Morphological changes of trichophyton mentagrophytes under the influence of increased carbon dioxide tension

Summary Growth pigment production as well as macroconidia and arthrospore formation ofTrichophyton mentagrophytes are stimulated under the influence of increased carbon dioxide tension. Macroconidia with spirals and pistol forms of macroconidia are observed.The granular form ofT. mentagrophytes displays an asteroid growth (Dextrose agar of Sabouraud) with an ingrowth and elongation of the ray branches in the agar and a decrease of the air-mycelium. The culture completely resembles to those ofT. mentagrophytes varasteroides. The macroconidia appear elongated and they acquire an asteroid arrangement. The less granular strains ofT. mentagrophytes take the appearance ofT. interdigitale type.An analogy is made between these morphogenetic changes under the effect of increased CO₂ tension in vitro and the influence of the animal organism in the evolution of the growth forms of dermatophytes in vivo in the process of their parasitic adaptation.