Effect of salinomycin on the cell volume of bloodstream forms of T. brucei . Trypanosomes (5 × 107 cell/ml) were incubated in the absence (circles) or presence (squares) of 100 μM salinomycin in culture medium. Every 15 min the absorbance at 490 nm was measured. Note that a decrease in absorbance corresponds to an increase in cell volume. Mean values ± SD of three experiments are shown.