For the presidential address at the 32nd annual meeting of the Japanese Society for Medical Mycology, following statements were presented. 1. Introduction of the achievements in the studies on fungi and mycoses since the establishment of the Department of Dermatology, Niigata University School of Medicine in 1916. 2. Present conditions of dermatomycoses in Niigata prefecture were reviewed and some recent rare cases were presented. 3. Morphogenesis of cutaneous mycoses was discussed by referring some of the studies performed in our institute; they were the studies on transepidermal elimination in chromomycosis, animal model of tinea pedis, ultrastructural analysis of fungus and hair tissue in tinea capitis and sycosis trichophytica, and others.

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The relationship between respiration and morphogenesis in Candida albicans was examined using a synthetic medium which supports growth in yeast form at 25°C and that in mycelial form at 37°C. Under this condition, the amount of cellular protein increased exponentially at 25°C but linearly at 37°C. There were no essential differences in activity or characteristics of respiration between the yeast and mycelial forms, although induction of cyanide-respiration was more evident in the yeast-form cells. These results supported the view that the repression of respiration is not an essential event in the course of yeast-mycelium conversion.
Mitochondrial behaviour during budding and yeast-hypha transition was followed by staining with a fluorescent dye, 2-(4-dimethylaminostyryl)-methylpyridinium iodide (PASPMI). Yeast cells in the exponential phase contained one branched giant mitochondrion. The giant form was kept throughout the entire budding cycle, and was divided and partitioned into mother and daughter cells by cytokinesis. Upon the emergence of a germ tube from yeast cells, one end of the giant mitochondrion entered into the germ tube and developed to partially branched, elongated mitochondria. In mycelia, apical hyphal cells contained giant mitochondria, whereas elder hyphal compartments near the parent cells were vacuolated and possessed small mitochondria. The preferential localization of giant mitochondria in apical hyphae shows that the apical hyphae are the most metabolically active compartments in mycelia and can explain the linear growth of hyphae. These results were discussed on the basis of the cytological model proposed by Gow and Gooday (1985) and support the model.

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Ultrastructure of the cell wall and cytoplasm, and behavior of cytoskeletons were studied in the germ tube formation of the dimorphic yeast Candida albicans.
Mannan detected by Con A-HRP-DAB method was distributed in three layers of the cell wall, and no difference was found in localization between the two growth phases. Alkali-acid insoluble glucan consisted of a meshwork of fibrillar materials, and was more developed in the yeast phase cell than in the germ tube cells. A bundle of glucan fibrils circumscribed the mother-bud neck of the budding cells. Chitin granules were found predominantly in the germ tube but rarely in the mother cell.
A number of cytoplasmic vesicles were observed in the tip of the budding cell as well as in the germ tube apex. The germ tube showed structural differentiation from the apex to the basipetal zone similar to that seen in the filamentous fungi showing hyphal tip growth.
Cytoplasmic microtubules were more prominent in germ tube cells than in budding cells. Some of them extended to the germ tube apex. Intracellular actin granules were localized in the budding site or the germ tube apex, which suggested that actin may play an important role in the cell wall synthesis.

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For the purpose of clarifying biochemical bases involved in the regulation of morphogenesis in the dimorphic yeast Candida albicans, the relationship between the growth morphology and various biochemical activities of growth morphological mutant strains derived from the wild-type parent strain of this yeast were studied. The results are summarized as follows:
1) Based on the patterns of inhibitory activities of three selective cell wall-active agents against mycelial growth of the wild-type strain and the relation of growth morphology of the cell wall-active agent inhibitor-resistant mutant strains with their abilities to synthesize cell wall components, it appears that β-glucan synthesis plays a major role in mycelial growth.
2) In a mycelial-type mutant strain, glucose was mainly catabolized through the Embden-Meyerhof (EM) pathway, whereas in a yeast-type mutant strain glucose was mainly catabolized through the hexose monophosphate (HMP) shunt.
3) Yeast-type mutant strain exhibited significantly greater capability for synthesizing lipids than a mycelial-type mutant strain. The enzymatic activity of a yeast-type mutant strain involved in synthesis of desaturated fatty acids and phospholipids except for ergosterol and saturated fatty acids was higher than that of a mycelial-type mutant strain.
4) All these results strongly support the possibility that the activity of cell wall synthesis, particularly β-glucan synthesis, which governs the final process of morphogenesis in C. albicans may be regulated by changes of lipid components of the cell membrane via lipid metabolisms, depending upon NADPH formed through the HMP shunt and by ATP levels formed through the EM pathway for glucose metabolism.

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Alterations in lipid composition of Candida albicans were examined during the yeast (Y) to mycelial (M) transformation. A comparative lipid analysis of plasma membranes from the two cell forms showed that the sterol content of M-form cells was approximately three times greater than that of Y-form cells. ESR spectra data revealed the less fluid physical state in M-form cells than in Y-form cells.
The activity of chitin synthetase which is associated with plasma membranes was several times higher in the M-form than in the Y-form. These results suggest that modifications of membrane lipid composition play a role in the Y-M transformation of Candida albicans.
It was further observed that Y-M transformation was completely inhibited when 50% inhibition of ergosterol biosynthesis was induced by an azole-antifungal agent. On the other hand, the same degree of inhibition of ergosterol biosynthesis showed no effect on the Y-form growth, suggesting that M-form cells were more susceptible to the ergosterol deficiency than Y-form cells.

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A 5-year-old boy and his 33-year-old mother were found infected with tinea capitis associated with black dot ringworm. Typical colonies of T. violaceum were isolated from the patients on Sabouraud's dextrose agar, and macroconidium and microconidia were observed on slide culture using brain heart infusion agar enriched with thiamine. T. violaceum was also isolated both from their house dust and from the comb that they used in common. Using the hairbrush method, the fungus was isolated from their hair, too. However, after treatment the fungus could no longer be isolated from their hair nor from their house dust. These results indicate the usefulness of the above method in the evaluation of cure and prevention of recurrent infection within the family.

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The antifungal activity of GBR-14206, a new imidazole derivative, was evaluated in comparison with those of clotrimazole (CTZ) and miconazole (MCZ) using an agar dilution procedure.
GBR-14206 showed a potent activity against a wide range of pathogenic fungi including those associated with deep-seated and subcutaneous mycosis; it inhibited some standard strains of C. albicans at concentrations of 12.5μg/ml or less. Similarly, clinical isolates from various mycoses were also highly susceptible to GBR-14206 (MIC range; 0.0125-6.25μg/ml). The most striking activity of GBR-14206 was displayed against Cryptococcus neoformans (MIC range; 0.0125-0.05μg/ml), which was far superior to MCZ and CTZ. Against C. albicans, Trichophyton spp., and Microsporum spp., the activity of GBR-14206 was more moderate than MCZ and CTZ. Against Sporothrix schenckii, GBR-14206 had a lower mean MIC value than that of CTZ and was similar to MCZ. On the other hand, against Aspergillus spp., GBR-14206 was less effective than MCZ and CTZ. Fungal susceptibility of GBR-14206 tended to be enhanced with increasing medium pH. The activity was also lowered by addition of calf serum.

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GBR-14206, a new imidazole derivative, has been evaluated against systemic infection with Candida albicans in normal and immunocompromised mice. The therapeutic effect of GBR-14206 (as a lipid emulsion) given intravenously to mice infected systemically with C. albicans was superior to that of miconazole. GBR-14206 also showed a candicidal effect in the blood stream at the therapeutic dose. In addition, GBR-14206 inhibited the hyphal growth (yeast to hyphal transformation) in Eagle's minimum essential medium and methionine synthetic medium at the respective concentrations of 0.20 and 0.05μg/ml, which were approximately 3 to 7 times more active than miconazole.
These properties suggested that GBR-14206 may be useful for the therapy of systemic candidiasis in human.

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