IX. Nucleinsäuregehalt und Nucleinsäuresynthese nach Röntgenbestrahlung

Open Access
Publisher Website
Google Scholar
Abstract
The amount of DNA and RNA per dry weight as well as the rate of RNA synthesis was determined in a series of almost isogenic and homozygous Saccharomyces strains of different ploidy which had irradiated with different doses of X-rays. It was found that the RNA content per dry weight showed only a small decrease after irradiation even with high doses. The decrease in the DNA content after irradiation is larger, and it is already maximal at the smallest X-ray dose tested (75 krad) . No further decrease could be observed even after application of 225 krad. The RNA synthesis is much more radioresistant in all strains tested (haploid-hexaploid) than the colony forming ability. X-ray doses which reduce the colony forming ability of the cells to less than 1% lead to a reduction of the RNA synthesis of only about 50 per cent. The inactivation of RNA synthesis increases with increasing irradiation doses and increasing incubation time after irradiation. There was only a small difference in the radiosensitivity of the synthesis of soluble or ribosomal RNA. Genetic effects on the radiation inactivation of the colony forming ability, previously described as “aα-effect” and “AS-effect”, show no influence on the radiosensitivity of cellular nucleic acid content and synthesis.