The effect of alfalfa saponins on growth and lysis of Physarum polycephalum.

The prelytic events associated with the interaction of saponins with Physarum polycephalum membrane components were studied. It was found that alfalfa saponins form interaction products with membranal sterols, proteins and phospholipids. The interaction of saponins with proteins affect also certain membranal enzymic activities such as NADH oxidase and Malate dehydrogenase. It is suggested that although the interaction of the saponin with sterols is much more specific than with other membranal components, the lysis of plasmodia of P. polycephalum should be attributed to a concerted attack on the various membrane constituents. In continuation of these interactions, the changes of permeability of plasmodia membrane were expressed by increment of inorganic sodium ions and water influx, traced by lysis, while no efflux of ions was observed.