The anomeric specificity of monosaccharide uptake was investigated in 42 species of yeasts and related mycelium-forming fungi. Differences in the uptake of anomers were determined by the following methods. (1) Shift of anomeric equilibrium in the outer medium caused by preferential uptake of one of the anomeric forms was monitored polarimetrically as induced mutarotation. (2) The uptake of 14C-D-glucose by cells was examined after addition of freshly prepared solutions of alpha- or beta-D-glucose. Most of the organisms examined display the Saccharomyces-type preference for the alpha-anomers of glucose and xylose which is caused by the higher affinity of the monosaccharide carrier for the alpha-pyranose configuration. The following genera show this type of preference (the number of species is given in parenthesis): Saccharomyces (5), Schizosaccharomyces (1), Endomycopsis (2), Eremascus (1), Endomyces (1), Pichia (1), Hansenula (1), Debaryomyces (2), Lipomyces (1), Willia (1), Nematospora (1), Kluyveromyces (2), Candida (5), Torulopsis (5), Cryptococcus (1). No anomeric specificity was shown by the following genera: Nadsonia (1), Dipodascus (2), Rhodotorula (5), Sporobolomyces (2), Bullera (1), Rhodosporidium (1). A parallel investigation of the concentration dependence of glucose uptake indicates that most yeasts possess a constitutive monosaccharide carrier characterized by the following features: a high maximum rate of uptake, a relatively low affinity, and preference for alpha-anomers. Besides this carrier the majority of these microorganisms possess a glucose-transporting carrier with a higher affinity and a lower capacity.

• MeSH
• Biological Transport, Active MeSH
• Species Specificity MeSH
• Glucose metabolism   MeSH
• Fungi metabolism   MeSH
• Yeasts metabolism   MeSH
• Monosaccharides metabolism   MeSH
• Monosaccharide Transport Proteins MeSH
• Stereoisomerism MeSH
• Carrier Proteins metabolism   MeSH
• Xylose metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Glucose MeSH
• Monosaccharides MeSH
• Monosaccharide Transport Proteins MeSH
• Carrier Proteins MeSH
• Xylose MeSH

After growth on sucrose or glucose, Endomyces magnusii possess a monosaccharide uptake which resembles that of Saccharomyces cerevisiae (a high KT of uptake, preference for alpha-anomers of D-xylose and D-glucose, enhanced uptake during anaerobiosis, attainment of a diffusion equilibrium). The uptake is inhibited by other monosaccharides and especially strongly by D-galactose. In the absence of high concentrations of metabolizable sugars. E. magnusii develops a capacity to accumulate 3-O-methyl-D-glucose and D-xylose against a concentration gradient the new system displaying a high affinity for glucose (KT less than 0.1 mM), repression by glucose, mannose or galactose. Cycloheximide (0.2%) blocks the formation of the active system.

• MeSH
• Ascomycota metabolism   MeSH
• Galactose pharmacology   MeSH
• Glucose metabolism   MeSH
• Mannose pharmacology   MeSH
• Monosaccharides metabolism   MeSH
• Ribose pharmacology   MeSH
• Saccharomycetales metabolism   MeSH
• Sorbose pharmacology   MeSH
• Xylose metabolism   pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Galactose MeSH
• Glucose MeSH
• Mannose MeSH
• Monosaccharides MeSH
• Ribose MeSH
• Sorbose MeSH
• Xylose MeSH

• MeSH
• Biological Transport, Active MeSH
• Arabinose metabolism   MeSH
• Candida growth & development   metabolism   MeSH
• Sugar Alcohols metabolism   MeSH
• Erythritol metabolism   MeSH
• Galactose metabolism   MeSH
• Glucose metabolism   MeSH
• Carbon Isotopes MeSH
• Mannitol metabolism   MeSH
• Manometry MeSH
• Mitosporic Fungi metabolism   MeSH
• Monosaccharides metabolism   MeSH
• Ribose metabolism   MeSH
• Sorbitol metabolism   MeSH
• Sorbose metabolism   MeSH
• Stereoisomerism MeSH
• Xylitol metabolism   MeSH
• Xylose metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Arabinose MeSH
• Sugar Alcohols MeSH
• Erythritol MeSH
• Galactose MeSH
• Glucose MeSH
• Carbon Isotopes MeSH
• Mannitol MeSH
• Monosaccharides MeSH
• Ribose MeSH
• Sorbitol MeSH
• Sorbose MeSH
• Xylitol MeSH
• Xylose MeSH

• MeSH
• Aerobiosis MeSH
• Nitrates pharmacology   MeSH
• Hexoses metabolism   MeSH
• Carbon Isotopes MeSH
• Culture Media MeSH
• Pentoses metabolism   MeSH
• Cell Membrane Permeability drug effects   MeSH
• Saccharomyces drug effects   growth & development   metabolism   MeSH
• Thorium pharmacology   MeSH
• Electron Transport drug effects   MeSH
• Uranium pharmacology   MeSH
• Xylose metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Nitrates MeSH
• Hexoses MeSH
• Carbon Isotopes MeSH
• Culture Media MeSH
• Pentoses MeSH
• Thorium MeSH
• Uranium MeSH
• Xylose MeSH

Evidence for a mobile membrane carrier mediating the uphill monosaccharide transport in the yeastRhodotorula gracilis is based on two types of observations: (1) Countertransport was found with(14)C-labelledD-xylose,L-xylose,L-rhamnose and withL-rhamnose in a cell suspension preincubated with unlabelledD-xylose. This finding indicates, moreover, that both the hexoses and the pentose share the same membrane carrier. (2) The mobility of occupied carrier molecules is higher than that of free carrier molecules. This conclusion has been drawn from: (a) comparison of the initial rates of uptake of a labelled sugar into cells preincubated in the absence and in the presence of unlabelled sugar; (b) comparison on the half-saturation constant of transport with the dissociation constant of the sugar-carrier complex; and (c) comparison of the initial rates of efflux of a labelled sugar into sugar-free and sugar-containing medium.

• Publication type
• Journal Article MeSH