Ultrastructure of Sporozoites and Zoites of Hammondia heydorni |
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Authors: | C A SPEER J P DUBEY |
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Institution: | Veterinary Research Laboratory, Montana State University, Bozeman, Montana 59717 and Zoonotic Diseases Laboratory Livestock and Poultry Sciences Institute, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705 |
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Abstract: | The ultrastructure of sporozoites and zoites of Hammondia heydorni was studied in cultured bovine cells. In addition to ultrastructural features typical of coccidian parasites, H. heydorni sporozoites and zoites contain rhoptries that are located posteriorly as well as anteriorly. Also, sporozoites contain a posteriorly located crystalloid body (1.2 μm in diameter); a small crystalloid body (0.5 μm in diameter) was occasionally seen in the anterior end. Zoites resulting from the 1st division of endodyogeny contain a posteriorly located crystalloid body, which is absent in zoites formed by subsequent divisions. Zoites contain posteriorly located amylopectin granules and a relatively large anterior vacuole which is not present in sporozoites. During penetration, the host cell plasmalemma ballooned laterally around the sporozoite creating a large cavity, which later disappeared. Sporozoites and zoites undergoing cell penetration usually exhibit partially empty anterior rhoptries; no changes occur in posterior rhoptries. Lysosomes fuse with the par-asitophorous vacuole surrounding killed sporozoites but not live sporozoites. |
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Keywords: | Crystalloid body endodyogeny sporozoite penetration |
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