Yeast cell wall lysis

Glucanase Lysozyme Mixed Glucolytic and Proteolytic Activities Arthrobacter ssp. Yeast Cell Wall Lysis-supporting Autolysis for Production of Yeast Autolysates... 

Mechanical lysis Bacterial and yeast cell walls are disrupted by agitation with abrasives using glass beads (0.2 mm diam.) in a mill or by shearing through the small orifice of a French press at very high pressure. 

Lonvaud-Funel et al., 1988b). Glucosidase and bacterial protease activities are certainly responsible for the hydrolysis of the yeast cell wall and lead to the lysis of the entire cell. 

The removal of 30-35 % PolyPs from yeast cells during the lysis of cell walls by the snail enzyme was observed in Saccharomyces carlbergensis (Vagabov et al., 1973) - these were alkali-soluble fractions (Table 5.3). A comparative investigation of the amounts of various PolyP fractions was carried out in E. magnusii spheroplasts (Table 5.4.) and some sub-cellular fractions (Table 5.5). All of these data confirm the idea of PolyP localization in different compartments of cells of the lower eukaryotes. 

Many cells are susceptible to the appreciable shearing forces that arise on repeated freezing and thawing, or to hypotonic buffers which cause cells to swell up, and in certain cases to lyse this is particularly the case for cells in soft plant and animal tissue. Such treatments only rarely lead to complete cell lysis, the exceptions to this being erythrocytes and reticulocytes which are lysed quantitatively under hypotonic conditions. Non-mechanical homogenisation is of particular relevance to cells like yeast which are refractory to other procedures. One of the simplest procedures for yeast, which can certainly not be described as gentle, is toluene-induced autolysis. This is carried out at room temperature and leads to permeabilisation of the cell walls this causes various hydrolases to be activated causing breakdown not only of the cell structure, but also (undesirably) of many sensitive proteins and nucleic acids in the cell. Consequently, this process is mainly of historical interest. 

This paper presents two models of enzymatic lysis of yeast cells a simplified two-step model, accounting for protein release at cell lysis followed by proteolysis, and a more complex mechanistic model which describes the removal of the two layers of the yeast wall and the extrusion and rupture of the protoplast and organelles. 

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