Publications (7)12.84 Total impact
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Article: Trypanosoma (Megatrypanum) melophagium in the sheep ked Melophagus ovinus from organic farms in Croatia: phylogenetic inferences support restriction to sheep and sheep keds and close relationship with trypanosomes from other ruminant species.
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ABSTRACT: Trypanosoma (Megatrypanum) melophagium is a parasite of sheep transmitted by sheep keds, the sheep-restricted ectoparasite Melophagus ovinus (Diptera: Hippoboscidae). Sheep keds were 100% prevalent in sheep from five organic farms in Croatia, Southeastern Europe, whereas trypanosomes morphologically compatible with T. melophagium were 86% prevalent in the guts of the sheep keds. Multilocus phylogenetic analyses using sequences of small subunit rRNA, glycosomal glyceraldehyde-3-phosphate dehydrogenase, spliced leader, and internal transcribed spacer 1 of the rDNA distinguished T. melophagium from all allied trypanosomes from other ruminant species and placed the trypanosome in the subgenus Megatrypanum. Trypanosomes from sheep keds from Croatia and Scotland, the only available isolates for comparison, shared identical sequences. All biologic and phylogenetic inferences support the restriction of T. melophagium to sheep and, especially, to the sheep keds. The comparison of trypanosomes from sheep, cattle, and deer from the same country, which was never achieved before this work, strongly supported the host-restricted specificity of trypanosomes of the subgenus Megatrypanum. Our findings indicate that with the expansion of organic farms, both sheep keds and T. melophagium may re-emerge as parasitic infections of sheep.Journal of Eukaryotic Microbiology 12/2011; 59(2):134-44. · 2.66 Impact Factor -
Article: Multilocus phylogeographical analysis of Trypanosoma (Megatrypanum) genotypes from sympatric cattle and water buffalo populations supports evolutionary host constraint and close phylogenetic relationships with genotypes found in other ruminants.
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ABSTRACT: Species of the subgenus Trypanosoma (Megatrypanum) have been reported in cattle and other domestic and wild ruminants worldwide. A previous study in Brazil found at least four genotypes infecting cattle (Bos taurus), but only one in water buffalo (Bubalus bubalis). However, the small number of isolates examined from buffalo, all inhabiting nearby areas, has precluded evaluation of their diversity, host associations and geographical structure. To address these questions, we evaluated the genetic diversity and phylogeographical patterns of 25 isolates from water buffalo and 28 from cattle from four separate locations in Brazil and Venezuela. Multigene phylogenetic analyses of ssrRNA, internal transcribed spacer of rDNA (ITSrDNA), 5SrRNA, glycosomal glyceraldehyde 3-phosphate dehydrogenase (gGAPDH), mitochondrial cytochrome b (Cyt b), spliced leader (SL) and cathepsin L-like (CATL) sequences positioned all isolates from sympatric and allopatric buffalo populations into the highly homogeneous genotype TthIA, while the cattle isolates were assigned to three different genotypes, all distinct from TthIA. Polymorphisms in all of these sequences separated the trypanosomes infecting water buffalo, cattle, sheep, antelope and deer, and suggested that they correspond to separate species. Congruent phylogenies inferred with all genes indicated a predominant clonal structure of the genotypes. The multilocus analysis revealed one monophyletic assemblage formed exclusively by trypanosomes of ruminants, which corresponds to the subgenus T. (Megatrypanum). The high degree of host specificity, evidenced by genotypes exclusive to each ruminant species and lack of genotype shared by different host species, suggested that the evolutionary history of trypanosomes of this subgenus was strongly constrained by their ruminant hosts. However, incongruence between ruminant and trypanosome phylogenies did not support host-parasite co-evolution, indicating that host switches have occurred across ruminants followed by divergences, giving rise to new trypanosome genotypes adapted exclusively to one host species.International journal for parasitology 10/2011; 41(13-14):1385-96. · 3.39 Impact Factor -
Article: High genetic diversity in field isolates of Trypanosoma theileri assessed by analysis of cathepsin L-like sequences disclosed multiple and new genotypes infecting cattle in Thailand.
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ABSTRACT: In this study, we describe the first survey in Thailand of Trypanosoma theileri, a widespread and prevalent parasite of cattle that is transmitted by tabanid flies. Investigation of 210 bovine blood samples of Thai cattle from six farms by hematocrit centrifuge technique (HCT) revealed 14 samples with trypanosomes morphologically compatible to T. theileri. Additional animals were positive for T. theileri by PCR based on the Cathepsin L-like sequence (TthCATL-PCR) despite negative by HCT, indicating cryptic infections. Results revealed a prevalence of 26 ± 15% (95% CI) of T. theileri infection. Additionally, 12 samples positive for T. theileri were detected in cattle from other 11 farms. From a total of 30 blood samples positive by HCT and/or PCR from 17 farms, seven were characterized to evaluate the genetic polymorphism of T. theileri through sequence analysis of PCR-amplified CATL DNA sequences. All CATL sequences of T. theileri from Thai cattle clustered with sequences of the previously described phylogenetic lineages TthI and TthII, supporting only two major lineages of T. theileri in cattle around the world. However, 11 of the 29 CATL sequences analyzed showed to be different, disclosing an unexpectedly large polymorphic genetic repertoire, with multiple genotypes of T. theileri not previously described in other countries circulating in Thai cattle.Veterinary Parasitology 03/2011; 180(3-4):363-7. · 2.58 Impact Factor -
Article: Cysteine proteases of Trypanosoma (Megatrypanum) theileri: cathepsin L-like gene sequences as targets for phylogenetic analysis, genotyping diagnosis.
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ABSTRACT: Although Trypanosomatheileri and allied trypanosomes are the most widespread trypanosomes in bovids little is known about proteolytic enzymes in these species. We have characterized genes encoding for cathepsin L-like (CATL) cysteine proteases from isolates of cattle, water buffalo and deer that largely diverged from homologues of other trypanosome species. Analysis of 78 CATL catalytic domain sequences from 22 T. theileri trypanosomes disclosed 6 genotypes tightly clustered together into the T. theileri clade. The CATL genes in these trypanosomes are organized in tandem arrays of approximately 1.7kb located in 2 chromosomal bands of 600-720kb. A diagnostic PCR assay targeting CATL sequences detected T. theileri of all genotypes from cattle, buffaloes and cervids and also from tabanid vectors. Expression of T. theileri cysteine proteases was demonstrated by proteolytic activity in gelatin gels and hydrolysis of Z-Phe-Arg-AMC substrate. Results from this work agree with previous data using ribosomal and spliced leader genes demonstrating that CATL gene sequences are useful for diagnosis, population genotyping and evolutionary studies of T. theileri trypanosomes.Parasitology International 03/2010; 59(3):318-25. · 2.13 Impact Factor -
Article: Cathepsin L-like genes of Trypanosoma vivax from Africa and South America--characterization, relationships and diagnostic implications.
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ABSTRACT: We characterized sequences from genes encoding cathepsin L-like (CatL-like) cysteine proteases from African and South American isolates of Trypanosoma vivax and T. vivax-like organisms, and evaluated their suitability as genetic markers for population structure analysis and diagnosis. Phylogenetic analysis of sequences corresponding to CatL-like catalytic domains revealed substantial polymorphism, and clades of sequences (TviCatL1-9) were separated by large genetic distances. TviCatL1-4 sequences were from cattle isolates from West Africa (Nigeria and Burkina Faso) and South America (Brazil and Venezuela), which belonged to the same T. vivax genotype. T. vivax-like genotypes from East Africa showed divergent sequences, including TviCatL5-7 for isolates from Mozambique and TviCatL8-9 for an isolate from Kenya. Phylogenetic analysis of CatL-like gene data supported the relationships among trypanosome species reflected in the phylogenies based on the analysis of small subunit (SSU) of ribosomal RNA gene sequence data. The discovery of different CatL-like sequences for each genotype, defined previously by ribosomal DNA data, indicate that these sequences provide useful targets for epidemiological and population genetic studies. Regions in CatL-like sequences shared by all T. vivax genotypes but not by other trypanosomes allowed the establishment of a specific and sensitive diagnostic PCR for epidemiological studies in South America and Africa.Molecular and Cellular Probes 12/2008; 23(1):44-51. · 2.08 Impact Factor -
Article: Cathepsin L-like genes of Trypanosoma vivax from Africa and South America – characterization, relationships and diagnostic implications
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ABSTRACT: We characterized sequences from genes encoding cathepsin L-like (CatL-like) cysteine proteases from African and South American isolates of Trypanosoma vivax and T. vivax-like organisms, and evaluated their suitability as genetic markers for population structure analysis and diagnosis. Phylogenetic analysis of sequences corresponding to CatL-like catalytic domains revealed substantial polymorphism, and clades of sequences (TviCatL1–9) were separated by large genetic distances. TviCatL1–4 sequences were from cattle isolates from West Africa (Nigeria and Burkina Faso) and South America (Brazil and Venezuela), which belonged to the same T. vivax genotype. T. vivax-like genotypes from East Africa showed divergent sequences, including TviCatL5–7 for isolates from Mozambique and TviCatL8–9 for an isolate from Kenya. Phylogenetic analysis of CatL-like gene data supported the relationships among trypanosome species reflected in the phylogenies based on the analysis of small subunit (SSU) of ribosomal RNA gene sequence data. The discovery of different CatL-like sequences for each genotype, defined previously by ribosomal DNA data, indicate that these sequences provide useful targets for epidemiological and population genetic studies. Regions in CatL-like sequences shared by all T. vivax genotypes but not by other trypanosomes allowed the establishment of a specific and sensitive diagnostic PCR for epidemiological studies in South America and Africa.Molecular and Cellular Probes. -
Article: Cysteine proteases of Trypanosoma (Megatrypanum) theileri: Cathepsin L-like gene sequences as targets for phylogenetic analysis, genotyping diagnosis
[show abstract] [hide abstract]
ABSTRACT: Although Trypanosomatheileri and allied trypanosomes are the most widespread trypanosomes in bovids little is known about proteolytic enzymes in these species. We have characterized genes encoding for cathepsin L-like (CATL) cysteine proteases from isolates of cattle, water buffalo and deer that largely diverged from homologues of other trypanosome species. Analysis of 78 CATL catalytic domain sequences from 22 T. theileri trypanosomes disclosed 6 genotypes tightly clustered together into the T. theileri clade. The CATL genes in these trypanosomes are organized in tandem arrays of ∼ 1.7 kb located in 2 chromosomal bands of 600–720 kb. A diagnostic PCR assay targeting CATL sequences detected T. theileri of all genotypes from cattle, buffaloes and cervids and also from tabanid vectors. Expression of T. theileri cysteine proteases was demonstrated by proteolytic activity in gelatin gels and hydrolysis of Z-Phe-Arg-AMC substrate. Results from this work agree with previous data using ribosomal and spliced leader genes demonstrating that CATL gene sequences are useful for diagnosis, population genotyping and evolutionary studies of T. theileri trypanosomes.Parasitology International.
Top Journals
Institutions
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2011
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University of Zagreb
- Department of Parasitology and Parasitic Diseases with Clinic
Zagreb, Grad Zagreb, Croatia
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2010
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Universidade Cidade de São Paulo
São Paulo, Estado de Sao Paulo, Brazil
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2008
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Universidade de São Paulo
- Departamento de Parasitologia (ICB)
Ribeirão Preto, Estado de Sao Paulo, Brazil
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