Characterization of mucoid mutants of Escherichia coli K-12 isolated after exposure to ozone.

Seventy mucoid mutants retaining the phenotypic properties of the ultraviolet-induced lon strains of Escherichia coli K-12 were isolated after treatment of strain MQ259 (lon+) with ozone. They produce mucoid colonies at 37 C on minimal agar, are abnormally sensitive to radiation, and tend to grow in long aseptate filaments after irradiation with ultraviolet light. Results indicate also that ozone sensitivity, radiosensitivity, and mucoidy are pleiotropic properties of the lon gene.