ISOLATION AND CHARACTERIZATION OF A RHODOTORULA-GLUTINIS MUTANT DEFECTIVE IN GLUCOSE-TRANSPORT

Mutants of the obligatorily aerobic yeast Rhodotorula glutinis, obtained by treating wild-type cells with N-methyl-N'-nitro-N-nitrosoguanidine, were selected on fructose medium containing 1% 2-deoxy-D-glucose. One mutant, designated R33, displayed a significantly decreased initial rate of uptake of D-glucose, 2-deoxy-D-glucose, D-galactose and D-xylose, and was unable to accumulate the latter three sugars. However, the residual monosaccharide transport was still energy-dependent. The mutant displayed significantly altered transport parameters for D-glucose and D-xylose. These results are evidence for the isolation of a mutant defective in the glucose carrier.