Observation on the nucleic acids in the chlamydospores of Candida albicans.

The presence of red (RNA) and green (DNA) fluorescent material identifying nucleic acids in the chlamydospores of Candida albicans has been well documented. Red fluorescence in chlamydospores is relatively diffused and ranges from small spots, observed in hyphal cells, to the entire protoplasmic content. Green fluorescence is rarely visible in these structures and, when present it can be observed next to the plasmalemma. The initial percentage values of the two curves related to the cell counts of red fluorescence of the suspensor cells and chlamydospores showed remarkable differences between the two structures. About 54% of the chlamydospores showed red fluorescence compared to about 28% of the suspensor cells. It seems from the results obtained in this study that much RNA was produced and/or accumulated in the chlamydospores and suspensor cells, rather than in mycelium where red fluorescence was not observed. The results obtained sustain the hypothesis that a chlamydospore should he considered a fully functional cell that is morphologically and physiologically active and independent from mycelium.

Glucose influence on germ tube production in Candida albicans.

The influence of different glucose concentrations was tested in minimal synthetic medium on Candida albicans strain. After 18 hours of starvation, germ-tube (GT) production, amount of consumed glucose, oxygen and the pH of the medium were checked every hour from the beginning through the end of the experiment. Optimal GT production was obtained with 1 g/l of glucose. At this concentration the greatest glucose and oxygen consumption were also noted. No pH variations in the medium were observed in all of the glucose concentrations used. At 3 and 5 g/l glucose concentrations a lower GT production were obtained. The Crab-tree effect might interfere with GT production when glucose concentration is higher than 1 g/l. This data may support the hypothesis that GT production is strictly glucose dependent.

Influence of fructose on Candida albicans germ tube production.

The influence of different fructose concentrations (5, 3, 1 and 0 g/l) was tested on Germ Tube (GT) production by Candida albicans strain AS3P, using a Minimal Synthetic Medium (MSM) without (NH4)2SO4. The results obtained showed good GT production in the presence of all the different fructose concentrations and in the absence of any nitrogen source. The greatest GT production was obtained with 3 g/l of fructose vs 1 g/l of glucose, after 4 hr of incubation. On the other hand fructose consumption was lower than that of glucose at all concentrations over the 4 hour period. The data obtained may suggest that fructose is metabolized in a different way from glucose for GT production by C. albicans.