The septal ontogeny, germination and electron microscopy of Microsporum gypseum macroaleurioconidia.

Microsporum gypseum strains obtained from human and animal cases of dermatophytosis were used to study the septal ontogeny, the germination, and the electron microscopy of the macroaleurioconidia, which are produced so abundantly by this organism. It was found that the number of septa in a macroaleurioconidium depends upon the stage of development, and that their order of formation remains relatively constant. The macroaleurioconidial cell wall proved to be impressive on electron microscopy. The use of a wetting agent (Tween 80) and negative pressure proved necessary for adequate fixation. Poor penetration of the fixing agent is attributable to the electron-dense encrustations over the entire surface of the macroaleurioconidium.