Recent, new and exciting developments and changes in the taxonomy of medically important fungi are reviewed and discussed. A number of the major genera and species have been reevaluated, some redefined, and others named as new taxa. Many taxonomic problems have been resolved owing to a better appreciation and understanding of conidiogenesis, morphogenesis, metabolic pathways, serological characters, and the cellular components of the fungi.
A better appreciation of anamorph(s)-teleomorph connections will aid medical mycologists in understanding the whole fungus. Several problems, however, still exist, which require additional data before they can be adequately resolved.

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This experiment deals with the reproductive cycle of spherules in vivo and the tissue responses to C. immitis infection. Ten congenitally athymic nude (nu/nu) mice were used for the study of the reproductive cycle of the spherule and 16 Swiss white mice, for the study of the tissue responses to the fungal infection. Each nu/nu mouse was inoculated intraperitoneally with 10⁵ arthroconidia and two mice were sacrificed 2, 4, 8, 10 and 12 days after inoculation. On the other hand, each Swiss white mouse was infected intravenously with 5×10⁴ arthroconidia and two mice were sacrificed 1, 2, 4, 6, 8, 10, 14 and 18 days after inoculation. Then, histopathologic sections were prepared from various internal organs. Arthroconidia transformed to spherules within 4 days. Young spherules before cleavage consisted of two zones. The protoplasm was distributed peripherally and formed the outer zone. The inner zone was stained positively by PAS. With the start of cleavage in the protoplasm, the PAS-positive substance disappeared and a vacuole appeared. Cleavage furrows occurred from the wall of the spherule, grew inward and ramified, and the protoplasm was divided into small masses (cleavage partitions) containing nuclei. Then, an outline of endospores began to appear in each cleavage partitions and clusters of the endospores were formed. Through these processes spherules were filled with uninucleate endospores. With the rupture of the wall of the spherule these endospores were released and the same reproductive cycle repeated in the tissue. In the Swiss white mice inoculated intravenously with the fungus the liver, lung and spleen were severely affected. Concerning the tissue responses to the fungal infection a marked purulent inflammatory reaction occurred when the reproductive cycle of the spherule progressed actively. On the other hand, when its reproductive activity declined, mononuclear cells began to accumulate at the foci and changed the histopathologic characters from pyogenic to granulomatous.

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Experiments were designed to establish the suitable models for the study of experimental candidiasis. Following three results were obtained from the present study. First, mice were inoculated intratracheally with Candida albicans to induce lung candidiasis. All mice died within 6 days after intratracheal inoculation with more than 7.5×10⁶ CFU of C. albicans. Second, rats were infected intravenously with C. albicans after a polyethylene catheter was placed in the left ventricle through the right carotid artery. The catheterized rats died from endocarditis when they were infected with a small number of C. albicans which were not enough to kill normal rats. Third, effectiveness of the immunization with γ-irradiated candida cells against the infection was confirmed in those two models. This fact indicates that those new models are useful for basic research on experimental candidiasis.

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Ketoconazole, a new imidazole derivative, and griseofulvin, are the two most valuable oral antimycotics for oral administration in the treatment of dermatophytosis. The antifungal properties of ketoconazole were compared in vitro with those of griseofulvin using a liquid microculture method and 68 clinical isolates of dermatophytes. Both drugs showed minimal inhibitory concentration (MIC) values of ≤5μg/ml for all isolates of Trichophyton rubrum. The MIC values of griseofulvin for 90% of Trichophyton mentagrophytes isolates ranged from 0.5 to 3μg/ml; the MIC values of ketoconazole for Trichophyton mentagrophytes ranged from 0.5 to 5μg/ml or greater. Microsporum species were 2.3-6.3 times more susceptible to griseofulvin than to ketoconazole; Epidermophyton floccosum was uniquely susceptible to both drugs.

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Keratinase isolated and purified from Microsporum canis could digest the tonofilament of the human horny layer as observed by the electron microscopy. Keratinase isolated from Microsporum canis and Trichophyton rubrum gave identical precipitin line by the double immunodiffusion method.
The skin of the tinea corporis infected with T. rubrum was investigated using the antiserum against keratinase from M. canis with an immunoperoxidase staining method. On the light microscope, keratinase was found around fungal cells in the human horny layer. And the immunoelectron microscopic investigation of fungi removed from the culture medium, keratinase was localized in the plasma membrane and around the fungal cell wall. These results suggests that the dermatophytes will take the nutritive substances from the keratinized structure such as the human horny layer using keratinase.

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Of a series of studies on the antifungal activities of sulconazole nitrate, a newly developed imizdazole antimycotic, this paper describes its in vitro antifungal activities against a variety of pathogenic fungi. The minimum inhibitory concentrations of the drug were determined by means of agar dilution method in comparison with econazole nitrate, using Sabouraud dextrose agar plates. As a result, sulconazole nitrate was found to exhibit a potent inhibitory effect with a broad spectrum, particularly against Cryptococcus neoformans, dermatophytes, dematiaceous fungi and dimorphic fungi.

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