Increase in the Intracellular Hydrogen Peroxide Concentration in Escherichia coil Cells Treated with Ethanol and Its Relation to Cell Death

抄録

When Escherichia coil cells were treated with 20-40% (v/v) ethanol solution, there was an increase in intracellular concentration of hydrogen peroxide accompanied by a decrease in the survival rate of the cells. Several mutants with higher catalase activity were more resistant and some other mutants with lower catalase activity were more sensitive to ethanol treatment than the parent strain K12. The concentration of hydrogen peroxide in the ethanol-treated E. coil K12 cells was 20 to160 times higher than that in the untreated cells. The catalase-gene kat E', kat G, and kat E cloned strains, having higher catalase activity, were more ethanol-resistant than E. coil K12, recipient strain UM1 and UM1 charomid 9-28. For the bactericidal mechanism of ethanol, it is suggested that ethanol treatment might cause some damage to the cellular aerobic respiratory system and as a result, hydrogen peroxide may be generated to result in cell death.