Impact of anti- oxidative gene mutation on dndogenous hydrogen peroxide regulation in Escherichia coli

To elucidate the synergy of anti- oxidative gene ( ahp C / F, kat E / G, oxyR ahp C / F, sod A / B) on endogenous hydrogen peroxide ( H2O2) regulation in Escherichia coli ( E.coli) .In this study, E.coli antioxidant gene mutants and wild type strain were used as the research object, ultraviolet spectrophotography was applicable for the assay of the hydrogen peroxide enzyme activity, fluorescence method was used to detect the endogenous H2O2 concentration, the quantity and localization of endogenous H2O2 were obtained by histochemical method, growth rule of the strains was determined by optical density. Results showed that compared with wild type strains, the hydrogen peroxide enzyme activity was overall elevated in the process of growth in mutant strains JI367, JI370 and AS240, H2O2 concentration in the whole growth cycle was reduced, but the results of the mutant strain LC74 was opposite.The results of histochemical staining showed that the accumulation of intracellular H2O2 in cell wall existed differences ( p < 0.05) , mutant strain LC74 had the most endogenous H2O2 cumulant, mutant strains JI367, JI370 and AS240 grew slowly, the growth speed of the mutant strain LC74 was faster than wild type in late logarithmic.Results showed that when the concentration of H2O2 accumulated to about more than 5.4μmol / L which would promote growth, the different antioxidant genes was regulated by OxyR and existed compensatory expression action, antioxidant enzymes Ahp C / F played a main role in the endogenous H2O2.This experiment provide a new evidence to bacteria regulatory mechanism of endogenous H2O2.