ISOLEMENT ET CHARACTÉRISATION DE MUTANTS SENSIBLES OU RÉSISTANTS À L'OZONE CHEZESCHERICHIA COLIB

Abstract

Escherichia coli B strains, either more sensitive or resistant to ozone than wild-type (OZsor OZr), were obtained after mutagenesis. OZsstrains carrying a mutation in ozrA or orzB, two genes located on both sides of malB, appeared as phenotypically different with regards to radio-sensitivity and cellular filamentation. OZrstrains, 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.