Abstract
Scales from 7 patients with Tinea versicolor and cultured Pityrosporum genus (P. orbiculare, P. ovale and P. canis) were examined.
Samples were fixed in a 5% glutaraldehyde, a 1.5% potassium permanganate and a uranyl acetate solutions. After dehydration in graded aceton series, materials were embedded in methacrylate. Ultrathin sections were prepared with a Porter-Blum MT-2B ultramicrotome, and stained with uranyl acetate and lead citrate following the Raynold's techniques. A Hitachi Hu-12 and JEM 6C electron microscope were used for the observation.
M. furfur and each Pityrosporum strain revealed very resembled structure under an electron microscope. The cell wall was thick (0.1-0.2μ) and appeared fibrous. The outersurface of the cell wall was smooth, while the inner surface, doubled by a cytoplasmic membrane, was sculptured and indented. The sculptured cell wall would be a characteristic feature of these organisumes. There were a nucleus, mitochondrias, vacuoles, endoplasmic reticulums and microbodies in the cytoplama. The electron micrograph of these intracellular organelles were similar to those of Saccharmyces cerevisiae (Vitols et al., Hashimoto et al., Linnane et al.) and Rhodotorula glutinis (Thyagarajan et al.).
Malassezia furfur was observed in three different forms-spore, budding spore and mycelium-among cornified cells. Spores were either round or oval and 3-4μ×4-5μ in size. In budding spores, a bud was round and protruded from a parent cell by the relatively broad base. The diameter of the base was 1/3-1/4 of the maximum diameter of the parent cell. A collar and a cross wall were caught in sight at the junction of certain cells. Among 3 species of Pityrosporum genus, P. orbiculare was most similar to M. furfur in regard to the shape of the bud and the diameter of the junction.
Under the ultrastructual investigation, no significant difference was recognized between M. furfur and P. orbiculare. From the above observation, the author has reached the conclusion that the Pityrosporum orbiculare and M. furfur might share the same origin.
