SULPHUR NUTRITION OF TWO STRAINS OF THE YEAST, DEBARYOMYCES KLOECKERI, ISOLATED FROM SUBANTARCTIC SOIL

• Published in: Canadian Journal of Microbiology
• Main Authors: Skerman, T. M., Singleton, R. J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1964
• Subjects: Genetics; Molecular Biology; Applied Microbiology and Biotechnology; General Medicine; Immunology; Microbiology; Macquarie Island
• Online Access: http://dx.doi.org/10.1139/m64-053; http://www.nrcresearchpress.com/doi/pdf/10.1139/m64-053

A Debaryomyces kloeckeri strain from a Macquarie Island soil proved to be parathiotrophic, unable to satisfy its sulphur requirements from inorganic sources; certain sulphur amino acids were necessary. By contrast, inorganic sulphate and thiosulphate, but not dithionate, sulphide, or colloidal sulphur, were effective sulphur sources for a second (euthiotrophic) strain.Both strains behaved identically towards various organic sulphur compounds tested as sole sulphur sources. Growth was supported by L-cysteine, L-cystine, DL-homocysteine, DL-cystathionine, L-cystathionine, DL-lanthionine, D- and L-methionine, methionine sulphoxide, methyl DL-methionine sulphonium chloride, and thiazolidine-4-carboxylic acid. Ineffective were methanethiol, thioglycollate, reduced glutathione, DL-homocystine, cysteic acid, taurine, methionine sulphone, djenkolic acid, thiamine, thiazole, thioacetamide, and thiourea. Biotin, though essential for both strains, was ineffective as a sole sulphur source.The parathiotrophic strain may be a mutant lacking an enzyme at some step in conversion of sulphate to cysteine. Because of difficulties with unstable intermediate compounds, the course of cysteine biosynthesis from sulphate in D. kloeckeri could not be defined from nutritional data alone, nor could one tell which of the sequential steps is blocked in the parathiotroph.