title: Important role of catalase in the cellular response of the budding yeast Saccharomyces cerevisiae exposed to ionizing radiation.
abstract: Ionizing radiation indirectly causes oxidative stress in cells via reactive oxygen species (ROS), such as hydroxyl radicals (OH(-)) generated by the radiolysis of water. We investigated how the catalase function was affected by ionizing radiation and analyzed the phenotype of mutants with a disrupted catalase gene in Saccharomyces cerevisiae exposed to radiation. The wild-type yeast strain and isogenic mutants with disrupted catalase genes were exposed to various doses of (60)Co gamma-rays. There was no difference between the wild-type strain and the cta1 disruption mutant following exposure to gamma-ray irradiation. In contrast, there was a significant decrease in the ctt1 disruption mutant, suggesting that this strain exhibited decreased survival on gamma-ray exposure compared with other strains. In all three strains, stationary phase cells were more tolerant to the exposure of gamma-rays than exponential phase cells, whereas the catalase activity in the wild-type strain and cta1 disruption mutant was higher in the stationary phase than in the exponential phase. These data suggest a correlation between catalase activity and survival following gamma-ray exposure. However, this correlation was not clear in the ctt1 disruption mutant, suggesting that other factors are involved in the tolerance to ROS induced by irradiation.
authors.affiliation: Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan.
authors.forename: Takuto
authors.initials: T
authors.lastname: Nishimoto
authors.forename: Masakazu
authors.initials: M
authors.lastname: Furuta
authors.forename: Michihiko
authors.initials: M
authors.lastname: Kataoka
authors.forename: Masao
authors.initials: M
authors.lastname: Kishida
mesh_terms: D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D004789:Enzyme Activation; D005720:Gamma Rays; D015870:Gene Expression; D050296:Microbial Viability / Q000235:genetics / Q000528:radiation effects; D009154:Mutation; D011839:Radiation, Ionizing; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*
chemical_list: D002374:Catalase