title: Ethidium bromide mutagenesis in yeast: protection by anaerobiosis.
abstract: The mutagenesis by ethidium bromide, an intercalating dye, which induces the mutation from wild type (rho+) to the cytoplasmic respiratory deficient petite (rho-) in Saccharomyces cerevisiae, was studied under aerobic and anaerobic conditions. During growth of anaerobic cells at pH 6.5, ethidium bromide at a concentration of 2 mug/ml is unable to induce rho- mutants whereas under aerobic conditions the entire population is converted into rho- cells within 1 generation at the same drug concentration. With ethidium bromide 10 mug/ml 98% of the anaerobic cells are transformed into rho- in 5.5 h (more than 2 generations). In non-growing conditions, ethidium bromide 10 mug/ml has no effect in anaerobic cells. 3 h adapted cells used as control, are converted into rho- in 8 h. Increasing the ethidium bromide concentration to 20 mug/ml resulted in the appearance of some rho- mutants in the anaerobic population but marked at the same time the onset of a detectable toxic effect of the drug.
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D003513:Cycloheximide / Q000494:pharmacology; D004996:Ethidium / Q000494:pharmacology*; D008660:Metabolism; D009153:Mutagens; D012441:Saccharomyces cerevisiae / Q000502:physiology*
chemical_list: D009153:Mutagens; D003513:Cycloheximide; D004996:Ethidium