[Effect of sodium dodecyl sulfate on biological membranes].

Effect of sodium dodecyl sulfate (SDS) on yeast cells resulting in the cellular proteins release from the cells was examined. The influence of pH, ionic strength, the agent concentration and the cells lipids content on the proteins extraction degree was studied. It is assumed that the proteins release is due to the plasma membrane solubilization under the surfactant treatment.

[Comparative study of the effect of ionic and non-ionic surface-active compounds on plasmic membrane of yeast protoplasts].

Lytic effect of some cationic surface-active compounds (SAC) on yeast protoplast plasmic membrane is studied. Comparative analysis of the lytic effect of anionic, cationic and non-ionic SAC is carried out, a correlation between key physico-chemical characteristics of the agents (critical concentration of micellization, hydrophyle-lipophyle balance) and their lytic activity is investigated. A proposition is made on the presence in all biphylic compounds of a hydrophyly gradient, which is due to the effect of hydrophylic group on lipophylic properties of hydrophobic part of the molecule, and possible role of this factor in thelytic effect of biphylic compounds on biological membranes is discussed.

[Effects of non-ionogenic surface active compounds on yeast protoplasts].

The lytic effect of non-ionogenic surface active compounds (SAC), based on polyoxyethylated fatty acids and alkylphenols on the yeast protoplast cytoplasmic membranes and the extracting ability of the SAC with respect to intracellular proteins of intact yeast cells, were studied. It was shown that the lytic activity of the SAC under study depends on the overall effect of the size of their hydrophobic and hydrophylic fragments rather than on the level of the hydrophylic-lypolytic equilibrium of SAC. The absence of correlation between the lytic activity and the extracting ability of SAC is accounted for by the differences in the mechanisms of membrane degradation under the action of SAC on the protoplasts and intact cells.

[Lysis of yeast protoplasts under sodium alkyl sulfates treatment].

The lytic action of homologous series of sodium alkyl sulfates on yeast protoplasts was studied. The concentration dependences study allowed to estimate the lytic concentrations C50 of the agents required for the 50% lysis of protoplasts in the suspension. The data concerning the agents micelle formation in the lytic medium allowed to make some suggestions and to produce a model of the lytic action of alkyl sulfates on the plasma membrane of the protoplasts.

[Membrane action of ionic surfactants on yeast cells].

Effect of a number of homologous series of cationic and anionic surfactants on yeast cells was examined. It is found that the cellular proteins extraction degree under the surfactants treatment depends on the agents structure. It is established that the highest extraction efficiency among the bisquaternary ammonium compounds is displayed by the decyl derivatives and among sodium alkyl sulfates--by octyl sulfate.