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At least 19 recordsLinked to original sources

PubMed1991

Evolutionary relationships of avian Eimeria species among other Apicomplexan protozoa: monophyly of the apicomplexa is supported.

Direct, reverse transcriptase-mediated, partial sequencing of the small-subunit (16S-like) ribosomal RNA (srRNA) of Eimeria tenella and E. acervulina was performed. Sequences were aligned by eye with six previously published, partial or complete srRNA sequences of apicomplexan protists (Plasmodium berghei, Theileria annulata, Cryptosporidium sp., Toxoplasma gondii, Sarcocystis muris, and S. gigantea). Six eukaryotic protists (a slime mold, a yeast, two dinoflagellates, and two ciliates) acted as an outgroup for a parsimony-based phylogenetic analysis (PAUP Ver. 3.0). The 188 phylogenetically informative sites (i.e., those positions that neither were unvaried nor had only autapomorphic substitutions) supported a single tree topology 481 steps in length with a consistency index of 0.65 in which the monophyly of the Apicomplexa was supported. The two Eimeria species and S. muris, S. gigantea, and T. gondii formed a pair of monophyletic groups that were sister groups. The two Sarcocystis species were not hypothesized to be sister taxa. The genera Plasmodium and Cryptosporidium were hypothesized to form the sister group to these five coccidia and T. annulata. A priori data-editing techniques that deleted "variable" positions prior to analysis failed to recognize the monophyly of the Apicomplexa when the same parsimony-based tree-building algorithm was used. Inability of the outgroup taxa to root the well-supported ingroup tree (Apicomplexa) at a unique site when these taxa were used individually for this purpose reinforces the need for an appropriate, multiple-taxon outgroup in such analyses.

Animals↗

PubMed1979

Rhabdospora thelohani Laguessé, 1895 (Apicomplexa): new host and geographic records with taxonomic considerations.

New fish species and geographic records for Rhabdospora thelohani Laguessé, 1895 (rodlet cells) are presented. Additionally, the ultrastructure of R. thelohani in Alburnoides bipunctatus ohridanus Karaman, Borostomias antarcticus (Lönnberg), Leuciscus cephalus albus Bonaparte and Rutilus rubilio (Bonaparte) is compared with that reported by other authors and with members of Subphylum Apicomplexa. The ultrastructure of R. thelohani was similar in all the fish species examined; however, the organism was not present in all members of any single species and had intertissue density variations. Rhabdospora thelohani is pyriform, averaging in size 7 X 12 micrometer, with a basal nucleus. The surface complex is composed of a layer (0.5 micrometer diameter) formed by microfilaments (9.3 nm) and an outer trilaminar membrane (9.3 nm). The cytoplasm contains structures identical to rhoptries, micronemes and subpellicular microtubules. Mitochondria, Golgi apparatus, and rough endoplasmic reticulum were not observed, althouth free ribosomes were present and arranged in a vesicular pattern. The observations suggest that the organism moves between cell of epithelial layers and is either released into a lumen intact or passively or actively discharges its contents into a lumen. Results from this study indicate that R. thelohani should be considered a member of Apicomplexa unless definitive evidence is presented to the contrary.

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PubMedDate not supplied

Ascogregarina saraviae n. sp. (Apicomplexa: Lecudinidae) in Lutzomyia lichyi (Diptera: Psychodidae).

Ascogregarina saraviae n. sp. (Apicomplexa: Lecudinidae) is described from wild-caught Lutzomyia lichyi (Diptera: Psychodidae) females. Gametocysts adhered to the hemocoel side of the genital accessory gland walls and oocysts were injected into their lumina. Sporulated oocysts were ellipsoidal, 12.4 x 5.8 (11.6-13.1 x 5.6-5.9) micrometers, contained eight sporozoites and a refractile residuum. The elongate form of A. saraviae n. sp. oocysts, and their more delicate walls, clearly distinguish them from oocysts of A. chagasi (Adler & Mayrink, 1961).

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PubMed1992

The red-tailed hawk, Buteo jamaicensis, a native definitive host of Frenkelia microti (Apicomplexa) in North America.

Oral inoculation of prairie voles, Microtus ochrogaster, with coccidian sporocysts isolated from the feces of a red-tailed hawk, Buteo jamaicensis, in Kansas, USA, resulted in formation of Frenkelia microti (Apicomplexa: Sarcocystidae) tissue cysts in the brains of the voles. Five additional isolates of morphologically similar sporocysts collected from red-tailed hawks or other Buteo spp. in Kansas failed to result in detectable infections in rodents. These results are the first to verify that red-tailed hawks are natural definitive host in North America for F. microti.

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PubMed1987

Rapid nucleotide sequence analysis of the small subunit ribosomal RNA of Toxoplasma gondii: evolutionary implications for the Apicomplexa.

A method for obtaining a large proportion of the nucleotide sequence of the small subunit ribosomal RNA (srRNA) was applied to the obligate intracellular protozoon Toxoplasma gondii. The method uses reverse transcription of as little as 8 micrograms of total cellular RNA. This fast, efficient method has numerous advantages over traditional gene cloning methods when nucleotide sequences are required for evolutionary studies. A phylogenetic analysis of the srRNA sequence data showed that T. gondii is not especially closely related to any other organism for which srRNA sequences are available, including another member of the Apicomplexa.

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PubMed1991

The troublesome parasites--molecular and morphological evidence that Apicomplexa belong to the dinoflagellate-ciliate clade.

Large insertions and deletions in the variable regions of eukaryotic 16S-like rRNA relative to the archaebacterial structure have been defined as a marker for rapidly evolving taxa. Deletions in the rRNA occur in the diplomonad Giardia and the microsporidian Vairimorpha, whereas insertions occur in Euglenozoa (Euglena and the kinetoplastids), Acanthamoeba, Naegleria, Physarum, Dictyostelium, the apicomplexan Plasmodium, the ciliate Euplotes, and some metazoa. Except Acanthamoeba and Euplotes, all of these protists were previously placed at the base of the eukaryote phylogeny. A re-analysis of the 16S-like rRNA and 5S rRNA data with the neighborliness method revealed a close relationship of Apicomplexa to the dinoflagellate-ciliate clade, most probably closer to the dinoflagellates. Morphological evidence that supports this grouping is the layer of sacs underneath the plasma membrane in all three taxa and the identical structure of trichocysts in the apicomplexan Spiromonas and dinoflagellates. The remaining rapidly evolving organisms might still be misplaced in the 16S-like rRNA trees.

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PubMed1990

Fine structure of zoosporulation in Perkinsus atlanticus (Apicomplexa: Perkinsea).

Light and transmission electron microscopy were used to study different stages of Perkinsus atlanticus (Apicomplexa) during induced zoosporulation, with fluid thioglycollate medium and seawater. Cytokinesis and nucleokinesis of different developmental stages were studied every 12 h during the incubation period of 72 h, at which time the zoospores became free. Uninucleated and flagellated zoospores present the apical complex formed by conoid, polar ring, micronemes, rhoptries and subpellicular microtubules observed at different sections. Ultrastructural details were compared with the other two species of the genus Perkinsus.

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PubMed1987

Intestinal infections by Eimeria (s. l.) vanasi n. sp. (Eimeriidae, Apicomplexa, Protozoa) in cichlid fish.

Eimeria (s. l.) vanasi n. sp. is described from the intestine of a variety of cichlids in Israel and South Africa. Merogony and gamogony stages are both intra- and epiepithelial, Sporogony is exogenous with young zygotes being released from the fish in the faeces. Fully developed sporocysts are ellipsoid and apparently lacking both a Stieda body (characteristic of Eimeria s. st. and Epieimeria species) and a suture line (characteristic of Goussia species). In view of the present controversial generic status of piscine coccidia, the species is tentatively designated as Eimeria (s. l.) vanasi n. sp. (Eimeriidae, Apicomplexa, Protozoa).

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PubMed1986

Experimental transmission of Caryospora simplex (Apicomplexa: Eimeriidae) to Palestine vipers, Vipera xanthina palestinae (Serpentes: Viperidae).

Four littermate, laboratory-reared Palestine vipers, Vipera xanthina palestinae (#149, #150, #151, #152) (Serpentes: Viperidae) were used to determine modes by which Caryospora simplex (Apicomplexa: Eimeriidae) could be transmitted to snakes. Viper #149 was inoculated orally by stomach tube with 5.0 X 10(4) sporulated oocysts of C. simplex obtained from the feces of an Ottoman viper, V. x. xanthina and began passing unsporulated oocysts of C. simplex 121 days post-inoculation (DPI). Viper #150 was fed five mice that had been inoculated orally greater than or equal to 25 days previously with 5.0 X 10(4) sporulated oocysts of C. simplex and it began passing unsporulated oocysts of C. simplex 33 days after being fed the first two of five mice. Viper #151 was inoculated orally with sporulated oocysts of C. simplex obtained from viper #150 and began passing oocysts 52 DPI. Viper #152 served as an uninoculated control and did not pass oocysts of any species of coccidian. This study demonstrates that snake/snake and mouse/snake transmission of C. simplex readily occurs.

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PubMed1987

Two new species of coccidia (Apicomplexa: Eimeriidae) from Madagascar Gekkonids.

Two new species of coccidia (Apicomplexa: Eimeriidae) are described from the Madagascar giant day gecko, Phelsuma madagascariensis grandis, and the Golddust day gecko, P. laticauda. Both species of coccidia were found to infect the anterior one-half of the small intestine. Oocysts of Eimeria brygooi n. sp. are spherical or subspherical, 23.0 X 21.3 (18.8-25.2 X 16.4-23.2)micron; shape index (L/W) 1.1 (1.0-1.2). A micropyle, oocyst residuum, and polar granule are absent. Sporocysts are ovoid, 9.2 X 7.9 (8.0-10.0 X 7.2-8.8) micron; shape index 1.2 (1.0-1.3), with a Goussia-type suture; Stieda and substieda bodies are absent. A sporocyst residuum is present, 4.2 X 3.0 (3.2-6.4 X 2.4-4.0) micron. Sporozoites are elongate, with anterior and posterior refractile bodies. This coccidian was found to infect five of six (83%) P. m. grandis and one of five (20%) P. laticauda examined. Oocysts of Isospora gekkonis n. sp. are spherical or subspherical, 24.2 X 22.0 (21.6-26.4 X 20.0-23.6) micron; shape index 1.1 (1.0-1.2). A micropyle and oocyst residuum are absent; polar granule present. Sporocysts are ovoid, 12.2 X 9.4 (11.2-12.8 X 8.4-10.0) micron, with Stieda and substieda bodies; shape index 1.3 (1.2-1.4). A sporocyst residuum is present, either compact, 5.1 X 4.2 (4.0-7.2 X 3.2-5.6) micron or diffuse. Sporozoites are elongate, with anterior and posterior refractile bodies. Isospora gekkonis was found in two of six (33%) P. m. grandis and one of five (20%) P. laticauda. In addition, oocysts of Cryptosporidium sp. were found in the cloacas of two of six (33%) necropsied P. m. grandis.

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PubMed1988

Eimeria saudiensis n. sp. (Apicomplexa: Eimeriidae) from the Arabian oryx (Oryx leucoryx) in Saudi Arabia.

Oocysts of Eimeria saudiensis n. sp. (Apicomplexa: Eimeriidae) are described from the feces of the Arabian oryx, Oryx leucoryx, from the Riyadh Zoo, Saudi Arabia. The oocysts were ellipsoidal or slightly ovoid, 31.2 x 24.5 (24.3-36.5 x 20.0-27.6) micron with a bilayered wall about 1.7 micron thick. The micropyle was covered by a dome-shaped cap. The oocyst residuum was absent, but tiny polar granules were present. The sporocysts were elongate ovoid, 14.3 x 7.2 (11.5-18.5 x 6.0-9.0) micron, had a Stieda body, but lacked a substiedal body. The sporocyst residuum was present, composed of numerous small granules. The sporozoites were elongate club-shaped, and contained two prominent refractile bodies.

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PubMedDate not supplied

Isospora peromysci Davis, 1967 (Apicomplexa: Eimeriidae) in Peromyscus leucopus and P. maniculatus (Rodentia: Cricetidae) from Texas.

Oocysts of Isospora peromysci (Davis, 1967) (Apicomplexa: Eimeriidae) were recovered from the feces of 1/30 (3.3%) white-footed mice, Peromyscus leucopus, in Johnson County, Texas. This report represents a new host and geographic record for the parasite. The coccidium was also found in 1/20 (5.0%) deer mice, P. maniculatus, from the same locale. Morphological data are provided on the sporulated oocyst of I. peromysci and comparisons are made with previously published information on the species from other geographic localities.

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PubMedDate not supplied

Early development of Eimeria papillata (Apicomplexa: Eimeriidae) in the mouse.

Early development of Eimeria papillata (Apicomplexa) in the mouse was evaluated using Nomarski interference-contrast and brightfield microscopy. Sporozoite-shaped meronts, which were motile and contained a large posterior refractile body and a smaller anterior refractile body, were observed entering and leaving host cells in the jejunum of an experimentally infected mouse at 26 h post inoculation (HPI). However, early developmental stages were not observed in tissue of the duodenum, ileum, cecum and colon. The mean length and width of these meronts (n = 20) were 12.0 microns and 3.7 microns, respectively. Spherical or subspherical meronts containing crescent-shaped merozoites were observed at 36 HPI.

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PubMed1985

Lymphokine-induced inhibition of growth of Eimeria bovis and Eimeria papillata (Apicomplexa) in cultured bovine monocytes.

Sporozoites of Eimeria bovis penetrated and developed normally to first-generation meronts in bovine monocytes (BM) and Madin-Darby bovine kidney (MDBK) cells that had been pretreated with culture medium (CM) or supernatant (NS) from nonstimulated bovine T cells. At 240 h after sporozoite inoculation (ASI), the mean percent development (meronts/[sporozoites + meronts]) in CM- and NS-pretreated BM was 52 and 28%, respectively; values for MDBK cells were 36 and 35%, respectively. Pretreatment of BM and MDBK cells with supernatant (ConAS) from concanavalin A-stimulated bovine T cells had no effect on the ability of sporozoites to penetrate cells; however, at 240 h ASI, only 1% of the sporozoites in ConAS-pretreated BM cultures had developed to meronts. In contrast, ConAS had no adverse effect on the ability of E. bovis sporozoites to develop to first-generation meronts in MDBK cells. At 240 h ASI, E. bovis meronts in ConAS-pretreated BM were abnormal in appearance and retarded in development, whereas sporozoites appeared structurally normal by light microscopy. Pretreatment of BM with ConAS had no effect on the ability of sporozoites of Eimeria papillata (Apicomplexa) to penetrate cells. Sporozoites of E. papillata did not develop to meronts in ConAS-pretreated BM and, in contrast to E. bovis, most sporozoites were destroyed intracellularly.

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PubMed1989

Kinetics of murine delayed-type hypersensitivity response to Eimeria falciformis (Apicomplexa: Eimeriidae).

Mice recovering from a primary infection with an intestinal protozoan parasite, Eimeria falciformis (Apicomplexa: Eimeriidae), showed a classic delayed-type hypersensitivity (DTH) reaction to oocyst antigen challenge. This reaction was characterized by a biphasic pattern of footpad swelling. The first swelling peaked at 2 h after antigen challenge, whereas the second swelling peaked at 24 to 48 h after challenge. The DTH reaction was transferable with a T-cell-enriched spleen cell population from mice that had recovered from E. falciformis infection. Cytotoxic depletion of immune T cells with anti-L3T4 antibody and complement abrogated DTH transfer, indicating that L3T4-positive T cells were required. A T-cell-enriched spleen cell population from acutely infected mice suppressed the transfer of DTH with immune cells from recovered animals, implicating the existence of infection-induced immunoregulatory cells controlling the parasite-specific immune response during infection. Immune spleen cells also transferred resistance to infection as measured by oocyst production and death rate of recipients. Together, these results indicate that the DTH reaction, induced by infection with E. falciformis, is mediated by L3T4-positive T cells and is associated with resistance to infection.

Acute Disease↗

PubMed1987

Pathogenesis of infection with Sarcocystis rauschorum (Apicomplexa) in experimentally infected varying lemmings (Dicrostonyx richardsoni).

This study describes the sequential formation of lesions associated with the endogenous development of Sarcocystis rauschorum (Apicomplexa: Sarcocystidae) in varying lemmings, Dicrostonyx richardsoni. Lethal doses of sporocysts (greater than 500) were orally administered to lemmings examined 1-6 days postinoculation (DPI) whereas sublethal doses were administered to lemmings examined subsequently. Transient necrosis and purulent inflammation, in association with precystic merogony, occurred in the liver by 4.5 DPI, peaked at 6 DPI and subsided beginning at 11 DPI with the liver returning to normal by 15 DPI. Cyst formation in skeletal and cardiac muscle was associated with purulent inflammation and sarcolemmal proliferation beginning at 9 DPI. These lesions persisted to 42 DPI. In addition, multifocal nonsuppurative meningoencephalitis was present in six of 11 infected lemmings examined between 11 and 15 DPI.

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PubMed1990

Sarcocystis kirkpatricki n. sp. (Apicomplexa: Sarcocystidae) in muscles of raccoons (Procyon lotor) from Illinois.

Sarcocysts of Sarcocystis kirkpatricki n. sp. (Apicomplexa: Sarcocystidae) are described from the skeletal and heart musculature of 66 (66%) of 100 raccoons (Procyon lotor) from Illinois. Histologic examination of muscle tissues from tongue, diaphragm, esophagus, and heart revealed that 61%, 47%, 32%, and 2%, respectively, contained sarcocysts of this species. Juvenile raccoons (less than 1 yr old) were more likely (P less than 0.01) to have sarcocysts in the tissues examined (52/60 or 87%) than were adults (14/40 or 35%). Histologically, sarcocysts in the 4 tissues were similar: the cyst wall was 2-3 microns thick, PAS negative, and had fine hairlike surface projections; interior septa were indistinct. Ultrastructurally, sarcocyst walls had short (mean = 2.8 microns), straight to sloping, villuslike projections. Longitudinal tubular filaments inside these projections extended from the tips to the base, where they terminated in a granular electron-dense layer of the primary cyst wall. Thin septa were within the sarcocysts. Feeding experiments utilizing dogs and cats as potential definitive hosts were negative.

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PubMed1986

Immunoelectron microscopic demonstration of the exocytosis of dense granule contents into the secondary parasitophorous vacuole of Sarcocystis muris (Protozoa, Apicomplexa).

Merozoites of the parasitic protozoon Sarcocystis muris (Apicomplexa) possess three types of characteristic organelles with electron dense contents named rhoptries, micronemes, and dense granules, which are supposed to be involved in the parasite-host cell interactions during and after invasion. Dense granules were purified from a merozoite homogenate by centrifugation on a sucrose density gradient. It was shown by SDS polyacrylamide gel electrophoresis that they contain a major protein of 21 kDa. Polyclonal antibodies raised against this protein were applied to ultrathin frozen and Lowicryl-K4M-embedded sections of the parasite before and after host cell invasion. Dense granules were distinctly labeled by immunogold before and after invasion. After host cell invasion the parasite is enclosed in a secondary parasitophorous vacuole which contains an electron-dense material. This deposition was heavily labeled by anti 21 kDa antibodies which clearly demonstrated that the dense granule contents is released into the secondary parasitophorous vacuole.

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