MacQuillan, Anthony M. (The University of Wisconsin, Madison) and Harlyn O. Halvorson. Physiological changes occuring in yeast undergoing glucose repression. J. Bacteriol. 84:31-36. 1962.-Growth of the hybrid yeast Saccharomyces fragilis x S. dobzhanskii on glucose or lactate resulted in (i) the possible impairment of a permeation system for succinic acid, (ii) the repression of succinic and isocitric dehydrogenases and beta-glucosidase, and (iii) the induction of isocitratase. The latter two changes were not observed in S. lactis Y14, in which beta-glucosidase synthesis is resistant to glucose repression.