X Irradiation of a Sensitive and a Resistant Strain of Escherichia Coli under Controlled Oxygen Concentrations.

van Soestbergen, A. A. (Brookhaven National Laboratory, Upton, N.Y.). X irradiation of a sensitive and a resistant strain of Escherichia coli under controlled oxygen concentrations. J. Bacteriol. 89:1032-1034. 1965.-Radiosensitive and radioresistant strains of Escherichia coli were given an X-ray dose of 4,544 rad at various controlled O(2) concentrations, and the results were subjected to probit analysis. A varkappa(2) test gave no evidence of heterogeneity of departure from fitted parallel probit lines obtained after plotting the probit of the surviving fractions of each of the two strains on the logarithm of the O(2) concentration. Under the conditions of the experiment, the ratio of the oxygen concentrations at which equal fractions of populations of E. coli B/r and E. coli B-s were killed by X irradiation was estimated to be about 4.4.