Scanning Electron Microscopy (SEM) of <i>Toxoplasma gondii</i>-infected macrophages treated with UTP or UDP.

<p>Mouse peritoneal infected-macrophages treated with UTP or UTP for 15 minutes were incubated with 0.1% triton X-100 for 2 min before fixation for SEM (A-C), to remove the host cell plasma membrane, or dry-cleaved with adhesive tape (D-F), to expose the cytoplasm containing parasites. (A) the micrograph shows no visible parasite out of parasitophorus vacuoles. Figs (B) and (C) show parasites interacting with cytoplasmic structures. (D) the micrograph shows a parasite inside a parasitophorous vacuole, and interacting with the intravacuolar network (arrow), as expected during normal infection. Figs (E) and (F) shows egressing parasite from UTP- and UDP-treated cells, respectively, with extruded conoid structure, typical of parasites in active egress.