THE METABOLISM OF YEAST SPORULATION: II. STIMULATION AND INHIBITION BY MONOSACCHARIDES

Abstract

Sporulation and growth of a bakers' yeast isolate were compared in 0.05 to 1% glucose, fructose, mannose, galactose, and dihydroxyacetone. Maximum yields of asci in glucose, fructose, and mannose were observed at 0.05% with a marked decline in increasing concentrations. Maximum yields of three- and four-spored asci were found at 0.1%. Galactose differed from the other hexoses in that the decline in ascus yields at higher concentrations was relatively small. The addition of 0.05% acetate increased the number of spores per ascus in the lowest concentrations of hexose. Cells grown in galactose were somewhat longer than glucose-grown cells, but not when 10−1M phosphate, 3.3 × 10−3M arsenate, or 0.033% glucose were added to the growth medium. They also formed fewer spores per ascus than glucose-grown cells. Yields of asci in dihydroxyacetone were comparable to those observed in hexose, but growth in this compound was extremely slow. No sporulation or growth was observed in DL-glyceraldehyde, DL-glyceric acid, or glycerol.