FIG. 5.

Maximal uptake of radiolabel in mature infected erythrocytes. Data for three uptake experiments with mature infected erythrocytes are presented. In the first experiment (solid lines and circles), the total average amount of radiolabel in each sample (horizontal solid line) and the amount associated with mature infected erythrocytes only over time are presented (shown as counts per minute [CPM]), which were determined by using a starting concentration of 0.4 μM radiolabeled artemisone (note that ∼60% of radiolabel is taken up by the cells in this example). In the second experiment (long dashed lines and squares), data are presented as described above but were determined by using medium containing 0.4 μM radiolabeled artemisone that had first been exposed to mature infected erythrocytes for 20 min before use (note that only ∼40% of the original radiolabel is measureable after this procedure and that this radiolabel is unable to be taken up into fresh mature infected erythrocytes). In the third experiment (short dashed lines and triangles), data are presented as described above for the first experiment but were determined by using a starting concentration of 0.16 μM radiolabeled artemisone, which served as a control.