Use of infected cultured cells to compare ultrastructural features of Neospora caninum from dogs and Toxoplasma gondii.
The ultrastructure of tachyzoites of 3 isolates of Neospora caninum from dogs was examined, using transmission electron microscopy of infected cultured cells. Ultrastructure of the 3 isolates was similar. Tachyzoites had a pellicle, 22 subpellicular microtubules, a conoid, anterior and posterior polar rings, 8 to 12 electron-dense rhoptries, numerous micronemes, a single vesicular nucleus, tubular mitochondria, Golgi complexes, ribosomes, endoplasmic reticula, an inactive micropore, electron-dense bodies, lipid bodies, and amylopectin bodies. Most tachyzoites were located adjacent to the host cell nucleus in a parasitophorous vacuole that contained numerous intravacuolar tubules. Tachyzoites divided by endodyogeny. Neospora caninum tissue cysts were not seen. Comparison of N caninum with Toxoplasma gondii tachyzoites indicated that the 2 species can be differentiated on the basis of structure and numbers fo rhoptries and numbers and location of micronemes and electron-dense bodies.
Lindsay
D S
DS
Department of Pathobiology, College of Veterinary Medicine, Auburn University, AL 36849-5519.
Speer
C A
CA
Toivio-Kinnucan
M A
MA
Dubey
J P
JP
Blagburn
B L
BL
D000818:Animals; D016782:Apicomplexa / Q000648:ultrastructure*; D002417:Cattle; D002478:Cells, Cultured; D004285:Dogs / Q000469:parasitology*; D006801:Humans; D014122:Toxoplasma / Q000648:ultrastructure*