ABSTRACT
This paper deals with microheterogeneity in the structure of O-linked sugars of carbohydrases secreted by Asp. awamori, namely glucoamylase, alpha-galactosidase and alpha-glucosidase. Microheterogeneity was found to be related both to post-secretion deglycosylation and to changes in transferase activity induced by the differences in culturing conditions.
Subject(s)
Aspergillus/enzymology , Galactosidases/chemistry , Glucan 1,4-alpha-Glucosidase/chemistry , Glucosidases/chemistry , Aspergillus/growth & development , Carbohydrate Sequence , Culture Media , Galactose/analysis , Galactosidases/metabolism , Glucan 1,4-alpha-Glucosidase/metabolism , Glucosidases/metabolism , Glycosylation , Mannose/analysis , Molecular Sequence DataABSTRACT
A method is proposed that allows to choose among the polyene-resistant mutants of the yeasts Saccharomyces cerevisiae with changed biosynthesis of ergosterol promising producers of provitamin D4 and structural analogs of provitamin D3. The method involves both UV-spectrophotometry and thin-layer chromatography. The results obtained are supported by the data of mass-spectrometry of sterols.
Subject(s)
Saccharomyces cerevisiae/metabolism , Sterols/metabolism , Vitamin D/biosynthesis , Chromatography, Thin Layer , Drug Resistance, Microbial , Mutation , Prodrugs , Saccharomyces cerevisiae/genetics , Spectrophotometry, UltravioletABSTRACT
The sterol composition of nystatin-sensitive and nystatin-resistant strains of Saccharomyces cerevisiae was being studied by gas-liquid chromatography and mass-spectroscopy. The synthesis of ergosterol is completely suppressed in polyene-resistant mutants. Three sterols derived from cholesterol were identified in the mutants: cholesta-8,24-diene-3 beta-ol, cholesta-5,7,24-triene-3 beta-ol, and cholesta-5,7,22,24-tetraene-3 beta-ol.
Subject(s)
Nystatin/pharmacology , Saccharomyces cerevisiae/analysis , Sterols/analysis , Chromatography, Gas , Drug Resistance, Microbial , Mass Spectrometry , Mutation , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/geneticsABSTRACT
The recessive yeast mutations nys providing resistance to polyene antibiotics in Saccharomyces cerevisiae are described. The analysis of UV-absorbtion spectra of sterols from cells of different mutants allows to assume that NYS genes control synthesis of ergosterol. The lack of alterations in the sterol composition of the same strains carrying dominant nystatin resistance mutations points to the existence of another mechanisms of resistance to polyene antibiotics, in addition to the sterol mechanism.
