Plasmodium knowlesi merozoites were incubated with PKH26-labeled rhesus monkey erythrocytes at 37oC on the stage of a Zeiss Axiophot fluorescence microscope equipped with Nomarski optics. Invasion was recorded on a Westinghouse Model ETV 6006E low-light level video camera and digitized. The captured sequence is played back here in real time. The parasite is ~1 um long. Note incorporation of PKH26, a non-exchanging, fluorescent lipophilic membrane probe, into the forming parasitophorous vacuole membrane (PVM). Quantification of fluorescence intensity demonstrated that the PVM is formed from host cell lipids. See PMID 8270628 for details.