Electron Microscopical Studies of Frozen-Dried Yeast

Open Access
Publisher Website
Google Scholar
Abstract
The periodate-Schiff reaction was used to localize polysaccharides in frozen-dried specimens of several genera of the Endomycetales, of which 3 representatives are described. No reactive cell-wall component was detectable in Schizosaccharomyces, in contrast to the distinctly reactive cell-wall layer in Nadsonia, Saccharomycodes, and Saccharomyces. These findings are in agreement with independent data from electron-diffraction studies and analytical chemistry of these genera. These and other observations suggest possibilities of phylogenetic research with the electron microscope in conjunction with cytochemical methods for comparative submicroscopic localization of cell-wall polysaccharides and the study of morphological detail during budding or other types of cell division. The structure of starch, the vacuole and its contents, and vesicular nuclei are described briefly. Basophile staining, of Nadsonia in particular, disclosed bodies tentatively identified as mitochondria pending cytochemical localization of characterizing enzymes. These structures had internal lamellations, seen as negative images, seemingly corresponding to typical osmiophilic cristae. Dense, basophile particles measuring about 60 A, hitherto not described in the mitochondrial literature, occurred in the spaces between the lamellations.