title: Cellular radiation effects and hyperthermia cell cycle kinetics of radiation sensitive mutants of Saccharomyces cerevisiae after X-irradiation and hyperthermia.
abstract: Radiosensitive mutants rad2, rad9, and rad51 of Saccharomyces cerevisiae were X-irradiated with 120 Gy or 60 Gy, heated at 50 degrees C for 30 min or treated with a combination of both and incubated in nutrient medium at 30 degrees C. Cell number, percentage of budding cells, and cell cycle progression were determined in 45-min intervals. Cell cycle kinetics were investigated by flow cytofluorometry. Hyperthermia leads mainly to a lengthening of G1, whereas X-rays arrest cells of the rad2 and rad9 mutant in G2 and the rad51--mutant additionaly in a state with DNA contents above G2. Cell division delay is influenced by oxygen in all strains but to a lesser extent in the rad2 mutant. The effect of the combined treatment appears to be merely additive in the rad2 and rad9 mutant while the rad51 mutant is sensitized to X-irradiation by hyperthermia. No selective action of hyperthermia on hypoxic cells was found.
mesh_terms: D002453:Cell Cycle / Q000528:radiation effects; D004271:DNA, Fungal / Q000528:radiation effects; D006358:Hot Temperature; D007700:Kinetics; D009154:Mutation; D011836:Radiation Tolerance; D012441:Saccharomyces cerevisiae / Q000528:radiation effects*
chemical_list: D004271:DNA, Fungal