Cho T, Hagihara Y, Kaminishi H, Watanabe K
Department of Oral Microbiology, Fukuoka Dental College, Japan.
J Med Vet Mycol. 1994 Dec;32(6):461-6. doi: 10.1080/02681219480000611.
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 induced to form germ tubes when grown in glucose medium. However, cells in which growth was initially inhibited by either starvation or inhibitors (0.1% hydroxyurea, 4% sodium malonate or 4% 2-deoxy-D-glucose) could be induced to form germ tubes in the same medium. The effects of these initial treatments on the intracellular state in mid-exponential phase 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 only a high Km (6.9 mM). However, mid-exponential phase cells, in which growth was initially inhibited, exhibited both a high Km (3.2-6.2 mM) and a low Km (0.40-0.78 mM) simultaneously. In addition, the stationary phase cells exhibited both a high Km (5.6 mM) and a low Km (0.56 mM). These results suggest that there are two kinetically distinct systems of glucose transport in C. albicans and that changes in the glucose uptake system in C. albicans may be related to intracellular changes prior to transition from the budding to the mycelial form.
据认为，二态性白色念珠菌在酵母-菌丝体转变之前其细胞内代谢状态会发生变化。在葡萄糖培养基中，以芽殖形式生长至指数中期的细胞不能被诱导形成芽管。然而，最初生长受到饥饿或抑制剂（0.1%羟基脲、4%丙二酸钠或4% 2-脱氧-D-葡萄糖）抑制的细胞，在相同培养基中可被诱导形成芽管。通过测量D-葡萄糖摄取动力学，分析了这些初始处理对指数中期细胞内状态的影响。测定了指数中期和稳定期细胞的D-葡萄糖摄取。未处理的指数中期细胞仅表现出高Km（6.9 mM）。然而，最初生长受到抑制的指数中期细胞同时表现出高Km（3.2 - 6.2 mM）和低Km（0.40 - 0.78 mM）。此外，稳定期细胞同时表现出高Km（5.6 mM）和低Km（0.56 mM）。这些结果表明，白色念珠菌中存在两种动力学上不同的葡萄糖转运系统，并且白色念珠菌中葡萄糖摄取系统的变化可能与从芽殖形式转变为菌丝体形式之前的细胞内变化有关。
