The influence of alcohols on the protoplasmic membrane and colloid models

Abstract

Experiments with colloid systems attempted to achieve a better understanding of biological processes. The influence of alcohols on phosphatid coacervates was compared with their influence upon the protoplasmic membrane of living cells of the alga Chara ceratophylla. Some similarity could be seen between the influences of methanol, ethanol and butanol. But the alcohols exerted their influence upon the living membrane at much lower concentration than they did on the phosphatid coacervates (ratio 1 : 10) and on the dielectric medium (1 : 10). Propanol, however, decreased the permeability of the living protoplast, in the opinion of the author by condensation of the membrane, but opened up the phosphatid coacervate. Very low concentrations of propanol could, however, increase the permeability of the protoplasmic membrane in a similar way as it increased the volume of the coacervate. In explaining the influence of alcohols on the permeability of the protoplasmic membrane the author considered: action on the carbon chains of the membrane components; action on the dielectric condition of the system; the structure of the system (amorphous or oriented). The use of phosphatid coacervates as a model did not mean that the protoplasmic membrane was thought to be an amorphous system. Alcohols would probably open up a protoplasmic membrane composed of oriented components.