Importance of some factors on the dimorphism of Candida albicans.

The passage between the yeast and mycelial forms of Candida albicans B 311-10 was studied by using the minimal synthetic medium of Shepherd et al. modified without biotin and with low glucose concentrations. It was observed that biotin, aminoacids and particularly pH are not important factors in the dimorphism of C. albicans. The only factor of notable importance in the passage of yeast form to mycelial form in C. albicans was glucose concentration.

A synthetic medium for Saccharomyces cerevisiae.

Growth of Saccharomyces cerevisiae strain Castelli 20 has been observed in a minimal synthetic medium using different glucose concentrations and without biotin, during the first 30 hrs of its development at 28 degrees C. The yeast's growth was observed spectrophotometrically at 675 nm reading the Optical Density every hour. The minimal medium of Sheperd et al. (1980), with glucose 15 g/L and biotin was modified: the vitamin was eliminated and the concentration of glucose was gradually reduced down to 0.5 g/L. At 5 g/L of glucose concentration and without vitamins the strain grew very well. From our results up to 30 hrs biotin has no influence on the yeast's growth. The medium would be useful to study Saccharomyces cerevisiae physiology during the early period of its development.