[Dynamics of cell wall formation from Trichophyton mentagrophytes protoplast]

There is no reference to the cell wall formation during the regeneration process in dermatophyte. Having succeeded in identifying the cell wall formation system of protoplast from Trichophyton mentagrophytes I introduce here the dynamics of the regeneration of this protoplast and the formation of cell wall using ultrahigh resolution low-voltage scanning electron microscopy and transmission electron microscopy (TEM), compare to the formation of yeast cell wall. Protoplasts were formed from mycelia of T. mentagrophytes; they regenerated the cell wall substances and were followed by a network of fibrils after 4-6 hr, which developed into mature mycelia after 21 hr. A network of twisted microfibrils and rope-shaped thick fiber was seen; it was covered with a sheath-shaped structure and was created on the surface of the developing mycelium. Intrafibrillar space and the surface of thick fibers were gradually filled with amorphous particles and a mature cell wall surface was formed. This protoplast regeneration was completely inhibited by the antifungal agent, lanoconazole (2 ng/ml ). The sectioned TEM image revealed that normal mycelium having a thin cell wall developed from the abortive bead-shaped mycelium which was visible in the lose fibrous structure. Based on this result and our previos work on the ultrastructure of the mycelial surface of T. rubrum with lanoconazole, a model of the cell wall composition of Trichophyton is proposed.