THE RELATIONSHIP BETWEEN THE GLUCOSE-UPTAKE SYSTEM AND GROWTH CESSATION IN CANDIDA-ALBICANS

It is thought that dimorphic Candida albicans undergoes changes in its intracellular metabolic state prior to yeast-mycelial transformation. Cells grown in budding form to mid-exponential phase could not be ind uced to form germ tubes when grown in glucose medium. However, cells i n which growth was initially inhibited by either starvation or inhibit ors (0.1% hydroxyurea, 4% sodium malonate or 4% 2-deoxy-D-glucose) cou ld be induced to form germ tubes in the same medium. The effects of th ese initial treatments on the intracellular state in mid-exponential p hase cells were analysed by measuring the kinetics of D-glucose uptake . D-glucose uptake in mid-exponential phase and stationary phase cells was measured. The untreated mid-exponential phase cells exhibited onl y a high K-m (6.9 mM). However, mid-exponential phase cells, in which growth was initially inhibited, exhibited both a high K-m (3.2-6.2 mM) and a low K-m(0.40-0.78 mM) simultaneously. In addition, the stationa ry phase cells exhibited both a high K-m (5.6 mM) and a low K-m (0.56 mM). These results suggest that there are two kinetically distinct sys tems of glucose transport in C. albicans and that changes in the gluco se uptake system in C. albicans may be related to intracellular change s prior to transition from the budding to the mycelial form.