The influence of concanavalin A and cytochalasin B on pinocytotic activity inAmoeba proteus

Summary Addition of concanavalin A to a suspension ofAmoeba proteus brings about cellular agglutination and the formation of what appear to be pinocytotic channels in cell surface projections. Although concanavalin A apparently brings about pinocytotic channel formation, it does not elicit bulk medium uptake or surface membrane turnover. Cytochalasin B brings about an initial cessation of locomotion and the development of a number of randomly distributed pseudopods. After a 30 to 45 minute exposure to cytochalasin B, the cells resume their normal appearance and pattern of locomotion. Cytochalasin B itself has no influence on inducing pinocytotic channel formation or membrane turnover, but when pinocytosis is induced with 0.01% alcian blue, pinocytotic activity is greatly intensified by the presence of cytochalasin B.