Question

What are reactive oxygen apecies and how are they produced?

Answer 1

Inactivation of Reactive Oxygen Species

Reactive oxygen species damage DNA and inhibit bacterial oxidative phosphorylation. Bacteria may escape from the damaging effect of reactive oxygen species by rapid detoxification of the bactericidal products and by efficient DNA repair. Several bacterial pathogens produce superoxide dismutase (SOD) and catalase, two enzymes that degrade reactive oxygen species. Bacteria also express Rec-A enzymes to repair damaged DNA. In Salmonellae, the RecA pathway is critical, as recA mutants are avirulent. The ability of S. enterica to modify the endocytic pathway of the host cell seems to be the most important mechanism of resistance to reactive oxygen species. In macrophages, virulent Salmonellae localize in phagosomes devoid of NADPH oxidase, the enzyme that drives the respiratory burst.73