Immunofluorescence assay. Fixed and permeabilized promastigotes from exponentially growing wild type (A–E), Δaah (F–J), and Δaah[pAAH] (K–O) L. donovani promastigotes were incubated with rabbit anti-AAH or guinea pig anti-IMPDH antisera, and the primary antibodies were visualized with goat anti-rabbit IgG Oregon Green-conjugated (A, F, and K) or with goat anti-guinea pig Rhodamine Red-conjugated secondary antibody (B, G, and L). The overlays of the Oregon Green and Rhodamine Red are depicted in C, H, and M, DAPI staining is shown in D, I, and N, and phase-contrast images are illustrated in E, J, and O.