Studies on the Cytological Structure of Yeast: Electron Microscopy of Thin Sections

Abstract

Ultrathin sections of Saccharomyces cerevisiae, grown on Lindegren's presporulation medium, have been studied with the electron microscope. A cytoplasmic membrane, mitochondria, nucleus, central vacuole, storage granules, and an internal double membrane system have been described. The cytoplasmic structures observed resemble closely analogous structures described in thin sections of cells from a variety of other sources.

Ultrastructural Features of the Invasive Phase of Candida Albicans

“…Finally, in close proximity to both, is a " storage granule " which is, however, of similar size and with granular eontcnts of similar density to the mitochondria, and which could be regarded as representing a further stage in the loss of identifying detail. DISCUSSION AU the structures described above have been demonstrated in the yeast form (blastospores) of C. albicans or S. cerevisiae by previous workers such as Palade and Porter (1954), Agar and Douglas (1957), Gale (19G3), Bakerspiegel (1964) and Tsukahara and Sato (1964). In these preparations of yeasts or blastospores, however, the details of the membranous organelles and of the membranes themselves tend to be obscured by electron-dense, granular material.…”

“…Storage granules and Iipid bodies.-A number of areas are seen with what seems to consist of a single limiting membrane and dense, granular contents. These may be somewhat unimaginatively termed " storage granules ", and resemble those described by Agar and Douglas (1957) in Saccharomyces cerevisiae. It will be seen, however, in Fig.…”

Comparative Cytology and the Evolution of Life

“…7). Under the electron microscope, this nucleoplasmic mass has the appearance typical of nucleoplasm of higher organisms and is enclosed in a membrane (Bartholomew and Levin, 1955;Agar and Douglas, 1957); hence the interpretation of these structures offered here may have some validity. But this point is of no particular consequence to the main thesis, as the hypothetical stage will suffice for our needs.…”

“…These grains, because of their minute size and apparent lack of the proper internal construction, appear to be not true mitochondria but forerunners of the same, and might well be designated as promitochondria. The true mitochondrion appears in its simplest form in the yeasts such as Saccharomyces (Agar and Douglas, 1957) , here consisting of a membrane (whether single or double cannot be determined at present) with only a few internal folds which are obviously broad invaginations of the enveloping vestment. In the euglenoids only a slightly more advanced condition prevails, the internal folds being more numerous and less clearly derived from the investing membrane (Wolken, 1956).…”

ELECTRON MICROSCOPY OF CULTURED SPHERULES OF COCCIDIOIDES IMMITIS

“…In the early stages of cleavage there appears to be very little visible structure in the septa, but the lamellatcd appearance becomes evident as they grow and the new wall develops. X 11,500. and Saccharomyces cerevisiae (18), in which the membrane shows marked invaginations, in C. immitis the membrane is at best described merely as irregular. Endospores are formed in this organism by the invagination of the cytoplasmic membrane, preceding the deposition of the septal material in close association with the folded membrane.…”