Trichonosema algonquinensis n. sp. (Phylum microsporidia) in Pectinatella magnifica (Bryozoa: phylactolaemata) from Algonquin Park, Ontario, Canada.

A new species of microsporidian, Trichonosema algonquinensis, is described from a freshwater bryozoan, Pectinatella magnifica from Ontario, Canada. The parasite develops in epithelial cells and appears as white, spherical masses throughout the tissues. Trichonosema algonquinensis is diplokaryotic, diploblastic and undergoes development in direct contact with the cytoplasm of the host cell.

Susceptibility of the domestic duck (Anas platyrhynchos) to experimental infection with Toxoplasma gondii oocysts.

A total of 28 domestic ducks were divided into seven groups of four ducks. Six groups were inoculated per os with 10(1), 10(2), 10(3), 10(4), 10(5) and 10(5.7) oocysts Toxoplasma gondii oocysts (K21 strain, which is avirulent for mice), and the remaining group was used as a control.

Calpain-1-dependent degradation of troponin I mutants found in familial hypertrophic cardiomyopathy.

The mechanism by which mutations of the cardiac troponin I (cTnI) gene evoke familial hypertrophic cardiomyopathy (fHCM) is unknown. In this investigation the potential effects of three fHCM-related cTnI mutations on Calpain-1-induced cTnI degradation were tested, and a study was made of whether additional conformational changes due to troponin complex formation and protein kinase A-induced phosphorylation affect the intensity of cTnI proteolysis. Purified recombinant wild-type cTnI and three of its fHCM-related missense mutants (R145G, G203S and K206Q), alone or in the troponin complex (i.

Phylogenetic position of the giant anuran trypanosomes Trypanosoma chattoni, Trypanosoma fallisi, Trypanosoma mega, Trypanosoma neveulemairei, and Trypanosoma ranarum inferred from 18S rRNA gene sequences.

Phylogenetic relationships within the kinetoplastid flagellates were inferred from comparisons of small-subunit ribosomal RNA gene sequences. These included 5 new gene sequences, Trypanosoma fallisi (2,239 bp), Trypanosoma chattoni (2,180 bp), Trypanosoma mega (2,211 bp), Trypanosoma neveulemairei (2,197 bp), and Trypanosoma ranarum (2,203 bp). Trees produced using maximum-parsimony and distance-matrix methods (least-squares, neighbor-joining, and maximum-likelihood), supported by strong bootstrap and quartet-puzzle analyses, indicated that the trypanosomes are a monophyletic group that divides into 2 major lineages, the salivarian trypanosomes and the nonsalivarian trypanosomes.

Redescription of Neospora caninum and its differentiation from related coccidia.

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.

The conceptual basis for a new classification of the coccidia.

At the joint meeting of the 8th International Coccidiosis Conference and the Annual Scientific Meeting of the Australian Society for Parasitology in Palm Cove, Australia, in July 2001, a Controversial Roundtable was held on 'New classification of coccidia'. The aim of this Roundtable was to stimulate and encourage discussion and debate on current classification schemes for the group of parasitic protozoa known as the eimeriid coccidia. In the past, such classifications have been based only on phenotypic characters such as morphology, ultrastructure, life cycles, and host specificity.

Chasing coccidia--new tools enter the race.

The 8th International Coccidiosis Conference, held on 9--13 July 2001 in Palm Cove, Australia, was a showcase of the latest studies on widely known coccidia, including Eimeria and Toxoplasma in addition to the emerging or re-emerging parasites such as Neospora, Cryptosporidium and Cyclospora. This meeting was staged in conjunction with the Annual Scientific Meeting of the Australian Society for Parasitology.

Molecular approaches for inferring evolutionary relationships among protistan parasites.

Within the diverse group of parasites broadly recognized as protists, there are limited morphological characters that can be used to distinguish species and even fewer characters that can infer evolutionary relationships among species. For this reason, molecular data are commonly used to infer relationships among species and strains. These studies most commonly rely on sequences associated with the ribosomal RNA genes but increasingly other nuclear, mitochondrial or plastid genes are contributing data.

Involvement of CD 8+ and CD 3+ lymphocytes in the transport of Eimeria necatrix sporozoites within the intestinal mucosa of chickens.

The phenotype of cells transporting sporozoites of Eimeria necatrix during a primary infection was determined using a panel of six monoclonal antibodies to various chicken lymphocyte surface markers. Sporozoites and cells harboring them were examined at 8, 12 and 18 h postinfection using two-color immunoflorescence and confocal microscopy. The majority of parasites observed within lymphocytes were found in CD 8 + (15%) or CD 3+ (13-22%) cells at all time periods examined.

Molecular phylogeny of the other tissue coccidia: Lankesterella and Caryospora.

Nearly complete sequences were obtained from the 18S rDNA genes of Eimeria falciformis (the type species of the genus), Caryospora bigenetica, and Lankesterella minima. Two clones of the rDNA gene from C. higenetica varied slightly in primary structure.

A comparison of sporozoite transport after homologous and heterologous challenge in chickens immunized with the Guelph strain or the Florida strain of Eimeria maxima.

The two strains of Eimeria maxima, Guelph and Florida, used in this study were previously shown to only partially cross-protect immunologically with respect to lesion scores, weight gains and feed conversions after heterologous challenge. In this paper, we provide evidence that this partial lack of cross-protection is manifested at the level of sporozoite transport. In birds immunized and challenged with the homologous strain, sporozoites accumulated in the lamina propria and were blocked from further movement into the crypts by 72 h post-challenge, unlike the situation observed in naive birds.

Partial characterization of a non-proteinaceous, low molecular weight antigen of Eimeria tenella.

A low molecular weight (LMW) antigen of Eimeria tenella, initially identified using a murine monoclonal antibody (mAb C(3)4F(1)) raised against E. tenella sporozoites, was partially characterized using enzymatic degradation. solvent extraction, and immunization into various inbred lines of mice.

Localization and immunogenicity of a low molecular weight antigen of Eimeria tenella.

A low molecular weight (LMW) antigen recognized by a murine monoclonal antibody (C(3)4F(1)) was localized within endogenous stages of Eimeria tenella (USDA strain 80). Using indirect fluorescent antibody assay and immunoelectron microscopy, the LMW antigen was found in: sporozoites, first, second and third generation meronts, gamonts, unsporulated oocysts, and sporocysts. The antigen was observed in the cytoplasm and pellicle of the parasite, and in the parasitophorous vacuole, sporocyst walls and cytoplasm of infected host cells.

Responses of chickens to a recombinant refractile body antigen of Eimeria tenella administered using various immunizing strategies.

A refractile body antigen (designated SO7') found in sporozoites of Eimeria tenella was administered to chickens in various immunizing forms to assess its ability to protect against virulent challenge. These included native antigen from the parasite (viable oocysts; per os), recombinant antigen (CheY-SO7'; s.c.

Genetic and antigenic evidence supports the separation of Hepatozoon canis and Hepatozoon americanum at the species level.

Recognition of Hepatozoon canis and Hepatozoon americanum as distinct species was supported by the results of Western immunoblotting of canine anti-H. canis and anti-H. americanum sera against H.

Cryptosporidium is more closely related to the gregarines than to coccidia as shown by phylogenetic analysis of apicomplexan parasites inferred using small-subunit ribosomal RNA gene sequences.

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 Ophriocystis elektroscirrha McLaughlin and Myers, 1970 (Neogregarinorida Grassé 1953). The sequences were aligned with several other gregarine and apicomplexan sequences from GenBank and the resulting data matrix analyzed by parsimony and maximum-likelihood methods.

Circadian blood pressure changes and cardiac abnormalities in IgA nephropathy.

The absence of diurnal blood pressure rhythm is characteristic of patients with chronic glomerulonephritis already before they develop hypertension. The prognostic importance and possible target organ-damaging effect of the absence are unknown. Simultaneously, 24-hour ambulatory blood pressure monitoring and echocardiographic investigations were done in 12 normotensive and 38 hypertensive IgA nephropathy patients.

An Eimeriid origin of isosporoid coccidia with Stieda bodies as shown by phylogenetic analysis of small subunit ribosomal RNA gene sequences.

Morphological and life cycle features of the tissue cyst-forming coccidia have been difficult to interpret in devising taxonomic classifications for the various genera. In this study, we amplified the full small subunit rRNA gene sequence of Isospora robini McQuistion and Holmes, 1988, and the partial sequence of Isospora gryphoni Olsen, Gissing, Barta, and Middleton, 1998 by PCR. Both of these species vary from Isospora species of mammals in having Stieda bodies on the sporocysts.

Plastids are widespread and ancient in parasites of the phylum Apicomplexa.

Current evidence supports the presence of a non-photosynthetic chloroplast-like organelle in several apicomplexan parasites, including Plasmodium falciparum and Toxoplasma gondii. This apicomplexan organelle, referred to here as the "plastid", may have been acquired through a primary or secondary endosymbiosis of a photosynthetic organism. Alternatively, apicomplexan plastids may have been acquired through several independent endosymbiotic events, as appears to be the case for the acquisition of chloroplasts by dinoflagellates.

Small subunit ribosomal RNA genes of tabanids and hippoboscids (Diptera: Brachycera): evolutionary relationships and comparison with other Diptera.

The small subunit ribosomal RNA (SSU rRNA) genes of hippoboscid (Ornithoica vicina Walker) and tabanid (Chrysops niger Macquart) Diptera were sequenced to determine their phylogenetic position within the order and to determine whether or not extensive hypervariable regions in this gene are widespread in the Diptera. A parsimony analysis of an alignment containing 8 dipteran sequences produced a single most parsimonious tree that placed O. vicina as sister group to Drosophila melanogaster Meigen.

Major histocompatibility complex class I- and II-deficient knock-out mice are resistant to primary but susceptible to secondary Eimeria papillata infections.

Two distinct mechanisms seem to function in reducing oocyst output during Eimeria papillata infections in mice. For naive mice, immunity was afforded by a T-cell-independent gamma-interferon (IFN-gamma) response mediated by natural killer (NK) cells. On reinfection, resistance was associated with T-cells and, to a lesser extent, perforin.