Submitted to: Journal of Eukaryotic Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/10/2002
Publication Date: 9/23/2002
Citation: Everson, W.V., Ware, M.W., Dubey, J.P., Lindquist, H.A. 2002. Isolation of purified oocyst walls and sporocysts from toxoplasma gondii. Journal of Eukaryotic Microbiology 49:344-349. Interpretive Summary: Toxoplasma gondii is a single celled parasite. It causes abortion in livestock and mental retardation and loss of vision in congenitally infected children. Cats are the reservoir host for this parasite because they excrete environmentally resistant oocysts in their feces. Little is known about the chemical basis of resistance of these oocysts. Scientists at the Beltsville Agricultural Research Center and the Environmental Protection Agency, Cincinnati, Ohio report a method to isolate different fractions of Toxoplasma oocysts for the first time. These results will be of interest to biologists, parasitologists, and public health workers
Technical Abstract: Toxoplasma gondii oocysts are environmentally resistant and can infect virtually all warm-blooded hosts, including humans and livestock. Little is known about the biochemical basis for this resistance of oocysts, and mechanism for excystation of T. gondii sporozoites. The objective of the present study was to evaluate different methods (mechanical fragmentation, gradients, flow cytometry) to separate and purify T. gondii oocyst walls and sporocysts. Oocyst walls were successfully separated and purified using iodixanol gradients. Sporocysts were successfully separated and purified using iodixanol and Percoll gradients. Purification was also achieved by flow cytometry. Flow cytometry with fluorescence-activated cell sorting (FACS) yielded analytical quantities of oocyst walls and intact sporocysts. Flow cytometry with FACS also proved useful for quantitation of purity obtained following iodixanol gradient fractionation. Methods reported in this paper will be useful for analytical purposes, such as proteomic analysis of components unique to this life cycle stage, development of detection methods, or excystation studies.