ANALISI PROTEOMICA DI SURNATANTI BATTERICI AVENTI AZIONE BENEFICA PER LA SALUTE UMANA

A new era in medical science has dawned with the realization of the critical role of the ¿forgotten organ,¿ the gut microbiota, in health and disease. The advent of high-throughput methodologies and the elaboration of sophisticated analytic systems have facilitated the detailed description of the composition of the microbial constituents of the human gut, as never before. These discoveries also open the way for the development of therapeutic strategies that might modify the microbiota, for example through the use of probiotics, defined as 'live micro-organisms which, when administered in adequate amounts as part of food, confer a health benefit on the host', as proposed by the Joint FAO/WHO Expert Consultation in 2001. In the research of the molecular biology of probiotic bacteria, one worthy technique is proteomics. The spectrum of extracellular proteins, the secretome, has been studied in a few potentially probiotic lactobacilli and bifidobacterial. These proteins are potential candidates for understanding the interaction between probiotic bacteria and the human host. The study of extracellular proteins may provide novel strategies for the clinical application of probiotic bacteria and may allow understanding of their mechanism of action. In this thesis, proteins secreted by a probiotic strain: L. rhamnosus GG and by two potential probiotic strains isolated from table olives: L. pentosus S3T60C and of L. plantarum S11T3E, grown in MRS, have been identified. Particular interest will be addressed towards proteins potentially implicated in adhesion to gut mucosa, a key requirement for exerting beneficial effects since it prolongs the persistence of the probiotic in the intestine, as well as towards proteins having immunomodulatory and antitumor action.