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


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)

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Scientific publications (6)
(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)
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, . (13/25745-9, 15/12605-0, 12/20435-9, 18/01388-6)
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, . (18/01388-6, 18/25445-9, 13/50954-0, 15/26349-5)
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, . (18/01388-6, 12/20435-9, 17/03342-0, 17/02998-0)
DE LIMA, VINICIUS M.; BATISTA, BIANCA B.; DA SILVA NETO, JOSE F.. The Regulatory Protein ChuP Connects Heme and Siderophore-Mediated Iron Acquisition Systems Required for Chromobacterium violaceum Virulence. FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY, v. 12, p. 15-pg., . (18/19058-2, 20/00259-8, 18/17716-2, 18/01388-6)
SANTOS, RENATO E. R. S.; DA SILVA JUNIOR, WALDIR P.; HARRISON, SIMONE; SKAAR, ERIC P.; CHAZIN, WALTER J.; DA SILVA NETO, JOSE F.. The Zinc Transporter ZnuABC Is Critical for the Virulence of Chromobacterium violaceum and Contributes to Diverse Zinc-Dependent Physiological Processes. Infection and Immunity, v. 89, n. 11, . (17/03342-0, 20/00259-8, 18/01388-6, 18/14737-9)
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, . (17/03342-0, 18/01388-6, 20/00259-8, 18/19058-2)

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