ELECTRON MICROSCOPIC STUDIES ON THE CYTOLOGICAL STRUCTURE OF TRICHOPHYTON MENTAGROPHYTES

Abstract

A combination of osmium tetroxide and several heavy metals is a good fixative for hyphal pellets of Trichophyton mentagrophytes, and staining them after sectioning is effective for enhancing the contrast in the sections. Permanganate fixation, however, is not a reliable fixative for the hyphae of a dermatophyte. The hyphal cells of the fungus show a complicated construction similar to that of other fungi or higher plant cells.
A small spherical electron-dense granule, called a peripheral (or septal) body, is found in most sections at the peripheral ends of the fungal cells located near the septal wall. This body may be a special structural component of dermatophytes which is different from a lipid storage granule, but it serves some other functions.
A nucleus-like structure with a nuclear membrane and nucleolus, which is believed to correspond to that demonstrated in yeast or animal cells, can be seen in a well prepared sectioned hyphae. However, the absence of a discrete nucleus or a nuclear apparatus in certain dermatophytes has been suggested by some workers.
The other important architectures, usually seen in yeast cells or filamentous fungi as cell wall, cytoplasmic membrane, mitochondrion, storage granule, internal double membrane, and vacuole, are also recognizable in most sections of the hyphae of a dermatophyte.