Abstract
Previously, we made a report on identical characteristics of nutritional requirements and physiological characters of both P. ovale and P. orbiculare. We further studied this time from morphological aspects and reached the following results: In order to prove P. orbiculare becoming similar to P. ovale under continuous subculture, we performed single spore culture. In typical round single spore culture, first flask-shaped spores appeared besides round spores then further culture revealed P. ovale like spores appeared. In flask-shaped single spore culture, P. ovale like spores appeared in much earlier stage. Single spore culture of P. ovale did not produce P. orbiculare like spores. Therefore it is considered that round spore of P. orbiculare undergo flask-shaped change then become P. ovale like shape. Human inoculation of P. orbiculare produced similar hyphae of M. furfur and P. ovale produced similar spores of P. orbiculare. Inoculation of P. orbiculare on Czapek Dox agar with amino acids added, produced hyphae. This tendency was more prominent with isoleucine added. From the above facts, both can develop into either from depending on enviromental factors and it become evident that they produced hyphae. Furthermore both fungi and M. furfur show no structural changes by electromicroscopic studies, no differences in staining and antigenicity. Also by inoculating P. orbiculare on human body, Tinea versicolor can develop and P. orbiculare can be cultured from Tinea versicolor lesion by high percentage. From these, we believe these three fungi are identical. P. pachydermatis, however, is not lipophilic, shows different antigenicity. We therefore should name this genus for Malassezia according to the nomenclature priority by disredarding Pityrosporum. Following classification seems proper. Malassezia furfur (Robin) Baillon 1884, Malassezia pachydermatis (Weidman) Dodge 1935
By measuring MIC, MCC of various antifungal agents and base materials on these fungi, low level of MIC, MCC were revealed in anti-candida agents and also base materials showed antifungal effect. In general, antifungal effects were stronger in orbiculare type fungi than ovale type and M. pachydermatis.
