ELECTRON MICROSCOPY OF A FISSION YEAST, SCHIZOSACCHAROMYCES POMBE

Abstract

The structure of the fission yeast, Schizosaccharomyces pombe, was studied electron microscopically, with potassium permanganate and osmium tetroxide as fixatives. The cell was found to be bounded by a cell wall, 1,000 to 2,000 A thick, and a cell membrane. A layer of material was found be-tweeen the cell membrane and the wall. The central nucleus, 2 to 3 [mu] in diameter, was bounded by a nuclear membrane, seen in some pictures to be double. Osmium tetroxide fixation revealed a granular body within the nucleus, identified as a nucleolus. Cytoplasmic structures included numerous vacuoles (probably normally containing lipid), a number of membranes and vesicles (which may represent a poorly organized mito-chondrial system), and numerous granules (probably representing ribo-somes).