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David A Morrison - One of the best experts on this subject based on the ideXlab platform.
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molecular phylogeny of besnoitia and the genetic relationships among besnoitia of cattle wildebeest and goats
Protist, 2000Co-Authors: John Ellis, Joakim O M Holmdahl, C Ryce, Peter A W Harper, John M Njenga, David A MorrisonAbstract:Summary Knowledge on parasites of the genus Besnoitia is sparse, which are classified in the subfamily Toxoplasmatinae of the phylum Apicomplexa. This arrangement hypotheses that Besnoitia represents the sister group to species such as Toxoplasma gondii and Hammondia hammondi . In order to test this hypothesis, phylogenetic analyses of 18S ribosomal DNA (rDNA) from Besnoitia, Hammondia, Isospora, Frenkelia, Eimeria, Neospora, Sarcocystis and Toxoplasma were performed. The 18S rDNA of Besnoitia besnoiti, Besnoitia jellisoni and Eimeria alabamensis were amplified by PCR and sequenced. Phylogenetic analyses by parsimony and maximum-likelihood methods showed Besnoitia to be reproducibly the sister group to a clade containing Hammondia, Neospora and Toxoplasma . Furthermore, Besnoitia of cattle, wildebeest and goats had identical ITS1 rDNA sequences, which questions the use of the taxon Besnoitia caprae to describe the Besnoitia found in goats.
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Effects of Sequence Alignment and Structural Domains of Ribosomal DNA on Phylogeny Reconstruction for the Protozoan Family Sarcocystidae
Molecular biology and evolution, 2000Co-Authors: N. B. Mugridge, David A Morrison, A M Tenter, T. Jäkel, A. R. Heckeroth, A. M. JohnsonAbstract:Finding correct species relationships using phylogeny reconstruction based on molecular data is dependent on several empirical and technical factors. These include the choice of DNA sequence from which phylogeny is to be inferred, the establishment of character homology within a sequence alignment, and the phylogeny algorithm used. Nevertheless, sequencing and phylogeny tools provide a way of testing certain hypotheses regarding the relationship among the organisms for which phenotypic characters demonstrate conflicting evolutionary information. The protozoan family Sarcocystidae is one such group for which molecular data have been applied phylogenetically to resolve questionable relationships. However, analyses carried out to date, particularly based on small-subunit ribosomal DNA, have not resolved all of the relationships within this family. Analysis of more than one gene is necessary in order to obtain a robust species signal, and some DNA sequences may not be appropriate in terms of their phylogenetic information content. With this in mind, we tested the informativeness of our chosen molecule, the large-subunit ribosomal DNA (lsu rDNA), by using subdivisions of the sequence in phylogenetic analysis through PAUP, fastDNAml, and neighbor joining. The segments of sequence applied correspond to areas of higher nucleotide variation in a secondary-structure alignment involving 21 taxa. We found that subdivision of the entire lsu rDNA is inappropriate for phylogenetic analysis of the Sarcocystidae. There are limited informative nucleotide sites in the lsu rDNA for certain clades, such as the one encompassing the subfamily Toxoplasmatinae. Consequently, the removal of any segment of the alignment compromises the final tree topology. We also tested the effect of using two different alignment procedures (CLUSTAL W and the structure alignment using DCSE) and three different tree-building methods on the final tree topology. This work shows that congruence between different methods in the formation of clades may be a feature of robust topology; however, a sequence alignment based on primary structure may not be comparing homologous nucleotides even though the expected topology is obtained. Our results support previous findings showing the paraphyly of the current genera Sarcocystis and Hammondia and again bring to question the relationships of Sarcocystis muris, Isospora felis, and Neospora caninum. In addition, results based on phylogenetic analysis of the structure alignment suggest that Sarcocystis zamani and Sarcocystis singaporensis, which have reptilian definitive hosts, are monophyletic with Sarcocystis species using mammalian definitive hosts if the genus Frenkelia is synonymized with Sarcocystis.
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the relationship of hammondia hammondi and sarcocystis mucosa to other heteroxenous cyst forming coccidia as inferred by phylogenetic analysis of the 18s ssu ribosomal dna sequence
Parasitology, 1999Co-Authors: Mark C Jenkins, C Ryce, Susan Liddell, Barry L. Munday, David A Morrison, John Ellis, J P DubeyAbstract:The complete sequence of the 18S small subunit (SSU) ribosomal DNA of Hammondia hammondi and Sarcocystis mucosa was obtained and compared to SSU rDNA sequences of Neospora caninum, Toxoplasma gondii, Besnoitia besnoiti, 2 species of Frenkelia, 3 species of Isospora, and 13 species of Sarcocystis. Analyses showed that H. hammondi and T. gondii are monophyletic and that these taxa shared a common ancestor with N. caninum and B. besnoiti. The weight of evidence shows that S. mucosa, S. neurona, and Frenkelia species form a clade thereby supporting the conclusion that Sarcocystis is paraphyletic.
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Phylogenetic relationships of the genus Frenkelia: a review of its history and new knowledge gained from comparison of large subunit ribosomal ribonucleic acid gene sequences
International journal for parasitology, 1999Co-Authors: N. B. Mugridge, David A Morrison, Jan Votýpka, Alan M. Johnson, Jitender P. Dubey, K. Luton, A M TenterAbstract:The diAerent genera currently classified into the family Sarcocystidae include parasites which are of significant medical, veterinary and economic importance. The genus Sarcocystis is the largest within the family Sarcocystidae and consists of species which infect a broad range of animals including mammals, birds and reptiles. Frenkelia, another genus within this family, consists of parasites that use rodents as intermediate hosts and birds of prey as definitive hosts. Both genera follow an almost identical pattern of life cycle, and their life cycle stages are morphologically very similar. However, the relationship between the two genera remains unresolved because previous analyses of phenotypic characters and of small subunit ribosomal ribonucleic acid gene sequences have questioned the validity of the genus Frenkelia or the monophyly of the genus Sarcocystis if Frenkelia was recognised as a valid genus. We therefore subjected the large subunit ribosomal ribonucleic acid gene sequences of representative taxa in these genera to phylogenetic analyses to ascertain a definitive relationship between the two genera. The full length large subunit ribosomal ribonucleic acid gene sequences obtained were aligned using Clustal W and Dedicated Comparative Sequence Editor secondary structure alignments. The Dedicated Comparative Sequence Editor alignment was then split into two data sets, one including helical regions, and one including non-helical regions, in order to determine the more informative sites. Subsequently, all four alignment data sets were subjected to diAerent tree-building algorithms. All of the analyses produced trees supporting the paraphyly of the genus Sarcocystis if Frenkelia was recognised as a valid genus and, thus, call for a revision of the current definition of these genera. However, an alternative, more parsimonious and more appropriate solution to the Sarcocystis/Frenkelia controversy is to synonymise the genus Frenkelia with the genus Sarcocystis. # 1999 Published by Elsevier Science Ltd on behalf of the Australian Society for Parasitology Inc. All rights reserved.
Jitender P. Dubey - One of the best experts on this subject based on the ideXlab platform.
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Frenkelia microti Infection in a Chinchilla (Chinchilla laniger) in the United States
Journal of Parasitology, 2000Co-Authors: Jitender P. Dubey, T. R. Clark, D. YantisAbstract:A Frenkelia microti tissue cyst was found in the brain of a chinchilla (Chinchilla laniger) used for biomedical research. This is the first report of Frenkelia infection in this animal in the United States.
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The taxonomic importance of obligate heteroxeny: distinction of Hammondia hammondi from Toxoplasma gondii – another opinion
Parasitology research, 2000Co-Authors: J K Frenkel, Jitender P. DubeyAbstract:We enumerate identical and divergent findings concerning the obligate heteroxenous Hammondia hammondi and the facultatively homoxenous or heteroxenous Toxoplasma gondii. Differences exist in life-cycles, transmission, and host range, especially transmissibility to birds and mammals other than rodents, in ultrastructural morphology, immunity and serology in cats and to lesser degree in rodents, in DNA sequences and in isoenzymes. Because the recognition of obligate heteroxeny is essential to study these organisms and to recognize them as taxa, it is advantageous to give heteroxeny a generic rather than a specific value. Characterization of organisms with the life-cycle patterns of Hammondia, Sarcocystis, Frenkelia, and Toxoplasma is best achieved by means of the genera presently used.
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Phylogenetic relationships of the genus Frenkelia: a review of its history and new knowledge gained from comparison of large subunit ribosomal ribonucleic acid gene sequences
International journal for parasitology, 1999Co-Authors: N. B. Mugridge, David A Morrison, Jan Votýpka, Alan M. Johnson, Jitender P. Dubey, K. Luton, A M TenterAbstract:The diAerent genera currently classified into the family Sarcocystidae include parasites which are of significant medical, veterinary and economic importance. The genus Sarcocystis is the largest within the family Sarcocystidae and consists of species which infect a broad range of animals including mammals, birds and reptiles. Frenkelia, another genus within this family, consists of parasites that use rodents as intermediate hosts and birds of prey as definitive hosts. Both genera follow an almost identical pattern of life cycle, and their life cycle stages are morphologically very similar. However, the relationship between the two genera remains unresolved because previous analyses of phenotypic characters and of small subunit ribosomal ribonucleic acid gene sequences have questioned the validity of the genus Frenkelia or the monophyly of the genus Sarcocystis if Frenkelia was recognised as a valid genus. We therefore subjected the large subunit ribosomal ribonucleic acid gene sequences of representative taxa in these genera to phylogenetic analyses to ascertain a definitive relationship between the two genera. The full length large subunit ribosomal ribonucleic acid gene sequences obtained were aligned using Clustal W and Dedicated Comparative Sequence Editor secondary structure alignments. The Dedicated Comparative Sequence Editor alignment was then split into two data sets, one including helical regions, and one including non-helical regions, in order to determine the more informative sites. Subsequently, all four alignment data sets were subjected to diAerent tree-building algorithms. All of the analyses produced trees supporting the paraphyly of the genus Sarcocystis if Frenkelia was recognised as a valid genus and, thus, call for a revision of the current definition of these genera. However, an alternative, more parsimonious and more appropriate solution to the Sarcocystis/Frenkelia controversy is to synonymise the genus Frenkelia with the genus Sarcocystis. # 1999 Published by Elsevier Science Ltd on behalf of the Australian Society for Parasitology Inc. All rights reserved.
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Detection of Neospora Caninum in Tissue Sections Using a Murine Monoclonal Antibody
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 1993Co-Authors: Rebecca A. Cole, Jitender P. Dubey, David S. Lindsay, Byron L. BlagburnAbstract:A murine monoclonal antibody (MAb 6G7), isotype IgG2a, produced against tachyzoites of Neospora caninum (isolate NC-l) reacted specifically with tachyzoites of N. caninum in an indirect immuno- fluorescent antibody test. MAb 6G7 did not react with tachyzoites of Toxoplasma gondii, sporozoites of Isospora suis, Eimeria bovis, or E. tenella, or merozoites of E. bovis in the indirect immunofluorescent antibody test. MAb 6G7 reacted positively with both tachyzoites and bradyzoites of N. caninum in an avidin-biotin peroxidase complex immunohistochemical test on formalin-fixed paraffin-embedded tissues. No reaction was observed with the following: tachyzoites and bradyzoites of T. gondii, T. gondii-like parasites, or Hammondia hammondi; bradyzoites of Frenkelia microti; schizonts and merozoites of Sarcocystis-like organisms; schizonts, sarcocysts, and oocysts/sporocysts of S. cruzi; schizonts and merozoites of S. canis; schizonts of S. hirsuta, S. tenella, and S. capracanis; merozoites of S. neurona and S. neurona-like organisms, E. bovis, or Haemoproteus sp.; bra- dyzoites and merozoites of S. montanaensis; bradyzoites of S. odocoileocanis, S. cruzi, and S. tenella; meronts, sexual stages, and caryocysts of Caryospora sp. and C. bigenetica; micromerozoites, macromerozoites, and schizonts of Hepatozoon canis; sporozoites, sexual stages, and oocysts of Cryptosporidium parvum and C. baileyi; trophozoites of Monocystis Zumbrici, Tritrichomonas foetus, and Balantidium coli; tissue cysts and bradyzoites of Besnoitia sp. and B. jellisoni; amastigotes of Leishmania sp.; and trophic theronts of Ichthyopthirius multifilis. MAb 6G7 reacted with tachyzoites and bradyzoites of N. caninum in natural and experimental infections in dogs, cattle, mice, rats, sheep, and goats, indicating that host origin of the tissues did not affect the performance of the test.
J K Frenkel - One of the best experts on this subject based on the ideXlab platform.
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determination of the genera of cyst forming coccidia
Parasitology Research, 2003Co-Authors: J K Frenkel, D. D. SmithAbstract:The following heteroxenous and cyst-forming coccidian genera, Besnoitia, Cystoisospora, Frenkelia, Hammondia, Neospora, Sarcocystis and Toxoplasma have been compared biologically, and a key to determine their tissue cysts is provided.
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The taxonomic importance of obligate heteroxeny: distinction of Hammondia hammondi from Toxoplasma gondii – another opinion
Parasitology research, 2000Co-Authors: J K Frenkel, Jitender P. DubeyAbstract:We enumerate identical and divergent findings concerning the obligate heteroxenous Hammondia hammondi and the facultatively homoxenous or heteroxenous Toxoplasma gondii. Differences exist in life-cycles, transmission, and host range, especially transmissibility to birds and mammals other than rodents, in ultrastructural morphology, immunity and serology in cats and to lesser degree in rodents, in DNA sequences and in isoenzymes. Because the recognition of obligate heteroxeny is essential to study these organisms and to recognize them as taxa, it is advantageous to give heteroxeny a generic rather than a specific value. Characterization of organisms with the life-cycle patterns of Hammondia, Sarcocystis, Frenkelia, and Toxoplasma is best achieved by means of the genera presently used.
Jaroslav Flegr - One of the best experts on this subject based on the ideXlab platform.
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free tree freeware program for construction of phylogenetic trees on the basis of distance data and bootstrap jackknife analysis of the tree robustness application in the rapd analysis of genus Frenkelia
Folia Biologica, 1999Co-Authors: A Pavlicek, S Hrda, Jaroslav FlegrAbstract:: The Win95 program for computation of distance matrixes and construction of phylogenetic or phenetic trees on the basis of RAPD, RFLP and allozyme data was presented. In contrast with other presently available software, the program FreeTree can also assess the robustness of the tree topology by bootstrap, jackknife or OTU-jackknife analysis. Moreover, the program can be used also for an analysis of data obtained in several independent experiments performed with nonidentical subsets of taxa. The function of the program was demonstrated by an analysis of RAPD data from 22 strains of Frenkelia. The program is available as an autoextractive archive containing the installation files of FreeTree and TreeView, manual in MS Word format and a sample of the input file at http://www.natur.cuni.cz/flegr/programs/+ ++freetree.
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Molecular phylogenetic relatedness of Frenkelia spp. (Protozoa, Apicomplexa) to Sarcocystis falcatula Stiles 1893: is the genus Sarcocystis paraphyletic?
The Journal of eukaryotic microbiology, 1998Co-Authors: Jan Votýpka, Václav Hypša, Milan Jirku, Jaroslav Flegr, Jiri Vavra, Julius LukešAbstract:The coccidians Frenkelia microti and F. glareoli (Apicomplexa: Sarcocystidae) form tissue cysts in the brain of small rodents (intermediate hosts) while oocysts are formed in the intestine of final hosts, buzzards of the genus Buteo. The inclusion of the small subunit ribosomal RNA gene sequences (SSU rRNA) of both Frenkelia species into the SSU rRNA trees of other, tissue cyst-forming coccidia strongly supports paraphyly of the genus Sarcocystis. Frenkelia spp. exhibit close relatedness to Sarcocystis falcatula Stiles 1893, a bird-opossum parasite, recognized under its junior synonym S. neurona Dubey et al. 1991, as the causative agent of equine protozoan myeloencephalitis on the American continent. As the definition of the genus Frenkelia is based on a plesiomorphic character (affinity to the neural tissue) of supposedly low phylogenetic value, the synonymization of the genus Frenkelia with Sarcocystis is proposed. This renders the genus Sarcocystis monophyletic.
Heikki Henttonen - One of the best experts on this subject based on the ideXlab platform.
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Parasite diversity of Norwegian lemmings (Lemmus lemmus)
Journal of Zoology, 2001Co-Authors: Juha Laakkonen, Voitto Haukisalmi, Jukka Niemimaa, Heikki HenttonenAbstract:The parasite diversity of Norwegian lemmings Lemmus lemmus was studied in northern Fennoscandia during a moderate population peak in 1997–98. Our aim was to study the parasites of lemmings in their normal mountainous habitats in anticipation of the next great lemming migration in northern Fennoscandia into the coniferous taiga. The blood parasites ( Hepatozoon , Trypanosoma and Bartonella ) found, Frenkelia sp., which invades the brain tissue of the host, and the pulmonary fungus Chrysosporium ( Emmonsia ) sp., have been detected previously in the Norwegian lemming, but an unknown fungus, and oocysts of Eimeria spp. have not been reported from L. lemmus before. The Norwegian lemming was found to have an exceptionally species-poor helminth fauna. Only one species of cestode ( Andrya sp.) occurring in lemmings at the adult stage was found, and the cestodes of carnivores that commonly parasitize voles at the larval stage were totally absent. The distribution and abundance of vectors, and sympatric definitive hosts of parasites are predicted to have a major role in determining the parasites that lemmings will encounter during their mass movements in new habitats. However, it is predicted that parasitism by adult and larval helminths is not markedly affected by the habitat change associated with the mass migration.
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Ultrastructure of Frenkelia sp. from a Norwegian Lemming in Finland
Journal of wildlife diseases, 2000Co-Authors: Juha Laakkonen, Heikki HenttonenAbstract:An apparently healthy Norwegian lemming (Lemmus lemmus) caught in northern Finland was observed to have a whitish body 0.5 to 1.0 mm in diameter in the external layer of the cerebral cortex. By light microscopy a highly lobulated cyst of Frenkelia sp. was observed. By transmission electron microscopy the cyst wall was seen consisting of a parasitophorous vacuolar membrane, an underlying electron-dense layer and a granular layer. The membrane was only slightly convoluted. The protrusions of the cyst wall appeared round but were often not distinctive. A very thin septum divided the interior of the cyst into compartments packed with bradyzoites and maturing zoites. The bradyzoites were elongate measuring 5–8 × 1.5–2 μm. This is the first electron microscopical study of Frenkelia sp. from L. lemmus.
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Disease patterns in field and bank vole populations during a cyclic decline in central Finland.
Comparative immunology microbiology and infectious diseases, 2000Co-Authors: Timo Soveri, Heikki Henttonen, Voitto Haukisalmi, E. Rudbäck, R. Schildt, R. Tanskanen, J. Husu-kallio, Antti Sukura, Juha LaakkonenAbstract:Abstract Declining field vole ( Microtus agrestis ) and bank vole ( Clethrionomys glareolus ) populations were sampled (117 field voles and 34 bank voles) in south-central Finland during the winter of 1988–89. The last surviving field voles were caught in April and bank voles in February. A subsample (16) of the April field voles were taken live to the laboratory for immunosuppression. The histopathology of the main internal organs and the presence of aerobic bacteria and certain parasites were studied. In the lungs, an increase in lymphoid tissue, probably caused by infections, was the most common finding (52% of all individuals). The prevalences in the voles, in the whole material, of Chrysosporium sp. and Pneumocystis carinii in lungs were 13 and 10% in field voles, and 9 and 0% in bank voles, respectively. Cysts of Taenia mustelae (9 and 27%) were the most common pathological changes in the liver. Enteritis was also rather common (14 and 34%). In field voles the prevalences of Frenkelia sp. in the brain and Sarcocystis sp. in leg muscles were low (both 6%). Bordetella bronchiseptica was commonly (31%) isolated from field vole lungs and Listeria monocytogenes from the intestines (34%). Salmonella spp. could not be found. The dynamics and abundance of inflammations in the lungs and intestines, as well as B. bronchiseptica isolations from the lungs, indicate that obvious epidemics took place in declining vole populations. Of the Luhanka subsample of 16 field voles brought to the laboratory in April, one died of listeriosis, two of Bordetella , and five died for unknown reasons. Even if small mustelids are the driving force in microtine cycles, it is possible that diseases also contribute to the decline.