Nutrient-limited yeast growth in Candida albicans: effect on yeast-mycelial transition

The yeast-mycelial transition in Candida albicans can be induced from yeast cells grown on minimal defined medium only in stationary phase. This study examined the inducibility of cultures in which growth was limited by the availability of the nutrients, glucose, NH4Cl, or galactose. The results showed that neither stationary phase nor cell cycle stage alone was a sufficient condition to support subsequent germ tube formation. In addition, final cell concentration alone was not a factor in inducibility. When a hundredfold decrease in growth was obtained by limiting any of the nutrients, a loss in inducibility was observed. However, the loss of inducibility differed with the limiting nutrient. Galactose, NH4Cl, and glucose-limited cultures showed respectively 15, 30, and 80% loss of inducibility. Thus the effect was associated with both carbon/energy and nitrogen-limited cells; however, glucose appeared to have a specific effect. These observations suggest that the metabolic state of the stationary phase yeast cell was an important factor in the subsequent ability to respond to conditions inducing germ tube formation.