THE EFFECT OF AN ABRUPT STEPWISE REDUCTION IN PRESSURE ON THE INTEGRITY OF THE EUKARYOTIC AND PROKARYOTIC CELL-ENVELOPE

The influence of an abrupt pressure variation on cell integrity was st udied in the case of Saccharomyces cerevisiae, Escherichia coli, and c hinese hamster ovarian and tobacco cells. Experiments were carried out with a new design of normal stress generator operating without any ga s. The cells were immersed in a liquid phase to avoid any shear stress . The influence of the cell physiologic state was studied by harvestin g cell suspensions at different batch culture times. No shearing effec t or loss of membrane integrity was obtained, whatever cell type was c onsidered; there was no significant difference in cellular protein and enzyme concentration in the extracellular medium, before and after th e pressure shock. These results show that the cell envelope's role of barrier to large molecules was not modified by a rapid pressure variat ion.