ACTIVITY OF THE ESCHERICHIA-COLI MUTT MUTATOR ALLELE IN AN ANAEROBIC ENVIRONMENT

Mutation frequencies For an Escherichia coli mutT strain were measured in both aerobic and anaerobic environments. When cells were grown in a rich medium (L broth), mutation frequencies were similar in both aer obic and anaerobic conditions. In contrast, when groan in a minimal me dium, mutT anaerobic mutation frequencies were reduced dramatically co mpared with aerobic values, which were similar to L broth frequencies. L broth mutT cultures treated with a commercial enzyme complex that r educes free oxygen in the medium also showed strongly reduced anaerobi c mutation frequencies. These results indicate that the biological rol e of the MutT protein is to prevent oxidative damage from becoming mut agenic.