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Sent on Wednesday, 2010 Feb 24Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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| PubMed Results |
| 1. | Parasitol Res. 2010 Feb 23. [Epub ahead of print]Phylogenetic position of the freshwater fish trypanosome, Trypanosoma ophiocephali (Kinetoplastida) inferred from the complete small subunit ribosomal RNA gene sequence.Gu Z, Wang J, Ke X, Liu Y, Liu X, Gong X, Li A.College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China. The complete small subunit rRNA (SSrRNA) gene sequence (2,142 nucleotides) of the freshwater fish trypanosome Trypanosoma ophiocephali Chen (1964) was determined. The phylogenetic analysis deduced using neighbor-joining, maximum parsimony, and Bayesian methods demonstrated the existence of an "aquatic clade". T. ophiocephali was revealed to be a member of the freshwater fish trypanosomes and form the sister species with Trypanosoma siniperca and Trypanosoma sp. Carpio with high bootstrap values (98% MP, 100% NJ, 100% Bay). The high similarity of SSrRNA gene sequences and morphometric characters showed that T. ophiocephali, T. siniperca and T. sp. Carpio probably were the same species. The phylogenetic trees further suggested that Chinese freshwater fish trypanosome might be paraphyletic, and fish trypanosomes should have low host specificity. |
| PMID: 20177907 [PubMed - as supplied by publisher] | |
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| 2. | Parasitol Res. 2010 Feb 23. [Epub ahead of print]A new experimental culture medium for cultivation of Leishmania amazonensis: its efficacy for the continuous in vitro growth and differentiatio n of infective promastigote forms.Rodrigues ID, Silva BA, Santos AL, Vermelho AB, Alviano CS, Rosa MD.Departamento de Microbiologia Geral, Instituto de Microbiologia Prof. Paulo de Góes (IMPPG), Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Bloco I, Ilha do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil. Parasites from the genus Leishmania cause a variety of disease states in humans and other mammals in tropical and subtropical regions, which include cutaneous, mucocutaneous and visceral leishmaniasis. The elaboration of a culture medium for the in vitro cultivation of Leishmania spp., which promotes the growth and differentiation of the parasites, is an important tool for diagnosis, biochemical, biological and immunological studies in the genus. Herein, we have reported the development of a rapid, inexpensive and reliable monophasic culture medium. The novel medium, designated PBHIL, promoted an excellent parasite growth, generating high quantities of promastigotes with long-term viability, and was able to induce cellular differentiation of L. amazonensis promastigotes to the amastigote-like forms (93%). Additionally, we reported the influence of this novel medium on the biochemical characteristics of L. amazonensis and on the interaction of this parasite parasites with mammalian macrophages. |
| PMID: 20177905 [PubMed - as supplied by publisher] | |
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| 3. | Indian J Pharmacol. 2009 Feb;41(1):32-5.Leishmanicidal activity of sap onins isolated from the leaves of Eclipta prostrata and Gymnema sylvestre.Khanna VG, Kannabiran K, Getti G.School of Biotechnology, Chemical and Biomedical Engineering, VIT University, Vellore, Tamil Nadu, India. OBJECTIVE: To evaluate the leishmanicidal activity of saponin, dasyscyphin C of Eclipta prostrata and sapogenin, gymnemagenol from Gymnema sylvestre leaves under in vitro conditions. MATERIALS AND METHODS: Dasyscyphin C/Gymnemagenol were dissolved in phosphate buffered saline (PBS) and diluted with liquid medium to obtain concentrations ranging from 1000 to 15 mug /ml. The leishmanicidal activity against leishmanial parasites, Leishmania major, Leishmania aethiopica and Leishmania tropica promastigotes was studied by the MTS assay. RESULT: The Dasyscyphin C isolated from E. prostrata showed good leishmanicidal activity at 1000mug/ml concentration, with the IC(50) value of 450mug/ml against L. major promastigote and the percentage of parasitic death was 73; whereas, gymnemagenol of G. sylvestre showed only 52% parasitic death at 1000 mug/ml concentration. The other Leishmania species, L. aethiopica and L. tropica promastigotes, were less sensitive to the saponins of E. prostrata and G. sylvestre. CONCLUSION: From this study, it can be concluded that the dasyscyphin C of E. prostrata has significant leishmanicidal activity against L. major promastigote. |
| PMID: 20177579 [PubMed - in process] | |
| 4. | Vet Parasitol. 2010 Feb 4. [Epub ahead of print]Distribution of Phlebotomus perniciosus in North-Italy: A study on 18S rDNA of phlebotomine sand flies.Ferroglio E, Romano A, Dettoni F, Trisciuoglio A.Dipartimento di Produzioni Animali, Epidemiologia ed Ecologia, Università di Torino, Via L. Da Vinci 44, 10095 Grugliasco, TO, Italy. Leishmaniasis has recently spread, and is now endemic, in many parts of North Italy, even if it is not clear how sand flies vectors have reached this area. In order to clarify the origin of the Phlebotomus perniciosus, the main sand flies specie found in these areas, we analyzed and compared the 18S rDNA sequence from 33 out of 122 P. perniciosus collected in new endemic areas, from neighbor (</=120km) traditionally endemic area (Liguria) and from an area about 400km far from the North West Italy. Based on the 18S rDNA sequence analysis, three different groups with different degrees of heterogeneity were identified. Two of them are suggestive of migration at a local scale and one, found in all sampled foci, is probably due to passive carriage. Results suggest that both migration on small scale from traditionally endemic area and passive carriage on long distance can contribute to sand flies colonization of new areas. Copyright © 2010 Elsevier B.V. All rights reserved. |
| PMID: 20176442 [PubMed - as supplied by publisher] | |
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| 5. | BMC Genomics. 2010 Feb 22;11(1):124. [Epub ahead of print]Digital gene expression analysis of two life cycle stages of the human-infective parasite, Trypanosoma brucei gambiense reveals differentially expressed clusters of co-regulated genes.Veitch NJ, Johnson PC, Trivedi U, Terry S, Wildridge D, Macleod A.ABSTRACT: BACKGROUND: The evolutionarily ancient parasite, Trypanosoma brucei, is unusual in that the majority of its genes are regulated post-transcriptionally, leading to the suggestion that transcript abundance of most genes does not vary significantly between different life cycle stages despite the fact that the parasites undergo substantial cellular remodelling and metabolic changes throughout its complex life cycle. To investigate this in the clinically relevant sub-species, Trypanosoma brucei gambiense, which is the causative agent of the fatal human disease African sleeping sickness, we have compared the transcriptome of two different life cycle stages, the potentially human-infective bloodstream forms with the non-human-infective procyclic stage using digital gene expression (DGE) analysis. RESULTS: Over eleven million unique tags were generated, producing expression data for 7360 genes, covering 81% of the genes in the genome. Compared to microarray analysis of the related T. b. brucei parasite, approximately 10 times more genes with a 2.5 fold change in expression levels were detected. The transcriptome analysis revealed the existence of several differentially expressed gene clusters within the genome, indicating that contiguous genes presumably from the same polycistronic unit are co-regulated either at the level of transcription or transcript stability. CONCLUSIONS: DGE analysis is extremely sensitive for detecting gene expression differences, revealing firstly that a far greater number of genes are stage-regulated than had previously been identified and secondly and more importantly, this analysis has revealed the existence of several differentially expressed clusters of genes present on what appears to be the same polycistronic units, a phenomenon which had not previously been observed in microarray studies. These differentially regulated clusters of genes are in addition to the previously identified RNA polymerase I polycistronic units of variant surface glycoproteins and procyclin expression sites, which encode the major surface proteins of the parasite. This raises a number of questions regarding the function and regulation of the gene clusters that clearly warrant further study. |
| PMID: 20175885 [PubMed - as supplied by publisher] | |
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| 6. | PLoS Negl Trop Dis. 2009 Dec 22;3(12):e571.Maternal infection with Trypanosoma cruzi and congenital Chagas disease induce a trend to a type 1 polarization of infant immune responses to vaccines.Dauby N, Alonso-Vega C, Suarez E, Flores A, Hermann E, Córdova M, Tellez T, Torrico F, Truyens C, Carlier Y.Laboratoire de Parasitologie, Faculté de Médecine, Université Libre de Bruxelles (ULB), Brussels, Belgium. BACKGROUND: We previously showed that newborns congenitally infected with Trypanosoma cruzi (M+B+) display a strong type 1 parasite-specific T cell immune response, whereas uninfected newborns from T. cruzi-infected mothers (M+B-) are prone to produce higher levels of proinflammatory cytokines than control neonates (M-B-). The purpose of the present study was to determine if such fetal/neonatal immunological environments could alter the response to standard vaccines administered in early life. METHODOLOGY: Infants (6-7 months old) living in Bolivia, an area highly endemic for T. cruzi infection, and having received Bacillus Calmette Guerin (BCG), hepatitis B virus (HBV), diphtheria and tetanus vaccines, were enrolled into the M+B+, M+B-, M-B- groups mentioned above. The production of IFN-gamma and IL-13, as markers of Th1 and Th2 responses respectively, by peripherical blood mononuclear cells stimulated with tuberculin purified protein derivative of Mycobacterium tuberculosis (PPD) or the vaccinal antigens HBs, diphtheria toxoid (DT) or tetanus toxoid (TT), as well as circulating levels of IgG antibodies against HBsAg, DT and TT were analyzed in infants. Cellular responses to the superantigen SEB were also monitored in M+B+, M+B-, M-B-infants and newborns. PRINCIPAL FINDINGS: M+B+ infants developed a stronger IFN-gamma response to hepatitis B, diphtheria and tetanus vaccines than did M+B- and M-B- groups. They also displayed an enhanced antibody production to HBsAg. This was associated with a type 1-biased immune environment at birth, since cells of M+B+ newborns produced higher IFN-gamma levels in response to SEB. M+B- infants produced more IFN-gamma in response to PPD than the other groups. IL-13 production remained low and similar in all the three groups, whatever the subject's ages or vaccine status. CONCLUSION: These results show that: i) both maternal infection with T. cruzi and congenital Chagas disease do not interfere with responses to BCG, hepatitis B, diphtheria and tetanus vaccines in the neonatal period, and ii) the overcoming of immunological immaturity by T. cruzi infection in early life is not limited to the development of parasite-specific immune responses, but also tends to favour type 1 immune responses to vaccinal antigens. PMCID: PMC2796860 |
| PMID: 20041029 [PubMed - indexed for MEDLINE] | |
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| 7. | Infect Genet Evol. 2009 Dec;9(6):1345-51. Epub 2009 Sep 26.Identification of a large hybrid zone between sympatric sibling species of Triatoma dimidiata in the Yucatan peninsula, Mexico, and its epidemiological importance.Herrera-Aguilar M, Be-Barragán LA, Ramirez-Sierra MJ, Tripet F, Dorn P, Dumonteil E.Laboratorio de Parasitología, Centro de Investigaciones Regionales Dr Hideyo Noguchi, Universidad Autónoma de Yucatán, Mérida, Yucatan, Mexico. Triatoma dimidiata is one of the major Chagas disease vectors, with an extensive diversity in its morphology, habitat, and level of domiciliation. Molecular studies based on the internal transcribed spacer 2 (ITS-2) have subdivided this species into four potential taxonomic groups. Using both ITS-2 and cytochrome B markers, we confirmed the sibling species status of ITS-2 Group 3 and detected an apparent sympatry of ITS-2 Groups 2 and 3 in the Yucatan peninsula, Mexico. Here we examine the geographic distribution of T. dimidiata ITS-2 genotypes in the region and compare their egg production and Trypanosoma cruzi infection rates, as indicators of biological differences between groups. PCR genotyping of large natural populations showed an extensive sympatry of Groups 2 and 3 in most of the peninsula, often within the same house. We also detected a large proportion of individuals displaying ITS-2 sequences from both Groups 2 and 3, suggesting hybridization. Analysis of ITS-2 genotype frequencies indicated a strong departure from Hardy-Weinberg equilibrium in female hybrids, but not in males, due to a large heterozygote deficit. These results suggest random mating between ITS-2 Groups 2 and 3 combined with reduced viability and/or survival in female hybrids. This and other factors may allow for the maintenance of distinct ITS-2 Groups 2 and 3 populations despite high hybrid frequencies. Importantly, T. cruzi infection was much higher in hybrids compared to ITS-2 Groups 2 and 3 individuals, but all three genotypes appeared to seasonally infest houses in a similar manner in the region. These findings warrant further studies on T. dimidiata taxonomy and its epidemiologic implications. |
| PMID: 19786121 [PubMed - indexed for MEDLINE] | |
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| 8. | Infect Genet Evol. 2009 Dec;9(6):1306-10. Epub 2009 Sep 22.Trypanosoma rangeli genotypes association with Rhodnius prolixus and R. pallescens allopatric distribution in Central America.Salazar-Antón F, Urrea DA, Guhl F, Arévalo C, Azofeifa G, Urbina A, Blandón-Naranjo M, Sousa OE, Zeledón R, Vallejo GA.Zoonosis Laboratory, School of Veterinary Medicine, Universidad Nacional, Heredia, Costa Rica. Previous kDNA polymorphism-based reports have revealed the existence of two Trypanosoma rangeli genotypes (KP1+ and KP1-): SL and SSU rRNA gene polymorphism-based studies have revealed that five genotypes (A-E) are distributed throughout different Latin-American countries. Some evidence has shown that the genotypes' biogeographical distribution is associated with sympatric Rhodnius species. 12 T. rangeli isolates from humans and reservoirs from El Salvador, Guatemala, Honduras, Costa Rica and Panama were characterised by kDNA and mini-exon gene intergene spacer analysis and compared to 12 previously characterised isolates from humans and vectors from Colombia, Guatemala, Honduras and Venezuela. Central American isolates corresponded to genotypes called KP1(+) or lineage A and KP1(-) or lineage C. Such dimorphism was corroborated by randomly amplified polymorphic DNA (RAPD) in 22 selected isolates; a dendrogram was thus produced having two defined branches. One branch grouped KP1(-) or lineage C strains isolated from Rhodnius colombiensis (Colombia), humans (Panama), Procyon lotor and Choloepus hoffmanni (Costa Rica). The other group was formed by KP1(+) or lineage A strains isolated from Rhodnius prolixus (Colombia, Venezuela) and humans (El Salvador, Guatemala, Honduras). These results present evidence that both groups infect different mammals (humans, domestic and silvatic animals) having no association with any particular vertebrate species; however, T. rangeli KP1(+) or (A) strains have been isolated in Central America in areas where R. prolixus circulate (Honduras, El Salvador and Guatemala) and KP1(-) or (C) strains have been isolated in areas where Rhodnius pallescens is the main vector (Panama and Costa Rica) indicating a parasite-vector association. The same lineages circulate in Andean countries (Colombia, Venezuela, Ecuador and Peru), KP1+ being associated with members of the prolixus group (R. prolixus and Rhodnius robustus) and KP1- with members of the pallescens group (R. pallescens, R. colombiensis and Rhodnius ecuadoriensis). |
| PMID: 19778637 [PubMed - indexed for MEDLINE] | |
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| 9. | Cell Microbiol. 2009 Dec;11(12):1724-34. Epub 2009 Sep 14.Antigenic variation in the African trypanosome: molecular mechanisms and phenotypic complexity.Morrison LJ, Marcello L, McCulloch R.University of Glasgow, Wellcome Centre for Molecular Parasitology and Division of Infection and Immunity, Glasgow Biomedical Research Centre, 120 University Place, Glasgow, G12 8TA, UK. Antigenic variation is an immune evasion strategy that has evolved in viral, bacterial and protistan pathogens. In the African trypanosome this involves stochastic switches in the composition of a variant surface glycoprotein (VSG) coat, using a massive archive of silent VSG genes to change the identity of the single VSG expressed at a time. VSG switching is driven primarily by recombination reactions that move silent VSGs into specialized expression sites, though transcription-based switching can also occur. Here we discuss what is being revealed about the machinery that underlies these switching mechanisms, including what parallels can be drawn with other pathogens. In addition, we discuss how such switching reactions act in a hierarchy and contribute to pathogen survival in the face of immune attack, including the establishment and maintenance of chronic infections, leading to host-host transmission. |
| PMID: 19751359 [PubMed - indexed for MEDLINE] | |
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| 10. | Infect Genet Evol. 2009 Dec;9(6):1301-5. Epub 2009 Aug 5.Molecular detection of trypanosomes in cattle in South America and genetic diversity of Trypanosoma evansi based on expression-site-associated gene 6.Mekata H, Konnai S, Witola WH, Inoue N, Onuma M, Ohashi K.Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan. In South American countries, trypanosomiasis as a result of Trypanosoma evansi and Trypanosoma vivax infections causes significant economic losses in livestock. The objectives of this study were to characterize the epidemiology of bovine trypanosomiasis in South America and to draw a comparison between South American and Asian T. evansi isolates based on the polymorphisms in their transferrin receptor encoding gene 6. We assessed the prevalence rates of T. evansi and T. vivax infections in cattle in different regions of Peru and Bolivia using the polymerase chain reaction (PCR) and found that, in Lima and Pucallpa in the Republic of Peru, T. evansi infection rates were 5.8% (6/104) and 2.5% (5/195), respectively, while in Santa Cruz, Republic of Bolivia, the infection rate for T. evansi was 11.5% (59/510). The prevalence rates of T. vivax in Lima and Santa Cruz were 3.8% (4/104) and 0.9% (5/510), respectively. In T. evansi, uptake of host transferrin is mediated by a receptor derived from the two expression site-associated genes 6 and 7 (ESAG6 and ESAG7). We previously showed that the ESAG6 depicts genetic diversity among different isolates of T. evansi in Asia. In this study, we cloned and sequenced the ESAG6 genes from T. evansi isolates from South America, and found, in addition to some of the previously observed variants, 20 novel variants of ESAG6 genes which could be categorized into three new clades among the various isolates. To conclude, the results obtained in this study suggest that T. evansi isolates from South America are more diverse than the Asian isolates. |
| PMID: 19664722 [PubMed - indexed for MEDLINE] | |
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