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Heritable Glycogen-storage Deficiency in Yeast and its Induction by Ultra-violet Light
Abstract
SUMMARY: Cultures of several diploid strains of Saccharomyces cerevisiae were found to contain about 0.5% of glycogen-deficient cells. Ultraviolet irradiation increased the mutant frequency to about 5%, while 40% of the population survived. The mutants were detected by plating cultures on nutrient agar containing 1% glucose and staining 3-day colonies with iodine; normal colonies became brown due to the stored glycogen whereas the mutants remained white. The size of the mutant colonies was normal. Most of the mutants have remained stable during subculture. Fractionation of the cellular carbohydrate confirmed that the mutants were deficient in glycogen. Glucose concentration in the growth medium had a marked influence on glycogen storage. When the mutants were grown on nutrient agar containing 8% glucose, glycogen was stored and the mutants could not be distinguished by iodine-staining from the wild type. Glycogen-deficient mutants contained higher than usual proportions of respiration-deficient cells. Respiration-deficient colonies, whether derived from glycogen-deficient or from normal cultures contained appreciably less glycogen than those of the wild-type yeast.
- Accepted:
- Published Online:
© Society for General Microbiology 1968