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Jamie R. Stevens - One of the best experts on this subject based on the ideXlab platform.
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Trypanosoma rangeli is phylogenetically closer to old world trypanosomes than to Trypanosoma cruzi
International Journal for Parasitology, 2018Co-Authors: Oneida Espinosaalvarez, Patrick B. Hamilton, Paola A Ortiz, Luciana Lima, Andre G Costamartins, Myrna G Serrano, S Herder, Gregory A Buck, Erney P Camargo, Jamie R. StevensAbstract:Abstract Trypanosoma rangeli and Trypanosoma cruzi are generalist trypanosomes sharing a wide range of mammalian hosts; they are transmitted by triatomine bugs, and are the only trypanosomes infecting humans in the Neotropics. Their origins, phylogenetic relationships, and emergence as human parasites have long been subjects of interest. In the present study, taxon-rich analyses (20 trypanosome species from bats and terrestrial mammals) using ssrRNA, glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH), heat shock protein-70 (HSP70) and Spliced Leader RNA sequences, and multilocus phylogenetic analyses using 11 single copy genes from 15 selected trypanosomes, provide increased resolution of relationships between species and clades, strongly supporting two main sister lineages: lineage Schizotrypanum, comprising T. cruzi and bat-restricted trypanosomes, and Tra[Tve-Tco] formed by T. rangeli, Trypanosoma vespertilionis and Trypanosoma conorhini clades. Tve comprises European T. vespertilionis and African T. vespertilionis-like of bats and bat cimicids characterised in the present study and Trypanosoma sp. Hoch reported in monkeys and herein detected in bats. Tco included the triatomine-transmitted tropicopolitan T. conorhini from rats and the African NanDoum1 trypanosome of civet (carnivore). Consistent with their very close relationships, Tra[Tve-Tco] species shared highly similar Spliced Leader RNA structures that were highly divergent from those of Schizotrypanum. In a plausible evolutionary scenario, a bat trypanosome transmitted by cimicids gave origin to the deeply rooted Tra[Tve-Tco] and Schizotrypanum lineages, and bat trypanosomes of diverse genetic backgrounds jumped to new hosts. A long and independent evolutionary history of T. rangeli more related to Old World trypanosomes from bats, rats, monkeys and civets than to Schizotrypanum spp., and the adaptation of these distantly related trypanosomes to different niches of shared mammals and vectors, is consistent with the marked differences in transmission routes, life-cycles and host-parasite interactions, resulting in T. cruzi (but not T. rangeli) being pathogenic to humans.
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Classification and phylogeny of Trypanosoma cruzi
American Trypanosomiasis, 2010Co-Authors: Patrick B. Hamilton, Jamie R. StevensAbstract:Over the last 20 years our understanding of the evolutionary origin of Trypanosoma cruzi and other trypanosomes (genus Trypanosoma ) has advanced considerably through the application of molecular phylogenetic methods. Studies employing molecular tools have led to an improved understanding of trypanosome diversity in wildlife across several continents. Genetic methods have also resolved many of the evolutionary relationships among different trypanosome species and between the genus and related Trypanosomatid parasites. In combination with knowledge of continental drift and host phylogeography, this knowledge has been used to interpret the evolutionary history of many of these parasites. The most comprehensive studies at the level of the genus have used comparisons of sequences for 18S rRNA and glycosomal glyceraldehyde phosphate dehydrogenase ( gGAPDH ) genes. These studies now provide strong evidence that trypanosomes had a single origin (i.e., monophyletic) and that both Trypanosoma and Leishmania evolved vertebrate parasitism independently, and probably from separate monogenetic (single host) Trypanosomatid parasites of insects. Trypanosoma cruzi is only distantly related to Trypanosoma brucei , the agent of African human trypanosomiasis, and the two species acquired the ability to parasitize humans independently. T. cruzi falls within the “ T. cruzi clade,” together with trypanosomes from a wide range of mammals from both the Old and New Worlds and a number of species from bats. Evidence suggests that T. cruzi currently found in terrestrial mammals in the New World evolved from within a wider clade of bat trypanosomes. Studies of trypanosome biodiversity and evolution can have practical benefits: they can identify potential sources of novel pathogens, can facilitate the development of diagnostic tools, and can identify vectors and reservoirs of infection.
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Evolutionary rate differences in trypanosomes.
Infection Genetics and Evolution, 2001Co-Authors: Jamie R. Stevens, Andrew RambautAbstract:Ribosomal RNA-based studies of trypanosome phylogenies have highlighted considerable differences in genetic diversity within clades in the genus Trypanosoma and several-fold substitution rate differences between clades have been identified. While early 18S rRNA-based studies were hampered by highly variable substitution rates and long-branch attraction, it is apparent that genuine differences in evolution rates within localized clades do exist and questions remain regarding what rate or rates such clades are evolving at and why is the application of a single clock to trypanosome evolution so inappropriate? In this study, we explore rate heterogeneity in the commonly used 18S rRNA gene across genus Trypanosoma, using a maximum likelihood (ML) approach to explore local rate variations in clades of biological interest.
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the taxonomic position and evolutionary relationships of Trypanosoma rangeli
International Journal for Parasitology, 1999Co-Authors: Jamie R. Stevens, Marta M.g. Teixeira, Lewis E. H. Bingle, Wendy GibsonAbstract:This paper presents a re-evaluation of the taxonomic position and evolutionary relationships of Trypanosoma (Herpetosoma) rangeli based on the phylogenetic analysis of ssrRNA sequences of 64 Trypanosoma species and comparison of mini-exon sequences. All five isolates of T. rangeli grouped together in a clade containing Trypanosoma (Schizotrypanum) cruzi and a range of closely related trypanosome species from bats [Trypanosoma (Schizotrypanum) dionisii, Trypanosoma (Schizotrypanum) vespertilionis] and other South American mammals [Trypanosoma (Herpetosoma) leeuwenhoeki, Trypanosoma (Megatrypanum) minasense, Trypanosoma (Megatrypanum) conorhini] and an as yet unidentified species of trypanosome from an Australian kangaroo. Significantly T. rangeli failed to group with (a) species of subgenus Herpetosoma, other than those which are probably synonyms of T. rangeli, or (b) species transmitted via the salivarian route, although either of these outcomes would have been more consistent with the current taxonomic and biological status of T. rangeli. We propose that use of the names Herpetosoma and Megatrypanum should be discontinued, since these subgenera are clearly polyphyletic and lack evolutionary and taxonomic relevance. We hypothesise that T. rangeli and T. cruzi represent a group of mammalian trypanosomes which completed their early evolution and diversification in South America. # 1999 Australian Society for Parasitology. Published by Elsevier Science Ltd. All rights reserved.
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The taxonomic position and evolutionary relationships of Trypanosoma rangeli.
International Journal for Parasitology, 1999Co-Authors: Jamie R. Stevens, Marta M.g. Teixeira, Lewis E. H. Bingle, Wendy GibsonAbstract:This paper presents a re-evaluation of the taxonomic position and evolutionary relationships of Trypanosoma (Herpetosoma) rangeli based on the phylogenetic analysis of ssrRNA sequences of 64 Trypanosoma species and comparison of mini-exon sequences. All five isolates of T. rangeli grouped together in a clade containing Trypanosoma (Schizotrypanum) cruzi and a range of closely related trypanosome species from bats [Trypanosoma (Schizotrypanum) dionisii, Trypanosoma (Schizotrypanum) vespertilionis] and other South American mammals [Trypanosoma (Herpetosoma) leeuwenhoeki, Trypanosoma (Megatrypanum) minasense, Trypanosoma (Megatrypanum) conorhini] and an as yet unidentified species of trypanosome from an Australian kangaroo. Significantly T. rangeli failed to group with (a) species of subgenus Herpetosoma, other than those which are probably synonyms of T. rangeli, or (b) species transmitted via the salivarian route, although either of these outcomes would have been more consistent with the current taxonomic and biological status of T. rangeli. We propose that use of the names Herpetosoma and Megatrypanum should be discontinued, since these subgenera are clearly polyphyletic and lack evolutionary and taxonomic relevance. We hypothesise that T. rangeli and T. cruzi represent a group of mammalian trypanosomes which completed their early evolution and diversification in South America.
Wendy Gibson - One of the best experts on this subject based on the ideXlab platform.
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The origins of the trypanosome genome strains Trypanosoma brucei brucei TREU 927, T. b. gambiense DAL 972, T. vivax Y486 and T. congolense IL3000
Parasites & Vectors, 2012Co-Authors: Wendy GibsonAbstract:The genomes of several tsetse-transmitted African trypanosomes ( Trypanosoma brucei brucei, T. b. gambiense, T. vivax, T. congolense ) have been sequenced and are available to search online. The trypanosome strains chosen for the genome sequencing projects were selected because they had been well characterised in the laboratory, but all were isolated several decades ago. The purpose of this short review is to provide some background information on the origins and biological characterisation of these strains as a source of reference for future users of the genome data. With high throughput sequencing of many more trypanosome genomes in prospect, it is important to understand the phylogenetic relationships of the genome strains.
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Phylogenetic analysis reveals the presence of the Trypanosoma cruzi clade in African terrestrial mammals.
Infection Genetics and Evolution, 2008Co-Authors: Patrick B. Hamilton, Wendy Gibson, Er Adams, Flobert Njiokou, Gérard Cuny, Stéphane HerderAbstract:Despite the impact of some trypanosome species on human and livestock health, the full diversity of trypanosomes in Africa is poorly understood. A recent study examined the prevalence of trypanosomes among a wide variety of wild vertebrates in Cameroon using species-specific PCR tests, but six trypanosome isolates remained unidentified. Here they have been re-examined using fluorescent fragment length barcoding (FFLB) and phylogenetic analysis of glycosomal glyceraldehyde phosphate dehydrogenase gGAPDH and 18S ribosomal RNA (rDNA) genes. Isolates from a monkey (Cercopithecus nictitans) and a palm civet (Nandinia binotata) belonged to the Trypanosoma cruzi clade, known previously only from New World and Australian terrestrial mammals, and bats from Africa, Europe and South America. Of the four other isolates, three from antelope were identified as Trypanosoma theileri, and one from a crocodile as T. grayi. This is the first report of trypanosomes of the T. cruzi clade in African terrestrial mammals and expands the clade's known global distribution in terrestrial mammals. Previously it has been hypothesized that African and New World trypanosomes diverged after continental separation, dating the divergence to around 100 million years ago. The new evidence instead suggests that intercontinental transfer occurred well after this, possibly via bats or rodents, allowing these trypanosomes to establish and evolve in African terrestrial mammals, and questioning the validity of calibrating trypanosome molecular trees using continental separation.
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the taxonomic position and evolutionary relationships of Trypanosoma rangeli
International Journal for Parasitology, 1999Co-Authors: Jamie R. Stevens, Marta M.g. Teixeira, Lewis E. H. Bingle, Wendy GibsonAbstract:This paper presents a re-evaluation of the taxonomic position and evolutionary relationships of Trypanosoma (Herpetosoma) rangeli based on the phylogenetic analysis of ssrRNA sequences of 64 Trypanosoma species and comparison of mini-exon sequences. All five isolates of T. rangeli grouped together in a clade containing Trypanosoma (Schizotrypanum) cruzi and a range of closely related trypanosome species from bats [Trypanosoma (Schizotrypanum) dionisii, Trypanosoma (Schizotrypanum) vespertilionis] and other South American mammals [Trypanosoma (Herpetosoma) leeuwenhoeki, Trypanosoma (Megatrypanum) minasense, Trypanosoma (Megatrypanum) conorhini] and an as yet unidentified species of trypanosome from an Australian kangaroo. Significantly T. rangeli failed to group with (a) species of subgenus Herpetosoma, other than those which are probably synonyms of T. rangeli, or (b) species transmitted via the salivarian route, although either of these outcomes would have been more consistent with the current taxonomic and biological status of T. rangeli. We propose that use of the names Herpetosoma and Megatrypanum should be discontinued, since these subgenera are clearly polyphyletic and lack evolutionary and taxonomic relevance. We hypothesise that T. rangeli and T. cruzi represent a group of mammalian trypanosomes which completed their early evolution and diversification in South America. # 1999 Australian Society for Parasitology. Published by Elsevier Science Ltd. All rights reserved.
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The taxonomic position and evolutionary relationships of Trypanosoma rangeli.
International Journal for Parasitology, 1999Co-Authors: Jamie R. Stevens, Marta M.g. Teixeira, Lewis E. H. Bingle, Wendy GibsonAbstract:This paper presents a re-evaluation of the taxonomic position and evolutionary relationships of Trypanosoma (Herpetosoma) rangeli based on the phylogenetic analysis of ssrRNA sequences of 64 Trypanosoma species and comparison of mini-exon sequences. All five isolates of T. rangeli grouped together in a clade containing Trypanosoma (Schizotrypanum) cruzi and a range of closely related trypanosome species from bats [Trypanosoma (Schizotrypanum) dionisii, Trypanosoma (Schizotrypanum) vespertilionis] and other South American mammals [Trypanosoma (Herpetosoma) leeuwenhoeki, Trypanosoma (Megatrypanum) minasense, Trypanosoma (Megatrypanum) conorhini] and an as yet unidentified species of trypanosome from an Australian kangaroo. Significantly T. rangeli failed to group with (a) species of subgenus Herpetosoma, other than those which are probably synonyms of T. rangeli, or (b) species transmitted via the salivarian route, although either of these outcomes would have been more consistent with the current taxonomic and biological status of T. rangeli. We propose that use of the names Herpetosoma and Megatrypanum should be discontinued, since these subgenera are clearly polyphyletic and lack evolutionary and taxonomic relevance. We hypothesise that T. rangeli and T. cruzi represent a group of mammalian trypanosomes which completed their early evolution and diversification in South America.
Dennis J Grab - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms for the elimination of potentially lytic complement-fixing variable surface glycoprotein antibody-complexes inTrypanosoma brucei
Parasitology Research, 1994Co-Authors: D. C. W. Russo, D J L Williams, Dennis J GrabAbstract:Live antibody-coated Trypanosoma brucei parasites remove variable surface glycoprotein (VSG)-antibody complexes from their surface upon warming to 37° C and evade antibody-activated complement lysis by both protein synthesis-dependent and protein synthesis-independent mechanisms. The protein synthesis-dependent process follows antibody-mediated trypanosome agglutination, whereas the protein synthesis-independent mechanism can occur in the absence of trypanosome agglutination. The latter process leads to a more rapid climination of complement-fixing VSG-antibody complexes.
Donald S. Martin - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic position of the giant anuran trypanosomes Trypanosoma chattoni, Trypanosoma fallisi, Trypanosoma mega, Trypanosoma neveulemairei, and Trypanosoma ranarum inferred from 18S rRNA gene sequences.
The Journal of Parasitology, 2002Co-Authors: Donald S. Martin, André-denis G. Wright, John R. Barta, Sherwin S. DesserAbstract: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. The nonsalivarian trypanosomes further divide into 2 lineages, 1 containing trypanosomes of birds, mammals, and reptiles and the other containing trypanosomes of fish, reptiles, and anurans. Among the giant trypanosomes, T. chattoni is clearly shown to be distantly related to all the other anuran trypanosome species. Trypanosoma mega is closely associated with T. fallisi and T. ranarum, whereas T. neveulemairei and Trypanosoma rotatorium are sister taxa. The branching order of the anuran trypanosomes suggests that some toad trypanosomes may have evolved by host switching from frogs to toads.
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Trypanosoma CHATTONI, Trypanosoma FALLISI, Trypanosoma MEGA, Trypanosoma NEVEULEMAIREI, AND Trypanosoma RANARUM INFERRED FROM 18S rRNA GENE SEQUENCES
2002Co-Authors: Donald S. Martin, Andrd-denis G. Wright, John R. Bartat, Sherwin S. DessertAbstract:Phylogenetic relationships within the kinetoplastid flagellates were inferred from comparisons of small-subunit ri- bosomal 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. The nonsalivarian trypanosomes further divide into 2 lineages, I containing trypanosomes of birds, mammals, and reptiles and the other containing trypanosomes of fish, reptiles, and anurans. Among the giant trypanosomes, T. chattoni is clearly shown to be distantly related to all the other anuran trypanosome species. Trypanosoma mega is closely associated with T. fallisi and T. ranarum, whereas T. neveulemairei and Trypanosoma rotatorium are sister taxa. The branching order of the anuran trypanosomes suggests that some toad trypanosomes may have evolved by host switching from frogs to toads.
D. C. W. Russo - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms for the elimination of potentially lytic complement-fixing variable surface glycoprotein antibody-complexes inTrypanosoma brucei
Parasitology Research, 1994Co-Authors: D. C. W. Russo, D J L Williams, Dennis J GrabAbstract:Live antibody-coated Trypanosoma brucei parasites remove variable surface glycoprotein (VSG)-antibody complexes from their surface upon warming to 37° C and evade antibody-activated complement lysis by both protein synthesis-dependent and protein synthesis-independent mechanisms. The protein synthesis-dependent process follows antibody-mediated trypanosome agglutination, whereas the protein synthesis-independent mechanism can occur in the absence of trypanosome agglutination. The latter process leads to a more rapid climination of complement-fixing VSG-antibody complexes.
