The Occurrence in Yeast of Cytoplasmic Granules Which Resemble Microbodies

Microbodies and microbody-like cytoplasmic granules have been identified by ultrastructural criteria in liver and kidney cells (1, 7, 17) and in various cell types in all major plant groups (14). These or similar organelles have been shown to contain hydrogen peroxide-producing and -destroying enzymes in liver and kidney cells (2, 7-9) and in the protozoan Tetrahymena pyriformis (8). The term "peroxisome" has been introduced by de Duve and Baudhuin (11) to identify the biochemical one diploid strain, since this enzyme has been used as a peroxisome marker (7, 11). The data obtained from the electron microscopical and the biochemical analyses provided the basis for the present report, which shows the existence of cytoplasmic granules which differed from mitochondria in fine-structural features and in enzyme activity distribution.