Effect of glucose starvation on germ-tube production by Candida albicans

By incubating starved and unstarved yeast cells in synthetic media with a pH of 4.5 or 6.7 at 37 degrees C the effect of a 3 hours' glucose starvation on germ-tube production by Candida albicans was evaluated. In addition the endocellular content of total carbohydrates, glycogen, trehalose and proteins after and before the starvation were dosed. The most interesting result was the overcoming of the pH-regulated dimorphism, thanks to the starvation treatment. In fact the starved cultures produced germ-tubes indifferently in neutral or acid media, whereas the filamentation of the unstarved cultures was more copious in pH 6.7 medium. The endocellular content of trehalose and protein was unchanged, whereas total carbohydrates and glycogen showed a shortage after the 3 hours' glucose starvation. The possible involvements of these metabolic changes in the regulation of dimorphic transition are discussed.