Figure 1

(i) Fluid phase uptake monitored using FITC-dextran. 2 mM cycloheximide inhibits fluid phase uptake by >95%, as shown in this time course. The data obtained for each experiment were normalised with respect to the 30 minute time point for Ax2 in the absence of cycloheximide. (ii) Photomicrographs of amoebae incubated with FITC-dextran. Ax2 were preincubated in the absence (A/ B) or presence (C/ D) of 2 mM cycloheximide for 30 minutes, followed by incubation with FITC-dextran. The amoebae were subsequently fixed in 5% formaldehyde and mounted on a coverslip. A, C: Phase-contrast; B, D: Fluorescence. (iii) Time course showing how membrane uptake, as monitored using FM1-43, is unaffected by cycloheximide. FM1-43 was added at a concentration of 5 μM. The data obtained for each experiment were normalised with respect to the 30 minute time point for Ax2 in the absence of cycloheximide. (iv) Internal membrane bound structures stained with FM1-43. Ax2 were preincubated for 30 minutes without (A/B) or with (C/D) 2 mM cycloheximide prior to incubation with FM1-43 for 60 minutes. The cells were subsequently washed and kept on ice before being placed on a coverslip. A, C: Phase-contrast; B, D: Fluorescence. All images are sections taken using a 60× objective lens unless otherwise stated.