TABLE 3.

pHi recovery in L. major lines^a

Buffer (pH 7.4)	Final pHi			Recovery rate
	WT	R4	revR4	WT	R4	revR4
Standard	6.73 ± 0.03	7.13 ± 0.02*	7.03 ± 0.02*	0.17 ± 0.02	0.32 ± 0.04*	0.28 ± 0.02*
DCCD (50 μM)	6.52 ± 0.04†	7.03 ± 0.03*†	6.88 ± 0.03*†	0.14 ± 0.01	0.26 ± 0.03*	0.21 ± 0.01*†
Cl−-free	6.37 ± 0.03†	6.87 ± 0.01*†	6.78 ± 0.02*†	0.06 ± 0.01†	0.18 ± 0.02*†	0.15 ± 0.02*†

^aBCECF-loaded (5 mg/ml, 30 min) WT, R4, and revR4 promastigotes were acidified by NH₄Cl pretreatment (40 mM) for 15 min and resuspended in standard or Cl⁻-free buffers at pH 7.4. The H⁺-ATPase inhibitor DCCD (dicyclohexilcarbodiimide) was added to the standard buffer at 50 μM. Rate of recovery from acidification was determined from the slope of the initial 100 s of recovery, and final intracellular pH (pHi) was determined after 10 min as described by Marchesini and Docampo (15). Data are the means ± SD from three independent experiments. Significant differences (*, P < 0.05 versus WT parasites; †, P < 0.05 versus standard buffer) were determined by Student's t test.