The effects of temperature, incubation atmosphere, and medium composition on arthrospore formation in the fungus Trichophyton mentagrophytes.

Several growth conditions were found to allow abundant arthrospore formation in T. mentagrophytes. These included growth at 32--37 degrees C on Sabouraud's medium (1% neopeptone, 4% glucose) and growth at temperatures below 32 degrees C solely on neopeptone or other complex peptide sources without the addition of glucose, a supplementary carbon source. Sabouraud's medium did not allow arthropsore formation at 30 degrees C under normal atmospheric conditions. However, if oxygen tension were reduced by partial replacement of air with either N2 or CO2 arthrosporulation did occur on Sabouraud's medium at 30 degrees C. The rate of germ tube elongation was lower under those conditions which supported arthrospore formation, suggesting a correlation between decreased rate of hyphal extension and arthrospore formation. Stimulation of arthrospore formation by sublethal concentrations of several antifungal agents tends to support this hypothesis.