The Relation of Nutrition to the Growth and Morphology of Trichophyton Violaceum. I. The Vitamin and Amino Acid Requirements of T. Violaceum

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Abstract
SUMMARY1. T. violaceum grows slowly and poorly on Sabouraud's dextrose agar. The colonies are usually small, and glabrous, and consist of a mass of poorly developed mycelium and chlamydospores.2. Of eleven strains studied on synthetic, chemically defined medium, ten showed a partial requirement for thiamine. The minimum effective quantity was 0.002 μg. in 5 ml. NH4NO3 broth.3. Thiamine could be replaced for these strains by an equimolar amount of pyrimidine (2-ethoxy-methyl-6 amino pyrimidine).4. Oxalacetate was found to substitute partially for thiamine under the conditions studied.5. Growth of the thiamine-deficient strains was somewhat stimulated by comparatively large doses of para-aminobenzoic acid.6. In the presence of maximum effective dosages of thiamine, further stimulation of growth was observed with the addition of casein or other peptones.7. One strain (No. 365) was morphologically and physiologically distinct from the others in that it grew rapidly on Sabouraud's dextrose agar, producing a wh...