Surface characterization of two amoebae relative to cell adhesion

Abstract

This is a comparative study of the surfaces of two Acanthamoeba castellanii strains, one of which clumps during exponential growth. Proteins from the isolated surface membranes of the strains were compared by disc electrophoresis. The number and similarity of the proteins between the two strains depended on the method of solubilization and electrophoresis. Periodic acid Schiff staining indicated that most of the proteins were glycoproteins. The molecular weights of the proteins ranged between 50 000–70 000 with those of the clumping strain being slightly larger. The non-clumping strain's surface membrane exhibited glucosyltransferase activity while the clumping strain did not. Galactosyltransferase activity was present in surface membranes of both strains but the specific activity of the clumping strain was greater. The non-clumping strain agglutinated in the presence of concanavalin A, soybean agglutinin and wheat germ agglutinin while the clumping strain was affected by soybean agglutinin only. Whole cell electrophoresis and enzymic treatments further indicated differences in the surfaces of the two strains. The data is discussed with reference to differences between the two amoebae strains and their possible role in cell-cell adhesion.