Antioxidant defense by superoxide dismutases in Chromobacterium violaceum

• Grant number: 24/13883-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: José Freire da Silva Neto
• Grantee: Isabella Oliveira dos Santos
• 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

Superoxide dismutases (SODs) are antioxidant enzymes that catalyze the conversion of superoxide radicals into hydrogen peroxide and oxygen using metals as cofactors. Combating oxidative stress by SODs is an essential mechanism for life, as it prevents damage to macromolecules caused by the superoxide radical. Opportunistic pathogenic bacteria such as Chromobacterium violaceum are also exposed to oxidative stress generated by the host immune system. In this work, we propose to study the only two SODs of C. violaceum, both predicted to be from the iron/manganese family (Fe/Mn-SOD). The genes encoding these SODs, CV_2504 and CV_0867, will be deleted from the genome. The null mutants obtained will be characterized in vitro for growth profile and viability in the presence of oxidative stress and metals. The in-gel enzymatic activity of SODs will be evaluated in different cell fractions and in the presence of different metals to define their localizations and specificities. The data obtained in this study will clarify the relative importance of the two Fe/Mn-SODs for the survival of C. violaceum under oxidative stress.