title: Structure of Sarcocystis neurona sarcocysts.
abstract: The ultrastructure of Sarcocystis neurona sarcocysts was studied from muscle of an experimentally infected cat. The cat was killed 144 days after being fed sporocysts from a naturally infected opossum. Sarcocysts were microscopic, up to 700 microm long, and up to 50 microm wide. By light microscopy, the sarcocyst wall was 1-2 microm thick. Ultrastructurally, the sarcocyst wall consisted of numerous villar protrusions. The villar protrusions were up to 2.8 microm long and 0.4 microm wide, with a tapered end. Microtubules extended from the tip of the villus to the base and occasionally extended deep into the granular layer. The granular layer was approximately 0.5 microm thick. Longitudinally cut bradyzoites were 5.2 by 1.2 (4.8-6.5 by 1.0-1.3) microm in size. Micronemes in bradyzoites were numerous and located in the anterior 1/3 of the conoidal end.
authors.affiliation: Parasite Biology, Epidemiology and Systematics Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland 20705-2350, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.forename: D S
authors.initials: DS
authors.lastname: Lindsay
authors.forename: D
authors.initials: D
authors.lastname: Fritz
authors.forename: C A
authors.initials: CA
authors.lastname: Speer
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000469:parasitology* / Q000473:pathology; D002415:Cats; D018482:Muscle, Skeletal / Q000469:parasitology / Q000473:pathology* / Q000648:ultrastructure; D009893:Opossums; D012522:Sarcocystis / Q000648:ultrastructure; D012523:Sarcocystosis / Q000473:pathology / Q000662:veterinary*