title: Mode of action of ponazuril against Toxoplasma gondii tachyzoites in cell culture.
abstract: Toxoplasma gondii is an important apicomplexan parasite of humans and other warm-blooded animals. Ponazuril is a triazine anticoccidial recently approved for use in horses in the United States. We investigated the mode of action of ponazuril against developing RH strain T. gondii tachyzoites in African green monkey kidney cells. Host cells were infected with 2.0 x 10(5) tachyzoites and treated with 5 microg/ml ponazuril. Cultures were fixed and examined by transmission electron microscopy 3 days after treatment. Ponazuril interfered with normal parasite division. This led to the presence of multinucleate schizonts stages. Up to six tachyzoites were observed partially budded from the surface of these schizonts. Large vacuoles developed in these schizonts and they eventually degenerated.
authors.affiliation: Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, 1410 Prices Fork Road, Blacksburg, Virginia 24061-0342, USA.
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Mitchell
authors.forename: Anne M
authors.initials: AM
authors.lastname: Zajac
authors.forename: Wendell L
authors.initials: WL
authors.lastname: Davis
authors.forename: David S
authors.initials: DS
authors.lastname: Lindsay
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000633:toxicity*; D002460:Cell Line; D002522:Chlorocebus aethiops; D007668:Kidney; D014122:Toxoplasma / Q000187:drug effects* / Q000254:growth & development* / Q000648:ultrastructure; D014227:Triazines / Q000633:toxicity*
chemical_list: D000981:Antiprotozoal Agents; D014227:Triazines; C415002:ponazuril