Title: DEPENDENCE OF THE RADIATION SENSITIVITY OF E. COLI ON THE CULTURE METHOD AND ENVIRONMENTAL CONDITIONS AT THE TIME OF IRRADIATION BY X AND /cap alpha/-RAYS
Abstract: It was observed earlier that E. coli cultures in glucose possess different properties than the bacillus in its usual medium. The relative biological efiectiveness of these 2 types was investigated by exposing the 2 cultures to alpha radiation of Po/sup 210/ and to x radiation of various spectral composition, in an attempt to study the effect, if any, on the radiation sensitivity of the medium in which the irradiation was carried out. In the glucose type culture the dose curve obtained was S-shaped while the ordinary culture had an exponential shape. The S-shaped curve was also observed in the case of exposure to alpha -radiation. The radiation sensitivity of the glucose type culture was found to be lower by a factor of 4.5 for x radiation and a factor of 3 for alpha radiation than that of the ordinary culture. The relative biological effectiveness of the alpha radiation with respect to the 200-kev x radiation was 0.66 for the ordinary and 1.0 for the glucose culture. If intracellular toxic products play, an important role in the primary biological activity of the radiation, then the S-shape of the curve and the decreased radiation sensitivity of the cultures may be attributed tomore » the presence of antitoxic materials in the cells. (TTT)« less
Publication Year: 1963
Publication Date: 1963-01-01
Language: en
Type: article
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