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Iron homeostasis in Chromobacterium violaceum: regulatory mechanisms, uptake systems and role in virulence

Grant number: 18/01388-6
Support type:Regular Research Grants
Duration: July 01, 2018 - June 30, 2020
Field of knowledge:Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
Principal Investigator:José Freire da Silva Neto
Grantee:José Freire da Silva Neto
Home Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
Associated scholarship(s):19/20292-2 - Methods in molecular biology and microbiology as tools for study iron homeostasis in Chromobacterium violaceum, BP.TT


Iron is essential for most organisms but has low solubility and high toxicity in aerobic environments, in which life predominates. Bacteria have sophisticated mechanisms to maintain control of iron levels, whether in the environment or inside vertebrate hosts. In this work, we will investigate the role and regulation of candidate genes for systems of uptake, utilization, and regulation of iron homeostasis in Chromobacterium violaceum. As C. violaceum is a free-living bacterium found in soil and water that can cause serious infections in humans, the involvement of these systems in pathogenicity will also be investigated. The global identification of genes regulated by iron levels and by the transcription factor Fur will be performed through large-scale sequencing of RNA libraries (RNAseq). Target genes will be validated for expression and direct regulation by Fur. Regarding iron uptake systems, the endogenous siderophores produced by C. violaceum will be identified, and their pathways of synthesis and uptake by TonB-dependent receptors will be analyzed. Involvement of outer membrane vesicles (OMVs) in iron uptake will be investigated by proteome analysis of the OMVs under conditions of iron scarcity. Finally, the mutant strains obtained in the work will be used in virulence assays in mice. The results obtained in this project should reveal which strategies C. violaceum uses to obtain iron from the host and to avoid intoxication by this metal, besides contributing to the identification of the virulence determinants of this opportunistic bacterium. (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)
BATISTA, JULIANA H.; LEAL, FERNANDA C.; FUKUDA, TAISE T. H.; ALCOFORADO DINIZ, JULIANA; ALMEIDA, FAUSTO; PUPO, MONICA T.; DA SILVA NETO, JOSE F. Interplay between two quorum sensing-regulated pathways, violacein biosynthesis and VacJ/Yrb, dictates outer membrane vesicle biogenesis in Chromobacterium violaceum. ENVIRONMENTAL MICROBIOLOGY, v. 22, n. 6 MAY 2020. Web of Science Citations: 0.
BATISTA, BIANCA BONTEMPI; RODRIGUES DE SOUZA SANTOS, RENATO ELIAS; RICCI-AZEVEDO, RAFAEL; SILVA NETO, JOSE FREIRE. Production and Uptake of Distinct Endogenous Catecholate-Type Siderophores Are Required for Iron Acquisition and Virulence in Chromobacterium violaceum. Infection and Immunity, v. 87, n. 12 DEC 2019. Web of Science Citations: 0.
BARROSO, KELLY C. M.; PREVIATO-MELLO, MARISTELA; BATISTA, BIANCA B.; BATISTA, JULIANA H.; DA SILVA NETO, JOSE F. EmrR-Dependent Upregulation of the Efflux Pump EmrCAB Contributes to Antibiotic Resistance in Chromobacterium violaceum. FRONTIERS IN MICROBIOLOGY, v. 9, NOV 15 2018. Web of Science Citations: 3.

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