Autophagic vacuole development in Trichophyton mentagrophytes exposed in vitro to miconazole.

Trichophyton mentagrophytes was treated in vitro for 24 h with an inhibitory concentration of miconazole (10(-5) M). The youngest, apical hyphal cells showed alterations of the ultrastructure of their membranes and cell wall as well as several vacuoles of an autophagic nature. Cellular autophagy appeared as a multi-step process beginning with swelling of the endoplasmic reticulum, whose membranes later fused and gave rise to large vacuoles that entrapped previously demarcated portions of the cytoplasm. Sequestered materials, initially unaltered, were ultimately degraded. The initial event in vacuolation was interpreted as entry of water into the cells, especially into the luminal space of the endoplasmic reticulum, in response to a decrease of wall pressure on the cytoplasm.