John Robert Barta

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This revision of the classification of unicellular eukaryotes updates that of Levine et al. (1980) for the protozoa and expands it to include other protists. Whereas the previous revision was primarily to incorporate the results of ultrastructural studies, this revision incorporates results from both ultrastructural research since 1980 and molecular(More)
Complete 18S ribosomal RNA gene sequences were determined for 8 Eimeria species of chickens and for Eimeria bovis of cattle. Sequences were aligned with each other and with sequences from 2 Sarcocystis spp., Toxoplasma gondii, Neospora caninum, and 4 Cryptosporidium spp. Aligned sequences were analyzed by maximum parsimony to infer evolutionary(More)
Investigating the evolutionary relationships of the major groups of Apicomplexa remains an important area of study. Morphological features and host-parasite relationships continue to be important in the systematics of the adeleorinid coccidia (suborder Adeleorina), but the systematics of these parasites have not been well-supported or have been constrained(More)
The phylogenetic placement of gregarine parasites (Apicomplexa: Gregarinasina) within the Apicomplexa was derived by comparison of small-subunit ribosomal RNA gene sequences. Gregarine sequences were obtained from Gregarina niphandrodes Clopton, Percival, and Janovy, 1991, and Monocystis agilis Stein, 1848 (Eugregarinorida Léger 1900), as well as from(More)
Partial (∼ 780 bp) mitochondrial cytochrome c oxidase subunit I (COI) and near complete nuclear 18S rDNA (∼ 1,780 bp) sequences were directly compared to assess their relative usefulness as markers for species identification and phylogenetic analysis of coccidian parasites (phylum Apicomplexa). Fifteen new COI partial sequences were obtained using two pairs(More)
Factors associated with immune-mediated protection against coccidial parasites were examined in a series of experiments utilizing immunocompromised scid/scid(SCID) and scid/scid.beige/beige(SCID/Bg) mice, as well as immunocompetent BALB/c mice. Number of oocysts produced per g feces each day and prepatent and patent periods were assessed for 4 eimerian(More)
Two laboratory strains (USDA strain No. 68 isolated from the eastern shore of Maryland 15 years ago and a University of Guelph strain isolated from an Ontario broiler house 23 years ago) and 3 recent field strains of Eimeria maxima [isolated in Maryland (MD), North Carolina (NC) and Florida (FL)] were tested for their ability to induce cross-protective(More)
During a 5 wk period beginning May 25, 1983, 329 amphibians, which included specimens of Rana catesbeiana Shaw, Rana clamitans Latreille, Rana septentrionalis Baird, Rana sylvatica LeConte, Hyla crucifer Wied, Bufo americanus Holbrook, and Plethodon cinereus Green, from Lake Sasajewun, Algonquin Park, Ontario, Canada were examined for blood parasites. The(More)
Neospora caninum is a protozoan parasite of animals, which before 1984 was misidentified as Toxoplasma gondii. Infection by this parasite is a major cause of abortion in cattle and causes paralysis in dogs. Since the original description of N. caninum in 1988, considerable progress has been made in the understanding of its life cycle, biology, genetics and(More)