Transport of ribitol and D-glucose in the yeast Candida guillermondii.

The uptakes of the linear polyol ribitol and of D-glucose by Candida guillermondii were found to be carrier-mediated and to require metabolic energy. In glucose-grown cells ribitol possibly enters by simple diffusion but after an induction period a specific transport system is synthesized, inhibitable by higher concentrations of arabinitols, xylitol, mannitol and sorbitol. Actidione blocks the synthesis of the inducible ribitol transport system. Two systems of different affinity for substrate were found to operate in the uptake of both glucose and of ribitol. Counter-transport experiments with ribitol, D-glucose and 3-O-methyl-D-glucose support the carrier nature of the uptake system.