Protein-l-isoaspartate (d-aspartate) O-methyltransferase (PCMT; EC 2.1.1.77) catalyses the methyl esterification of the free a-carboxyl group of abnormal l-isoaspartyl residues, which occur spontaneously in protein and peptide substrates as a consequence of molecular ageing. The biological function of this transmethylation reaction is related to the repair or degradation of age-damaged proteins. Methyl ester formation in erythrocyte membrane proteins has also been used as a marker reaction to tag these abnormal residues and to monitor their increase associated with erythrocyte ageing diseases, such as hereditary spherocytosis, or cell stress (thermal or osmotic) conditions.The study shows that levels of l-isoaspartyl residues rise in membrane proteins of human erythrocytes exposed to oxidative stress, induced by t-butyl hydroperoxide or H 2 O 2 . The increase in malondialdehyde content confirmed that the cell membrane is a primary target of oxidative alterations. A parallel rise in the methaemoglobin content indicates that proteins are heavily affected by the molecular alterations induced by oxidative treatments in erythrocytes. Antioxidants largely prevented the increase in membrane protein methylation, underscoring the specificity of the effect. Conversely, we found that PCMT activity, consistent with its repair function, remained remarkably stable under oxidative conditions, while damaged membrane protein substrates increased significantly. The latter include ankyrin, band 4.1 and 4.2, and the integral membrane protein band 3 (the anion exchanger). The main target was found to be particularly protein 4.1, a crucial element in the maintenance of membrane-cytoskeleton network stability. We conclude that the increased formation/ exposure of l-isoaspartyl residues is one of the major structural alterations occurring in erythrocyte membrane proteins as a result of an oxidative stress event. In the light of these and previous findings, the occurrence of isoaspartyl sites in membrane proteins as a key event in erythrocyte spleen conditioning and hemocatheresis is proposed.

The resistance of Helicobacter pylori strains to clarithromycin is increasing in several developed countries and their association with a genetic pattern circulation has been variously explained as related to different geographical areas. In this study we have reported: the prevalence of the resistance of H. pylori, isolated in Sicily, to clarithromycin; the principal point of mutation associated with this resistance; and the more frequent association between resistance to clarithromycin and cagA, the EPIYA motif, and the vacA and oipA genes. Resistance to clarithromycin was detected in 25 % of cases, the main genetic mutation involved being A2143G. The cagA gene was present in 48 % of cases and the distribution of the EPIYA motif was: ABC in 35 cases; ABCC in 8 cases; ABCCC in 2 cases; ABC-ABCC in 2 cases; and ABC-ABCC-ABCCC in 1 case. Regarding the vacA allele, an s1i1m1 combination was detected in 35 % of cases, s1i1m2 in 12 %, s1i2m2 in 12 %, s2i2m2 in 40 %, and a double s1m1-m2 mosaic in 1 % of cases. The status of the oipA gene was 'off' in 45 % of cases and 'on' in 55 %. Resistance to clarithromycin was found to be high in Sicily, but no correlation was found among resistance to clarithromycin, the vacA gene and oipA status; a higher correlation was observed between resistant strains and cagA-negative strains.

Cultural heritage constitutive materials can provide excellent substrates for microbial colonization, highly influenced by thermo-hygrometric parameters. In cultural heritage-related environments, a detrimental microbial load may be present both on manufacts surface and in the aerosol. In this study, bacterial and fungal colonisation has been investigated in three Sicilian confined environments (archive, cave and hypogea), each with peculiar structures and different thermo-hygrometric parameters. Particular attention has been paid to microorganisms able to induce artifacts biodeterioration and to release biological particles in the aerosol (spores, cellular debrides, toxins and allergens) potentially dangerous for the human health (visitors/users). Results provided information on the composition of the biological consortia, highlighting also the symbiotic relationships between micro (cyanobacteria, bacteria and fungi) and macro-organisms (plants, bryophyte and insects). The results of this integrated approach, including molecular biology techniques, are essential for a complete understanding of both microbial colonization of the cultural objects and the potential relationship with illness to human.

Plasma protein damage, as determined by protein L-isoaspartyl content, is increased in uremia. This alteration is to be ascribed to an increased protein structural instability, rather than the effect of hyperhomocysteinemia.

In recent decades research in the conservation and restoration field has provided sustainable alternatives to traditional procedures for cleaning or controlling the microbial colonization of works of art. In the present study, for the first time novel bioactive molecules extracted from marine invertebrate organisms (Anthozoa) were tested instead of chemical compounds for removing protein layers or as a biocide for controlling fungal or bacterial colonization. In particular, Bioactive Molecules with Protease activity (BMP), acting in a temperature range of 4-30°C, were tested for the hydrolysis of protein layers on laboratory specimens. The cleaning protocol provides a selective procedure to avoid damage to the original materials constituting the heritage object. Concurrently, enzymatic cleaning was also performed using commercial Protease from Aspergillus sojae (Type XIX), in order to compare their hydrolytic activities. Bioactive Molecules with Antimicrobial activity (BMA 1 , BMA 2 ) were tested to control bacterial (Bacillus, Micrococcus) or fungal (Aspergillus, Penicillium) growth, previously isolated from colonized canvas samples and characterized by an integrated approach based on in vitro culture, microscopy and molecular investigations. These molecules were tested to define the Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal/ Fungicidal Concentration (MBC/MFC). Specifically, BMAs were used to control fungal growth during the relining of the painting (laboratory specimens), carried out using a canvas support, and glue paste as binder. In our hypothesis, these molecules provide an important contribution to the development of innovative protocols for biocleaning or microbial growth control, based on fast and easy application, operator friendly and environmentally sustainable molecules.