Filament formation in radio-resistant mutants of Escherichia coli S after treatment with ultraviolet light and radiomimetic agents.

Curry, Janet (Stanford Research Institute, Menlo Park, Calif.) and Joseph Greenberg. Filament formation in radioresistant mutants of Escherichia coli S after treatment with ultraviolet light and radiomimetic agents. J. Bacteriol. 83:38-42. 1962.-The effect of ultraviolet light and of five radiomimetic compounds on cell division, growth in liquid medium, and growth in solid medium of Escherichia coli S and four of its radioresistant mutants was examined. All of the agents, including ultraviolet light, induced filaments in the parent S and in at least one of its radioresistant mutants; two of the agents, azaserine and mitomycin C, induced filaments in three of the mutants; in only one mutant were no filaments induced by any agent. Growth in solid medium was more sensitive to the agents than was growth in liquid medium. The mutants differed among each other in their degree of resistance to most of the chemical agents, when inhibition of growth in agar was used as the criterion. There was no difference among the mutants in the dose of any agent required to inhibit overnight growth in liquid medium.