[Capsule formation in saprophytic yeasts]

Among ten carbon sources and five nitrogen sources tested, D-mannose (3%) and peptone (0.2%) were found to be the best ones for stimulating capsule formation by the yeast Cryptococcus magnus. Addition of yeast extract (0.1%) to the medium favoured formation of larger capsules. Elevated concentrations of mannose and peptone inhibited capsule formation. Comparison of the results obtained with the data about the effect of cultivation conditions on capsule formation by the pathogenic yeast revealed no considerable differences between the latter and the saprophytic yeast.