FIG 9.

VGP-106 increases cytosolic Ca²⁺ levels in L. donovani. (A) Fluo-4-AM-preloaded promastigotes were treated with or without 10 or 30 μM VGP-106 for 30 min at 28°C, and the fluorescence of Fluo4-Ca²⁺ was determined. Data are means ± SD from three independent experiments. (B) Real-time Ca²⁺ determination assay carried out with promastigotes previously incubated with 5 μM Fluo4-AM treated with 30 μM VGP-106 and further analysis of the increased fluorescence. c, parasite control; c + VGP-106, fluorescence control of VGP-106 without parasites. The experiments were measured in the absence or presence of the Ca²⁺ chelator EGTA. Similar results were obtained in three independent experiments. The initial fluorescence increase is due to the intrinsic fluorescence of VGP-106 (trace c + VGP-106).