Saccharomyces cerevisiae cell division cycle

R. J. Gillies, K. Ugurbil, J. A. den Hollander and R. G. Shulman (1981). 31P NMR studies of intracellular pH and phosphate metabolism during cell division cycle of Saccharomyces cerevisiae. Proc. Natl. Acad. Sci. USA, 78, 2125-2129. 

Figure 9.9 A schematic representation of the cell cycle of a budding wine yeast cell. Haploid and diploid cells reproduce asexually by multilateral budding during which each cell gives rise to a daughter cell made of entirely new cell surface material. Buds may arise at any point on the mother cell surface, but never again at the same site. Under optimal nutritional and cultural conditions Saccharomyces cerevisiae doubles its mass every 90 min. The cell division cycle consists of four phases Gl, S, G2 and M.

The overall life cycle of a particular yeast Saccharomyces (S.) cerevisiae, is summarised in Fig. S.6 which shows how it is possible for the cells to fuse to form various cell and spore types. The figure shows the possible types of reproduction in yeast. Generally, industrial strains of S. cerevisiae, brewers yeast, reproduce by budding/ fission processes and only sporulate under specialised conditions. However, many strains of yeast are capable of cell fusion to form spores or cells with increased genetic complements. Such strains have many sets of chromosomes and are termed polyploid. Active fermentation of industrial strains involves growth by mitotic division and nutrient depletion which results in stationary cells with little or no spore formation. 

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