Inducible repair of oxidative DNA damage in Escherichia coli

Hydrogen peroxide is lethal to many cell types, including the bacterium Escherichia coli^1,2. Peroxides yield transient radical species that can damage DNA³ and cause mutations⁴. Such partially reduced oxygen species are occasionally released during cellular respiration² and are generated by lethal and mutagenic ionizing radiation⁵. Because cells live in an environment where the threat of oxidative DNA damage is continual, cellular mechanisms may have evolved to avoid and repair this damage. Enzymes are known which evidently perform these functions^2,3. We report here that resistance to hydrogen peroxide toxicity can be induced in E. coli, that this novel induction is specific and occurs, in part, at the level of DNA repair.