Holmes A R, Cannon R D, Shepherd M G
Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
Oral Microbiol Immunol. 1992 Feb;7(1):32-7. doi: 10.1111/j.1399-302x.1992.tb00017.x.
Cultures of Candida albicans yeast cells do not normally aggregate, but extensive aggregation accompanies the induction of mycelial growth, indicating the occurrence of cell surface changes during the yeast to mycelial transition. Aggregation correlated with the formation of germ tubes as did changes in surface charge determined by attachment to ion exchange sepharose beads. Yeast cells of all strains examined were negatively charged and attachment to positively charged (DEAE) sepharose beads increased following germ tube formation. If Mg2+ was present during germ tube formation, a high degree of clumping occurred that could only be dispersed by treatment with protein-disrupting agents. Trypsin, chymotrypsin, SDS, urea, guanidine HCl and dithiothreitol but not EDTA or EGTA caused irreversible dispersal of aggregates, although germ tube aggregates dispersed by treatment with buffers at high pH reaggregated if neutralized or if calcium ions were added. Germ tube cultures produced in divalent cation-deprived medium formed aggregates that were readily dispersed by washing. However, the addition of Mg2+ or other divalent cations (Ca2+, Zn2+, Cu2+, Fe2+) caused immediate aggregation of these cultures. These results suggest that divalent cation crossbridging between opposing anionic sites and protein interactions act synergistically to promote aggregation of C. albicans germ tube cells.
白色念珠菌酵母细胞的培养物通常不会聚集，但在菌丝体生长诱导过程中会出现广泛聚集，这表明在酵母向菌丝体转变过程中发生了细胞表面变化。聚集与芽管的形成相关，通过与离子交换琼脂糖珠结合测定的表面电荷变化也与之相关。所有检测菌株的酵母细胞均带负电荷，芽管形成后与带正电荷（DEAE）的琼脂糖珠的结合增加。如果在芽管形成过程中存在Mg2+，则会发生高度聚集，只有用蛋白质破坏剂处理才能使其分散。胰蛋白酶、胰凝乳蛋白酶、SDS、尿素、盐酸胍和二硫苏糖醇可导致聚集物不可逆地分散，但EDTA或EGTA则不能，不过用高pH缓冲液处理分散的芽管聚集物，如果中和或添加钙离子则会重新聚集。在缺乏二价阳离子的培养基中产生的芽管培养物形成的聚集物，通过洗涤很容易分散。然而，添加Mg2+或其他二价阳离子（Ca2+、Zn2+、Cu2+、Fe2+）会导致这些培养物立即聚集。这些结果表明，相反阴离子位点之间的二价阳离子交联和蛋白质相互作用协同作用，促进白色念珠菌芽管细胞的聚集。
