FIG 4.

The Pfcrk5⁻ parasites do not undergo male gametogenesis. (A) Number of exflagellation centers per field at 15 min post activation were enumerated. Data were averaged from 3 biological replicates and presented as the mean ± standard deviation (SD). (B) and (C) IFAs performed on thin blood smears of mature stage V gametocytes activated for 20 min in vitro for WT or Pfcrk5⁻ (clone 12F) and were stained for α-tubulin (green), a male-specific marker, and Pfs25 (green), a marker for female gametes in an IFA. Anti-PfUIS4 was used to stain parasitophorous vacuolar membrane. α-Tubulin staining showed male gametes emerging from an exflagellating male gametocyte in the WT parasite. The Pfcrk5⁻ gametocytes were defective for male gametocyte exflagellation. Female gametes did not show any defect in egress from gametocyte body.