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Wen YZ, Tang HT, Cai XL, Wu N, Xu JZ, Su BX, Hide G, Lun ZR, Lai DH. PAG3 promotes the differentiation of bloodstream forms in Trypanosoma brucei and reveals the evolutionary relationship among the Trypanozoon trypanosomes. Front Cell Infect Microbiol 2022. [DOI: 10.3389/fcimb.2022.1021332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
IntroductionTrypanosoma brucei, T. evansi and T. equiperdum are members of the subgenus Trypanozoon and are highly similar morphologically and genetically. The main differences between these three species are their differentiation patterns in the hosts and the role of vectors in their life cycles. However, the mechanisms causing these differences are still controversial.MethodsPAG3 gene was accessed by PCR amplification in 26 strains of Trypanozoon and sequences were then analyzed by BLAST accompanied with T. evansitype B group. RNA interference and CRISPR/Cas9 were used for revealing possible role of PAG3 in slender to stumpy transformation.ResultsThe procyclin associated gene 3 (PAG3) can be found in the pleomorphicspecies, T.brucei, which undergoes differentiation of slender forms to the stumpy form. This differentiation process is crucial for transmission to the tsetse fly vector. However, a homologue of PAG3 was not detected in either T. evansi or in the majority of T. equiperdum strains which are allmonomorphic. Furthere xperiments in T. brucei demonstrated that, when PAG3 was down-regulated or absent, there was a significant reduction in the differentiation from slender to stumpy forms.ConclusionTherefore, we conclude that PAG3 is a key nuclear gene involved in the slender to stumpy differentiation pathway of T.brucei in the mammalian host. Loss of this gene might also offer a simple evolutionary mechanism explaining why T. evansi and some T. equiperdum have lost the ability to differentiate and have been driven to adapt to transmission cycles that by pass the tsetse vector or mechanical contact.
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A novel metabarcoded deep amplicon sequencing tool for disease surveillance and determining the species composition of Trypanosoma in cattle and other farm animals. Acta Trop 2022; 230:106416. [PMID: 35317999 DOI: 10.1016/j.actatropica.2022.106416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 11/21/2022]
Abstract
The World Health Organization (WHO) and the Food and Agriculture Organization (FAO) have developed strategies to control trypanosomiasis in humans and livestock in endemic areas. These require a better understanding of the distribution of different Trypanosoma species and improved predictions of where they might appear in the future, based on accurate diagnosis and robust surveillance systems. Here, we describe a metabarcoding deep amplicon sequencing method to identify and determine the Trypanosoma species in co-infecting communities. First, four morphological verified Trypanosoma species (T. brucei, T. congolense, T. vivax and T. theileri) were used to prepare test DNA pools derived from different numbers of parasites to evaluate the method's detection threshold for each of the four species and to assess the accuracy of their proportional quantification. Having demonstrated the accurate determination of species composition in Trypanosoma communities, the method was applied to determine its detection threshold using blood samples collected from cattle with confirmed Trypanosoma infections based on a PCR assay. Each sample showed a different Trypanosoma species composition based on the proportion of MiSeq reads. Finally, we applied the assay to field samples to develop new insight into the species composition of Trypanosoma communities in cattle, camels, buffalo, horses, sheep, and goat in endemically infected regions of Pakistan. We confirmed that Trypanosoma evansi is the major species in Pakistan and for the first time showed the presence of Trypanosoma theileri. The metabarcoding deep amplicon sequencing method and bioinformatics pathway have several potential applications in animal and human research, including evaluation of drug treatment responses, understanding of the emergence and spread of drug resistance, and description of species interactions during co-infections and determination of host and geographic distribution of trypanosomiasis in humans and livestock.
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Wen YZ, Lun ZR, Zhu XQ, Hide G, Lai DH. Further evidence from SSCP and ITS DNA sequencing support Trypanosoma evansi and Trypanosoma equiperdum as subspecies or even strains of Trypanosoma brucei. INFECTION GENETICS AND EVOLUTION 2016; 41:56-62. [PMID: 27016375 DOI: 10.1016/j.meegid.2016.03.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/17/2016] [Accepted: 03/21/2016] [Indexed: 10/22/2022]
Abstract
The subgenus Trypanozoon includes three species Trypanosoma brucei, Trypanosoma evansi and Trypanosoma equiperdum, which are morphologically identical and indistinguishable even using some molecular methods. In this study, PCR-based single strand conformation polymorphism (PCR-SSCP) was used to analyze the ribosomal DNA of the Trypanozoon species. Data indicate different patterns of ITS2 fragments between T. brucei, T. evansi and T. equiperdum by SSCP. Furthermore, analysis of total ITS sequences within these three members of the subgenus Trypanozoon showed a high degree of homology using phylogenetic analysis but were polyphyletic in haplotype networks. These data provide novel nuclear evidence to further support the notion that T. evansi and T. equiperdum should be subspecies or even strains of T. brucei.
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Affiliation(s)
- Yan-Zi Wen
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Zhao-Rong Lun
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China; State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China; Ecosystems & Environment Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK; Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
| | - Geoff Hide
- Ecosystems & Environment Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK; Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK
| | - De-Hua Lai
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, PR China.
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Trypanosoma evansi: detection of Trypanosoma evansi DNA in naturally and experimentally infected animals using TBR(1) & TBR(2) primers. Exp Parasitol 2013; 134:109-14. [PMID: 23454630 DOI: 10.1016/j.exppara.2013.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 07/23/2012] [Accepted: 02/05/2013] [Indexed: 11/24/2022]
Abstract
A polymerase chain reaction (PCR-based) assay was evaluated for detection of Trypanosoma evansi DNA in experimentally infected mice and naturally infected camels, sheep and goats using the set of primers TBr(1) & TBr(2) that amplified 164 bp DNA fragment. The results revealed that PCR-based assay was able to detect T. evansi directly from the blood during both acute and chronic phase of infection in all tested animals and in the blood and tissues of intraperitoneally infected mice depending upon the level of infection in the test samples. PCR was more powerful than CATT/T. evansi and mouse inoculation tests, when detected the infection in mice (24 h) post infection. Present results show that sheep & goats probably play a role in transmission of T. evansi to camels and supported that PCR could be used as a diagnostic tool for epidemiological studies on T. evansi in Egypt.
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Xia Y, Jiang S, Weng S, Lv X, Cheng H, Fang C. Antigen-specific immature dendritic cell vaccine ameliorates anti-dsDNA antibody-induced renal damage in a mouse model. Rheumatology (Oxford) 2011; 50:2187-96. [PMID: 21933790 DOI: 10.1093/rheumatology/ker231] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Dendritic cells (DCs) can inhibit immune response by clonal anergy when immature. Recent studies have shown that immature DCs (iDCs) may serve as a live cell vaccine after specific antigen pulse based on its potential of blocking antibody production. In this study, we aimed to investigate the effects of nuclear antigen-pulsed iDCs in the treatment of lupus-like renal damages induced by anti-dsDNA antibodies. METHODS iDCs were generated from haemopoietic stem cells in bone marrow and then pulsed in vitro with nuclear antigen. The iDC vaccine and corresponding controls were injected into mice with lupus-like renal damages. The evaluation of disease was monitored by biochemical parameters and histological scores. Anti-dsDNA antibody isotypes and T-lymphocyte-produced cytokines were analysed for elucidating therapeutic mechanisms. RESULTS; The mice treated with antigen-pulsed iDCs had a sustained remission of renal damage compared with those injected with non-pulsed iDCs or other controls, including decreased anti-dsDNA antibody level, less proteinuria, lower blood urea nitrogen and serum creatinine values, and improved histological evaluation. Analysis on isotypes of anti-dsDNA antibody showed that iDC vaccine preferentially inhibited the production of IgG3, IgG2b and IgG2a. Furthermore, administration of antigen-treated iDCs to mice resulted in significantly reduced IL-2, IL-4 and IL-12 and IFN-γ produced by T-memory cells. Conversely, the vaccination of antigen-pulsed mature DCs led to increased anti-dsDNA antibody production and an aggravation of lupus-like disease in the model. CONCLUSIONS; These results suggested the high potency of iDC vaccine in preventing lupus-like renal injuries induced by pathogenic autoantibodies.
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Affiliation(s)
- Yumin Xia
- Department of Dermatology, Renmin Hospital of Wuhan University, Wuhan, China.
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In vivo investigations of selected diamidine compounds against Trypanosoma evansi using a mouse model. Antimicrob Agents Chemother 2009; 53:5074-9. [PMID: 19786604 DOI: 10.1128/aac.00422-09] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Surra is an animal pathogenic protozoan infection, caused by Trypanosoma evansi, that develops into a fatal wasting disease. Control measures rely on diagnosis and treatment. However, with the continuous emergence of drug resistance, this tactic is failing, and the pressing need for new chemotherapeutic agents is becoming critical. With the introduction of novel aromatic diamidines, a new category of antitrypanosomal drugs was discovered. Nevertheless, their efficacy within a T. evansi-infected mouse model was not known. In total, 30 compounds previously selected based on their in vitro activity were tested in a T. evansi mouse model of infection. Six of the compounds were capable of curing T. evansi-infected mice at drug doses as low as 0.5 and 0.25 mg/kg of body weight administered for 4 consecutive days, and they were more effective than the standard drugs suramin, diminazene, and quinapyramine. After all selection criteria were applied, three diamidine compounds (DB 75, DB 867, and DB 1192) qualified as lead compounds and were considered to have the potential to act as preclinical candidates against T. evansi infection.
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Young R, Taylor JE, Kurioka A, Becker M, Louis EJ, Rudenko G. Isolation and analysis of the genetic diversity of repertoires of VSG expression site containing telomeres from Trypanosoma brucei gambiense, T. b. brucei and T. equiperdum. BMC Genomics 2008; 9:385. [PMID: 18700033 PMCID: PMC2533676 DOI: 10.1186/1471-2164-9-385] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 08/12/2008] [Indexed: 12/28/2022] Open
Abstract
Background African trypanosomes (including Trypanosoma brucei) are unicellular parasites which multiply in the mammalian bloodstream. T. brucei has about twenty telomeric bloodstream form Variant Surface Glycoprotein (VSG) expression sites (BESs), of which one is expressed at a time in a mutually exclusive fashion. BESs are polycistronic transcription units, containing a variety of families of expression site associated genes (ESAGs) in addition to the telomeric VSG. These polymorphic ESAG families are thought to play a role in parasite-host adaptation, and it has been proposed that ESAG diversity might be related to host range. Analysis of the genetic diversity of these telomeric gene families has been confounded by the underrepresentation of telomeric sequences in standard libraries. We have previously developed a method to selectively isolate sets of trypanosome BES containing telomeres using Transformation associated recombination (TAR) cloning in yeast. Results Here we describe the isolation of repertoires of BES containing telomeres from three trypanosome subspecies: Trypanosoma brucei gambiense DAL 972 (causative agent of West-African trypanosomiasis), T. b. brucei EATRO 2340 (a nonhuman infective strain) and T. equiperdum STIB 818 (which causes a sexually transmitted disease in equines). We have sequenced and analysed the genetic diversity at four BES loci (BES promoter region, ESAG6, ESAG5 and ESAG2) from these three trypanosome BES repertoires. Conclusion With the exception of ESAG2, the BES sequence repertoires derived from T. b. gambiense are both less diverse than and nearly reciprocally monophyletic relative to those from T. b. brucei and T. equiperdum. Furthermore, although we find evidence for adaptive evolution in all three ESAG repertoires in T. b. brucei and T. equiperdum, only ESAG2 appears to be under diversifying selection in T. b. gambiense. This low level of variation in the T. b. gambiense BES sequence repertoires is consistent both with the relatively narrow host range of this subspecies and its apparent long-term clonality. However, our data does not show a clear correlation between size of trypanosome host range and either number of BESs or extent of ESAG genetic diversity.
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Affiliation(s)
- Rosanna Young
- Peter Medawar Building for Pathogen Research, University of Oxford, South Parks Road, Oxford, OX1 3SY, UK.
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Khuchareontaworn S, Singhaphan P, Viseshakul N, Chansiri K. Genetic diversity of Trypanosoma evansi in buffalo based on internal transcribed spacer (ITS) regions. J Vet Med Sci 2008; 69:487-93. [PMID: 17551221 DOI: 10.1292/jvms.69.487] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The nucleotide sequences of 18S rDNA and internal transcribed spacer (ITS) regions were used for studying the relationships of Trypanosoma evansi isolate from a buffalo. The sequences were analyzed and compared to 18S rDNA and the ITS regions of the other Trypanosoma spp. Maximum likelihood phylogenetic trees were constructed using Leishmania major as the outgroup. The tree of 18S rDNA indicated that T. evansi (buffalo B18) isolate was closely related to those of Taiwan and T. brucei stock. The ITS tree showed the genetic diversity among 32 clones of T. evansi (B18) within a single host. This data will be useful for epidemiological and dynamic studies for designing the rational control programs of the disease.
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Affiliation(s)
- Sintawee Khuchareontaworn
- Department of Biochemistry, Faculty of Medicine, Srinakharinwirot University, Sukhumvit, Bangkok, Thailand
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de Oliveira Lima AN, da Silva Santos S, Herrera HM, Gama C, Cupolillo E, Jansen AM, Fernandes O. Trypanosoma evansi: molecular homogeneity as inferred by phenetical analysis of ribosomal internal transcribed spacers DNA of an eclectic parasite. Exp Parasitol 2007; 118:402-7. [PMID: 18158150 DOI: 10.1016/j.exppara.2007.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 09/26/2007] [Accepted: 10/02/2007] [Indexed: 11/27/2022]
Abstract
The protozoan Trypanosoma evansi is described as presenting high morphological and genetic similarities among the isolates despite its biological heterogeneity and wide geographical distribution. PCR amplification of the internal transcribed spacers of the ribosomal gene in combination with the coding region of the 5.8S ribosomal subunit further submitted to restriction enzymes digestion were carried out in DNAs extracted from 41 T. evansi strains isolated from horses, dogs, coatis and capybaras from two distinct regions of the Brazilian Pantanal. We also used one T. evansi isolate from Africa, one from Asia and one isolate of T. b. brucei from Africa. Analysis of the RFLP profiles yielded a unique "riboprinting" that does not vary intraspecifically. These results provide insights on the ribosomal gene organization of T. evansi and showed that ITS analysis by RFLP show high genetic similarity of this locus among isolates of this protozoan parasite.
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Affiliation(s)
- Aneska Norek de Oliveira Lima
- Laboratory of Tripanosomatid Biology, Oswaldo Cruz Institute, FIOCRUZ, Av. Brasil 4365, CEP. 21040-360, Rio de Janeiro/RJ, Brazil
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Li FJ, Gasser RB, Zheng JY, Claes F, Zhu XQ, Lun ZR. Application of multiple DNA fingerprinting techniques to study the genetic relationships among three members of the subgenus Trypanozoon (Protozoa: Trypanosomatidae). Mol Cell Probes 2005; 19:400-7. [PMID: 16146682 DOI: 10.1016/j.mcp.2005.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 07/08/2005] [Indexed: 10/25/2022]
Abstract
Three different DNA fingerprinting techniques, the mobile genetic element (MGE)-PCR, simple sequence repeat (SSR)-PCR and random amplified polymorphic DNA (RAPD)-PCR, were used to define a large set of genetic markers to study genetic similarity within and among Trypanosoma brucei, Trypanosoma equiperdum and Trypanosoma evansi strains (n=18) from China, Africa and South America and to investigate their genetic relationships. Using the three fingerprinting techniques, >890 bands (ranging in size from 0.2 to 2kb) were defined for all 18 strains of Trypanosoma. Within each of the strains, 39-59 bands were defined. The similarity coefficients between strains ranged from approximately 41 to 94%, with a mean of 65%. There was more genetic similarity among strains within T. evansi (mean of approximately 79%) compared with T. equiperdum ( approximately 65%) and T. brucei ( approximately 59%). The similarity coefficient data were used to construct the dendrogram, which revealed that (irrespective of species) the majority of strains from China and South America grouped together to the exclusion of those from Africa. The exceptions were a T. brucei strain from Africa and a T. equiperdum strain of unknown origin. Hence, employing data sets generated using the three different fingerprinting methods, it was not possible to unequivocally distinguish among T. brucei, T. evansi and T. equiperdum, although there was a tendency for T. evansi strains to group together to the exclusion of T. brucei. The findings provide support for the hypothesis that T. evansi originated from a mutated form of T. equiperdum and stimulate further investigations of the genetic make-up and evolution of members of the subgenus Trypanozoon.
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Affiliation(s)
- Feng-Jun Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Center for Parasitic Organisms, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, People's Republic of China
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Claes F, Büscher P, Touratier L, Goddeeris BM. Trypanosoma equiperdum: master of disguise or historical mistake? Trends Parasitol 2005; 21:316-21. [PMID: 15923142 DOI: 10.1016/j.pt.2005.05.010] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 03/10/2005] [Accepted: 05/10/2005] [Indexed: 11/24/2022]
Abstract
After 100 years of research, only a small number of laboratory strains of Trypanosoma equiperdum exists, and the history of most of the strains is unknown. No definitive diagnosis of dourine can be made at the serological or molecular level. Only clinical signs are pathognomonic and international screening relies on an outdated cross-reactive serological test (the complement-fixation test) from 1915, resulting in serious consequences at the practical level. Despite many characterization attempts, no clear picture has emerged of the position of T. equiperdum within the Trypanozoon group. In this article, we highlight the controversies that exist regarding T. equiperdum, and the overlap that occurs with Trypanosoma evansi and Trypanosoma brucei brucei. By revisiting the published data, from the early decades of discovery to the recent serological- and molecular-characterization studies, a new hypothesis arises in which T. equiperdum no longer exists as a separate species and in which current strains can be divided into T. evansi (the historical mistake) and Trypanosoma brucei equiperdum (the master of disguise). Hence, dourine is a disease caused by specific host immune responses to a T. b. equiperdum or T. evansi infection.
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Affiliation(s)
- Filip Claes
- Katholieke Universiteit Leuven Leuven, Faculty of Applied Bioscience and Engineering, Department of Animal Sciences, Kasteelpark Arenberg 30, 3001 Leuven, Belgium.
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Lun ZR, Desser SS. Is the broad range of hosts and geographical distribution of Trypanosoma evansi attributable to the loss of maxicircle kinetoplast DNA? ACTA ACUST UNITED AC 2005; 11:131-3. [PMID: 15275353 DOI: 10.1016/0169-4758(95)80129-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Z R Lun
- Department of Zoology, University of Toronto, Ontario, Canada.
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Claes F, Radwanska M, Urakawa T, Majiwa PAO, Goddeeris B, Büscher P. Variable Surface Glycoprotein RoTat 1.2 PCR as a specific diagnostic tool for the detection of Trypanosoma evansi infections. KINETOPLASTID BIOLOGY AND DISEASE 2004; 3:3. [PMID: 15377385 PMCID: PMC521498 DOI: 10.1186/1475-9292-3-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Accepted: 09/17/2004] [Indexed: 11/12/2022]
Abstract
Background Based on the recently sequenced gene coding for the Trypanosoma evansi (T. evansi) RoTat 1.2 Variable Surface Glycoprotein (VSG), a primer pair was designed targeting the DNA region lacking homology to other known VSG genes. A total of 39 different trypanosome stocks were tested using the RoTat 1.2 based Polymerase Chain Reaction (PCR). Results This PCR yielded a 205 bp product in all T. evansi and in seven out of nine T. equiperdum strains tested. This product was not detected in the DNA from T. b. brucei, T. b. gambiense, T. b. rhodesiense, T. congolense, T. vivax and T. theileri parasites. The Rotat 1.2 PCR detects as few as 10 trypanosomes per reaction with purified DNA from blood samples, i.e. 50 trypanosomes/ml. Conclusion PCR amplification of the RoTat 1.2 VSG gene is a specific marker for T. evansi strains, except T. evansi type B, and is especially useful in dyskinetoplastic strains where kDNA based markers may fail to amplify. Furthermore, our data support previous suggestions that some T. evansi stocks have been previously misclassified as T. equiperdum.
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Affiliation(s)
- Filip Claes
- Faculty of Agriculture and Applied Biological Sciences, K. U. Leuven, Department of Animal Science, Kasteelpark Arenberg 30, 3000 Leuven, Belgium
- Prince Leopold Institute of Tropical Medicine, Department of Parasitology, Nationalestraat 155, Antwerpen, Belgium
| | - Magda Radwanska
- Faculty of Agriculture and Applied Biological Sciences, K. U. Leuven, Department of Animal Science, Kasteelpark Arenberg 30, 3000 Leuven, Belgium
| | - Toyo Urakawa
- International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - Phelix AO Majiwa
- International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - Bruno Goddeeris
- Faculty of Agriculture and Applied Biological Sciences, K. U. Leuven, Department of Animal Science, Kasteelpark Arenberg 30, 3000 Leuven, Belgium
| | - Philip Büscher
- Prince Leopold Institute of Tropical Medicine, Department of Parasitology, Nationalestraat 155, Antwerpen, Belgium
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Moritz E, Seidensticker S, Gottwald A, Maier W, Hoerauf A, Njuguna JT, Kaiser A. The efficacy of inhibitors involved in spermidine metabolism in Plasmodium falciparum, Anopheles stephensi and Trypanosoma evansi. Parasitol Res 2004; 94:37-48. [PMID: 15278440 DOI: 10.1007/s00436-004-1162-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Accepted: 06/17/2004] [Indexed: 11/25/2022]
Abstract
In the present study, we have tested the effect of different polyamine inhibitors of the spermidine metabolizing enzymes deoxyhypusine synthase and homospermidine synthase in different chloroquine resistant Plasmodium falciparum strains, in the mosquito Anopheles stephensi (Diptera: Culicidae) and in a Trypanosoma evansi clone I from strain STIB 806 K China. Recent experiments have shown that agmatine is a growth inhibitor of the malaria parasite P. falciparum (Kaiser et al. 2001) in vitro. A comparison of agmatine efficacy with the new antimalarials artemisinin, triclosan and conventional chloroquine showed similar or even better results on the basis of growth inhibition and the reduction of developmental forms. However, no effect of triclosan or agmatine was observed at the ribonucleic acid level. In a second set of experiments, we tested the effect of 1,7-diaminoheptane and agmatine on oocyst formation in A. stephensi after infection with Plasmodium yoelii. Agmatine had an antisporozoite effect since 1,000 microM led to a 59.5% inhibition of oocysts. A much weaker inhibitor of oocyst formation was 1,7-diaminoheptane. The most effective in in vitro inhibition of T. evansi was dicyclohexylamine, an inhibitor of spermidine biosynthesis with an IC(50 ) value of 47.44 microM and the deoxyhypusine inhibitor 1,7-diaminoheptane with an IC(50) value of 47.80 microM. However, both drugs were ineffective in in vivo experiments in a Trypanosoma mouse model. Two different spermidine analogues, 1,8-diaminooctane and 1,3-diaminopropane with IC(50) values of 171 microM and 181.37 microM, respectively, were moderate inhibitors in vitro and ineffective in vivo.
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Affiliation(s)
- E Moritz
- Institut für Medizinische Parasitologie, Sigmund Freud Strasse 25, 53105 Bonn, Germany
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Claes F, Verloo D, De Waal DT, Majiwa PAO, Baltz T, Goddeeris BM, Büscher P. The expression of RoTat 1.2 variable surface glycoprotein (VSG) in Trypanosoma evansi and T. equiperdum. Vet Parasitol 2004; 116:209-16. [PMID: 14559163 DOI: 10.1016/s0304-4017(02)00359-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to define whether the variable antigenic type RoTat 1.2 is restricted to Trypansoma evansi and could be used as antigen in serological tests to differentiate T. evansi from Trypansoma equiperdum, the appearance of RoTat 1.2-specific antibodies in rabbits, experimentally infected with T. evansi and T. equiperdum, respectively, was analyzed. Ten strains of T. evansi and 11 strains of T. equiperdum originating from Asia, Europe, Africa and Latin America were tested. Rabbit pre-infection sera and sera of days 7, 14, 25, 35 post-infection (p.i.) were analyzed for the presence of antibodies reactive with RoTat 1.2 in immune trypanolysis, ELISA/T. evansi and CATT/T. evansi. Within the duration of the infection (maximum 35 days), all T. evansi as well as 9 out of 11 T. equiperdum infected rabbits became positive in all these tests. The rabbits infected with T. equiperdum OVI (South Africa) and BoTat 1.1 (Morocco) remained negative in the immune trypanolysis test although the latter rabbit became positive in the CATT/T. evansi and ELISA/T. evansi. On the contrary, both rabbits were positive in immune trypanolysis when tested against their respective infecting population. From these data, we conclude that most T. equiperdum strains express isoVATs of RoTat 1.2. This explains, in part, why antibody tests based on T. evansi RoTat 1.2 cannot reliably distinguish between infections caused by T. evansi and those caused by T. equiperdum unless it can be proven that most described T. equiperdum are actually misclassified T. evansi.
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Affiliation(s)
- F Claes
- Department of Parasitology, Prince Leopold Institute of Tropical Medicine, Nationalestraat 155, B-2000, Antwerpen, Belgium
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16
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Lun ZR, Li AX, Chen XG, Lu LX, Zhu XQ. Molecular profiles of Trypanosoma brucei, T. evansi and T. equiperdum stocks revealed by the random amplified polymorphic DNA method. Parasitol Res 2004; 92:335-40. [PMID: 14727188 DOI: 10.1007/s00436-003-1054-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Accepted: 11/19/2003] [Indexed: 10/26/2022]
Abstract
A total of 20 random primers (10-mers) were used to amplify RAPD markers from the genomic DNA of four Trypanosoma brucei stocks from East and West Africa, four T. evansi stocks from Africa, Asia and South America and one T. equiperdum stock from Asia. Between 65 and 88 reproducible fragments ranging from 0.25 to 2.15 kb were generated from these stocks depending on the stock/primer combination. The similarity coefficient (SC) among the stocks of T. brucei from Kenya, Nigeria, Tanzania and Zambia ranged from 62.9% to 74.0% (average: 67.6%). The SC among the stocks of T. evansi from Kenya, China and Brazil was 76.4%-95.5% (average: 86.4%), while the SC between T. evansi stock from China and Brazil was 95.5%. For T. evansi and T. equiperdum, the SC among the stocks ranged from 81.2% to 94.4% (average: 87.6%). As for the SC among the stocks of T. brucei and T. evansi, it was found to be from 54.7% to 80.3% (average: 68.0%) and the SC among stocks of T. brucei and T. equiperdum was from 59.4% to 76.9% (average: 68.1%). Our results indicate that the stocks of T. evansi from China and from Brazil are more closely related to the stock of T. equiperdum from China than to the stocks of T. evansi isolated from Kenya and to the stocks of T. brucei. In addition, our results further support the hypothesis that T. evansi stocks from China and Brazil could have arisen from a single lineage. The possible evolution of T. evansi and T. equiperdum is also discussed.
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Affiliation(s)
- Zhao-Rong Lun
- Center for Parasitic Organisms, School of Life Sciences, Zhongshan University, Guangzhou 510275, PR China,
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17
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Queiroz AO, Legey AP, Xavier SC, Jansen AM. Specific antibody levels and antigenic recognition of Wistar rats inoculated with distinct isolates of Trypanosoma evansi. Mem Inst Oswaldo Cruz 2001; 96:965-72. [PMID: 11685263 DOI: 10.1590/s0074-02762001000700014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
"Mal de Cadeiras", an enzootic disease caused by Trypanosoma evansi, is one of the most important trypanosomiases in the Brazilian Pantanal region. The disease affects mainly horses, which are widely used in extensive cattle production, an activity of greatest economical significance for the region. The parasite also infects sylvan (coatis and capybaras) and domestic (dogs) animals, respectively considered wild and domestic reservoirs of T. evansi. For a better understanding of the interaction of T. evansi with its rodent host, we evaluated the differences in the specific antibody level patterns and in the parasitic peptides recognition patterns of experimentally infected Wistar rats. The rats experimentally infected with T. evansi isolates obtained from coatis, dogs and horses were submitted to indirect immunofluorescence test (IgM e IgG) and Western blotting. The serological titers for IgM and IgG ranged between 1:40 and 1:160. The most recognized polypeptide profiles were in a range of 17 and 74 kDa. Our data suggest that the humoral immune response in Wistar rats is not sufficient for granting an effective control of T. evansi infections.
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Affiliation(s)
- A O Queiroz
- Departamento de Protozoologia, Instituto Oswaldo Cruz-Fiocruz, 21045-900 Rio de Janeiro, RJ, Brasil
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18
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Verloo D, Magnus E, Büscher P. General expression of RoTat 1.2 variable antigen type in Trypanosoma evansi isolates from different origin. Vet Parasitol 2001; 97:183-9. [PMID: 11390070 DOI: 10.1016/s0304-4017(01)00412-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The variable surface glycoprotein of Trypanosoma evansi RoTat 1.2 variable antigen type (VAT) is used as an antigen in different antibody detection assays for T. evansi. To obtain more information on the predominant character of RoTat 1.2 and its diagnostic potential in antibody detection tests, we checked its expression in 10 different T. evansi stocks and clones from different parts of the world. Cryostabilates were injected into mice and the trypanosomes of the first peak parasitaemia were screened for the presence of RoTat 1.2 by VAT specific immunofluorescence. To monitor the appearance of RoTat 1.2 specific antibodies during infection, rabbits were infected and serologically tested at different time intervals with VAT specific immune trypanolysis, CATT/T. evansi, LATEX/T. evansi and ELISA/T. evansi. Test results confirm the predominant character of RoTat 1.2.
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Affiliation(s)
- D Verloo
- Department of Parasitology, Institute of Tropical Medicine, Nationalestraat 155, B-2000, Antwerpen, Belgium
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19
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Dávila AM, Silva RA. Animal trypanosomiasis in South America. Current status, partnership, and information technology. Ann N Y Acad Sci 2001; 916:199-212. [PMID: 11193622 DOI: 10.1111/j.1749-6632.2000.tb05291.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Animal trypanosome species of economical importance in South America include T. vivax and T. evansi. Both species are described in Brazil, Bolivia, Colombia, French Guyana, Peru, Suriname, and Venezuela. In Argentina and Guyana, only T. evansi and T. vivax are found, respectively. Our studies on T. vivax indicated that the parasite was spreading around 1.3 km per day in Bolivia. We found severe leukopenia in bovines from Pantanal (Brazil) and the Department of Santa Cruz (Bolivia). Because it can cause immunosuppression, the importance of trypanosomiasis control in ensuring success of vaccination campaigns against foot and mouth disease (FMD) in the Pantanal and Bolivia should be considered. The use of one needle for several animals during FMD campaigns in Brazil and Bolivia could also contribute to the spread of T. vivax. The anticipated losses due to T. vivax could exceed $160 million, assuming there are 11 million head of cattle in the Brazilian Pantanal and Bolivian lowlands. International collaboration among research institutes is needed to deal with these diseases and parasites. Previous efforts using information technologies resulted in the creation of two discussion lists (Tryplink and Trypan), the edition of the on-line version of Trypnews and Internet conferences.
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Affiliation(s)
- A M Dávila
- Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, 21045-900, Brazil.
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20
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Queiroz AO, Cabello PH, Jansen AM. Biological and biochemical characterization of isolates of Trypanosoma evansi from Pantanal of Matogrosso--Brazil. Vet Parasitol 2000; 92:107-18. [PMID: 10946134 DOI: 10.1016/s0304-4017(00)00286-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Ten isolates of Trypanosoma evansi from the Pantanal region of Brazil, recently derived from coati (Nasua nasua, carnivora, Procyonidae), horses and dogs, were characterized on the basis of biological (experimental infections in Wistar rats) and biochemical (multilocus enzyme eletrophoresis) data. Biological data were analyzed by Nested analysis of variance and Kruskal-Wallis. Marked heterogeneity in virulence was observed in the isolates. Some of the isolates showed an undulating parasitaemia, typical for African trypanosomes. This biological heterogeneity did not correspond with the biochemical homogeneity observed in the T. evansi isolates. T. evansi has one of the widest distributions and greatest range of mammalian hosts and is widely recognized to have evolved from Trypanosoma brucei. Adaptability of T. evansi was not reflected in the variability of biochemical and molecular parameters studied to date. The variability in virulence was very significant, but not correlated with the host from which it was derived. These data suggested that, in the region studied, T. evansi is transmitted among both domestic and sylvatic animals in one single transmission cycle.
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Affiliation(s)
- A O Queiroz
- Department of Protozoology, Instituto Oswaldo Cruz, Fiocruz, A.v. Brasil, 4365, CEP: 21045-900, Rio de Janeiro, Brazil
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21
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Characterization of Trypanozoon isolates using a repeated coding sequence and microsatellite markers. Mol Biochem Parasitol 2000. [DOI: 10.1016/s0166-6851(99)00171-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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Abstract
In the absence of a fossil record, the evolution of protozoa has until recently largely remained a matter for speculation. However, advances in molecular methods and phylogenetic analysis are now allowing interpretation of the "history written in the genes". This review focuses on recent progress in reconstruction of trypanosome phylogeny based on molecular data from ribosomal RNA, the miniexon and protein-coding genes. Sufficient data have now been gathered to demonstrate unequivocally that trypanosomes are monophyletic; the phylogenetic trees derived can serve as a framework to reinterpret the biology, taxonomy and present day distribution of trypanosome species, providing insights into the coevolution of trypanosomes with their vertebrate hosts and vectors. Different methods of dating the divergence of trypanosome lineages give rise to radically different evolutionary scenarios and these are reviewed. In particular, the use of one such biogeographically based approach provides new insights into the coevolution of the pathogens, Trypanosoma brucei and Trypanosoma cruzi, with their human hosts and the history of the diseases with which they are associated.
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Affiliation(s)
- J R Stevens
- School of Biological Sciences, University of Exeter, Exeter EX4 4PS, UK.
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23
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Brun R, Hecker H, Lun ZR. Trypanosoma evansi and T. equiperdum: distribution, biology, treatment and phylogenetic relationship (a review). Vet Parasitol 1998; 79:95-107. [PMID: 9806490 DOI: 10.1016/s0304-4017(98)00146-0] [Citation(s) in RCA: 174] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Trypanosoma evansi and T. equiperdum were compared regarding their ultrastructure, their mammalian hosts, way of transmission, pathogenicity, diagnosis and treatment, and biochemical and molecular characteristics. Electron microscopic investigation revealed no ultrastructural differences between the two species except that there were more coated vesicles in the flagellar pocket of T. equiperdum. Biological, biochemical and molecular studies were reviewed and exhibited many similarities between T. evansi and T. equiperdum. The most prominent differences between the two species are the presence of maxicircles in T. equiperdum, which are missing in T. evansi, and the route of transmission. While T. evansi is transmitted by biting flies, T. equiperdum is transmitted from one equine host to another during copulation when mucous membranes come into contact. Otherwise the two species are remarkably similar. The phylogenetic relationship between the two species and T. b. brucei is being discussed, and the hypothesis is proposed that T. evansi arose from a clone of T. equiperdum which lost its maxicircles.
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Affiliation(s)
- R Brun
- Swiss Tropical Institute, Basel.
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24
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Abstract
Based on phylogenetic analysis of 18S rRNA sequences and clade taxon composition, this paper adopts a biogeographical approach to understanding the evolutionary relationships of the human and primate infective trypanosomes, Trypanosoma cruzi, T. brucei, T. rangeli and T. cyclops. Results indicate that these parasites have divergent origins and fundamentally different patterns of evolution. T. cruzi is placed in a clade with T. rangeli and trypanosomes specific to bats and a kangaroo. The predominantly South American and Australian origins of parasites within this clade suggest an ancient southern super-continent origin for ancestral T. cruzi, possibly in marsupials. T. brucei clusters exclusively with mammalian, salivarian trypanosomes of African origin, suggesting an evolutionary history confined to Africa, while T. cyclops, from an Asian primate appears to have evolved separately and is placed in a clade with T. (Megatrypanum) species. Relating clade taxon composition to palaeogeographic evidence, the divergence of T. brucei and T. cruzi can be dated to the mid-Cretaceous, around 100 million years before present, following the separation of Africa, South America and Euramerica. Such an estimate of divergence time is considerably more recent than those of most previous studies based on molecular clock methods. Perhaps significantly, Salivarian trypanosomes appear, from these data, to be evolving several times faster than Schizotrypanum species, a factor which may have contributed to previous anomalous estimates of divergence times.
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Affiliation(s)
- J Stevens
- School of Biological Sciences, University of Bristol, UK.
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25
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Kaminsky R, Schmid C, Grether Y, Holý A, DeClercq E, Naesens L, Brun R. (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine [(S)-HPMPA]: a purine analogue with trypanocidal activity in vitro and in vivo. Trop Med Int Health 1996; 1:255-63. [PMID: 8665394 DOI: 10.1111/j.1365-3156.1996.tb00036.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The unique features of purine salvage systems of pathogenic haemoflagellates render them selectively susceptible to the cytotoxic effects of purine analogues. A series of acyclic nucleoside phosphonates were evaluated for activity against pathogenic haemoflagellates in vitro. One of the phosphonylmethoxyalkylpurines, namely (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine [(S)-HPMPA], was active in vitro against bloodstream forms of Trypanosoma brucei rhodesiense, T. b. gambiense, multidrug-resistant T. b. brucei, T. congolense and T. evansi, but not against intracellular T. cruzi or Leishmania donovani. Cytotoxic effects against mammalian cells were observed at 4900-27 300-fold higher concentrations than those necessary to inhibit T. b. rhodesiense. (S)-HPMPA was able to eliminate T. b. rhodesiense and multidrug-resistant T. b. brucei in an acute rodent model with two administrations of 10 mg/kg each.
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Affiliation(s)
- R Kaminsky
- Swiss Tropical Institute, Basel, Switzerland
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26
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Boid R, Hunter AG, Jones TW, Ross CA, Sutherland D, Luckins AG. Trypanosomosis research at the Centre for Tropical Veterinary Medicine (CTVM) 1970 to 1995. Trop Anim Health Prod 1996; 28:5-22. [PMID: 8815614 DOI: 10.1007/bf02250724] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This review covers aspects of research work carried out on animal trypanosomes at the Centre for Tropical Veterinary Medicine (CTVM) during the last 25 years. The review covers work on antigenic variation, tissue culture, drug resistance, immunology, biochemistry and pathology of Trypanosoma brucei, T. congolense, T. gambiense and T. evansi. It is not intended as an exhaustive review of the subject but focuses on certain aspects of these areas which are presented in relation to work carried out within the broader scientific community.
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Affiliation(s)
- R Boid
- University of Edinburgh, Centre for Tropical Veterinary Medicine, Roslin, Midlothian, Scotland
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27
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Destro-Bisol G, Santini SA. Electrophoresis on cellulose acetate and cellogel: current status and perspectives. J Chromatogr A 1995. [DOI: 10.1016/0021-9673(94)01279-n] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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28
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Zhang ZQ, Baltz T. Identification of Trypanosoma evansi, Trypanosoma equiperdum and Trypanosoma brucei brucei using repetitive DNA probes. Vet Parasitol 1994; 53:197-208. [PMID: 7975115 DOI: 10.1016/0304-4017(94)90183-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The phylogenetic relatedness of 15 stocks of Trypanosoma evansi, three stocks of Trypanosoma equiperdum and one stock of Trypanosoma brucei brucei was determined using Southern blot analysis of restriction enzyme digested DNA, probed with two repetitive DNA sequences from T. b. brucei. A dendrogram derived by cluster analysis of restriction fragment length polymorphism (RFLP) revealed three groups of related stocks. Group 1 included 14 stocks of T. evansi and one stock of T. equiperdum. Group 2 included two stocks of T. equiperdum and one stock of T. evansi. Group 3 included the one stock of T. brucei brucei. Group 2 is more closely related to Group 3 than Group 1, by analysis of the banding patterns. Further analysis of the T. evansi in Group 1 revealed that the patterns of isolates from different provinces in China were identical, but differed from T. evansi isolated from Africa, South America and the Philippines. These results provide insight into the origins of T. evansi and suggest that RFLP may be a useful means of distinguishing closely related trypanosomes.
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Affiliation(s)
- Z Q Zhang
- Laboratoire d'Immunologie et de Parasitologie Moléculaire, URA 1637, CNRS, Université de Bordeaux II, France
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29
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Abstract
The drug sensitivities of eleven Trypanosoma evansi isolates from China were examined using two different in vitro assays, a 3H-hypoxanthine incorporation assay and a long incubation low inoculation test (LILIT). Better discrimination of the drug susceptibility of the strains was observed with the LILIT. The drug responses of all the isolates to the arsenical melarsoprol were very similar. In contrast, for suramin, minimal inhibitory concentrations (MIC) varied within a 27-fold range and for diminazene within a 55-fold range. Comparison of MIC values with expected drug levels in the host as well as in vivo experiments with selected isolates and drugs indicated that all the isolates examined would be sensitive to melarsoprol, diminazene and suramin under in vivo conditions. For isometamidium, the difference in MIC values between the most and the least sensitive isolate was 724-fold. Neither of two isolates tested in mice--the most resistant and the second most sensitive--was cured with the highest acceptable dose of 10 mg kg-1 isometamidium chloride. Comparison of our results with blood levels of drug to be expected in cattle support the assumption that the Chinese T. evansi isolates have more or less innate resistance to isometamidium under in vivo conditions. One Trypanosoma equiperdum isolate was tested in the 3H-hypoxanthine incorporation assay. The results indicated that this isolate was highly sensitive to melarsoprol, isometamidium and suramin; with regard to diminazene, T. equiperdum was not as sensitive as the most sensitive T. evansi strains.
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Affiliation(s)
- R Brun
- Swiss Tropical Institute, Basel
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