Abstract
In this experiment, some environmental and nutritional factors influencing the dimorphism of some dermatophytes and dematiaceous fungi were examined. The formation of arthrospores in mycelial strains of Trichophyton mentagrophytes and T. rubrum was induced by growing the cultures under conditions of increased carbon dioxide tension or on Sabouraud's glucose liquid medium to which blood was added. T. mentagrophytes grew on an amino acid synthetic medium which resembled the composition of amino acids in hair. In this medium, in continuously agitated culture, numerous spherical cells appeared, which resembled the spores in infected hairs. When Fonsecaea pedrosoi and Phialophora dermatitidis were cultured on Sabouraud's glucose liquid media to which blood had been added, and in continuously agitated conditions, sclerotic cells were formed. However, the most suitable medium which produced the tissue phase sclerotic cells was glucose cysteine blood liquid medium (8% glucose, 1% cysteine, 10% blood) and in this medium numerous spherical cells and sclerotic cells were formed. In cultures of P. verrucosa and P. gougerotii, only a few sclerotic cells appeared.
