Candida albicans generally grows in hyphal form in RPMI-1640 medium. However, transformation of hyphal form to yeast form is observed by increasing of the cell density in RPMI-1640 medium. Intracellular Ca^ was increased in yeast growth condition (high cell density condition) compared with that of hyphal growth condition. The expression of CGR1 mRNA was inhibited in the yeast growth condition. These results indicated that the transformation of C. albicans was mediated by Ca^-dependent stimulation system, and the system was regulated by CGR1 expression
