Inhibition of catalase activity ofCandida albicansby serum

Abstract

The phenomenon of iron-reversible inhibition of growth of C. albicans in serum, germ-tube formation in serum, and the lack of catalase activity in cells of C. albicans grown in serum-containing media are related events which may demonstrate how initiation of widespread candidiasis is prevented in a “normal” individual. C. albicans depended on iron, added as FeCl3, for growth in neopeptone-glucose broth containing 2–25% pooled human serum. Where serum was omitted, iron additions had a negligible effect on growth.In the presence of serum, C. albicans tends to grow in the mycelial form. The germ-tubes that rapidly grow out from the yeast form are the initiation of mycelia. Addition of 0·2–0·3% phenethyl alcohol to serum resulted in the suppression of germ-tube formation, and the subsequent development of budding yeast cells. The response of C. albicans to FeCl3 in serum-containing media indicates that the mycelial form may have a metabolism requiring iron for continued growth. Since germ-tube formation also ...