STUDIES ON THE GROWTH OF HISTOPLASMA CAPSULATUM IV

Abstract

Various factors affecting conversion of Histoplasma capsulatum to the yeast phase have been studied. The ability of the mycelial phase to sporulate cannot be correlated with ease of conversion to yeast phase. The medium used to grow the mycelial phase may affect its subsequent ability to convert to yeast phase on a conversion medium. Conversion in vitro was found to occur in some strains at 30[degree]C. Nutritional studies have shown that the mycelial phase is strongly inhibited by the presence of citrate at 30[degree] and 37[degree]C. Ca and Mg will reverse this inhibition at 30[degree]C. The yeast phase growth is stimulated by citrate. Conversion of mycelium to yeast phase in the presence, of citrate is stimulated at 37[degree]C by Mg and Zn, while Ca inhibits this conversion.