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Role of secretion systems of Chromobacterium violaceum in the interaction with the host and other bacteria

Abstract

Gram-negative bacteria secrete proteins into the extracellular milieu or into host cells using protein devices called Type I to Type VI secretion systems or by releasing outer membrane vesicles (OMV). In this project, we propose to investigate the role of several of these secretion systems in the physiology and virulence of the opportunistic bacterium Chromobacterium violaceum. Studies have shown that the type III secretion system (T3SS) plays a role in the pathogenesis of this bacterium, but the other secretion systems have not yet been studied. Thus, we intend to study the type I (T1SS), type II (T2SS), and type VI (T6SS) secretion systems, as well as the OMVs of C. violaceum. Null mutant strains deficient in each of these nanomachines or with altered OMV biogenesis will be obtained and tested in mouse virulence and cell culture models. Gel-free quantitative proteomic analysis of the C. violaceum secretome comparing different mutant strains will be performed to identify which proteins are secreted by different secretion systems and by OMVs. It will be tested whether T1SSs and their secreted targets, RTX proteins, play a role in biofilm, adhesion, and cytotoxicity. We will investigate whether various extracellular degrading enzymes are targets secreted by T2SS. The role of T6SS in the interbacterial competition will be analyzed, as well as the degree of redundancy of the six C. violaceum T6SS VgrG paralog proteins. Gene expression analysis should reveal conditions that induce each machinery. The data obtained from this project will help to understand how different protein secretion systems contribute to the survival of C. violaceum in the environment and during its interaction with the host and competing bacteria. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
RODRIGUES DE SOUZA SANTOS, RENATO ELIAS; BATISTA, BIANCA BONTEMPI; DA SILVA NETO, JOSE FREIRE. Ferric Uptake Regulator Fur Coordinates Siderophore Production and Defense against Iron Toxicity and Oxidative Stress and Contributes to Virulence in Chromobacterium violaceum. Applied and Environmental Microbiology, v. 86, n. 21 NOV 2020. Web of Science Citations: 0.

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