Role of putrescine in the regulation of the expression of the oxidative stress defense genes of Escherichia coli

The role of putrescine in the adaptive response of Escherichia coli grown a erobically in synthetic M9 medium with glucose to the H2O2-induced oxidativ e stress was studied. Under oxidative stress, the expression of the single- copy reporter gene fusions oxyR'::lacZ and katG'::lacZ was found to undergo biphasic changes, which were most pronounced in glucose-starved E. coil ce lls. The concentration-dependent activating effect of putrescine on the exp ression of the OxyR regulon genes was maximum when the oxyR gene was inhibi ted by high concentrations of hydrogen peroxide.