Fig. 4.

PfACT1 KO merozoites remain conjoined post-egress and possess a dysmorphic ruffled surface. a Still images from Additional file 6: Video S1 show normal explosive egress in PfACT1 KOs; however, the RAP-treated population displays conjoined merozoites attached to the FV (white arrows), compared to completely segregated merozoites not attached to the FV (blue arrows) in DMSO controls. b Post-egress, Giemsa-stained RAP-treated populations have parasite structures attached to the FV (black arrow). In DMSO controls, the newly released daughter merozoites are free and not connected to the FV. Scale bar 5 μm. c Conjoined merozoites with a dysmorphic ruffled surface are apparent by SEM in the RAP-treated population. Scale bar 5 μm. d IFA on post-egress preparations of RAP-treated parasites reveals nuclei (DAPI) and micronemes (AMA1) joined to the FV, with the entire structure bounded by a contiguous plasma membrane (MSP1); defect observed in 76% of all FVs. The FV and merozoites are distinct in DMSO controls (94% of all FVs). N = 21 for DMSO and N = 33 for RAP. Scale bar 5 μm. e Free merozoites are released in the PfACT1 KO population, though they often possess a ruffled surface as observed by SEM. Scale bar 1 μm