Modification of the Biological Effects of Ultraviolet Irradiation by Post-irradiation Treatment with Iodoacetate and Peptone: With an appendix on an interpretation of the effects of post-irradiation treatments based on a chemical model

Abstract

SUMMARY: A study has been made of the effects of post-irradiation treatment of ultraviolet irradiated spores of Streptomyces sp. strain T12 with distilled water, iodoacetate and a peptone medium. At doses exceeding 400 ergs/mm.2 (which exceed that corresponding to the peak of the dose/variant-frequency curve) treatment in distilled water results in increases in both the proportion of survivors and the frequency of variants amongst the survivors. Treatment with iodoacetate caused larger increases, whereas treatment with peptone medium suppressed the increases. A partial resolution of the lethal and mutagenic effects of the radiation was obtained at lower doses, for it was possible to modify the proportion of survivors without changing the variant frequency.