The effect of exogenous superoxide generator chemicals on sodA and flpA promoters expression in Lactococcus lactis
نویسنده
چکیده
Oxidative stress is caused by superoxide anion or hydrogen peroxide under aerobic growth condition. Some bacteria could eliminate toxic species of oxygen using S o d A enzyme. The effect of superoxide generating chemicals and hydrogen peroxide on sodA and f l p A promoter activities were investigated in this study. The observation indicated that the f l p A promoter activity increased with menadione addition in the f l p B mutant but not f l p A mutant backgrounds. Also s o d A activity increased 4-, 7-, 50, and 27-fold in shaking (250 rpm), memadione, paraquat and plumbagin addition respectfully. Catalase enzyme supplementation had positive effect on bacterial growth during exponential phase of f l p A mutants than f l p B mutants and wild type. Exogenously, hydrogen peroxide addition was unable to increase either s o d A promoter or S o d Aenzyme activity.
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Stress response in Lactococcus lactis: cloning, expression analysis, and mutation of the lactococcal superoxide dismutase gene.
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