Development of radiation resistance in Salmonella cultures.
Cultures of Salmonella subjected to repeated cycles of gamma-irradiation and subculture developed radiation resistance sooner at a low cycling dose ( approximately 1% survival) compared to a high cycling dose ( approximately 0.001% survival). Radioresistant cells in a population of radiosensitive cells of Salmonella newport or S. typhimurium could be selected by the double-irradiation plate method. The frequency of radioresistant cells in a population of S. newport was found to be about 1 per 8.9 million. Radio-resistant cells obtained by cyclic irradiation and subculture were larger (plumper) than the parent strain and showed a marked pleomorphism.
D008722:Methods; D008854:Microscopy, Electron; D009154:Mutation; D011830:Radiation Effects; D011831:Radiation Genetics; D012475:Salmonella / Q000528:radiation effects*; D012641:Selection, Genetic