronic microbial colonisation of the major airways that leads to exacerbation of pulmonary infection. Several different microbes colonise cystic fibrosis lungs, and Pseudomonas aeruginosa is one of the most threatening, since the establishment of mucoid (alginate producing) strains is ultimately associated with the patient?s death. Very recently a new bacterium, named Inquilinus limosus, was repeatedly found infecting the respiratory tract of cystic fibrosis patients. Its multi-resistance characteristic to antibiotics might result in the spreading of I. limosus infection among the cystic fibrosis community, as recently happened with strains of the Burkholderia cepacia complex. Since exopolysaccharides are recognised as important virulence factors in lung infections, the primary structure of the polysaccharide produced by I. limosus strain LMG 20952T was investigated as the first step in understanding its role in pathogenesis. The structure was determined by means of methylation analysis, acid degradations, mass spectrometry and NMR spectroscopy. The results showed that the bacterium produced a mixture constituted of the following polymers:

[3)-[4,6-O-(1-carboxyethylidene)]-β-D-Glcp(1→]n

[2)-[4,6-O-(1-carboxyethylidene)]-α-D-Manp(1→]n

Both polymers were completely substituted with pyruvyl ketal groups, a novel structural characteristic not previously found in bacterial polysaccharides. The absolute configuration of all pyruvyl groups was S. Inspection of possible local conformations assumed by the two polysaccharide chains showed features, which might provide interesting clues for understanding structure?function relationships.


291) Thermal decomposition products of copoly(arylene ether sulfone)s characterized by direct pyrolysis mass spectrometry

F.Samperi, C.Puglisi, T.Ferreri, R.Messina, G. Cicala, A.Recca, C.L.Restuccia, A.Scamporrino

Polymer Degradation and Stability  92(7),  1304-1315  - 2007

Pyrolysis products with mass of up to 850 Da were detected by direct pyrolysis mass spectrometric (DPMS) analysis of a series of copoly(arylene ether sulfone)s (PESePPO) synthesized by nucleophilic condensation of either 4,4’-dichlorodiphenylsulfone (CDPS) or 4,4’-bis-(4-chlorophenyl sulfonyl) biphenyl (long chain dichloride, LCDC) with different molar ratios of hydroquinone (HQ) or dihydroxydiphenylsulfone (HDPS). Pyrolysis products retaining the repeating units of the initial copolymers were formed at temperatures ranging from 420º C to 470º C (near the initial decomposition temperature). At temperatures higher than 450º C were observed products containing biphenyl units, formed by the elimination process of SO2 from diphenyl sulfone bridges. Products having biphenyl and dibenzofuran moieties were detected in the mass spectra recorded at temperatures above 550º C. These units were formed by loss of hydrogen atom from diphenyl ether bridges. Although the EI (18 eV) mass spectra of the pyrolysis products of the samples investigated were very similar, it was found that the relative intensity of some ions reflects the molar composition of the copolymers analysed. Cyclic and linear oligomers with very low molecular mass, present in the crude copolymers, were also detected by DPMS. Thermogravimetric analysis also showed their excellent thermal stability below 400º C. It indicates that the copolymers yield a char residue of 40–45% at 800º C, which increases with the PPO mole fraction in the samples.


292) Analysis of melt copolymers

M.S.Montaudo

European Journal of Mass Spectrometry  13,  61-67  - 2007

Melt copolymer chains are the main (most abundant) reaction product obtained when heating a blend of two (or more) condensation polymers (such as polyester + polycarbonate or polyester + polyamide or polyester + polyester) in which exchange reactions occur. In fact, during the melt-mixing reaction, an AB copolymer is formed and, as a consequence, the sample is a complex mixture made of three components or simply "parts", referred to as Z1, Z2 and Z3, where Z1 and Z2 are the parts for unreacted homo­polymers (A and B), whereas Z3 is the part for the copolymer. In this paper, it is shown that matrix-assisted laser desorption/­ionization mass spectrometry (and mass spectrometry in general) can be used to monitor the yield of the reactive blending reaction, YR, by ­measuring the amount of unreacted homopolymer (Z1 and Z2). In order to allow for comparisons, the paper also discusses conventional methods for measuring Z1 and Z2, such as liquid chromatography and nuclear magnetic resonance.


293) Amphiphilic N-Glycosyl-thiocarbamoyl Cyclodextrins: Synthesis, Self-Assembly, and Fluorimetry of Recognition by Lens culinaris Lectin

S.McNicholas, A.Rencurosi, L.Lay, A.Mazzaglia, L.Sturiale, M.Perez, R.Darcy

Biomacromolecules  8(6),  1851-1857  - 2007

Amphiphilic β-cyclodextrins have been synthesized bearing hexylthio, dodecylthio, and hexadecylthio chains at the 6-positions and glycosylthiocarbamoyl-oligo(ethylene glycol) units at the 2-positions. The glycosyl residues (α-D-mannosyl and β-L-fucosyl) are intended for cell-targeting. Self-assembly of these new amphiphilic glycosylated cyclodextrins in water to form vesicles was investigated by dynamic light scattering and transmission electron microscopy. Selective binding of the hexylthio assemblies to a protein receptor (Lens culinaris lectin) was confirmed by fluorescence spectroscopy.


294) Addition of glycerol plasticizer to seaweeds derived alginates: Influence of microstructure on chemical-physical properties

M.Avella, E.Di Pace, B.Immirzi, G.Impallomeni, M.Malinconico, G.Santagata

Carbohydrate Polymers  69,  503-511  - 2007

A study of the interaction among sodium alginates of different molecular compositions, water and glycerol was carried out, in order to weigh up the influence of different polymeric microstructures on the chemical–physical properties of films obtained by water soluble blends of sodium alginates and increasing amounts of glycerol. Thermal, mechanical and morphological analyses performed on the films confirmed the existence of specific interactions between sodium alginates and glycerol; it was as well demonstrated that only at specific mass ratio between the single polymers and glycerol it is possible to obtain the correct plasticizing effect induced by glycerol.


295) Detailed characterization of the lipid A fraction from the nonpathogen Acinetobacter radioresistens strain S13

S.Leone, L.Sturiale, E.Pessione, R.Mazzoli, C.Giunta, R.Lanzetta, D.Garozzo, A.Molinaro, M.Parrilli

Journal of Lipid Research  48,  1045-1051  - 2007

The genus Acinetobacter is composed of ubiquitous, generally nonpathogen environmental bacteria. Interest concerning these microorganisms has increased during the last 30 years, because some strains, belonging to the so-called A. baumannii-A. calcoaceticus complex, have been implicated in some severe pathological states in debilitated and hospitalized patients. The involvement of lipopolysaccharides (LPSs) as virulence factors in infections by Acinetobacter has been proven, and ongoing studies are aimed toward the complete serological characterization of the O-polysaccharides from LPSs isolated in clinical samples. Conversely, no characterization of the lipid A fraction from Acinetobacter strains has been performed. Here, the detailed structure of the lipid A fraction from A. radioresistens S13 is reported for the first time. A. radioresistens strains have never been isolated in cases of infectious disease. Nevertheless, it is known that the lipid A structure, with minor variations, is highly conserved across the genus; thus, structural details acquired from studies of this nonpathogen strain represent a useful basis for further studies of pathogen species.


296) The Complete Structure and Pro-inflammatory Activity of the Lipooligosaccharide of the Highly Epidemic and Virulent Gram-Negative Bacterium Burkholderia cenocepacia ET-12 (Strain J2315)

A.Silipo, A.Molinaro, T.Ieranò, A.De Soyza, L.Sturiale, D.Garozzo, C.Aldridge, P.A.Corris, C.M.Anjam Khan, R.Lanzetta, M.Parrilli

Chemistry-A European Journal  13,  3501-3511  - 2007

Members of genus Burkholderia include opportunistic Gram-negative bacteria that are responsible for serious infections in immunocompromised and cystic fibrosis (CF) patients. The Burkholderia cepacia complex is a group of microorganisms composed of at least nine closely related genomovars. Among these, B. cenocepacia is widely recognized to cause epidemics associated with excessive mortality. Species that belong to this strain are problematic CF pathogens because of their high resistance to antibiotics, which makes respiratory infections difficult to treat and impossible to eradicate. Infection by these bacteria is associated with higher mortality in CF and poor outcomes following lung transplantation. One virulence factor contributing to this is the pro-inflammatory lipopolysaccharide (LPS) molecules. Thus, the knowledge of the lipopolysaccharide structure is an essential prerequisite to the understanding of the molecular mechanisms involved in the inflammatory process. Such data are instrumental in aiding the design of antimicrobial compounds and for developing therapeutic strategies against the inflammatory cascade. In particular, defining the structure of the LPS from B. cenocepacia ET-12 clone LMG 16656 (also known as J2315) is extremely important given the recent completion of the sequencing project at the Sanger Centre using this specific strain. In this paper we address this issue by defining the pro-inflammatory activity of the pure lipopolysaccharide, and by describing its full primary structure. The activity of the lipopolysaccharide was tested as a stimulant in human myelomonocytic U937 cells. The structural analysis was carried out by compositional analysis, mass spectrometry and 2D NMR spectroscopy on the intact lipooligosacchride (LOS) and its fragments, which were obtained by selective chemical degradations.


297) Copper(II) complexes with β -cyclodextrin-homocarnosine conjugates and their antioxidant activity

F.Bellia, D.La Mendola, G.Maccarrone, P.Mineo, D.Vitalini, E.Scamporrino, S.Sortino, G.Vecchio, E.Rizzarelli

Inorganica Chimica Acta   360(3),  945-954  - 2007

Cu(II) complexes of the β-cyclodextrin (β-CD) functionalized with homocarnosine (Hc) in the primary (CDHC6) and secondary rim (CDHC3) were characterized by different spectroscopic techniques such as UV-visible absorption, CD, ESR and electron-spray mass spectrometry. Taken together, all the spectroscopic parameters indicate the formation of different Cu(II) complex species at various pH values. In the CDHC3 Cu(II) complex species, a direct involvement of the secondary hydroxyl Group 2 of functionalized β-CD's ring was pointed out. The antioxidant activity of the Cu(II) complexes of the two derivs. was detd. through pulse radiolysis measurements. The results obtained provide direct evidence for a high catalytic activity of both complexes towards the dismutation of the superoxide anion radical. Also the complex formation is not detrimental to the excellent scavenger activity exhibited by the ligands alone towards hydroxyl radicals. These Cu complexes then represent very intriguing antioxidant agents against known toxic reactive O species.


298) Sequencing Microbial Copolymers of 3-Hydroxybutyric and 3-Mercaptoalkanoic Acids by NMR, Electrospray Ionization Mass Spectrometry, and Size Exclusion Chromatography NMR

G.Impallomeni, A.Steinbuechel, T.Luetke-Eversloh, T.Barbuzzi, A.Ballistreri

Biomacromolecules  8(3),  985-991  - 2007

Copolymers of 3-hydroxybutyrate (3HB) and 3-mercaptopropionate (3MP) or 3-mercaptobutyrate (3MB) units and minor amts. of 3-hydroxypropionate (3HP), 3-hydroxyvalerate (3HV), or 3-mercaptovalerate (3MV) were investigated regarding their microstructure by NMR, electrospray ionization mass spectrometry, and size exclusion chromatog. NMR. These copolymers were produced by Ralstonia eutropha strain H16 when cells were cultivated in a mineral salts medium with gluconate as a carbon source for growth and 3MP or 3MB as precursor substrates for incorporation of 3-mercaptoalkanoates. Mass spectrometry anal. of partially methanolyzed or pyrolyzed samples proved the presence of true copolymers or terpolymers. 13C NMR spectroscopy of intact polymer samples, with values of av. block length and degree of randomness deviating from a random sequence model, suggested microblock structures; however, compn. anal. by 1H NMR of fractions obtained by size exclusion chromatog. showed significant variations with mol. wt., revealing the presence of blends of poly(3HB-co-3MP-co-3HP) or poly(3HB-co-3MB) with poly(3HB). The exptl. NMR carbonyl dyad signal intensities were satisfactorily matched by a random sequence model when the presence of poly(3HB) was taken into account.


299) Exopolysaccharides produced by clinical strains belonging to the Burkholderia cepacia complex

Y.Herasimenka, P.Cescutti, G.Impallomeni, S.Campana, G.Taccetti, N.Ravenni, F.Zanetti, R.Rizzo

Journal of Cystic Fibrosis  6(2),  145-152  - 2007

Background: In the frame of a research line dedicated to better clarify the role of exopolysaccharides (EPS) in bacterial virulence, EPS produced by species of the Burkholderia cepacia complex (Bcc), namely Burkholderia multivorans, Burkholderia cenocepacia, and a Bcc member of undetd. genomovar, all isolated at the Cystic Fibrosis Regional Center of Florence (Italy), were investigated for they structural properties. Methods: Three strains of B. multivorans, three of B. cenocepacia and one of a Bcc member of undetd. genomovar were isolated from CF patients. The ref. strains C1576 and J2315, for genomovar II and III, resp., were included in the study. The bacteria were grown on solid media, the exopolysaccharides produced were purified, and their structures were detd. In addn., sugar anal. of sputum samples was accomplished to search for EPS produced in vivo. Results: Six strains out of seven produced the exopolysaccharide cepacian, while one strain of B. multivorans produced a completely different polymer, previously known in the literature as PS1. Two strains synthesized very small amts. of EPS. No definitive evidence for the presence of cepacian in sputum samples was found. Conclusions: Most strains examd. produced abundant amts. of polysaccharides. Cepacian was the most common EPS isolated and its prodn. was not assocd. to a particular genomovar


300) Syntheses, Structures, and Anion-Binding Properties of Two Novel Calix[2]benzo[4]pyrroles

G.Cafeo, F.H.Kohnke, A.J.P.White, D.Garozzo, A.Messina

Chemistry-A European Journal  13,  649-656  - 2007

Calix[2]benzo[4]pyrrole m-6 and p-6, each containing two dipyrromethane moieties and two m-phenylene or p-phenylene units, respectively, were readily synthesised from pyrrole, 1,3- and 1,4-bis(1,1’-dimethylhydroxymethyl)benzene, (m-4 and p-4, respectively) and acetone. Macrocycles m-6 and p-6 were tested as receptors for a selection of anions, such as acetate, dihydrogenphosphate and fluoride. The X-ray structures of m-6 and p-6 and those of the complexes m-6-F-, m-6-Cl- and m-6-CH3COO- (with an nBu4N+ counterion) were also determined.


301) The Outer Membrane of the Marine Gram-Negative Bacterium Alteromonas addita is Composed of a Very Short-Chain Lipopolysaccharide with a High Negative Charge Density

S.Leone, A.Molinaro, L.Sturiale, D.Garozzo, E.L.Nazarenko, R.P.Gorshkova3, E.P.Ivanova, L.S.Shevchenko, R.Lanzetta, M.Parrilli

European Journal of Organic Chemistry  2007(7),  1113-1122  - 2007

The complete structure of the lipopolysaccharide isolated from the Gram-negative marine bacterium Alteromonas addita, type strain KMM 3600T = R10SW13T, has been elucidated by means of a combined chemical approach and state-of-the-art NMR and MS analyses. Isolation and characterisation of the lipid A moiety and the core oligosaccharide were pursued separately after either acid or alkaline treatment of the lipopolysaccharide. The structure detected was identified as a novel, highly negatively charged, deep-rough lipopolysaccharide in which a trisaccharide subunit is connected to a typical lipid A glucosamine backbone. Within the core oligosaccharide, a phosphodiester bridge connects a glucose unit to a heptose residue.


302) Borderline mental development in a congenital disorder of glycosylation (CDG) type Ia patient with multisystemic involvement (intermediate phenotype)

R.Barone, L.Sturiale, A.Fiumara, G.Uziel, D.Garozzo, J.Jaeken

Journal of Inherited Metabolic Disease  30,  107  - 2007

CDG Ia (phosphomannomutase deficiency) has a wide clinical spectrum with the most severe affected patients having multisystemic disease in addition to severe nervous system involvement. We report a patient with CDG Ia and an intermediate phenotype due to mild neurological impairment and borderline cognitive abilities despite the occurrence of typical extraneurological symptoms. These included liver involvement, coagulopathy and failure to thrive with enteropathy. Genotype analyses showed that he was compound heterozygous for T237R/C241S mutations. This observation underlines that the CDG Ia clinical spectrum may include intraindividual variability that might reflect different degrees of glycosylation abnormalities among distinct body compartments. CDG Ia should be considered in cases of unexplained liver involvement and/or enteropathy in patients with mild developmental delay and subtle neurological signs.


303) Microbial community dynamics during assays of harbour oil spill bioremediation: a microscale simulation study

S.Cappello, G.Caruso, D.Zampino, L.S.Monticelli, G.Maimone, R.Denaro, B.Tripodo, M.Troussellier, M.Yakimov, L.Giuliano

Journal of Applied Microbiology  102,  184-194  - 2007

Aims: Microcosm experiments simulating an oil spill event were performed to evaluate the response of the natural microbial community structure of Messina harbour seawater following the accidental load of petroleum. Methods and Results: An experimental harbour seawater microcosm, supplemented with nutrients and crude oil, was monitored above 15 days in comparison with unpolluted ones (control microcosms). Bacterial cells were counted with a Live/Dead BacLight viability kit; leucine aminopeptidase, b-glucosidase, alkaline phosphatase, lipase and esterase enzymes were measured using fluorogenic substrates. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil addition stimulated an increase of the total bacterial abundance, leucine aminopeptidase and phosphatase activity rates, as well as a change in the community structure. This suggested a prompt response of micro-organisms to the load of petroleum hydrocarbons. Conclusions: The present study on the viability, specific composition and metabolic characteristics of the microbial community allows a more precise assessment of oil pollution. Both structural and functional parameters offer interesting perspectives as indicators to monitor changes caused by petroleum hydrocarbons. Significance and Impact of the Study: A better knowledge of microbial structural successions at oil-polluted sites is essential for environmental bioremediation. Data obtained in microcosm studies improve our understanding of natural processes occurring during oil spills.


304) Matrix-assisted laser desorption/ionization time-of-flight investigation of Nylon 6 and Nylon 66 thermo-oxidation products

S.Carroccio, C.Puglisi, G.Scaltro, T.Ferreri, G.Montaudo

European Journal of Mass Spectrometry  13,  397-408  - 2007

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) was used to determine the structure of the molecules produced in the thermo-oxidative degradation of Nylon 6 and Nylon 66, at 180°C and 250°C in air. The MALDI spectra of the thermo-oxidized nylons provide information on the structure and end groups of the oligomers produced in the oxidation process. Our results show that the thermo-oxidation of both Ny6 and Ny66 proceeds through a hydrogen abstraction and subsequent formation of hydroperoxide intermediates. The latter decompose, yielding oligomers containing aldehydes, amides and methyl terminal groups. The aldehydes undergo further oxidation to produce carboxylic end groups. The formation of cyclopentanone terminal groups is also observed in the case of Nylon 66. Oligomers with structures deriving from Norrish-type degradation processes were not detected here for either Ny6 or Ny66.


305) Similarities and Differences among Monolayers of a Free Base Porphyrin and Its Copper Complex: Synthesis and Characterization of a Luminescent Copper(II) Porphyrin Monolayer

A.Gulino, I.Fragala, E.Scamporrino, D.Vitalini

Journal of Physical Chemistry C  111(38),  14125-14130  - 2007

SiO2 substrates were functionalized with a covalent 4-ClCH2C6H4SiCl3 monolayer. Addnl. covalent bonding of the 5,10,15-tri-(p-dodecanoxyphenyl)-20-(p-hydroxyphenyl) Cu porphyrin to the silylated substrates was further achieved. The optical properties of this robust monolayer system were studied at room temp. by both UV-visible and photoluminescence measurements. The UV-visible spectrum reveals the Soret band and of a Q-band envelope only. The surface chem. characterization was carried out by x-ray photoelectron measurements. The N 1s spectrum shows two peaks in tune with the Cu porphyrin axial grafted to the silylated substrate. Luminescence measurements gave emission intensity values larger than those obsd. for the free base monolayer.


306) Uncharged water-soluble porphyrin tweezers as a supramolecular sensor for α -amino acids

V.Villari, P.Mineo, N.Micali, N.Angelini, D.Vitalini, E.Scamporrino

Nanotechnology  18(37),  375503/1  - 2007

The binding between uncharged cobalt porphyrin tweezers and L-amino acids in aq. solns. is studied by means of UV-vis and CD spectroscopy. By varying the length of the aliph. bridge between the two porphyrin units, the no. of cobalt ions in the porphyrin cores and the pH of the soln., the chirality induction phenomenon has been investigated. The binding of the amino acid to the porphyrin seems to occur via a coordination mechanism between the metal and the nitrogen of the amino group; the steric, hydrophobic and π-π interactions operate to stabilize the complexes. The chirogenesis displays an opposite behavior in the presence of arom. guests with respect to the non-arom. ones. Moreover, the UV-vis and the induced CD spectral changes suggest that the amino acid arrangement in the tweezers is detd. by many factors, so that, unlike in org. solvent, the porphyrin tweezers in aq. soln. allow for two different arrangements of the same arom. amino acid. The exptl. findings indicate that the porphyrins tweezers reported in the paper are promising in opening perspectives toward their application as a selective mol. sensor in aq. solns. directly.


307) Fluorescent antibody-viability staining and β-glucuronidase assay as rapid methods for monitoring Escherichia coli viability in coastal waters

G.Caruso, F.De Pasquale, M.Mancuso, D.Zampino, E.Crisafi

Journal of Immunoassay & Immunochemistry  27,  1-13  - 2006

A faecal pollution monitoring of coastal Messina waters was performed by comparing three (microscopic, enzyme, and culture) methods. Evidence of Escherichia coli cells (29.99 to 96.79% of the total enteropathogenic serotypes) retaining their viability into the marine environment was shown. β-Glucuronidase activity rates suggested that living cells were also metabolically active. Heavily polluted sites were detected, where improperly treated urban wastes were discharged. Significant relationships between microscopic and enzymatic data proved both methods to be suitable alternatives to the culture method for E. coli detection, improving environmental quality assessment.


308) Advances in Purification Methods of Serum Glycoproteins for MALDI-MS Analysis of N- Glycome in Patients with Glycosylation Disorders

L.Sturiale, R.Barone, D.Garozzo

Glycobiology  16(11),  1135  - 2006

Genetic defects of the N-glycosylation pathway, named Congenital Disorders of Glycosylation (CDGs), result in abnormalities of N-glycome with aberrant glycan structures and changes in the relative levels of normal glycan moiety. Understanding N-glycan profile may be useful for characterization of known CDG types and to identify glycosylation processing defects in unsolved patients. CDG are heterogeneous disorders with variable clinical findings and multisystem involvement. As glycosylation defects are usually associated with abnormal glycoprotein folding and activity, it is plausible that the variety of clinical signs in CDG underlies abnormalities in a plethora of glycosylated molecules. Serum Transferrin was widely used so far to characterize N-glycan profile in patients with CDG; an alternative approach was based on the analysis of N-linked glycan released from total plasma. Our present work on N-glycome analyses in patients with CDG and related disorders is based on the systematic characterization, in addition to Transferrin, of multiple abundant serum glycoproteins, including acute-phase proteins. On this regard, we are working for creation of N-glycan profiling panel of each patient by the following steps: 1) purification of target glycoproteins by using sequentially, selective immunoaffinity columns on a few amount of unique serum sample. 2) characterization of the intact glycoprotein by MALDI mass spectrometry: this fundamental step allows us to analyze the rate and extent of deglycosylation (N-glycosylation site underoccupancy). 3) MALDI analyses of N-glycan structures. The observed occurrence of underglycosylation and abnormal glycan structure of AAT in CDG-Ia may link to possible unbalance of protease/antiprotease system in these patients.


309) Lower rim arylation of calix[n]arenes with extended perfluorinated domains

S.Buscemi, A.Pace, A.Palumbo Piccionello, S.Pappalardo, D.Garozzo, T.Pilati, G.Gattuso, A.Pappalardo, I.Pisagatti, M.F.Parisi

Tetrahedron Letters  47,  9049-9052  - 2006

Exhaustive O-arylation of p-tert-butylcalix[n]arenes 2 (n = 4-8) with an excess of 3-pentadecafluoroheptyl-5-pentafluorophenyl- 1,2,4-oxadiazole 3 and K2CO3 in refluxing acetonitrile provides an easy entry to a new family of perfluorinated calix[n]arenes 1. The cyclic tetramer furnishes a mixture of cone, partial cone, and 1,2-alternate conformers, while the larger macrocycles afford single products. The structures of all new compounds are substantiated by NMR techniques and MALDI-TOF mass spectral data. Single-crystal X-ray diffraction studies on the pentamer derivative 1b reveal a distorted cone-in conformation of the calixarene cup.


310) Full Characterization of a Multiblock Copolymer Based on Poly(2,6-dimethyl-1,4-phenylene oxide) and Poly(bisphenol-A carbonate)

F.Samperi, R.Mendichi, L.Sartore, M.Penco, C.Puglisi

Macromolecules  39(26),  9223-9233  - 2006

Full characterization, that is the true molar mass distribution and block sequence, of a multiblock copolymer based on poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and poly(bisphenol A carbonate) (PC) segments (PPO-b-PC), synthesized by polycondensation reaction of both diol-terminated PPO and PC samples with the bischloroformate of bisphenol A, is reported. The initial diol terminated PPO sample contains a few tetramethyl bisphenol A units in the backbone. The molar mass distribution of the starting PPO and PC homopolymers and the multiblock structure of the final PPO-b-PC copolymers were studied by light scattering and viscometry online with a SEC system, MALDI-TOF mass spectrometry, and NMR. In a previous study, we have demonstrated that homogeneous PPO-b-PC block copolymers having only one single Tg were obtained if low molar mass PPO and PC starting blocks were used. More important findings of this recent study are the following. MALDI-TOF analysis showed that the synthesized PPO-b-PC copolymers were composed of multiblock PPO-b-PC chains and also of some nonreacted PC oligomers terminated with methyl carbonate groups. Exhaustive and selective aminolysis of carbonate groups of the PC blocks has been also performed in order to determine the number of blocks and the average length of PPO blocks in the copolymers.


311) On the Preparation and Characterization of Polyethylene/Polyamide Blends by Melt Processing in the Presence of an Ethylene/Acrylic Acid Copolymer and of New Phosphazene Compounds

R.Scaffaro, M.C.Mistretta, F.P.La Mantia, M.Gleria, R.Bertani, F.Samperi, C.Puglisi

Macromolecular Chemistry and Physics  207,  1986-1997  - 2006

Samples of HDPE and PA6 have been meltprocessed in the presence of two new phosphazene compounds, CP-2EPOX and CP-2OXA together with an ethylene/acrylic acid copolymer. The blends have been prepared in an industrial twin-screw extruder by using PA6 and PE in weight ratios of 25/75 and 75/25. When used, 5 phr of EAA and 0.2 phr of CP have been added. The materials have been completely characterized from a rheological, morphological, and mechanical point of view. The results indicate that the additives used caused an increase in the rupture tensile properties, of the impact strength and viscosity especially in the PE-rich blend in the presence of CP-2EPOX. This result can be attributed both to a chain extension reaction on EAA and PA6 phases and on compatibilization effect due to the possible formation of EAA-g-PA6 copolymers. This latter occurrence is suggested by an improved adhesion between the phases and by an increased turbidity observed in the Molau tests. Between the two compatibilizers, the CP-2EPOX displays the overall best results, especially for the PE-based blends.


312) Novel Therapeutic Agents for Bone Resorption. Part 1. Synthesis and Protonation Thermodynamics of Poly(amido-amine)s Containing Bis-phosphonate Residues

M.Casolaro, I.Casolaro, A.Spreafico, C.Capperucci, B.Frediani, R.Marcolongo, N.Margiotta, R.Ostuni, R.Mendichi, F.Samperi, T.Ishii, Y.Ito

Biomacromolecules  7(12),  3417-3427  - 2006

Two poly(amido-amine)s (oligoPAM and oligoNER) contg. bis-phosphonate residues were obtained by a Michael-type polyaddn. of pamidronate and neridronate to 1,4-bis(acryloyl)piperazine. The SEC (size-exclusion chromatog.) and the MALDI-TOF (matrix assisted laser desorption ionization) analyses were consistent with the presence of oligomeric species (2-3 kDa) and with a narrow polydispersity index. The thermodn. results (log Ks, -Δ H° , and Δ S° obtained at 25°C in 0.15 M NaCl) of both the oligomers and the corresponding low mol. wt. precursors were in line with a cluster structure formed during the protonation of the basic nitrogen in the pamidronate. The soly. of the oligoNER with a longer aliph. chain was improved at high pHs, allowing the evaluation of their soln. properties. Preliminary biol. results show that both the oligomers do not neg. affect the in vitro viability, proliferation, and cellular activity of either normal animal or human osteoblasts.


313) Synthesis and matrix-assisted laser desorption/ionization time-of-flight characterization of bisphenol-A copolyformals containing nickel(II)/Schiff base, eicosane and 2-butene units in the main chain

D.Vitalini, E.Spina, R.Rapisardi, E.Scamporrino, P.Mineo

Rapid Communications in Mass Spectrometry   20(19),  2961-2968  - 2006

Some bisphenol-A copolyformals, contg. in the main chain different amts. of a Ni-diimine nonlinear optical (NLO)-chromophore, eicosane and/or 2-butene units, were synthesized by condensation reaction between dibromomethane and suitable mixts. of Ni(II)/Schiff base complex, 1,20-di(bisphenol-A)ether-eicosane and/or 1,4-di(bisphenol-A)ether-2-butene. Structural compn. and thermal properties of polymeric materials were inferred by analyses by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), NMR (NMR), gel permeation chromatog. (GPC), differential scanning calorimetry (DSC) and thermogravimetry (TG). MALDI-TOF data show that both Ni-diimine and unsatd. units are present in the copolyformals with a homogeneous arrangement in all the polymer mass range (GPC data). It has also been ascertained that the glass transition temp. (Tg) of the copolymers changes as a consequence of the abundance of aliph. units in the macromols. (DSC data). Crosslinking expts. of the copolymer at temps. near the Tg value and under UV irradn. were also performed.


314) Structural Analysis of the Deep Rough Lipopolysaccharide from Gram Negative Bacterium Alteromonas macleodii ATCC 27126T: The First Finding of β-Kdo in the Inner Core of Lipopolysaccharides

V.Liparoti, A.Molinaro, L.Sturiale, D.Garozzo, E.L.Nazarenko, R.P.Gorshkova, E.P.Ivanova, L.S.Shevcenko, R.Lanzetta, M.Parrilli

European Journal of Organic Chemistry  2006(20),  4710-4716  - 2006

Alteromonas macleodii ATCC 27126T is a Gram-negative marine bacterium isolated from a sea water sample collected from around the Hawaiian Islands. The structure of the lipooligosaccharide derived from its outer membrane has been fully determined using either alkaline or acid hydrolysis. Alkaline treatment, aimed at recovering the complete carbohydrate backbone, was carried out by mild hydrazinolysis (de-O-acylation) followed by de-N-acylation using hot KOH and furnished a single core glycoform. Mild acid hydrolysis was employed to obtain the lipid A moiety which was selectively de-O-acylated and analysed to determine its primary structure. The structural elucidation of both fractions was carried out by chemical analyses, 2D NMR spectroscopy and MALDI-TOF mass spectrometry and revealed a novel lipooligosaccharide with an unusual structure.


315) Full Structural Characterisation of the Lipooligosaccharide of a Burkholderia pyrrocinia Clinical Isolate

A.Silipo, A.Molinaro, D.Comegna, L.Sturiale, P.Cescutti, D.Garozzo, R.Lanzetta, M.Parrilli

European Journal of Organic Chemistry  2006(21),  4874-4883  - 2006

This paper deals with the full structural elucidation of the lipooligosaccharide from the Gram-negative bacterium Burkholderia pyrrocinia. B. pyrrocinia is one of the nine species included in the Burkholderia cepacia complex (BCC), a group of important opportunistic pathogens in patients with cystic fibrosis and chronic granulomatous disease. B. pyrrocinia strain BTS7, isolated from a patient with cystic fibrosis, was found to exclusively produce a lipooligosaccharide (LOS). This component of the external membrane plays a key role in the virulence of BCC bacteria and is required for resistance to antimicrobial compounds and for bacterial survival. Here we present, for the first time, a detailed study of the structure of the lipooligosaccharide (LOS) elucidated by means of compositional analysis, MALDI and ESI mass spectrometry and 2D NMR spectroscopy. The LOS of B. pyrrocinia was degraded by complete deacylation, dephosphorylation and reduction. The major oligosaccharide representing the carbohydrate backbone was isolated by size-exclusion chromatography and identified. The structural determination of molecules (such as the LOS of B. pyrrocinia) involved in the activation of the pro-inflammatory processes is the first step in the adoption of new therapeutic strategies against lung infections.


316) Preparation of Block Copolymers with a Single Tg Based on Segments of Poly(oxy-2,6-dimethyl-1, 4-phenylene) and Polycarbonate of Bisphenol A

M.Penco, L.Sartore, S.Della Sciucca, L.Di Landro, R.Mendichi, F.Samperi

Macromolecular Chemistry and Physics  207,  1492-1500  - 2006

The synthesis and the properties of block copolymers based on PPO and PC segments are reported. Copolymers that have a multi-block structure are synthesized by a polycondensation reaction that employs oligomeric PPO and PC diol terminated with phosgene or bischloroformate of bisphenol A. In the reaction scheme two steps are involved: first, the reaction of one of the oligomeric diols (PPO or PC) with the bischloroformate or phosgene; second, the oligomeric bischloroformate is reacted with the other diol. The molecular characteristics of the prepared samples are studied by SEC, 1H and 13C NMR, and FT-IR spectroscopy. The thermal and rheological properties and the thermal stability have also been investigated bymeans ofDSC, rotational rheometry, andTGA, respectively. Polymers that have a single glass transition temperature are obtained if low-molecular-weight segments are used. From a rheological point of view, thesematerials show a remarkably lower melt viscosity compared with a PPO homopolymer that has a comparable average molecular weight.


317) Structural analysis of the polysaccharides from Echinacea angustifolia radix

R.Cozzolino, P.Malvagna, E.Spina, A.Giori, N.Fuzzati, A.Anelli, D.Garozzo, G.Impallomeni

Carbohydrate Polymers  65,  263-272  - 2006

In this paper we report the characterization by monosaccharide and linkage analyses and by NMR spectroscopy and size exclusion chromatography of the carbohydrate fraction extracted from Echinacea angustifolia radix. In addition, the products of endo-pectin lyase, endo-pectate lyase, endo-polygalacturonase, endo-galactanase, and endo-arabinase digestion were characterized by MALDI-TOF mass spectrometry. The data obtained during this study showed that the carbohydrate fraction extracted from E. angustifolia radix is constituted by two polysaccharides with molecular weight of about 128,000 and 4500 Da. The low molecular weight polysaccharide corresponds to inulin while the high molecular weight component is a high metoxy pectin in which the backbone structure of the smooth region is constituted by α-(1-4)-polygalacturonan partially methyl esterified (60%) and acetylated (9%) and with the hairy regions containing 2-O- and 2,4-O-rhamnopyranose, 5-O- and 3,5-O-arabinofuranose, 3,6-galactopyranose, and terminal rhamnopyranose, arabinofuranose, arabinopyranose, galactopyranose, and galacturonopyranose. Mass spectrometry data of a galactanase treated sample showed evidence of a novel structure in the pectin hairy region, namely a galactose-galacturonic acid alternating sequence.


318) Effect of adding new phosphazene compounds to poly(butylene terephthalate)/polyamide blends. II: Effect of different polyamides on the properties of extruded samples

R.Scaffaro, L.Botta, F.P.La Mantia, M.Gleria, R.Bertani, F.Samperi, G.Scaltro

Polymer Degradation and Stability  91(10),  2265-2274  - 2006

Poly(butylene terephthalate) (PBT) and a sample of polyamide have been melt processed in the presence of two new phosphazene compounds, namely 2,2-dichloro-4,4,6,6-bis[spyro(2′,2"-dioxy-1′,1"-biphenyl)]cyclotriphosphazene (2Cl-CP) and 2,2-bis(2-methoxy-4-methyleneoxy-phenoxy)-4,4,6,6-bis[spyro(2′,2"-dioxy-1′,1"-biphenyl)]cyclophosphazene (CP-2EPOX). The blends were prepared by using polyamide 6 (PA6) and polyamide 6,6 (PA66) in 25/75 and 75/25 w/w compositions by using a co-rotating twin-screw extruder. The materials have been completely characterized from a mechanical, rheological, and morphological point of view. The results indicate that the additives used cause an increase of the rupture properties and of the viscosity, especially in the PA6 rich blends containing CP-2EPOX. This result can be not only attributed to a chain extension effect on the PA phase but also to in situ formation of PA/PBT copolymers promoted by the presence of the CP compound as confirmed by NMR and MALDI-TOF analyses. The compatibilization effect fades in blends containing PA66, probably due to a thermal deactivation of the additives at higher temperature required to process this polymer. The materials have been completely characterized from a mechanical, rheological, and morphological point of view. The results indicate that the additives used cause an increase of the rupture properties and of the viscosity, especially in the PA6 rich blends containing CP-2EPOX. This result can be not only attributed to a chain extension effect on the PA phase but also to in situ formation of PA/PBT copolymers promoted by the presence of the CP compound as confirmed by NMR and MALDI-TOF analyses. The compatibilization effect fades in blends containing PA66, probably due to a thermal deactivation of the additives at higher temperature required to process this polymer.


319) Strapped Calix[2]furan[4]pyrroles, Novel Examples of Ditopic Molecular Receptors

G.Cafeo, A.Kaledkowski, F.H. Kohnke, A.Messina

Supramolecular Chemistry  18(3),  273-279  - 2006

The cyclocondensation of polyether chains functionalised with dipyrromethane units at both ends with 2,5-bis[(α-hydroxy-α,α-dimethyl)methyl]furan yield novel strapped calix[2]furan[4]pyrroles. These receptors were studied for their ability to act as ion-pair ligands towards fluoride salts.


320) Matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectra of poly(butylene adipate)

P.Rizzarelli, C.Puglisi, G.Montaudo

Rapid Communications in Mass Spectrometry  20(11),  1683-1694  - 2006

Matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS/MS) was employed to analyze four poly(butylene adipate) (PBAd) oligomers and to investigate their fragmentation pathways as a continuation of our work on the MALDI-TOF/TOF-MS/MS study of synthetic polymers. MALDI-TOF/TOF-MS/MS analysis was performed on oligomers terminated by carboxyl and hydroxyl groups, methyl adipate and hydroxyl groups, dihydroxyl groups, and dicarboxyl groups. The sodium adducts of these oligomers were selected as precursor ions. Different end groups do not influence the fragmentation of sodiated polyester oligomers and similar series of product ions were observed in all the MALDI-TOF/TOF-MS/MS spectra. According to the structures of the most abundant product ions identified in the present work, three fragmentation pathways have been proposed to occur most frequently in PBAd:β-hydrogen-transfer rearrangement, leading to the selective cleavage of the —O—CH2—bonds;—CH2—CH2— (β—β) bond cleavage in the adipate moiety; and ester bond scission.


321) Spectroscopic and Microscopic Characterization and Behavior of an Optical pH Meter Based on a Functional Hybrid Monolayer Molecular System: Porphyrin Molecules Covalently Assembled on a Molecularly Engineered Silica Surface

A.Gulino, P.Mineo, E.Scamporrino, D.Vitalini, I.Fragala

Chemistry of Materials   18(9),  2404-2410  - 2006

A covalently assembled monolayer of 5,10,15-tri{p-[9-methoxy-tri(ethyleneoxy)]phenyl}20(p-hydroxyphenyl)porphyrin mols. on a silica substrate was fabricated and characterized by X-ray photoelectron spectra, AFM images, and UV-vis measurements. In addn., its [H3O+] optical sensing behavior was studied and compared to that of the parent water-sol. star polymer 5,10,15,20-tetrakis{p-[ω-methoxy-poly(ethyleneoxy)]phenyl}porphyrin having .apprx.40 repetitive units in each of the poly(oxyethylene) branches. Upon immersion in increasingly acidic solns., the UV-vis absorbance spectra of the porphyrin-assembled monolayer show the gradual disappearance of the Soret band at 427.2 nm and the progressive increase of a new band at 459.1 nm. In strongly acidic solns. (pH 1.0), the spectrum is substantially dominated by the new band and remains unchanged even with more acidic solns. The simple washing with water and drying under a N2 gas stream totally recovers the starting Soret signal. The presence of Mn(II), Co(II), Ni(II), Cd(II), or Pb(II) ions in water soln. does not interfere with the behavior of the present optical acid pH meter. In contrast, the presence of Hg(II), Cu(II), or Zn(II) ions changes the pH-metering performance due to formation of metal-porphyrin complexes as revealed by UV-vis and MALDI-TOF measurements of metal-contg. solns. of the similar 5,10,15,20-tetrakis{p-[ω-methoxy-poly(ethyleneoxy)]phenyl}porphyrin with .apprx.17 repetitive units in each poly(oxyethylene) branch.


322) First report of a lyase for cepacian, the polysaccharide produced by Burkholderia cepacia complex bacteria

P.Cescutti, S.Scussolin, Y.Herasimenka, G.Impallomeni, M.Bicego, R.Rizzo

Biochemical and Biophysical Research Communications   339(3),  821-826  - 2006

Bacteria belonging to the Burkholderia cepacia complex (Bcc) are interesting for their involvement in pulmonary infections in patients affected by cystic fibrosis (CF) or chronic granulomatous disease. Many Bcc strains isolated from CF patients produce high amts. of exopolysaccharides (EPS). Although different strains sometimes biosynthesize different EPS, the majority of Bcc bacteria produce only one type of polysaccharide, which is called cepacian. The polymer has a unique heptasaccharidic repeating unit, contg. three side chains, and up to three O-acetyl substituents. We here report for the first time the isolation and characterization of a lyase active towards cepacian produced by a Bacillus sp., which was isolated in our lab. The enzyme mol. mass, evaluated by size-exclusion chromatog., is 32,700±1500 Da. The enzyme catalyzes a β-elimination reaction of the disaccharide side chain β-D-Galp-(1→2)-α-D-Rhap-1→ from the C-4 of the glucuronic acid residue present in the polymer backbone. Although active on both native and de-acetylated cepacian, the enzyme showed higher activity on the latter polymer.


323) Combined MALDI-TOF MS and NMR characterization of copoly(arylen ether sulphone)s

C.Puglisi, F.Samperi, G.Cicala, A.Recca, C.L.Restuccia

Polymer  47(6),  1861-1874  - 2006

The synthesis and the chem. characterization of some novel random copolyethersulfones of the type P(ESES-co-EES) (Polyethersulfone-ethersulfone:Polyetherethersulfone), is reported. The ESES:EES molar ratio was varied from 80:20 to 20:80 and all the copolymers were terminated with reactive amino groups, and then were fully characterized through (1H and 13C)-NMR and MALDI-TOF MS anal. to confirm their chem. structures and chem. compns. End chains were revealed by these techniques. Contrary to chlorine-ended copolymers, oligomers terminated with hydroxyl groups were revealed in the amine-ended copolymers, indicating that transetherification reactions occur during the capping reaction with m-aminophenol. Cycles were also revealed by MALDI-TOF MS, that revealed also some unexpected end chains may be formed for the impurities in the feed. The glass transition temps. of the copolymers have been detd. by differential scanning calorimetry (DSC).


324) Characterization of synthetic polymers by MALDI-MS

G.Montaudo, F.Samperi, M.S.Montaudo

Progress in Polymer Science   31,  277-357  - 2006

In recent years, matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectroscopy has become a routine analytical tool for the structural analysis of polymers, complementing NMR and other traditional techniques, a noteworthy change with respect to the past, when mass spectrometry (MS) was seldom used. In this review, we discuss salient aspects of MALDI. First, we devote a section to fundamentals and practice in MALDI of polymers (such as the laser, ion source, ion optics, reflectron, detector, ionization efficiency) as well as to some basic concepts of sample preparation (such as the MALDI matrix and cationization agents). Then, we focus on measurable quantities of polymers: average molar masses, the chemical formula and the structure of the monomer (actually of the repeat unit), the masses of the chain end groups, etc. In-depth coverage is given of coupling MALDI with liquid chromatography (LC), since often LC offers valuable help in exploring macromolecules. The final section is devoted to recent applications, with a detailed discussion of MALDI of addition polymers, condensation polymers, polymers with heteroatoms in the chain, copolymers and partially degraded polymers.


325) Structural elucidation of the core-lipid A backbone from the lipopolysaccharide of Acinetobacter radioresistens S13, an organic solvent tolerant Gram-negative bacterium

S.Leone, A.Molinaro, E.Pessione, R.Mazzoli, C.Giunta, L.Sturiale, D.Garozzo, R.Lanzetta, M.Parrilli

Carbohydrate Research  341,  582-590  - 2006

The structure of the core oligosaccharide of the lipopolysaccharide from an organic solvent tolerant Gram-negative bacterium, Acinetobacter radioresistens S13, was investigated by chemical analysis, NMR spectroscopy and MALDI-TOF mass spectrometry. All the experiments were performed on the oligosaccharides obtained either by alkaline degradation or mild acid hydrolysis. The data showed the presence of two novel oligosaccharide molecules containing a trisaccharide of 3-deoxy-D-manno- octulopyranosonic acid in the inner core region and a glucose rich outer core whose structure is the following:

structure

R = H in the main oligosaccharide and β-Glc in the minor product. The bacterium was grown on aromatic (phenol and benzoic acid) and nonaromatic carbon sources and the core oligosaccharide resulted to occur always with this novel structure.


326) Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with size-exclusion chromatographic fractionation for structural characterization of synthetic aliphatic copolyesters

G.Adamus, P.Rizzarelli, M.S.Montaudo, M.Kowalczuk, G.Montaudo

Rapid Communications in Mass Spectrometry  20(5),  804-814  - 2006

We report matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and off-line coupling of size-exclusion chromatography with MALDI-TOFMS analysis (SEC/MALDI-TOFMS) methods for the detailed characterization of poly[(R,S)-3-hydroxybutyrate-co-L-lactic acid], P[(R,S)-3HB-co-LA], and poly[(R,S)-3-hydroxybutyrate-co-ε- -caprolactone], P[(R,S)-3HB-co-CL], copolymer samples which are expected to be used in special medical application as scaffolds for cartilage and soft tissue engineering. The novel copolyesters contained randomly distributed (R,S)-3-hydroxybutyrate structural units, were synthesized by transesterification of the corresponding homopolymers, i.e. atactic poly[(R,S)-3-hydroxybutyrate], a-PHB, and poly(L-Lactide) (PLLA) or poly(ε-caprolactone) (PCL), respectively. The MS methods used for the characterization of the resulting polydisperse copolyester samples were supported by classical methods (NMR, SEC). The structures of individual copolyester macromolecules, including end-group chemical structures, were established using initially MALDI-TOFMS and then SEC/MALDI-TOFMS. The compositions of the copolyesters were determined by two methods, namely based on 1H NMR and MALDI-TOF spectra. The two sets of values showed good agreement. The sequence distribution was determined using the signal intensities of individual copolyester macromolecules, which appeared in MALDI-TOF mass spectra. Furthermore, sequence analysis gave information about the degree of transesterification. The copolyesters synthesized, with only one exception, were demonstrated to be almost random, which implies that the ester-ester exchange was close to completion.


327) Optical pH Meter by Means of a Porphyrin Monolayer Covalently Assembled on a Molecularly Engineered Silica Surface

A.Gulino, P.Mineo, S.Bazzano, D.Vitalini, I.Fragala

Chemistry of Materials   17(16),  4043  - 2005



328) Redox-active dirhodium(ii,ii) species covalently entrapped into a methylmethacrylate backbone

S.Lo Schiavo, P.Mineo, G.Tresoldi, P.Cardiano, P.Piraino

Dalton Transactions   18,  2979  - 2005

A novel class of polymers was obtained by insertion of dirhodium(ii,ii) metal systems into a methacrylate backbone; the synthesis was realized by free radical polymn. of an appropriate methacrylate-functionalized dirhodium polymer precursor, namely [Rh2(form)2(MA-COO)2] (form = N,N’-di-p-tolylformamidinate) (MA-COO = 2-(methacroyloxy)ethyl-phthalate), with methylmethacrylate (MMA); the new copolymers, in soln., show reversible CO-absorption, connected to the axial reactivity of dirhodium(ii,ii) species


329) Proteomics of gluten: mapping of the 1Bx7 glutenin subunit in Chinese Spring cultivar by matrix-assisted laser desorption/ionization

G.Alberghina, R.Cozzolino, S.Fisichella, D.Garozzo, A.Savarino

Rapid Communications in Mass Spectrometry  19(14),  2069  - 2005

The verification of the cDNA-deduced sequence of the high molecular weight glutenin subunit 1Bx7 in Chinese Spring cultivar was achieved by direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) analysis of the tryptic fragments. The published sequence of the 1Bx7 subunit contains 5 Lys and 15 Arg residues but, due to the presence of three Arg-Pro bonds, which are generally resistant to cleavage by trypsin, or cleaved to a very limited extent by trypsin, 19 peptides can be predicted. The identification of the tryptic fragments was achieved by direct MALDI-MS analysis by using three different matrices (DHB, SA and HCCA) in combination with the most compatible sample preparation procedures in order to obtain the maximum sequence coverage. MALDI analysis of the 1Bx7 tryptic digest resulted in the identification of the expected peptides and additional fragments arising from non-specific cleavages; the fragments that were not detected are peptides with low mass (from 147.2 to 317.4), so we obtained a sequence coverage of 98.8%. The results reported here also indicated that the sequence of the 1Bx7 subunit from cv. Chinese Spring is different from the cDNA-deduced sequence reported in the literature; in particular, a possible insertion of the hexapeptide QPGQGQ within the sequence Gln630-Tyr725 was suggested. Finally, it is possible to rule out glycosylation of the 1Bx7 subunit, or any other post-translational modification, to within the detection limits of the method.


330) New conditions for matrix-assisted laser desorption/ionization mass spectrometry of native bacterial R-type lipopolysaccharides

L.Sturiale, D.Garozzo, A.Silipo, R.Lanzetta, M.Parrilli, A.Molinaro

Rapid Communications in Mass Spectrometry  19(13),  1829  - 2005

A new sample preparation method for matrix-assisted laser desorption/ionization (MALDI) analysis of native rough-type lipopolysaccharides (R-type LPSs) is presented. In our MALDI mass spectra, besides the [M-H]- ions, abundant ions originating from the cleavage between the 3- deoxy-D-manno-oct-2-ulosonic acid (Kdo) unit and the lipid A moiety are always present, giving important pieces of information about the structure of the molecules analyzed. Remarkably, in most cases, the comparison of the MALDI mass spectra of the intact R-type LPS with the Odeacylated one allowed us to obtain the structure of the lipid A moiety.


331) Complete Structural Elucidation of a Novel Lipooligosaccharide from the Outer Membrane of the Marine Bacterium Shewanella pacifica

A.Silipo, S.Leone, A.Molinaro, L.Sturiale, D.Garozzo, E.L.Nazarenko, R.P.Gorshkova, E.P.Ivanova, R.Lanzetta, M.Parrilli

European Journal of Organic Chemistry  2005(11),  2281  - 2005

Shewanella pacifica is a Gram-negative microrganism that is able to grow in sea water. A novel lipooligosaccharide (LOS) has been isolated from the outer membrane of this bacterium and its primary structure fully characterised. For the first time, the presence of a 2,3-dihydroxypropanoic acid residue (glyceric acid) has been identified in the core region. The complete structure of the LOS was determined by compositional and methylation analyses, by MALDI mass spectrometry, and by 1H, 13C and 31P NMR spectroscopy on the oligosaccharides formed by selective degradation of the LOS. Strong alkaline treatment, aimed at recovering and identifying the complete carbohydrate backbone, was carried out by hydrazinolysis followed by de-N-acylation with hot KOH, whereas mild hydrazinolysis (de-O-acylation) allowed us to gain information about the nature of the phosphate and other non-carbohydrate substituents on the core oligosaccharide. Mild acid hydrolysis was employed to obtain a lipid A moiety with which further degradation and mass spectrometry experiments were carried out in order to determine its primary structure.


332) The complete structure of the core carbohydrate backbone from the LPS of marine halophilic bacterium Pseudoalteromonas carrageenovora type strain IAM 12662T

A.Silipo, R.Lanzetta, M.Parrilli, L.Sturiale, D.Garozzo, E.L.Nazarenko, R.P.Gorshkova, E.P.Ivanovac, A.Molinaro

Carbohydrate Research  340(8),  1475  - 2005

The complete novel structure of the components of the core oligosaccharide fraction from the LOS of the halophilic marine bacterium Pseudoalteromonas carrageenovora was characterized. The fully de-acylated lipooligosaccharide was studied by means of compositional analysis, matrix-assisted laser desorption/ionization mass spectrometry and complete 1H and 13C and 31P NMR spectroscopy. The core oligosaccharide is composed by a mixture of species differing for the length of the sugar chain and the phosphorylation pattern:

All sugars are D-pyranoses. Hep is L-glycero-D-manno-heptose, Kdo is 3-deoxy-D-manno-oct-2-ulosonic acid, P is phosphate, residues and substituents in italic are not stoichiometrically linked.


333) Characterization, Optical Recognition Behavior, Sensitivity, and Selectivity of Silica Surfaces Functionalized with a Porphyrin Monolayer

A.Gulino, S.Bazzano, P.Mineo, E.Scamporrino, D.Vitalini, I.Fragala

Chemistry of Materials   17(3),  521  - 2005

The optical gas recognition capability of a covalently self-assembled monolayer of 5,10,15-tri-{p-dodecanoxyphenyl}-20-(p-hydroxyphenyl) porphyrin mols. on silica substrates was studied. The following analytes have been investigated: NO2, CO, CH4, H2, NH3, HCl, CHCl3, C2H5OH, CH3OH, pyridine, tetrahydrofurane, triethylamine, and DMF. The self-assembled porphyrin monolayer appears highly sensitive to 1 ppm of NO2 in both anhyd. and humid conditions. The selectivity of the self-assembled porphyrin monolayer with respect to other analytes was also examd. and present data show that the presence of CO, CH4, H2, and NH3 does not influence its UV-vis spectrum. Many common solvents slowly affect the position of the Soret band. The presence of HCl vapors results in a broad band extending over the entire 440-500 nm range while the starting Soret disappears. UV-vis measurements on a n-hexane 1.0×10-5 soln. of the 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine, that does not contain Ph substituents in the meso positions, show no changes in the optical spectrum upon NO2 interaction. It emerges that arom. substituents in the meso positions play a crucial role in detg. the optical sensing properties.


334) Engineered Silica Surfaces with an Assembled C60 Fullerene Monolayer

A.Gulino, S.Bazzano, G.G.Condorelli, S.Giuffrida, P.Mineo, C.Satriano, E.Scamporrino, G.Ventimiglia, D.Vitalini, I.Fragala

Chemistry of Materials   17(5),  1079  - 2005

A covalently assembled monolayer of 61-(p-hydroxyphenylmethano)fullerene [C60] mols. was synthesized. Both static and dynamic contact angle measurements show that the hydrophobic character increases upon the fullerene linkage. At. force microscopy lithog. shows that the depth of the monolayer is .apprx.19 .ANG.. UV-visible spectra are well-tuned with the presence of the fullerene on the SiO2 surfaces. The surface at. compn., studied by angle-resolved x-ray photoelectron spectra, shows a monotonic increase of the C signal upon decreasing the photoelectron takeoff angles, thus confirming the upper layer nature of this signal. Room-temp. photoluminescence spectra, under controlled atm., show that the oxygen presence influences considerably the luminescence quantum yield.


335) Interactions between water soluble porphyrin-based star polymer and amino acids: Spectroscopic evidence of molecular binding

N.Angelini, N.Micali, V.Villari, P.Mineo, D.Vitalini, E.Scamporrino

Physical Review E  71,  21915  - 2005

Mol. interactions giving rise to stable complexes between an uncharged water sol. cobalt-porphyrin and amino acids are investigated by time-resolved fluorescence, uv-vis, and CD measurements. This metalloporphyrin seems to act, by means of the coordination site of the cobalt of the core, as a recognition host, preferentially, with amino acids possessing arom. groups. The binding with aliph. amino acids requires longer time scales to be efficient and likely involves a slow kinetic process. The exptl. findings suggest that, besides the metal(host)-N(guest) coordination bond, which is the common requisite for all amino acids, a preferential interaction with arom. groups exists there. The soly. in water of the mol., guaranteed by the polyethylene glycol arms as peripheral substituents, in the absence of elec. charges, allows for a more selective discrimination of the binding process with respect to other water-sol. charged porphyrins. The interest devoted to the porphyrin-based star polymer and its recognition properties is, therefore, founded on the potential use either in polymeric matrixes for material science or in aq. soln. for bioscience.


336) Structure of the exopolysaccharide produced by Enterobacter amnigenus

P.Cescutti, A.Kallioinen, G.Impallomeni, R.Toffanin, P.Pollesello, M.Leisola, T.Eerikaeinen

Carbohydrate Research   340(3),  439  - 2005

The bacterial sp. E. amnigenus was isolated from sugar beets harvested in Finland. It produced an exopolysaccharide rich in -fucose, which gave viscous water solns. Its primary structure was detd. Mainly by NMR spectroscopy and ESIMS of oligosaccharides and a polysaccharide with decreased mol. Wt., obtained by Smith degrdn. Of the O-deacetylated native polymer.



337) Current trends in matrix-assisted laser desorption/ionization of polymeric materials

G.Montaudo, F.Samperi, M.S.Montaudo, S.Carroccio, C.Puglisi

European Journal of Mass Spectrometry  11(1),  1  - 2005

In the last few years, mass spectrometry has rapidly become indispensable in polymer analysis and complements in many ways the structural data provided by nuclear magnetic resonance. Mass spectrometry of polymers is emerging as a revolutionary technique, capable of challenging the techniques and protocols established for years for the characterization of synthetic polymers. Matrix-assisted laser desorption/ionization (MALDI) has become a widely applied method for the structural characterization of synthetic polymers. The primary aim of this review is to illustrate some recent advances in the study of macromolecular systems by MALDI. MALDI allows the identification of repeat units and end groups, the structural analysis of linear and cyclic oligomers and the estimate of composition and sequence for copolymers. MALDI is also quite useful for the measurement of molar mass and bivariate distributions in polymers and for the detection of self-association in macromolecules, performed by coupling MALDI and size exclusion chromatography (SEC). Recently MALDI has been applied with remarkable success to the study of thermal and oxidative processes in polymers and to the characterization of copolymers obtained by reactive polymer blending. Selected applications of MALDI to polymers are illustrated herewith.


338) Synthesis and characterization of poly(amidoamine)-platinum(II) complexes. Detailed speciation by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

A.Mazzaglia, L.Monsù Scolaro, D.Garozzo, P.Malvagna, R.Romeo

Journal of Organometallic Chemistry  690(8),  1978  - 2005

MALDI and ESI-MS have been applied to the characterization of the reaction products between the labile cis-[Pt(DMSO)2Cl2] (1) and trans-[Pt(DMSO)2Cl(CH3)] (2) complexes with the simplest poly(amidoamine) ligand (PAMAM, G = 0, 1,2-diaminoethane as core). The comparison of the mass spectra of the starting G0 and those of the metallo-dendrimers formed upon mixing of the reagents in an equimolecular ratio, and the analysis of the isotopic distribution in the ESI spectra, have revealed the formation of cationic and neutral mononuclear complexes with PAMAM as ligand, e.g., cis-[Pt(DMSO)(PAMAM)Cl]Cl or trans- (C,N)[Pt(DMSO)(PAMAM)Cl(CH3)], together with various minor components, which have been identified as derivatives from defective structures of PAMAM. The geometry of the main products has been deduced from the values of the protons coupling constants with the isotopically abundant 195Pt. The metal-to-ligand bond is restricted to the peripheral amino groups of PAMAM which shows sufficient flexibility to involve either one or two branches in the coordination bonding.


339) Microbiological indicators for aquaculture impact in Mar Piccolo (Taranto, Italy)

R.Zaccone, M.Mancuso, A.Modica, D.Zampino

Aquaculture International  13(1-2),  167  - 2005

The mussel and fish-farming impact was investigated both in pelagic and sediment environments of Mar Piccolo in Taranto. We studied the yearly distribution of microbiological indicators (heterotrophic bacteria and coliforms), in relation to physical and chemical parameters of surface water at three different sites, characterized by mussel farms, fish cages and Citro springs. The heterotrophic bacteria and Clostridium perfrigens distribution were also examined in relation to organic content and granulometry of sediments. The urban sewages affected the quality of waters of the mussel site, by increasing faecal coliforms in the entire basin during summer. In the benthonic environment the aquaculture activity increased the bio-deposition of the sediment, causing changes in the abundance and the composition (heterotrophic bacteria/clostridia ratio) of microflora. A significant increase of heterotrophic bacteria in the warm season was observed. The clostridia proved to be a good indicator of impact of organic matter because they were significantly higher in the sites than the control stations.


340) An x-ray photoelectron spectra and atomic force microscopy characterization of silica substrates engineered with a covalently assembled siloxane monolayer

A.Gulino, G.G.Condorelli, P.Mineo, I.Fragalà

Nanotechnology  16,  2170  - 2005

Silica substrates were functionalized with a covalent 4-ClCH2C6H4SiCl3 monolayer. Additional covalent bonding of appropriate functional molecules to the silylated substrates was further achieved. The surface chemical characterization was carried out by angle resolved x-ray photoelectron measurements. Moreover, surface morphological characterizations were performed by atomic force microscopy measurements. Present results provide step by step information on the covalently linked monolayer during the synthetic procedure.


341) Hypoglycosylation with increased fucosylation and branching of serum transferrin N-glycans in untreated galactosemia

L.Sturiale, R.Barone, A.Fiumara, M.Perez, M.Zaffanello, G.Sorge, L.Pavone, S.Tortorelli, J.F.O’Brien, J.Jaeken, D.Garozzo

Glycobiology  15,  1268  - 2005

Untreated classic galactosemia (galactose-1-phosphate uridyltransferase [GALT] deficiency) is known as a secondary congenital disorders of glycosylation (CDG) characterized by galactose deficiency of glycoproteins and glycolipids (processing defect or CDG-II). The mechanism of this undergalactosylation has not been established. Here we show that in untreated galactosemia, there is also a partial deficiency of whole glycans of serum transferrin associated with increased fucosylation and branching as seen in genetic glycosylation assembly defects (CDG-I). Thus galactosemia seems to be a secondary "dual" CDG causing a processing as well as an assembly N-glycosylation defect. We also demonstrated that in galactosemia patients, transferrin N-glycan biosynthesis is restored upon dietary treatment.


342) Effect of delay time and grid voltage changes on the average molecular mass of polydisperse polymers and polymeric blends determined by delayed extraction matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

P.Mineo, D.Vitalini, E.Scamporrino, S.Bazzano, R.Alicata

Rapid Communications in Mass Spectrometry  19(19),  2773  - 2005

The dependence of the calcd. av. mol. mass of a polyethylene glycol with a large polydispersity on the instrumental parameters adopted in the acquisition of mass spectra using delayed extn. matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (DE MALDI-TOFMS) was investigated. It has been shown that a combined effect of delay times and potential gradients can act on the ion cloud in the source chamber affecting both mass resoln. and av. mol. mass value of the analyzed polymeric sample. Also examd. was a blend of two different polymers (a PEG and a PMMA com. sample having a similar av. mol. mass), which presents an addnl. problem concerning the discrimination among the different polymer species as a function of the exptl. conditions. In this work, the best instrumental conditions to obtain both good resoln. and a correct av. mol. mass for the examd. polydisperse sample are reported.


343) Uncharged Water-Soluble Co(II)-Porphyrin: A Receptor for Aromatic á-Amino Acids

N.Angelini, N.Micali, P.Mineo, E.Scamporrino, V.Villari, D.Vitalini

Journal of Physical Chemistry B   109(39),  18645  - 2005

Changes in the UV-vis spectra and induced CD (ICD) signals obsd., in correspondence with the porphyrin Soret region, for aq. solns. of achiral 5,10,15,20-tetrakis{p-[ω-methoxy poly(oxy-ethylene)]phenyl}porphyrin cobalt (II) (Co-P) and arom. α-L-amino acids (Trp and Phe) give direct evidence for the coordination between the Co-P and amino acids. Considering that Co-P, besides the Co atom (one-fixation-point system), does not contain in the mol. active ligand groups and that no ICD signals have been obsd. in the case of Co-P/Ala, it has been concluded that hydrophobic interactions or stacking interactions between the arom. rings of the porphyrin and those of Trp or Phe, acting as further amino acid (AA) fixation points, can strongly reduce the mobility of the chiral guest, thus permitting the generation of ICD signals. The effects of changes of both pH (in the range 2-9) and amino acid structure on the ICD phenomenon have also been investigated. In particular, the following have been obsd.: (i) strong ICD signals for all of the Co-P/N-acetyl amino acid aq. solns. at pH 7, (ii) an unexpected ICD band with a bisignate form for the Co-P/Ala soln. at pH 9 after long aging, and (iii) an opposite ICD signal when α-D-Phe and α-D-Trp enantiomers have been used. The data reported in this paper show how the binding mechanism between receptor and AAs changes by modulating properly the pH or the mol. structures and indicate that in these aq. solns. the coordination Co-N is not the fundamental mechanism giving rise to the formation of the complexes and that the binding can be driven by hydrophobic interactions. These occurrences, through the anal. of the spectroscopic response (and, in particular, the form of the ICD band), can allow the recognition of AAs.


344) Structural characterization of the carbohydrate backbone of the lipooligosaccharide of the marine bacterium Arenibacter certesii strain KMM 3941T

A.Silipo, A.Molinaro, E.L.Nazarenko, L.Sturiale, D.Garozzo, R.P.Gorshkova, O.I.Nedashkovskaya, R.Lanzetta, M.Parrilli

Carbohydrate Research  340(16),  2540  - 2005

The structure of the carbohydrate backbone of the lipooligosaccharide (LOS) of the marine bacterium Arenibacter certesii strain KMM 3941T has been elucidated. The structure was obtained by means of compositional analysis, matrix-assisted laser desorption/ionization mass spectrometry and complete 1H and 13C and 31P NMR spectroscopy. It shows novel and interesting aspects and is the first description of Arenibacter lipopolysaccharides. Strong and mild alkaline treatments, to fully deacylate and only to O-deacylate the LOS were performed in order to determine the core structure. The core consists of a mixture of species differing by the presence of a non-stoichiometric α-D-rhamnose residue. The Kdo unit is substituted at O-5 by α-mannose and at O-4 by a α-galactosyluronic acid phosphate. The lipid A is constituted by a bis-phosphorylated disaccharide unit composed by a 2,3- diamino-2,3-dideoxy-β-D-glucopyranose (DAG) residue as non-reducing end and a GlcN as reducing end.



345) The Elicitation of Plant Innate Immunity by Lipooligosaccharide of Xanthomonas campestris

A.Silipo, A.Molinaro, L.Sturiale, J.M.Dow, G.Erbs, R.Lanzetta, M.A.Newman, M.Parrilli

Journal of Biological Chemistry  280(39),  33660  - 2005

Lipopolysaccharides (LPSs) and lipooligosaccharides (LOSs) are major components of the cell surface of Gram-negative bacteria with diverse roles in bacterial pathogenesis of animals and plants that include elicitation of host defenses. Little is known about the mechanisms of perception of these molecules by plants and about the associated signal transduction pathways that trigger plant immunity. Here we address the issue of the molecular basis of elicitation of plant defenses through the structural determination of the LOS of the plant pathogen Xanthomonas campestris pv. campestris strain 8004 and examination of the effects of LOS and fragments obtained by chemical treatments on the immune response in Arabidopsis thaliana. The structure shows a strong accumulation of negatively charged groups in the lipid A-inner core region and has a number of novel features, including a galacturonyl phosphate attached at a 3-deoxy-D-manno-oct-2-ulosonic acid residue and a unique phosphoramide group in the inner core region. Intact LOS and the lipid A and core oligosaccharides derived from it were all able to induce the defense-related genes PR1 and PR2 in Arabidopsis and to prevent the hypersensitive response caused by avirulent bacteria. Although LOS induced defense-related gene transcription in two temporal phases, the core oligosaccharide induced only the earlier phase, and lipid A induced only the later phase. These findings suggest that plant cells can recognize lipid A and core oligosaccharide structures within LOS to trigger defensive cellular responses and that this may occur via two distinct recognition events.


346) A calix[5]arene-based heterotetratopic host for molecular recognition of long-chain, ion-paired á,ù-alkanediyldiammonium salts

D.Garozzo, G.Gattuso, A.Notti, A.Pappalardo, S.Pappalardo, M.F.Parisi, M.Perez, I.Pisagatti

Angewandte Chemie-International Edition  44(31),  4892  - 2005

The anions went in two by two: Sep. ion-pair binding of nano-sized α,ω-alkanediyldiammonium dichloride salts is achieved in org. media with high efficiency and selectivity by a heterotetratopic receptor that comprises two converging calix[5]arene units to tightly encapsulate the linear dication, as well as two ureido side functions to simultaneously bind the chloride counteranions through hydrogen bonding.


347) Mass spectrometric strategies for the N-glycosylation analisys of serum glycoproteins in patients with congenital disorders of glycosylation (CDG) and galactosemia

L.Sturiale, R.Barone, M.Perez, G.Sorge, J.Jaeken, D.Garozzo

Glycoconjugate Journal  22 (4/5/6) ,  202  - 2005

Congenital disorders of glycosylation (CDG) and galactosemia are inherited metabolic diseases which have in common the occurrence of an abnormal glycosylation pattern of some serum glycoproteins. CDG are due to defects in the synthesis of N-glycans and less frequently affect the O-glycosylation pathway. As glycoproteins are ubiquitous molecules, CDG present as multisystemic disorders with a prominent central nervous system involvement and a variable clinical spectrum. CDG type I defines defects owing to impaired synthesis of the lipid-linked oligosaccharide and/or its transfer to the nascent glycoprotein in the cytosol and in the endoplasmic reticulum, CDG type II refers to abnormalities in the glycoprotein processing at the Golgi level. The most common form of galactosemia, due to a deficiency of galactose-1-phosphate uridyltransferase (GalT), causes accumulation of galactose and galactose-1-phosphate in blood and tissues, and if untreated, produces severe symptoms as mental retardation, cirrhosis of the liver, and cataracts. In both CDG and galactosemia an abnormal glycosylation pattern involving multiple serum glycoproteins may be promptly detectable by the isoelectric focusing (IEF) of serum proteins following by immunodetection of transferrin isoforms which show a cathodal shift due to the absence of terminal negatively charged sialic acid residues. Although IEF allows the measurements of the sialylation degree in serum transferrin, it is uninformative about the presence of isoforms due to the partial occupancy of one or both transferrin glycosylation sites and the detailed analysis of the N-glycan structures. In order to identify glycosylation abnormalities both in CDG and in galactosemia patients, additional techniques such as matrix assisted laser-desorption ionisation (MALDI) and Electrospray mass spectrometry may be essential. We used mass spectrometry based strategy to define the glycosylation degree of intact glycoproteins and to detect changes in serum protein N-glycan profiles. These findings open the way to a better understanding of the biochemical mechanisms of defective glycosylation.


348) Sequence determination in aliphatic poly(ester amide)s by matrix-assisted laser desorption/ionization time-of-flight and time-of-flight/time-of-flight tandem mass spectrometry

P.Rizzarelli, C.Puglisi, G.Montaudo

Rapid Communications in Mass Spectrometry   19(17),  2407  - 2005

Poly(ester amide)s from dimethyl sebacate or sebacic acid and 2-aminoethanol or 4-amino-1-butanol were characterized by post-source decay matrix-assisted laser desorption/ionization time-of-flight (PSD-MALDI-TOF) and time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS/MS). Sodiated oligomers were selected as precursor ions for dissociation studies. PSD analysis was performed on dimethyl sebacate, dicarboxylic, carboxylic and amino alcohol, and diamino alcohol terminated oligomers. PSD-MALDI-TOF mass spectra yielded information on the fragmentation mechanisms of the poly(ester amide) chains, showing that the main cleavages proceed through a beta-hydrogen transfer rearrangement. MALDI-TOF/TOF-MS/MS provided structural information concerning ester/amide sequences in the polymer chains. As expected, together with the ions appearing in the PSD-MALDI mass spectrum, several new abundant fragment ions in the low-mass range are present in MALDI-TOF/TOF-MS/MS spectra. These new product ions proved to be diagnostic and made it possible to establish the presence of random sequences of ester and amide bonds in the poly(ester amide)s samples.


349) New Vistas in Polymer Degradation. Thermal Oxidation Processes in Poly(ether imide)

S.Carroccio, C.Puglisi, G.Montaudo

Macromolecules  38(16),  6849  - 2005

Poly{2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride-1,3-phenylendiamine} copolymer (ULTEM) was subjected to thermoaging in an attempt to det. the structure of the species formed during oxidative degrdn. The oxidative process was followed as a function of exposure time by using MALDI-TOF MS. Thermal oxidn. produces charring after only 15 min and the formation of insol. residue amts. to 50% after 180 min at 350°C. Highly valuable structural information (including the end groups) was extd. from the MALDI spectra of the thermally oxidized ULTEM sol. samples. Oxidized specimens contained acetophenone, phenylacetic acid, phenols, benzoic acid, bisphenol A, phthalimide, and phthalic anhydride end groups. The mechanisms accounting for their formation involve several reactions: (i) cleavage of the di-Ph ether units; (ii) oxidative degrdn. of the isopropylidene bridge of BPA units; (iii) thermal cleavage of phenylphthalimide units.


350) Comparison of Photooxidation and Thermal Oxidation Processes in Poly(ether imide)

S.Carroccio, C.Puglisi, G.Montaudo

Macromolecules  38(16),  6863  - 2005

Thermal oxidn. and photooxidn. processes occurring in poly 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride-1,3-phenylendiamine copolymer (ULTEM), were investigated and compared. The study aimed at finding possible differences in the oxidn. pathways of this complex polymer by using the anal. power of MALDI techniques. ULTEM films were subjected to photooxidn. by exposure at 60 °C in a UV accelerated chamber (Q-UV Panel) in atm. air, and the oxidative process was followed as a function of the exposure time. Relevant structural information on the photooxidized ULTEM species was extd. from the MALDI spectra. These data show the presence of polymer chains contg. acetophenone, Ph acetic acid, phenols, benzoic acid, phthalic anhydride, and phthalic acid end groups. The mechanisms accounting for the formation of photooxidn. products of Ultem involve several reactions: (i) photocleavage of Me groups of the N-Me phthalimide terminal units; (ii) photooxidative degrdn. of the isopropylidene bridge of BPA units; (iii) photooxidn. of phthalimide units to phthalic anhydride and phthalic acid end groups. Some of these cleavage pathways are specific for the photooxidn. process and the oligomers deriving from them are absent in the thermal by oxidized Ultem samples, whereas the thermal cleavage of the di-Ph ether units appears to occur only in the thermal oxidn. process.


351) Deep-chlorophyll maximum time series in the Augusta Gulf (Ionian Sea): Microbial community structures and functions

R.Zaccone, C.Caroppo, R.La Ferla, D.Zampino, G.Caruso, M.Leonardi, G.Maimone, M.Azzaro, R.Sitran

Chemistry and Ecology  20,  267-284  - 2004

DOI: https://doi.org/10.1080/02757540410001689812
An integrated study was carried out to follow the temporal evolution of microbiological parameters during a 48 h period, in relation to the deep chlorophyll maximum (DCM) at a coastal station. The micro-organisms showed an active role in the environment and a different distribution, without a clear diel cycle. The phytoplankton community, responsible for the DCM, consisted mainly of diatoms. Their distribution in relation to pycnocline showed an opposite trend with respect to picophytoplankton. Total bacterioplankton contributed to enzymatic degradation of particulated organic carbon (by producing β-glucosidase and aminopeptidase), with peaks related to changes in the main water current. We estimated that about 25% of particulate organic carbon per day may be hydrolysed by bacteria. The living bacterioplankton represented 20% of the total. The picophytoplankton fraction contributed significantly to the high values of alkaline phosphatase, suggesting a fast P regeneration. Respiration showed significant correlations with the physical and chemical parameters as well as with the different planktonic fractions.


352) Determination of living and active bacterioplankton: a comparison of methods

D.Zampino, R.Zaccone, R.La Ferla

Chemistry and Ecology  20,  411-422  - 2004

DOI: https://doi.org/10.1080/02757540410001728007
The purpose of this study was the quantification, through the comparison of different methods, of viable and metabolically active bacteria in marine environments. To quantify the living and active bacterioplankton fractions, we compared the total cell count (TC using DAPI staining), plate count on marine agar (CFU), and three viability-staining methods: nucleoid-containing cell count (NuCC), Live/Dead staining procedure (L/D) and direct viable count (DVC). With respect to TC (mean value 3.0 ± 2.3 × 105 cell ml-1) CFU represented less than 0.1% and DVC cells 1%, both showing significant differences. NuCC and L/D cells were 18.0% and 15.9% of TC, respectively, showing no significant differences and higher percentages in the Ionian Sea than the Adriatic Sea. Moreover, NuCC and L/D were two orders of magnitude greater than the culturable fraction, while active cells (DVC) exceeded CFU by one order of magnitude. The comparison of different staining methods allowed us to confirm the simultaneous presence of different physiological states within the bacterial population in natural marine environments. The NuCC and L/D methods gave comparable values to those of other authors, while the DVC procedure gave lower values than previously reported. This research provides information on the fraction of living and/or metabolically active bacteria in aquatic ecosystems. Since each method has its own detection limits, the study highlights the need to simultaneously compare the different methods to validate their results.


353) Densities, Viscosities, and Refractive Indices of New Mixtures of Poly(ethylene glycols) + Dialkyl Carbonates at 313.15 K

S.Ottani, D.Vitalini, F.Comelli, C.Castellari

Journal of Chemical & Engineering Data  49(1),  148  - 2004

Densities, viscosities, and refractive indexes for binary systems contg. mixts. of poly(ethylene glycols) at the same no.-av. mol. mass (Mn » 300) but different polydispersities (mol. mass distribution between 1.15 and 1.98) with di-Me carbonate or di-Et carbonate were detd. at 313.15 K and at atm. pressure. The measurements were carried out over the whole range of compn., using a vibrating-tube d. meter, Ubbelohde viscometers with a Schott-Geraete AVS 310 unit, and an Abbe refractometer. Densities, viscosities, and refractive indexes were used to compute the excess vols., VE, viscosity deviations, Δ η, and deviations in molar refraction, ΔR. Results were fitted to the Redlich-Kister polynomial, and the adjustable parameters were obtained using least-squares methods. The viscosity dependence on temp. was investigated between (309.15 and 327.15) K for some solns. in a restricted compn. range. A qual. discussion on these quantities in terms of mol. interactions is reported.


354) Coordination features of difunctionalized â-cyclodextrins with carnosine: ESI-MS and spectroscopic investigations on 6A,6D-di-(â-alanyl-L-histidine)-6A,6D-dideoxy-â-cyclodextrin and 6A,6C-di-(â-alanyl-L-histidine)-6A,6C-dideoxy-â-cyclodextrin and their copper(II) complexes

P.Mineo, D.Vitalini, D.La Mendola, E.Rizzarelli, E.Scamporrino, G.Vecchio

Journal of Inorganic Biochemistry  98(2),  254  - 2004

The synthesis and characterization of two β-cyclodextrins (β-CD) functionalized with two units of carnosine (β-alanyl-l-histidine) through the amino group, 6A,6C-(β-alanyl-L-histidine)-6A,6C-dideoxy-β-cyclodextrin (ACCDAH) and 6A,6D-(β-alanyl-L-histidine)-6A,6D-dideoxy-β-cyclodextrin (ADCDAH), are reported. NMR and C.D. data of the ligands indicate a different interaction of dipeptide chains with upper rim and cavity of β-CD. Analogously, spectroscopic and electrospray ionization mass spectrometry data show different copper(II) complex species formed by the two regioisomers. The ability of carnosine-cyclodextrin derivs. to bind copper ions in a head-to-tail fashion induces the formation of oligomeric species (up to hexamers) in the case of ACCDAH, where the two carnosine moieties are adjacent, while in the ADCDAH case the mutual interaction between the peptidic chains of two ADCDAH mols. allows the almost exclusive formation of a copper-assisted self-assembled dimeric species.


355) Effect of excess enthalpies on binary mixtures containing propylene glycols and poly(propylene glycols) + dimethyl carbonate at 308.15 K

C.Castellari, D.Vitalini, F.Comelli, R.Francesconi

Thermochimica Acta  412(1-2),  125  - 2004

Excess enthalpies have been detd. at atm. pressure and at 308.15 K over the entire range of compn. for binary mixts. contg. propylene glycol (PG), dipropylene glycol (DPG), tripropylene glycol (TPG), poly(propylene glycol)-400, -725, -1200, -2000 + di-Me carbonate (DMC). From the experimetal data, excess enthalpies, HE, and std. deviations in enthalpy, s(HE) have been calcd. The exptl. data were fitted to a Redlich-Kister polynomial to obtain the binary adjustable parameters, ak. The HE values are pos. over the entire range of compn., decreasing with the increase of the mol. wt. of glycols. The mixts. contg. polydisperse glycols behave as regular solns. Conclusions were qual. discussed in terms of mol. interactions.


356) Thermal degradation of poly(ethylene terephthalate) at the processing temperature

F.Samperi, C.Puglisi, R.Alicata, G.Montaudo

Polymer Degradation and Stability  83(1),  3  - 2004

Several isothermal degrdn. expts. on poly(ethylene terephthalate) (PET) were conducted in the temp. range of 270-370°C in order to simulate reactions that take place during the processing of PET under a nitrogen atm. Structural characterization of the reaction products was performed by MALDI mass spectrometry and by NMR anal. The results indicate the formation of cyclic oligomers that decomp. at higher temp. Vinyl ester-terminated oligomers could not be detected by MALDI or by 1H and 13C NMR, whereas the formation of anhydride-contg. oligomers was noted. Formation of acetaldehyde in PET samples processed at various temps. was detected by 1H NMR. We have also included in the present study a set of expts. where 0.5 wt.% p-toluenesulfonic acid hydrate (I) was added to the polyester. Our results show that the addn. of small amts. of I and heating the compn. at 270 or 285°C induces a strong hydrolytic reaction with consequent increase of carboxy-terminated polyester chains.


357) Thermal degradation of poly(butylene terephthalate) at the processing temperature

F.Samperi, C.Puglisi, R.Alicata, G.Montaudo

Polymer Degradation and Stability  83(1),  11  - 2004

We previously reported an investigation on the isothermal degrdn. of poly(ethylene terephthalate) (PET) and present here a parallel study on poly(butylene terephthalate) (PBT). Although the two polyesters are structurally quite similar, our results show that the presence of the butylene unit in PBT is apparently able to induce significant changes in the isothermal degrdn. of PBT compared to PET. A rationalization of the differences obsd. is offered. Several isothermal degrdn. expts. on PBT were conducted at 270-350°C in order to simulate the reactions that take place in its actual thermal processing of. Structural characterization of the reaction products was performed by MALDI mass spectrometry and by NMR anal. The results indicate that cyclic oligomers of PBT formed at temps. below 290°C by ring-chain equilibration undergo thermal decompn. at higher temps. by a β-hydrogen transfer mechanism, as well as the open PBT chains. The formation of unsatd. oligomers was detected by MALDI and also by 1H and 13C NMR techniques, whereas in contrast to the thermally degraded PET sample, terephthalic anhydride-contg. oligomers were not obsd. Formation of butadiene was suggested by 1H NMR data on PBT samples processed at various temps.


358) Mass spectra of copolymers which display compositional drifts or sequence constraints

M.S.Montaudo

Journal of the American Society for Mass Spectrometry  15(3),  374  - 2004

The spectral features appearing in mass spectra of random and block copolymers which display a drift in compn. are discussed along with features appearing in mass spectra of terpolymers and tetrapolymers with sequence constraints. It is shown that previous models cannot account for these features. A new model is presented and a compact equation is derived which yields MS intensities. The prediction of the model is compared with some literature data, namely mass spectrometric data concerning a block copolymer sample contg. units of α-Me styrene and of methylmethacrylate which display a strong drift in compn., the molar fraction of methylmethacrylate units changing from 0.99 to 0.80 when passing from short to long macromol. chains. The agreement between theory and expt. is good. A hyperbranched polymer obtained by condensing 4,4'-bis[p(acetoxy)phenyl] valeric acid (referred to as diphenolic acid, DPA) was then considered. The polymer turned out to be a copolymer with regular DPA units and modified DPA units (possessing a phenol group). The molar fraction of regular DPA units changes from 0.80 to 0.95 when passing from low masses to high masses. Copolymers with sequence constraints are considered, such as ABC copolymers in which AA cannot be found along the chain or ABCD copolymers in which A cannot follow A, B cannot follow B, etc. The novel method is applied to an exactly alternating copolymer with units of styrene (St) and maleic anhydride (MAH). The St-MAH sample turned out to be a complex mixt. and the presence of a small amt. of units of maleic acid (MAC) is detected. The abundance of MAC, estd. by the chain statistical method, is 5%. The method is applied to the copolymer obtained by reactive blending of poly(butylene terephthalate) and poly(bisphenolA carbonate). In this case, the theor. spectra are generated and spectral features are discussed.


359) Evidence for Selective Hydrolysis of Aliphatic Copolyesters Induced by Lipase Catalysis

P.Rizzarelli, G.Impallomeni, G.Montaudo

Biomacromolecules  5(2),  433  - 2004

DOI: https://pubs.acs.org/doi/10.1021/bm034230s
High molar mass random poly(butylene succinate-co-butylene sebacate), P(BS-co-BSe), and poly(butylene succinate-co-butylene adipate), P(BS-co-BA), with different compn., were synthesized and subjected to enzymic hydrolysis by Lipase from Mucor miehei or from Rhizopus arrhizus. The enzymic hydrolysis of P(BS-co-BSe)s and P(BS-co-BA)s films produced a mixt. of water-sol. monomers and co-oligomers that were sepd. and identified by online high performance liq. chromatog./electrospray ionization mass spectrometry (HPLC/ESI-MS). Optimization of the HPLC anal. allowed the sepn. of isobar co-oligomers, differing only for the co-monomers sequence. Oligomers with the same monomer compn. and molar mass but different sequence were identified by HPLC/ESI-MS-MS online anal. The results obtained show a preferential hydrolytic cleavage induced by the lipases used. In particular, these enzymes prefer cleaving sebacic ester bonds in P(BS-co-BSe) copolymers, whereas succinic ester bonds appear to be hydrolyzed faster than adipic ester bonds in P(BS-co-BA) copolyesters. 1H NMR anal. further substantiates these findings. The primary products generated by lipase hydrolysis of polyester films underwent further degrdn. at longer reaction times. The HPLC/ESI-MS anal. of these mixts. at various times provided the first evidence that lipase catalysis is active also in water soln., a hydrophobic effect induced by the aliph. units of these polyesters.


360) From calixfurans to heterocyclophanes containing isopyrazole units

G.Cafeo, D.Garozzo, F.H.Kohnke, S.Pappalardo, M.F.Parisi, R.Pistone Nascone, D.J.Williams

Tetrahedron  60(8),  1895  - 2004

Cyclic poly-1,4-diketones 2, obtained by the oxidn. of the furan units present in calix[4]furan 1a and calix[6]furan 1c have been converted into the novel heterocyclophanes 4a and 4c contg. four and six isopyrazole units, resp. Soln. studies have demonstrated the ability of 4a and 4c to act as ligands for transition metals. The crystal structures of 4a and the coordination compd. formed by 4c with 2 equiv. of cis-PtCl2(DMSO)2 have been detd. In the solid state 4c is shown to bind arom. substrates within its cavity.


361) New fragmentation mechanisms in matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry of carbohydrates

E.Spina, L.Sturiale, D.Romeo, G.Impallomeni, D.Garozzo, D.Waidelich, M.Glueckmann

Rapid Communications in Mass Spectrometry  18(4),  392  - 2004

The spectra recorded by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS/MS) of complex carbohydrates from human milk are presented. Besides ions originating from glycosidic cleavages and from sugar ring fragmentations, these spectra show intense peaks that may be assigned to ions produced by three new fragmentation pathways involving a six-atom rearrangement. These ions, together with the A fragments from sugar ring fragmentations, open the possibility of obtaining a complete mapping of the linkage positions present in the carbohydrates investigated by MALDI-TOF/TOF.


362) Multivalent binding of galactosylated cyclodextrin vesicles to lectin

A.Mazzaglia, D.Forde, D.Garozzo, P.Malvagna, B.J.Ravoo, R.Darcy

Organic & Biomolecular Chemistry  2(7),  957  - 2004

Amphiphilic β-cyclodextrins with alkylthio chains at the primary-hydroxyl side and galactosylthio-oligo-(ethylene glycol) units at the secondary-hydroxyl side, which form nanoparticles and vesicles, show multivalent effects in their binding to lectin.


363) Recent Advances in MALDI Mass Spectrometry or Polymers

G.Montaudo, S.Carroccio, M.S.Montaudo, C.Puglisi, F.Samperi

Macromolecular Symposia  218(1),  101  - 2004

Matrix-Assisted Laser Desorption/Ionization (MALDI) allows the identification of repeat units and end groups, the structural analysis of linear and cyclic oligomers, and the estimate of composition and sequence far copolymers. MALDI has also been applied to the measurement of molar mass distributions in polymers and to the study of thermal and oxidative processes in polymers. This paper illustrates the detection of self-association in macromolecules made by coupling MALDI and Size Exclusion Chromatography (SEC), the investigation of polymer oxidation phenomena, and the characterization of copolymers formed in the processing of reactive polymer blends.


364) New copoly(bisphenol-A)carbonates, having hydrophilic porphyrin units as end-groups, synthesized by melt-reacting processes

E.Scamporrino, R.Alicata, S.Bazzano, D.Vitalini, P.Mineo

Macromolecular Symposia  218(1),  21  - 2004

The synthesis of some poly(bisphenol-A)carbonates (PCs) contg. hydrophilic porphyrin units as end groups, by thermal treatment of commercial PC and 5,10,15-tri {p[ω-methoxy-poly(oxyethylene)]phenyl}20(p-hydroxy phenyl)porphyrin (1) blends, is reported. A suitable choice of reaction temperature, molar composition and reaction time, allowing the extent of the outer-inner transesterification reactions, leads to a gradual insertion of porphyrin units in the polymer chains. The composition of the obtained materials was inferred by GPC and MALDI-TOF mass spectrometric analysis.


365) Microbial Synthesis of Poly(3-hydroxyalkanoates) by Pseudomonas aeruginosa from Fatty Acids: Identification of Higher Monomer Units and Structural Characterization

T.Barbuzzi, M.Giuffrida, G.Impallomeni, S.Carnazza, A.Ferreri, S.P.P.Guglielmino, A.Ballistreri

Biomacromolecules  5(6),  2469  - 2004

Pseudomonas aeruginosa ATCC 27853 accumulated poly(3-hydroxyalkanoates) (PHAs) after growth on satd. fatty acids with an odd no. of carbon atoms. No nutrient limitation was required to induce PHA synthesis, although better yields were obtained when the medium was magnesium deprived. A comparative study was carried out between PHAs obtained from C-odd and those from C-even carbon sources. Repeating units identification was performed by gas chromatog. (GC) and capillary liq. chromatog.-electrospray mass spectrometry (LC-ESI MS) of methanolyzed samples. When C-odd n-alkanoic acids from nonanoic to pentadecanoic were used the lowest hydroxyalkanoate unit found was 3-hydroxyvalerate and the highest 3-hydroxypentadecanoate, whereas when C-even acids from octanoic to eicosanoic were used these were 3-hydroxycaproate and 3-hydroxyeicosanoate, resp. Wt. av. mol. wts. were in the range 187,000-596,000. DSC traces showed Tm and DHm which varied from 43 to 58 °C and from 5.9 to 24.8 J/g, with the PHAs generated from C-odd carbon sources having lower values. ESI MS of partially pyrolyzed samples allowed the identification of oligomers up to heptamers, and statistical anal. of the ions intensity in the mass spectra showed that these PHAs are random copolyesters.


366) Increased fucosylation and branching of serum transferrin N-glycans in long-term untreated Galactosemic patients

L.Sturiale, R.Barone, G.Sorge, M.Zaffanello, A.Fiumara, G.Impallomeni, D.Garozzo

Glycobiology  14(11),  1154  - 2004

Galactosemia is an autosomal recessive disorder caused, in the most common form, by mutation in the galactose-1-phosphate uridyltransferase (GALT) gene (ch. 9p13). The resulting enzyme deficiency leads to anomalous accumulation of galactose and gatactose-1-phosphate in blood and tissues and produces severe symptoms as mental retardation, cirrhosis of the liver and cataracts, prevented by a galactose-free diet. In untreated galactosemic patients, isoform patterns of serum transferrin, lysosomal enzymes b-hexosaminidase and a-fucosidase and follicle stimulating hormone are abnormal, due to the increase of relatively neutral isoforms corresponding to less sialylated carbohydrate structures [1-2]. These evidences are similar to those observed in the Congenital Disorders of Glycosylation (CDG) which are inherited disorders characterized by a defective synthesis of the carbohydrate moiety of multiple serum glycoproteins. In order to investigate the glycosylation abnormalities in galactosemic patients, we used MALDI mass spectrometry to individuate the glycosylation degree of intact glycoproteins and to achieve the fully characterization of the N-linked oligosaccharide structures. Particularly, we focused on the glycosylation pattern of rivanol purified serum transferrin (the classical biochemical marker of CDGs) in two galactosemia patients before treatment and during follow-up on galactose-free diet. The results were compared with those obtained in subjects with CDG-Ia (PMM deficiency) and healthy controls. The galactosemic patients were both overexposed to dietary galactose (11 and 5 weeks respectively) because of an initial false negative newborn screening following red blood cell transfusion. In long-term untreated galactosemia we found a severe underoccupancy of both transferrin N-glycosylation sites according to the isoelectric focusing pattern and the profile of MALDI-TOF mass spectra of the intact glycoprotein. Release of N-glycans after PNGase F digestion of the same samples, followed by MALDI-TOF analysis both in negative and in positive polarity, revealed a great heterogeneity of glycoforms ranging from truncated biantennary species deprived of sialic acid and/or galactose, to triantennary and tetraantennary species at higher molecular weight. Moreover, we found a significant increase of the fucosylation degree of all the glycoforms, already reported for CDG-I [3], but never observed before in galactosemia. Such abnormal findings were not observed upon dietary treatment. These evidences suggest that in long-term untreated galactosemia, defects in both the assembly as well as in the processing pathways may occur. These findings open the way to a better comprehension of the biochemical mechanisms regarding the defective glycosylation pathway in galactosemia.


367) Structure of minor oligosaccharides from the lipopolysaccharide fraction from Pseudomonas stutzeri OX1

S.Leone, V.Izzo, L.Sturiale, D.Garozzo, R.Lanzetta, M.Parrilli, A.Molinaro, A.Di Donato

Carbohydrate Research   339(16),  2657  - 2004

A minor oligosaccharide fraction was isolated after complete de-acylation of the lipooligosaccharide extracted from Pseudomonas stutzeri OX1. The full structure of this oligosaccharide was obtained by chemical degradation, NMR spectroscopy and MALDI-TOF MS spectrometry. These experiments showed the presence of two novel oligosaccharides (OS1 and OS2):

where R = (S)-Pyr(-->4,6) in OS1 and α-Rha-(1-->3) in OS2. All sugars are D-pyranoses, except Rha, which is L-pyranose. Hep is L-glycero-D-manno-heptose, Kdo is 3-deoxy-D-manno-oct-2-ulosonic acid, Pyr is pyruvic acid, P is phosphate.


368) Structural Determination of the O-Chain Moieties of the Lipopolysaccharide Fraction from Agrobacterium radiobacter DSM 30147

C.De Castro, E.Bedini, D.Garozzo, L.Sturiale, M.Parrilli

European Journal of Organic Chemistry  18,  3842  - 2004

Two O-chain structures were identified after acid hydrolysis of the lipopolysaccharide fraction of Agrobacterium radiobacter (type strain). The first is constituted by the linear tetrasaccharide repeating unit [2)-α-L-Rhap-(1 3)-α-L-Rhap- (1 3)-α-L-Rhap-(1 2)-α-L-Rhap-(1 ]n and the second by the (1 2)-branched repeating unit α-D-Manp-(1 2)-[3)-α-DFucp-( 1 3)-α-D-Fucp-(1 ]n.The two structures were determined mainly by 1D- and 2D NMR spectroscopy together with chemical-degradation methods. A detailed analysis of the NOESY spectrum, supported by molecular dynamics calculations, suggested that some unexpected NOEs were due to the sum of many small dipolar effects, whose identification was possible only by considering the 3D structure of an Ochain oligosaccharide bigger than the repeating unit.


369) Soil burial and enzymatic degradation in solution of aliphatic co-polyesters

P.Rizzarelli, C.Puglisi, G.Montaudo

Polymer Degradation and Stability  85(2),  855  - 2004

A series of high molar mass aliph. homo- and co-polyesters was obtained from 1,4-butandiol and Me esters of succinic, adipic, sebacic acids, and these materials were characterised by 1H NMR, SEC, DSC, X-ray and viscosity. Good filmability was achieved for all the polymers. The biodegradability of poly(butylene succinate-co-butylene sebacate), P(BSu-co-BSe), and poly(butylene succinate-co-butylene adipate), P(BSu-co-BAd), samples, with different compn., was investigated under controlled soil burial conditions. Film samples were also assayed to enzymic attack by lipase from Mucor miehei or from Rhizopus arrhizus. The biodegrdn. was evaluated as wt. loss and the relative normalized wt. loss rates were compared. The influence of crystallinity, molar mass, chem. structure and melting temp. upon biodegrdn. was studied. The wt. loss of poly(3-hydroxy butyrate), P(HB), of poly(3-hydroxy butyrate-co-3-hydroxy valerate) 76/24, P(HB-co-HV) 76/24, and of two com. Bionolle samples, was also investigated under soil burial conditions. The results allow a direct comparison of the soil burial degradability of polyesters having different structures.


370) MALDI Investigation of the Photooxidation of Nylon-66

S.Carroccio, C.Puglisi, G.Montaudo

Macromolecules  37(16),  6037  - 2004

Matrix-assisted laser desorption ionization mass spectrometry (MALDI) was used to det. the structure of the mols. produced in the photooxidative degrdn. of nylon-66 at 60 °C in air. The MALDI spectra of the photooxidized nylon-66 (Ny66) show the presence of nearly 40 compds., as compared to only four in the original Ny66 sample, and provide information on the structure and end groups of the oligomers produced in the oxidn. The structural anal. of the photooxidized species provided by the MALDI spectra allowed drawing a detailed map of the photodecompn. mechanisms of Ny66. Our results extend the currently accepted picture for the photooxidn. mechanisms of Ny66, confirming previous insights into the hydrogen abstraction and subsequent formation of a hydroperoxide intermediate, but also reveal that Norrish I and Norrish II chain cleavage reactions play an important role in the photooxidn. process of Ny66. Ny66 films exposed for 12 h show the appearance of only photooxidn. products generated by the hydrogen peroxide decompn., indicating that the chain photocleavage reactions Norrish I and Norrish II type do occur at a later stage of irradn. An explanation is offered for the appearance of this induction period. It is expected that future MALDI studies may have an impact on the current views on photooxidn. processes of other polymer systems.


371) Molecular architecture of poly[(R,S)-3-hydroxybutyrate-co-6-hydroxyhexanoate] and poly[(R,S)-3-hydroxybutyrate-co-(R,S)-2-hydroxyhexanoate] oligomers investigated by electrospray ionization ion-trap multistage mass spectrometry

G.Adamus, M.S.Montaudo, G.Montaudo, M.Kowalczuk

Rapid Communications in Mass Spectrometry  18(13),  1436  - 2004

A series of aliph. copolyesters was obtained from (R,S)-β-butyrolactone and two isomeric hydroxy acids, 6-hydroxyhexanoic and (R,S)-2-hydroxyhexanoic acids. The reactions were conducted in bulk without catalyst. Electrospray ionization tandem mass spectrometry (ESI-MSn) was used for mol. characterization of these copolyester oligomers. The mass spectra of the copolyesters studied have enabled identification of their mol. structures including chem. nature of the end groups (hydroxyl and carboxylate). The compns. of the oligocopolyesters and their sequence distributions were detd. based on measurement of the relative intensities of the individual oligocopolyester peaks in the ESI mass spectra. The mass spectra (MS1) provided information on compn. and sequence distribution, and small deviations from Bernoulli statistics were detected. The arrangement of co-monomer structural units along the oligopolyester chains was verified by MS/MS expts. and investigation of the fragmentation pathways.


372) MALDI Investigation of Photooxidation in Aliphatic Polyesters: Poly(butylene succinate)

S.Carroccio, P.Rizzarelli, C.Puglisi, G.Montaudo

Macromolecules  37(17),  6576  - 2004

DOI: https://pubs.acs.org/doi/10.1021/ma049633e
Matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF-MS) has been found to be an excellent method to det. the structure of the mols. produced in the photooxidative degrdn. of poly(butylene succinate) (PBSu) at 60 °C in air. Over 20 compds. are present in the MALDI spectrum of the oxidized sample, as compared to only 4 in the original PBSu sample. The MALDI spectra present many new well-resolved peaks, which provide information on the structure and end groups of the oxidn. products. The MALDI peaks correspond to sodiated ions of oxidized oligomers, and they have been assigned to polymer chains contg. succinic and malonic acid, Bu ester, Et ester, and Bu formate end groups. These oligomers had not been revealed before. The mechanisms accounting for the formation of photooxidn. products of PBSu involve the operation of several reactions: (i) oxidn. of hydroxyl end groups; (ii) a-H abstraction decompn.; (iii) Norrish I photocleavage. Our results establish the photooxidn. mechanisms of PBSu. The novelty of our approach consists of using a nonaveraging technique, such as mass spectrometry, which allows the detection of individual compds. formed during the oxidn. process. This is a remarkable result, and it should be expected that future MALDI studies might have an impact on the current views on photooxidn. processes of other polymer systems.


373) Structural Characterization of Copolyamides Synthesized via the Facile Blending of Polyamides

F.Samperi, M.S.Montaudo, C.Puglisi, S.Di Giorgi, G.Montaudo

Macromolecules  37(17),  6449  - 2004

Ny6-Ny6,10 and Ny6-Ny4,6 copolyamides prepd. by a facile melt mixing at 290-310 °C of carboxyl terminated Nylon6 (Ny6-COOH) with Ny6,10 or Ny4,6, were characterized by MALDI, 13C NMR, and DSC anal. The results, from one side show how facile is the high yield synthesis of random copolyamides via the melt mixing of the corresponding polyamides. What makes the synthesis so facile is the use of a carboxyl terminated polyamide (Ny6-COOH) to attack the other polyamide (Ny4,6 or Ny6,10), as described herewith. The DSC data acquired provide a clear picture of the process. The second relevant point is about the sequence anal. of the copolyamides, made using their 13C NMR spectra. The sequence has been derived directly from chain statistics principles, avoiding the use of inadequate procedures. To our knowledge, this is the first time as far as condensation copolymers are concerned. Interesting, the sequence anal. of our copolyamides has been also performed independently, by extg. pertinent information from their MALDI spectra. The results have been found in excellent agreement with those from 13C NMR data.


374) Is It Possible to Extend the Coleman-Fox Method for Polymer Sequence Determination by NMR to Copolycondensates?

M.S.Montaudo

Journal of Physical Chemistry B  108(20),  6288  - 2004

A theory is presented for the interpretation of NMR spectra of copolycondensates, with special attention to those obtained by melt mixing of two macromol. chains (reactive blending). The repeat unit is split into two parts, referred to as half-monomers. The present theory gives a highly accurate description of the changes in the sequence distribution during the reactive blending reaction, since the effect of the first and second neighbors along the macromol. backbone (half-monomer penultimate effect) is explicitly considered. The theor. predictions are compared with exptl. data taken from the literature and, more specifically, NMR data concerning five copolymer systems, namely, a copolymer obtained by reactive blending of poly(ethylene terephthalate) and poly(ethylene adipate), an almost alternating copolymer with units of ether-sulfone and ether-ketone, a copolymer derived from 6-methyl-2,5-morpholinedione, and two copolymers obtained by reactive blending of poly(butylene terephthalate) with poly(bisphenol-A carbonate) and Nylon 6.


375) MALDI for the estimation of viscosity parameters. A modified method which applies also to polycondensates

M.S.Montaudo

Polymer  45(18),  6291  - 2004

Recently, a method based on MALDI was described for the estn. of the parameters which characterize the viscosity of a polymer, namely the Mark-Houwink-Sakurada (MHS) parameters. The method makes use of samples with a narrow molar mass distribution and therefore, for polycondensates, it may become unpractical. A modification is proposed here, based on the universal calibration concept and on the coupling of size exclusion chromatog. and MALDI. The new method is applied to two copolymers with units of styrene and maleic-anhydride and to a series of polymers and copolymers obtained by condensation. The MHS parameters are measured and they are compared with the values predicted by the method of adding the contributions coming from each functional group present in the chain, which is able to predict MHS parameters from first principles.


376) Molecularly engineered silica surfaces with an assembled porphyrin monolayer as optical NO2 molecular recognizers

A.Gulino, P.Mineo, E.Scamporrino, D.Vitalini, I.Fragala

Chemistry of Materials  16(10),  1838  - 2004

The assembly of the porphyrin 5,10,15-tri-(p-dodecanoxyphenyl)-20-(p-hydroxyphenyl) porphyrin (P) with SiO2 surfaces was studied with regard to its use as NO2 sensor based on optical recognition. The assembly called P-AM was synthesized by 3 successive steps. Fused SiO2 substrates were first cleaned and dried. The substrates were then immediately emersed in a n-heptane soln. of the chemisorptive siloxane, trichloro[4-(chloromethyl)phenyl] silane, to afford a monolayer of the coupling agent (CA). The silylated substrates were finally immersed in a DMF soln. of the P Na salt. N 1s angle-resolved X-ray photoelectron spectra of the P-AM showed features accounting for the 2 kinds of N in the free porphyrin base. The UV/Vis spectrum of the P-AM showed high quality signals and found counterparts in that of P in THF. Both showed a characteristic sharp Soret band at 425 nm. The NO2 sensing capability tested in soln. showed an evident intensity decrease of the Soret band parallel to the increase of 2 addnl. bands at 452 and 685 nm after 10 s of NO2 bubbling. Upon NO2 gas exposure the UV/vis spectra of the P-AM showed the disappearance of the Soret band whereas a new band at 462 appeared.


377) The complete structure of the lipooligosaccharide from the halophilic bacterium Pseudoalteromonas issachenkonii KMM 3549T

A.Silipo, S.Leone, R.Lanzetta, M.Parrilli, L.Sturiale, D.Garozzo, E.L.Nazarenko, R.P.Gorshkova, E.P.Ivanova, N.M.Gorshkovac, A.Molinaro

Carbohydrate Research  339,  1985  - 2004

Novel lipooligosaccharide components were isolated and identified from the lipooligosaccharide fraction of the halophilic marine bacterium Pseudoalteromonas issachenkonii type strain KMM 3549T. The complete structure was achieved by chemical analysis, 2D NMR spectroscopy and MALDI mass spectrometry as the following: β-Gal-(1->7)-α-Hep3P-(1->5)-α-Kdo4P-(2->6)-LipidAα-Glc-(1->4)-β-Gal-(1->4) All sugars are D-pyranoses. Hep is L-glycero-D-manno-heptose, Kdo is 3-deoxy-D-manno-oct-2-ulosonic acid, P is phosphate, residues and substituents in italic are not stoichiometrically linked. In addition, by MALDI mass spectrometry of the intact LOS, the lipid A moiety was also identified as a mixture of penta-, tetra- and triacylated species.


378) A novel type of highly negatively charged lipooligosaccharide from Pseudomonas stutzeriOX1 possessing two 4,6- O-(1-carboxy)-ethylidene residues in the outer core region 4,6- O-(1-carboxy)-ethylidene residues in the outer core region

S.Leone, V.Izzo, A.Silipo, L.Sturiale, D.Garozzo, R.Lanzetta, M.Parrilli, A.Molinaro, A.Di Donato

European Journal of Biochemistry  271(13),  2691  - 2004

Pseudomonas stutzeri OXI is a Gram-negative microorganism able to grow in media containing aromatic hydrocarbons. A novel lipo-oligosaccharide from P. stutzeri OX1 was isolated and characterized. For the first time, the presence of two moieties of 4,6-O-(1-carboxy)-ethylidene residues (pyruvic acid) was identified in a core region; these two residues were found to possess different absolute configuration. The structure of the oligosaccharide backbone was determined using either alkaline or acid hydrolysis. Alkaline treatment, aimed at recovering the complete carbohydrate backbone, was carried out by mild hydrazinolysis (de-Oacylation) followed by de-N-acylation using hot KOH. The lipo-oligosaccharide was also analyzed after acid treatment, attained by mild hydrolysis with acetic acid, to obtain information on the nature of the phosphate and acyl groups. The two resulting oligosaccharides were isolated by gel permeation chromatography, and investigated by compositional and methylation analyses, by MALDI mass spectrometry, and by 1H-, 31P- and 13C-NMR spectroscopy. These experiments led to the identification of the major oligosaccharide structure representative of core region-lipid A. All sugars are D-pyranoses and a-linked, if not stated otherwise. Based on the structure found, the hypothesis can be advanced that pyruvate residues are used to block elongation of the oligosaccharide chain. This would lead to a less hydrophilic cellular surface, indicating an adaptive response of P. sutzeriOX1 to a hydrocarbon-containing environment. A novel lipo-oligosaccharide from P. stutzeri OX1 was isolated and characterized. For the first time, the presence of two moieties of 4,6-O-(1-carboxy)-ethylidene residues (pyruvic acid) was identified in a core region; these two residues were found to possess different absolute configuration. The structure of the oligosaccharide backbone was determined using either alkaline or acid hydrolysis. Alkaline treatment, aimed at recovering the complete carbohydrate backbone, was carried out by mild hydrazinolysis (de-Oacylation) followed by de-N-acylation using hot KOH. The lipo-oligosaccharide was also analyzed after acid treatment, attained by mild hydrolysis with acetic acid, to obtain information on the nature of the phosphate and acyl groups. The two resulting oligosaccharides were isolated by gel permeation chromatography, and investigated by compositional and methylation analyses, by MALDI mass spectrometry, and by 1H-, 31P- and 13C-NMR spectroscopy. These experiments led to the identification of the major oligosaccharide structure representative of core region-lipid A. All sugars are D-pyranoses and a-linked, if not stated otherwise. Based on the structure found, the hypothesis can be advanced that pyruvate residues are used to block elongation of the oligosaccharide chain. This would lead to a less hydrophilic cellular surface, indicating an adaptive response of P. sutzeriOX1to a hydrocarbon-containing environment.


379) Characterisation of the α-(1-->3) Homopolymer of L-glycero-D-manno-Heptose Units Isolated from the O-Chain Polysaccharide of Agrobacterium radiobacter

C.De Castro, L.Sturiale, M.Parrilli

European Journal of Organic Chemistry  2004(11),  2436  - 2004

This paper provides the first report of the molecular primary structure of the O-chain produced from A. radiobacter group M2-1. The repeating unit was determined, by means of chemical and spectroscopical analyses, to have the following structure: [3)-α-L-glycero-D-manno-heptose-(1-->]n. The relevant feature of this structure is represented by the particular residue involved: L-glycero-D-manno-heptose. This monosaccharide is almost ubiquitous in Gram-negative bacteria, but it is exclusively located in the Core region and only in one other case has it is reported as an O-chain constituent. The knowledge of the chemical structure of the O-chain of A. radiobacter will be useful for comprehending the bacterium-host recognition mechanism at the molecular level.


380) Structure Elucidation of the Highly Heterogeneous Lipid A from the Lipopolysaccharide of the Gram-Negative Extremophile Bacterium Halomonas Magadiensis Strain 21 M1 Lipopolysaccharide of the Gram-Negative Extremophile Bacterium Halomonas Magadiensis Strain 21 M1

A.Silipo, L.Sturiale, D.Garozzo, C.De Castro, R.Lanzetta, M.Parrilli, W.D.Grant, A.Molinaro

European Journal of Organic Chemistry   10,  2263  - 2004

Halomonas magadiensis (formerly named Halomonas magadii) is a Gram-negative extremophilic and alkaliphilic bacterium isolated from Lake Magadi, which is located in the East African Rift Valley. Several members of the halomonad group of bacteria have been shown to inhabit the alkaline brines, including a new member, Halomonas magadiensis strain 21 M1 (NCIMB 13595), an organism that grows at high pH and relatively high salt concentration. The unusual structure of the lipid A family derived from the lipopolysaccharide of Halomonas magadiensis is reported herein. The structure was determined using chemical analysis, NMR spectroscopy and MALDI-TOF mass spectrometry. Lipid A was also analysed after either de-O-acylation or dephosphorylation. The resultant mixture was very heterogeneous in fatty acid substitution, from heptaacyl to triacyl species. The various lipid A molecules obtained by the removal of one or more acyl substituents from the heptaacyl species are described below.


381) Exopolysaccharides produced by a clinical strain of Burkholderia cepacia isolated from a cystic fibrosis patient

P.Cescutti, G.Impallomeni, D.Garozzo, L.Sturiale, Y.Herasimenka, C.Lagatolla, R.Rizzo

Carbohydrate Research  338(23),  2687  - 2003

Burkholderia cepacia is an opportunistic pathogen involved in pulmonary infections related to cystic fibrosis. A clinical strain, BTS13, was isolated and the production of exopolysaccharides was tested growing the bacteria on two different media, one of which was rich in mannitol as carbon source. The primary structure of the polysaccharides was determined using mostly mass spectrometry and NMR spectroscopy. On both media an exopolysaccharide having the following repeating unit was produced: → 5) -β-KDop-(2→3)-β-D-Galp2Ac-(1→4)-α-D-Galp-(1→3)-β-D-Galp-(1→. This polysaccharide has already been described as the biosynthetic product of another Burkholderia species, B. pseudomallei, the microbial agent causing melioidosis. In addition to this, when grown on the mannitol-rich medium, B. cepacia strain BTS13 produced another polysaccharide that was established to be levan: →6)-β-D-Fruf-(2→. The content of levan was about 20% (w/w) of the total amount of polymers. The ability of B. cepacia to produce these two exopolysaccharides opens new perspectives in the investigation of the role of polysaccharides in lung infections.


382) A calorimetric study of binary mixtures containing some glycols and polyglycols+anisole at 308.15 K and at atmospheric pressure

F.Comelli, S.Ottani, D.Vitalini, R.Francesconi

Thermochimica Acta  407(1-2),  85  - 2003

Excess molar enthalpies, HmE, of binary mixts. of anisole+glycols and polyglycols were measured by a flow microcalorimeter at 308.15 K and at atm. pressure over the whole compn. range. Binary mixts. contained anisole+diethylene glycol, anisole+triethylene glycol, anisole+tetraethylene glycol, anisole+poly(ethylene glycol)-200, anisole+poly(ethylene glycol)-300, anisole+poly(ethylene glycol)-400, anisole+poly(ethylene glycol)-600. Effects of the mol. wt. distribution (MWD), of the polymer were investigated too, by prepg. three addnl. samples of poly(ethylene glycol) (PEG) with the same no. av. mol. wt. (Mn»300), but different MWD. Values of HmE of the corresponding binary mixts. with anisole were measured. For all mixts., results were fitted to the Redlich-Kister polynomial. HmE curves are asym., showing pos. deviations for mixts. contg. glycols and poly(ethylene glycol)-200, neg. deviations for poly(ethylene glycol)-600, and an inversion of sign in the other cases. Values of HmE vary from a max. of 440 J mol-1 (anisole+triethylene glycol) to a min. of -390 J mol-1 (anisole+poly(ethylene glycol)-600). Effects of changes in the glycols chain length and in MWD on the mol. interactions between the mixt. components are discussed.


383) Essential role of chain ends in the nylon-6/poly(ethylene terephthalate) exchange

F.Samperi, C.Puglisi, R.Alicata, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  41(18),  2778  - 2003

A combination of NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) techniques were suitable tools for examg. the exchange reactions that occur during the melt-mixing of nylon-6 and poly(ethylene terephthalate) (Ny6/PET) blends in the presence of p-toluene sulfonic acid (TsOH) at 285 °C. Some researchers believe that TsOH is an efficient catalyst for the amide-ester exchange reactions in PET/Ny6 and PET/nylon-66 blends in the molten state. Instead, we have found that TsOH is able to react in the molten state with PET, yielding PET oligomers terminated with carboxyl groups. Because the latter oligomers can quickly react with Ny6 producing a Ny6/PET copolymer, the role of TsOH in the melt-mixing process is not that of a catalyst but of a reactant. Our study allowed the structural identification of the Ny6/PET copolyesteramide produced in the exchange as a function of melt-mixing time. The results revealed the essential role of carboxyl end groups in the exchange reaction between Ny6 and PET and allowed a detailed mechanism for this reaction.


384) Inclusion Networks of a Calix[5]arene-Based Exoditopic Receptor and Long-Chain Alkyldiammonium Ions

D.Garozzo, G.Gattuso, F.H.Kohnke, A.Notti, S.Pappalardo, M.F.Parisi, I.Pisagatti, A.J.P.White, D.J.Williams

Organic Letters  5(22),  4025  - 2003

Tail-to-tail connection of two cone calix[5]arene moieties by a rigid p-xylyl spacer affords the new exoditopic receptor 3 featuring two ð-rich cavities (assembling cores) in a centrosymmetric divergent rrangement, as established by a single-crystal X-ray analysis. 1H NMR complexation studies of 3 with alkyldiammonium ions support the formation of discrete bis-endo-cavity complexes and/or capsular assemblies along a polymer chain (polycaps), according to the length of the connector.


385) Essential Role of Chain Ends in the Ny6/PBT Exchange. A Combined NMR and MALDI Approach

F.Samperi, M.S.Montaudo, C.Puglisi, R.Alicata, G.Montaudo

Macromolecules  36(19),  7143  - 2003

A combination of NMR and MALDI was found to be a suitable tool to study the exchange reactions that occur during the melt mixing of Nylon-6 and poly(butylene terephthalate) (Ny6/PBT) blends. The results reveal the essential role of carboxyl end groups in the exchange reaction, and allow drawing a detailed mechanism for this reaction. Using Ny6 and PBT samples bearing specific reactive end groups, it was demonstrated that only the carboxyl end groups of PBT and of Ny6 are able to react in the initially biphasic Ny6/PBT blends, so that an outer-inner exchange takes place (Scheme 3). The compn. of the copoly(esteramide) obtained at 260 °C in the exchange of Ny6/PBT shows a higher amt. of Ny6 units with respect to the initial blend compn. and a high value of the Ny6 av. sequence length. However, the compn. of the copoly(esteramide) obtained at 280 °C was instead found to be equal to the feed compn. (50/50), with a random distribution of av. sequence lengths. The results obtained in the present work can be reconciled within the overall model of exchange reaction occurring through active chain ends


386) New Vistas in the Photo-Oxidation of Nylon 6

S.Carroccio, C.Puglisi, G.Montaudo

Macromolecules  36(20),  7499  - 2003

Matrix-assisted laser desorption ionization mass spectrometry (MALDI) is an excellent method to use in detg. the structure of the mols. produced in the photo-oxidative degrdn. of nylon 6 at 60 °C in air. The MALDI spectra of photo-oxidized nylon 6 (Ny6) show the presence of over 40 compds., as compared to only 3 in the blank Ny6 sample. The extremely favorable event here is that the MALDI spectra present so many new well-resolved peaks, which provide information on the structure and end groups of the oxidn. products. The structural anal. of the photo-oxidn. products provided by the MALDI spectra allowed us to draw a detailed map of the photo-oxidn. mechanisms of Ny6 (Schemes 1-4). The presence of the majority of the oligomers listed in Table 1 had not been revealed before. Our results extend and modify the currently accepted picture for the photo-oxidn. mechanisms of Ny6. In fact, our results confirm previous insights that the hydrogen abstraction and subsequent formation of a hydroperoxide intermediate actually occur but also reveal that Norrish I and Norrish II chain-cleavage reactions play an important role in the photo-oxidn. process of Ny6. This essential feature of the process had been missed in previous studies focused on UV and IR techniques. The peculiarity of our approach consists of using a high-sensitivity and nonaveraging technique such as mass spectrometry, which allows the detection and monitoring of each new oligomers formed during the oxidn. process. This is a remarkable result, and it should be expected that future MALDI studies may have an impact on the current views of photo-oxidn. processes of other polymer systems


387) Epoxy-silica polymers as restoration materials. Part II

P.Cardiano, P.Mineo, S.Sergia, R.C.Ponterio, M.Triscari, P.Piraino

Polymer  44(16),  4435  - 2003

Room temperature reaction of the epoxy resin poly(bisphenolA-co-epichlorohydrin), glycidyl end-capped with the coupling agent (3- aminopropyl)triethoxysilane, in 1:2 (1), 1:1 (2) and 2:1 (3) molar ratios, leads, after curing for three months at room temperature, to glassy, transparent, crack-free solids which were investigated by SEM, TGA, DSC, NIR and Raman spectroscopy. SEM investigations show substantially a great homogeneity over the entire area with absence of cracks, veins and/or fissures and without formations of clusters and/or aggregates. The conversion of oxirane rings, as found by Raman spectroscopy, decreases by increasing the epoxy/amine ratio, with conversion percentages ranging from 95.3 to 81.3%. As a common feature, the presence in 1, 2 and 3 of Si-O-Si linkages increases the polymer degradation temperature and thermal oxidative stability relative to the parent epoxy resin by shifting the weight loss to higher temperatures. Differently from mixtures 2 and 3, which show the Tg at 90 8C, the mixture 1 does not exhibit any detectable glass transition.


388) Insertion of copper(II)/Schiff-Base complexes with NLO properties into commercial polycarbonates by thermal processes

E.Scamporrino, S.Bazzano, D.Vitalini, P.Mineo

Macromolecular Rapid Communications  24(3),  236  - 2003

The preparation of a bisphenol-A carbonate copolymer, containing Cu-diime units with nonlinear optical (NLO) properties, and its MALDI-TOF mass spectrometric characterization are reported. Contrary to the usual synthetic method, NLO groups were inserted directly into a commercial polycarbonate by prolonged heating at 250degreesC. This innovative procedure allows to obtain a Cu/diimine-containing polymer of high molecular weight.


389) Spectroscopic evidence of aggregation processes in porphyrin-based star-polymers in aqueous solutions

V.Crupi, R.Giordano, D.Majolino, P.Migliardo, V.Venuti, N.Micali, V.Villari, P.Mineo, D.Vitalini, E.Scamporrino

Molecular Physics  101(10),  1517  - 2003

We present a spectroscopic analysis of the structural and dynamic properties of water solutions of uncharged star-polymers at different molecular masses, characterized by a porphyrin core and four poly(ethylene glycol) methoxy arms. The investigation has been performed by small angle neutron scattering (SANS) and Fourier transform infrared (FTIR) absorption technique. The aim of the present work is to investigate the aggregation processes in the above-mentioned systems by altering their natural pH and ionic strength upon the addition of an acid (hydrochloric acid, HCl) or a salt (potassium chloride, KCl). SANS data permitted us to check the size of the star-polymer in solution as a function of the ?perturbation substance? concentration. On the other hand, as far as the dynamical properties are concerned, the FTIR analysis performed at low frequency in the region from 200 to 700 cm -1, claimed a greater tendency to self-aggregate by porphyrin, having the lowest molecular mass.


390) Exchange Reactions Occurring through Active Chain Ends. MALDI-TOF Characterization of Copolymers from Nylon 6,6 and Nylon 6,10

C.Puglisi, F.Samperi, S.Di Giorgi, G.Montaudo

Macromolecules  36 (4),  1098  - 2003

A study on the sequence and composition of copolyamides formed by activated exchange reactions occurring in the melt mixing of Ny6,10 and Ny6,6 is reported. Equimolar mixtures of Ny6,10, Ny6,6, and carboxyl-terminated Ny6,6 (Ny6,6-COOH) samples were melt mixed at different temperatures (290-310 C) for different times (10-180 min). The determination of copolyamides formation, sequence, and composition proved to be unfeasible with 13C NMR spectroscopy. On the other hand, matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectra allowed the detection of the copolyamides formation and the determination of their sequence and composition. The results can be reconciled within the overall scheme of exchange reaction occurring through active chain ends. In fact, the composition of the copolyamides formed by the exchange of Ny6,6-COOH/Ny6,10 mixtures showed a higher amount of Ny6,6 units, with respect to the initial blends composition, and a higher value of the Ny6,6 average block length, at the beginning of the reaction (10 min). The composition of the copolyamides was found to be equal to the feed composition (50/50), after 30 min of heating, with a random distribution of sequences. The composition and the sequence distributions of the copolyamides remained unaffected even at a higher heating time (180 min) although some degradation reactions also occurred. Instead, the exchange reaction of a mixture of high molar mass Ny6,6 and Ny6,10 both containing a very low amount of carboxylic chain ends produced a segmented copolyamides even at high heating time (150 min). The Ny6,6/Ny6,10 copolyamides were also characterized by differential scanning calorimetry (DSC) and by wide-angle X-ray spectroscopy (WAXS)


391) Photo-oxidation products of polyetherimide ULTEM determined by MALDI-TOF-MS. Kinetics and mechanisms

S.Carroccio, C.Puglisi, G.Montaudo

Polymer Degradation and Stability  80(3),  459  - 2003

Poly 2,2-bis4-(3,4-dicarboxyphenoxy) phenylpropane dianhydride-1,3-phenylendiamine copolymer (ULTEM) was subjected to photo aging in the attempt to find evidence on the structure of the species formed in the oxidative degradation. The oxidation was followed as a function of the exposure time by MALDI and SEC/MALDI techniques. The SEC curves showed extensive degradation, with the formation of low molar mass oligomers having different end groups. Valuable structural information on the photo-oxidized ULTEM species was extracted from the MALDI spectra of the photo-oxidized ULTEM. These showed the presence of polymer chains containing acetophenone, phenyl acetic acid, phenols, benzoic acid, phthalic anhydride and phthalic acid end groups. The mechanisms accounting for the formation of photo-oxidation products involve several simultaneous reactions: (1) photo-cleavage of methyl groups of the N-methyl phthalimide terminal units; (2) photoxidative degradation of the isopropylidene bridge of BPA units; (3) photo-oxidation of phthalimide units to phthalic anhydride end groups: (4) hydrolysis of phthalic anhydride end groups. The kinetic behaviour of all the species detected is in agreement with the predictions of the reaction mechanisms hypothesized


392) Homologous disaccharide properties at low temperatures

L.Abate, I.Blanco, C.Branca, S.Magazu, G.Maisano, P.Mineo, G.Romeo

Journal of Molecular Liquids  103-104,  177  - 2003

To get some insight into the mechanisms of cryopreservation that characterize disaccharides, and to clarify the reasons that make trehalose the most effective bio-protector, we have analyzed the thermal properties of aq. trehalose, maltose and sucrose solns. by giving evidence that the trehalose/water soln. shows the strongest interaction strength between water and trehalose mols


393) Aggregation Phenomena in Aqueous Solutions of Uncharged Star Polymers with a Porphyrin Core

N.Micali, V.Villari, P.Mineo, D.Vitalini, E.Scamporrino, V.Crupi, D.Majolino, P.Migliardo, V.Venuti

Journal of Physical Chemistry B  107(21),  5095  - 2003

Uncharged star polymers having a porphyrin core and four poly(ethylene glycol)methyl ether (PEGME) arms have been synthesized and investigated (through the study of the structural and dynamical properties) as a function of the mol. mass of the arms, in different thermodn. conditions. Mols. with short PEGME arms are insol. in water, whereas in the presence of long PEGME chains, the star polymers are water-sol.; for the intermediate length of the arms, the building up of large rigid monodisperse aggregates, driven by the diffusion limit aggregation mechanism, has been obsd. by means of static and dynamic light scattering. These aggregated systems, whose sizes are modulated by changing the pH and triggered by the chain flexibility, can be well described in terms of the DLVO interparticle potential in the frame of the colloidal theory


394) Aggregation effects in aqueous solutions of Star-polymers by spectroscopic investigations

V.Crupi, D.Majolino, P.Migliardo, V.Venuti, N. Micali, V.Villari, P.Mineo, D.Vitalini, E.Scamporrino

Journal of Molecular Structure  651-653,  675  - 2003

A detailed spectroscopic anal. performed on aq. solns. of uncharged Star-Polymers, having a porphyrin core and four poly(ethylene glycol) methoxy terminated arms, at different mol. wt. values, by Elastic and Quasi-Elastic Light scattering and Fourier Transform IR absorption (FT-IR) has been reported. The aim of the present work is essentially to characterize the structural and dynamical properties of the studied samples by applying different spectroscopic techniques which permit to investigate different features of an unique problem.In particular from the light scattering measurements we showed that the species having higher mol. wt. (3600 and 8500 Da), have a very low scattered intensity compatible with the presence of the mols. in the monomer form. At the lowest investigated mol. wt. (2100 Da) mols. aggregate to form large supramol. structures. This tendency to aggregate was confirmed by FT-IR measurements performed in the same water solns. at low frequency (200-700) cm-1. Also the high frequency region, in the OH stretching vibrational range, (2800-3800) cm-1, has been investigated vs. the mol. mass of the star-polymer. From the comparison of the IR spectra in the case of star-polymers aq. solns. with the absorbance spectrum of bulk water, we showed a destructuring effect for the collective' band centered at about 3200 cm-1, which is related to the OH stretching of tightly bonded water mols. (tetrahedral water)


395) Surface evolution of polycarbonate/polyethylene terephthalate blends induced by thermal treatments

A.Licciardello, A.Auditore, F.Samperi, C.Puglisi

Applied Surface Science  203,  556  - 2003

Bisphenol-A polycarbonate (PC) and polyethyleneterephthalate (PET) blends are known to undergo, upon thermal treatment (melt mixing), exchange reactions leading to the formation of copolymers having a final structure that is also affected by consecutive reactions involving CO2 and ethylene carbonate losses. In this work we followed the evolution of the surface composition of this system during the melt mixing at 270 degreesC, both with and without catalysts, by means of time-of-flight secondary ion mass spectroscopy (ToF-SIMS). The static SIMS spectra obtained at different treatment times show the appearance of peaks related to newly formed structures and also the modification of the relative intensities of peaks characteristic of both the initial constituents of the blend. From the variation of the relative intensities of peaks related to the bisphenol-A unit of PC and to the phthalate structure of PET, it is shown that after the first stages of melt mixing the surface is PC enriched and that with the progressive formation of a random copolymer the phthalate units increase their concentration at the surface of the system. Hence, as final result of the melt mixing process, the surface composition tends to reflect the relative amount of the repeating units in the bulk.


396) ToF-SIMS investigation of the thermally induced processes at the surface of polyester based polymer blends

A.Auditore, F.Samperi, C.Puglisi, A.Licciardello

Composites Science And Technology  63(8),  1213  - 2003

Surface evolution caused by thermal processing at 270 degreesC of blends of bisphenol-A polycarbonate (PC) with polyethyleneterephthalate (PET) or with polybuthyleneterephthalate (PBT) has been investigated by ToF-SIMS. Such systems are known, upon melt mixing, to undergo transesterification reactions leading to the formation of copolymers. In the case of PET-PC, the transesterification is accompanied by reactions involving the loss of small molecules from the resulting copolymer, whereas the copolymer resulting from the trans-esterification of PBT-PC is stable at the temperature under consideration. We report on Static SIMS measurements performed on blend samples melt mixed for different times, that show a complex evolution of surface composition, explained also in terms of surface-specific processes, such as segregation of lower surface free energy components. The results from the melt mixed system are compared with those obtained from parallel temperature-programmed ToF-SIMS experiment, performed on spin-cast thin films.


397) Bivariate distribution in copolymers: A new model

M.S.Montaudo, G.Adamus, M.Kowalczuk

Journal of Polymer Science part A: Polymer Chemistry  40(14),  2442  - 2002

A new model for the bivariate distribution of chain sizes and composition in copolymers is presented. The model combines the sum of a two-bivariate distribution, and it replaces the previous model that consists of a single entity. The compositional distribution histogram was obtained by summation of the sections of the bivariate distribution that belong to a narrow compositional range. The predictions of the model were compared with mass spectrometric data relative to a block copolymer sample containing structural units of pivalolactone and 3-hydroxybutyrate with some literature data, namely, mass spectrometric data concerning a random copolymer sample reacted at high conversion containing units of styrene and methyl methacrylate as well as a block copolymer sample containing units of -methyl styrene and methyl methacrylate. The new model gives better results than the previous model because it fits better with the experimental compositional distribution histogram of the copolymer samples.


398) Mass spectra of copolymers

M.S.Montaudo

Mass Spectrometry Reviews  21(2),  108  - 2002

Recent and older literature (covering the last 12-13 years) in the field of mass spectra of random and block copolymers is reviewed. A detailed description is given of the information on copolymer properties that can be recovered from the analysis of the low-mass region of the spectrum (the region below 500 Da) and the high-mass region. The features of mass spectra of copolymers obtained by different synthetic routes are discussed, such as free radical, condensation, ring-chain equilibration, microbial synthesis, ring-opening, simple anionic, cationic, Ziegler-Natta, and/or metallocene catalysis, along with some random and block copolymers that occur in Nature. The emphasis is on copolymer composition and average molar mass determination, and on the benefits of coupling mass spectrometry (MS) with separation techniques such as size-exclusion chromatography (SEC) and high performance liquid chromatography (HPLC).


399) Thermal and themoxidative degradation processes in poly(bisphenol a carbonate)

G.Montaudo, S.Carroccio, C.Puglisi

Journal of Analytical and Applied Pyrolysis  64(2),  229  - 2002

Progress in the study of thermal and thermoxidative decomposition processes of poly(bisphenol a carbonate) (PC) was obtained by Matrix assisted laser description ionization time of flight (MALDI-TOF) and FAB mass spectroscopic techniques. PC samples were subjected to thermal degradation (under inert atmosphere) heating at 300, 350, 400 and 450 °C. The MALDI mass spectra of the pyrolysis residues obtained at 300 °C showed only a progressive reduction of the abundance of cyclic oligomers and an increase of the molar mass of the PC sample most likely due to post-condensation polymerisation reactions. At 350 °C the occurrence of an extensive hydrolysis reaction producing phenol groups was observed. PC chains terminated with phenol groups together with chains bearing phenyl and isopropenyl end groups were observed at 400 °C. Condensed aromatic compounds such as xanthones were also detected in the MALDI spectra of PC samples heated at 400 °C, and they became the most intense species at 450 °C. The FAB-MS spectrum of the pyrolysis residue obtained at 400 °C subjected to a selective and exhaustive aminolysis reaction showed the presence of compounds containing several consecutive xanthone units. These units undergo cross-linking processes, leading to a graphite-like charred residue (insoluble), as the temperature increases. The thermoxidative degradation of PC carried out heating the samples in air at 300 °C for 30, 60, 90, 120, 150 and 180 min produced a reduction of the PC molar mass. The MALDI mass spectra of thermally oxidised PC samples at 300 °C for 90 and 180 min showed the presence of PC chains terminated with methyl-ketone, phenyl and phenol groups, most likely formed by the oxidative degradation of the isopropilidene bridge of bisphenol A units. The presence of dehydrogenated structures containing biphenyl linkage may account for the insoluble residue produced in these conditions


400) MALDI-TOF characterisation of thermally generated gel from Nylon 66

C.Puglisi, F.Samperi, S.Di Giorgi, G.Montaudo

Polymer Degradation and Stability  78(2),  369  - 2002

Progress in understanding the thermal decomposition processes occurring in Nylon 66 (Ny66) was obtained by using matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry techniques. Ny66 samples were subjected to thermal degradation under inert atmosphere heating them at 290 and 315° C. The formation of a gel fraction was observed after about 15 min of heating and the addition of a condensing agent such as triphenyl phosphite (TPP) made the gelation complete in a few minutes. The MALDI-TOF mass spectra of the soluble fraction showed that secondary amino groups and cyclopentanone chain ends were generated in the heating process. The gel fraction was partially hydrolysed to destroy the network structure and the soluble material was analysed by MALDI-TOF. The spectra revealed the presence of N,N-substituted amide as side chains generated by the condensation of carboxyl end groups with secondary amino groups and azomethine structures originating from the reaction of cyclopentanone moieties with the terminaI amino groups. These structures were most likely responsible for the gel formation on heating Ny66 samples. Comparison with similar experiments conducted on Ny6, showed that only secondary amino groups were formed in Ny6, leading to branched structures but not to crosslinking.


401) Guest-induced capsular assembly of calix[5]arenes

D.Garozzo, G.Gattuso, F.H.Kohnke, P.Malvagna, A.Notti, S.Occhipinti, S.Pappalardo, M.F.Parisi, I.Pisagatti

Tetrahedron Letters  43(43),  7663  - 2002

Novel dimeric capsules are generated from the non-covalent assembly of cone calix[5]arenes and alkyldiammonium ions[H3N-(CH2)n-NH3]² featuring an appropriate length of the spacer joining the two charged end groups. ¹H NMR spectroscopy and electrospray ionisation mass spectrometry provide evidence that in the capsule a single ditopic guest holds together a pair of calix[5]arene units, which are oriented rim-to-rim to form a closed cavity encapsulating the shape-complementary dication.


402) Inibition of B16-BL6 Melanoma Lung Colonies by Semisynthetic Sulfaminoheparosan from E.coli K5 Polysaccharide

A.Poggi, C.Rossi, N.Casella, C.Bruno, L.Sturiale, C.Dossi, A.Naggi

Seminars in Thrombosis and Hemostasis  28(4),  383  - 2002

Heparin (H), heparan sulfate (HS), and related glycosaminoglycans can inhibit cancer cell invasion, possibly due to their ability to interact with vascular growth factors, adhesion molecules, endoglycosidases, and signaling proteins, in addition to the well-known effects on the clotting system. We evaluated the antitumor activity of a series of semisynthetic sulfaminoheparosan sulfates (SAHSs) with different degree and distribution of sulfates, obtained by chemical modifications of the E. coli K5 polysaccharide, namely type A, B, and C compounds. B16-BL6 melanoma cells (105 cells/mouse) were injected intravenously (i.v.) in a lateral tail vein of C57BL6 mice at a dose of 0.5 mg/ mouse together with test compounds. Tumor lung nodules were significantly reduced as compared with controls only by H (95.5 ± 1.0% inhibition), SAHS-2 (84.2 ± 5.0% inhibition), and SAHS-4 (91.1 ± 4.2% inhibition), among compounds tested. SAHS-2 and SAHS-4 are type B compounds, with a sulfate/carboxylate ratio similar to that of H. A typical mammalian HS showed only 54.8% inhibition. Supersulfated low-molecular-weight heparin and heparan sulfate (ssLMWH and ssLMWHS) showed an activity similar to that of unfractionated compounds. H and SAHS-4 inhibited dose dependently B16-BL6 lung colonies, with IC-50 values of 0.05 and 0.1 mg/mouse, respectively. The relationship with ex vivo anticoagulant potency was evaluated by activated partial thromboplastin time (aPTT) on mouse plasma at different time intervals after i.v. injection (0.1 to 0.5 mg/mouse) of the compound. H showed a dose-dependent anticoagulant activity lasting up to 2 hours, whereas SAHS-4 showed a potent anticoagulant effect only at a dose of 0.5 mg/mouse. Accordingly, H but not SAHS-4 consistently inhibited B16-BL6 lung colonies when given 1 hour before tumor cells. SAHS-4 derivatives, with different size and/or affinity depleted of AT binding sites, showed an inhibitory effect on B16-BL6 melanoma similar to that of SAHS-4, suggesting that the greater antitumor effect of H was not due to AT-mediated inhibition of blood clotting. Interactions with other blood inhibitors, such as heparin cofactor II or tissue factor pathway inhibitory protein cannot be ruled out. The better effect of H may be due to persistence in the circulation and/or ability to inhibit tumor neoangiogenesis


403) Densities, Viscosities, and Refractive Indices of Poly(ethylene glycol) 200 and 400 + Cyclic Ethers at 303.15 K

S.Ottani, D.Vitalini, F.Comelli, C.Castellari

Journal of Chemical & Engineering Data  47(5),  1197  - 2002

Densities, ρ, kinematic viscosities, ν, and refractive indices, nD, were determined for poly(ethylene glycol) 200 and 400 + 1,3-dioxolane, + 1,4-dioxane, + oxolane (tetrahydrofuran, THF), and + oxane (tetrahydropyran, THP) binary mixtures over the entire range of composition at 303.15 K and at atmospheric pressure. The excess molar volumes, Vm alla E , deviations in viscosities, Δη , and deviations in molar refractions, ΔR, calculated from experimental measurements, are always negative. The results were correlated with the Redlich-Kister polynomial. The McAllister multibody interaction model was used to correlate the kinematic viscosities of liquid mixtures with mole fractions. The viscosity dependence on temperature was investigated between 297.15 and 309.15 K for some solutions in a restricted composition range.


404) Synthesis and Characterization of Uncharged Water-Soluble Star Polymers Containing a Porphyrine Core

P.Mineo, D.Vitalini, E.Scamporrino

Macromolecular Rapid Communications  23(12),  681  - 2002

Uncharged water-soluble porphyrins were prepared by reaction between tetrakis(p-hydroxyphenyl)porphyrin and chlorinated poly(ethylene glycol) methyl ethers of different molecular weights. Water-solubility was achieved by binding four poly(ethylene glycol) branches to a porphyrin core to give star polymers with molecular weights in the range 2000-21 000 Da. Structural characterization of these star polymers was performed by means of gel permeation chromatography, NMR spectroscopy, and MALDI-TOF analysis.


405) Electrospray mass spectrometric studies of L-carnosine (beta-alanyl-L-histidine) complexes with copper(H) or zinc ions in aqueous solution

P.Mineo, D.Vitalini, D.La Mendola, E.Rizzarelli, E.Scamporrino, G.Vecchio

Rapid Communications in Mass Spectrometry  16(7),  722  - 2002

Electrospray ionization mass spectrometry (ESI-MS) was used for the speciation of supramolecular assemblies formed between equimolar amounts of carnosine and copper or zinc ions in dilute aqueous solutions. In the case of pure carnosine and carnosine/copper systems, the effect of pH changes, in the range 2-9, on the complexes surviving in solution was also explored. ESI data, besides supporting previous reported results on the formation of dimeric carnosine/copper and carnosine/zinc complexes, allowed a more complete speciation of the examined systems, bringing to light the existence of bis-complex species and, in the zinc case, the formation of oligomeric species. The data obtained for the systems investigated show that ESI-MS is not only a reliable and fast technique for the analysis of the metal/ligand systems, but also an interesting tool to obtain stoichiometric information on metal complexes formed in very low concentration solutions.


406) Thermal oxidation of poly(bisphenol A carbonate) investigated by SEC/MALDI

G.Montaudo, S.Carroccio, C.Puglisi

Polymer Degradation and Stability  77(1),  137  - 2002

Thermal oxidation products of poly(bisphenol A carbonate) (PC) generated by heating at 300 and 350 °C, respectively, under atmospheric air, were detected by an hyphenated SEC/MALDI technique. The SEC curves of the thermal oxidised samples showed extensive degradation as a function of heating time, up to the formation of very low mass oligomers. Oxidised PC samples were subjected to SEC fractionation by collecting several fractions which were analysed "off-line" by MALDI-TOF. The MALDI spectra of the SEC fractions of the thermal oxidised PC samples showed the presence of polymer chains containing acetophenone, phenyl substituted acetone, phenols, benzyl-alcohol and biphenyl terminal groups. The mechanisms accounting for the formation of thermal oxidation products of PC involve the operation of several simultaneous reactions: (i) hydrolysis of carbonate groups of PC to form free Bisphenol A end groups; (ii) oxidation of the isopropenyl groups of PC; (iii) oxidative coupling of phenols end groups to form biphenyl groups. The presence of biphenyl units among the thermal oxidation products confirmed the occurrence of cross-linking processes, which is responsible for the formation of the insoluble gel fraction.


407) Mass-Selective Lipase-Catalyzed Poly(E-caprolactone) Transesterification Reactions

M.Bankova, A.Kumar, G.Impallomeni, A.Ballistreri, R.A.Gross

Macromolecules  35(18),  6858  - 2002

Lipase-catalyzed intrachain transesterification reactions were studied in dry toluene (70°) using an immobilized form of Candida antarctica lipase B (Novozyme-435), poly(E-caprolactone), PCL, and hexanol/water as competitive nucleophiles. In addition to NMR and GPC, MALDI-TOF MS was also used to determine product molecular weight and end group structure. Experiments were conducted to determine (i) whether lipases cleave at random or specific sites along a polyester substrate and (ii) how reaction parameters such as the molecular weight of the starting polyester, reaction time, and nucleophile concentration effect the structure of the products formed. For the ratio of CL units to hexanol (22/1 mol:mol) and parent PCL Mn 56 400, calculations based on integration of¹H NMR spectra for the precipitated products showed that, after only 10 and 20 min reactions, about 60 and 70% of the PCL chains have terminal hexyl ester groups. Thus, transesterification reactions between PCL and hexanol occur rapidly. By 2 h, Novozyme-435 resolved the higher (A) and lower (B) molecular mass components of the starting polyester. This gave fraction A with Mnnd polydisperity (Mw/Mn)of 122 000 and 1.44, respectively. The "mass-selective" transesterification is evident in the GPC traces within 10 min, giving a product with Mnand polydispersity of 1810 and 1.6 (population D). Thus, the lipase cleaves short chain segments with an average length of 16 units by an endo-type mechanism. From 10 min to 24 h, it appears that condensation reactions of population D occur to give fraction C (Mn= 4040, Mw/Mn= 1.8, Mpeak = 7240). The results of this work show how enzymatic transesterification reactions can be further developed to provide oligomers with well-defined length and end group structure.


408) Identification of adulteration in water buffalo mozzarella and in ewe cheese by using whey proteins as biomarkers and matrix-assisted laser desorption/ionization mass spectrometry

R.Cozzolino, S.Passalacqua, S.Salemi, D.Garozzo

Journal of Mass Spectrometry  37(9),  985  - 2002

A rapid and accurate method to identify bovine and ewe milk adulteration of fresh water buffalo mozzarella cheese by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) is described. The differentiation among mozzarella made from water buffalo milk and from mixtures of less expensive bovine and, more recently, ewe milk with water buffalo milk is achieved using whey proteins, -lactalbumin and -lactoglobulins as molecular markers. It is worth noting that the method proposed here is, to our knowledge, the first strategy able to characterize possible fraudulent additions of ewe milk in samples of water buffalo milk devoted to the production of water buffalo mozzarella cheese. In addition, a linear relationship was found between the relative response of the molecular ion and the abundance of the analysed whey proteins. This demonstrates that this approach can be used to determine the amount of bovine or ovine milk added to water buffalo milk employed for mozzarella cheese production. Furthermore, this method also appears suitable for the analysis of ewe cheese. Hence these findings open the way to a new field for mass spectrometry in the evaluation of possible fraudulence in dairy industry production.


409) Biosynthetic Oligosaccharide Libraries for Identification of Protein-binding Heparan Sulfate Motifs. EXPLORING THE STRUCTURAL DIVERSITY BY SCREENING FOR FIBROBLAST GROWTH FACTOR (FGF) 1 AND FGF2 BINDING

P.Jemth, J.Kreuger, M. Kusche-Gullberg, L.Sturiale, G.GimÚnez-Gallego, U.Lindahl

Journal of Biological Chemistry  277(34),  30567  - 2002

Heparan sulfate is crucial for vital reactions in the body because of its ability to bind various proteins. The identification of protein-binding heparan sulfate sequences is essential to our understanding of heparan sulfate biology and raises the possibility to develop drugs against diseases such as cancer and inflammatory conditions. We present proof-of-principle that in vitro generated heparan sulfate oligosaccharide libraries can be used to explore interactions between heparan sulfate and proteins, and that the libraries expand the available heparan sulfate sequence space. Oligosaccharide libraries mimicking highly 6-O-sulfated domains of heparan sulfate were constructed by enzymatic O-sulfation of O-desulfated, end-group 3H-labeled heparin octasaccharides. Acceptor oligosaccharides that were 6-O-desulfated but only partially 2-O-desulfated yielded oligosaccharide arrays with increased ratio of iduronyl 2-O-sulfate/glucosaminyl 6-O-sulfate. The products were probed by affinity chromatography on immobilized growth factors, fibroblast growth factor-1 (FGF1) and FGF2, followed by sequence analysis of trapped oligosaccharides. An N-sulfated octasaccharide, devoid of 2-O-sulfate but with three 6-O-sulfate groups, was unexpectedly found to bind FGF1 as well as FGF2 at physiological ionic strength. However, a single 2-O-sulfate group in the absence of 6-O-sulfation gave higher affinity for FGF2. FGF1 binding was also augmented by 2-O-sulfation, preferentially in combination with an adjacent upstream 6-O-sulfate group. These results demonstrate the potential of the enzymatically generated oligosaccharide libraries.


410) New results on matrix-assisted laser desorption/ionization mass spectrometry of widely polydisperse hydrosoluble polymers

P.Malvagna, G.Impallomeni, R.Cozzolino, E.Spina, D.Garozzo

Rapid Communications in Mass Spectrometry  16(16),  1599  - 2002

Polyvinylpyrrolidone (PVP) of molecular weight (Mw) 40 000 and 160 000 and polydispersity of 1.8-2.2 was shown to yield matrix-assisted laser desorption/ionization (MALDI) mass spectra with the correct molar mass distribution of the polymer. This is a unique behavior among widely polydisperse samples and was ascribed to the capacity of PVP to complex the MALDI matrix. This result prompted us to test a new sample preparation technique consisting of flash-freezing followed by freeze-drying of the solution of the polymer with the matrix. In this paper we describe our preliminary results on MALDI-MS of polydisperse polymers obtained by this technique. This sample preparation method allowed us to obtain, for the first time, spectra yielding the true molecular weight distribution of polydisperse samples such as dextran, lichenan, nigeran, and poly(ethylene oxide).


411) Mechanisms of Thermal Oxidation of Poly(bisphenol A carbonate)

S.Carroccio, C.Puglisi, G.Montaudo

Macromolecules  35(11),  4297  - 2002

"In the attempt to find evidence on the structure of the species produced in the thermal oxidative degradation of bisphenol A-polycarbonate (PC), two polycarbonate samples, one capped (incompletely) with phenyl groups at both ends (PC1) and the other one capped (incompletely) with tert-butyl phenyl groups at both ends (PC2), were used. The two PC samples were heated at 300 and 350 C under atmospheric air for up to 180 min, producing a THF-insoluble gel at the longer heating times. The oxidative process was followed as a function of the exposure time by SEC, 1H NMR, MALDI-TOF, and SEC/MALDI-TOF techniques. The SEC curves showed extensive degradation, up to the formation of very low molar mass oligomers. Highly valuable structural information on the thermally oxidized PC species was obtained by using MALDI-TOF mass spectrometry. The MALDI-TOF spectra of the thermally oxidized PC1 and PC2 samples showed the presence of polymer chains containing acetophenone, phenyl-substituted acetone, phenols, benzyl alcohol, and biphenyl terminal groups. Formation of acetophenone and phenol end groups was confirmed by 1H NMR analysis. The mechanisms accounting for the formation of thermal oxidation products of PC involve the operation of several simultaneous reactions: (i) hydrolysis of carbonate groups of PC to form free bisphenol A end groups; (ii) oxidation of the isopropenyl groups of PC; (iii) oxidative coupling of phenols end groups to form biphenyl groups. The presence of biphenyl units among the thermal oxidation products confirmed the occurrence of cross-linking processes, which is responsible for the formation of the insoluble gel fraction. The MALDI-TOF analysis of the oxidation products of PC2 sample, capped with tert-butyl phenyl groups at both ends, unveiled a specific antioxidant action of these terminal groups, which are able to slow the rate of thermal oxidation of PC2 compared to PC1 sample."


412) End-Groups-Dependent MALDI Spectra of Polymer Mixtures

C.Puglisi, F.Samperi, R.Alicata, G.Montaudo

Macromolecules  35(8),  3000  - 2002

During a work designed to use MALDI-TOF MS to determine the composition of an equimolar blend of nylon 6 (Ny6) and polybutyleneterephthalate (PBT), the MALDI-TOF mass spectrum showed a surprising strong imbalance between the two components. The predominance of Ny6 oligomers over the PBT oligomers terminated with hydroxyl end chains is signaled by the appearance of specific peaks in the MALDI-TOF mass spectra. Since the average molar mass and the polydispersion of the two polymers are comparable, the MALDI-TOF MS ionization efficiency is quite different for the two components of the blend. This finding prompted us to a more detailed study, and to synthesize a number of Ny6 and PBT samples terminated with different end groups, to analyze their equimolar blends by MALDI-TOF MS. The results reported in the present study may help clarifying some fundamental aspects about the mechanisms of ions formation, when MALDI-TOF mass spectrometry is applied to macromolecules. End groups ionization efficiency appears to be the most important parameter in determining the relative intensity of peaks in the MALDI-TOF mass spectra of the polymer blends investigated. End-groups-dependent ionization of MALDI-TOF mass species is the key to rationalize the relative peak intensity in MALDI-TOF mass spectra of polymer mixtures. Understanding of ionization efficiency mechanisms is essential to the quantitative applications of MALDI-TOF MS.


413) Acid Catalyzed Transesterification as a Route to Poly(3-hydroxybutyrate- co-e-caprolactone) Copolymers from Their Homopolymers

G.Impallomeni, M.Giuffrida, T.Barbuzzi, G.Musumarra, A.Ballistreri

Biomacromolecules  3(4),  835  - 2002

Copolymers of (R)-3-hydroxybutyric acid (HB) and e-caprolactone (CL) with a composition ranging from 28 to 81 mol % of HB were synthesized by transesterification of the corresponding homopolymers in solution in the presence of 4-toluenesulfonic acid. The copolyesters were characterized with regard to their molecular weights, thermal properties, molar compositions, and average block length of repeating units by gel permeation chromatography (GPC), differential scanning calorimetry, 1H NMR, and 13C NMR, respectively. Random and microblock copolymers could be obtained depending on experimental conditions, with weight-average molecular weights of up to 20 000. The glass transition temperature decreased from 2 to -42 °C as the CL content was increased from 0 to 72 mol %. The melting temperature (Tm) of the PCL phase decreased from 70 to 46 °C as the HB content changed from 0 to 47 mol %, while the Tm of the PHB phase decreased from 177 °C to 163 °C as the CL content changed from 0 to 72 mol %. Matrix-assisted laser desorption ionization time-of-flight mass spectra of GPC fractionated samples allowed us to ascertain that copolymers rich in HB units have mostly hydroxyl and carboxyl end groups, while copolymers rich in CL units have mostly tosyl and carboxyl end groups.


414) Structural determination of lipid A of the lipopolysaccharide from Pseudomonas reactans

A.Silipo, R.Lanzetta, D.Garozzo, P.Lo Cantore, N.S.Iacobellis, A.Molinaro, M.Parrilli, A.Evidente

European Journal of Biochemistry  269(10),  2498  - 2002

The chemical structure of lipid A from the lipopolysaccharide of the mushroom-associated bacterium Pseudomonas reactans, a pathogen of cultivated mushroom, was elucidated by compositional analysis and spectroscopic methods (MALDI-TOF and two-dimensional NMR). The sugar backbone was composed of the beta-(1'-->6)-linked d-glucosamine disaccharide 1-phosphate. The lipid A fraction showed remarkable heterogeneity with respect to the fatty acid and phosphate composition. The major species are hexacylated and pentacylated lipid A, bearing the (R)-3-hydroxydodecanoic acid [C12:0 (3OH)] in amide linkage and a (R)-3-hydroxydecanoic [C10:0 (3OH)] in ester linkage while the secondary fatty acids are present as C12:0 and/or C12:0 (2-OH). A nonstoichiometric phosphate substitution at position C-4' of the distal 2-deoxy-2-amino-glucose was detected. Interestingly, the pentacyl lipid A is lacking a primary fatty acid, namely the C10:0 (3-OH) at position C-3'. The potential biological meaning of this peculiar lipid A is also discussed.


415) Thermal degradation of poly(ethylene oxide-propylene oxide-ethylene oxide) triblock copolymer: comparative study by SEC/NMR, SEC/MALDI-TOF-MS and SPME/GC-MS

G.Gallet, S.Carroccio, P.Rizzarelli, S.Karlsson

Polymer  43(4),  1081  - 2002

By comparing size exclusion chromatography/matrix assisted laser desorption ionisation (SEC/MALDI) and SEC/NMR spectra from virgin poly(ethylene oxide-propylene oxide-ethylene oxide) triblock copolymer, we were able to understand the bimodal distribution observed in poloxamer 407. Propylene oxide, isomerised to allyl alcohol during polymerisation, eventually forms a Poly(ethylene oxide-propylene oxide) diblock copolymer when EO is added to the feed. The oxidative thermal degradation of poloxamer 407 at 80°C in air was studied. We found by MALDI that degradation starts after 21 days in the PPO block of the copolymer. This result was confirmed by solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS): The first volatile degradation product to appear is 1,2-propanediol,1-acetate,2-formate. The structure of this molecule suggests that a six-ring intramolecular decomposition reaction of the PPO chain occurs at the very beginning of the polymer breakdown. Thus, the secondary hydroperoxide formed on the PPO chain plays a major role on the thermoxidation of poloxamer materials.


416) Minimal Heparin/Heparan Sulfate Sequences for Binding to Fibroblast Growth Factor-1

M.Guerrini, T.Agulles, A.Bisio, M.Hricovini, L.Lay, A.Naggi, L.Poletti, L.Sturiale, G.Torri, B.Casu

Biochemical and Biophysical Research Communications  292(1),  222  - 2002

"The glycosaminoglycans heparin and heparan sulfate (HS) bind to fibroblast growth factor FGF1 and promote its dimerization, a proposed prerequisite for binding to a cellular receptor and triggering mitogenic signals. The problem of minimal structural requirements for heparin/HS sequences to bind FGF1 was approached by surface plasmon resonance (SPR), NMR spectroscopy, and MALDI mass spectrometry studies using the three synthetic tetrasaccharides GlcNSO36OR-IdoA2SO3-GlcNSO36OR'-IdoA2SO3OPr (AA, R = R' = SO3; BA, R = H, R' = SO3; BB, R = R' = H; Pr, propyl). AA and BA significantly interact with the protein, whereas BB is practically inactive. The NMR spectra show that, whereas the interaction of AA primarily involves the GlcNSO36SO3IdoA2SO3 disaccharide moiety at its nonreducing end, residues at both the nonreducing (NR) and reducing side (R) appear to be involved in the weaker complex of BA. Furthermore, MALDI expts. show that, in addn. to 1:1 protein:tetrasaccharide complexes, AA and BA are able to form 2:1 complexes, indicating that heparin/HS-induced dimerization of FGF1 requires only one 6-OSO3 group per tetrasaccharide. (c) 2002 Academic Press."


417) Influence of chain end groups on the matrix-assisted laser desorption/ionization spectra of polymer blends

R.Alicata, G.Montaudo, C.Puglisi, F.Samperi

Rapid Communications in Mass Spectrometry  16(4),  248  - 2002

The positive ion matrix-assisted laser desorption/ionization (MALDI) spectrum of an equimolar blend of Nylon 6 (Ny6) and hydroxyl-terminated polybutyleneterephthalate (PBT) shows a surprisingly strong imbalance between the two components. Since the average molar masses and the polydispersions of the two polymers are comparable, it follows that the efficiency of MALDI is quite different for the two components of the blend. This finding prompted us to a more detailed study, and to synthesize Ny6 and PBT samples terminated with different end groups, in order to analyze their blends by MALDI. The negative ion MALDI spectra of the mixtures investigated show that PBT samples do not yield signals, so that only Ny6 peaks appear in these spectra. By comparing positive and negative ion MALDI spectra of mixtures of Ny6 terminated with various end groups, it was found that the peak intensity depends on the nature of the end groups. The results reported in the present study may help to clarify some fundamental aspects of the mechanisms of ion formation, when MALDI mass spectrometry is applied to macromolecules. End group ionization efficiency appears to be the most important parameter in determining the relative intensity of peaks in the MALDI spectra of the polymer blends investigated. End-group-dependent ionization is the key to the rationalization of the relative peak intensities in MALDI spectra of polymer mixtures. Copyright (C) 2002 John Wiley Sons, Ltd.


418) Full copolymer characterization by SEC-NMR combined with SEC-MALDI

M.S.Montaudo

Polymer  43(5),  1587  - 2002

Measurements on a series of random copolymers with units of methylmethacrylate, butylacrylate, styrene and maleic-anhydride are performed. A method is used which consists in fractionating the copolymer by size exclusion chromatography (SEC), collecting 30-40 fractions and then recording both the NMR and MALDI spectra of the fractions. In a successive step. bivariate distribution of chain sizes and composition maps are derived from knowledge of the molar mass, weight and composition of the copolymer fractions. The compositional distribution is obtained by summation of the sections of the bivariate distribution which belong to a narrow compositional range. A model for SEC fractionation of copolymers is developed. It allows to predict the composition and D(x) of the SEC fraction (D(x) is the ratio between the number-average and the weight-average molar mass, x is the fraction number). Offline SEC-MALDI measurements are performed, in order to measure experimentally D(x) for the random copolymer. The agreement between theoretical and experimental values for D(x) and for the composition of the SEC fraction (as derived from SEC-NMR measurements) is good. The predictions of the model were also compared with literature data for SEC fractionation of a copolyester with units of butileneadipate and butilenesebacate. The agreement between theoretical and experimental values is more than satisfactory. (C) 2002 Published by Elsevier Science Ltd


419) Oxygen transfer rate and sophorose lipid production by Candida bombicola

V.Guilmanov, A.Ballistreri, G.Impallomeni, R.A.Gross

Biotechnology and Bioengineering  77(5),  489  - 2002

Sophorose lipids (SLs) have applications as surfactants and are produced at high levels by several yeasts. We developed a fed-batch shake-flask method for the production of SLs by Candida bombicola ATCC 22214. Optimal aeration, expressed in terms of oxygen transfer rate, was between 50 and 80 mM O2/L h-1 and resulted in maximum values for both volumetric product formation (1-1.5 g/L h-1) and SL yield (350 g/L). The lowest aeration levels resulted in the enrichment in saturated fatty acid SLs at the expense of unsaturated fatty acid SLs.


420) Studies on the Interactions of the New 2, 6-Bis[2-(heteroaryl)vinyl]-1-methylpyridinium Cations with the Decamer d(CGTACGTACG)2

M.Fichera, C.G.Fortuna, G.Impallomeni, G.Musumarra

European Journal of Organic Chemistry  2002(1),  145  - 2002

The synthesis and spectroscopic characterization of 2,6-bis[2-(heteroaryl)vinyl]-1-methylpyridinium iodides (heteroaryl = 1-methylpyrrol-2-yl, furan-2-yl, thiazol-2-yl, imidazol-2-yl, 5-bromofuran-2-yl) is reported. Interactions of furan and pyrrole derivatives with the decamer duplex d(CGTACGTACG)(2) were clearly detectable by UV/Vis, CD, and H-1 NMR spectroscopy, and attention is drawn to the complementarity of the above techniques in such studies. The NMR evidence is consistent with literature data ascribed to intercalation


421) Testing a fluorinated compound as a protective material for calcarenite

P.Rizzarelli, C.La Rosa, A.Torrisi

Journal of Cultural Heritage  2(1),  55  - 2001

A polyfluorinated compound was studied as a material for the specific protection of calcarenite. Water capillary absorption and vapour permeability measurements were carried out in order to evaluate efficiency as a protective agent. Particular attention as given to characterising its resistance against bio-deterioration induced by microorganisms such as blue and green algae. Chemical surface modifications were induced by UV-irradiation in a specially designed climatic chamber and were investigated through comparative tests on untreated and artificially weathered samples using X-ray photoelectron spectroscopy (XPS). This paper discusses the potential use of the compound studied as a specific coating material for the protection of calcarenite.


422) Comparison of thermophysical properties in disaccharide aqueous solutions

C.Branca, S.Magazu, G.Maisano, P.Migliardo, P.Mineo

Physica Scripta  64(4),  390  - 2001

To get some insight into the mechanisms of cryopreservation that characterize disaccharides, and to clarify the reasons that make trehalose the most effective bio-protector, we report measurements on trehalose, maltose, and sucrose aq. solns. To analyze the interaction mechanisms of the three homologous disaccharides with water, we have investigated the volumetric properties of the three disaccharide solns., by performing d. and ultrasonic velocity measurements at different concn. and temp. values. In addn., we analyze the thermal properties of trehalose, maltose and sucrose aq. solns. by using Differential Scanning Calorimetry (DSC) and Thermogravimetry (TGA). What emerges from these studies is that trehalose shows, in comparison with maltose and sucrose, the smallest values of the partial molar volume in all the investigated temp. range, this circumstance being indicative of a more packed conformational arrangement esp. at the lowest temps. Furthermore, trehalose reveals, in respect to the other disaccharides, the greatest structural sensitivity to temp. changes. Finally, calorimetric measurements indicate a greater effectiveness of trehalose in destroying the tetrahedral network of water compatible with the formation of ice, supporting the hypothesis of a higher "fragile" thermodn. character of the trehalose-water system at high diln. Preliminary TGA and DTG findings reveal a noticeable stronger trehalose-water interaction mechanism and a significant higher thermal stability of the trehalose system.


423) MALDI mass spectrometry as a tool for characterizing glycosaminoglycan oligosaccharides and their interaction with proteins

L.Sturiale, A.Naggi, G.Torri

Seminars in Thrombosis and Hemostasis  27(5),  465  - 2001

Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry (MS) has emerged as a powerful, sensitive technique for structural anal. of glycosaminoglycans (GAGs) and their fractions and fragments. Whereas the mol. size of low sulfated or nonsulfated species (such as low-mol. wt. [LMW] K5 polysaccharides) can be directly detd. up to mol. wts. (MWs) of 12 kD, polysulfated species require complexing with a basic polypeptide and at present can be characterized (in terms of both MW and end residues) up to the size of a decasaccharide, even in complex mixts. MALDI spectra of GAG oligosaccharides in the presence of a complexing protein permit to assess binding to the protein and the presence of multimeric complexes.


424) Sequence analysis of heparan sulfate epitopes with graded affinities for fibroblast growth factors 1 and 2

J.Kreuger, M.Salmivirta, L.Sturiale, G.Gimenez-Gallego, U.Lindahl

Journal of Biological Chemistry  276(33),  30744  - 2001

Proteins that belong to the fibroblast growth factor (FGF) family regulate proliferation, migration, and differentiation of many cell types. Several FGFs, including the prototype factors FGF-1 and FGF-2, depend on interactions with heparan sulfate (HS) proteoglycans for activity. We have assessed tissue-derived HS fragments for binding to FGF-1 and FGF-2 to identify the authentic saccharide motifs required for interactions. Sequence information on a range of N-sulfated HS octasaccharides spanning from low to high affinity for FGF-1 was obtained. All octasaccharides with high affinity for FGF-1 (¦0.5 M NaCl required for elution) contained an internal IdoUA(2-OSO3)-GlcNSO3(6-OSO3)-IdoUA(2-OSO3)-trisaccharide motif. Octasaccharides with a higher overall degree of sulfation but lacking the specific trisaccharide motif showed lower affinity for FGF-1. FGF-2 was shown to bind to a mono-O-sulfated HS 6-mer carrying a single internal IdoUA(2-OSO3)-unit. However, a di-O-sulfated -IdoUA(2-OSO3)-GlcNSO3-IdoUA(2-OSO3)-trisaccharide sequence within a HS 8-mer gave stronger binding. These findings show that not only the no. but also the positions of individual sulfate groups det. affinity of HS for FGFs. Our findings support the notion that FGF-dependent processes can be modulated in vivo by regulated expression of distinct HS sequences.


425) Thermal Oxidation Products of Nylon 6 Determined by MALDI-TOF Mass Spectrometry

D.Chionna, C.Puglisi, F.Samperi, G.Montaudo, A.Turturro

Macromolecular Rapid Communications  22(7),  524  - 2001

Matrix-assisted laser desorption ionisation (MALDI) mass spectrometry was used, in an attempt to find firm evidence for the structure of the species produced in the thermal oxidative degradation of Nylon 6 (Ny6), at 250 degreesC in air. The MALDI spectra of the products showed the presence of polymer chains containing aldehydes, amides, methyl and N-formamide terminal groups. The aldehydes undergo further oxidation to produce carboxylic end groups. The formation fo azomethines, from the further reaction of aldehydes with amino-terminated Ny6 chains, is also supported by the appearance of specific peaks in the MALDI spectra


426) Identification of adulteration in milk by matrix-flight mass spectrometry

R.Cozzolino, S.Passalacqua, S.Salemi, P.Malvagna, E.Spina, D.Garozzo

Journal of Mass Spectrometry  36(9),  1031  - 2001

The development is described of a rapid, simply and accurate analytical method aimed at evaluating both the presence of cow milk in either raw ewe and water buffalo milk samples employed in industrial processes and the addition of powdered milk to samples of fresh raw milk, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The presence of adulteration is defined by evaluating the protein patterns coming from the most abundant whey proteins, alpha -lactalbumin and beta -lactoglobulin, used as molecular markers. As no pretreatment of the milk samples is required and owing to the speed and ease of use of MALDI-MS the proposed analytical protocol can be used as a routine strategy for the identification of possible adulteration of the raw fresh milk samples that the dairy industry receives from producers every day. Copyright © 2001 John Wiley & Sons, Ltd


427) The structure of a polysaccharide from infectious strains of Burkholderia cepacia

A.Linker, L.R.Evans, G.Impallomeni

Carbohydrate Research  335(1),  45  - 2001

The structure of an acidic exopolysaccharide (EPS) from eight strains of Burkholderia cepacia has been investigated by methylation and sugar analysis, periodate oxidation-Smith degradation, and partial acid-hydrolysis. An enzyme preparation obtained from the same organisms producing the EPS was also used to depolymerize the polysaccharide. Detailed NMR studies of the chemical and enzymatic degradation products showed that this EPS consists of a highly branched heptasaccharide-repeating unit with the following structure: [GRAPHICS] About three O-acetyl groups per repeating unit are present at undetermined positions. (C) 2001 Elsevier Science Ltd. All rights reserved


428) Biosynthesis and structural characterization of medium-chain-length Poly(3-hydroxyalkanoates) produced by Pseudomonas aeruginosa from fatty acids

A.Ballistreri, M.Giuffrida, S.P.P.Guglielmino, S.Carnazza, A.Ferreri, G.Impallomeni

International Journal of Biological Macromolecules  29(2),  107  - 2001

In this study, we investigated the ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize poly(3-hydroxyalkanoates) (PHAs) from saturated fatty acids with an even number of carbon atoms, from eight to 22, and from oleic acid. In a non-limiting medium, all carbon sources but docosanoic acid supported cell growth and PHA production, with eicosanoic acid giving the highest yield. In magnesium-limiting conditions, higher yields were obtained from sources with up to 16 carbon atoms. Composition was estimated by gas chromatography of methanolzyed samples and C-13 nuclear magnetic resonance. The 3-hydroxyalkanoate units extended from hexanoate to tetradecanoate or tetradecenoate, with octanoate and decanoate as the predominant components. Weight average molecular weights ranged from 78 000 to 316 000. Fast atom bombardment mass spectrometry of partially pyrolyzed samples, coupled to statistical analysis, showed that these PHAs are random copolymers. (C) 2001 Elsevier Science B.V. All rights reserved


429) Matrix-assisted laser desorpition/ionization mass spectrometric peptide mapping of high molecular weight glutenin subunits 1Bx7 and 1Dy7 in Cheyenne cultivar

R.Cozzolino, S.Di Giorgi, S.Fisichella, D.Garozzo, D.Lafiandra, A.Palermo

Rapid Communications in Mass Spectrometry  15(10),  778  - 2001

"This study describes the verification of the cDNA-deduced amino acid sequences of high molecular weight glutenin subunits 1Dy10 and 1Bx7 in Cheyenne cultivar by direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) analysis of their tryptic fragments omitting chromatographic pre-separation. These polypeptides have a conserved structure consisting of a long central repetitive domain that prevents the application of conventional sequencing procedures such as Edman degradation. The published sequence of subunit 1Dy10 contains 7 Lys and 13 Arg residues; thus the production of 21 tryptic peptides is expected. The cDNA-deduced sequence for 1Bx7 subunit includes 5 Lys and 15 Arg residues, but the presence of three Arg-Pro bonds, which are normally not cleaved by trypsin, predicts only 19 tryptic peptides. Three different matrices (DHB, SA and HCCA) in combination with the most compatible sample preparation procedures were used in order to obtain the maximum 1Dy10 and 1Bx7 sequence coverage. MALDI analysis of the 1Dy10 tryptic digest resulted in the identification of all 21 expected peptides. In the case of 1Bx7 MALDI analysis resulted in the identification of 17 of the 19 expected peptides, giving a sequence coverage of 99.3%. These results were sufficient to rule out glycosylation of the 1Dy10 and 1Bx7 proteins and to assess the absence of any other post-translational modification, to within the detection limits of the method. Copyright © 2001 John Wiley & Sons, Ltd"


430) Proteomics of gluten: mapping of subunit 1 Ax2* in Cheyenne cultivar by matrix-assisted laser desorption/ionization

R.Cozzolino, S.Di Giorgi, S.Fisichella, D.Garozzo, D.Lafiandra, A.Palermo

Rapid Communications in Mass Spectrometry  15(14),  1129  - 2001

This paper reports results on the verification of the 1Ax2* high molecular weight glutenin subunit sequence in Cheyenne cultivar. The gene sequence of the protein is known but recently some text changes have been made, and furthermore until now no characterization of post-translational modifications has been reported. The two published sequences, named I and II, differ in four residues at positions 23, 208, 475, and 611. The first sequence contains 20 Arg and 6 Lys residues, producing 26 tryptic fragments, since the Arg(109)-Pro(110) bond is generally not cleaved by trypsin. The second sequence contains 19 Arg and 6 Lys residues, producing 25 tryptic peptides, again because of the Arg(109)-Pro(110) bond. Both sequences generate two cyanogen bromide fragments. Matrix-assisted laser desorption/ionization analysis of the tryptic digest of the high-MW glutenin subunit 1Ax2* resulted in the identification of 24 out of the 26 expected peptides for sequence I, a sequence coverage of 99.5%. These results were sufficient to rule out sequence II and any protein glycosylation and any other post-translational modifications to within the detection limits of the method. It was found that the choice of matrix considerably influenced the sequence coverage in peptide mapping. Copyright © 2001 John Wiley & Sons, Ltd


431) Determination of the Compositional Distribution and Compositional Drift in Styrene/Maleic Anhydride Copolymers

M.S.Montaudo

Macromolecules  34(9),  2792  - 2001

A generally applicable method is used here to measure the weight of copolymer chains which possess a given mass and composition, i.e., to determine the bivariate distribution of chain sizes and composition in copolymers. The method consists of three steps. The copolymer is initially fractionated using size exclusion chromatography (SEC) and fractions are collected. The SEC fractions are analyzed by H-1 NMR to determine both the copolymer abundance and composition, and then by matrix-assisted laser desorption ionization mass spectrometry (MALDI) to determine the molar mass of each fraction. in the third step, bivariate distribution of chain sizes and composition maps are derived from knowledge of the molar mass, weight and composition of the copolymer fractions. The compositional distribution is obtained by summation of the sections of the bivariate distribution which belong to a narrow compositional range. The method was applied to two random copolymer samples containing units of styrene (St) and of maleic anhydride (MAH) reacted up to high conversion. Both samples had a strong compositional drift. At low masses, chains were rich in maleic anhydride, whereas at high masses chains were rich in styrene. The bivariate distribution was a smooth surface with a single maximum fbr both samples. Integration of the surface over narrow compositional ranges yielded the compositional distribution histogram. For one of the two samples, the histogram was relatively smooth and almost flat, whereas for the other sample the histogram was triangle-shaped with a discontinuity in the styrene-rich region


432) Bacterial pollution of Messina coastal waters: a one year study

G.Caruso, R.Zaccone, L.Monticelli, E.Crisafi, D.Zampino

New microbiologica  23(3),  297-304  - 2000

A year's monitoring of faecal pollution of marine coastal waters surrounding Messina was carried out in 1996/97. The distribution of faecal coliforms was evaluated in 15 stations located along the Sicilian coastline, sampled monthly in coincidence of the two opposing current phases ("montante" and "scendente" currents) which characterise the Straits of Messina. The data obtained provided a complete picture of hygienic-sanitary conditions of the area and highlighted the presence of heavily polluted sites in correspondence with river outflows. Higher bacterial counts were associated with lower salinity values and higher ammonia concentrations; over an annual study, they occurred during the coldest months, showing the negative impact of continental water inputs on the bacteriological quality of coastal waters.


433) Fluorinated phosphoric ester-based protective material for limestone-made ancient monuments, buildings, and artifacts: an x-ray photoelectron spectroscopy study

G.Spoto, P.Rizzarelli, A.Torrisi

Applied Spectroscopy  54(12),  1817  - 2000

In this study, fluorinated phosphoric esters are evaluated as protective material for limestone from water-driven alteration processes. Hypotheses as to their molecular arrangement are also provided. The surface composition of limestone after treatment with a commercially available fluorinated phosphoric ester material was evaluated by X-ray photoelectron spectroscopy (XPS). Results were then compared with those obtained for the treated limestone after accelerating aging test. In the limestone that had not been subjected to aging processes an XPS determined thickness of the protective coating equivalent to 95 ¦ 18 + was observed. This fell to 49 ¦ 10 + in the limestone examined after intensive aging tests. However, low surface wettability (q = 135¦ ¦ 4) was seen to be maintained.


434) Synthesis and enzymatic degradation of aliphatic copolyesters

G.Montaudo, P.Rizzarelli

Polymer Degradation and Stability  70(2),  305  - 2000

A series of high molar mass aliphatic homo- and copolyesters was obtained from 1,4-butanediol and dimethylesters of succinic, adipic and sebacic acids. These materials were characterised by H-1-NMR, SEC, DSC, X-ray and viscometry. Good filmability was achieved for all the polyesters. Film samples were subjected to enzymatic attack and the relative normalised weight loss rates were compared. The results indicate that the copolyesters have reduced crystallinity with respect to the homopolyesters, and that the rate of enzymatic degradation is increased when the sample crystallinity decreases. Furthermore, it was observed that structural changes in the repeat unit of the copolyesters affect the rate of enzymatic degradation, independent of sample crystallinity. Instead, molar mass changes in the polymer investigated do not affect the rate of enzymatic degradation. (C) 2000 Elsevier Science Ltd. All rights reserved


435) Sequence Distribution and Fragmentation Studies of Bacterial Copolyester Macromolecules: Characterization of PHBV Macroinitiator by Electrospray Ion-Trap Multistage Mass Spectrometry

G.Adamus, W.Sikorska, M.Kowalcuk, M.S.Montaudo, M.Scandola

Macromolecules  33(16),  5797  - 2000

Sequence distribution and chemical structure of mass-selected macromolecules of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, biopolyester macroinitiator obtained by partial alkaline depolymerization of natural PHBV containing 5 mol % of HV units was determined by electrospray ionization multistage mass spectrometry (ESI-MSn). On the basis of the ESI-MSn studies of PHBV individual;oligomers, the microstructure of this bacterial copolyester was assessed, starting from dimer up to the oligomer containing 22 repeat units, and the results obtained were compared with those described previously for other 'soft' ionization MS techniques


436) Inter-and intramolecular ester exchange reactions in the ring-opening polymerization of (D,L)-lactide using lanthanide alkoxide initiators

N.Spassky, V.Simic, M.S.Montaudo, L.G.Hubert-Pfalzgraf

Macromolecular Chemistry and Physics  201(17),  2432  - 2000

Polylactide samples obtained by the ring-opening polymerization of (D,L)-lactide by using different lanthanide alkoxide initiators were examined by SEC, C-13 NMR and MALDI-TOF MS techniques. The evidence of substantial transesterification was observed in the case of a polymerization initiated by lanthanum alkoxide and bimetallic aluminium-yttrium alkoxide initiators. In the case of Y and Sm alkoxide initiators, the MWD remains narrow up to high conversions for reasonable polymerization times, but the prolongation of the post-polymerization time increases the amount of ester-exchange reactions. The extent of the transesterification reactions was evaluated on the basis of the intensity of the stereosequence resonances for the methine carbon signal in the C-13 NMR spectra. MALDI-TOF MS analysis revealed the presence of odd-membered oligomers in all spectra. Thus, transesterification reactions occur from the beginning of the polymerization. Linear and cyclic oligomers were detected in some cases indicating the simultaneous occurrence of inter- and intramolecular exchange reactions. The microstructure analysis of the polymers by C-13 NMR spectroscopy indicates a preference for a syndiotactic addition during the polymerization process


437) Tween 20 and ITS Major Free Fatty Acids as Carbon Substrates for the Production of Polyhydroxyalkanoates in Pseudomonas aeruginosa ATCC 27853

G.Impallomeni, S.P.P.Guglielmino, S.Carnazza, A.Ferreri, A.Ballistreri

Journal of Polymers and the Environment  8(2),  97-102  - 2000

The ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize polyhydroxyalkanoates (PHAs) using Tween 20 as the sole carbon source was investigated. Tween 20 could support cell growth and PHA production. The polymer produced from Tween 20 was compared with those produced from its major free fatty acids components: lauric (C-12), myristic (C-14), and palmitic (C-16) acids. Gas-chromatographic analysis of methanolyzed samples and C-13-Nuclear Magnetic Resonance (NMR) showed that the PHAs obtained are composed of even carbon atoms 3-hydroxyalkanoates ranging from C-6 to C-14, with C-8 and C-10 as the predominant components. The nature the carbon sources used had little influence on the composition, but was found to be important in determining the average molecular weight, shorter chain fatty acids yielding higher molecular weight products. Fast Atom Bombardment-Mass Spectrometry (FAB-MS) of partially pyrolyzed samples, coupled to statistical analysis, showed that these PHAs are random copolymers


438) Structure of succinoglycan from an infectious strain of Agrobacterium radiobacter

L.R.Evans, A.Linker, G.Impallomeni

International Journal of Biological Macromolecules  27(5),  319  - 2000

The exopolysaccharide produced by a cystic fibrosis clinical isolate of Agrobacterium radiobacter was shown by monosaccharide and methylation analyses, degradation with succinoglycanase and NMR analysis to be a succinoglycan with the structure shown below. (S)-pyruvic acid is found stoichiometrically as 4,6-O-ketal substituent of terminal glucose. Succinic acid is present in 40% of the repeating units and it is attached to O-6 of the 3-linked glucose next to the pyruvate carrying sugar. Some evidence is found that a small amount of succinic acid (ca. 6% of the total) is linked to O-6 of another undetermined glucose. [GRAPHICS] (C) 2000 Published by Elsevier Science B.V


439) Structural Study of the Exopolysaccharide produced by a Clinical Isolate of Burkholderia cepacia

P.Cescutti, M.Bosco, F.Picotti, G.Impallomeni, J.H.Leitao, J.A.Richau, I.Sà-Correia

Biochemical and Biophysical Research Communications  273(3),  1088  - 2000

The primary structure of the exopolysaccharide produced by a clinical isolate of the bacterium Burkholderia cepacia was studied by means of methylation analysis, selective degradation, NMR spectroscopy, and electrospray mass spectrometry, The resulting data showed that the parent repeating unit of the exopolysaccharide is a highly branched heptasaccharide with the following structure: [GRAPHICS] Two acetyl groups are present per repeating unit, as noncarbohydrate substituents, (C) 2000 Academic Press


440) Preparation of Functionalized Copolymers by Thermal Processes: Porphyrination and fullerenation of Commercial Polycarbonate

D.Vitalini, P.Mineo, V.Iudicelli, E.Scamporrino, G.Troina

Macromolecules  33(20),  7300  - 2000

The preparation of copolycarbonates containing porphyrin or fullerene units in the main chain is described. The syntheses were performed inserting the 'special groups' in bisphenol A polycarbonate (PC) molecules by prolonged heating at 240 degrees C of PC mixtures with different amounts (5-30 wt %) of porphyrin or,fullerene derivatives. To this end, four porphyrins with one or two phenolic [5-(p-hydroxyphenyl)-10,15,20-tris(p-decanoxyphenyl)porphyrin (II) and 5,15-bis(p-hydroxyphenyl)-10,-20-bis(p-decanoxyphenyl)porphyrin (III)I or alcoholic [5-[p-(11-hydroxy)undecanoxyphenyl]-10,15,20-tris(p-dodecanoxyphenyl)porphyrin (TV) and 5,16-bis[p-(11-hydroxy)undecanoxyphenyl]-10,20-bis(p-dodecanoxyphenyl)porphyrin (V)]-OH groups and 61-(p-hydroxyphenyl)methano-1,2-fullerene[60] were prepared. Composition and structure of the obtained materials were inferred by GPC, UV-visible, and MALDI-TOF analysis. Our results suggest that thermal activated exchange reactions provoke a gradual and homogeneous porphyrination or fullerenation of the polymer chains in the entire mass range. It was also ascertained that, under our conditions, the outer-inner reactions produce only a moderate mass reduction of the PC


441) Matrix-assisted laser desorption/ionisation time-of-flight characterisation of biodegradable aliphatic copolyesters

S.Carroccio, P.Rizzarelli, C.Puglisi

Rapid Communications in Mass Spectrometry  14(16),  1513  - 2000

The preparation of copolycarbonates containing porphyrin or fullerene units in the main chain is described. The syntheses were performed inserting the 'special groups' in bisphenol A polycarbonate (PC) molecules by prolonged heating at 240 degrees C of PC mixtures with different amounts (5-30 wt %) of porphyrin or,fullerene derivatives. To this end, four porphyrins with one or two phenolic [5-(p-hydroxyphenyl)-10,15,20-tris(p-decanoxyphenyl)porphyrin (II) and 5,15-bis(p-hydroxyphenyl)-10,-20-bis(p-decanoxyphenyl)porphyrin (III)I or alcoholic [5-[p-(11-hydroxy)undecanoxyphenyl]-10,15,20-tris(p-dodecanoxyphenyl)porphyrin (TV) and 5,16-bis[p-(11-hydroxy)undecanoxyphenyl]-10,20-bis(p-dodecanoxyphenyl)porphyrin (V)]-OH groups and 61-(p-hydroxyphenyl)methano-1,2-fullerene[60] were prepared. Composition and structure of the obtained materials were inferred by GPC, UV-visible, and MALDI-TOF analysis. Our results suggest that thermal activated exchange reactions provoke a gradual and homogeneous porphyrination or fullerenation of the polymer chains in the entire mass range. It was also ascertained that, under our conditions, the outer-inner reactions produce only a moderate mass reduction of the PC


442) Sequencing of oligosaccharides by collision-induced dissociation matrix-assisted laser desorption/ionization mass spectrometry

E.Spina, R.Cozzolino, E.Ryan, D.Garozzo

Journal of Mass Spectrometry  35(8),  1042  - 2000

A study of the collision-induced dissociation post-source decay (PSD) spectra of free oligosaccharides is presented. These spectra, when obtained with helium as collision gas, show X-1,X-5 fragments containing the reducing end sugar. The presence of these fragments permits Y ions and, consequently, B and C peaks to be identified, This is a common behaviour from which it has been possible to delineate a general method for the easy assignment of the peaks in PSD spectra of underivatized neutral sugars, allowing the sequence of a real unknown to be obtained. Copyright © 2000 John Wiley & Sons, Ltd


443) Studies on the primary structure of short polysaccharides using SEC MALDI mass spectroscopy

D.Garozzo, E.Spina, R.Cozzolino, P.Cescutti, W.F.Fett

Carbohydrate Research  323(1-4),  139  - 2000

The introduction of size-exclusion chromatography (SEC) analysis of polysaccharides prior to MALDI mass spectroscopy accounts for the determination of the molecular mass of the repeating unit when neutral homopolymers are investigated. In the case of natural polysaccharides characterised by more complicated structural features (presence of non-carbohydrate substituents, charged groups, etc.), this mass value usually is in agreement with more than one sugar composition. Therefore, it is not sufficient to give the correct monosaccharidic composition of the polysaccharide investigated. To solve this problem, MALDI spectra were recorded on the permethylated sample and post-source decay experiments were performed on precursor ions. In this way, the composition (in terms of Hex, HexNAc, etc.), size and sequence of the repeating unit were determined. (C) 2000 Elsevier Science Ltd. All rights reserved


444) Introduction of a nitrogen heterocycle into sulfated chitosan oligomers

F.Santini, G.Crini, C.Cosentino, L.Sturiale, E.A.Yates

Journal of Carbohydrate Chemistry  18(1),  105  - 1999

The prepn. of an unusual deriv. of chitosan (I) oligomers contg. a N heterocycle, which was obtained by depolymn. of I in H2SO4 followed by a no. of sulfation steps to obtain persulfated I fragments, and treatment of the latter under strong basic conditions resulting in an unusual ring closure reaction to give an N-sulfonatoaxiridine-substituted product (II), is reported. The ring closure reaction involves internal nucleophilic attack at C-3 of the glucosamine ring by the N atom attached at C-2 to cause inversion of configuration at C-3, giving a D-allo configuration product with formation of an N-sulfonatoaziridine ring. The N at C-2 requires an N-sulfoamino group for the reaction to proceed under these conditions. The aziridine group in II is characterized by signals at high field in both proton and 13C spectra and large 1JCH coupling consts. at these positions.


445) In memory of Allan Maccoll - Personal tribute

G.Montaudo

European Journal of Mass Spectrometry  27,  308  - 1999



446) Synthesis of 5,5 '-bicalix[6]arene and 5,5 '-bicalix[8]arene systems

A.Bottino, F.Cunsolo, M.Piattelli, D.Garozzo, P.Neri

Journal of Organic Chemistry   64(21),  8018  - 1999



447) Thermal Decomposition Processes in Aromatic Polycarbonates Investigated by Mass Spectrometry

C.Puglisi, L.Sturiale, G.Montaudo

Macromolecules  32(7),  2194  - 1999

The thermal decomposition pathways leading to the formation of volatile compounds and to char residue in poly(bisphenol A carbonate) (PC), poly(resorcinol carbonate) (PRC), and poly-(hydroquinone carbonate) (PHC) have been investigated by mass spectrometry. The structure of the volatile compounds obtained in the temperature range 300-700 degrees C, by direct pyrolysis mass spectrometry (DPMS), suggests that these polycarbonates undergo thermal decomposition by a number of different pyrolysis processes. In the initial stage of the thermal degradation are generated cyclic oligomers by an intramolecular exchange reaction, whereas the evolution of CO2 and H2O is spread over all the pyrolysis temperature range, being responsible for the formation of ether bridges (decarboxylation) and phenolic end groups (hydrolysis). A disproportionation reaction of the BPA isopropylidene bridges of PC itself takes place at higher temperature yielding phenyl and isopropylidene end groups, whereas pyrolysis products containing dibenzofuran units are formed by dehydrogenation of ether units. The formation of compounds containing xanthone and fluorenone units, most likely generated by isomerization of the aromatic carbonate functional groups and successive condensation reaction, has also been observed. In an additional set of experiments, the isothermal pyrolysis of PC was achieved, isothermally, at 350 and 400 degrees C, and then the exhaustive and selective aminolysis of the carbonate functional groups, still present in the pyrolysis residue, has been performed. The aminolyzed residue was then analyzed by fast atom bombardment (FAB) mass spectrometry to detect the compounds eventually formed by molecular rearrangements of PC chains. The FAB-MS spectra showed the presence of compounds containing several consecutive xanthone and ether units, indicating that at this temperature the isomerization and the condensation processes leading to these structures are quite extensive. These units undergo aromatization and cross-linking processes, leading to a graphite-like charred residue as the temperature increases


448) Thermal Degradation mechanisms of Polyetherimide investigated by direct pyrolysis mass spectrometry

S.Carroccio, C.Puglisi, G.Montaudo

Macromolecular Chemistry and Physics  200(10),  2345  - 1999

"The thermal degradation mechanisms of poly[2,2'-bis(3,4-dicarboxyphenoxy)phenylpropane-2-phenylenediimide] (PEI) have been investigated by thermogravimetry (TG) and by direct pyrolysis mass spectrometry (DPMS). TG data show that PEI has a main decomposition step centred at about 510 degrees C followed by a less marked step in the 600-650 degrees C temperature range and leaving about 60% of chanted residue at 800 degrees C. The total ion curve (TIC) of a purified PEI sample, obtained by DPMS, closely reproduces the two maxima appearing in the derivative TG (DTG) curve, whereas the TIC curve of a crude PEI sample shows two less pronounced maxima in the temperature range of 250-450 degrees C due to low molar mass compounds, which volatilize undecomposed in the high vacuum of the MS. The structure of the pyrolysis compounds obtained in the first thermal degradation step of a purified PEI sample suggest that they are mainly formed by the scission of: i) the isopropylidene bridge of bisphenol A; ii) the oxygen-phthalimide bond; iii) the phe phenyl-phthalimide bond, which are apparently the weakest bonds of PEI. Extensive hydrogen transfer reactions and subsequent condensation reactions may account for the high amount of char residue. The pyrolysis compounds obtained in the second degradation step (620 degrees C) are mainly constituted of CO2 benzene, aniline, benzonintrile, phenylenediamine, and dibenzonitrile, which may he generated by further thermal degradation reactions of pyrolysis compounds containing N-H phthalimide as end groups. Another degradation processes which may account for CO2 formation is the hydrolysis of the imide moiety to form poly(amic acid) units which produce an aromatic amide structure by decarboxylation. The pyrolysis of an aromatic polyamide (NOMEX) was then studied for comparison. The structure of the pyrolysis products detected by the DPMS analysis of both polymers allowed a detailed schematization of the thermal degradation pathways involved in the degradation of PEI and on the reactions leading to the formation of the charred residue"


449) Bivariate Distribution of PMMA/PBA Copolymers by Combined SEC/NMR and SEC/MALDI

M.S.Montaudo, G.Montaudo

Macromolecules  32(21),  7015  - 1999

High conversion copolymers may experience a strong variation in composition as a function of monomer conversion, and since the compositional heterogeneity of copolymers varies as the size of the chains grows, this poses a problem in determining the bivariate distribution of masses and composition in copolymers. Although several methods have been proposed to determine bivariate distributions, relatively little data are available on this important aspect of copolymer characterization, perhaps because of the complexity of the methods available up to the present time. We propose here a generally applicable method to determine bivariate distribution of masses and composition in copolymers. SEC fractionation of two random copolymers, poly(methyl methacrylate)/polybutyl acrylate (PMMA/PBA) obtained at high and low conversions, respectively, was used to collect nearly monodisperse fractions that allowed the computation of the corresponding molar masses (by matrix-assisted laser desorption ionization mass spectrometry, MALDI, measurements) and of compositions (by NMR measurements) for the two copolymers. Bivariate distribution maps were derived by combining SEC/NMR and SEC/MALDI data with Stockmayer's theoretical distribution to estimate the composition distribution of each fraction


450) Maldi-Tof Investigation of Polymer Degradation. Pyrolysis of Poly(Bisphenol A Carbonate)

C.Puglisi, F.Samperi, S.Carroccio, G.Montaudo

Macromolecules  32(26),  8821  - 1999

The MALDI-TOF technique allows the detection of intact polymer molecules up to high masses and therefore offers the opportunity to study directly the thermal degradation processes occurring in polymeric materials by analyzing conveniently exposed (i.e., partially degraded) polymer samples. This opens new vistas in polymer analysis and deserves careful exploration, due to the relevance of polymer degradation phenomena in everyday practice. The thermal decomposition of poly(bisphenol A carbonate) (PC) has been investigated by heating isothermally at 300, 350, 400, and 450 degrees C and subsequent analysis of the pyrolysis residue by means of MALDI mass spectrometry. The MALDI mass spectra of the pyrolysis residues obtained at 300 degrees C showed a progressive reduction of the abundance of cyclic oligomers, whereas the relative abundance of the other compounds was unaffected. At 350 degrees C, the occurrence of an extensive hydrolysis reaction was responsible for the degradation of cycles and linear chains bearing tert-butylphenyl carbonate end groups with subsequent formation of abundant open chain PC oligomers with phenol end groups. Furthermore, at these two temperatures, cyclic oligomers never disappear in the MALDI spectra, even at higher heating time (60 min), suggesting the presence of an equilibrium between the rate of cleavage and the rate of formation of cycles. PC chains terminated with phenol groups at both ends, together with pyrolyzed chains bearing phenyl and isopropylidene end groups, generated by the disproportionation of the aliphatic bridge of bisphenol A, were observed in the MALDI spectra of pyrolysis residue obtained at 400 degrees C. Condensed aromatic compounds such as xanthones, which are considered to be the precursors of a graphite-like structure of the charred residue, were also detected in the MALDI spectra of PC samples heated at 400 degrees C and they became the most intense species at 450 degrees C. The PC samples heated at temperature higher than 450 degrees C consisted of insoluble carbonaceous materials not suitable for MALDI analysis


451) Analysis of Poly(Bispheno A Carbonate) by Size Exclusion Chromatography/Matrix-assisted Laser Desorption/Ionization.1.End Group and Molar Mass Determination

C.Puglisi, F.Samperi, S.Carroccio, G.Montaudo

Rapid Communications in Mass Spectrometry  13(22),  2260  - 1999

The determination of molar mass (MM) data for polydisperse polymers by SEC/MALDI involves the fractionation of samples through analytical size exclusion chromatography (SEC). Selected SEC fractions are then analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and the mass spectra of these nearly monodisperse samples allow the determination of the average molar masses, The SEC/MALDI procedure has now been applied to two polycarbonate samples, PC1 and PC2, The results show that the MALDI spectra of the SEC fractions allow not only the detection of linear and cyclic oligomers contained in these samples, but also the simultaneous determination of their average molar masses. Two slightly differing SEC calibration plots were obtained, due to the smaller hydrodynamic volume of the polycarbonate cyclic chains with respect to the linear ones, In agreement with theory, the ratio (M-cycle/M-linear)v(e) at a fixed elution volume was found to be 1.22, independent of the molar mass values, Copyright © 1999 John Wiley & Sons, Ltd


452) Analysis of Poly(Bispheno A Carbonate) by Size Exclusion Chromatography/Matrix-assisted Laser Desorption/Ionization.2.Self-association Due to Phenol End Groups

C.Puglisi, F.Samperi, S.Carroccio, G.Montaudo

Rapid Communications in Mass Spectrometry  13(22),  2268  - 1999

We report here a case of apparent failure of the size exclusion chromatography/matrix-assisted laser desorption/ionization (SEC/MALDI) method to provide polymer fractions with narrow molar mass distribution, showing that intermolecular chain association is responsible for this phenomenon, Poly(bisphenol A carbonate) (PC) chains terminated with hydroxyl groups undergo self-association by hydrogen bonding, providing macromolecular aggregates with higher hydrodynamic volume. These aggregates are eluted through SEC columns at the same volume as higher molar mass chains, which remain non-associated. Thus, self-association affects negatively the SEC fractionation experiments, and even the sharpest SEC fractions contain a heterogeneous mixture of PC chains of different size. When the off-line SEC/MALDI procedure is applied, the SEC fraction is diluted in the matrix which, being a dissociating medium (carboxylic acid) for hydrogen-bonded aggregates, suppresses the chains' self-association. Therefore, the MALDI spectra of these PC fractions indicate a polydisperse character, with irregular bimodal distributions of peaks, As a consequence, in the presence of chain association, the SEC/MALDI method for the calculation of molar masses of polymers cannot be directly applied. In the present case we have found that, under opportune experimental conditions, self-association in polycarbonates can be avoided, so that nearly monodisperse SEC fractions can be obtained and the SEC/MALDI method can be applied, Our results also show that MALDI is a very sensitive technique for the detection of association of polymers in dilute solutions. Copyright © 1999 John Whey & Sons, Ltd


453) Use of Hydroxyacetophenones as Matrices for the Analysis of High Molecular Weight Glutenin Mixtures by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

D.Garozzo, R.Cozzolino, S.Di Giorgi, S.Fisichella, D.Lafiandra

Rapid Communications in Mass Spectrometry  13(21),  2084  - 1999

A selection of hydroxyacetophenones has been investigated as matrices for the analysis, by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), of high molecular weight (HMW) glutenin mixtures from three wheat varieties. Mass spectra were obtained directly from the HMW glutenin extracts without any preliminary purification and separation steps. According to the quality of the mass spectra, obtained using different hydroxyacetophenones, it has been possible to classify the matrices on the basis of their suitability for the analyte properties. Only two of the matrices considered showed to be compatible with the HMW glutenin mixtures analysis, although a large amount of other highly complex protein mixtures are present, This study indicates that MALDI-MS, as a stand-alone technique, Is particularly useful for the direct determination of the complete HMW subunits profile and their molecular weights, Copyright © 1999 John Wiley & Sons, Ltd


454) Synthesis of aliphatic polyester by controlled ring-opening polymerization of cyclic esters. Characterization properties transesterification reactions

N.Spassky, V.Simic, L.G.Hubert-Pfalzgraf, M.S.Montaudo

Macromolecular Symposia  144,  257  - 1999

The polymerization of (D,L)-Lactide at room temperature in solution using Y(OCH(2)CH(2)OiPr)(3) and Ln(5)(mu-O)(OiPr)(13) with Ln = La, Sm, Y, Yb as initiators was studied. According to kinetic data, a controlled type polymerization is observed for most of the systems. La mu-oxoisopropoxide is the mast reactive initiator, but leads to a substantial broadening of molecular weight distribution at high conversions. The nature of transesterification reactions was studied by SEC, C-13 NMR and MALDI-TOF MS techniques. For Sm and Y-mu-oxo initiators only limited intermolecular ester exchange occurs, while with La mu-oxoinitiator and with Y(OCH(2)CH(2)OiPr)(3) initiator, but after a long time of the polymerization reaction, both inter and intramolecular transesterification occur with formation of cyclics


455) Characterization by mass spectrometry of poly(3-hydroxyalkanoates) produced by Rhodospirillum rubrum from 3-hydroxyacids

A.Ballistreri, M.Giuffrida, G.Impallomeni, R.W.Lenz, R.C.Fuller

International Journal of Biological Macromolecules  26(2-3),  201  - 1999

The sequence distributions of two microbial copolyesters obtained by fermentation of Rhodospirillum rubrum, grown with 3-hydroxyhexanoic or 3-hydroxyheptanoic acids, were determined by analyzing the oligomers prepared by partial pyrolysis or partial methanolysis of these copolyesters using fast atom bombardment mass spectrometry (FAB-MS). Oligomers up to pentawers were identified in the case of partial pyrolysis and up to tetradecamers in the case of partial methanolysis. The comparison between the experimental and calculated peak intensities of FAB mass spectra allows the calculation of compositions and sequence distributions, which in these copolyesters follow Bernoullian statistics, indicating that they are random terpolyesters. (C) 1999 Elsevier Science B.V. All rights reserved


456) Effect of Combined Changes in Delayed Extraction Time and Potential Gradient on the Mass Resolution and Ion Discrimination in the Analysis of Polydisperse Polymers and Polymer Blends by Delayed Extraction Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

D.Vitalini, P.Mineo, E.Scamporrino

Rapid Communications in Mass Spectrometry  13(24),  2511  - 1999

Data reported here show that, in the delayed extraction matrix-assisted laser desorption/ionization time-of-flight (DE-MALDI-TOF) mass spectrometric analysis of synthetic polydisperse polymers, different experimental conditions of spectral recording are required to optimize the signal in all the m/z regions of the spectrum. The effect of combined changes in delay time and grid voltage % values on both mass resolution and mass accuracy of DE spectra of a polyethylene glycol sample (PEG(mix), with a well-defined molar distribution of its components) is discussed. The necessity of a compromise between the values of these two parameters is shown, Furthermore, the occurrence of analyte discrimination, which can invalidate the composition analysis especially in the case of polymer blends, is demonstrated.


457) Synthesis and Characterization of Some Copolyformals Containing, in The Main Chain, Different Amounts of Fullerene Units

E.Scamporrino, D.Vitalini, P.Mineo

Macromolecules  32(13),  4247  - 1999

"Two fullerene monomers, 61,61'-bis(p-hydroxyphenylmethano)fullerene[60] (I) and 61,61-bis(p-hydroxyphenyl)methano-1,2-fullerene [60] (II) were prepared. Polycondensations between dibromomethane and suitable mixtures of I or II and bisphenol A or 1,20-di(bisphenoxy-A)eicosane (III) in different molar ratios were performed to obtain copolyformals IV-VII that contain up to about 5% (molar) of fullerene units in the main chain. Composition and microstructure of these copolyformals were inferred by UV-visible and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analyses. Copolymers IV-VII are soluble enough materials and exhibit a good thermal stability; besides, the insertion of long linear aliphatic linkages along the main chain of copolyformals VI and VII produces a remarkable lowering in their glass transition temperature at about 15 degrees C"


458) Synthesis and Characterization of Some Main Chain Porphyrin Copolyformals, Based on Bisphenol A and Long Linear Aliphatic Units, Having a Low Glass Transition Temperature

D.Vitalini, P.Mineo, E.Scamporrino

Macromolecules  32(1),  60  - 1999

The synthesis of new high molecular mass copolyformals containing long linear aliphatic linkages and different amounts of porphyrin units in the main chain is described. The copolymers have been prepared by the condensation reaction between a large excess of dibromomethane and mixtures of 1,12-dodecanedi(bisphenol A) ether (I) or 1,20-eicosanedi(bisphenol A)ether (II) and 5,10-bis(p-hydroxyphenyl)-15,20-bis(p-dodecanoxyphenyl)por (III) in different molar ratio. The structural characterization of the resulting copolyethers has been performed by NMR and MALDI-TOF analysis. The average molecular mass values of the copolyethers determined by GPC have been compared with those obtained by a recently developed off-line procedure of MALDI-TOF mass spectrum processing. Thermal properties of copolymers have also been examined. All collected data show that high molecular mass copolymers with a homogeneous arrangement of the porphyrin and aliphatic units along the molecular chains and with a glass transition temperature depending on the aliphatic content in the molecules have been obtained


459) Recent Advances in the Analysis of Polymers and Copolymers by Mass Spectrometry

M.S.Montaudo

Macromolecular Symposia  141,  95  - 1999



460) Sequence Constraints in a Glycine-Lactic Acid Dopolymer Determined by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

M.S.Montaudo

Rapid Communications in Mass Spectrometry  13(8),  639  - 1999



461) Analysis of Human Serum Albumin variants by mass spectrometry procedures

A.Amoresano, A.Andolfo, R.A.Siciliano, R.Cozzolino, L.Minchiotti, M.Galliano, P.Pucci

Biochimica et Biophysica Acta-Protein Structure and Molecular Enzymology  1384,  79  - 1998

A new strategy for the structural characterization of human albumin variants has been developed which makes extensive use of mass spectrometric methodologies. The rationale behind the method is to provide a rapid and effective screening of the entire albumin structure. The first step in this strategy consists in the attempt to det. the accurate mol. mass of the intact variant by electrospray mass spectrometry often providing a first indication on the presence of the variant. An HPLC procedure has been developed to isolate all the seven fragments generated by CNBr hydrolysis of HSA in a single chromatog. step. A rapid screening of the entire albumin structure is achieved by the ESMS anal. of the peptide fragments and the protein region(s) carrying the structural abnormality is identified by its anomalous mass value(s). Mass mapping of the corresponding CNBr peptide, either by Fast Atom Bombardment Mass Spectrometry (FABMS) or by Matrix Assisted Laser Desorption Ionisation Mass Spectrometry (MALDIMS), leads to the definition of the site and the nature of the variation. This combined strategy was applied to the structural characterization of three HSA genetic variants and provided to be an effective procedure for the rapid assessment of their structural modifications showing considerable advantages over the classical approach.


462) A comparative study of two isoforms of laccase secreted by the white-rot fungus Rigidoporus Lignosus, exhibiting significant structural and functional differences

R.P.Bonomo, A.M.Boudet, R.Cozzolino, E.Rizzarelli, A.M.Santoro, R.Sterjiades, R.Zappalà

Journal of Inorganic Biochemistry  71(3),  205  - 1998

Two isoforms of laccase were obtained as the predominant phenol oxidases in defined-medium liq. cultures of the white-rot fungus, R. lignosus. A characterization of the 2 laccases was made in terms of mol. wt., pI, metal content and N-terminal sequence. Furthermore, in order to gain information on the structural features related to the metal centers, a study of their geometric arrangement and their redox ability was made. It was found that the 2 isoforms differed greatly with respect to pH stability, catalytic, and Cu center features. It was proposed that all such differences were dependent on the amino acid sequences, which cause a distortion of the Cu sites, thus accounting for the redox potential values and kinetic properties.


463) Mechanism of Exchange in BPT/PC and PET/PC Blends.Composition of the Copolymer Formed in the Melt Mixing Process

G.Montaudo, C.Puglisi, F.Samperi

Macromolecules  31(3),  650  - 1998

Mechanisms operating in the exchange reactions occurring in the melt mixing processes of Bisphenol A polycarbonate (PC) with poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) blends have been investigated making use of appropriate polymer samples, capped or containing reactive chain end groups. The exchange process may proceed by two different mechanisms: a direct exchange reaction between inner functional groups located inside the polymer chains, i.e., inner-inner, or by attack of reactive chain ends functional groups (outer) on inner groups, i.e., outer-inner. It is shown that the distinction between the two processes can be conveniently made by determining the composition of the copolymer formed in the exchange reaction. The inner-inner mechanism occurs only in the reaction between end-capped or high molar mass PET/PC or PET/PC samples, and it was found that the molar composition of the copolymer formed is always equal to the feed ratio of the two homopolymers and independent from the reaction time. The outer-inner mechanism occurs in the presence of hydroxyl or carboxyl reactive chain ends in PBT and PET samples. The reaction proceeds by the attack of the reactive end groups on the PC chains, originating block copolymers of PC and PBT and low molar mass PC with phenol end groups which are unreactive. The reaction stops right after the reactive end groups are consumed. The amount and the composition of the copolymers generated in the reactions are found to be constant as a function of time. The copolymer composition shows an excess of PBT or PET units with respect to the feed molar ratio. These results indicate that monitoring the composition of the copolymer formed in each case is diagnostic for establishing the mechanism of the reaction. The approach used here allows control of the composition and yield of the copolymer to be produced, and it is applicable to other systems where exchange reactions occur. [References: 32]


464) Molar Mass Distributions and Hydrodynamic Interactions in Random Copolyesters investigated by Size Exclusion Chromatography / Matrix Assisted Laser Desorption Ionization

M.S.Montaudo, C.Puglisi, F.Samperi, G.Montaudo

Macromolecules  31(12),  3839  - 1998

Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) was used in combination with size exclusion chromatography (SEC) to characterize a series of copolyesters with butylene adipate (BA), butylene succinate (BSu), and butylene sebacate (BSe) units. These copolyesters, synthesized by condensation polymerization from 1,4-butanediol and dimethyl esters, have flexible chains, are random, and do possess a homogeneous composition. The SEC fractionation of these polymers allowed to collect numerous fractions that were then analyzed by MALDI-TOF. The mass spectra of these nearly monodisperse fractions allowed the computation of the corresponding molar masses (MM). The calibrated SEC traces could then be used to compute average MM and molar mass distribution of the unfractionated samples. Furthermore, the SEC/MALDI data allowed an estimate of the effect of the hydrodynamic interactions of comonomers A and B along the copolymer chain and a comparison with the theoretical predictions. Sensible deviations from the simple additivity have been found for the four copolymers studied. [References: 17]


465) Chemical Reactions Occurring in the Thermal Treatment of PC/PMMA Blends

G.Montaudo, C.Puglisi, F.Samperi

Journal of Polymer Science part A: Polymer Chemistry  36,  1873  - 1998

The chemical reactions occurring in the thermal treatment of bisphenol-A polycarbonate( PC) and poly(methyl methacrylate) (PMMA) blends have been investigated by nuclear magnetic resonance (NMR), mass spectrometry (MS), size exclusion chromatography (SEC), and thermogravimetry (TG). Our results suggest that in the melt-mixing of PC/PMMA blends, at 230 degrees C, no exchange reactions occur and that only the depolymerization reaction of PMMA has been observed. In the presence of an ester-exchange catalyst (SnOBu2), an exchange reaction was found to occur at 230 degrees C, but no trace of PC/PMMA graft copolymer has been observed. Instead, an exchange reaction between the monomer methyl methacrylate (MMA), generated in the unzipping of PMMA chains, and the carbonate groups of PC has been suggested. This is due to the diffusion of MMA.at the interface or even into the PC domains, where it can react with PC producing law molar mass PC oligomers bearing methacrylate and methyl carbonate chain ends and leaving the undecomposed PMMA chains unaffected. The TG curves of PC/PMMA blends prepared by mechanical mixing and by casting from THF show two separated degradation steps corresponding to that of homopolymers. This behavior is different from that of a transparent film of PC/PMMA blend, obtained by solvent casting from DCB/CHCl3, which shows a single degradation step indicating that the degradation rate of PC is increased by the presence of PMMA in the blend. The thermal degradation products obtained by DPMS of this blend consist of methyl methacrylate (MMA), cyclic carbonates arising from the degradation of PMMA and PC, respectively, and a series of open chain bisphenol-A carbonate oligomers with methacrylate and methyl carbonate terminal groups. The presence of the latter compounds suggests a thermally activated exchange reaction occurring above 300 degrees C between MMA and PC. The presence of bisphenol-A carbonate oligomers bearing methyl ether end groups, generated by a thermally activated decarboxylation of the methyl carbonate end groups of PC, has also been observed among the pyrolysis products. © 1998 John Wiley & Sons, Inc. [References: 31]


466) Application of Size Exclusion Chromatography Matrix - assisted Laser Desorption/Ionization Time-of-flight to the Determination of Molecular Masses in Polydisperse Polymers

M.S.Montaudo, G.Montaudo, C.Puglisi, F.Samperi

Rapid Communications in Mass Spectrometry  12(9),  519  - 1998

The determination of molecular mass (MM) data for polydisperse polymers by size exclusion chromatography matrix assisted laser desorptinn/ionization time-of-flight (SEC/MALDI-TOF) involves the fractionation of samples through an analytical SEC. Selected fractions are then analysed by MALDI-TOF and the mass spectra of these nearly monodisperse samples allow the determination of M-n and M-w averages. To test the reliability of the molecular mass estimates by the SEC/MALDI-TOF method, a sample of polymethylmethacrylate (PMMA), two samples of polydimethylsiloxane (PDMS), and four samples of copolyesters, all polydisperse, were analysed. The results show that the molecular mass values of PMMA fractions obtained by MALDI-TOF are coincident with those obtained using the SEC calibration plots obtained with anionic PMMA standards. In the case of the two polydimethylsiloxanes (PDMS1 and PDMS2: linear and cyclic, respectively), two slightly differing SEC calibration plots were obtained, reflecting the different structures of the polymer chains of the two samples. The SEC traces of four copolyesters were obtained in tetrahydrofuran and CHCl3. Data on MM, MM distribution solvent effects and copolymer composition are reported. © 1998 John Wiley & Sons, Ltd. [References: 20]


467) Partially Selective Methanolysis of Sebacic Units in Biodegradable Multicomponent Copolyesters

M.S.Montaudo, G.Montaudo, C.Puglisi, F.Samperi

Macromolecular Rapid Communications  19(9),  445  - 1998

The composition and molar masses of equimolar multicomponent copolyesters, obtained from 1,4-butandiol and mixtures of succinic, adipic. sebacic, and terephthalic acids were characterized by C-13 NMR, size exclusion chromatography (SEC), matrix assisted laser desorption ionization-time of flight mass spectroscopy (MALDI-TOF-MS), and viscosimetry. These copolyesters were subjected to partial methanolysis, and the composition and sequence of the oligomers obtained in the methanolysis were determined by the analysis of their fast atom bombardment (FAB-MS) mass spectra. The comparison of the composition data obtained by FAB-MS and C-13 NMR indicates that for copolymers containing sebacic units the methanolysis is a partially selective process, and that oligomers containing sebacic units accumulate in the residue. [References:19]


468) An expert system for the interpretation of Pyrolysis mass spectra of condensation polymers

C.G.Georgakopoulos, M.Statheropoulos, G.Montaudo

Analytica Chimica Acta  359(1-2),  213  - 1998

The PROLOG programming language was used for the construction of the Expert System (ES) HEPHESTUS used in the interpretation of pyrolysis mass spectra of condensation polymers, such as polyamides, polycarbonates, polyethers, polyesters, polyureas, polyurethanes, polyimides, polysulphides, polysulfones, polyschiff bases, polysiloxanes and polyphosphagenes. The ES can be applied to Pyrolysis Mass Spectrometry (PyMS) spectra of polymers using Electron Impact, Chemical Ionisation or Desorption Chemical Ionisation modes. The sample is introduced and pyrolysed directly in the source of the mass spectrometer. The ES knowledge base is organised in a tree form, based on polymer structures. The inference mechanism uses empirical algorithms and the autocorrelation algorithm to determine important information present in the unknown polymer spectrum. Possible solutions are proposed using the Certainty Factor model and based on the rules of the knowledge base. The autocorrelation algorithm, used to determine the repeating unit, gave 57.3% of successes and 42.7% not best choices. Among the not best choices the 23.3% were failures. For the same purpose, the empirical algorithm gave 68.5% successes and 31.5% not best choices (among them 35.7% were failures). User interaction improves the ES's performance to propose the correct polymer (94.4% of the trials were the best choices). (C) 1998 Elsevier Science B.V. [References: 25]


469) Pyrolysis Pathways of Polyethers and a Method for the Interpretation of their Pyrolysis Mass Spectra of Polyethers

C.G.Georgakopoulos, M.Statheropoulos, G.Montaudo

Polymer Degradation and Stability  61(3),  481  - 1998

The pyrolysis pathways of polyethers are described. A method, which is based on these pathways, is proposed for the interpretation of pyrolysis mass spectra of polyethers. The method makes use of pyrolysis data organised in tables, which relate polyether structures with specific masses and mass series. The proposed method can be applied for most types of pyrolysis spectra, such as electron impact, chemical ionisation, field desorption and direct chemical ionisation. Examples of application of the method are presented and discussed. (C) 1998 Elsevier Science Limited. All rights reserved. [References: 29]


470) Structural Characterization of Multicomponent Copolyesters by Mass Spectrometry

M.S.Montaudo, C.Puglisi, F.Samperi, G.Montaudo

Macromolecules  31(25),  8666  - 1998

The structural characterization and composition of five random copolyesters, originating from 1,4-butanediol and mixtures of succinic, adipic, sebacic, and terephthalic acids, were obtained by analysis of their fast atom bombardment (FAB) and their matrix-assisted laser desorption ionization (MALDI) mass spectra. Multicomponent condensation copolymers may sometimes prove difficult to characterize by conventional techniques, whereas mass spectrometry is able to handle them. Once the choice between Bernoullian or Markoffian models has been made, the determination of copolymer composition, number-average sequence length, and related quantities can be achieved by applying well-defined analytical equations. The theoretical mass spectra of multicomponent copolymers are remarkably simple, and the number of peaks appearing in each copolymer mass spectrum is easily predictable. Different kinds of spectral fitting algorithms may help in the actual computations, and it has been shown that the apparent complexity of mass spectra of copolymers is due to the presence of mass series bearing different end groups. By selecting a single mass series, one obtains an experimental spectrum immediately comparable to the theoretical one. Detailed examples, together with a discussion on the reliability of results, are given to apply the computation procedures and to gain proper understanding of the concepts involved


471) Determination of sequence and composition in poly(butyleneadipate-co-butyleneterephthlate)by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

M.S.Montaudo, F.Samperi

European Journal of Mass Spectrometry  4(6),  459  - 1998

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used here for the analysis of an unfractionated copolymer sample of poly(butyleneadipate-co-butyleneterephthalate) (PBA/PBT). This is our first report on unfractionated samples, since previous studies by MALDI-TOF MS have concerned copolymer fractions. Mass-resolved peaks are seen up to 8000 Da, The peaks are due to oligomers which have a methylester and an hydroxy as end groups (CH3O/OH), which desorb by uptake of a sodium cation. We compared the intensity of mass spectral peaks with the theoretical intensities generated using a Bernoullian distribution of sequences. The composition which gives the best match was searched by the MACO4 program and a value of 49/51 in favor of terephthalic units was found, in excellent agreement with the composition derived from the H-1 NMR data


472) On the presence of 4-o-(1-carboxyethyl)-mannose in the capsular polysaccharide of Rhodococcus equi serotype 3

G.Impallomeni

Carbohydrate Research  312(3),  153  - 1998

4-O-[(S)-1-carboxyethyl]-D-mannose and 4-O-[(R)-1-carboxyethyl]-D-mannose were synthesized and their acetylated lactones (1) and (2) prepared and characterized by 1 and 2D NMR spectroscopy and mass spectrometry. NMR spectra of (1) were identical to those of the lactone of a monosaccharide isolated from the exocellular polysaccharide of the cyanobacterium Cyanospira capsulata. The same derivative of a monosaccharide isolated from the capsular polysaccharide of Rhodococcus equi serotype 3, identified as 4-O-[(S)-1-carboxyethyl]-D-mannose [W. B. Severn and J. C. Richards, Can. J. Chem., 70 (1992) 2664-2676], shows instead NMR spectra different from those of both lactones (1) and (2). This proves that 4-O-(1-carboxyethyl)-mannose is not among the constituent sugars of R. equi capsular polysaccharide. As a consequence, the nature of the sugar obtained from R. equi must be reinvestigated. (C) 1998 Elsevier Science Ltd. All rights reserved


473) A New Procedure for Detector Response Correction in MALDI - TOF Mass Spectral Analysis

E.Scamporrino, P.Maravigna, D.Vitalini, P.Mineo

Rapid Communications in Mass Spectrometry  12(10),  646  - 1998

A simple procedure for the correction of the decreasing detection response in a Matrix-assisted laser desorption/Ionization time-of-flight (MALDI-TOF) mass spectrum with increasing ion mass is reported. On the basis of the experimental MALDI-TOF mass spectrum of a mixture of four polymethylmethacrylate (PMMA) standards (molecular masses in the range 4-100 kDa), present in equal molar abundance, an equation describing the MALDI-TOF response has been derived. This equation has been used to correct any subsequently recorded MALDI spectrum. As an example, the procedure has been applied here to normalize the MALDI-TOF mass spectrum of a 1,20-di(bisphenoxy-A)eicosane based copolyformal (I) containing porphyrin units in the main chain. © 1998 John Whey & Sons, Ltd


474) A Scientific Approach for Cultural Heritage Preservation Case Study of Vandalistic acts on Important Roman Mosaics.

E.Ciliberto, G.Spoto, M.Matteini, C.Puglisi

Journal of Chemical Education  75(10),  1302  - 1998

As an example of the way in which a scientific study can help the restorer in the restoration of important artistic works, the authors report the case study of vandalistic acts on important Roman mosaics. On the night of September 29, 1995, some unknown vandals poured dark brown paint over several of the most beautiful and important mosaics of the Villa del Casale (Piazza Armerina, Italy). The villa, consisting of an extensive network of rooms, galleries, courtyards, and baths, contains some of the largest and most beautiful mosaics surviving from Roman times. Chemical investigations were performed in order to draw up a rapid restoration plan aimed at identifying the substances used and proposing a correct restoration procedure. A multitechnique, analytical approach was used for these investigations because of the highly complex heterogeneity of the materials studied. The results showed that toluidine red was present in the paint as pigment and that the vehicle was made up of a mixture of alkyd resins, together with styrenated compounds and unsaturated long chain-containing oils. Moreover, besides compounds like calcium carbonate, barium sulfate, and aluminum oxide, silver-containing compounds were present in the paint. All of these observations allowed the authors to propose the removal method to be adopted that achieved the restoration of the mosaics.


475) The structure of exocellular polysaccharide from the Cyanobacterium Cyanospira capsulata

D.Garozzo, G.Impallomeni, E.Spina, L.Sturiale

Carbohydrate Research  307(1-2),  113  - 1998

The exocellular polysaccharide produced by the cyanobacterium Cyanospira capsulata has been subjected to partial acid hydrolysis and N-deacetylation-nitrous acid deamination. The oligosaccharides released have been isolated by weak anion exchange and aqueous size exclusion chromatography, and characterized by a combination of 1D and 2D nuclear magnetic resonance spectroscopy, mass spectrometry, sugar compostion and linkage analyses. The polysaccharide has an octasaccharide repeating unit with the following structure: [GRAPHICS] (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 29]


476) Laser desorption/ionization of fluorinated fullerenes

R.Cozzolino, O.Belgacem, T.Drewello, L.Kasemberg, R.Herzschuh, S.Suslov, O.V.Boltalina

European Journal of Mass Spectrometry  3(6),  407  - 1997

Laser desorption/ionization time-of-flight (LDI-TOF) mass spectrometry was applied to fluorinated fullerene samples of varying F content. The formation of pos. and neg. charged ions from highly fluorinated fullerenes is discussed in comparison with earlier desorption expts. The neg.-ion LDI mass spectra of fluorofullerenes with different F content are contrasted with the mol.-ion region of spectra obtained under electron impact conditions. A complementary approach to study the formation and fragmentation features of anions involves matrix-assisted LDI-reflectron TOF mass spectrometry and liq. secondary ion mass spectrometry in conjunction with high-energy collisions utilizing a 4-sector tandem mass spectrometer.


477) A new syringopeptin produced by a Pseudomonas Syringae PV. Syringae strain isolated from diseased twigs of laurel

A.Scaloni, L.Camoni, D.Di Giorgio, M.Scortichini, R.Cozzolino, A.Ballio

Physiological and Molecular Plant Pathology  51(4),  259  - 1997

A new syringopeptin was purified from a culture of Pseudomonas syringae pv. syringae NCPPB 3869 isolated from laurel and its structure deduced by mass spectrometry and Edman degrdn. It differs from syringopeptin 25A only for the C-terminal amino acid residue, which is Phe instead of Tyr. The phytotoxicity and some other biol. activities of the new metabolite are comparable to those of syringopeptin 25A.


478) Molecular Weight Determination and Structural Analysis in Polydisperse Polymers by Hyphenated Gel Permeation Chromatography/Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

International Journal of Polymer Analysis and Characterization  3,  177  - 1997

A method for the determination of molecular weight distribution data for polydisperse polymer samples by MALDI-TOF is reported that involves the fractionation of polydisperse samples through analytical GPC columns and collection of fractions. Selected fractions are then analysed by MALDI-TOF and the mass spectra of these nearly uniform samples allow the determination of M-n and M-w averages. The GPC tracing, calibrated against molecular weight values obtained by MALDI, was used to compute molecular weight distribution data of the unfractionated sample. To test the reliability of the molecular weight estimates by the GPC/MALDI-TOF method, a sample of poly(methyl methacrylate) and two samples of poly(dimethyl siloxane), both with wide polydispersity, were analyzed. The results show that the molecular weights of PMMA fractions obtained by MALDI coincide with the GPC calibration plots obtained with anionic PMMA standards, In the case of the two poly(dimethyl siloxanes), two slightly different GPC calibration plots were obtained owing to the different structures of the polymer chains of the two samples. In fact, the MALDI spectra of low MW fractions of these polymers, showed that one sample consists essentially of linear oligomers, whereas the other sample contained cyclic oligomers


479) Effect of methylation of beta-cyclodextrin on the formation of inclusion complexes with aromatic compounds - an ionspray mass spectrometry investigation

P.Cescutti, D.Garozzo, R.Rizzo

Carbohydrate Research  302(1-2),  1  - 1997

The investigation of the inclusion complexes obtained with heptakis-(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-Cdx) or heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin (PM-beta-Cdx) and either 1-anilinonaphthalene-8-sulfonate (ANS) or 2-p-toluidinylnaphthalene-6-sulfonate (TNS) was carried out by means of ionspray mass spectrometry, both in the positive and in the negative ion mode. All the data collected showed that the heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin interacted to a very little extent with TNS and not at all with ANS. On the contrary, heptakis-(2,6-di-O-methyl)-beta-cyclodextrin formed complexes with both aromatic molecules showing a more effective interaction with TNS. Small variations in the number of methoxy substituents in the DM-beta-Cdx molecule did not affect the complexation behaviour significantly. The spectra recorded at different orifice potentials indicated that the complex of heptakis-(2,6-di-O-methyl)-beta-cyclodextrin with TNS is more stable than the one formed with ANS. These results agreed on one hand with the conformations of both the heptakis-(2,6-di-O-methyl)-beta-cyclodextrin and heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin, established by X-ray diffraction studies, and, on the other hand, with the different complexation behaviour of the guest aromatic molecules due to their own geometry. (C) 1997 Elsevier Science Ltd. [References: 17]


480) Discrimination of isomeric oligosaccharides and sequencing of unknowns by post source decay matrix-assisted laser desorption ionization time-of-flight mass spectrometry

D.Garozzo, V.Nasello, E.Spina, L.Sturiale

Rapid Communications in Mass Spectrometry  11(14),  1561  - 1997

The PSD spectra of some isomeric oligosaccharides are investigated in order to study the fragmentation mechanisms. Results show that intense peaks are formed from one or more glycosidic linkage cleavages, while ring fragmentation produces very weak signals. Two analytical applications of post source decay (PSD) to the structural analysis of oligosaccharides are also illustrated: the discrimination of isomeric structures and the identification of a real unknown by combining PSD data with the linkage analysis results.


481) Further Application of a Procedure for Molecular Weight and Molecular Weight Distribution Measurements of Polydisperse Polymers from Their Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectra

D.Vitalini, P.Mineo, E.Scamporrino

Macromolecules  30(18),  5285  - 1997

A recently reported off-line procedure to estimate molecular weight (MW) averages and molecular weight distribution (MWD) index, also for polydisperse polymers, directly from their matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra was applied here to poly(bisphenol A-carbonate) (PC), a poly(ether-sulfone) resin (PES), and poly(dimethylphenylene oxide) (PDMPO), all having a wide polydispersity index. The MW and MWD obtained Values were compared with those determined by GPC or supplied by makers. A structural characterization of these polymers was also performed by examining their MALDI-TOF mass spectra


482) Binding of tripolyphosphate by aliphatic amines: formation, stability, and calculation problems

C.De Stefano, C.Foti, O.Giuffre, P.Mineo, C.Rigano, S.Sammartano

Annali di Chimica  86,  257  - 1996

"The complex formation between tripolyphosphate (P3O105-) and protonated diethylenetriamine (dien), triethylenetetramine (tren), tetraethylenepentamine (tetren) and pentaethylenehexamine (penten), has been studied potentiometrically, in aq. Soln., at 25¦C. It has been found that the species ALHj (A = amine, L = P3O105-) are formed, with j = 1?n (n = 6, 7, 8, and 8 for the above amines, resp.). The stability of these species is quite high [e.g., H3A3 + L5+ = ALH32+: logK = 11.1 (A = tren)] and depends strictly on the charges involved in the formation reaction. The simple linear relationship logK = 1.75 zcation + 0.58 zanion can be used for making a quant. Est. Of the stability of proton-amine-P3O105- complexes. The stability trend is: penten > tetren > trien > dien, and the cationic mixed species are more stable than the anionic ones. The effect of ionic medium and of ionic strength has been carefully taken into account and discussed. Relevant calcn. Problems are met with when dealing with mixed ligand systems: simultaneous formation of several species; strong interferences of Na+ (background salt or NaOH) with polyanions (tripolyphosphate in this work), and of Cl- (HCl) with amines; use of a non const. Ionic medium; a high no. Of mass balance equations. These problems are discussed in detail and a new computer program (STACO, in Quick basic, MS-DOS) is described."


483) Mass spectrometry of synthetic polymers - Mere advances or revolution?

G.Montaudo

Trends in Polymer Science  4,  81  - 1996

"Until recently, polymer scientists have been rather unfamiliar with the advances made in the field of mass spectrometry (MS). However, MS is rapidly becoming indispensable in polymer analysis, and complements in many ways the structural data provided by NMR and IR methods. The MS of polymers is emerging as a revolutionary discipline: it is capable of changing the long-established analytical protocols for the molecular and structural analysis of macromolecules. Some of the most significant applications of modern MS are in: the direct determination of the structure of proteins and biomolecules; the direct determination of the structure and endgroup analysis of polymers; the direct determination of molecular weights and molecular weight distributions; and the direct determination of the sequence distribution and composition of copolymers. The discussion here is mainly limited to the MS of synthetic polymers"


484) Characterization of End Groups in Nylon 6 by MALDI-TOF Mass Spectrometry

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

Journal of Polymer Science part A: Polymer Chemistry  34(3),  439  - 1996

Four samples of Ny6, each terminated by different end groups, i.e., diamino terminated, monoamino terminated (monocapped), dicarboxyl terminated, and amino-carboxyl terminated, were synthesized and analyzed by MALDI-TOF Mass Spectrometry, in order to accurately characterize their structure by direct identification of mass resolved chains. A self-calibrating method for the MALDI-TOF mass spectra of polymeric samples was used in order to distinguish the end groups existing in the four samples of Ny6. The MALDI-TOF spectra showed the presence of protonated, sodiated, and potassiated ions that were assigned to Ny6 chains containing the expecteted end groups. Furthermore, the MALDI-TOF spectra made possible the simultaneous detection of the cyclic oligomers of Ny6 present in these samples, thus achieving the full structural characterization of the molecular species present in these polyamides. © 1996 John Wiley & Sons, Inc. [References: 21]


485) Synthesis and Characterization of POLY(ETHER KETONE) POLY(ETHER SULFONE) Alternating and Sequential Copolymers by Electrophilic Reactions

P.Finocchiaro, G.Montaudo, P.Mertoli, C.Puglisi, F.Samperi

Macromolecular Chemistry and Physics  197(3),  1007  - 1996

The synthesis and NMR characterization of some poly(ether ketone)/poly(ether sulfone) (PEK/PES) alternating copolymers together with a series of sequential homopolymers containing CO, O, S and SO2, bridging groups, all obtained by electrophilic condensation reactions using phosphorus pentoxide/methanesulfonic acid as dehydrating agent, is here reported. Properties of such polymers are compared with those of their model compounds from which it can be inferred that both proton and carbon chemical shifts are very sensitive to the electronic environment generated by the O, S, CO and SO2 bridges. Differential scanning calorimetry indicates that our polymers are essentially amorphous irrespective of the bridging sequence. From viscosity measurements the molecular weights of these copolymers are judged to be very low. [References: 31]


486) Synthesis of AB and ABA Block Copolymers as Compatibilizers in Nylon 6 Polycarbonate Blends

G.Montaudo, C.Puglisi, F.Samperi, F.P.Lamantia

Journal of Polymer Science part A: Polymer Chemistry  34(7),  1283  - 1996

Nylon 6 (Ny6) and Bisphenol A polycarbonate (PC) are immiscible and form biphasic blends. To improve the compatibility of Ny6 and PC several ABA and AB Ny6/PC block copolymers were synthesized, and their compatibilizing behavior on the blends were tested. Block copolymers were prepared by reacting monoamino- or diamino-terminated Ny6 homopolymers with high molecular weight PC at 130 degrees C in anhydrous DMSO. The reaction of diamino- and monoamino-terminated Ny6 with polycarbonate produces block copolymers of the type PC-Ny6-PC (ABA) and PC-Ny6 (AB), respectively, plus a certain amount of unconverted PC degradated to lower molecular weights. To separate the block copolymer from the unconverted PC, a selective fractionation with tetrahydrofuran (THF) and trifluoroethanol (TFE) was carried out. Three different fractions were obtained: THF-soluble fraction, TFE-soluble fraction, and the TFE-insoluble fraction. The scanning electron microscopy (SEM) analysis of a 75/25 (wt/wt) Ny6/PC blend added with 2% of ABA or AB block copolymers, showed the presence of smaller PC particles more adherent to the polyamide matrix, with respect to the same blend nonadded, which is clearly biphasic. The size of the PC particles decreases from ABA to AB compatibilized blends and the adhesion with the matrix is increases in the same way. © 1996 John Wiley & Sons, Inc. [References: 26]


487) Novel Procedure for Molecular Weight Averages Measurement of Polydisperse Plymers Directly from Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectra

G.Montaudo, E.Scamporrino, D.Vitalini, P.Mineo

Rapid Communications in Mass Spectrometry  10(12),  1551  - 1996

"A new method for the determination of reliable molecular weight averages (MW) and polydispersity index (MWD) values for polydisperse polymers, directly analyzing their matrix-assisted laser/desorption ionization time-of-flight (MALDI-TOF) mass spectra, is reported. Our success is due to the concerted effect of an off-line procedure of MALDI-TOF spectrum processing that includes: (i) signal smoothing to improve the recorded traces of the spectra up to high m/z values; (ii) a subtraction of the misleading contribution to the signals introduced by the offset used in spectrum recording; (iii) examination of the spectra up to the highest possible m/z value for a better accuracy in estimating the MW values. To illustrate this method, thre e polymers with a wide polydispersity index, a polydimethylsiloxane, a polymethylmethacrylate, and a bisphenol-A copolyether, have been analyzed. Contrary to the general opinion that MW values can be measured directly by MALDI-TOF only for polymers with a very narrow mass distribution, the data reported here show that our off-line procedure is also able to measure reliable MW values for polydisperse materials. [References: 32]"


488) Thermal Degradation Processes in Poly(xylylene sulfides) Invesyigated by Comparative Direct Pyrolysis MS and Flash Pyrolysis GC/MS Experiments

G.Montaudo, C.Puglisi, J.W.De Leeuw, W.Hartgers, K.Kishore, K.Ganesh

Macromolecules  29(10),  6466  - 1996

The thermal degradation products of two sulfur polymers, poly(styrenedisulfide) (PSD) and poly(styrenetetrasulfide) (PST), were investigated in parallel by direct pyrolysis-mass spectrometry (DPMS) and by flash pyrolysis-GC/MS (Py-GC/MS). The time-scale of the two pyrolysis techniques is quite different, and therefore they were able to detect significantly different products in the pyrolysis of PSD and PST because of the thermal lability of sulfur-containing compounds. However, the results obtained are not contradictory, and satisfactory mechanisms for the thermal degradation of PSD and PST have been derived from the overall evidence available. Pyrolysis compounds containing sulfur, styrene, and a number of cyclic styrene sulfides and diphenyldithianes have been observed by DPMS. However, in flash pyrolysis-GC/MS, styrene, sulfur, only one cyclic styrene sulfide, and two isomers of diphenylthiophene have been detected. These thiophene derivatives were indeed absent among the compounds obtained by DPMS because they were the terminal (most thermally stable) species arising from further decomposition of the cyclic styrene sulfides formed in the primary thermal degradation processes of PSD and PST. [References: 27]


489) Evidence for ester exchange reactions and cyclic oligomers formation in the ring opening polymerization of lactide with Aluminium complex initiators

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi, N.Spassky, A.LeBorgne, M.Wisniewski

Macromolecules  29(10),  6461  - 1996

Four polylactide samples, obtained by ring-opening polymerization with an aluminum alkoxide initiator derived from a Schiffs base, were characterized by MALDI-TOF mass spectrometry. The MALDI mass spectra of these polylactides show well-resolved signals that can be reliably assigned to polylactide oligomers. Remarkably, both even-membered and odd-membered oligomers are present in these MALDI spectra. The presence of odd-membered oligomers cannot be explained on the basis of the lactide ring-opening polymerization, and one must admit that ester-exchange reactions do occur parallel to the polymerization process, causing a random cleavage of the polylactide chain. Furthermore, evidence for the presence of cyclic lactides was found in the MALDI-TOF spectrum of a low molecular weight polylactide fraction, indicating that ester exchange occurs also in polylactides by intramolecular end-biting reactions (ring-chain equilibration), with formation of cyclic oligomers. [References: 31]


490) End groups characterization of Poly(methylphenylsilane) by alkali metal salts doped MALDI-TOF mass spectra

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi, M.Sepulchre

Macromolecular Chemistry and Physics  197(9),  2615  - 1996

The end groups of a sample of poly(methylphenylsilane) (PMPS) obtained by the Wurtz coupling reaction of diorganodichlorosilane were characterized by MALDI-TOF mass spectrometry. Three fractions were obtained by fractionation of a PMPS sample with methanol, in order to get information on the distribution of end groups as a function of the molecular weight. The MALDI mass spectra of these fractions showed well-resolved signals up to 2500 Da corresponding to open chain oligomers of PMPS bearing four different types of end groups: -Si-(CH3)(3), -O-Si-(CH3)(3), -O-CH3, -H. Six different types of linear oligomers were identified together with a sizeable amount of cyclic oligomers, most likely generated during the polymerization step. The problem of isobar mass series in the MALDI spectra due to clusters of oligomers with Li+, Na+, K+ was solved by comparing the MALDI spectra of PMPS fractions with and without the addition of a specific alkaline salt (KCl or NaI) to the solution containing the sample and matrix. The intensity of the oligomer clusters with the specific cation were enhanced with respect to the others. The mass shifts observed in the MALDI-TOF doped spectra with respect to the undoped ones allowed the unambiguous assignments of the isobar peaks corresponding to PMPS oligomers. [References: 22]


491) Anionic Polymerization of Pentadecanolide. A New Route to Potentially Biodegradable Aliphatic Polyesters

M.Juzwa, M.Kowalczuk, Z.Jedlinski, M.S.Montaudo

Macromolecular Chemistry and Physics  197(9),  2923  - 1996

The anionic polymerization of pentadecanolide (1-oxa-2-cyclohexadecanone) initiated with potassium alkoxides was investigated. Polymerization proceeds under mild conditions (tetrahydrofuran, 35 degrees C) to form high-molecular-weight polymer (number-average molecular weight (M) over bar(n) up to 100000). The formation of cyclic oligomers, via back-biting reaction, was demonstrated by means of gel-permeation chromatography (GPC) and matrix assisted laser desorption ionisation-time of flight (MALDI-TOF) analyses


492) Study of the inclusion complexes of aromatic molecules with cyclodextrins usin ionspray mass spectrometry

P.Cescutti, D.Garozzo, R.Rizzo

Carbohydrate Research  290(2),  105  - 1996

"The formation of inclusion complexes between cyclodextrins (cyclohexa-, cyclohepta-, and cyclooctamylose) and either 1-anilinonaphthalene-8-sulfonate or 2-p-toluidinylnaphthalene-6-sulfonate was investigated by ionspray mass spectrometry operated both in the positive and in the negative ion mode. This soft ionisation technique allowed the detection of the inclusion complexes; the presence of false positives was excluded by increasing the voltage at the orifice which caused breakage of the electrostatic adducts and some fragmentation of the free cyclodextrin molecules, but left the inclusion complexes intact. The spectra recorded in the negative mode showed the presence of complexes formed by two cyclodextrin molecules and one aromatic molecule; such stoichiometry was not detected in the positive mode.


493) Synthesis and MALDI-TOF MS Characterization of High Molecular Weight Poly(1,2-dihydroxybenzenephthalates) Obtained by Uncatalyzed Bulk Polymerization of O,OÆ-phthalid-3-ylidene catechol or 4-Methyl-O,O'-phthalyd-3-ylidenecatechol

E.Scamporrino, D.Vitalini, P.Mineo

Macromolecules  29(17),  5520  - 1996

A new procedure to obtain high molecular weight poly(1,2-dihydroxybenzene phthalates) by bulk polymerization of some spiro-compounds is described. O,O'-Phthalid-3-ylidenecatechol (I) and 4-methyl-O,O'-phthalid-3-ylidenecatechol (II) spiro-compounds have been synthesized and used as monomers. Poly(1,2-dihydroxybenzene phthalate) (III) and poly(1,2-dihydroxy-4-methylbenzene phthalate) (IV) have been prepared by heating at 200 degrees C of spiro-compounds I and II, respectively, without addition of catalyst. The resulting polyesters III and TV have been characterized by GPC, TG, DSC, NMR, FAB-MS, and MALDI-TOF MS analyses. The GPC curves of the obtained materials showed that high molecular weight polyesters, containing only a very little amount of low molecular weight oligomers, have been formed. The structural characterization of these polyesters by FAB and MALDI-TOF mass spectrometric analyses showed that they are constituted exclusively of open-chain macromolecules having both hydroxy end-groups. Data collected suggest that in the bulk polymerization of spiro-compounds I and II a possible chain growth mechanism of polymerization is active, which is strongly inhibited by acid species


494) Synthesis and MALDI-TOF Characterization of an Exatly Alternating Copolycarbonate and Two Random Copolyethers Containing Schiff Base Cu (II) Complex Nonlinear Optical (NLO) Units in the Main Chain

D.Vitalini, P.Mineo, S.Di Bella, I.Fragalà, P.Maravigna, E.Scamporrino

Macromolecules  29(13),  4478  - 1996

Copolymers containing second-order nonlinear optical (NLO) active transition metal complexes into the main chain were synthesized and characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), TG, and DSC analyses for the first time. The Cu(II) complex Ia of the N,N'-bis(2,4-dihydroxybenzylidene)-1,2-phenylenediamine ligand was synthesized and used as the NLO unit. The polycondensation between the copper(II) complex Ia (NLO unit) and butanediol bischloroformate was performed to obtain the exactly alternating copolycarbonate II. Two copolyethers, III ana IV, containing different amounts of NLO units in the main chain (10% and 47%, respectively), were obtained by reaction of dibromomethane and suitable mixtures of the Cu(II) diimine complex Ia and bisphenol A in different molar ratios. The resulting copolymers II-IV were characterized by MALDI-TOF MS. The structure of low molecular weight oligomers contained in each polymeric sample inferred by MALDI spectra was found diagnostic of their composition and microstructure. Copolymers II-TV exhibit very good thermal stability and are promising candidates for second-order NLO materials


495) HPLC analysis of cyclic adenosine diphosphate ribose and adenosine diphosphate ribose: determination of NAD+ metabolites in hippocampal membranes

G.Casabona, L.Sturiale, M.R.L

The Italian Journal of Biochemistry  44(5),  258  - 1995

Cyclic ADP-ribose (cADPR) and ADPR were sepd. by high-performance liq. chromatog. (HPLC) on a CarboPac PA-1 column at strong basic pH and quantitated by a pulsed amperometric detector. Although this HPLC method was quite sensitive and highly reproducible, it did not allow the sepn. of cADPR from guanosine monophosphate (GMP) which, when present, could be removed by ion-affinity chromatog., using gel-immobilized Fe3+-columns. Crude synaptic membranes from rat hippocampi were incubated with NAD and acidic exts. were subjected to HPLC anal. after neutralization. Incubation led to a time-dependent formation of ADPR, which was amplified when membranes were incubated in the presence of guanosine trisphosphate (GTP), guanosine-5'-O-(3-thiotrisphosphate) (GTP-g-S) or AlF3. The cADPR did not accumulate in detectable amts. and only a minimal proportion (


496) Selective Formation of Cyclic Monomer, Dimer, Or Trimer in the Pyrolysis of Isomeric Dihydroxybenzene Phthalate Polyesters (1994)

D.Vitalini, E.Scamporrino, P.Maravigna

Macromolecules  27(8),  2291  - 1995



497) Polymers in Pisa - Pat-95, 3Rd International-Symposium on Polymers for Advanced Technologies, Pisa, Italy, 11-15 June 1995

G.Montaudo

Trends in Polymer Science  3,  416  - 1995



498) Degradation Behaviour of Poly(methyl methacrylate-g-3-hydroxybutyrate)Polymer Films

Z.Jedlinski, G.Adamus, M.Kowalczuk, A.Ballistreri, T.Scherer, R.W.Lenz

Polymer Degradation and Stability  50(3),  269  - 1995

Poly(methyl methacrylate-g-3-hydroxybutyrate) films were prepared from new graft polymers synthesised by an anionic grafting reaction of 3-butyrolactone (3-BL) on poly(methyl methacrylate) (PMMA). The resulting graft polymers form a transparent film of a one phase system, as revealed by DSC measurements. A plasticisation effect was observed for film samples containing the PBL grafted chains. This effect increased with increasing amount of PBL in the graft copolymer. The mechanical properties of the films were investigated, and thermal, hydrolytic and enzymatic degradation behaviours were evaluated. Disintegration of the films was observed during their hydrolytic degradation in phosphate buffer.


499) Eleven newly characterized xyloglucan oligoglycosyl alditols:the specific effects of sidechain structure and location on 1 H NM chemical shifts

W.S.York, G.Impallomeni, M.Hisamatsu, P.Albersheim, A.G.Darvill

Carbohydrate Research  267(1),  79  - 1995

Eleven previously uncharacterized oligosaccharides, each containing from seventeen to twenty glycosyl residues, were isolated from the xyloglucan produced by suspension-cultured Acer pseudoplatanus cells and characterized by H-1 NMR spectroscopy, fast-atom bombardment mass spectrometry, and matrix-assisted laser-desorption mass spectrometry. The complex mixture of xyloglucan oligosaccharides released by endo-(1-->4)-beta-glucanase (Trichoderma reesei) treatment of cell walls was similar to that released by digestion of the soluble xyloglucan present in the culture medium. The oligosaccharides were converted to oligoglycosyl alditols by borohydride reduction and purified by a combination of gel-permeation (Bio-Gel P-2) chromatography, normal-phase HPLC, reversed-phase HPLC, and high-performance anion-exchange (HPAE) chromatography. Eleven new oligoglycosyl alditols (along with several others that had been previously characterized) were isolated and characterized, allowing additional correlations between xyloglucan structure and specific chemical shift effects in the H-1 NMR spectra to be determined. The correlations between structural and spectral features deduced in this study will facilitate the structural determination of a wide range of xyloglucans and their subunit oligosaccharides


500) Metabolism of xyloglucan generates xylose-deficient oligosaccharide subunits of this polysaccharide in etiolated peas

R.Guillen, W.S.York, M.Pauly, J.An, G.Impallomeni, P.Albersheim, A.G.Darvill

Carbohydrate Research  277(2),  291  - 1995

Oligosaccharide subunits of xyloglucan were isolated from the stems and roots of etiolated pea plants and structurally characterized. The two most abundant subunits of pea xyloglucan are the well-known nonasaccharide, XXFG, and heptasaccharide, XXXG. In addition, significant amounts of oligosaccharides that have not previously been reported to be subunits of pea xyloglucan were detected, including a decasaccharide, XLFG, two octasaccharides, XLXG and XXLG, a pentasaccharide, XXG, and a trisaccharide, XG. Several novel oligosaccharide subunits, including the octasaccharide, GXFG, and the hexasaccharide, GXXG, were also found. Xyloglucan oligosaccharides generated by treatment of intact pea stem cell wails were compared to oligosaccharides generated by endoglucanase treatment of xyloglucan polysaccharides obtained by subsequent alkali extraction of the same cell walls. The results suggest that the xyloglucan in etiolated pea stems is distributed between at least two domains, one of which is distinguished by its enzyme accessibility. We further hypothesize that the chemical modification of a xyloglucan during cell-wall maturation depends on its physical environment (i.e., the domain in which it resides). For example, only the endoglucanase-released material, representing the enzyme-accessible xyloglucan domain, contains significant amounts of the two unusual oligosaccharide subunits, GXXG and GXFG, both of which have a nonreducing terminal glucosyl residue. This structure may be generated during cell-wall maturation by the sequential action of an endolytic enzyme (such as xyloglucan endotransglycosylase or endoglucanase) and an alpha-xylosidase


501) Matrix Assisted Laser Desorption/Ionization Mass Spectrometry of Polysaccharides

D.Garozzo, G.Impallomeni, E.Spina, L.Sturiale, F.Zanetti

Rapid Communications in Mass Spectrometry  9(10),  937  - 1995

In this paper we report matrix-assisted laser desorption/ionization (MALDI) mass spectra of dextrans up to 100 000 Da molecular weight and compare these measurements with those obtained by conventional size-exclusion chromatography with low-angle laser light scattering (SEC/LALLS). These results extend the usefulness of MALDI-MS to higher molecular weight polysaccharides and give some insights into the MALDI process


502) Identification of N-acetylglucosamine and 4-O(1carboxyethyl)mannose in the exopolysaccharide from Cyanospyra capsulata

D.Garozzo, G.Impallomeni, E.Spina, L.Sturiale, A.Cesaro, P.Cescutti

Carbohydrate Research  270(1),  97  - 1995



503) Structural Characterization of Oligomers Formed in the Reaction between Phthaloyl Dichloride and Catechol, 4-Methylcatechol or Ditiocatechol

F.Mancino, E.Scamporrino, D.Vitalini

Macromolecules  28,  5419  - 1995

LC and HPLC chromatographic experiments were made to separate the low molecular weight oligomers contained in three totally aromatic polyesters obtained by the condensation reaction between phthaloyl dichloride and catechol, 4-methylcatechol, or dithiocatechol. The characterization of the extracted oligomers was performed by techniques of thermal analysis, i.e. differential scanning calorimetry (DSC) and thermogravimetry (TG), and techniques of structural identification, i.e. nuclear magnetic resonance (NMR), direct pyrolysis mass spectrometry (DP-MS), fast-atom bombardment mass spectrometry (FAB-MS), and X-ray diffraction analysis. Mass spectrometric data show that the lower molecular weight product contained in each of the three polymeric materials has the following composition: C14H8O4 (mw = 240), C15H10O4 (mw = 254) or C14H8O2S2 (mw = 272). All the data collected in this work, and in particular those obtained by NMR and X-ray diffraction analyses, show that these products have a spiro structure, whereas the other extracted products with higher molecular weight are, as expected, cyclic and linear oligomers having ester linkages


504) A Method for the Interpretation of Pyrolysis Mass Spectra of Polyesters

G.Montaudo, C.G.Georgakopoulos, M.Sthatheropulos, G.Parissakis

Journal of Analytical and Applied Pyrolysis  34,  127  - 1995

"A new method for the interpretation of pyrolysis-mass spectra of polyesters is described. The method is based on the use of table of pyrolysis-mass spectral data of polyesters. It has two steps: first, the examination of the unknown pyrolysis-mass spectrum in order to extract information about the relationship of specific ion masses with particular polyester structures; second the recongnition and the identification of mass series in the spectrum. Tables of pyrolysis-mass spectrometry (Py-MS) data of polyesters are presented. Examples of the application of the interpretation method are given. The advantages in limitations of the method are presented and discussed. [References: 36]"


505) Sequence Distribution of PES/PEK Copolymers by MS and by 13C-NMR.

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

Macromolecular Chemistry and Physics  196(2),  499  - 1995

The sequence distributions of four poly(ether-sulfone)/poly(ether-ketone) (PES/PEK) copolymer samples were determined by means of fast atom bombardment mass spectrometry (FAR-MS) and by C-13 NMR spectroscopy. The controlled partial degradation of the copolymer chains to produce oligomers suitable of FAB-MS analysis was performed with sodium methoxide in dimethyl sulfoxide solution at 130 degrees C, and the experimental conditions were optimized. The sequential arrangements of ether-sulfone/ether-ketone units present in these materials were estimated by a best-fit minimization method using the MACO4 computer program which compares the experimental FAB-MS spectral intensities with theoretical intensities. Random PES/PEK copolymer samples showed quite the same sequence arrangements as expected from monomer feed-ratios used in the syntheses. Instead, a PES/PEK copolymer sample expected to be exactly alternating (from the synthesis procedure) showed 44% of random sequences owing to the transetherification reaction which occurred in the synthesis. The results of sequential analysis obtained from C-13 NMR data compare well with the data obtained by the FAB-MS analysis. [References: 29]


506) Synthesis and Characterization of Polyesters Produced by Rhodospirillum Rubrum from Pentenoic Acid

A.Ballistreri, G.Montaudo, G.Impallomeni, R.W.Lenz, A.W.Ulmer, C.Fuller

Macromolecules  28,  3664  - 1995

Two different terpolyesters were obtained by fermentation of Rhodospirillum rubrum fed either with 4-pentenoic acid alone or with an equimolar mixture of 4-pentenoic and valeric acids. Sequence distributions of these two polyesters were determined by fast atom bombardment mass spectrometry (FAB-MS) of the oligomers prepared by partial methanolysis and separated by HPLC. The distributions in both polymers follow Bernoullian statistics, indicating that both are random terpolyesters. [References: 19]


507) Characterization of Polymers by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry-End Group Determination and Molecular Weight Estimates in Poly(ethylene glycols)

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

Macromolecules  28,  4562  - 1995

"Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) allows mass measurements of large molecules such as those present in synthetic and natural macromolecules. We have used a self-calibrating method for the MALDI-TOF spectra of polymers, enabling us to obtain: accurate mass values. Poly(ethylene glycol) (PEG) samples having two different kinds of end groups were used in our work: (i) anionic PEG, H-(CH2-CH2-O)(n)-H; (ii) cationic PEG, H-(CH2-CH2-O)(n)-OH. The MALDI-TOF spectra recorded in reflected mode allowed unambiguous identification of the end groups present in these PEG samples. Five anionic PEG samples with very narrow molecular weight distributions (MWD) were studied. The MALDI-TOF spectra of PEGs were recorded in both linear and reflected modes. Due to the high sensitivity and the highly linear response of HIMAS (a microchannel detector equipped with a photomultiplier), measurements of MALDI-TOF spectra were used in our work. To estimate the MW and MWD of the PEG samples. Our results show that the molecular weight estimates provided by MALDI-TOF measurements agree with the values obtained by conventional techniques such as GPC, osmometry, and viscometry. [References: 23]"


508) Characterization of Polymers by Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry: Molecular Weight Estimates in Samples of Varying Polydispersity

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

Rapid Communications in Mass Spectrometry  9(5),  453  - 1995

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows the detection of large molecules such as those present in synthetic and natural macromolecules. Synthetic polymers may show a wide range of molecular weight distributions (MWD), according to the synthetic method used in their preparation. We have studied several poly(methylmethacrylate) (PMMA), poly(styrene) (PS) and poly(ethyleneglycol) (PEG) samples with varying MWD, and also a number of condensation polymers such as Nylon-6, poly(carbonate) and poly(ester). Measurements of MALDI-TOF spectra in the linear mode were used in our work to estimate the molecular weight (MW) and MWD of the polymer samples. Our results show that the molecular weight estimates provided by MALDI-TOF measurements agree with the values obtained by conventional techniques, such as gel-permeation chromatography (GPC), only in the case of polymer samples with very narrow molecular weight distribution. However, when the polydispersity reaches values around 1.10 the difference between the MW measured by GPC and measured by MALDI may amount to up to about 20%. At higher dispersions, the MALDI spectra fail to yield reliable MW values. [References: 29]


509) Molecular Weight Distribution of Poly(dimethylsiloxane) by Combining Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry with Gel-permeation Chromatography Fractionation

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

Rapid Communications in Mass Spectrometry  9(12),  1158  - 1995

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows detection of large molecules such as those present in synthetic and natural macromolecules. Until recently, it was reported that MALDI-TOF measurements can provide correct molecular weight (MW) estimates only for nearly monodisperse polymer samples. We have now developed a methodology for polydisperse samples. We recorded the gel-permeation chromatography (GPC) trace of a polydisperse polymeric sample of poly(dimethylsiloxane) (PDMS), collecting 42 fractions. Selected fractions were analyzed by MALDI-TOF and the average MW of each fraction was determined, allowing a calibration of GPC curves against absolute MW. The calibrated GPC trace was then used to compute average MW and molecular-weight distribution (MWD) of the unfractionated poly(dimethylsiloxane) sample. In the spectra of low molecular-weight fractions, the resolution is high enough to resolve the contributions of the various PDMS oligomers as separate signals. [References: 26]


510) Separation and Structural Characterization of Cyclic and Open Chain Oligomers Produced in the Partial Pyrolysis of Microbial Poly(Hydroxbutyrates)

R.Abate, A.Ballistreri, G.Montaudo, M.Giuffrida, G.Impallomeni

Macromolecules  28,  7911  - 1995

"To explore the possibility of using the partial pyrolysis of microbial poly(hydroxybutyrates) (PHBs) for obtaining single 3HB, 4HB, and mixed 3HB/4HB oligomers, the pyrolysis of P(3HB), P(4HB), and P(3HB-co-4KB) was performed and the products obtained were analyzed by HPLC and fast atom bombardment mass spectrometry (FAB-MS). Our results show that the partial pyrolysis of P(3HB) and P(4HB), followed by HPLC separation of the products, affords a suitable route for the synthesis of linear 3HB oligomers and of 4HB oligolides, respectively. The thermal degradation of P(3HB), P(4HB), and P(3HB-co-4HB) copolymers containing 3-34% of 3HB units was investigated by using several techniques: monitoring the time-dependent changes in molecular weight of melt samples in the range 180-200 degrees C; direct pyrolysis mass spectrometry; preparative pyrolysis and subsequent IR, NMR, HPLC, and FAB-MS analysis of the pyrolysate. Contrary to the claim that the rate constant (K-d) Of chain scission is not influenced by the composition of the copolyesters, our results show that the rate of chain scission is influenced by the composition of copolyesters and that a mixture of cyclic and open chain oligomers is formed in the pyrolysis process. These findings indicate that P(3HB-co-4HB) copolymers undergo thermal degradation by two competitive random chain scission mechanisms: a beta-CH hydrogen transfer at the 3HB units and an ester exchange cyclization at the 4HB units. [References: 22]"


511) Molecular and Structural Characterization of Polydisperse Polymers and Copolymers by Combining Maldi-Tof Mass Spectrometry with GPC Fractionation

G.Montaudo, D.Garozzo, M.S.Montaudo, C.Puglisi, F.Samperi

Macromolecules  28,  7983  - 1995

Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) allows detection of large molecules such as those present in synthetic and natural macromolecules. Until recently, it was reported that MALDI-TOF measurements can provide correct molecular weight (MW) averages only for samples with a narrow MW distribution (M(w)/M(n) less than or equal to 1.20). We have now developed a methodology for polydisperse samples. We recorded the GPC trace of two polydisperse polymeric samples, namely, poly(butylene adipate) (PEA) and poly(butylene adipate-co-butylene succinate) (PBAS), collecting about 40-50 fractions per run. Selected fractions were analyzed by MALDI-TOF, and the average MW of each fraction was determined, allowing calibration of the GPC curves against absolute MW. The two calibrated GPC traces were then used to compute average MW and molecular weight distributions (MWD) of the unfractionated samples. End group analysis from MALDI-TOF spectra revealed that the PEA sample is composed of seven different types of chains. For the copolymer sample, PBAS, analysis of the MALDI spectra established a random sequence distribution of comonomer units. The succinate/adipate molar ratio calculated from the MALDI spectra is in good agreement with the molar ratio found by NMR. [References: 25]


512) Sequence of Polymers by Mass Spectrometry

G.Montaudo

Macromolecular Symposia  98,  899  - 1995

Mass Spectrometry, being able to look at the mass of individual molecules in a mixture of homologues, is particularly suitable for the detection of a series of oligomers. However, mass spectra had not been exploited to estimate oligomers distributions, due to the diffuse notion that a lack of correlation existed between peak intensities and concentration of the oligomers in the mixture. The introduction of soft-ionization techniques has largely eliminated this problem. A novel method for the determination of the microstructure of copolymers is presented here. We have recently found that opportune decoding of the information contained in the mass spectral intensities Leads to the determination of composition and microstructure in copolymers, and this represents a significant progress. Statistical modeling of the mass spectral intensities of copolymers has been used to derive information on the distribution of monomers along the copolymer chain, and an automated procedure to find the composition and the sequence of the copolymers analyzed has been developed. The statistical analysis of copolymers makes use of Bernoullian and Markovian models in order to characterize the microstructure of copolymer samples, and assuming a theoretical distribution and then fitting the calculated oligomer abundances with the experimental MS peak intensities, the copolymer composition can be determined. A method is also reported to obtain the copolymer conposition by direct analysis of the mass spectra. These theories have been applied to determine the composition and the microstructure of several copolymers whose mass spectra have been reported in the most recent literature. [References: 31]


513) Enthalpimetric measurements in solid-solid interactions: The reaction of dicarboxylic acids with amino acids. Part 1

G.Siracusa, L.Abate, P.Mineo

Thermochimica Acta  232(1),  117  - 1994

The ability of dicarboxylic acids to interact with amino acids to form monomeric or polymeric products has been obsd. by means of DSC and TG techniques.The solid-solid reactions have been carried out, the assocd. DH values evaluated, and the reaction mechanism elucidated. In the solid state phthalic acid interacts with amino acid to form the monomeric product N-phthaloyl amino acid, by losing two water mols. The product formed has been characterized from its IR and NMR spectra.


514) Selective Formation of Cyclic Monomer, Dimer or Trimer in the Pyrolysis of Isomeric Dihydroxybenzene Phthalate

D.Vitalini, E.Scamporrino, P.Maravigna

Macromolecules  27(8),  2291  - 1994

The thermal degradation processes occurring in the pyrolysis of the isomeric aromatic polyesters I-III synthesized by condensation reaction between phthaloyl chloride and catechol, resorcinol, or hydroquinone, respectively, were investigated. Data obtained by direct pyrolysis mass spectrometry (DP-MS) indicate that the thermal decomposition processes of these polymers yield only and selectively cyclic 1,2-dihydroxybenzene phthalate, bis(1,3-dihydroxybenzene phthalate), and tris(1,4-dihydroxybenzene phthalate) as a function of the polymeric structure. These results were also confirmed by GPC and MS analyses of the pyrolytic materials collected during the thermal degradation experiments under vacuum of polymers I-III. As a consequence, it is possible to identify each of the three isomeric polymers just on the basis of their DP-MS spectra


515) Exchange Reactions Occurring through Active Chain Ends. Melt Mixing of Nylon 6 and Polycarbonate

G.Montaudo, C.Puglisi, F.Samperi

Journal of Polymer Science part A: Polymer Chemistry  32,  15  - 1994

The chemical reactions occurring in the melt mixing of nylon6/polycarbonate (Ny6/PC) at 240-degrees-C were investigated. The reaction of equimolar Ny6/PC blends can be reconciled within the overall scheme of an exchange reaction occurring with the attack of active amino terminals on the inner carbonate groups. We have performed the synthesis of low molecular weight amino-terminated nylon 6 and the effect of the active amino terminal groups on the exchange kinetics was investigated. The exchange reaction yields sizeable amounts of copolymer, in fact after 75 min of melt mixing the (initially equimolar) blend contains 30 mol of unreacted PC and 70 mol of Ny6/PC copolymer (all the Ny6 was therefore incorporated in the copolymer). Trifluoroacetylation of nylon 6 was used to produce CHCl3-soluble Ny6/PC copolymers, that could be analyzed by NMR. The NMR analysis yielded, beside the copolymer composition, evidence of the presence of urethane units interconnecting the Ny6 and PC blocks. The amount of urethane units increased with the reaction time, indicating a reduction of the block size as a function of the extent of exchange. Our study established the structure of the products formed, provided the materials balance of the process, and investigated some salient kinetic aspects. A thermal degradation study was also performed by thermogravimetry and direct pyrolysis mass spectrometry, to identify the products formed in the thermal treatment of the blends and to investigate the possible role of the inner amide groups in the intermolecular exchange reactions occurring between Ny6 and PC. Our results prove that these reactions occur above 300-degrees-C, and that only the cleavage of carbonate groups, by means of Ny6 amino end groups, is actually occurring at 240-degrees-C. © 1994 John Wiley & Sons Inc. [References: 31]


516) Primary Thermal Degradation Processes of PES and PPO Investigated by Direct Pyrolysis Mass-Spectrometry

G.Montaudo, C.Puglisi, R.Rapisardi, F.Samperi

Macromolecular Chemistry and Physics  195,  1225  - 1994

The thermal degradation processes which occur in poly(ether-sulfone) (PES) and poly(phenylene oxide) (PPO) have been studied by Direct Pyrolysis-Mass Spectrometry (DPMS). The pyrolysis mass spectra of PES and PPO contain molecular ions up to m/z 700, corresponding to pyrolysis compounds of sufficient size to allow the characterization of the primary processes which occur in the thermal cleavage of these polymers. The results obtained indicate that the thermal degradation of PES and PPO proceeds by thermal cleavage of the groups located at the bridges. In the case of PPO the bridges are all homogeneous, and therefore both an intramolecular thermal rearrangement or a radical cleavage process can account for the formation of the primary pyrolysis products. Formation of dibenzofuran units along the PPO chain is a parallel thermal process. In the case PES the simultaneous thermal cleavage of two different bridged units, diphenyl sulfone and diphenyl ether, occurs. Extrusion of SO2, with consequent formation of compounds containing biphenyl units, is observed in the thermal degradation of PES. This process is accompanied by formation of dibenzofuran units along the polymer chain, as expected from the thermal cleavage of diphenyl ether units, and by another rearrangement of the polymer backbone, yielding structures containing more oxygen atoms with respect to that of PES. [References:23]


517) Primary Thermal Degradation Processes of PEK and PEK/PES Copolymers Investigated by Direct Pyrolysis Mass-Spectrometry

G.Montaudo, C.Puglisi, F.Samperi

Macromolecular Chemistry and Physics  195,  1241  - 1994

The mechanisms of thermal degradation of poly(ether-ketone) (PEK) and four poly(ether-ketone)/poly(ether-sulfone) copolymers (PEK/PES) have been investigated by direct pyrolysis-mass spectrometry (DPMS). Several families of pyrolysis compounds with H, OH and CHO end-groups have been identified in the pyrolysis mass spectra of PEK. All these pyrolysis compounds can arise from degradation mechanisms involving cleavages of the bridged groups (diphenyl ether and dibenzophenone units). Our data show that the main degradation products of PEK are aldehydes, most likely formed by an intramolecular thermal cleavage of benzophenone units. Compounds containing dibenzofuran units have also been observed in the DCI mass spectrum of PEK. The thermal decomposition of a low molecular weight PEK sample occurs in two stages with the maxima of decomposition at 390-degrees-C and 490-degrees-C, respectively. This fact indicates the occurrence of an end-group initiated thermal decomposition in the early degradation stage which is not present in the case of the high molecular weight PEK sample. The pyrolysis of PEK does not produce compounds containing biphenyl units, indicating that extrusion of carbonyls or recominbation processes are not involved. The thermal degradation compounds of the PEK/PES copolymers originate from the thermal cleavage of the bridge groups (diphenyl ether, benzophenone and diphenyl sulfone). The pyrolysis mass spectra of 1 : 1 (alt.), 1 : 1 (random), 3 : 1 and 1 : 3 PEK/PES copolymers appear essentially identical (apart for obvious differences in peak intensities), indicating that the molecular rearrangements (SO2 extrusion, transesterification, cleavage of bridges) which occur at higher temperatures and/or in the pyrolysis processes are able to randomize the distribution of comonomer units originally present in the copolymers. Differences in peak intensities have been found to reflect almost quantitatively the molar composition of the copolymers. [References: 16]


518) Thermal Degradation of Microbial Poly(4-Hydroxybutyrate)

R.Abate, A.Ballistreri, G.Impallomeni, G.Montaudo

Macromolecules  27(2),  332  - 1994

We obtained by microbial synthesis an almost pure poly(4-hydroxybutyrate) (P(4HB)) sample (i.e., a P(3HB-co-4HB) copolymer containing only 3% of 3HB units). The thermal degradation of this material was investigated using thermogravimetry, direct pyrolysis mass spectrometry and also by preparative pyrolysis and subsequent NMR analysis of the pyrolyzate. Previous studies(7) on P(3HB-co-4HB) copolyesters have reported that the thermal degradation process occurs by a beta-CH hydrogen transfer, similar to the well-known case of P(3HB). However, the latter work did not distinguish between the thermal degradation fate of 3HB and 4HB units. Our findings indicate that the thermal decomposition of P(4HB) yields a series of cyclic oligomers (i.e., gamma-butyrolactone and its higher homologs) by an intramolecular exchange mechanism. Detailed mass spectrometric and H-1-NMR evidence is presented to prove this point. [References: 17]


519) Primary Thermal Degradation Processes Occurring in Polyphenylenesulfide Investigated by Direct Pyrolysis Mass-Spectrometry

G.Montaudo, C.Puglisi, F.Samperi

Journal of Polymer Science part A: Polymer Chemistry  32,  1807  - 1994

"The thermal degradation processes which occur in poly(phenylenesulfide) (PPS) have been studied by direct pyrolysis-mass spectrometry (DPMS). The structure of the compounds evolved in the overall temperature range of PPS decomposition (400-700-degrees-C) suggests the occurrence of several thermal decomposition steps. At the onset of the thermal degradation (430-450-degrees-C) this polymer decomposes with the formation of cyclic oligomers, generated by a simple cylization mechanism either initiated at the - SH end groups or by the exchange between the inner sulfur atoms along the polymer chain. At higher temperature (>500-degrees-C) another decomposition reaction takes over with the formation of aromatic linear thiols. The formation of thiodibenzofuran units by a subsequent dehydrogenation reaction occurs in the temperature range of 550-650-degrees-C; in fact, pyrolysis products with a quasi-ladder structure have also been detected. Ultimately, above 600-degrees-C, extrusion of sulfur from the pyrolysis residue occurs with the maximum evolution at the end of decomposition (about 700-degrees-C). It appears, therefore, that the residue obtained at high temperature tends to have a crosslinked, graphite-like structure from which the bonded sulfur is extruded. © 1994 John Wiley & Sons, Inc. [References: 18]"


520) Synthesis and NMR Characterization of a Series of Linear Monodisperse Poly(Aryl Ether Ketone) and Poly(Aryl Ether Sulfone) Oligomers

P.Finocchiaro, G.Montaudo, P.Mertoli, F.Samperi

Macromolecular Chemistry and Physics  195(8),  2779  - 1994

New poly(aryl ether ketone) and poly(aryl ether sulfone) monodisperse model oligomers were synthesized in good yield via nucleophilic reactions. They were characterized by means of H-1 and C-13 NMR spectroscopy, and all chemical shifts were assigned to the corresponding nuclei. Both proton and carbon chemical shifts are very sensitive to the electronic environment generated by the O, CO and SO2 bridges, but in all oligomers, nuclei with similar electronic environments are very close to each other no matter what the sequence or the length of the oligomer is. Only quaternary carbons are more sensitive to the nature of the bridging groups, and therefore their chemical shifts can be of utility in sequencing the polymers. [References: 16]


521) Poly(Arylenecarbonate)s Oligomers by Carbonate Interchange Reaction of Dimethyl Carbonate with Bisphenol-A - FAB-MS Evidence for the Nature of End Groups in the Oligomers

A.G.Shaikh, S.Sivaram, C.Puglisi, F.Samperi, G.Montaudo

Polymer Bulletin  32(4),  427  - 1994

Fast atom bombardment mass spectrometry (FAB-MS) has been used to identify oligomers with different end groups obtained by the carbonate interchange reaction of bisphenol-A with dimethyl carbonate and the partial methanolysis of poly(bisphenol-A carbonate)s. Based on the FAB-MS data, a reaction pathway for the formation of compounds in the synthesized oligomers is proposed.


522) Thermal Degradation Products of Poly(Styrenesulfides) Investigated by Direct-Pyrolysis MS and Flash-Pyrolysis-GC/MS

G.Montaudo, G.Puglisi, M.Blazsò, K.Kishore, K.Ganesh

Journal of Analytical and Applied Pyrolysis  29,  207  - 1994

The thermal degradation products of two sulfur polymers, poly(styrenedisulfide) (PSD) and poly(styrenetetrasulfide) (PST), were investigated in parallel by direct pyrolysis-mass spectrometry (DPMS) and by flash pyrolysis-GC/MS (Py-GC/MS). The time-scale of the two pyrolysis techniques is quite different, and therefore they were able to detect significantly different products in the pyrolysis of PSD and PST because of the thermal lability of sulfur-containing compounds. However, the results obtained are not contradictory, and satisfactory mechanisms for the thermal degradation of PSD and PST have been derived from the overall evidence available. Pyrolysis compounds containing sulfur, styrene, and a number of cyclic styrene sulfides and diphenyldithianes have been observed by DPMS. However, in flash pyrolysis-GC/MS, styrene, sulfur, only one cyclic styrene sulfide, and two isomers of diphenylthiophene have been detected. These thiophene derivatives were indeed absent among the compounds obtained by DPMS because they were the terminal (most thermally stable) species arising from further decomposition of the cyclic styrene sulfides formed in the primary thermal degradation processes of PSD and PST. [References: 27]


523) Quantitative Determination of B(1-2) Cyclic Glucans by MALDI-MS

D.Garozzo, E.Spina, L.Sturiale, G.Montaudo, R.Rizzo

Rapid Communications in Mass Spectrometry  8(5),  358  - 1994

The use of matrix-assisted laser desorption/ionization mass spectrometry for the determination of the molecular weight distribution of cyclic beta (1-2) glucans is reported here. Quantitative response is demonstrated by the use of different instruments and by comparison with high-performance liquid chromatography/refractive index detection analysis.


524) Determination of Absolute Mass Values in MALDI-TOF of Polymeric Materials by a Method of Self-Calibration of the Spectra

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

Analytical Chemistry  66(23),  4366  - 1994

A novel calibration procedure is introduced that allows one to obtain absolute mass values in MALDI-TOF spectra of polymeric materials. The masses of the oligomers are written as the sum of two masses: mu(n) = sigma(n) + theta, where theta is the mass of the first oligomer and sigma(n) is a multiple of the polymer repeat unit and represents the distance in daltons from the first oligomer. The new calibration procedure considers theta as a variable parameter and performs a best-fit minimization. Two examples of application of the new procedure are given. Two synthetic polymers, poly(caprolactone) and poly(Bisphenol A carbonate), were analyzed by MALDI-TOF, and complex spectra showing one or more mass series up to 20 kDa were obtained. Application of this procedure allowed the interpretation of each single peak in the mass spectra and established that none of the peaks in the spectrum corresponds to fragments. It was found that the poly(caprolactone) sample consists of a series of oligomers with H and OH as terminal groups, which form sodium-cationized ions in the MALDI process. The composition of the poly(Bisphenol A carbonate) sample was more complex, since it contains a series of cyclic oligomers desorbing as sodium-cationized ions, plus two series of oligomers bearing H/phenol and phenyl/phenol as terminal groups, respectively, which form ions by capturing a proton in the MALDI process. [References: 11]


525) Self Calibrating Property of Matrix-assisted Laser Desorption/Ionization Time-of-flight Spectra of Polymeric Materials

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

Rapid Communications in Mass Spectrometry  8(12),  981  - 1994

A calibration procedure is introduced, which allows one to obtain absolute mass values in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) spectra of polymeric materials, thus avoiding ambiguous mass assignments, The method consists in combining the observed times of flight in a function denoted as 'modified sum of squares' (SS2) and in finding the point of minimum for SS2. The procedure takes advantage of the finding that SS2 possesses an extremum property, i.e. it takes its minimum at theta, the mass of the first oligomer appearing in the MALDI-TOF spectrum, The method was tested by recording the MALDI-TOF spectrum of an aminolyzed Nylon 6 and of a glycolized poly(butyleneadipate) (PEA) sample. Nylon 6 was found to be made of a series of oligomers bearing diaminohexamethylene (DAHM) terminal groups. PEA is made of a series of oligomers with butyleneglycol end-groups. The intense peaks seen in the mass spectra are due to sodium-cationized ions, whereas the less-intense peaks are due to potassium-cationized ions. The function SS2 was built for the two samples and a point of minimum was found at the point theta=817.6 for Nylon 6 and at the point theta=713,6 for PBA. This finding allowed the interpretation of the mass spectra. [References: 15]


526) 2-(4-Hydroxyphenylazo)-benzoic acid : A Solid Matrix for Matrix-assisted Laser Desorption/Ionization of Polystyrene

G.Montaudo, M.S.Montaudo, C.Puglisi, F.Samperi

Rapid Communications in Mass Spectrometry  8(12),  1011  - 1994

Liquid matrices are currently used in matrix assisted laser desorption ionization (MALDI) of non-polar macromolecules, such as polystyrene. We investigated the possibility of using non-liquid compounds as matrices. A series of polystyrene samples was analyzed by MALDI using a time-of-flight (TOF) analyzer. We found that a solid matrix, namely 2-(4-hydroxyphenylazo)-benzoic acid, yields quality mass spectra. The MALDI-TOF spectra were used to measure the parameters which characterize the molecular weight distributions of the polystyrene samples. The values obtained by MALDI-TOF were in good agreement with those obtained by other methods. [References: 12]


527) Ionic strength dependence of formation constants. XVII. The calculation of equilibrium concentrations and formation constants

C.De Stefano, P.Mineo, C.Rigano, S.Sammartano

Annali di Chimica  83,  343  - 1993

Calcn. methods for the study of equil. in soln., in non const. ionic strength conditions, are described. Two problems, in particular, are considered: (a) the calcn. of equil. concns., and, (b) the calcn. of formation consts. from potentiometric measurements. For these problems, 2 computer programs, BSTAC and ES4ECI, were written, and are discussed.


528) Structural Diversity in Xyloglucans from Higher-Plants - Spectroscopic Techniques for the Examination of the Structure and Metabolism of Xyloglucans

W.S.York, R.Guillen, G.Impallomeni, M.Hisamatsu, L.Kiefer, P.Albersheim, A.G.Darvill

Journal of Cellular Biochemistry  141  - 1993



529) Montecarlo Simulation of Copolymer Mass Spectra

M.S.Montaudo

Die Makromolekulare Chemie. Theory and Simulations  2,  735  - 1993

A computer program, MACO5, was developed which employs the Monte-Carlo approach to simulate the time-variation of the mass spectral peak intensities of a copolymer sample during the synthesis of an A/B copolyester via reactive blending of a mixture of homopolyesters A and B or when a copolymer undergoes partial degradation. The program was first used to simulate literature data consisting of a series of mass spectra of a butadiene/styrene copolymer subjected to partial ozonolysis. It was also used to investigate the role of terminal groups in reactive blending processes. Two models were developed: the first one describes inner-group ester-ester exchange reactions, the second describes the process in which an active terminal group attacks an ester group. The predictions of the two models are compared with recent experimental mass spectral data concerning a poly(ethylene adipate-co-ethylene terephthalate) copolyester


530) Montecarlo Modeling of Exchange Reactions in Polyesters. Dependence of Copolymer Composition from the Exchange Mechanism

M.S.Montaudo

Macromolecules  26(10),  2451  - 1993

Two models were developed which describe the synthesis of an A/B copolyester via reactive blending of a mixture of homopolyester A and homopolyester B. The models take into account two different exchange mechanisms: the first one describes inner-group ester-ester exchange, and the second describes the process in which an active terminal group attacks an ester group. The two models were incorporated in a computer program, MOSES, which simulates the exchange reaction using the Monte Carlo approach. The models yield different values for the composition of the copolymer formed: the first one predicts that the copolymer composition is always identical to the sample composition, whereas the second one predicts that deviations can occur in the initial stages of the process. This result can be used to discriminate between the two exchange mechanisms. The predictions of the two models are compared with recent experimental mass spectral data concerning a poly(ethylene adipate-co-ethylene terephthalate) copolyester. Comparison with experiment favors the active end group mechanism. The dependence of copolymer composition on reaction conditions was investigated using the MOSES program. From the overall set of concentration values calculated, a simple analytical formula was found (eq 9) which allows computation of the copolymer composition from the knowledge of the reaction conditions


531) Quantitative Applications of Matrix-Assisted Laser Desorption Ionization with Time-of-Flight Mass Spectrometry - Determination of Copolymer Composition in Bacterial Copolyesters

R.Abate, A.Ballistreri, G.Montaudo, D.Garozzo, G.Impallomeni, G.Critchley, K.Tanaka

Rapid Communications in Mass Spectrometry  7(11),  1033  - 1993

Poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) of microbial origin has been analyzed by matrix-assisted laser desorption/ionization (MALDI) in a time-of-flight mass spectrometer, after partial methanolysis, using two different instruments. Our results show that the mass spectral intensities recorded in the MALDI mode correlate with previously reported fast-atom bombardment and direct chemical ionization data. MALDI compares favourably with these other two techniques in that it is more suitable to the analysis of complex mixtures and of higher molecular masses.


532) Chemical Reactions Occurring the Thermal Treatment of Polymer Blends Investigated by Direct Pyrolysis Mass Spectrometry. Polycarbonate/Polybuthyleneterefthalate

G.Montaudo, C.Puglisi, F.Samperi

Journal of Polymer Science part A: Polymer Chemistry  31,  13  - 1993

The chemical reactions occurring in the thermal treatment of polycarbonate/polybuthyleneterephthalate (PC/PBT) blends have been investigated by gradual heating (10-degrees-C/min) using thermogravimetry and direct pyrolysis into the mass spectrometer. Exchange reactions occur already in the temperature range below 300-degrees-C but the transesterification equilibrium is affected by the evolution of thermal degradation products. Buthylenecarbonate, was detected in the first decomposition stage (320-380-degrees-C), which is evolved together with a series of cyclic compounds containing units of PC and PBT, in varying ratios. The overall thermal reaction evolves towards the formation of the most thermally stable polymer, i.e., a totally aromatic polyester (polymer III, Table I), which was found to be the end-product of the thermal processes occurring in the system investigated. The thermal decomposition products obtained from the PC/PBT blends in the range 320-600-degrees-C have mass sufficiently high to be structurally significant, since they contain at least one copolymer repeating unit. The reactions occurring in the thermal treatment of the PC/PBT blend are discussed in detail


533) Composition and Microstructure of a Copolyester Formed in the Melt Mixing of Polyethyleneterephthalate and Polyethylenetruxillate

G.Montaudo, M.S.Montaudo, E.Scamporrino, D.Vitalini

Die Makromoleculare Chemie  194,  993  - 1993

This study shows that is possible to determine the composition and microstructure of the copolyester formed in the melt-mixing process of poly(ethylene truxillate)a) (PETx) and poly-(ethylene terephthalate) (PET), by applying a novel method of statistical modeling of mass spectra of copolymers. The peak intensities of molecular ions appearing in the fast atom bombardment mass spectrum of the melt-mixed equimolar mixture of PETx and PET were found to reflect the relative amounts of oligomers present in the sample and to be directly related to the microstructure of the copolymer formed. The statistical analysis of copolymers allows one to generate a number of different theoretical mass spectra that can be fitted with the experimental mass spectrum data, thus determining the most likely copolymer composition. [References: 15]


534) Primary Thermal Degradation Mechanisms of PET and PBT

G.Montaudo, C.Puglisi, F.Samperi

Polymer Degradation and Stability  42(1),  13  - 1993

The primary thermal degradation mechanisms of polyethyleneterephthalate (PET) and polybutyleneterephthalate (PBT) have been studied by direct pyrolysis mass spectrometry using negative chemical ionization (NCI). The NCI mass spectra of PET and PBT are dominated by series of ions which might be assigned either to cyclic or open-chain oligomers with olefin and carboxylic end-groups. The structures of the pyrolysis products have been identified by comparison of their daughter ion spectra with those of authentic samples of cyclic and open-chain oligomers with olefin and carboxyl end-groups. The authors' results provide strong evidence that cyclic oligomers are the primary pyrolysis products of PET and PBT, formed by intramolecular exchange (ionic) reactions. These further decompose by a beta-CH hydrogen transfer reaction, which involves a six-membered cyclic transition state, and generates open chain oligomers with olefin and carboxylic end-groups. The pyrolysis of PET and PBT was also carried out in the presence of ammonium polyphosphate (APP) (an acid precursor). APP affects the pyrolysis by increasing the rate of decomposition and lowering the Polymer Decomposition Temperatures (PDT)s of both polymers. However, it does not change the nature of the compounds obtained in the pyrolysis of the pure polymers. This fact provides a firm argument in favour of the belief that the beta-CH hydrogen transfer occurs by an ionic process. [References: 60]


535) Fast-Atom-Bombardment Mass-Spectrometric Analysis of the Partial Ozonolysis Products of Poly(Isoprene) and Poly(Chloroprene)

G.Montaudo, E.Scamporrino, D.Vitalini, R.Rapisardi

Journal of Polymer Science part A: Polymer Chemistry  30,  525  - 1992

The low molecular weight compounds formed by partial ozonolysis of poly(isoprene) and poly(chloroprene) were analyzed by fast atom bombardment mass spectrometry (FAB-MS). In the poly(chloroprene) case, the ozonized mixtures were treated with piperidine before the MS analysis to transform in amide end groups the reactive acyl chlorides formed by the cleavage of double bonds along the main chain. Only one family of compounds having carboxyl and ketone or carboxyl and amide end groups were obtained from the ozonolysis of poly(isoprene) and poly(chloroprene), respectively. The assigned structures were confirmed by FAB-MS analysis of the GPC separated fractions [poly(chloroprene)] or by FAB-MS of the KOH-doped ozonolysis mixtures [poly(isoprene)]. It has been also ascertained, by GPC experiments, that poly(chloroprene) decomposes more rapidly than poly(isoprene) and poly(butadiene)


536) Main-Chain Porphyrin Polymers .1. Synthesis and Characterization of Polyethers Containing Porphyrin Units and Their Metal Derivatives

E.Scamporrino, D.Vitalini

Macromolecules  25(6),  1625  - 1992

The synthesis of four polyethers (I-IV) containing meso-tetraarylporphyrin units in the main chain is described. Two monomers, 5,10-bis(p-hydroxyphenyl)-15,20-bis(p-ethoxyphenyl)porphyrin (M1) and 5,10-bis(p-hydroxyphenyl)-15,20-bis(p-methoxyphenyl)porphyrin (M2), obtained by partial ethylation or methylation of tetrakis(p-hydroxyphenyl)porphyrin, were carefully separated from the other reaction products and characterized by H-1 NMR and FABMS analyses. In order to obtain macromolecules having flexible connections among porphyrin units along the polymer chain, the monomers M1 and M2 were treated with linear aliphatic dichlorides or dibromides of different molecular weight. The polyethers I-IV obtained were characterized by GPC, H-1 and C-13 NMR, and FABMS analyses. Their thermal stabilities were also examined. FABMS data about the inclusion of transition metals [cobalt(II), manganese(II), and zinc(II)] in the porphyrin units of polyethers III and IV are also reported. Our data show that in all the porphyrin units the two NH hydrogen atoms are substituted by one metal transition atom. So, polymers having a porphyrin units/metal ions ratio of 1 are always obtained


537) Determination of Sequence Distributions in Bacterial Copolyesters Containing Higher Alkyl and Alkenyl Pendant Groups

A.Ballistreri, G.Montaudo, M.Giuffrida, R.W.Lenz, Y.B.Kim, R.C.Fuller

Macromolecules  25(7),  1845  - 1992

The sequence distributions of microbial copolyesters produced by Pseudomonas oleovorans grown with (a) nonanoic acid (NA), (b) an equimolar mixture of NA and octanoic acid (OA), or (c) 2:1 mixtures of 10-undecenoic acid (UD) with either NA or OA were determined by analyzing the oligomers prepared by partial pyrolysis of these copolyesters using fast atom bombardment mass spectrometry. Oligomers up to tetramers were identified, and the amounts of these oligomers were used to calculate repeating unit compositions and sequence distributions. The sequence distributions in these copolyesters followed Bernoullian statistics, indicating that they were random copolymers. No ester exchange occurred during the pyrolysis


538) Thermal-Decomposition Processes in Bisphenol-A Polycarbonate

G.Montaudo, C.Puglisi

Polymer Degradation and Stability  37(1),  91  - 1992

A polemic. The claim of I. C. McNeil and A. Rinchon (ibid. 1991, 163, 31) that the primary thermal degrdn. of bisphenol A (I) polycarbonate occurs by free-radical process is unwarranted. Thermal cleavage of the polymer unit proceeds through an initial isomerization of the polymer chain followed by a disproportionation of the I unit to yield compds. with phenol and isopropenyl end-groups.


539) A Method for the Interpretation of Pyrolysis Mass-Spectra of Polyamides

M.Statheropoulos, C.G.Georgakopoulos, G.Montaudo

Journal of Analytical and Applied Pyrolysis  23(1),  15  - 1992

A new method for the interpretation of spectra from pyrolysis-mass spectrometry (Py-MS) of polyamides is proposed. The method consists of two steps: the examination of the general appearance of the spectrum with the determination of characteristic masses and the recognition of mass series. A list of characteristic mass peaks (mass markers) together with a table of mass series extracted from experimental data for pyrolysis are used to establish structure-masses relationships. The experimental conditions referring to both sample treatment and instrumentation are described. Examples of applications of the proposed method are presented


540) Further-Studies on the Composition and Microstructure of Copolymers by Statistical Modeling of Their Mass-Spectra

M.S.Montaudo, G.Montaudo

Macromolecules  25(17),  4264  - 1992

Statistical modeling of the mass spectral intensities of copolymers has been used to derive information on the distribution of monomers along the copolymer chain, and an automated procedure to find the composition and the sequence of the copolymers analyzed has been developed. A deconvolution method to determine the microstructure of copolymers when different chemical species contribute to the same mass spectral peak (that is, when a mass spectroscopic peak has an equivocal structural assignment) is presented. The effect of the partial degradation process on the mass spectra of copolymers is discussed, and a theory is given for the interpretation of the mass spectra of copolymers when the cleavage of the copolymer chain occurs by a selective or nonselective mechanism. A method is also reported to obtain the copolymer composition by direct analysis of the mass spectra. All these theories have been applied to determine the composition and microstructure of several copolymers (both addition and condensation types) whose mass spectra have been reported in the most recent literature


541) Structure of Underivatized Branched Oligosaccharides by Negative-Ion Fast-Atom-Bombardment Mass-Spectrometry

D.Garozzo, G.Impallomeni, G.Montaudo, E.Spina

Rapid Communications in Mass Spectrometry  6(9),  550  - 1992

We report here a study by negative-ion fast-atom bombardment (FAB) mass spectrometry of branched oligosaccharides containing a 3-O glycosidic linkage. Our results show that discrimination of the monosaccharide unit linked in the 3-O position is made possible by the analysis of the negative-ion FAB mass spectra. In the mass spectrum of A-trisaccharide (alpha-Fuc1-2-(alpha-GalNAc1-3)-Gal) the peak at m/z 307 can be explained as elimination of a neutral molecule of GaINAc (221 u) from the molecular ion. Also in the mass spectrum of 3-fucosyllactose (alpha-Fuc1-3-(beta-Gal1-4)-Glc) an intense peak at m/z 323, corresponding to the elimination of the fucose linked at the 3 position of glucose is present. To investigate further the fragmentations of the 3-O-linked sugars, the negative-ion FAB mass spectra of disaccharides have also been studied


542) Mechanism of Exchange in Polyesters - Composition and Microstructure of Copolymers Formed in the Melt Mixing Process of Poly(Ethylene-Terephthalate) and Poly(Ethylene Adipate)

G.Montaudo, M.S.Montaudo, E.Scamporrino, D.Vitalini

Macromolecules  25(19),  5099  - 1992

A study of the microstructure of the copolyesters formed in the exchange reactions which occur during the melt mixing of poly(ethylene adipate) (PEA) and poly(ethylene terephthalate) (PET) is reported. A PET sample stripped of the low molecular weight oligomers was melt-mixed with an equimolar amount of an PEA sample, and the exchange kinetics at 290-degrees-C was followed by analyzing the reaction mixture by H-1 NMR and FAB-MS. Mass spectra of partially aminolyzed melt-mixed samples were also examined. The copolyester initially formed in the exchange reaction proved to be a block copolymer containing an excess of EA units, as expected for a reaction proceeding by the attack of PEA on the PET chains. In the later stages of the exchange reaction, the copolyester microstructure was observed to approach a Bernoullian distribution and equimolar composition. The determination of the composition and microstructure of the copolyesters formed was attempted by NMR and mass spectra of the melt-mixed samples. This proved to be a difficult task by 200-MHz H-1 NMR spectroscopy, since only dyads were detected here because of the large repeating units in the copolymer. Instead, the FAB mass spectra showed series of oligomers up to the octamers, and the composition and microstructure of the copolyesters was monitored by applying some methods of statistical modeling of mass spectra of copolymers


543) 1991 Gordon Research Conference on Analytical Pyrolysis - Hampton-School, Nh, 22-28 June 1991

G.Montaudo

Journal of Analytical and Applied Pyrolysis  23(3),  215  - 1992



544) Structural Characterization of Butadiene Acrylonitrile Copolymers by Fast-Atom-Bombardment Mass-Spectrometric Analysis of the Partial Ozonolysis Products

D.Vitalini, E.Scamporrino

Polymer  33(21),  4597  - 1992

The partial ozonolysis of three random butadiene/acrylonitrile copolymers I-III, with butadiene contents of 78, 67 and 55 mol%, respectively, has been performed in order to form low-molecular-weight products by cleavage of double bonds along the main chain. The fragments thus obtained have been directly analysed by both positive and negative fast atom bombardment mass spectrometry (fa.b.-m.s.). According to a random distribution of butadiene (Bt) and acrylonitrile (AN) subunits in the copolymer chains, peaks due to fragments with different Bt/AN ratio in the molecule have been detected in the mass spectra. The relative abundances of the species having the same total number of AN and Bt subunits, detected in the mass spectra of ozonolysed copolymers I-III, have been compared with those calculated according to a theoretical combination of AN and Bt units. Good agreement has been found between the two sets of data. A graphical procedure for rapid determination of Bt/AN copolymer composition by f.a.b.-m.s. data has been also developed


545) Sequence Distribution of Beta-Hydroxyalkanoate Units in Bacterial Copolyesters Determined by Desorption Chemical Ionization Mass-Spectrometry

R.Abate, D.Garozzo, R.Rapisardi, A.Ballistreri, G.Montaudo

Rapid Communications in Mass Spectrometry  6(11),  702  - 1992

The sequence distributions of poly(beta-hydroxyalkanoate) copolymers were determined by analyzing oligomers obtained by the pyrolysis direct-chemical-ionization (DCI) mass spectrometry technique. Oligomers up to nonamers were identified and the comparison between the experimental and calculated peak intensities makes it possible to calculate repeating unit compositions and sequence distributions. Comparison with other earlier methods are given


546) Main Chain Porphyrin Polymers .2. Synthesis and Characterization of Some Copolyethers and Their Metal Derivatives

D.Vitalini, E.Scamporrino

Macromolecules  25(24),  6605  - 1992

Polycondensation between mixtures of 5,10-bis(p-hydroxyphenyl)-15,20-bis(p-ethoxyphenyl)-porphyrin (I) and Bisphenol A (BP-A) with dibromomethane was performed to obtain copolyethers III-VI which contain different amounts of porphyrin in the main chain. The resulting copolyethers were characterized by GPC, UV-visible, NMR, and FAB-MS analysis. Data on the inclusion of some transition metals in the porphyrin units of the copolymers are also reported


547) Complexing ability of pesticides and related compounds. Protonation of 1,2,4-triazole in aqueous solutions of sodium perchlorate and calcium chloride at different temperatures and ionic strengths

L.Abate, C.De Stefano, P.Mineo

Journal of Chemical Research-S  3,  76  - 1991

"The protonation of 1,2,4-triazole has been studied potentiometrically in aq. Solns. Of NaClO4 and CaCl2 at various temps., 10 ú T ú 45¦, and ionic strengths 0.1 ú I ú 1 mol dm-3; the behavior in different salt media is explained by a complex-formation model"


548) Structural Characterization of Butadiene Styrene Copolymers by Fast-Atom-Bombardment Mass-Spectrometry Analysis of the Partial Ozonolysis Products

G.Montaudo, E.Scamporrino, D.Vitalini

Macromolecules  24(2),  376  - 1991

The partial ozonolysis of some butadiene/styrene (Bt/St) copolymers has been performed in order to generate low molecular weight fragments by the cleavage of double bonds along the main chain. The mixtures obtained from ozonolysis were directly analyzed by fast atom bombardment mass spectrometry (FABMS). Compounds having aldehyde or carboxyl end groups have been detected, from which it has been possible to characterize the structure of the different copolymers investigated. The presence of compounds having aldehyde/aldehyde end groups and containing one ozonide unit in the molecule has been confirmed among the ozonolysis products of a Bt/St copolymer, by HPLC separation followed by FABMS analysis of the collected fractions. The ozonolysis kinetics has also been examined in order to value the extent of the ozonolysis reaction


549) Further-Studies on the Thermal-Decomposition Processes in Polycarbonates

G.Montaudo, C.Puglisi, R.Rapisardi, F.Samperi

Polymer Degradation and Stability  31(2),  229  - 1991

The thermal decomposition mechanisms of poly(trimethylene carbonate), poly(neopentylene carbonate), poly(2-phenyltrimethylene carbonate) and poly(p-xylylene carbonate) have been investigated by EI/CI direct pyrolysis mass spectrometry and by desorption chemical ionization (DCI) mass spectrometry. The results indicate that all four polycarbonates decompose by an intramolecular exchange, an ionic process that produces cyclic carbonates as pyrolysis products. Other thermal processes (Reactions 1c-1i, Scheme 1) also occur during the pyrolysis, and are all explained on the basis of well-established ionic reactions (Scheme 1)


550) Chemical-Reactions Which Occur in the Thermal-Treatment of Polycarbonate Polyethyleneterephthalate Blends, Investigated by Direct Pyrolysis Mass-Spectrometry

G.Montaudo, C.Puglisi, F.Samperi

Polymer Degradation and Stability  31(3),  291  - 1991

The chemical reactions which occur in the thermal treatment of polycarbonate/poly(ethyleneterephthalate) (PC/PET) blends have been investigated by gradual heating (10-degrees-C/min) using thermogravimetry and direct pyrolysis into the mass spectrometer. Exchange reactions occur even in the temperature range below 300-degrees-C, but the transesterification equilibrium is affected by the evolution of thermal degradation products. Ethylene carbonate was detected in the first decomposition stage (280-380-degrees-C), and is evolved together with a series of cyclic compounds containing units of PC and PET in varying ratios. The overall thermal reaction evolves towards the formation of the most thermally stable polymer, i.e. a totally aromatic polyester (polymer III, Table 1), which was found to be the end product of the thermal processes occurring in the system investigated. Several thermal decomposition products, originating from the PC/PET blends in the range 250-600-degrees-C, were identified. The compounds detected have masses sufficiently high to be structurally significant, since they contain at least one copolymer repeating unit. The reactions which occur during the thermal treatment of the PC/PET blend are discussed in detail


551) On the Mechanism of Thermal-Degradation of Polypivalolactone

D.Garozzo, G.Montaudo

Macromolecules  24(6),  1416  - 1991

Evidence is presented for the formation of cyclic oligomers, obsd. at relatively large intensities by direct pyrolysis-CI mass spectrometry. This suggests that they are primary thermal degrdn. products generated by a chain-end initiated, intramol. exchange mechanism. This conclusion is offered as an alternative to the proposal of L. E. Manring et al. (1990), which states that the thermal degrdn. of polypivalolactone proceeds by a stepwise living process.


552) Microstructure of Bacterial Poly(Beta-Hydroxybutyrate-Co-Beta-Hydroxyvalerate) by Fast-Atom-Bombardment Mass-Spectrometry Analysis of the Partial Pyrolysis Products

A.Ballistreri, G.Montaudo, D.Garozzo, M.Giuffrida, M.S.Montaudo

Macromolecules  24(6),  1231  - 1991

The microstructure of poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) (P(HB-co-HV)) has been studied by mass spectrometry. We describe a novel method for the structural analysis of P(HB-co-HV) copolymers, based on the direct FAB-MS analysis of the partial pyrolysis products. The FAB spectra obtained allow the identification of the copolymer microstructure up to the hexads level, and a comparison between the experimental and calculated peak intensities makes it possible to discern clearly if the sample is made of a single random copolymer or of a mixture of two random copolymers. In addition, an algorithm has been developed that also allows the determination of both the amount of the random copolymers in the binary P(HB-co-HV) mixtures, as well as the copolymer composition of the individual copolymers. The highly discriminating power of the method developed here is due to the possibility of fitting the calculated statistical abundances with the MS experimental values corresponding to higher oligomers, i.e., hexamers as compared to diad and triad monomer sequences seen by C-13 NMR


553) The Structure of Plant-Cell Walls .31. A New Undecasaccharide Subunit of Xyloglucans with 2 Alpha-L-Fucosyl Residues

M.Hisamatsu, G.Impallomeni, W.S.York, P.Albersheim, A.G.Darvill

Carbohydrate Research  211(1),  117  - 1991

A new oligosaccharide subunit of xyloglucan was isolated from the beta-(1-->4)-endoglucanase digestion products of the xyloglucan in what is referred to as ''sycamore extracellular polysaccharides'' and found to be an undecasaccharide having two terminal alpha-L-fucopyranosyl residues. The undecasaccharide was structurally characterized by H-1-n.m.r. spectroscopy, fast-atom bombardment mass spectrometry (f.a.b.-m.s.), and glycosyl-residue and glycosyl-linkage composition analyses. The structure of the undecasaccharide was confirmed by digesting it with a hydrolase that releases alpha-D-Xylp-(1-->6)-D-Glc from the non-reducing end of xyloglucan oligosaccharides


554) Evolution of Aromatics in the Thermal-Degradation of Poly(Vinyl Chloride) - A Mechanistic Study

G.Montaudo, C.Puglisi

Polymer Degradation and Stability  33(2),  229  - 1991

"Various aspects of the thermal decomposition, flammability and smoke evolution from PVC have been investigated in an attempt to account for the mechanism of evolution of aromatics from this polymer. The most relevant experimental observations for the understanding of the mechanism of thermal decomposition of PVC were obtained by the method of direct pyrolysis in the mass spectrometer. A number of facts that had partly escaped previous workers was revealed: that in each of the two degradation steps of PVC a family of aromatic hydrocarbons was formed with different structures; that the two families of aromatics are suppressed at considerably different rates by the addition of metal oxides. The selective suppression of aromatics is related to the fact that the two families of aromatics are evolved from linear and from crosslinked polyene chains, respectively. Another conclusion is that the intramolecular cyclization processes in linear and crosslinked polyenes are satisfactorily explained by the cyclization of polyene radicals, whereas mechanisms based solely on Diels-Alder processes meet with several difficulties. The close analogy found with the thermal degradation of polyacetylene supports these conclusions. Another model system is provided by PVC2 and PVF2. These vinylidene polymers do not form alkyl-aromatics, only unsubstituted aromatics are evolved and the thermal degradation occurs in a single stage"


555) The Interpretation of Pyrolysis Mass-Spectra of Polymers Using A Hybrid Software System Based on Library Searching with Heuristics

M.Statheropoulos, C.G.Georgakopoulos, G.Montaudo

Journal of Analytical and Applied Pyrolysis  20,  65  - 1991

The development of a 'hybrid' software system for the interpretation of pyrolysis mass spectra of condensation polymers is presented. Pyrolysis mass spectra acquired with various ionization techniques and ionization energies are used. The spectral interpretation algorithms are based on library search and retrieval using heuristics. The library, which is actually a data base, organizes information in hierarchical and encoded form on name, type, structural units, pyrolysis products and pyrolysis mass spectra of the polymers. The various stages of interpretation are outlined


556) Ionia - An Expert System for the Prediction of the Thermal-Decomposition of Condensation Polymers

M.Statheropoulos, G.Montaudo

Journal of Analytical and Applied Pyrolysis  20,  57  - 1991

The production-system language OPS5 implemented in LISP with the MEA strategy and the RETE match algorithm is used for developing the Expert System (ES) IONIA. This is an ES for the prediction of thermal degradation processes, temperature of thermal degradation and degradation products of condensation polymers. The prediction is based on the structure of the polymers. The prototype for polyurethanes and polyureas is outlined as an example of how the system is functioning. The knowledge base used, both the chemical rules and the meta-rules, are discussed. The system makes an enhancement and change of the knowledge base possible. The advantages of IONIA in practical applications are presented


557) Determination of Microstructure in Copolymers - Statistical Modeling and Computer-Simulation of Mass-Spectra

M.S.Montaudo, A.Ballistreri, G.Montaudo

Macromolecules  24(18),  5051  - 1991

The recent finding that significant information on copolymer microstructure can be obtained by using mass spectrometry has stimulated our work toward developing appropriate algorithms to match the experimental mass spectra to those theoretically calculated. A novel program for the determination of microstructure in copolymers by computer simulation of mass spectra is reported. The statistical model used to describe copolymer distributions is reported in detail in the text. The computer simulation program (MACO3) is discussed, and three illustrative examples are given


558) Microstructure of Copolymers by Fast-Atom-Bombardment Mass-Spectrometry

G.Montaudo

Rapid Communications in Mass Spectrometry  5(3),  95  - 1991

The assumption on which both the structural analysis of polymers and the sequential analysis of co-polymers by fast-atom bombardment mass spectrometry (FAB-MS) is based, is that the ions detected in the FAB spectra do originate from species already present in the polymeric samples, and that the bombardment by fast atoms does not produce the fragmentation of macromolecules. FAB spectra do not yield direct structural information on large macromolecules, but such information can be deduced from the structural analysis of relatively low molecular weight species. Therefore, in a series of recent studies, FAB-MS has been used to identify the oligomers formed in the partial degradation of several co-polymers, and the results obtained have yielded detalied information on the microstructure of the materials investigated


559) Mass-Spectral Determination of Cyclic Oligomer Distributions in Polymerization and Degradation Reactions

G.Montaudo

Macromolecules  24(21),  5829  - 1991

Mass spectral data have been directly used for the first time to determine the distributions of cyclic oligomers formed during polymerization and degradation reactions. In the text are presented several cases illustrating polymerization and thermal degradation reactions occurring in polyesters, polyamides, and polysulfides. The experimental distributions of cyclic oligomers allow discrimination between thermodynamically and kinetically controlled cyclization processes. In the former case the cyclic oligomer concentration decreases with n-2.5, and in the latter with n-1.5. The exponent in the cycle distribution law indicates therefore if the cyclization process is occurring through a back-biting or an end-biting reaction


560) Linkage Analysis in Disaccharides by Electrospray Mass-Spectrometry

D.Garozzo, G.Impallomeni, E.Spina, B.N.Green, T.Hutton

Carbohydrate Research  221(1),  253  - 1991

The electrospray mass spectrometry of (1.fwdarw.2)-sophorose, (1.fwdarw.3)-laminaribiose, (1.fwdarw.4)-cellobiose, (1.fwdarw.6)-gentiobiose, and maltose are reported. Each mass spectrum contains peaks assocd. with fragmentations which involve the glycosidic linkages and reflect the positions of the linkages. Electrospray ionization thus permits linkage anal. without resorting to tandem mass spectrometry.


561) A new undecasaccharide subunit of xyloglucans with two a-L-fucosyl residues

M.Hisamatsu, G.Impallomeni, W.S.York, P. Albersheim, A.G.Darvill

Carbohydrate Research  211(1991),  117  - 1990

A new oligosaccharide subunit of xyloglucan was isolated from the Beta-(1-->4)-endoglucanase digestion products ofthe xyloglucan in what is referred to as "sycamore extracellular polysaccharides" and found to be an undecasaccharide having two terminaI a-L-fucopyranosyl residues. The undecasaccharide was structurally characterized by H-n.m.r. spectroscopy, fast-atom bombardment mass spectrometry (f.a.b.m.s.), and glycosyl-residue and glycosyl-linkage composition analyses. The structure ofthe undecasaccharide was confirmed by digesting it with a hydrolase that releases alfa-D-Xylp-(1-->6)-D-Glc from the nonreducing end of xyloglucan oligosaccharides.


562) Determination of Linkage Position and Identification of the Reducing End in Linear Oligosaccharides by Negative-Ion Fast Atom Bombardment Mass-Spectrometry

D.Garozzo, M.Giuffrida, G.Impallomeni, A.Ballistreri, G.Montaudo

Analytical Chemistry  62(3),  279  - 1990

Neg. ion fast-atom-bombardment (FAB) mass spectra allowed the detn. of the linkage position and sugar sequences in a series of (underivatized) disaccharides and of linear oligosaccharides. Discrimination of 1-4, 1-6, 1-3, and 1-2 linkage type and detn. of the reducing end and of the monosaccharide sequence is made possible by the anal. of the neg. metastable ions produced in linked scans FAB MS. The peculiarity of neg. ionization is believed to consist in a selective deprotonation of the anomeric hydroxyl (reducing end of the oligosaccharide chain), which is more acidic with respect to the remaining OH groups. Once the neg. charge is localized at the oligosaccharide reducing end, the ion fragmentation of this ring occurs rapidly and the mass losses obsd. are found to be diagnostic of the glycoside linkage type between adjacent sugar units. The overall neg. ions fragmentation process outlined above allows the simultaneous identification of the reducing end of the chain, of the monosaccharide units sequence, and of the linkage type between adjacent units.


563) Odd-Electron Molecular Ion and Loss of Toluene in Fast Atom Bombardment Mass-Spectra of Some Carotenoids

S.Caccamese, D.Garozzo

Organic Mass Spectrometry  25(3),  137  - 1990

Pos.-ion fast atom bombardment (FAB) and B/E linked scan FAB mass spectra of seven carotenoids are reported. In all cases the M+.bul. ions are obsd., and the [M + H]+ ions are absent in the hydrocarbons and weak in the oxygenated compds. The usefulness of B/E linked scan FAB mass spectra to distinguish isomers and to attribute the loss of toluene from the M+.bul. to an ionic fragmentation and not to a thermal process is discussed.


564) Polymerization of Nitro-Compounds on Silver Surfaces During Surface-Enhanced Raman-Scattering

W.H.Tsai, F.J.Boerio, S.J.Clarson, G.Montaudo

Journal of Raman Spectroscopy  21(5),  311  - 1990

Surface-enhanced Raman scattering (SERS) was obsd. from thin films formed by 1,4-dinitrobenzene (I) and 1,3-dinitrobenzene (II) spin-coated onto silver island films from dil. solns. During laser irradn. of I films on silver substrates at relatively high laser powers, new bands appeared near 1152, 1350, 1412 and 1460 cm-1 and bands near 1118, 1358 and 1372 cm-1 decreased in intensity. A band near 1598 cm-1 shifted to near 1605 cm-1. The bands near 1152 and 1412 cm-1 were assigned to stretching modes of .vphi.-N and -N:N-bonds of azo compds., resp., indicating that polymn. of I had occurred. The extent of polymn. was greatest when the surface coverage of adsorbed I was greatest and when the SERS expts. were carried out in a N atm., indicating that reducing conditions were required for the polymn. No polymn. was obsd. for II under similar circumstances. The difference was attributed to orientation of the adsorbed species. It was concluded that I was adsorbed with a horizontal configuration in which the arom. rings were parallel to the substrate surface and both nitro groups were in contact with the surface while II was adsorbed wtih a vertical configuration in which the rings were perpendicular to the surface and only one nitro group was in contact with the surface.


565) Sequence Distribution of Beta-Hydroxyalkanoate Units with Higher Alkyl-Groups in Bacterial Copolyesters

A.Ballistreri, G.Montaudo, G.Impallomeni , R.W.Lenz,Y.B.Kim, R.C.Fuller

Macromolecules  23(24),  5059  - 1990

"Two different samples of copolyesters produced by Pseudomonas oleovorans, when grown either on nonanoic acid (I) alone or on an equimolar mixt. Of I and octanoic acids, were evaluated for sequence distribution by controlled methanolysis to their oligomers; sepn. Of the oligomers by HPLC, and anal. Of the fractions so obtained by fast atom bombardment mass spectrometry, was performed. The copolyesters contained primarily .beta.-hydroxyheptanoate and .beta.-hydroxynonanoate units, which showed no observable differences in their 1H and 13C-NMR spectra with changes in compn., so those analyses could not be applied. The obsd. Oligomer compn. And that calcd. On the basis of Bernoullian statistics for sequence distributions in random copolymers of the compns. Studied were in good agreement."


566) Primary thermal decomposition processes in aliphatic polyamides

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Impallomeni, G.Montaudo

Polymer Degradation and Stability  23(1),  25  - 1989

The primary thermal decompn. processes of a series of aliph. polyamides were investigated by direct chem. ionization and tandem mass spectrometry. Intramol. exchange process was the preferred thermal decompn. mechanism for many of the polyamides. Decompn. through a C-H H transfer reaction occurred as a secondary thermal process, except in the case of nylon 3 because of its particular structure. A quite different decompn. pathway was followed by nylons from adipic acid (nylons 6.6 and 11.6), where specific structural factors made the formation of cyclopentanone preferred. These polymers decompd. via a C-H H transfer to N with the formation of compds. having amine and/or ketoamide end groups.


567) Characterization of copolymer sequences by fast atom bombardment mass spectrometry. 2. Identification of oligomers contained in alternating and random copolyesters with photolabile units in the main chain

G.Montaudo, E.Scamporrino, D.Vitalini

Macromolecules  22(2),  627  - 1989

The mass spectra of bis(2-hydroxyethylene) terephthalate-.alpha.-truxilloyl chloride (I) copolymer and ethylene glycol-terephthaloyl chloride-I copolymer were obtained to det. the chain structure. Sequence lengths at the heptad level were detected.


568) Characterization of copolymer sequences by fast atom bombardment mass spectrometry. 1. Identification of oligomers produced in the hydrolysis and photolysis of random copolyamides containing photolabile units in the main chain

G.Montaudo, E.Scamporrino, D.Vitalini

Macromolecules  22(2),  623  - 1989

The mass spectra of hydrolyzed and photolyzed adipoyl (I)-.alpha.-truxilloyl chloride (II)-piperazine (III) copolymer as well as I-II and II-III copolymer showed peaks up to 2000 daltons. Oligomers having cinnamoyl end groups were detected in the photolyzed copolymers, while oligomers having piperazinyl, truxilloyl, and/or adipoyl end groups were detected in the hydrolyzed copolymers.


569) Sequencing bacterial poly(β-hydroxybutyrate-co-β-hydroxyvalerate) by partial methanolysis, HPLC fractionation, and fast-atom-bombardment mass spectrometry analysis

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Impallomeni, G.Montaudo

Macromolecules  22(5),  2107  - 1989

The partial methanolysis of poly(β.-hydroxybutyrate) (I) and of poly(β-hydroxybutyrate-co-β-hydroxyvalerate) (II) was performed, and reaction kinetics was optimized to produce oligomers with mol. wts. below the detection limit (.apprx.2000) of the mass spectrometer used for the subsequent anal. The fractionation of the methanolysis products was achieved by HPLC, and the fractions collected were analyzed by fast-atom-bombardment mass spectrometry (FAB-MS) in the presence of NaCl. FAB spectra of oligomers from I and II consisted only of pseudomol. ions MH+ and MNa+, allowing for identification of the methanolysis products, estn. of the copolymer compn., and the detn. of the sequence distribution.


570) Metal-catalyzed oxidation of poly(.alpha.-methylstyrene) during surface-enhanced Raman scattering

F.J.Boerio, W.H.Tsai, G.Montaudo

Journal of Polymer Science Part B-Polymer Physics  27,  1017  - 1989

Surface-enhanced Raman scattering (SERS) was used to characterize thin films of poly(.alpha.-methylstyrene) (I) spin-coated onto Ag island films supported by glass substrates. At laser powers of a few tens of milliwatts, SERS spectra of thin films of I (.apprx.100 .ANG.) were weak, and only the bands near 1010 and 1040 cm-1 were obsd. At laser powers of .apprx.100 mW, addnl. bands characteristic of I were obsd. near 720 and 1610 cm-1. However, oxidative degrdn. of the I films to form graphite-like substances was also obsd. at the higher laser powers. When the thickness of the I films was increased to several hundred angstroms, degrdn. of the films was inhibited, but the intensity of the Raman scattering remained const., indicating that the obsd. SERS was an interfacial rather than bulk effect. Degrdn. during SERS expts. was also inhibited by overcoating I films with much thicker films of poly(4-styrenesulfonate) (II). Scattering from the II overlayers was not obsd. as long as the thickness of the PMS films was greater than several tens of angstroms, again showing that the SERS was an interfacial effect. Oxidative degrdn. of the I films was also inhibited by adding a few percent of the antioxidant 2,6-di-tert-butyl-4-methylphenol to the polymer. Bands related to sulfite contaminants adsorbed onto the Ag island films were obsd. near 640 and 940 cm-1. These bands disappeared when II, but not I, was spin-coated onto the SERS substrates, indicating a strong interaction between II and Ag.


571) Organotin-mediated synthesis of macrocyclic tetraesters. A combined proton NMR spectroscopy, gel permeation chromatography, and fast atom bombardment mass spectrometry approach to complete product analysis

L.Mandolini, G.Montaudo, E.Scamporrino, S.Roelens, D.Vitalini

Macromolecules  22(8),  3275  - 1989

Mixts. of cyclic oligomer were prepd. from 2,2-dibutyl-1,3,2-dioxastannolane and sebacoyl chloride, adipoyl chloride, glutaroyl chloride, or diglycoloyl chloride. Anal. of the mixts. was done by 1H NMR, gel-permeation chromatog., and fast-atom-bombardment mass spectroscopy.


572) Thermal degradation processes in aliphatic polydithiocarbonates

G.Montaudo, C.Puglisi, C.Berti, E.Marianucci, F.Pilati

Journal of Polymer Science part A: Polymer Chemistry  27,  2277  - 1989

The thermal degrdn. of three aliph. polythiocarbonates was investigated by direct pyrolysis in the ion source of a mass spectrometer operating both in electron and chem. ionization modes. The overall evidence indicated that these polymers start decompg. at about 250-280.degree. by an end-biting process initiating from the SH end-groups, which produced a mixt. of cyclic sulfides, disulfides, and dithiocarbonates. Another decompn. step was obsd. at higher temp. (ca. 350-370.degree.), producing essentially the same compds. evolved in the first stage, but with significant differences in their relative abundances. An intramol. exchange (back-biting) process was believed to be responsible for the second thermal decompn. stage.


573) Sequencing an aromatic copolycarbonate by partial ammonolysis and FAB-MS analysis of the products

G.Montaudo, C.Puglisi, F.Samperi

Polymer Bulletin  21(5),  483  - 1989

Fast-atom bombardment mass spectrometry (FAB-MS) was used to identify the low-mol.-wt. compds. produced in the partial piperidine aminolysis of an essentially alternating copolycarbonate contg. resorcinol and bisphenol A (I) units. The FAB-MS spectra allowed identification of sequences with an exactly alternating structure. Some spurious sequences contg. blocks of 2-4 consecutive I units were also detected.


574) Thermal decomposition processes in aromatic polythiocarbonates

G.Montaudo, C.Puglisi, C.Berti, E.Marianucci, F.Pilati

Journal of Polymer Science part A: Polymer Chemistry  27,  2657  - 1989

The thermal degrdn. of some polythiocarbonates obtained from bisphenol A bischloroformate and dithiols was investigated by thermogravimetry and by direct pyrolysis in the mass spectrometer operating both in electron and chem. ionization. Poly(bisphenol A trimethylenedithiocarbonate) decompd. by an intramol. exchange process (back-biting) producing trimethylene-1,3-dithiocarbonate and bisphenol A polycarbonate. Polymers contg. tetramethylene-1,4-dithiocarbonate and hexamethylene-1,6-dithiocarbonate units decompd. by the same mechanism, but the elimination of the dithiocarbonate units was not as fast and selective as the previous case. Poly(phenylene-1,3-dithiocarbonate) decompd. by CO and COS loss with formation of sulfide and disulfide bridges along the polymer chains, which underwent further thermal degrdn. by a back-biting process yielding a series of cyclic compds. The thermal degrdn. of poly(bisphenol A phenylenedithiocarbonate) took place through an interchange reaction producing phenylene-1,3-dithiocarbonate sequences which further decompd. as the corresponding polymer.


575) Selective oxidation of para-substituted polystyrenes during surface-enhanced Raman scattering

F.J.Boerio, W.H.Tsai, P.P.Hong, G.Montaudo

Macromolecules  22(10),  3955  - 1989

Selective oxidn. of para-substituted polystyrene films on Ag substrates was obsd. during surface-enhanced Raman scattering. Primary oxidn. occurred by a Norrish type II reaction, resulting in chain scission and the formation of aryl ketone and olefin end groups. When the substituent in the para position was electron donating, as in the case of poly(4-fluorostyrene), poly(4-chlorostyrene), poly(4-bromostyrene), and poly(4-methylstyrene), further oxidn. occurred rapidly by a Norrish I reaction, resulting in formation of para-substituted benzoic acids. Further oxidn. took place by a Diels-Alder addn. process between the aryl ketone and olefin end groups, ultimately leading to the formation of graphitelike species.


576) Structural characterization of copolyesters by fast atom bombardment mass spectrometry analysis of the partial ammonolysis products

G.Montaudo, E.Scamporrino, D.Vitalini

Die Makromolekulare Chemie, Rapid Communications  10,  411  - 1989

The structures of poly(ethylene terephthalate) and ethylene glycol-terephthaloyl chloride-a-truxilloyl chloride copolymer were detd. by aminolysis with piperidine, followed by fast-atom-bombardment mass spectrometry. Aminolysis allowed identification of sequences contg. several comonomer subunits and characterization of random structures.


577) Synthesis and structural characterization by fast-atom-bombardment mass spectrometry of exactly alternating copolyesters containing photolabile units in the main chain

G.Montaudo, E.Scamporrino, D.Vitalini

Polymer  30(2),  297  - 1989

Polycondensation between bis(2-hydroxymethylphenyl) adipate, bis(3-hydroxypropylene) terephthalate and bis(2-hydroxyethylene) terephthalate with .alpha.-truxilloyl chloride were performed to obtain exactly alternating copolyesters contg. photoreactive cyclobutane units in the main chain. The resulting copolyesters were characterized by fast-atom bombardment (f.a.b.) mass spectrometry, and the structure of the oligomers detected in the f.a.b.(+) and f.a.b.(-) mass spectra allowed confirmation of the alternating sequence present in the copolymers.


578) Analytical degradation: an approach to the structural analysis of microbial polyesters by different methods

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Impallomeni, G.Montaudo

Journal of Analytical and Applied Pyrolysis  16(3),  239  - 1989

"A sample of pure poly(.beta.-hydroxybutyrate) (I) and a sample of 87:13 .beta.-hydroxybutyrate-.beta.-hydroxyvalerate copolymer (II) were investigated by different degrdn. Methods: (a) direct pyrolysis-mass spectrometry; (b) fast-atom-bombardment mass spectrometry (FABMS) anal. Of the partial pyrolysis products; and © FABMS anal. Of the partial methanolysis products. The pyrolysis products originating from I and II are thermally labile, so that oligomers higher than the trimer cannot distill undecomposed and remain undetected by electron impact or chem. Ionization MS. However, the pyrolysis products can be desorbed by FABMS up to the decamer level. With the partial pyrolysis method it is not possible to obtain reliable compn. And sequence distribution data, which may, however, be obtained by the FABMS anal. Of the partial methanolysis products of I and II."


579) Thermal decomposition processes in polycarbonates

G.Montaudo, C.Puglisi, F.Samperi

Polymer Degradation and Stability  26(3),  285  - 1989

The thermal decompn. mechanisms of some polycarbonates were studied by direct pyrolysis mass spectrometry. Aliph. polycarbonates decompd. by intramol. exchange processes which produce cyclic compds. as primary pyrolysis products. Aliph.-arom. polycarbonates yielded cyclic compds. contg. various ratios of bisphenol A (I) and aliph. carbonates. Bisphenol A bischloroformate-resorcinol copolymer underwent ester-exchange rearrangement to produce cyclic resorcinol carbonate oligomers and I polycarbonate.


580) Thermal degradation of new copolymers from pyromellitic anhydride

G.Montaudo, C.Puglisi, N.Bicak, A.Orzeszko

Polymer  30(12),  2237  - 1989

Polyester-polyimides and polyamide-polyimides were synthesized from bis(N-chlorocarbonylmethyl)pyromellitimide with diols and diamines, resp. A polyamine-polyimide was obtained from bis(N-allyl)pyromellitimide and piperazine via the Michael reaction. The thermal degrdn. of the polyimides was studied by direct pyrolysis mass spectrometry.


581) Determination of linkage position in disaccharides by negative-ion fast-atom bombardment mass spectrometry

A.Ballistreri, G.Montaudo, D.Garozzo, M.Giuffrida, G.Impallomeni

Rapid Communications in Mass Spectrometry  3(9),  302  - 1989

Neg.-ion fast-atom bombardment linked-scan spectra at const. B/E allow differentiation of the linkage position in hexose-hexose disaccharides. Sequence information can also be obtained when there is a mol. wt. difference between the monosaccharide units in the carbohydrate mol.


582) Pyrolysis-mass spectrometry of copolymers of 2-vinylnaphthalene with methyl acrylate and methyl maleate

G.Montaudo, C.Puglisi, D.Vitalini, Y.Morishima

Journal of Analytical and Applied Pyrolysis  13(3),  161  - 1988

The thermal degrdn. of maleic anhydride-2-vinylnaphthalene (I) alternating copolymer Me ester and acrylic acid-I copolymer Me ester was studied by direct pyrolysis-mass spectrometry using electron ionization and chem. ionization. The polymers decompd. through 2 competitive mechanisms: a random main chain cleavage reaction and a MeOH elimination reaction from the side chain with formation of lactone units.


583) Fast-atom-bombardment mass spectrometry identification of oligomers contained in polysulfides and their complexes with heavy metals

G.Montaudo, E.Scamporrino, C.Puglisi, D.Vitalini

Macromolecules  21(6),  1594  - 1988

Cyclic oligomeric poly(trimethylene sulfide), poly(hexamethylene sulfide), poly(m-phenylene sulfide), and poly(m-phenylene hexamethylene sulfide) with mol. wt.


584) An iron-organic polymeric smoke suppressant for poly(vinyl chloride)

E.W.Neuse, J.R.Woodhouse, G.Montaudo, C.Puglisi

Applied Organometallic Chemistry   2,  53  - 1988

The incorporation of a poly[ferrocene-1,2(1, 3:1, 1')diylmethylene] fraction with .hivin.Mn = 2100 as a smoke suppressant additive into both unplasticized and bis(2-ethylhexyl) phthalate-plasticized, CaCO3-filled PVC compns. entails appreciable redns. in smoke evolution during combustion tests relative to unmodified formulations. The best results, with smoke d. redns. in the range 25-80%, are obtained at the 3% loading level, with higher additive concns. causing no further improvements. The findings of this study may have implications on the design of other polymeric engineering materials exposed to potential fire hazards.


585) Primary thermal fragmentation processes in poly(ethylene oxalate) investigated by mass spectrometry

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Impallomeni, G.Montaudo

Polymer Degradation and Stability  21(4),  311  - 1988

The primary thermal decompn. mechanism of poly(ethylene oxalate) (I) was investigated by pyrolysis-mass spectrometry. Several mass spectrometric techniques were used to identify compds. present in the pyrolysis mixt.: comparison of electron impact and chem. ionization spectra, high-resoln. accurate mass measurements, and tandem mass spectrometry (daughter- and parent-ion spectra). The results obtained indicate that intramol. exchange reactions predominate in the primary thermal fragmentation processes yielding cyclic oligomers up to tetramer. I, prepd. by condensation polymn., was shown by 1H-NMR to contain 7% of diethylene glycol (II) units along the polymer chain. A small amt. of cyclic oligomers contg. II units was detected among the pyrolysis products from I.


586) Intumescent flame retardants for polymers. IV. The polycarbonate-aromatic sulfonates system

A.Ballistreri, G.Montaudo, E.Scamporrino, C.Puglisi, D.Vitalini, S.Cucinella

Journal of Polymer Science part A: Polymer Chemistry  26,  2113  - 1988

The mechanism of action of arom. sulfonates as flame retardants (FR) on bisphenol A polycarbonate (PC) was investigated. These compds. were capable of inducing a self-extinguence in PC even when present in very low amts. (0.2-1%). Thermogravimetric and flash pyrolysis/gas chromatog./mass spectrometry data showed the thermal degrdn. rate of PC enhanced, and the distribution of the volatile pyrolysis products was modified by these additives. Oxygen index and N2O index measurements indicated a FR condensed-phase mechanism of these additives. Traces of polymer surface temp. against time, measured under forced flame conditions, showed that the expanded carbon layer formed in the combustion of PC-arom. sulfonate blends produced a heat insulating effect toward the undecomposed bulk. The overall evidence showed that arom. sulfonates caused the flame extinguishment in PC by an intumescent phenomenon.


587) Current problems in pyrolysis

G.Montaudo

Journal of Analytical and Applied Pyrolysis  13(1-2),  1  - 1988



588) Thermal decomposition processes in polyhydrazides and polyoxamides investigated by mass spectrometry

A.Ballistreri, D.Garozzo, G.Montaudo, A.Pollicino, M.Giuffrida

Polymer  28(1),  139  - 1987

The thermal decompn. processes of some totally arom. or totally aliph. polyhydrazides and polyoxamides were studied by direct pyrolysis mass spectrometry, using both chem. ionization and electron impact modes. The results indicate that the primary thermal decompn. processes of these polymers (contg. -CO-CO- and -NR-NR- linkages) are strongly influenced by structural factors.


589) Mass spectrometric characterization of poly(ethylene terephthalate-co-p-oxybenzoate)

D.Garozzo, M.Giuffrida, G.Montaudo, R.W.Lenz

Journal of Polymer Science part A: Polymer Chemistry  25,  271  - 1987

p-Acetoxybenzoic acid-ethylene glycol-terephthalic acid copolymer [52237-98-6] samples having various compns. were examd. by direct pyrolysis-mass spectrometry to det. the thermal stabilities and the sequence distributions of the oxybenzoate and ethylene terephthalate units as a function of compn. Thermal stability as measured by the rate of volatilization increased with increasing oxybenzoate content, as did the amt. of char residue formed. The electron-impact mass spectra of volatile fragments showed the formation of predominantly linear fragments with COOH and vinyl end groups. Dimer, trimer, and tetramer fragments contg. either or both types of units were identified and their relative amts. were estd. from peak intensities. The results were consistent with those expected for random distributions of the 2 units, i.e., for statistical copolymers.


590) Thermal decomposition processes in aliphatic polysulfides investigated by mass spectrometry

G.Montaudo, E.Scamporrino, C.Puglisi, D.Vitalini

Journal of Polymer Science part A: Polymer Chemistry  25,  475  - 1987

The thermal degrdn. of polythiomethylene (I) [24938-55-4], polythiotrimethylene [28758-48-7], polythioethylene [24936-67-2], and polythiohexamethylene [57514-74-6] was investigated by direct pyrolysis in the ion source of a mass spectrometer (DPMS) operating both in electron impact and chem. ionization modes. Flash-pyrolysis gas chromatog.-mass spectrometry was also used in the case of I to confirm the DPMS results. The overall evidence indicates that the primary thermal decompn. of these polymers yields cyclic sulfides by an intramol. exchange process. A .beta.-CH hydrogen transfer reaction, occurring in parallel with the former process, produces primary pyrolysis compds. with SH end-groups.


591) Thermal decomposition processes in aliphatic-aromatic polysulfides investigated by electron impact and chemical ionization mass spectrometry

G.Montaudo, E.Scamporrino, C.Puglisi, D.Vitalini

Polymer  28(3),  477  - 1987

The thermal degrdn. of four aliph.-arom. polysulfides was investigated by direct pyrolysis in the ion source of a mass spectrometer operating both in electron impact and chem. ionization modes. The overall evidence indicates that the primary thermal decompn. processes of these polysulfides yield cyclic sulfides or disulfides according to a backbiting process initiated at the SH ends. A .beta.-CH H transfer process occurring in parallel with the former produces compds. with both olefin and SH end-groups.


592) Fast atom bombardment mass spectrometry identification of oligomers contained in poly(.epsilon.-caprolactam) and poly(butylene isophthalate)

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Montaudo, A.Filippi, C.Guaita, P.Manaresi, F.Pilati

Macromolecules  20(5),  1029  - 1987

Cyclic and linear oligomers with mol. wts. .ltoreq.1450 of poly(.epsilon.-caprolactam) [25038-54-4] and poly(butylene isophthalate) [28087-45-8] were identified by fast-atom-bombardment mass spectrometry employing collision-activated decompn. ion scanning. Anal. of the oligomers by high-performance liq. chromatog. provided information only on compds. with mol. wts. .ltoreq.800.


593) Thermal decomposition processes in aromatic-aliphatic polyamides investigated by mass spectrometry

A.Ballistreri, D.Garozzo, P.Maravigna, G.Montaudo, M.Giuffrida

Journal of Polymer Science part A: Polymer Chemistry  25,  1049  - 1987

The thermal decompn. processes of some arom.-aliph. polyamides, derived from terephthalic acid and aliph. diamines, were studied by flash pyrolysis gas chromatog.-mass spectrometry and by direct pyrolysis-mass spectrometry, using both chem. ionization and electron impact modes. The primary thermal decompn. proceeded via a .beta.-CH hydrogen transfer process, with formation of pyrolysis products contg. amide and olefin end groups. Nitrile end groups were also formed by dehydration of the amide groups formed in the primary decompn. process.


594) Identification of pyrolysis products of polysulfides by collisionally activated decomposition linked scanning mass spectrometry

G.Montaudo, E.Scamporrino, C.Puglisi, D.Vitalini

Journal of Analytical and Applied Pyrolysis  10(4),  283  - 1987

Collisionally-activated decompn. (CAD) linked scan mass spectra were used in the identification of pyrolysis products obtained by the direct pyrolysis of some polysulfides in a mass spectrometer. Structures were detd. by comparing the CAD spectra of the pyrolysis products with those of authentic compds. The results were of help in elucidating the thermal degrdn. mechanisms that occur in the pyrolysis of the polysulfides investigated.


595) Analysis of polymers by mass spectrometry. Metastable mapping of transitions from pyrolysis products of an aromatic polyamide

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Montaudo

Journal of Analytical and Applied Pyrolysis  12(1),  3  - 1987

Metastable mapping was applied to the anal. of the mixt. of the pyrolysis products obtained from an arom. polyamide, pyrolyzed directly in a mass spectrometer. This technique permitted a rapid anal. of the components and provided a method for assigning structures through the study of mol. ions, characteristic fragmentations, and comparisons of daughter and parent ions of authentic samples. Collisionally activated decompn. spectra were obtained in order to induce a high intensity in the metastable transition. The thermal decompn. mechanism occurred via an intramol. exchange and a concomitant NH hydrogen transfer process with the formation of compds. with amine and/or succinimide end-groups.


596) Separation and characterization of cyclic sulfides formed in the polycondensation of dibromoalkanes with aromatic dithiols

G.Montaudo, E.Scamporrino, C.Puglisi, D.Vitalini

Journal of Polymer Science part A: Polymer Chemistry  25,  1653  - 1987

Mass-spectroscopy and gel. permeation chromatog. analyses were used to identify the cyclic oligomers formed in the polycondensation reactions of arom. dithiols and dibromoalkanes leading to arom.-aliph. polysulfides. A correlation existed between the 2 sets of data obtained by these techniques. Mass spectra of the cyclic oligomers formed in the polymn. reactions were reported.


597) Identification of the ions produced by fast atom bombardment mass spectrometry in some polyesters and polyamides

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Montaudo

Analytical Chemistry  59(17),  2024  - 1987

"Fast atom bombardment (FAB) mass spectrometry was applied to the anal. Of poly(ethylene adipate) poly(.epsilon.-caprolactone), nylon 66 and nylon 6. The peaks present in the spectra of the crude polymers were identified as corresponding to protonated mol. Ions of preformed cyclic oligomers and of low-mol.-wt. Compds. Contained in the polymer samples; these species were desorbed intact from the glycerol matrix under FAB conditions. When the polymer investigated were accurately purified from low-mol.-wt. Compds., no significant peaks were obsd. In their FAB mass spectra. Instead, the FAB mass spectra of the mixts. Extd. From the polymers were very similar to those obtained for crude polymers."


598) Mechanism of thermal generation of poly(p-phenylenevinylene) from poly(p-xylene-.alpha.-dimethylsulfonium halides)

G.Montaudo, D.Vitalini, R.W.Lenz

Polymer  28(5),  837  - 1987

The thermal conversion of poly(p-xylene-.alpha.-dimethylsulfonium halides) into poly(p-phenylenevinylene) (I) could occur through 2 concomitant reactions. The principal reaction was an elimination of Me2S and halogen acid, while the second reaction, an undesirable one, was the nucleophilic attack of the halide counterion on a Me group to form the Me halide and a Me sulfide. The 2 thermal processes were obsd. in the pyrolysis of both poly(p-xylene-.alpha.-dimethylsulfonium bromide) (II) and poly(p-xylene-.alpha.-dimethylsulfonium chloride). On storage at room temp., poly(p-xylene-.alpha.-dimethylsulfonium halides) underwent partial decompn. to I, as shown by thermogravimetric expts. The flash pyrolysis-gas chromatog.-mass spectrometry of I obtained by the thermal conversion of II at 400.degree. was also investigated.


599) Mechanism of thermal decomposition of nylon 66

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Montaudo

Macromolecules  20(12),  2991  - 1987

Thermal degrdn. of nylon 66 as studied by direct pyrolysis into the mass spectrometer proceeded via a C-H hydrogen-transfer reaction to nitrogen with formation of compds. contg. amine and ketoamide end groups. These primary degrdn. products further reacted or decompd. to form cyclopentanone, aminohexamethylene isocyanate, and compds. contg. amine and/or Schiff base groups.


600) Effect of N-methyl substitution on the thermal decomposition processes in aliphatic-aromatic polyamides

A.Ballistreri, D.Garozzo, G.Montaudo, M.Giuffrida

Journal of Polymer Science part A: Polymer Chemistry  25,  2351  - 1987

The thermal decompn. processes of two polyamides, derived from succinic acid and two arom. diamines, were studied by direct pyrolysis mass spectrometry. Fast-atom-bombardment mass spectrometry was also used to provide addnl. information for the elucidation of the thermal degrdn. mechanism of the polymers. The thermal stability of the N-methyl-substituted polyamide was higher than that of the unsubstituted polyamide. The difference in the thermal degrdn. mechanism accounted for the difference in the thermal stability of the two polyamides. The unsubstituted polyamide decompd. via an intramol. exchange and a concomitant N-H hydrogen transfer process with formation of compds. with amine and/or succinimide end groups. The N-methyl-substituted polyamide decompd. via an .alpha. C-H hydrogen transfer process from the Me group to the N atom with formation of compds. with amine and/or 2,5-piperidinedione end groups.


601) Thermal degradation of aromatic-aliphatic polyethers. 1. Direct pyrolysis-mass spectrometry

G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Macromolecules  19(3),  870  - 1986

The thermal degrdn. of 8 arom.-aliph. polyethers prepd. from dihydric phenols and aliph. or araliph. dihalides was studied by direct pyrolysis-mass spectrometry and thermogravimetry. The effect of ammonium polyphosphate was also examd. Polyethers prepd. from CH2Cl2 [75-09-2] underwent an intramol. exchange process, which produced cyclic compds., and a thermal rearrangement, producing compds. with aldehyde and Ph end groups. Polyethers from Cl(CH2)nCl (n = 2 or 6) decompd. mainly through a .beta.-CH hydrogen transfer to the O atom, producing compds. with hydroxy and olefin end groups. A thermal rearrangement leading to compds. with aldehyde and pentyl end groups was also active in polymers from Cl(CH2)6Cl. Polymers from p-xylylene dibromide (I) decompd. with extensive hydrogen-transfer reactions, leading to compds. with hydroxy and Me end groups, and through a .beta.-CH hydrogen transfer from the methylene to the Ph ring, generating compds. with aldehyde and Ph end groups. Ammonium polyphosphate lowered the thermal stability of all the polymers except those based on I. Ammonium polyphosphate sometimes changed the distribution of the pyrolytic compds. by inducing an acid-catalyzed thermal degrdn. of the polymer chain.


602) Thermal degradation of aromatic-aliphatic polyethers. 2. Flash pyrolysis-gas chromatography-mass spectrometry

G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Macromolecules  19(3),  882  - 1986

The flash pyrolysis-gas chromatog.-mass spectrometry (Py-GCMS) of two polyethers [p-C6H4(OH)2-CH2Cl2 copolymer [93975-21-4] and p-C6H4(OH)2-Cl(CH2)6Cl copolymer [26374-78-7]] and of a low-mol.-wt. model compd. (1,6-diphenoxyhexane [10125-18-5]) was performed. The pyrolysis products, generated through thermal rearrangement of polymer chains and subsequent thermal decompn. of thermal rearranged polymers, were identified also with the help of a mass spectra library search system. Among the pyrolysis products detected, aldehydes, phenols, ethers, and aliph. and arom. hydrocarbons were the most abundant. The Py-GCMS profile was characteristic of each sample analyzed, in the appearance of unique components and in the distribution of the pyrolysis products. The Py-GCMS results were compared with those obtained by direct pyrolysis-mass spectrometry of the same polyethers.


603) Correlation of thermal degradation mechanisms: polyacetylene and vinyl and vinylidene polymers

G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Journal of Polymer Science part A: Polymer Chemistry  24,  301  - 1986

The thermal degrdn. of poly(vinyl bromide) [25951-54-6], poly(vinyl chloride) [9002-86-2], poly(vinyl alc.) [9002-89-5], poly(vinyl acetate) [9003-20-7], poly(vinyl fluoride) [24981-14-4], poly(vinylidene chloride) [9002-85-1], and poly(vinylidene fluoride) [24937-79-9] was studied by direct pyrolysis-mass spectrometry and flash pyrolysis-gas chromatog.-mass spectrometry techniques. Vinyl and vinylidene polymers showed 2 competitive thermal degrdn. processes: (1) hydrogen halide elimination with formation of polyene sequences which underwent further mol. rearrangements, and (2) main-chain cleavage with formation of halogenated or oxygenated compds. The overall thermal degrdn. process depended on the prevailing decompn. reaction in each polymer, so different behaviors were obsd. The thermal degrdn. of polyacetylene [25067-58-7] was studied for the elucidation of the thermal decompn. mechanism of the vinyl and vinylidene polymers.


604) Direct mass spectrometry of polymers. XIV. Thermal fragmentation processes in poly-Schiff bases

A.Ballistreri, D.Garozzo, M.Giuffrida, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  24,  331  - 1986

The thermal fragmentation occurring in the title polymers is characterized by H transfer reactions. In the case of a totally arom. poly-Schiff base, the thermal fragmentation process involves H transfer from the methyne group with formation of fragments bearing nitrile and/or Ph end groups. In the case of arom.-aliph. poly-Schiff bases, H transfer occurs from the aliph. methylene groups. The latter process involves a lower energy and therefore occurs at lower temps. compared to the totally arom. polymer, with formation of thermal fragments bearing olefin and/or imine end groups. Beside these fragments, several thermal fragmentation compds. are also evolved by multiple H transfer reactions.


605) The role of intumescence on the flammability of vinyl and vinylidene polymers

G.Impallomeni, G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Journal of Applied Polymer Science  31(5),  1269  - 1986

Thermal stability and flammability properties of 6 structurally related vinyl and vinylidene polymers fail to show correlation. The combustion of these polymers is dominated by their char-forming ability. A remarkable intumescent effect is obsd. in poly(vinylidene chloride) [9002-85-1], poly(vinylidene fluoride) [24937-79-9] and PVC [9002-86-2] which accounts for the high flame extinguishment of these polymers.


606) Flame-resistant polycaproamide by anionic polymerization of .epsilon.-caprolactam in the presence of suitable flame-retardant agents

G.C.Alfonso, G.Costa, M.Pasolini, S.Russo, A.Ballistreri, G.Montaudo, C.Puglisi

Journal of Applied Polymer Science  31(5),  1373  - 1986

Poly(.epsilon.-caprolactam) [25038-54-4] with flame-retardant (FR) properties can be easily obtained by activated anionic polymn. of the monomer in the presence of adequate amts. of red P. Analogous results with reduced P content can be achieved by coupling red P with a synergistic compd. such as a chlorinated hydrocarbon or MgO. A peculiar advantage of this method is the possibility of obtaining a very fine and homogeneous dispersion of the FR additive in the polymer matrix, meanwhile avoiding the typical compounding techniques, which are expensive, often unsafe, and require melt mixing of the ingredients. Mol. thermal and mech. characterization, as well as morphol. of the resultant products, were detd.: no significant property changes were found when FR agents are present, apart from the improvement of the flame resistance.


607) Primary thermal decomposition processes in aliphatic polyesters investigated by chemical ionization mass spectrometry

D.Garozzo, M.Giuffrida, G.Montaudo

Macromolecules  19(6),  1643  - 1986

"The thermal decompn. Mechanisms of several polyesters (derived from aliph. Diols and dicarboxylic acids) and polylactones were studied by direct pyrolysis-mass spectrometry, using both pos. Chem. Ionization and neg. Chem. Ionization. The thermally formed compds. Were not stable under electron impact conditions. Instead, the results obtained by pos. And neg. Chem. Ionization indicated that intramol. Exchange reactions predominated in the primary thermal fragmentation processes, causing the formation of cyclic oligomers, which were particularly stable under chem. Ionization conditions. The only exception was poly-.beta.-propiolactone [24938-43-0]; in this case the thermal decompn. Mechanism involved .beta.-hydrogen transfer reactions."


608) Mixtures of cyclic oligomers of poly(lactic acid) analyzed by negative chemical ionization and thermospray mass spectrometry

D.Garozzo, M.Giuffrida, G.Montaudo

Polymer Bulletin  15(4),  353  - 1986

The distribution of the cyclic oligomers of poly(lactic acid) (I) formed both by pyrolysis of I and by equilibration with a catalyst was studied by the title method. The relative amts. of the oligomers present in the mixt. were also detd. by these methods.


609) Mass-spectrometric analysis of the thermal degradation products of poly(o-, m-, and p-phenylene sulfide) and of the oligomers produced in the synthesis of these polymers

G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Macromolecules  19(8),  2157  - 1986

Gel-permeation chromatog. and mass spectrometry were used to detect and identify the oligomers formed in the polymn. reactions leading to poly(o-phenylene sulfide) (I) [82860-14-8], poly(m-phenylene sulfide) (II) [32027-35-3], and poly(p-phenylene sulfide) (III) [25212-74-2]. The thermal degrdn. of I, II, and III was investigated by direct pyrolysis in the ion source of a mass spectrometer. I, II, and III decompd., producing the same kind of cyclic oligomers as obtained in polymn. The distribution of the pyrolysis products was different in the 3 cases and was dependent on the structure of each isomeric polymer.


610) Direct mass spectrometry of polymers

G.Montaudo

British Polymer Journal  18,  231  - 1986

A review with 44 refs. with emphasis on principles of the title method and exptl. aspects, applications, and comparison with other techniques.


611) Thermal decomposition mechanisms of sequential bipolyesters based on propene glycol and hydroxybenzoic/phthalic diacid derivatives.

M.Giuffrida, P.Maravigna, G.Montaudo, E.Chiellini

Journal of Polymer Science part A: Polymer Chemistry  24,  1643  - 1986

Direct pyrolysis-mass spectrometry of polyesters prepd. from propylene glycol and bis(4-carboxyphenyl) phthalate, isophthalate, or terephthalate showed that primary thermal fragmentation processes occur in which ester exchange reactions take place. The polyesters may undergo severe rearrangements in the thermal decompn. process, and compds. with structures different from those of the original polymer are formed.


612) Primary thermal fragmentation processes in poly(lactic acid) investigated by positive and negative chemical ionization mass spectrometry

D.Garozzo, G.Montaudo, M.Giuffrida

Polymer Degradation and Stability  15(2),  143  - 1986

The mechanism of thermal decompn. of poly(lactic acid) [104585-16-2] was studied by direct pyrolysis-mass spectrometry using electron impact (EI), pos. chem. ionization (CI) and neg. chem. ionization (NCI) methods. The thermally formed cyclic oligomers of lactic acid are not stable under EI conditions. The results obtained by CI and NCI indicate that intramol. exchange reactions predominate in the primary thermal fragmentation processes.


613) Thermal decomposition processes in aliphatic-aromatic polyamides investigated by mass spectrometry

A.Ballistreri, D.Garozzo, M.Giuffrida, P.Maravigna, G.Montaudo

Macromolecules  19(11),  2693  - 1986

The thermal decompn. processes of some polyamides derived from aliph. dicarboxylic acids and arom. diamines were studied by flash pyrolysis chromatog.-mass spectrometry and by direct pyrolysis-mass spectrometry, using both chem. ionization and electron impact modes. The thermal decompn. of these polyamides is strongly influenced by the structure of the aliph. dicarboxylic acid units. The formation of compds. with succinimide and amine end groups is obsd. in the pyrolysis of the polyamides contg. succinic units. In the pyrolysis of polyamides contg. adipic units, the primary thermal degrdn. products are compds. with amine and ketoamide end-groups. In the pyrolysis of the latter polyamides, secondary thermal fragments are also formed: cyclopentanone, CO2, and compds. with azomethine and isocyanate groups.


614) Separation and characterization of cyclic sulfides formed in the polycondensation of dibromoalkanes with aliphatic dithiols

G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Macromolecules  19(11),  2689  - 1986

Mass spectrometric and gel permeation chromatog. analyses are used to identify the cyclic oligomers formed in the polycondensation reactions of polymethylenedithiols with polymeththylene dibromides with the same no. of C atoms, leading to aliph. polysulfides. A correlation exists between the two sets of data obtained by these techniques. Cyclic oligomers with only an even no. of repeating units are detected among the polycondensation reaction products. This fact is considered evidence that these oligomers are generated directly from the reacting monomers and not by degrdn. of the corresponding polymers.


615) Comments on the paper "Thermal decomposition of poly(.gamma.-methyl L-glutamate)"

A.Ballistreri, M.Giuffrida, P.Maravigna, G.Montaudo

Macromolecules  19(12),  3011  - 1986

A polemic. The direct pyrolysis-mass spectrometric thermal decompn. (A) of poly(.gamma.-Me L-glutamate) [25086-16-2] was contrasted with the results of T. Kojima, T. Kurotu, and T. Kawaguchi (ibid. 1986, 19, 1281) who used a pyrolysis-gas chromatog.-mass spectrometric method which gave only secondary decompn. products. Method A provided diketopiperazines, which were primary decompn. products.


616) Thermal degradation processes of polyamides investigated by collision-activated decomposition mass spectrometry/mass spectrometry

A.Ballistreri, D.Garozzo, M.Giuffrida, G.Montaudo

Polymer Degradation and Stability  16(4),  337  - 1986

Linked scanning mass spectrometry was applied to the anal. of the mixt. of pyrolysis products obtained from some polyamides, pyrolyzed directly in a mass spectrometer. Collision-activated decompn. spectra were obtained in order to induce a higher intensity in the metastable transition. Linked scanning mass spectrometry provided a fast method for unambiguously assigning chem. structure through the study of mol. ions, characteristic fragmentations, and comparisons of daughter and parent ions of authentic samples.


617) Intumescent flame retardant for polymers. III. The polypropylene-ammonium polyphosphate-polyurethane system

G.Montaudo, E.Scamporrino, C.Puglisi, D.Vitalini

Journal of Applied Polymer Science  30(4),  1449  - 1985

The action of some mixts. of ammonium polyphosphate (I) and polyurethanes (II) as flame retardant agents for polypropylene (III) [9003-07-0] was examd. I-II systems behave as intumescent flame retardant formulations. The action of these systems is described by the comparison of the oxygen index values measured on molded pellets and on molded rods, by measurements of the polymer temp. just below the burning surface and by visual observations. A strong synergism between I and some II having piperazine units in the polymer chain was ascertained with a max. 3:1 ratio. The results also indicate that only polyurethanes with specific structure, in combination with I, are active as intumescent flame retardant agents on III combustion.


618) Direct mass spectrometry of polymers. XIII. Thermal fragmentation processes in copoly-.alpha.-amino acids

A.Ballistreri, M.Giuffrida, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  23,  1731  - 1985

The thermal fragmentation processes in proline-sarcosine and in proline-alanine copolymers were investigated by direct pyrolysis-mass spectrometry. Proline-sarcosine copolymers decomp. in three steps, yielding cyclic oligomers. The first step is characterized by the presence of the Sar-Sar, Sar-Pro, and Pro-Pro cyclic dimers. In the second step the formation of several series of cyclic oligomers up to nonamers-decamers can be obsd., while the third step of thermal decompn. process leads to the almost exclusive formation of Pro-Pro cyclic dimer. The proline-alanine copolymers show a single-step thermal degrdn. process leading to the formation both of cyclic oligomers and compds. with olefin and nitrile end-groups. The thermal decompn. of alanine units is affected by the neighboring units along the polymer chain. Sarcosine units act as thermally labile probes, causing the selective thermal cleavage of the pro-sar copolymer.


619) Direct mass spectrometry of polymers. XII. Thermal fragmentation processes in poly(.alpha.-amino acids)

A.Ballistreri, M.Giuffrida, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  23,  1145  - 1985

The thermal fragmentation processes in poly(.alpha.-amino acids) have been investigated by direct pyrolysis-mass spectrometry. The mass spectral data show that the pyrolytic breakdown of polyglycine [25718-94-9], polysarcosine [25951-24-0], and polyproline [25191-13-3] leads to the formation of cyclic oligomers. Polyalanine [25191-17-7], poly(phenylalanine) [25191-15-5], and polytyrosine [25619-78-7] decomp. yielding compds. with olefin and nitrile end-groups. Finally, in the case of poly(.gamma.-Me glutamic acid) [25086-16-2], the primary thermal process is the loss of MeOH with consequent formation, along the polymer chain, of pyroglutamic units, which yield cyclic dimer as main pyrolysis product.


620) Identification of polymers by library search of pyrolysis mass spectra and pattern recognition analysis

D.Garozzo, G.Montaudo

Journal of Analytical and Applied Pyrolysis  9(1),  1  - 1985

A library of mass spectra of polymers contg. .apprx.200 entries was described. These spectra were obtained by direct pyrolysis-electron-impact mass spectrometry, i.e., by heating the polymers in the direct insertion probe for solid samples at a const. heating rate and recording repetitive mass spectra during the temp. rise. The library could be used both as a data base for library searches and as a training set for a pattern recognition anal. The algorithm used to generate and search the files and a few applications of the library search and pattern recognition anal. were presented.


621) Mass spectral characterization and thermal decomposition mechanism of poly(dimethylsiloxane)

A.Ballistreri, D.Garozzo, G.Montaudo

Macromolecules  17(7),  1312  - 1984

The pyrolysis of di-Me siloxane was shown by mass spectrometry to form cyclic oligomers by intramol. exchange. The distribution of pyrolysis products was calcd. This distribution was not changed by the addn. of NaOH catalyst, although NaOH did lower the max. polymer decompn. temp. Cyclic oligomers present in di-Me siloxane from its prepn. could also be detected and identified by mass spectrometry.


622) Mechanism of thermal degradation of polyurethanes. Effect of ammonium polyphosphate

G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Macromolecules  17(8),  1605  - 1984

The thermal decompn. of some structurally related N-H and N-substituted polyurethanes and their mixts. with ammonium polyphosphate (I) was investigated by thermogravimetry and direct pyrolysis in a mass spectrometer. The N-H polyurethanes undergo a quant. depolymn. process with formation of compds. with amine and isocyanate end groups. The thermal degrdn. of the N-substituted polyurethanes proceeds by a different mechanism as a function of their chem. structure. Three thermal degrdn. pathways have been ascertained: N-H hydrogen transfer, .beta.-CH hydrogen transfer, and .alpha.-CH hydrogen transfer. The addn. of I lowers the thermal stability of N-substituted polyurethanes, whereas that of the other polymers remains unaltered. I often changes the nature of the pyrolytic products, sometimes inducing a hydrolytic cleavage of the polymer chain and sometimes causing the formation of tertiary amines.


623) Direct mass spectrometry of polymers. X. Primary thermal fragmentation processes in totally aromatic polyesters

S.Foti, M.Giuffrida, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  22,  1201  - 1984

The thermal decompn. of a series of isomeric poly(oxyphthaloyloxyphenylenes) and poly(m-hydroxybenzoic acid) (I) [25302-76-5] was studied by direct pyrolysis-mass spectrometry. Intramol. exchange reactions predominate in the primary thermal fragmentation processes, causing the formation of cyclic oligomers which are subsequently cleaved to open-chain fragments. The size and relative abundance of the cycles produced appear to be strongly influenced by steric factors, i.e., by the structure (para or meta) of the repeating unit in each polymer. In the case of I, the formation of cyclic oligomers contg. .ltoreq.7 repeating units is obsd.


624) Direct mass spectrometry of polymers. XI. Primary thermal fragmentation processes in aromatic-aliphatic polyesters

S.Foti, M.Giuffrida, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  22,  1217  - 1984

The thermal decompn. of 2 series of isomeric arom.-aliph. polyesters was studied by direct pyrolysis-mass spectrometry. Intramol. exchange reactions predominate in the primary thermal fragmentation processes to cause the formation of cyclic oligomers. Several secondary thermal processes may occur after the primary step: hydrolytic cleavage of the ester bond, decarboxylation, and .beta.-H transfer.


625) Mass spectral characterization and thermal decomposition mechanism of alternating silarylene-siloxane polymers

A.Ballistreri, G.Montaudo, R.W.Lenz

Macromolecules  17(9),  1848  - 1984

The thermal decompn. of two alternating silarylene-siloxane polymers was studied by direct pyrolysis into a mass spectrometer. Intramol. exchange reactions occurred during the primary thermal fragmentation processes causing the formation of cyclic compds. Only part of the thermal fragments had structures corresponding to the repeating unit of the polymers. The remaining pyrolytic products resulted from thermal rearrangement of the silarylene-siloxane polymer chain and had structures different from those of the original polymer repeating units. Both siloxane and p-phenylenedisilanol cyclic oligomers were found in the products.


626) Reliability of the volatilization method for determination of the activation energy in the thermal decomposition of polymers

A.Ballistreri, G.Montaudo, C.Puglisi

Journal of Thermal Analysis and Calorimetry  29,  237  - 1984

The linear programmed thermal degrdn. mass spectrometry method, used to det. kinetic parameters in the thermal degrdn. of polymers by means of volatilization curves, was applied to thermogravimetric data, and the results were compared with those obtained by the methods of J. H. Flynn and L. A. Wall (1966), H. L. Friedman (1965), E. S. Freeman and B. Carroll (1958), and A. W. Coats and J. P. Redfern (1964).


627) Mechanism of flame retardant action of red phosphorus in polyacrylonitrile

A.Ballistreri, G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini, S.Calgari

Journal of Polymer Science part A: Polymer Chemistry  21,  679  - 1983

The mechanism of the fire-retardant action of red P in polyacrylonitrile (I) [25014-41-9] combustion was investigated by thermogravimetry, flash-pyrolysis gas chromatog.-mass spectrometry, and combustion methods. Red P increased the thermal stability of I in air and induced a char-residue increment on I. Both of these effects disappeared when pyrolysis was performed under N flow. Flash pyrolysis gas chromatog.-mass spectrometry expts. showed that red P did not alter the pyrolysis product distribution of I, which implied that there was no specific interaction between I and red P. These data also showed that polymeric red P decompd. to volatile white P during pyrolysis. These observations allowed a proposal of a simple model for the mechanism of the fire-retardant action of red P on I at the mol. level. Combustion data for I-red P mixts. were in agreement with the proposed mechanism of the fire-retardant action.


628) Intumescent flame retardants for polymers. I. The poly(acrylonitrile)-ammonium polyphosphate-hexabromocyclododecane system

A.Ballistreri, G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Journal of Applied Polymer Science  28(5),  1743  - 1983

The influence of ammonium polyphosphate (I) and hexabromocyclododecane (II) [25637-99-4] as flame retardant on 92:8 (mol%) acrylonitrile-Me acrylate copolymer [24968-79-4] was examd. The I-II system behaves as an intumescent flame retardant formulation. I is the char-forming agent and II the blowing agent. A negligible gas-phase mode of action was ascertained for II with this substrate. A synergism between I and II was obsd., corresponding to about 50% increased efficacy with respect to the sep. effects of the 2 components. Thermogravimetry, O index, N2O index expts. and P residue measurements indicated that a condensed phase mechanism of action accounts for all the obsd. facts.


629) Direct mass spectrometry of polymers. IX. Copoly(carbonate-urethanes) prepared by reorganization of polycarbonates with piperazine

S.Foti, M.Giuffrida, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  21,  1599  - 1983

A detailed anal. of the reaction products generated by reorganization of polycarbonates [poly(isopropylidenediphenol carbonate) (Lexan 220) [24936-68-3] and poly(resorcinol carbonate) [32473-32-8]] with piperazine [110-85-0], performed by direct mass spectrometry methods, showed that this reaction actually followed the pathway postulated (V. Foldi and T. Campbell, 1962) and that, at 50% piperazine incorporation level, urethanediphenol compds. were almost exclusively produced. This afforded, on repolymn. with phosgene, alternating copoly(carbonate-urethanes) with thermal stabilities comparable to those of the parent polyurethanes. The primary fragmentation mechanisms in the thermal decompn. of these copolymers were studied by direct pyrolysis in the mass spectrometer. Ester exchange reactions predominated here, causing the formation of cyclic oligomers, which were subsequently cleaved to open-chain oligomers contg. hydroxy end groups.


630) Direct mass spectrometry of polymers. VIII. Primary thermal fragmentation processes in polyurethanes

S.Foti, M.Giuffrida, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  21,  1583  - 1983

The primary fragmentation mechanisms in the thermal decompn. of several polyurethanes [prepd. by reaction of bischloroformates of bisphenol A, resorcinol or hydroquinone with 4,4'-methylenebis(N-methylaniline), N,N'-dimethylhexamethylenediamine or piperazine] were studied by direct pyrolysis into the mass spectrometer. Ester exchange reactions predominate in the primary thermal fragmentation process causing formation of cyclic oligomers, which are subsequently cleaved to open-chain oligomers contg. hydroxyl end groups.


631) Direct mass spectrometry of polymers. VII. Primary thermal fragmentation processes in polycarbonates

S.Foti, M.Giuffrida, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  21,  1567  - 1983

The primary fragmentation mechanisms in the thermal decompn. of several polycarbonates [prepd. by interfacial polymn. of alk. solns. of bisphenol A, resorcinol or hydroquinone with bis(chloroformates) of 1,4-butanediol or COCl2] were studied by direct pyrolysis in the mass spectrometer. Ester exchange reactions predominate in the primary thermal fragmentation process, causing the formation of cyclic oligomers.


632) The effect of ammonium polyphosphate on the mechanism of thermal degradation of polyureas

G.Montaudo, E.Scamporrino, D.Vitalini

Journal of Polymer Science part A: Polymer Chemistry  21,  3321  - 1983

The thermal decompn. of structurally related N-H and N,N'-disubstituted polyureas and their mixts. with ammonium polyphosphate (APP) was investigated by thermogravimetry and direct pyrolysis in a mass spectrometer. The N-H polyureas undergo a quant. depolymn. process with the formation of oligomers with amine and isocyanate end groups. In contrast, the thermal degrdn. of the N,N'-disubstituted polyureas proceeds by a different mechanism as a function of their chem. structure. The addn. of APP lowers the thermal stability of the N,N'-disubstituted polyureas, whereas that of the N-H polyureas is unaltered. However, the data show that APP does not change the nature of the pyrolytic products. The destabilizing effect of the additive is attributed to the catalytic action of the acid species formed by its thermal decompn.


633) Intumescent flame retardants for polymers. II. The polypropylene-ammonium polyphosphate-polyurea system

G.Montaudo, E.Scamporrino, D.Vitalini

Journal of Polymer Science part A: Polymer Chemistry  21,  3361  - 1983

The mechanism of action was examd. of ammonium polyphosphate (I) and polyureas [poly(1-methylenetetrahydro-2-pyrimidinone) (II) [26968-79-6], poly(1,4-piperazinediylcarbonyl) (III) [32006-42-1], poly(iminocarbonylimino-1,4-phenylenemethylene-1,4-phenylene) [26099-74-1] and poly(iminocarbonylimino-1,4-phenylene) [88248-08-2]] as flame retardants for isotactic polypropylene (IV) [25085-53-4]. The I-polyurea system behaves as an intumescent flame-retardant formulation. Comparison of the O index measured on molded pellets and rods, values of the polymer temp. measured just below the burning surface, and visual considerations describe the intumescent flame retardant action of the system. A strong synergism between I and II or III was ascertained with a max. at 3:1 I-polyurea ratio. Thermogravimetric, O index, nitrous oxide index, and char-residue measurements were made. The data indicated that the polyurea acts as a catalyst for the charing reactions of I on IV.


634) Luminescence and photolytic cycloreversion of cyclobutane derivatives: cinnamic acid dimers and their diamides

G.G.Aloisi, U.Mazzucato, G.Bartocci, G.Cavicchio, P.Maravigna, G.Montaudo

Zeitschrift fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics  138,  207  - 1983

The fluorescence and photocycloreversion quantum yields for four cinnamic acid dimers and their diamides have been detd. in acetonitrile and methanol and their decay rate parameters estd. The results emphasize that the deactivation of the excited dimers occurs mainly through radiationless paths different from the photochem. cleavage reaction. The corresponding diamides have been also studied in water-methanol solns. at different pH. The trend of the fluorescence and photoreaction quantum yield as a function of pH gives information on the role of the acid-base equil. in the excited state on the photocleavage process.


635) Characterization of poly(carboxypiperazine) by mass analyzed ion kinetic energy spectrometry

S.Foti, A.Liguori, P.Maravigna, G.Montaudo

Analytical Chemistry  54(4),  674  - 1982

The identity of a key compd. in the mixt. of thermal oligomers originating in phosgene-piperazine copolymer [29796-90-5] pyrolysis was demonstrated by mass analyzed ion kinetic energy spectrometry. The mass spectral data show that the pyrolytic breakdown of this polyurea occurs through a single-stage decompn. mechanism that leads to CO and fragments with amino endgroups. The spectrometry application illustrates the potentialities of this technique in the anal. of mixts. obtained by direct pyrolysis of polymers in the mass spectrometer.


636) Mass spectrometric detection of cyclic oligomers in polyurethanes and polyureas

S.Foti, P.Maravigna, G.Montaudo

Macromolecules  15(3),  883  - 1982

The synthesis and characterization of cyclic urethane and urea oligomers formed from CH2(C6H4NMeCOCl-p), CH2(C6H4NHMe-p)2, CMe2(CH2O2CCl)2, COCl2, and HNMe(CH2)6NHMe leading to polyurethanes and polyureas are reported. Simultaneous detection and identification of these compds. directly from the polycondensation mixts. were achieved by mass spectrometry (MS). The cyclic oligomers, subsequent to detection by MS, were isolated by solvent extn. and characterized. Details of the MS method used are given, and its potential is discussed.


637) Mass spectral characterization of polymers. Primary thermal fragmentation processes in polyureas

S.Caruso, S.Foti, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  20,  1685  - 1982

The primary fragmentation processes in the thermal decompn. of a series of structurally related polyureas, in which N-hydrogens are partially or totally replaced by Me groups, were studied by direct pyrolysis with a mass spectrometer. Polyureas I (R = Me, R1 = H) [82837-41-0], II (R = H, R1 = Me) [82837-40-9], and I (R = R1 = H) [26099-74-1] undergo a quant. depolycondensation process analogous to that obsd. for N-monosubstituted polyurethanes. The thermal decompn. of polyureas II (R = R1 = Me) [81009-95-2], I (R = R1 = Me) [81009-94-1], and poly(1,4-piperazinediylcarbonyl) (III) [32006-42-1] proceeds by intramol. H transfer processes that occur at higher temps. with respect to the polycondensation. III is decompd. by a single-stage decompn. mechanism that leads to fragments with amino endgroups and CO.


638) Effects of N-methyl substitution on the thermal stability of polyurethanes and polyureas

S.Foti, P.Maravigna, G.Montaudo

Polymer Degradation and Stability  4(4),  287  - 1982

Thermogravimetric studies on a series of structurally related polyurethanes prepd. from diamines and bis(chloroformates) and polyureas prepd. from diamines and COCl2 are reported. The thermal stabilities of the N-methyl-substituted polymers are higher than those of the corresponding unsubstituted (N-H) polymers. Based on a knowledge of the primary thermal fragmentation processes in these polymers, an attempt was made to correlate chem. structure, mechanism of thermal decompn., and thermal stability.


639) Smoke suppression by ammonium polyphosphate in poly(acrylonitrile) combustion

A.Ballistreri, G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Journal of Applied Polymer Science  27(9),  3369  - 1982

The influence of ammonium polyphosphate (I) on the smoke emission of poly(acrylonitrile) (II) [25014-41-9] was examd., and its mechanism of action as a smoke suppressant agent was investigated. Smoke d. and corresponding residual char data, as a function of temp., were obtained in order to characterize the smoke propensity of II. The amt. of generated smoke, both in smoldering and flaming conditions, was considerably lowered by the presence of I, and higher char yields were obtained. A flame inhibiting effect of I on II was also shown. Thermogravimetry, O index, and N2O index expts. were also performed. I acts as a char-forming agent in II combustion. Both smoke suppression and flame inhibition effects are a consequence of this action.


640) Mechanism of thermal decomposition of poly(vinylidene chloride)

A.Ballistreri, S.Foti, P.Maravigna, G.Montaudo, E.Scamporrino

Polymer  22(1),  131  - 1981

The volatile decompn. products formed by heating poly(vinylidene chloride (I) [9002-85-1] were studied by mass spectroscopy. I tends to unzip to form the monomer when heated, but the unzipping rate is reduced by dehydrochlorination, leading to the formation of linear chlorinated polyenes which decomp. and rearrange intramol. to give arom. compds. This process occurs in parallel with crosslinking to yield a char. The volatilization rate profile of I contg. 10% ZnO showed that thermal decompn. occurred at a lower temp. than for pure I, with ZnCl2 appearing among the volatile pyrolysis products. The ZnCl2 catalyzed dehydrochlorination and lowered the rate of monomer evolution.


641) Mass spectrometric characterization and thermal decomposition mechanism of some poly(organophosphazenes)

A.Ballistreri, S.Foti, G.Montaudo, S.Lora, G.Pezzin

Die Makromoleculare Chemie  182,  1319  - 1981

Mass spectrometry of 1 polyaryloxyphosphazene and 4 polyaminophosphazenes is described. The spectra show that pyrolysis of poly[bis(.beta.-naphthyloxy)phosphazene] forms cyclic oligomers. Other poly[bis(arylamino)phosphazenes] decomp. at low temps. by a 2-stage process involving amine evolution. Pyrolysis of poly(dipiperidinophosphazene) leads to complete destruction of the polymer backbone, with formation of NH3 and elemental P. The wide range of pyrolysis mechanisms is unique to the phosphazene structure.


642) Mechanism of smoke suppression by metal oxides in PVC

A.Ballistreri, G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Journal of Polymer Science part A: Polymer Chemistry  19,  1397  - 1981

The amt. of smoke suppression induced in PVC [9002-86-2] by some metal oxides was measured as a function of temp. The amt. of CO2 evolved in the combustion was also measured simultaneously with smoke emission. In a smoldering condition, smoke occurred almost immediately, whereas CO2 occurred at a later stage. Both the smoke d. and the amt. of benzene suppression induced by metal oxides correlated well with the char yield. Crosslinking catalyzed by metal oxides is the principal mechanism of smoke inhibition and char oxidn. is responsible for the redn. of char yield.


643) Thermal decomposition of flame retardant acrylonitrile polymers. 2. Effect of red phosphorus

A.Ballistreri, S.Foti, G.Montaudo, E.Scamporrino, A.Arnesano, S.Calgari

Die Makromoleculare Chemie  182,  1301  - 1981

Red P was an efficient flame retardant for polyacrylonitrile (I) [25014-41-9] and, to a lesser extent, also for 64:36 acrylonitrile-vinylidene chloride copolymer (II) [9010-76-8]. Condensed-phase and gas-phase mechanisms are both responsible for the flame inhibition effect of red P on I, while a gas-phase mechanism seems to be responsible for the flame inhibition effect of red P on II. Flash-pyrolysis gas-chromatog. data, with products mass-spectral identification, are reported for I and II.


644) Smoke dilution methods for the evaluation of the smoke emission from burning polymers: a comparative approach

A.Ballistreri, G.Montaudo, C.Puglisi, E.Scamporrino, D.Vitalini

Fire and Materials  5(2),  61  - 1981

A combustion app. comprising a hot air quartz furnace that permits detn. of smoke emission of burning polymers over a wide range of parameters was used for the comparative approach to smoke emission. Smoke d. values were measured for polyacrylonitrile [25014-41-9], PVC [9002-86-2] and PVC contg. a no. of metal oxides. For PVC, the light intensity scattering from evolving smoke was measured as an alternative to smoke d.


645) Thermal degradation of polyurethanes. Model compounds. Comments

A.Ballistreri, S.Foti, P.Maravigna, G.Montaudo, E.Scamporrino

Journal of Applied Polymer Science  26,  2781  - 1981

A polemic. The failure of Orzeszko and Kolbrecki (ibid 1980, 25, 2969) to find phenyl isocyanate (I) [103-71-9] and ethylene glycol in the pyrolysis products of ethylene diphenylcarbamate [849-98-9] does not prove that the dissocn. of the urethane bond to the starting materials did not occur, since I would be hydrolyzed to aniline and CO2 which were found.


646) Mechanisms of thermal decomposition in totally aromatic polyurethanes

S.Foti, P.Maravigna, G.Montaudo

Journal of Polymer Science part A: Polymer Chemistry  19,  1679  - 1981

The primary fragmentation mechanisms in the thermal decompn. of polyurethanes, such as (NHZCH2ZNHCO2ZCMe2ZO2C)n (I) [31623-55-9], (NMeZCH2ZNMeCO2ZCMe2ZO2C)n (II) [80201-06-5], and (NMeZCH2ZNMeCO2CH2CMe2CH2O2C)n (III) [80201-07-6] with Z = p-C6H4) were studied by direct pyrolysis into the mass spectrometer. The remarkable difference in the thermal stability of I (m. 230-50.degree.) and II (m. 280-300.degree.) reflects their different decompn. pathways. I depolymerizes to give diisocyanate and diol as the primary fragments. II decomps. via the formation of the cyclic compd. (IV) [80192-36-5]. III decomps. with the formation of open-chain fragments.


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