Fig. 3. Toxoplasma subpellicular microtubules and spindle microtubules are differentially sensitive to disruption by oryzalin or colchicine. Phase contrast of Toxoplasma tachyzoites (arrows) grown in HFF fibroblasts in 0.5 µM oryzalin (A) or 2.5 µM oryzalin (B). Electron microscopy of Toxoplasma grown in HFF fibroblasts in 0.5 µM oryzalin (C) or 2.5 µM oryzalin (D). Arrows in (C) indicate incomplete scission between daughter parasites in 0.5 µM oryzalin. Thin sections of tachyzoites in CV2-8 CHO cells in 1.0 mM colchicine (E) or 5.0 mM colchicine (F). In all electron micrographs, the scale bar represents 2 µM. The parasitophorous vacuole membrane is designated PVM and the host cell mitochondria that surround it are labeled M. Parasites are marked ^*.