Influence of different fixing agents on lectin binding by the Tetrahymena

Binding studies on membranes of unicellulars are most conveniently performed in fixed preparations, in which phagocytotic activity does not interfere with the membrane-ligand inter-actions. The fixing procedure may, however, considerably alter the interrelationships between membrane components, and the quality and quantity of the groups capable of binding. We examined the influence of 8 different fixatives on binding of 7 lectins of dissimilar sugar specificity to the membrane of Tetrahymena pyriformis GL strain. The quantitative relations of binding were found to vary markedly with the type of fixing agent, and disparities of the binding pattern between body regions have suggested regional variations in membrane composition. It follows that the results of binding experiments are not comparable unless the same fixing agents has been used.