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Humans are estimated to consume several grams per week of nanoplastics (NPs) through exposure to a variety of contamination sources. Nonetheless, the effects of these polymeric particles on living systems are still mostly unknown. Here, by means of CD, NMR and TEM analyses, we describe at an atomic resolution the interaction of ubiquitin with polystyrene NPs (PS-NPs), showing how a hard protein corona is formed. Moreover, we report that in human HeLa cells exposure to PS-NPs leads to a sensible reduction of ubiquitination. Our study overall indicates that PS-NPs cause significant structural effects on ubiquitin, thereby influencing one of the key metabolic processes at the base of cell viability.

Membrane fusion/fission is a highly dynamic and conserved process that responds to intra- and extracellular signals. Whereas the molecular machineries involved in membrane fusion/fission have been dissected, regulation of membrane dynamics remains poorly understood. The lysosomal vacuole of budding yeast (Saccharomyces cerevisiae) has served as a seminal model in studies of membrane dynamics. We have previously established that yeast ENV7 encodes an ortholog of STK16-related kinases that localizes to the vacuolar membrane and downregulates vacuolar membrane fusion. Additionally, we have previously reported that Env7 phosphorylation in vivo depends on YCK3, a gene that encodes a vacuolar membrane casein kinase I (CKI) homolog that nonredundantly functions in fusion regulation. Here, we report that Env7 physically interacts with and is directly phosphorylated by Yck3. We also establish that Env7 vacuole fusion/fission regulation and vacuolar localization are mediated through its Yck3-dependent phosphorylation. Through extensive site-directed mutagenesis, we map phosphorylation to the Env7 C terminus and confirm that Ser-331 is a primary and preferred phosphorylation site. Phospho-deficient Env7 mutants were defective in negative regulation of membrane fusion, increasing the number of prominent vacuoles, whereas a phosphomimetic substitution at Ser-331 increased the number of fragmented vacuoles. Bioinformatics approaches confirmed that Env7 Ser-331 is within a motif that is highly conserved in STK16-related kinases and that it also anchors an SXXS CKI phosphorylation motif ((328)SRFS(331)). This study represents the first report on the regulatory mechanism of an STK16-related kinase. It also points to regulation of vacuolar membrane dynamics via a novel Yck3–Env7 kinase cascade.

The influence of crystal polymorphism on the thermal properties of poly( l -lactic acid) (PLLA) is discussed in this contribution. Crystallization of PLLA at high temperatures yields the stable α form, whereas at low temperatures the metastable α′ modification develops, which is characterized by slightly larger lattice dimensions compared to the α counterpart, and by some degree of conformational disorder. Quantitative analysis with conventional and temperature-modulated calorimetry revealed a three-phase structure of PLLA composed of a crystal phase and two amorphous fractions with different mobility, for all the analyzed thermal histories. A higher coupling of the amorphous chain segments with the crystal phase was found in the presence of α crystals, probably due to the slightly larger lattice dimensions and the looser arrangements of PLLA chains in the α′ structure. Some peculiarities in the thermal behavior were rationalized, like an unusual frequency-dependence of the reversing apparent heat capacity upon the solid–solid transition from the α′ to the α crystals. Devitrification of the rigid amorphous segments seems also to be differently affected by the coupled crystal structure for the two analyzed crystal modifications of PLLA.

Membrane fusion depends on conserved components and is responsible for organelle biogenesis and vesicular trafficking. Yeast vacuoles are dynamic structures analogous to mammalian lysosomes. We report here that yeast Env7 is a novel palmitoylated protein kinase ortholog that negatively regulates vacuolar membrane fusion. Microscopic and biochemical studies confirmed the localization of tagged Env7 at the vacuolar membrane and implicated membrane association via the palmitoylation of its N-terminal Cys13 to -15. In vitro kinase assays established Env7 as a protein kinase. Site-directed mutagenesis of the Env7 alanine-proline-glutamic acid (APE) motif Glu269 to alanine results in an unstable kinase-dead allele that is stabilized and redistributed to the detergent-resistant fraction by interruption of the proteasome system in vivo. Palmitoylation-deficient Env7C13-15S is also kinase dead and mislocalizes to the cytoplasm. Microscopy studies established that env7Δ is defective in maintaining fragmented vacuoles during hyperosmotic response and in buds. ENV7 function is not redundant with a similar role of vacuolar membrane kinase Yck3, as the two do not share a substrate, and ENV7 is not a suppressor of yck3Δ. Bayesian phylogenetic analyses strongly support ENV7 as an ortholog of the gene encoding human STK16, a Golgi apparatus protein kinase with undefined function. We propose that Env7 function in fusion/fission dynamics may be conserved within the endomembrane system.

With the aim at formulating new materials with biocidal activity a silver/polyurethane nanocomposite was prepared by in situ reduction of silver nitrate in a solution consisting of a commercial poly(carbonate urethane) dissolved in DMF, DMF acting as both polymer solvent and reducing agent. Bacteriological tests were performed with mesophilic, Gram-positive and Gram-negative bacteria, in liquid media and on solid agar plates supplemented with nanocomposite film samples. The growth inhibition achieved proved that the material set up was an effective bactericide. Release tests against E. coil were also carried out showing that the silver/polyurethane achieved exerts its biocidal activity through slow release of silver nanoparticles. Two different mechanisms reported in literature were invoked to account for the biocidal action of the silver nanoparticles released.

Two different diisocyanates were investigated as co-monomers for in situ polymerisation of poly(urethane-urea) into Neapolitan yellow tuff for conservation and restoration purpose. The obtained copolymers were characterised by means of FTIR spectroscopy, whereas the protective and consolidating efficiency of the performed treatments was evaluated through water capillary absorption, water vapour permeability and abrasion resistance measurements. The distribution and the penetration depth of the synthesized copolymer were also analysed applying micro-FTIR. The morphology of treated tuff was investigated by SEM. It was shown that comparatively higher protective and consolidating properties are achieved by using 1,6-diisocyanatohexane as monomer for in situ polymerisation.

5132 Background: In a previous study (Marinaccio et al. Proc.ASCO 2003;Abstr1952) we assumed that pretreatment normalization of mild anemia with epoetin alfa could improve the outcome in patients with epithelial ovarian cancer. The aim of this larger trial was to understand better the influence of recombinant human erythropoietin (rHuEPO) on the outcome of ovarian cancer patients showing anemia before undergoing surgery and chemotherapy. Methods: Between 1999 and 2003, 42 patients with mild anemia (Hgb 10.6–11.9 g/dL) secondary to advanced epithelial ovarian cancer were randomized to receive epoetin alfa (21 pts.) or not (21 pts.) before primary surgery. All patients were without past or present second malignancy and aged less than 76 years. FIGO stage at diagnosis was as follows: IC 13/42; II 5/42; III 19/42; IV 5/42. After surgery all patients underwent adjuvant chemotherapy with paclitaxel (175mg/mq) plus carboplatin (AUC5). Patients in the treatment group were administered rHuEPO, 10.000 IU, three tim...