ANALYSIS OF A GENE CONTROLLING CELL DIVISION AND SENSITIVITY TO RADIATION IN ESCHERICHIA COLI.

Adler, Howard I. (Oak Ridge National Laboratory, Oak Ridge, Tenn.), and Alice A. Hardigree. Analysis of a genetic locus controlling cell division and sensitivity to radiation in Escherichia coli. J. Bacteriol. 87:720-726. 1964.-Radiation sensitivity in Escherichia coli is under control of genes that are transferred during conjugation between donor and recipient strains. Conjugation experiments establish that one of these genes occupies a locus on the E. coli K-12 linkage map between the genes controlling ability to utilize lactose and galactose. It affects sensitivity to both ionizing and ultraviolet (2,537 A) radiation. A strain possessing a mutation at this locus fails to show increases in resistance to ionizing radiation during late lag and early log phases, and increases in resistance when grown to stationary phase in a glucose-containing complete medium. The primary effect of the mutation at this locus may be an interference with the mechanism by which cells form cross plates. Cells of the mutant form long, nonseptate filaments when grown after exposure to ionizing radiation. The filaments do not give rise to macrocolonies. Pantoyl lactone, an agent that initiates cross plate formation, allows the filaments to divide normally and produce macrocolonies. When plated after irradiation on complete medium containing pantoyl lactone, the survival of the mutant is greatly increased.