Ultrastructure of T. gondii tachyzoites grown in HFFs. (A) Low-magnification view of infected HFFs. The boxed area is shown at a higher magnification in panel B. Tachyzoites proliferate within a parasitophorous vacuole surrounded by a parasitophorous vacuole membrane. nuc, nucleus; dg, dense granules; mic, micronemes; rop, rhoptries; mito, mitochondrion; con, conoid. The boxed area in panel B shows the mitochondrial matrix and is enlarged in panel C. Bars = 1.8 μm (A), 0.3 μm (B), and 0.1 μm (C).