Nutritional and environmental factors affecting the morphogenesis of Candida albicans: A key to virulence

Abstract

Candida albicans is an opportunistic fungal pathogen that plays an important role in the early part of infectious process by extravagating and disseminating to the target organs, whereas hyphal forms appear to be required for the mortality resultingfrom a deep-seated infection. C. albicans morphogenesis is regulated by numerous environmental cues and other signaling pathways. We investigated the morphogenesis in C. albicans in the presence of serum at different temperatures (20 °C, 30 °C and 37 °C). C. albicans were also grown in simple growth medium ‘SDB’ and subsequently cultured from Fetal bovine serum and Soybeans dextrose broth (SDB) on Sabouraud dextrose agar, Yeast extract potato dextrose agar and Spider medium. The combination of serum and temperature is excellent at promoting the yeast to mycelial conversion and it also induces the expression of hyphal specific genes. Our results demonstrate that the combination of serum and each temperature provides a distinct proportion of blastospores, budding yeast cells, germ tube, pseudohyphae and true hyphal cells. Remarkable change in colonial pattern between the cells cultured after incubating in serum and the cells cultured after incubating in SDB was observed in SDA in contrast with YEPD and Spider medium. On most solid media, colonies of C. albicans are composed of three types of cells: budding yeast, pseudohyphae and hyphae. All three forms are also found in infected tissues, and the transition between these forms is a key for pathogenesis.