Glutathione and antioxidant defense in the bacterium Chromobacterium violaceum

• Grant number: 25/25440-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2026
• End date: December 31, 2026
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: José Freire da Silva Neto
• Grantee: Sidney Silva Amorim
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 21/06894-0 - Bacterial transcription factors involved in metal homeostasis, oxidative stress and virulence: investigating how Chromobacterium violaceum switches from the environment to the host, AP.JP2

Abstract

Antioxidant defense mechanisms are fundamental in all living organisms. Bacteria have varied arsenals of enzymes and small antioxidant molecules such as glutathione to combat endogenous oxidants and those from external sources, such as reactive oxygen species generated by host immune cells. In this project, we will investigate the role of glutathione in Chromobacterium violaceum, an environmental bacterium that occasionally causes serious infections in humans. Previously, mutant strains incapable of synthesizing glutathione were generated by deleting the gshA and gshB genes from the C. violaceum chromosome. The mutants were also preliminarily tested for susceptibility to oxidizing agents and metals in growth curve assays. These assays will be repeated with other agents to assess whether glutathione protects C. violaceum from toxicity by metals and oxidants. The expression of the gshAB genes will be evaluated in the presence of these same compounds. We will also investigate the role of gshAB in the virulence and motility of C. violaceum. The project data will contribute to understanding the role of glutathione in bacterial pathogenesis and defense strategies against oxidizing agents. (AU)