FIG 2.

Effects of SQ109 on the proton motive force (PMF) in digitonin-permeabilized T. cruzi. Epimastigotes (10⁸ cells) were added to buffer (2.4 ml) containing 2 mM succinate and 5 μM safranine, and the reaction was initiated with or without (gray trace in panel A) 60 μM digitonin. (A) SQ109 (10 μM) and FCCP (8 μM) were added where indicated. (B) ADP (10 μM), oligomycin (Oligo) (2 μg/ml), CaCl₂ (16 μM), EGTA (200 μM), SQ109 (10 μM), and FCCP (8 μM) were added where indicated. (C) CaCl₂ (16 μM), EGTA (200 μM), various concentrations (0 to 40 μM) of SQ109, and FCCP (8 μM) were added where indicated. (D) Changes in safranine fluorescence after addition of SQ109 (4 to 40 μM) or FCCP (8 μM), as shown in panel C. The results are the means ± standard deviation (SD) values from three independent experiments.