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Aims: Staphylococcal biofilm-associated infections are resistant to conventional antibiotics. Consequently, new agents are needed to treat them. With this aim, we focused on the effector cells (coelomocytes) of the sea urchin Paracentrotus lividus immune system. Methods and Results: We tested the activity of the 5-kDa peptide fraction of the cytosol from coelomocytes (5-CC) against a group of Gram-positive, Gram-negative bacteria and fungi. We determined minimal inhibitory concentrations (MICs) ranging from 253·7 to 15·8 mg ml−1. We observed an inhibitory activity and antibiofilm properties of 5-CC against staphylococcal biofilms of reference strains Staphylococcus epidermidis DSM 3269 and Staphylococcus aureus ATCC 29213. The antimicrobial efficacy of 5-CC against the biofilms of clinical strain Staph. epidermidis 1457 was also tested using live/dead staining in combination with confocal laser scanning microscopy. At a sub-MIC concentration (31·7 mg ml−1) of 5-CC the formation of young (6-h old) and mature (24-h old) staphylococcal biofilms was inhibited. Conclusions: The biological activity of 5-CC could be attributed to three peptides belonging to the sequence segment 9–41 of a beta-thymosin of P. lividus. Significance and Impact of the Study: The effector cells of P. lividus represent an interesting source of marine invertebrates-derived antimicrobial agents in the development of new strategies to treat staphylococcal biofilms. [ABSTRACT FROM AUTHOR]

In this tutorial special feature, Dr Vincenzo Cunsolo and colleagues are introducing the readers to the characterization by MS‐based approaches of food‐derived proteins. Knowledge of protein composition is helpful for understanding the relationship between the protein content and the nutritional and technological properties of foodstuff, the production of methods for food traceability, the assessment of food quality and safety or even for the detection of genetically modified products and microbial contaminants. Moreover, considering that most of the more consumed foods (e.g. milk, eggs, cereals etc.) are responsible of allergenic reactions in humans, the detection of allergenic proteins represents a hot topic in the food safety field, because it may contribute to provide the basis for the production of hypoallergenics or to develop nutraceutical foods. Dr Cunsolo is a researcher of organic chemistry at the University of Catania. His research activity is mainly devoted to the structural characterization of food proteins, more specifically from kernel cereals and milk, by MS‐based proteomics methods. [ABSTRACT FROM AUTHOR]

Transglutaminase 2 (TG2 or TGM2) is a multi-functional enzyme which catalyzes transamidation reactions or acts as a G-protein in intracellular signalling. Tgm2-/-Mice lacking TG2 activity are glucose intolerant and show impairment of insulin secretion, suggesting an important physiological role for TG2 in the pancreatic β cell. We have previously described a TGM2 heterozygous missense mutation ((c.998A>G, p.N333S) in a 14 year-old patient with insulin-treated diabetes and in his diabetic father. The aim of this study was to further investigate the role of TG2 in early-onset type 2 diabetes. We analysed the TGM2 gene in 205 patients with clinically defined Maturity Onset Diabetes of the Young (MODY) or early-onset type 2 diabetes. We found two novel heterozygous mutations (c.989T>G, p.M330R; c.992T>A, p.I331N), which were not detected in 300 normoglycemic controls. All mutations were in residues which are located close to the catalytic site and impaired transamidating activity in vitro. Gene expression of TGM family genes and localization of TG2 in normal human pancreas indicated that TG2 is the only transglutaminase significantly expressed in human pancreatic islet cells. We conclude that reduced TG2 activity can contribute to disorders of glucose metabolism possibly via an impairment of insulin secretion. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]