Induction and morphogenesis of chlamydospores in an agerminative variant of Candida albicans

A strain of Candida albicans that did not form germ tubes was endowed with a pronounced ability for massive production of chlamydospores under appropriate environmental conditions. Development of chlamydospores was induced by N-acetyl hexosamines, especially N-acetyl-D-glucosamine, and this induction did not depend on non-specific utilization of N-acetyl hexosamines as metabolic sources nor did it correlate with induction of germ-tube formation. Formation of chlamydospores in N-acetyl hexosamine-agar medium occurs through a multiplication stage (10-12 h) consisting of a few cycles of budding leading to short, "pseudo-hypha-like" structures, followed by progressive differentiation of most cells into young chlamydospores (16-18 h) which go to complete maturation in 36-48 h. There were marked differences in chlamydospore formation among different strains of C. albicans but, when induced, the morphology and kinetics of sporulation were identical in all strains. This study shows that chlamydospore formation is not necessarily associated with the mycelial phase and suggests that N-acetyl hexosamines may induce sporulation by controlling endogenous metabolism rather than through products of their own metabolism.