A study of the yeast cell wall composition and structure in response to growth conditions and mode of cultivation

Abstract

Aim: The polysaccharide composition of the Saccharomyces cerevisiae cell wall was measured under various growth conditions and was compared with the cell wall structure. Methods and Results: Chemical and enzymatic methods were used to determine levels of b-1,3-glucan and 1,6-glucan, mannan and chitin of the yeast cell wall, whereas the structure/resistance of the wall was qualitatively assessed by the sensibility to the lytic action by zymolyase. It was found that the dry mass and polysaccharides content of the cell wall could vary by more than 50% with the nature of the carbon source, nitrogen limitation, pH, temperature and aeration, and with the mode of cell cultivation (shake flasks vs controlled fermentors). While no obvious correlation could be found between b-glucan or mannan levels and the susceptibility of whole yeast cells to zymolyase, increase of b-1,6-glucan levels, albeit modest with respect to the growth conditions investigated, and to a lesser extent that of chitin, was associated with decreased sensitivity of yeast cells to the lytic action by zymolyase. Significance and Impact of the Study: Our results indicate that the cell wall structure is merely determined by cross-linking between cell wall polymers, pointed out the role of b-1,6-glucan in this process. Hence, this study reinforces the idea that enzymes involved in these cross-linking reactions are potential targets for antifungal drugs.

Extraction of cell surface‐associated proteins from living yeast cells

“…Assuming that the dry biomass of a haploid yeast cell is 15 pg (Johnston et al, 1977), and that the average molecular mass of a protein is 50 kDa, a cell contains ∼90 million protein molecules. Under the growth conditions used, the cell wall accounts for ∼20% of the dry biomass per cell, which corresponds to 3 pg (Aguilar-Uscanga and Francois, 2003;own observations). The peptide parts of the covalently bound cell wall proteins account for ∼4.3% of the wall biomass (Kapteyn et al, 2001; own observations), which corresponds to ∼0.13 pg protein or ∼1.6 million covalently linked cell wall proteins per haploid cell.…”

Study of Two Pools of Glycogen in Saccharomyces cerevisiae and their Role in Fermentation Performance

“…Glycogen as a component of the cell wall may escape detection if cells are harvested in early exponential phase for analysis 1 . It is interesting to note that cell wall bound glycogen decreases by almost (87%), while intracellular glycogen shows a 31% decrease on pitching (Fig.…”

Cell wall structure of selected yeast species as a factor of magnesium binding ability

“…The b(1,6)-glucan polymers are made up of about 130-150 glucose subunits. Their proportion in cell wall structure amounts to nearly 15 % [1,3,27]. The b(1,3)-glucan chains are linked together by b(1,6)-glucan.…”

“…In yeast cell wall, also N-acetylglucosamine polymers (chitin) occur. It constitutes up to 4 % of cell wall dry substance [1].…”

“…The yeast cell wall structure is mainly composed of polysaccharides of which content can constitute 20-90 % of this organelle dry substance [22,25,29,36]. Polysaccharides occurring in cell wall of the Saccharomyces genus are mainly b-glucans that make 30-60 % of cell wall dry substance [1,18,36]. …”