[Isolation and characterization of E. coli B mutants sensitive or resistant to ozone]

Escherichia coli B strains, either more sensitive or resistant to ozone than wild-type (OZs or OZr), were obtained after mutagenesis. OZs strains carrying a mutation in ozrA or orzB, two genes located on both sides of malB, appeared as phenotypically different with regards to radiosensitivity and cellular filamentation. OZr strains, on the other hand, probably carry an allele of ozrA but were radioresistant and divided normally even with induction. A single gene (ozrA) thus seems to determine three levels of sensitivity to ozone, sensitivity to radiation and cellular filamentation in this organism. The possible involvement of a specific endonuclease in the repair of ozone-induced DNA lesions is considered.