Development of microbodies in Candida tropicalis during incubation in a n-alkane medium

Development of microbodies in Candida tropicalis pK 233 was studied mainly by electron microscopical observation. The yeast cells, precultured on malt extract, scarcely contained microbodies and showed very low catalase activity. When the precultured cells were transferred to a n-alkane medium and incubated with shaking, the number of microbodies increased and concomitantly the activity of catalase was enhanced. That is, both the area ratio of microbodies in the cell and the ratio of microbodies to cytoplasm in area increased significantly during the utilization of n-alkanes for 8 hrs. Localization of catalase in the microbodies was demonstrated cytochemically by use of 3,3'-diaminobenzidine, but other organella in the cell, except for vacuoles appearing in the early growth phase and mitochondria, were not stained with this reagent. Microbodies seemed to grow by division. Biogenesis of microbodies in the yeast cells is also discussed.