FIG. 1.

[³H]diminazene aceturate uptake in bloodstream form T. brucei brucei. The uptake of 50 nM [³H]diminazene aceturate by T. brucei brucei 427 (boxes) or Tbat1^−/− (circles) in the presence (solid symbols) or absence (open symbols) of 1 mM unlabeled diminazene aceturate was determined over various time intervals as indicated. Uptake by strain 427 in the absence of unlabeled excess permeant was 0.0086 ± 0.0005 pmol 10⁷ cells⁻¹ s⁻¹ (linear regression, r² = 0.96). In the presence of 1 mM diminazene aceturate, uptake was not significantly different from zero (P = 0.26 [F-test]). Although the slope for diminazene transport by Tbat1^−/− was significantly different from zero (P < 0.01), the rate of transport over 120 s was 98.9% reduced in this line.