Figure 6. Effects of MBHA3 treatment on the acidic compartments of T. cruzi.

(A) Overlay flow cytometric histograms of the control and treated-cells labeled with AO, after 72 hours of drug incubation. A gradual shift of the red fluorescence could be observed in the cells treated with the IC₅₀ and the 2x IC₅₀ of MBHA3. Nevertheless, in cells treated with the 4x IC₅₀ of MBHA3, a striking decrease of the fluorescent signal from red channel was observed. (B–E). Confocal microscopy images of the control (B) and treated-cells (C–E). Control cells presented a normal morphology with a bright green nucleus, pale green cytoplasm and large red-labeled compartments at the posterior end of cells (B). Detail of the IC₅₀-treated culture showing slight changes in the parasite nucleus. (C). Aspect of parasite culture treated with the 2x IC₅₀ of MBHA3 showing severe acidification of the parasite cytoplasm (D). Note the presence of the pyknotic nucleus (white arrow, inset). Parasites treated with the 4x IC₅₀ of MBHA3 showed a round-shape body and a decrease in both green and red AO fluorescent signals (E).