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Pasquier G, Andreotti Q, Ravel C, Sterkers Y. Molecular diagnosis of visceral leishmaniasis: a French study comparing a reference PCR method targeting kinetoplast DNA and a commercial kit targeting ribosomal DNA. Microbiol Spectr 2023; 11:e0215423. [PMID: 37819127 PMCID: PMC10714885 DOI: 10.1128/spectrum.02154-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 08/23/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE PCR revolutionized the direct diagnosis of infectious diseases, especially protozooses, where the infectious load is usually low. Commercial PCR methods are available and offer many advantages, including convenience and batch tracking as part of a quality system. For most parameters, the performance of commercial methods is at least as good as that of finely optimized methods developed in expert laboratories. This comparison work has not been done for the molecular diagnosis of visceral leishmaniasis. Leishmania sp. has a unique organelle, the kinetoplast, which corresponds to the mitochondrial DNA. It is organized into a large number of minicircles, which has made it a target for the development of diagnostic PCR. The quanty Leishmaniae, Clonit kit targeting ribosomal DNA was compared to a widely used laboratory-developed method based on kinetoplast DNA. This reference method gave significantly better results, probably due to the difference in the number of repeats of the PCR targets.
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Affiliation(s)
- Grégoire Pasquier
- Department of Parasitology-Mycology, National Reference Center for Leishmaniasis, University of Montpellier, CNRS, IRD, University Hospital Center (CHU) of Montpellier, Montpellier, France
| | - Quentin Andreotti
- Department of Parasitology-Mycology, National Reference Center for Leishmaniasis, University of Montpellier, CNRS, IRD, University Hospital Center (CHU) of Montpellier, Montpellier, France
| | - Christophe Ravel
- Department of Parasitology-Mycology, National Reference Center for Leishmaniasis, University of Montpellier, CNRS, IRD, University Hospital Center (CHU) of Montpellier, Montpellier, France
| | - Yvon Sterkers
- Department of Parasitology-Mycology, National Reference Center for Leishmaniasis, University of Montpellier, CNRS, IRD, University Hospital Center (CHU) of Montpellier, Montpellier, France
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Dueñas E, Nakamoto JA, Cabrera-Sosa L, Huaihua P, Cruz M, Arévalo J, Milón P, Adaui V. Novel CRISPR-based detection of Leishmania species. Front Microbiol 2022; 13:958693. [PMID: 36187950 PMCID: PMC9520526 DOI: 10.3389/fmicb.2022.958693] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/06/2022] [Indexed: 12/26/2022] Open
Abstract
Tegumentary leishmaniasis, a disease caused by protozoan parasites of the genus Leishmania, is a major public health problem in many regions of Latin America. Its diagnosis is difficult given other conditions resembling leishmaniasis lesions and co-occurring in the same endemic areas. A combination of parasitological and molecular methods leads to accurate diagnosis, with the latter being traditionally performed in centralized reference and research laboratories as they require specialized infrastructure and operators. Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) systems have recently driven innovative tools for nucleic acid detection that combine high specificity, sensitivity and speed and are readily adaptable for point-of-care testing. Here, we harnessed the CRISPR-Cas12a system for molecular detection of Leishmania spp., emphasizing medically relevant parasite species circulating in Peru and other endemic areas in Latin America, with Leishmania (Viannia) braziliensis being the main etiologic agent of cutaneous and mucosal leishmaniasis. We developed two assays targeting multi-copy targets commonly used in the molecular diagnosis of leishmaniasis: the 18S ribosomal RNA gene (18S rDNA), highly conserved across Leishmania species, and a region of kinetoplast DNA (kDNA) minicircles conserved in the L. (Viannia) subgenus. Our CRISPR-based assays were capable of detecting down to 5 × 10−2 (kDNA) or 5 × 100 (18S rDNA) parasite genome equivalents/reaction with PCR preamplification. The 18S PCR/CRISPR assay achieved pan-Leishmania detection, whereas the kDNA PCR/CRISPR assay was specific for L. (Viannia) detection. No cross-reaction was observed with Trypanosoma cruzi strain Y or human DNA. We evaluated the performance of the assays using 49 clinical samples compared to a kDNA real-time PCR assay as the reference test. The kDNA PCR/CRISPR assay performed equally well as the reference test, with positive and negative percent agreement of 100%. The 18S PCR/CRISPR assay had high positive and negative percent agreement of 82.1% and 100%, respectively. The findings support the potential applicability of the newly developed CRISPR-based molecular tools for first-line diagnosis of Leishmania infections at the genus and L. (Viannia) subgenus levels.
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Affiliation(s)
- Eva Dueñas
- Laboratory of Biomolecules, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru
| | - Jose A. Nakamoto
- Laboratory of Biomolecules, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru
| | - Luis Cabrera-Sosa
- Laboratory of Biomolecules, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Percy Huaihua
- Laboratorio de Patho-antígenos, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - María Cruz
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
- Hospital Nacional Adolfo Guevara Velasco, Cusco, Peru
| | - Jorge Arévalo
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
- Laboratorio de Patho-antígenos, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Pohl Milón
- Laboratory of Biomolecules, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru
| | - Vanessa Adaui
- Laboratory of Biomolecules, Faculty of Health Sciences, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
- *Correspondence: Vanessa Adaui,
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Jariyapan N, Bates MD, Bates PA. Molecular identification of two newly identified human pathogens causing leishmaniasis using PCR-based methods on the 3' untranslated region of the heat shock protein 70 (type I) gene. PLoS Negl Trop Dis 2021; 15:e0009982. [PMID: 34847144 PMCID: PMC8631652 DOI: 10.1371/journal.pntd.0009982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/05/2021] [Indexed: 11/18/2022] Open
Abstract
PCR-based methods to amplify the 3′ untranslated region (3′-UTR) of the heat shock protein 70 (type I) gene (HSP70-I) have previously been used for typing of Leishmania but not with Leishmania (Mundinia) martiniquensis and L. (Mundinia) orientalis, newly identified human pathogens. Here, the 3′-UTRs of HSP70-I of L. martiniquensis, L. orientalis, and 10 other species were sequenced and analyzed. PCR-Restriction Fragment Length Polymorphism (RFLP) analysis targeting the 3′-UTR of HSP70-I was developed. Also, the detection limit of HSP70-I-3′-UTR PCR methods was compared with two other commonly used targets: the 18S small subunit ribosomal RNA (SSU-rRNA) gene and the internal transcribed spacer 1 region of the rRNA (ITS1-rRNA) gene. Results showed that HSP70-I-3′-UTR PCR methods could be used to identify and differentiate between L. martiniquensis (480–2 bp) and L. orientalis (674 bp) and distinguished them from parasites of the subgenus Viannia and of the subgenus Leishmania. PCR-RFLP patterns of the 3′-UTR of HSP70-I fragments digested with BsuRI restriction enzyme successfully differentiated L. martiniquensis, L. orientalis, L. braziliensis, L. guyanensis = L. panamensis, L. mexicana = L. aethiopica = L. tropica, L. amazonensis, L. major, and L. donovani = L. infantum. For the detection limit, the HSP70-I-3′-UTR PCR method could detect the DNA of L. martiniquensis and L. orientalis at the same concentration, 1 pg/μL, at a similar level to the SSU-rRNA PCR. The PCR that amplified ITS1-rRNA was more sensitive (0.01 pg/μL) than that of the HSP70-I-3′-UTR PCR. However, the sizes of both SSU-rRNA and ITS1-rRNA PCR amplicons could not differentiate between L. martiniquensis and L. orientalis. This is the first report of using HSP70-I-3′-UTR PCR based methods to identify the parasites causing leishmaniasis in Thailand. Also, the BsuRI-PCR-RFLP method can be used for differentiating some species within other subgenera. L. martiniquensis and L. orientalis, newly identified human pathogens, cause visceral leishmaniasis and cutaneous leishmaniasis in HIV-negative patients, respectively. However, both parasite species cause disseminated cutaneous leishmaniasis accompanying visceral leishmaniasis in HIV-positive patients. Species typing in leishmaniasis is important in diagnostics, epidemiology, and clinical studies. We show here that the 3′-UTR of HSP70-I region is a suitable target for PCR-based identification and discrimination between L. martiniquensis and L. orientalis. The technique is simple to perform and can be implemented in all settings where PCR is available. In species with similar PCR product size, the BsuRI-PCR-RFLP patterns of the 3′-UTR of HSP70-I fragments can be used for differentiating some species within other subgenera. However, where identification of species is essential or there is a travel history outside Thailand, sequencing of the HSP70-I-3′-UTR product or a similar discriminating target sequence is recommended. The PCR-based methods used in this study can also be applicable to the identification of Leishmania species obtained from vectors and reservoirs.
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Affiliation(s)
- Narissara Jariyapan
- Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- * E-mail:
| | - Michelle D. Bates
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom
| | - Paul A. Bates
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom
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Espada CR, Ferreira BA, Ortiz PA, Uliana SRB, Coelho AC. Full nucleotide sequencing of ribosomal DNA internal transcribed spacer of Leishmania species causing cutaneous leishmaniasis in Brazil and its potential for species typing. Acta Trop 2021; 223:106093. [PMID: 34389323 DOI: 10.1016/j.actatropica.2021.106093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/07/2021] [Accepted: 08/01/2021] [Indexed: 10/20/2022]
Abstract
Species-specific diagnosis still represents a challenge in leishmaniasis management, particularly in regions with multiple endemic species. In Brazil, seven species have been recognized as etiological agents of cutaneous leishmaniasis. The disease comprises complex clinical presentation patterns, classified as localized, diffuse, disseminated and mucocutaneous leishmaniasis. In this study, we characterized the full nucleotide sequence of a region comprising the ribosomal DNA internal transcribed spacers 1 and 2 and 5.8 S gene of reference strains of Leishmania (Viannia) species reported as causative agents of human leishmaniasis in Brazil. The analysis of the nucleotide sequence of this region was able to discriminate species in the Leishmania (Viannia) subgenus and to determine intra- and interspecies phylogenetic relationships.
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Affiliation(s)
- Caroline R Espada
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Bianca A Ferreira
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - Paola A Ortiz
- Departamento de Biologia, Facultad de Ciencias Básicas, Universidad del Tolima, Tolima, Colombia
| | - Silvia R B Uliana
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Adriano C Coelho
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil.
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Tanida K, Balczun C, Hahn A, Veit A, Nickel B, Poppert S, Scheid PL, Hagen RM, Frickmann H, Loderstädt U, Tannich E. Comparison of Three In-House Real PCR Assays Targeting Kinetoplast DNA, the Small Subunit Ribosomal RNA Gene and the Glucose-6-Phosphate Isomerase Gene for the Detection of Leishmania spp. in Human Serum. Pathogens 2021; 10:pathogens10070826. [PMID: 34209257 PMCID: PMC8308501 DOI: 10.3390/pathogens10070826] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 12/28/2022] Open
Abstract
To perform PCR from serum for the diagnosis of visceral leishmaniasis is convenient and much less invasive than the examination of deeper compartments such as bone marrow. We compared three Leishmania-specific real-time PCRs with three different molecular targets (kinetoplast DNA, the small subunit-ribosomal RNA-(ssrRNA-)gene, the glucose-6-phosphate isomerase-(gpi-)gene) regarding their sensitivity and specificity in human serum. Residual sera from previous diagnostic assessments at the German National Reference Center for Tropical Pathogens Bernhard Nocht Institute for Tropical Medicine Hamburg and the Swiss Tropical and Public Health Institute were used. The sensitivities of kinetoplast DNA-PCR, ssrRNA-gene PCR, and gpi-PCR were 93.3%, 73.3%, and 33.3%, respectively, with 15 initial serum samples from visceral leishmaniasis patients, as well as 9.1%, 9.1%, and 0.0%, respectively, with 11 follow-up serum samples taken at various time points following anti-leishmanial therapy. Specificity was 100.0% in all assays as recorded with 1.137 serum samples from deployed soldiers and migrants without clinical suspicion of visceral leishmaniasis. Kinetoplast-DNA PCR from serum was confirmed as a sensitive and specific approach for the diagnosis of visceral leishmaniasis. The results also indicate the suitability of serum PCR for diagnostic follow-up after therapy, in particular regarding therapeutic failure in case of persisting positive PCR results.
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Affiliation(s)
- Konstantin Tanida
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, 20359 Hamburg, Germany;
| | - Carsten Balczun
- Department XXI, Microbiology and Hospital Hygiene, Section B, Bundeswehr Central Hospital Koblenz, 56070 Koblenz, Germany; (C.B.); (P.L.S.); (R.M.H.)
| | - Andreas Hahn
- Department of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, 18057 Rostock, Germany;
| | - Alexandra Veit
- Bernhard Nocht Institute for Tropical Medicine Hamburg, National Reference Centre for Tropical Pathogens, 20359 Hamburg, Germany; (A.V.); (E.T.)
| | - Beatrice Nickel
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; (B.N.); (S.P.)
- University of Basel, 4001 Basel, Switzerland
| | - Sven Poppert
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; (B.N.); (S.P.)
- University of Basel, 4001 Basel, Switzerland
| | - Patrick Leander Scheid
- Department XXI, Microbiology and Hospital Hygiene, Section B, Bundeswehr Central Hospital Koblenz, 56070 Koblenz, Germany; (C.B.); (P.L.S.); (R.M.H.)
| | - Ralf Matthias Hagen
- Department XXI, Microbiology and Hospital Hygiene, Section B, Bundeswehr Central Hospital Koblenz, 56070 Koblenz, Germany; (C.B.); (P.L.S.); (R.M.H.)
| | - Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, 20359 Hamburg, Germany;
- Department of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, 18057 Rostock, Germany;
- Correspondence: ; Tel.: +49-40-6947-28743
| | - Ulrike Loderstädt
- Department of Hospital Hygiene & Infectious Diseases, University Medicine Göttingen, 37075 Göttingen, Germany;
| | - Egbert Tannich
- Bernhard Nocht Institute for Tropical Medicine Hamburg, National Reference Centre for Tropical Pathogens, 20359 Hamburg, Germany; (A.V.); (E.T.)
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Thomaz C, de Mello CX, Espíndola ODM, Shubach ADO, Quintella LP, de Oliveira RVC, Duarte ACG, Pimentel MIF, Lyra MR, Marzochi MCDA. Comparison of parasite load by qPCR and histopathological changes of inner and outer edge of ulcerated cutaneous lesions of cutaneous leishmaniasis. PLoS One 2021; 16:e0243978. [PMID: 33476320 PMCID: PMC7819606 DOI: 10.1371/journal.pone.0243978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 12/02/2020] [Indexed: 11/29/2022] Open
Abstract
Background Cutaneous leishmaniasis (CL) is an infectious vector-borne disease caused by protozoa of the Leishmania genus that affects humans and animals. The distribution of parasites in the lesion is not uniform, and there are divergences in the literature about the choice of the better sampling site for diagnosis–inner or outer edge of the ulcerated skin lesion. In this context, determining the region of the lesion with the highest parasite density and, consequently, the appropriate site for collecting samples can define the success of the laboratory diagnosis. Hence, this study aims to comparatively evaluate the parasite load by qPCR, quantification of amastigotes forms in the direct exam, and the histopathological profile on the inner and outer edges of ulcerated CL lesions. Methods Samples from ulcerated skin lesions from 39 patients with confirmed CL were examined. We performed scraping of the ulcer inner edge (base) and outer edge (raised border) and lesion biopsy for imprint and histopathological examination. Slides smears were stained by Giemsa and observed in optical microscopy, the material contained on the smears was used to determine parasite load by quantitative real-time PCR (qPCR) with primers directed to the Leishmania (Viannia) minicircle kinetoplast DNA. The histopathological exam was performed to evaluate cell profile, tissue alterations and semi-quantitative assessment of amastigote forms in inner and outer edges. Principal findings Parasite loads were higher on the inner edge compared to the outer edge of the lesions, either by qPCR technique (P<0.001) and histopathological examination (P< 0.003). There was no significant difference in the parasite load between the imprint and scraping on the outer edge (P = 1.0000). Conclusion/Significance The results suggest that clinical specimens from the inner edge of the ulcerated CL lesions are the most suitable for both molecular diagnosis and direct parasitological examination.
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Affiliation(s)
- Caio Thomaz
- Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
- Laboratório de Pesquisa Clínica e Vigilância em Leishmanioses, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - Cintia Xavier de Mello
- Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
- * E-mail:
| | - Otávio de Melo Espíndola
- Laboratório de Pesquisa Clínica em Neuroinfecções, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - Armando de Oliveira Shubach
- Laboratório de Pesquisa Clínica e Vigilância em Leishmanioses, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - Leonardo Pereira Quintella
- Serviço de Anatomia Patológica, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | | | - Adriane Corrêa Gomes Duarte
- Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - Maria Inês Fernandes Pimentel
- Laboratório de Pesquisa Clínica e Vigilância em Leishmanioses, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - Marcelo Rosandiski Lyra
- Laboratório de Pesquisa Clínica e Vigilância em Leishmanioses, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - Mauro Celio de Almeida Marzochi
- Laboratório de Pesquisa Clínica e Vigilância em Leishmanioses, Instituto Nacional de Infectologia Evandro Chagas (INI), Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
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Performance of a universal PCR assay to identify different Leishmania species causative of Old World cutaneous leishmaniasis. Parasit Vectors 2020; 13:431. [PMID: 32854753 PMCID: PMC7450935 DOI: 10.1186/s13071-020-04261-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/23/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The characterization of Leishmania species is important for clinical management of the diseases and the epidemiological control of the parasite distribution. Most of the published polymerase chain reaction (PCR) amplification methods lack the ability to identify all species complexes, have low performance and usually need post-PCR procedures. There is a need for improving the diagnosis of CL by development of an accurate affordable PCR method to identify all Leishmania species in clinical specimens. METHODS We designed an optimized a PCR amplifying the internal transcribed spacer 2 sequence of the ribosomal RNA gene (ITS2) aligned from different strains of CL-causing Leishmania species in the Old World. The performance of the method was evaluated on lesion samples from several CL suspected patients and the limit of detection (LOD) was determined on DNA of promastigotes from reference strains. RESULTS The universal PCR enabled simultaneous discrimination of L. major, L. tropica and L. infantum using one primer pair in one reaction. Stained smear microscopy and Novy-MacNeal-Nicolle (NNN) medium culture alone detected 77.27% (17/22) and 72.73% (16/22) of the positive CL samples, respectively. The PCR assay showed 100% sensitivity (22/22) (95% CI: 84.56-100%) and 100% specificity (3/3) (95% CI: 29.24-100%) for species identification on isolates from lesion scraping/exudate and 100% sensitivity (13/13) (95% CI: 75.29-100%) and 100% specificity (11/11) (95% CI: 71.51-100%) for species identification on biopsy samples of CL patients, while being capable to successfully amplify as little as 0.01-0.1 pg of Leishmania DNA from cultured promastigotes. CONCLUSIONS We present a validated easy-to-use affordable universal PCR assay to identify the most common Old World Leishmania species causing CL. This PCR assay could be used as a sensitive/specific technique to diagnose CL-causing Leishmania species in clinical samples with high accuracy.
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Cuypers B, Berg M, Imamura H, Dumetz F, De Muylder G, Domagalska MA, Rijal S, Bhattarai NR, Maes I, Sanders M, Cotton JA, Meysman P, Laukens K, Dujardin JC. Integrated genomic and metabolomic profiling of ISC1, an emerging Leishmania donovani population in the Indian subcontinent. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2018; 62:170-178. [PMID: 29679745 PMCID: PMC6261844 DOI: 10.1016/j.meegid.2018.04.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/14/2018] [Accepted: 04/17/2018] [Indexed: 01/06/2023]
Abstract
Leishmania donovani is the responsible agent for visceral leishmaniasis (VL) in the Indian subcontinent (ISC). The disease is lethal without treatment and causes 0.2 to 0.4 million cases each year. Recently, reports of VL in Nepalese hilly districts have increased as well as VL cases caused by L. donovani from the ISC1 genetic group, a new and emerging genotype. In this study, we perform for the first time an integrated, untargeted genomics and metabolomics approach to characterize ISC1, in comparison with the Core Group (CG), main population that drove the most recent outbreak of VL in the ISC. We show that the ISC1 population is very different from the CG, both at genome and metabolome levels. The genomic differences include SNPs, CNV and small indels in genes coding for known virulence factors, immunogens and surface proteins. Both genomic and metabolic approaches highlighted dissimilarities related to membrane lipids, the nucleotide salvage pathway and the urea cycle in ISC1 versus CG. Many of these pathways and molecules are important for the interaction with the host/extracellular environment. Altogether, our data predict major functional differences in ISC1 versus CG parasites, including virulence. Therefore, particular attention is required to monitor the fate of this emerging ISC1 population in the ISC, especially in a post-VL elimination context.
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Affiliation(s)
- Bart Cuypers
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Mathematics and Computer Science, University of Antwerp, Antwerp, Belgium
| | - Maya Berg
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Hideo Imamura
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Franck Dumetz
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Géraldine De Muylder
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | | | - Suman Rijal
- BP Koirala Institute of Health Sciences, Dharan, Nepal
| | | | - Ilse Maes
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Mandy Sanders
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - James A Cotton
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Pieter Meysman
- Department of Mathematics and Computer Science, University of Antwerp, Antwerp, Belgium
| | - Kris Laukens
- Department of Mathematics and Computer Science, University of Antwerp, Antwerp, Belgium
| | - Jean-Claude Dujardin
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
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Rastrojo A, García-Hernández R, Vargas P, Camacho E, Corvo L, Imamura H, Dujardin JC, Castanys S, Aguado B, Gamarro F, Requena JM. Genomic and transcriptomic alterations in Leishmania donovani lines experimentally resistant to antileishmanial drugs. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:246-264. [PMID: 29689531 PMCID: PMC6039315 DOI: 10.1016/j.ijpddr.2018.04.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 03/10/2018] [Accepted: 04/10/2018] [Indexed: 12/20/2022]
Abstract
Leishmaniasis is a serious medical issue in many countries around the World, but it remains largely neglected in terms of research investment for developing new control and treatment measures. No vaccines exist for human use, and the chemotherapeutic agents currently used are scanty. Furthermore, for some drugs, resistance and treatment failure are increasing to alarming levels. The aim of this work was to identify genomic and trancriptomic alterations associated with experimental resistance against the common drugs used against VL: trivalent antimony (SbIII, S line), amphotericin B (AmB, A line), miltefosine (MIL, M line) and paromomycin (PMM, P line). A total of 1006 differentially expressed transcripts were identified in the S line, 379 in the A line, 146 in the M line, and 129 in the P line. Also, changes in ploidy of chromosomes and amplification/deletion of particular regions were observed in the resistant lines regarding the parental one. A series of genes were identified as possible drivers of the resistance phenotype and were validated in both promastigotes and amastigotes from Leishmania donovani, Leishmania infantum and Leishmania major species. Remarkably, a deletion of the gene LinJ.36.2510 (coding for 24-sterol methyltransferase, SMT) was found to be associated with AmB-resistance in the A line. In the P line, a dramatic overexpression of the transcripts LinJ.27.T1940 and LinJ.27.T1950 that results from a massive amplification of the collinear genes was suggested as one of the mechanisms of PMM resistance. This conclusion was reinforced after transfection experiments in which significant PMM-resistance was generated in WT parasites over-expressing either gene LinJ.27.1940 (coding for a D-lactate dehydrogenase-like protein, D-LDH) or gene LinJ.27.1950 (coding for an aminotransferase of branched-chain amino acids, BCAT). This work allowed to identify new drivers, like SMT, the deletion of which being associated with resistance to AmB, and the tandem D-LDH-BCAT, the amplification of which being related to PMM resistance.
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Affiliation(s)
- Alberto Rastrojo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Paola Vargas
- Instituto de Parasitología y Biomedicina ''López-Neyra'' (IPBLN-CSIC), Granada, Spain
| | - Esther Camacho
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura Corvo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Hideo Imamura
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Jean-Claude Dujardin
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Santiago Castanys
- Instituto de Parasitología y Biomedicina ''López-Neyra'' (IPBLN-CSIC), Granada, Spain
| | - Begoña Aguado
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Francisco Gamarro
- Instituto de Parasitología y Biomedicina ''López-Neyra'' (IPBLN-CSIC), Granada, Spain.
| | - Jose M Requena
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.
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Tiwananthagorn S, Kato H, Yeewa R, Muengpan A, Polseela R, Leelayoova S. Comparison of LAMP and PCR for molecular mass screening of sand flies for Leishmania martiniquensis infection. Mem Inst Oswaldo Cruz 2017; 112:100-107. [PMID: 28177044 PMCID: PMC5293119 DOI: 10.1590/0074-02760160254] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 10/25/2016] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Leishmaniasis caused by Leishmania martiniquensis infection has been reported in human and domestic animals of Martinique Island, Germany, Switzerland, USA, Myanmar and Thailand. The peculiar clinical features of disseminated cutaneous and visceral forms co-existence render the urgent need of specific diagnostic tool to identify the natural sand fly vectors for effective prevention and control strategies. Loop-mediated isothermal amplification (LAMP) of 18S rRNA gene as well as polymerase chain reaction (PCR) of minicircle kinetoplast DNA gene (PCR-mkDNA) have never been applied to detect L. martiniquensis and L. siamensis in sand fly vectors. OBJECTIVE The present study was aimed to validate malachite green-LAMP (MG-LAMP) and PCR-mkDNA techniques to detect L. martiniquensis in sand fly vectors, compared with the conventional PCR of internal transcribed spacer 1 (PCR-ITS1). METHODS We compared the validity of LAMP of 18S rRNA gene and PCR-mkDNA, to PCR-ITS1 in simulation model of L. martiniquensis infection in Sergentomyia gemmea sand flies. Attributable to the sensitivity and specificity, PCR-mkDNA was consecutively applied to detect L. martiniquensis in 380 female sand fly individuals captured in the newly identified affected region of Lamphun Province, Thailand. FINDINGS AND MAIN CONCLUSIONS Results showed that PCR-mkDNA could detect at least one promastigote per sand fly, which was 10-time superior to LAMP and PCR-ITS1. In addition, PCR-mkDNA was more specific, able to differentiate L. martiniquensis from other viscerotropic Leishmania species, such as L. siamensis, L. (L.) donovani, and L. (L.) infantum. Consecutively, mass screening of L. martiniquensis in 380 female sand fly individuals by PCR-mkDNA was implemented in a new affected area of Thailand where a patient with leishmaniasis/HIV co-infection resides; however Leishmania DNA was undetected. In conclusion, PCR-mkDNA is a promising tool for molecular mass screening of L. martiniquensis infection in outbreak areas where several species of Leishmania and sand flies co-exist.
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Affiliation(s)
- Saruda Tiwananthagorn
- Chiang Mai University, Faculty of Veterinary Medicine, Department of Veterinary Biosciences and Veterinary Public Health, Muang, Chiang Mai, Thailand
| | - Hirotomo Kato
- Jichi Medical University, Department of Infection and Immunity, Division of Medical Zoology, Tochigi, Japan
| | - Ranchana Yeewa
- Chiang Mai University, Faculty of Veterinary Medicine, Department of Veterinary Biosciences and Veterinary Public Health, Muang, Chiang Mai, Thailand
| | - Amontip Muengpan
- Chiang Mai University, Faculty of Veterinary Medicine, Department of Veterinary Biosciences and Veterinary Public Health, Muang, Chiang Mai, Thailand
| | - Raxsina Polseela
- Naresuan University, Faculty of Medical Science, Department of Microbiology and Parasitology, Phitsanulok, Thailand
| | - Saovanee Leelayoova
- Phramongkutklao College of Medicine, Department of Parasitology, Bangkok, Thailand
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Stiles JK, Hicock PI, Shah PH, Meade JC. Genomic organization, transcription, splicing and gene regulation inLeishmania. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.1999.11813485] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Jacquiod S, Stenbæk J, Santos SS, Winding A, Sørensen SJ, Priemé A. Metagenomes provide valuable comparative information on soil microeukaryotes. Res Microbiol 2016; 167:436-50. [DOI: 10.1016/j.resmic.2016.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/16/2016] [Accepted: 03/20/2016] [Indexed: 02/02/2023]
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Santos SS, Nielsen TK, Hansen LH, Winding A. Comparison of three DNA extraction methods for recovery of soil protist DNA. J Microbiol Methods 2015; 115:13-9. [PMID: 25966645 DOI: 10.1016/j.mimet.2015.05.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 04/30/2015] [Accepted: 05/07/2015] [Indexed: 11/24/2022]
Abstract
The use of molecular methods to investigate protist communities in soil is in rapid development this decade. Molecular analysis of soil protist communities is usually dependant on direct genomic DNA extraction from soil and inefficient or differential DNA extraction of protist DNA can lead to bias in downstream community analysis. Three commonly used soil DNA extraction methods have been tested on soil samples from three European Long-Term Observatories (LTOs) with different land-use and three protist cultures belonging to different phylogenetic groups in different growth stages. The methods tested were: ISOm-11063 (a version of the ISO-11063 method modified to include a FastPrep ®-24 mechanical lysis step), GnS-GII (developed by the GenoSol platform to extract soil DNA in large-scale soil surveys) and a commercial DNA extraction kit - Power Lyzer™ PowerSoil® DNA Isolation Kit (MoBio). DNA yield and quality were evaluated along with DNA suitability for amplification of 18S rDNA fragments by PCR. On soil samples, ISOm-11063 yields significantly higher DNA for two of the three soil samples, however, MoBio extraction favors DNA quality. This method was also more effective to recover copies of 18S rDNA numbers from all soil types. In addition and despite the lower yields, higher DNA quality was observed with DNA extracted from protist cultures with the MoBio method. Likewise, a bead-beating step shows to be a good solution for DNA extraction of soil protists, since the recovery of DNA from protist cultures and from the different soil samples with the ISOm method proved to be efficient in recovering PCR-amplifiable DNA. This study showed that soil DNA extraction methods provide biased results towards the cyst stages of protist organism.
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Affiliation(s)
- Susana S Santos
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Tue Kjærgaard Nielsen
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Lars H Hansen
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Anne Winding
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
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Abstract
Leishmania is an infectious protozoan parasite related to African and American trypanosomes. All Leishmania species that are pathogenic to humans can cause dermal disease. When one is confronted with cutaneous leishmaniasis, identification of the causative species is relevant in both clinical and epidemiological studies, case management, and control. This review gives an overview of the currently existing and most used assays for species discrimination, with a critical appraisal of the limitations of each technique. The consensus taxonomy for the genus is outlined, including debatable species designations. Finally, a numerical literature analysis is presented that describes which methods are most used in various countries and regions in the world, and for which purposes.
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Affiliation(s)
- Gert Van der Auwera
- Institute of Tropical Medicine, Department of Biomedical Sciences, Antwerp, Belgium
| | - Jean-Claude Dujardin
- Institute of Tropical Medicine, Department of Biomedical Sciences, Antwerp, Belgium Antwerp University, Department of Biomedical Sciences, Antwerp, Belgium
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Hitakarun A, Tan-ariya P, Siripattanapipong S, Mungthin M, Piyaraj P, Naaglor T, Siriyasatien P, Tiwananthagorn S, Leelayoova S. Comparison of PCR methods for detection of Leishmania siamensis infection. Parasit Vectors 2014; 7:458. [PMID: 25274259 PMCID: PMC4188918 DOI: 10.1186/s13071-014-0458-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/21/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Leishmania siamensis, a newly identified species, has been reported as a causative agent of leishmaniasis in Thailand. This organism has been identified and genetically characterized using PCR techniques based on several target genes. However, the sensitivities and specificities of these methods for the diagnosis of L. siamensis infection have never been evaluated. METHODS To evaluate the sensitivities and specificities of PCR methods to detect L. siamensis infection, PCR for different genetic markers, i.e., the small subunit ribosomal RNA region (SSU-rRNA), the internal transcribed spacer 1 region (ITS1), cysteine protease B (cpb), cytochrome b (cyt b), heat shock protein 70 (hsp70), the spliced leader mini-exon, and the triose-phosphate isomerase (tim) genes were compared. RESULTS Both the ITS1-PCR and the SSU rRNA-PCR could detect promastigote of L. siamensis at concentrations as low as 0.05 parasites/μl or the DNA concentration at 2.3 pg/μl. Though the ITS1-PCR method only recognized 8 samples as positive, all of these could be assessed as true positive according to microscopic diagnosis and/or amplifying the results of the PCR and their sequencing, while other methods also produced false positive results. Compared with the ITS1-PCR method, the PCR amplified SSU-rRNA and cpb gene showed 100% sensitivity for the detection of L. siamensis in clinical specimens. The PCR amplified mini-exon and hsp70 gene also gave a high sensitivity of 87.5%. In contrast, the PCR methods for cyt b and tim gene showed low sensitivity. The PCR methods for cyt b, mini-exon and tim gene showed 100% specificity compared with the ITS1-PCR. CONCLUSION As a result, the ITS1-PCR method is a suitable target for PCR-based detection of L. siamensis infection in clinical specimens due to its high sensitivity and specificity. The results of this study can be used for molecular diagnosis as well as in epidemiological studies of L. siamensis in affected areas.
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Affiliation(s)
- Atitaya Hitakarun
- Department of Microbiology, Faculty of Science, Mahidol University, Ratchawithi Rd., Ratchathewi, Bangkok, 10400, Thailand.
| | - Peerapan Tan-ariya
- Department of Microbiology, Faculty of Science, Mahidol University, Ratchawithi Rd., Ratchathewi, Bangkok, 10400, Thailand.
| | | | - Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, 10400, Thailand.
| | - Phunlerd Piyaraj
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, 10400, Thailand.
| | - Tawee Naaglor
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, 10400, Thailand.
| | - Padet Siriyasatien
- Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Saruda Tiwananthagorn
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, 50100, Thailand.
| | - Saovanee Leelayoova
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, 10400, Thailand.
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Silva-Almeida M, Souza-Silva F, Pereira BAS, Ribeiro-Guimarães ML, Alves CR. Overview of the organization of protease genes in the genome of Leishmania spp. Parasit Vectors 2014; 7:387. [PMID: 25142315 PMCID: PMC4158035 DOI: 10.1186/1756-3305-7-387] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/14/2014] [Indexed: 12/22/2022] Open
Abstract
Background The genus Leishmania includes protozoan parasites that are able to infect an array of phlebotomine and vertebrate species. Proteases are related to the capacity of these parasites to infect and survive in their hosts and are therefore classified as virulence factors. Findings By analyzing protease genes annotated in the genomes of four Leishmania spp [Leishmania (Leishmania) infantum, L. (L.) major, L. (L.) mexicana and L. (Viannia) braziliensis], these genes were found on every chromosome of these protozoa. Four protease classes were studied: metallo-, serine, cysteine and aspartic proteases. Metalloprotease genes predominate in the L. (V.) braziliensis genome, while in the other three species studied, cysteine protease genes prevail. Notably, cysteine and serine protease genes were found to be very abundant, as they were found on all chromosomes of the four studied species. In contrast, only three aspartic protease genes could be detected in these four species. Regarding gene conservation, a higher number of conserved alleles was observed for cysteine proteases (42 alleles), followed by metalloproteases (35 alleles) and serine proteases (15 alleles). Conclusions The present study highlights substantial differences in the organization of protease genes among L. (L.) infantum, L. (L.) major, L. (L.) mexicana and L. (V.) braziliensis. We observed significant distinctions in many protease features, such as occurrence, quantity and conservation. These data indicate a great diversity of protease genes among Leishmania species, an aspect that may be related to their adaptations to the peculiarities of each microenvironment they inhabit, such as the gut of phlebotomines and the immune cells of vertebrate hosts. Electronic supplementary material The online version of this article (doi:10.1186/1756-3305-7-387) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | - Carlos Roberto Alves
- Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Av, Brasil 4365, Rio de, Janeiro CEP 21040-900, Brasil.
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Graça GCD, Volpini AC, Romero GAS, Oliveira Neto MPD, Hueb M, Porrozzi R, Boité MC, Cupolillo E. Development and validation of PCR-based assays for diagnosis of American cutaneous leishmaniasis and identification of the parasite species. Mem Inst Oswaldo Cruz 2013; 107:664-74. [PMID: 22850958 DOI: 10.1590/s0074-02762012000500014] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 04/02/2012] [Indexed: 11/21/2022] Open
Abstract
In this study, PCR assays targeting different Leishmania heat-shock protein 70 gene (hsp70) regions, producing fragments ranging in size from 230-390 bp were developed and evaluated to determine their potential as a tool for the specific molecular diagnosis of cutaneous leishmaniasis (CL). A total of 70 Leishmania strains were analysed, including seven reference strains (RS) and 63 previously typed strains. Analysis of the RS indicated a specific region of 234 bp in the hsp70 gene as a valid target that was highly sensitive for detection of Leishmania species DNA with capacity of distinguishing all analyzed species, after polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). This PCR assay was compared with other PCR targets used for the molecular diagnosis of leishmaniasis: hsp70 (1400-bp region), internal transcribed spacer (ITS)1 and glucose-6-phosphate dehydrogenase (G6pd). A good agreement among the methods was observed concerning the Leishmania species identification. Moreover, to evaluate the potential for molecular diagnosis, we compared the PCR targets hsp70-234 bp, ITS1, G6pd and mkDNA using a panel of 99 DNA samples from tissue fragments collected from patients with confirmed CL. Both PCR-hsp70-234 bp and PCR-ITS1 detected Leishmania DNA in more than 70% of the samples. However, using hsp70-234 bp PCR-RFLP, identification of all of the Leishmania species associated with CL in Brazil can be achieved employing a simpler and cheaper electrophoresis protocol.
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Affiliation(s)
- Grazielle Cardoso da Graça
- Laboratório de Pesquisa em Leishmaniose, Coleção de Leishmania, Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
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Abstract
Leishmaniasis, like other neglected diseases is characterized by a small arsenal of drugs for its control. To safeguard the efficacy of current drugs and guide the development of new ones it is thus of utmost importance to acquire a deep understanding of the phenomenon of drug resistance and its link with treatment outcome. We discuss here how (post-)genomic approaches may contribute to this purpose. We highlight the need for a clear definition of the phenotypes under consideration: innate and acquired resistance versus treatment failure. We provide a recent update of our knowledge on the Leishmania genome structure and dynamics, and compare the contribution of targeted and untargeted methods for the understanding of drug resistance and show their limits. We also present the main assays allowing the experimental validation of the genes putatively involved in drug resistance. The importance of analysing information downstream of the genome is stressed and further illustrated by recent metabolomics findings. Finally, the attention is called onto the challenges for implementing the acquired knowledge to the benefit of the patients and the population at risk.
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Downing T, Imamura H, Decuypere S, Clark TG, Coombs GH, Cotton JA, Hilley JD, de Doncker S, Maes I, Mottram JC, Quail MA, Rijal S, Sanders M, Schönian G, Stark O, Sundar S, Vanaerschot M, Hertz-Fowler C, Dujardin JC, Berriman M. Whole genome sequencing of multiple Leishmania donovani clinical isolates provides insights into population structure and mechanisms of drug resistance. Genome Res 2011; 21:2143-56. [PMID: 22038251 DOI: 10.1101/gr.123430.111] [Citation(s) in RCA: 311] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Visceral leishmaniasis is a potentially fatal disease endemic to large parts of Asia and Africa, primarily caused by the protozoan parasite Leishmania donovani. Here, we report a high-quality reference genome sequence for a strain of L. donovani from Nepal, and use this sequence to study variation in a set of 16 related clinical lines, isolated from visceral leishmaniasis patients from the same region, which also differ in their response to in vitro drug susceptibility. We show that whole-genome sequence data reveals genetic structure within these lines not shown by multilocus typing, and suggests that drug resistance has emerged multiple times in this closely related set of lines. Sequence comparisons with other Leishmania species and analysis of single-nucleotide diversity within our sample showed evidence of selection acting in a range of surface- and transport-related genes, including genes associated with drug resistance. Against a background of relative genetic homogeneity, we found extensive variation in chromosome copy number between our lines. Other forms of structural variation were significantly associated with drug resistance, notably including gene dosage and the copy number of an experimentally verified circular episome present in all lines and described here for the first time. This study provides a basis for more powerful molecular profiling of visceral leishmaniasis, providing additional power to track the drug resistance and epidemiology of an important human pathogen.
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Affiliation(s)
- Tim Downing
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, United Kingdom
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Abstract
The post-genomics era has provided researchers with access to a new generation of tools for the global characterization and understanding of pathogen diversity. This review provides a critical summary of published Leishmania post-genomic research efforts to date, and discusses the potential impact of the addition of metabolomics to the post-genomic toolbox. Metabolomics aims at understanding biology by comprehensive metabolite profiling. We present an overview of the design and interpretation of metabolomics experiments in the context of Leishmania research. Sample preparation, measurement techniques, and bioinformatics analysis of the generated complex datasets are discussed in detail. To illustrate the concepts and the expected results of metabolomics analyses, we also present an overview of comparative metabolic profiles of drug-sensitive and drug-resistant Leishmania donovani clinical isolates.
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Lewis MD, Llewellyn MS, Gaunt MW, Yeo M, Carrasco HJ, Miles MA. Flow cytometric analysis and microsatellite genotyping reveal extensive DNA content variation in Trypanosoma cruzi populations and expose contrasts between natural and experimental hybrids. Int J Parasitol 2009; 39:1305-17. [PMID: 19393242 PMCID: PMC2731025 DOI: 10.1016/j.ijpara.2009.04.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 04/03/2009] [Accepted: 04/06/2009] [Indexed: 12/05/2022]
Abstract
Trypanosoma cruzi exhibits remarkable genetic heterogeneity. This is evident at the nucleotide level but also structurally, in the form of karyotypic variation and DNA content differences between strains. Although natural populations of T. cruzi are predominantly clonal, hybrid lineages (TcIId and TcIIe) have been identified and hybridisation has been demonstrated in vitro, raising the possibility that genetic exchange may continue to shape the evolution of this pathogen. The mechanism of genetic exchange identified in the laboratory is unusual, apparently involving fusion of diploid parents followed by genome erosion. We investigated DNA content diversity in natural populations of T. cruzi in the context of its genetic subdivisions by using flow cytometric analysis and multilocus microsatellite genotyping to determine the relative DNA content and estimate the ploidy of 54 cloned isolates. The maximum difference observed was 47.5% between strain Tu18 cl2 (TcIIb) and strain C8 cl1 (TcI), which we estimated to be equivalent to ∼73 Mb of DNA. Large DNA content differences were identified within and between discrete typing units (DTUs). In particular, the mean DNA content of TcI strains was significantly less than that for TcII strains (P < 0.001). Comparisons of hybrid DTUs TcIId/IIe with corresponding parental DTUs TcIIb/IIc indicated that natural hybrids are predominantly diploid. We also measured the relative DNA content of six in vitro-generated TcI hybrid clones and their parents. In contrast to TcIId/IIe hybrid strains these experimental hybrids comprised populations of sub-tetraploid organisms with mean DNA contents 1.65–1.72 times higher than the parental organisms. The DNA contents of both parents and hybrids were shown to be relatively stable after passage through a mammalian host, heat shock or nutritional stress. The results are discussed in the context of hybridisation mechanisms in both natural and in vitro settings.
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Dujardin JC. Structure, dynamics and function of Leishmania genome: Resolving the puzzle of infection, genetics and evolution? INFECTION GENETICS AND EVOLUTION 2009; 9:290-7. [DOI: 10.1016/j.meegid.2008.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 11/25/2008] [Accepted: 11/25/2008] [Indexed: 01/23/2023]
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Deborggraeve S, Laurent T, Espinosa D, Van der Auwera G, Mbuchi M, Wasunna M, El-Safi S, Al-Basheer AA, Arévalo J, Miranda-Verástegui C, Leclipteux T, Mertens P, Dujardin JC, Herdewijn P, Büscher P. A simplified and standardized polymerase chain reaction format for the diagnosis of leishmaniasis. J Infect Dis 2009; 198:1565-72. [PMID: 18816188 PMCID: PMC7109679 DOI: 10.1086/592509] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Background. Definite diagnosis of Leishmania infections is based on demonstration of the parasite by microscopic analysis of tissue biopsy specimens or aspirate samples. However, microscopy generally shows low sensitivity and requires invasive sampling. Methods. We describe here the development of a simple and rapid test for the detection of polymerase chain reaction-amplified Leishmania DNA. A phase 1 evaluation of the text was conducted in clinical samples from 60 nonendemic and 45 endemic control subjects and from 44 patients with confirmed cutaneous leishmaniasis (CL), 12 with mucocutaneous leishmaniasis (MCL), and 43 with visceral leishmaniasis (VL) from Peru, Kenya, and Sudan. Results. The lower detection limits of the assay are 10 fg of Leishmania DNA and 1 parasite in 180 µL of blood. The specificity was 98.3% (95% confidence interval [CI], 91.1%–99.7%) and 95.6% (95% CI, 85.2%–98.8%) for nonendemic and endemic control samples, respectively, and the sensitivity was 93.2% (95% CI, 81.8%–97.7%), 91.7% (95% CI, 64.6%–98.5%), and 86% (95% CI, 72.7%–93.4%) for lesions from patients with CL or MCL and blood from patients with VL, respectively. Conclusions. The Leishmania OligoC-TesT showed high specificity and sensitivity in clinical samples and was able to detect the parasite in samples obtained by less invasive means, such as blood, lymph, and lesion scrapings. The assay is a promising new tool for simplified and standardized molecular detection of Leishmania parasites.
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Affiliation(s)
- Stijn Deborggraeve
- Department of Parasitology, Institute of Tropical Medicine Antwerp, Antwerp, Belgium.
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Bañuls AL, Hide M, Prugnolle F. Leishmania and the leishmaniases: a parasite genetic update and advances in taxonomy, epidemiology and pathogenicity in humans. ADVANCES IN PARASITOLOGY 2007; 64:1-109. [PMID: 17499100 DOI: 10.1016/s0065-308x(06)64001-3] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Leishmaniases remain a major public health problem today despite the vast amount of research conducted on Leishmania pathogens. The biological model is genetically and ecologically complex. This paper explores the advances in Leishmania genetics and reviews population structure, taxonomy, epidemiology and pathogenicity. Current knowledge of Leishmania genetics is placed in the context of natural populations. Various studies have described a clonal structure for Leishmania but recombination, pseudo-recombination and other genetic processes have also been reported. The impact of these different models on epidemiology and the medical aspects of leishmaniases is considered from an evolutionary point of view. The role of these parasites in the expression of pathogenicity in humans is also explored. It is important to ascertain whether genetic variability of the parasites is related to the different clinical expressions of leishmaniasis. The review aims to put current knowledge of Leishmania and the leishmaniases in perspective and to underline priority questions which 'leishmaniacs' must answer in various domains: epidemiology, population genetics, taxonomy and pathogenicity. It concludes by presenting a number of feasible ways of responding to these questions.
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Affiliation(s)
- Anne-Laure Bañuls
- Institut de Recherche pour le Développement, UMR CNRS/IRD 2724, Génétique et Evolution des Maladies Infectieuses, IRD Montpellier, 911 avenue Agropolis, 34394 Montpellier cedex 5, France
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Dujardin JC, De Doncker S, Jacquet D, Bañuls AL, Balavoine M, Van Bockstaele D, Tibayrenc M, Arevalo J, Le Ray D. Clonal propagation and the fast generation of karyotype diversity: An in vitro Leishmania model. Parasitology 2006; 134:33-9. [PMID: 16978449 DOI: 10.1017/s0031182006001156] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 06/26/2006] [Accepted: 06/26/2006] [Indexed: 11/07/2022]
Abstract
In the present work we studied the karyotype stability during long-term in vitro maintenance in 3 cloned strains of Leishmania (Viannia) peruviana, Leishmania (Viannia) braziliensis and a hybrid between both species. Only the L. (V.) peruviana strain showed an unstable karyotype, even after subcloning. Four chromosomes were studied in detail, each of them characterized by homologous chromosomes of different size (heteromorphy). Variations in chromosome patterns during in vitro maintenance were rapid and discrete, involving loss of heteromorphy or appearance of additional chromosome size variants. The resulting pattern was not the same according to experimental conditions (subinoculation rate or incubation temperature), and interestingly, this was associated with differences in growth behaviour of the respective parasites. No change in total ploidy of the cells was observed by flow cytometry. We discuss several mechanisms that might account for this variation of chromosome patterns, but we favour the occurrence of aneuploidy, caused by aberrant chromosome segregation during mitosis. Our results provide insight into the generation of karyotype diversity in natural conditions and highlight the relativity of the clone concept in parasitology.
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Affiliation(s)
- J-C Dujardin
- Unit of Molecular Parasitology, Instituut voor Tropische Geneeskunde, 155 Nationalestraat, B-2000 Antwerpen, Belgium.
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Sádlová J, Volf P, Victoir K, Dujardin JC, Votýpka J. Virulent and attenuated lines of Leishmania major: DNA karyotypes and differences in metalloproteinase GP63. Folia Parasitol (Praha) 2006. [DOI: 10.14411/fp.2006.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Rotureau B, Ravel C, Couppié P, Pratlong F, Nacher M, Dedet JP, Carme B. Use of PCR-restriction fragment length polymorphism analysis to identify the main new world Leishmania species and analyze their taxonomic properties and polymorphism by application of the assay to clinical samples. J Clin Microbiol 2006; 44:459-67. [PMID: 16455899 PMCID: PMC1392689 DOI: 10.1128/jcm.44.2.459-467.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
At least 13 characterized Leishmania species are known to infect humans in South America. Five of these parasites are transmitted in the sylvatic ecotopes of the whole French Guianan territory and responsible for cutaneous leishmaniasis. For the diagnosis of cutaneous leishmaniasis, restriction fragment length polymorphism (RFLP) analyses have shown promising results. Thus, the end of the small subunit and internal transcribed spacer 1 of the rRNA genes were sequenced and targeted by PCR-RFLP analysis in the 10 main New World (NW) Leishmania species from the two subgenera. Then, the procedure was tested on 40 samples from patients with cutaneous leishmaniasis, and its results were compared with those of conventional methods. (i) The results of this simple genus-specific method were in agreement with those of previous isoenzyme analyses. (ii) This method distinguished the most medically relevant Leishmania species with only one enzyme (RsaI). (iii) This method could be performed directly on human biopsy specimens (sensitivity of 85.7%). Performing NW Leishmania species typing rapidly and easily in the field constitutes a very valuable improvement for detection of Leishmania spp. Revealing great diversity with several enzymes, this method could also be useful for taxonomic, ecological, and epidemiological studies in space and time.
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Affiliation(s)
- Brice Rotureau
- Laboratoire Hospitalo-universitaire de Parasitologie et Mycologie Médicale, Equipe EA 3593, UFR de Médecine de l'Université des Antilles et de la Guyane, Campus Saint-Denis, BP 718, 97336 Cayenne, Guyane Française
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Rotureau B, Ravel C, Nacher M, Couppié P, Curtet I, Dedet JP, Carme B. Molecular epidemiology of Leishmania (Viannia) guyanensis in French Guiana. J Clin Microbiol 2006; 44:468-73. [PMID: 16455900 PMCID: PMC1392701 DOI: 10.1128/jcm.44.2.468-473.2006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Little information is available about the genetic variability of Leishmania populations and the possible correlations with ecoepidemiological features of leishmaniases. The present study was carried out in French Guiana, a country where cutaneous leishmaniases (CL) are endemic over the whole territory. The genetic polymorphism of a nuclear sequence encompassing the end of the ribosomal small subunit and the internal transcribed spacer 1 of 265 isolates from patients with CL was examined by restriction fragment length polymorphism analysis. Genotypes based on the fingerprinting phenetic integration were compared to epidemiological, clinical, and geographical data. In agreement with previous reports, five different Leishmania species were identified, but Leishmania (Viannia) guyanensis represented 95.8% of the samples. Two distinct L. (V.) guyanensis populations were found to originate in two ecologically characterized regions. Higher lesional parasite densities and the need for additional treatments were significantly linked to genotype group I. Parasites of genotype group II were more likely to cause chronic and disseminated cutaneous forms in patients. L. (V.) guyanensis was previously said not to be very polymorphic; however, the present analysis resulted in a significant degree of discrimination among L. (V.) guyanensis isolates from diverse ecological areas and with different clinical implications.
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Affiliation(s)
- Brice Rotureau
- Laboratoire Hospitalo-universitaire de Parasitologie et Mycologie Médicale, Equipe EA 3593, UFR de Médecine de l'Université des Antilles et de la Guyane, Campus Saint-Denis, BP 718, 97336 Cayenne, Guyane Française
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Boenigk J, Pfandl K, Stadler P, Chatzinotas A. High diversity of the 'Spumella-like' flagellates: an investigation based on the SSU rRNA gene sequences of isolates from habitats located in six different geographic regions. Environ Microbiol 2005; 7:685-97. [PMID: 15819851 DOI: 10.1111/j.1462-2920.2005.00743.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We isolated 28 strains of 'Spumella-like' flagellates from different freshwater and soil habitats in Austria, People's Republic of China, Nepal, New Zealand, Uganda, Kenya, Tanzania and Hawaii by use of a modified filtration-acclimatization method. 'Spumella-like' flagellates were found in all of the samples and were often among the dominant bacterivorous flagellates in the respective environments. The small subunit ribosomal RNA (SSU rRNA) gene sequence of the isolates was determined and aligned with previously published sequences of members belonging to the Chrysophyceae sensu stricto. Phylogenetic analysis of the 28 new sequences confirmed their position within the Chrysophyceae sensu stricto and positioned them within different clades. Most of the sequences grouped within clade C and formed several subclusters separated from each other by green taxa including flagellates belonging to Ochromonas, Dinobryon, Poterioochromonas and others. All soil isolates clustered together (subcluster C1) with the soil strain Spumella elongata and the undescribed soil strain 'Spumella danica'. Aquatic isolates were affiliated with at least two branches (C2 and C3). Sequence similarity to the closest related member of the Chrysophyceae ranged between 92% and 99.6%, sequence divergence among the 'Spumella-like' flagellates was as high as 10%. We conclude that (i) the 'Spumella-like' flagellates are a diverse group both in terms of sequence dissimilarity between isolates and in terms of the number of genotypes, (ii) Spumella and Ochromonas are polyphyletic, and (iii) based on the SSU rRNA gene no biogeographical restriction of certain branches could be observed even though different ecotypes may be represented by the same genotype.
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Affiliation(s)
- Jens Boenigk
- Institute for Limnology, Austrian Academy of Sciences, Mondseestr. 9, A-5310 Mondsee, Austria.
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Victoir K, Arevalo J, De Doncker S, Barker DC, Laurent T, Godfroid E, Bollen A, Le Ray D, Dujardin JC. Complexity of the major surface protease (msp) gene organization inLeishmania (Viannia) braziliensis: evolutionary and functional implications. Parasitology 2005; 131:207-14. [PMID: 16145937 DOI: 10.1017/s0031182005007535] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The major surface protease (msp orgp63) ofLeishmaniaplays a major role in the host–parasite interaction. We analysed here the structure of the msp gene locus inLeishmania (Viannia) braziliensisand compared it to results obtained in other species. Physical mapping of cosmid contigs revealed a minimum of 37 genes per haploid genome and at least 8 different msp gene families. Within the same organism, these genes showed a nucleotide sequence varying in certain stretches from 3 to 34%, and a mosaic structure. From an evolutionary point of view, major differences were observed between subgeneraVianniaandLeishmania, both in terms of msp gene number and sequence. Within subgenusViannia, phenetic analysis revealed three clusters in which sequence variants ofL. (Viannia) braziliensisandL. (Viannia) guyanensiswere interspersed. Functional implications of our results were explored from predictedL. (Viannia) braziliensisprotein sequences: regions encoding the msp catalytic site showed a conserved sequence, while regions encoding surface domains possibly involved in the host–parasite interaction (macrophage adhesion sites and immunodominant B-cell and T-cell epitopes) were variable. We speculate that this would be an adaptive strategy of the parasite.
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Affiliation(s)
- K Victoir
- Laboratory of Molecular Parasitology, Instituut voor Tropische Geneeskunde 'Prins Leopold', 155 Nationalestraat, B-2000 Antwerpen, Belgium
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31
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Orlando TC, Rubio MAT, Sturm NR, Campbell DA, Floeter-Winter LM. Intergenic and external transcribed spacers of ribosomal RNA genes in lizard-infecting Leishmania: molecular structure and phylogenetic relationship to mammal-infecting Leishmania in the subgenus Leishmania (Leishmania). Mem Inst Oswaldo Cruz 2002; 97:695-701. [PMID: 12219138 DOI: 10.1590/s0074-02762002000500020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
To establish the relationships of the lizard- and mammal-infecting Leishmania, we characterized the intergenic spacer region of ribosomal RNA genes from L. tarentolae and L. hoogstraali. The organization of these regions is similar to those of other eukaryotes. The intergenic spacer region was approximately 4 kb in L. tarentolae and 5.5 kb in L. hoogstraali. The size difference was due to a greater number of 63-bp repetitive elements in the latter species. This region also contained another element, repeated twice, that had an inverted octanucleotide with the potential to form a stem-loop structure that could be involved in transcription termination or processing events. The ribosomal RNA gene localization showed a distinct pattern with one chromosomal band (2.2 Mb) for L. tarentolae and two (1.5 and 1.3 Mb) for L. hoogstraali. The study also showed sequence differences in the external transcribed region that could be used to distinguish lizard Leishmania from the mammalian Leishmania. The intergenic spacer region structure features found among Leishmania species indicated that lizard and mammalian Leishmania are closely related and support the inclusion of lizard-infecting species into the subgenus Sauroleishmania proposed by Saf'janova in 1982.
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Affiliation(s)
- Tereza C Orlando
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, 05508-900, Brasil
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Dujardin JC, Victoir K, De Doncker S, Guerbouj S, Arévalo J, Le Ray D. Molecular epidemiology and diagnosis of Leishmania: what have we learnt from genome structure, dynamics and function? Trans R Soc Trop Med Hyg 2002; 96 Suppl 1:S81-6. [PMID: 12055856 DOI: 10.1016/s0035-9203(02)90056-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This paper reviews our exploration of the dynamics of the Leishmania genome and its contribution to epidemiology and diagnosis. We used as a model Peruvian populations of L. (Viannia) braziliensis and L. (V.) peruviana, 2 species very close phylogenetically, but phenotypically very different in biotope and pathology. We initially focused on karyotype analysis. Our data showed that chromosomes were subject to a fast rate of evolution, and were sensitive indicators of genetic drift. Therefore, molecular karyotyping appeared an adequate tool for monitoring (i) emergence of close species, (ii) ecogeographical differentiation at the intraspecific level, and (iii) strain 'fingerprinting'. Chromosome size variation was mostly due to the number of tandemly repeated genes (rDNA, mini-exon, gp63, and cysteine proteinase genes), and could involve the deletion of unique genes (L. (V.) braziliensis-specific gp63 families). Considering the importance of these genes in parasitism, their rearrangement might have functional implications: adaptation to different environments and pleomorphic pathogenicity. Our knowledge of genome structure and dynamics was used to develop new polymerase chain reaction (PCR) techniques. Amplification of gp63 genes followed by cleavage with restriction enzymes and study of restriction fragment length polymorphism (gp63 PCR-RFLP) allowed the discrimination of all species tested, even directly in biopsies with 95% sensitivity (compared with PCR amplification of kinetoplast deoxyribonucleic acid). At the intra-specific level, RFLP was also observed and corresponded to mutations in major immunogen domains of gp63. These seem to be under strong selection pressure, and the technique should facilitate addressing how the host's immune pressure may modulate parasite population structure. Altogether, gp63 PCR-RFLP represents a significant operational improvement over the other techniques for molecular epidemiology and diagnosis: it combines sensitivity, discriminatory power and prognostic value.
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Affiliation(s)
- J C Dujardin
- Prins Leopold Instituut voor Tropische Geneeskunde, Protozoologie, 155 Nationalestraat, B-2000 Antwerpen, Belgium.
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Abstract
Eukaryotes use sexual recombination to achieve innovation and adaptation to a changing environment, a mechanism that is exceptional in Leishmania. It is postulated that asexual mechanisms contribute efficiently to parasite fitness and that sexual recombination would not be necessary for the production of a large repertoire of genotypes. The model discussed in this review used a major Leishmania glycoprotein, gp63, which is involved in host-parasite relationships. Mitotic recombination, which occurs between and within tandem repeats, amplifies genes and generates genotypic diversity. The resulting variation in the protein sequence is concentrated in surface domains, in regions spanning T-cell epitopes and B-cell epitopes and might allow immune escape.
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Affiliation(s)
- Kathleen Victoir
- Dept of Parasitology, Prins Leopold Instituut voor Tropische Geneeskunde, 155 Nationalestraat, B-2000, Antwerpen, Belgium
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Martínez-Calvillo S, Sunkin SM, Yan S, Fox M, Stuart K, Myler PJ. Genomic organization and functional characterization of the Leishmania major Friedlin ribosomal RNA gene locus. Mol Biochem Parasitol 2001; 116:147-57. [PMID: 11522348 DOI: 10.1016/s0166-6851(01)00310-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The sequence and gene organization of the ribosomal RNA (rRNA) genes of Leishmania major Friedlin (LmjF) were determined. Interestingly, the rDNA repeat unit contained a duplicated 526 bp fragment at the 3' end of the unit with two copies of the LSUepsilon rRNA gene. Our results suggested the presence of only approximately 24 copies of the rRNA unit per diploid genome in LmjF. Repetitive elements (IGSRE) of 63 bp occurred in the intergenic spacer (IGS) between the LSUepsilon and the SSU rRNA genes. Among the different rDNA units, the region containing the IGSRE fluctuated in length from approximately 1.3 to approximately 18 kb. The transcription initiation site (TIS) of the rRNA unit was localized by primer extension to 1043 bp upstream of the SSU gene and 184 bp downstream of the IGSRE. Sequence comparison among several species of Leishmania showed a high degree of conservation around the TIS. Moreover, the IGSRE also showed considerable similarity between Leishmania species. In transient transfection assays, a fragment containing the TIS directed a 164- to 178-fold increase in luciferase activity over the no-insert control, indicating the presence of a promoter within this 391 bp fragment. The LmjF promoter region was also functional in other species of Leishmania. Nuclear run-on analyses demonstrated that only the rRNA-coding strand is transcribed, downstream of this RNA polymerase I (pol I) promoter. These experiments also suggested that transcription terminates upstream of the IGSRE.
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Affiliation(s)
- S Martínez-Calvillo
- Seattle Biomedical Research Institute, 4 Nickerson Street, Seattle, WA 98109-1651, USA
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Guerbouj S, Guizani I, Speybroeck N, Le Ray D, Dujardin JC. Genomic polymorphism of Leishmania infantum: a relationship with clinical pleomorphism? INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2001; 1:49-59. [PMID: 12798050 DOI: 10.1016/s1567-1348(01)00008-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Leishmania infantum is the etiological agent of visceral (VL) and a cutaneous form (CL) of leishmaniasis around the Mediterranean Basin. In order to document the parasite genetic background corresponding to this clinical diversity, chromosome size polymorphism was analysed in 32 French isolates (18 CL and 14 VL) originating from the Cévennes and the Pyrénées Orientales (PO), and corresponding to zymodemes MON-1 and MON-29. Five chromosomes bearing tandemly repeated genes encoding for important antigens (gp63, PSA-2 and K39) or key metabolic functions (mini-exon and rDNA) were studied. Significant size variation (100-270 kbp) was observed for chromosomes bearing mini-exon, PSA-2 and rDNA genes, which involved variation in copy number of corresponding genes. The two other chromosomes showed smaller size-variation and did not involve dosage of gp63 and K39 genes. Chromosomal size showed correlation with geography and clinical origin: (i) chromosome 2 (mini-exon) was found to be significantly smaller in the PO; (ii) chromosomes 12 (PSA-2) and 27 (rDNA) were significantly smaller in the strictly cutaneous MON-29 isolates. Gene rearrangements and their synergistic effects on the phenotypic expression of the parasite are discussed.
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Affiliation(s)
- S Guerbouj
- Laboratoire d' Epidémiologie et Ecologie Parasitaire, Institut Pasteur de Tunis, 13 Place Pasteur BP74, 1002 Tunis, Belvédère, Tunisia
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Fredslund L, Ekelund F, Jacobsen CS, Johnsen K. Development and application of a most-probable-number-pcr assay to quantify flagellate populations in soil samples. Appl Environ Microbiol 2001; 67:1613-8. [PMID: 11282613 PMCID: PMC92777 DOI: 10.1128/aem.67.4.1613-1618.2001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This paper reports on the first successful molecular detection and quantification of soil protozoa. Quantification of heterotrophic flagellates and naked amoebae in soil has traditionally relied on dilution culturing techniques, followed by most-probable-number (MPN) calculations. Such methods are biased by differences in the culturability of soil protozoa and are unable to quantify specific taxonomic groups, and the results are highly dependent on the choice of media and the skills of the microscopists. Successful detection of protozoa in soil by DNA techniques requires (i) the development and validation of DNA extraction and quantification protocols and (ii) the collection of sufficient sequence data to find specific protozoan 18S ribosomal DNA sequences. This paper describes the development of an MPN-PCR assay for detection of the common soil flagellate Heteromita globosa, using primers targeting a 700-bp sequence of the small-subunit rRNA gene. The method was tested by use of gnotobiotic laboratory microcosms with sterile tar-contaminated soil inoculated with the bacterium Pseudomonas putida OUS82 UCB55 as prey. There was satisfactory overall agreement between H. globosa population estimates obtained by the PCR assay and a conventional MPN assay in the three soils tested.
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Affiliation(s)
- L Fredslund
- Geological Survey of Denmark and Greenland, Department of Geochemistry, Thoravej 8, DK-2400 Copenhagen NV, Denmark
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Lachaud L, Chabbert E, Dubessay P, Reynes J, Lamothe J, Bastien P. Comparison of various sample preparation methods for PCR diagnosis of visceral leishmaniasis using peripheral blood. J Clin Microbiol 2001; 39:613-7. [PMID: 11158116 PMCID: PMC87785 DOI: 10.1128/jcm.39.2.613-617.2001] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We have compared various sample preparation methods for the PCR diagnosis of visceral leishmaniasis (VL) using peripheral blood samples and tested the influence of these protocols upon sensitivity. Four methods of lysis-DNA extraction were used with two types of blood samples: whole blood (WB) and buffy coat (BC). Comparisons were first carried out with seeded samples at various parasite concentrations. At high concentrations (> or = 1,000 parasites/ml), there were no significant differences in PCR sensitivity among the methods tested. At concentrations of < or = 100 parasites/ml, proteinase K (PK)-based methods proved clearly superior to guanidine-EDTA-based methods. Moreover, a 10-fold increase in sensitivity was observed for BC over that for WB. Thus, the best sensitivity was obtained with the BC prepared with PK-based methods. With this combination, the PCR reliably detected 10 parasites/ml but was inconsistent when the sample contained 1 parasite/ml of blood. The methods that yielded the highest sensitivities were evaluated with seven dogs and four human VL patients. Again, the utilization of the BC prepared with PK-based methods gave the best results. The optimization of each step of the assay (sample preparation, DNA extraction, and PCR conditions) yielded a highly sensitive tool for the diagnosis of VL using patient blood, thus avoiding more invasive diagnostic procedures and allowing the detection of low parasitemia during posttherapeutic follow-up.
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Affiliation(s)
- L Lachaud
- Laboratoire de Parasitologie-Mycologie et Centre National de Référence sur les Leishmanioses, Centre Hospitalier Universitaire, Faculté de Médecine, Montpellier, France
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38
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Schnare MN, Collings JC, Spencer DF, Gray MW. The 28S-18S rDNA intergenic spacer from Crithidia fasciculata: repeated sequences, length heterogeneity, putative processing sites and potential interactions between U3 small nucleolar RNA and the ribosomal RNA precursor. Nucleic Acids Res 2000; 28:3452-61. [PMID: 10982863 PMCID: PMC110749 DOI: 10.1093/nar/28.18.3452] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2000] [Revised: 07/17/2000] [Accepted: 07/28/2000] [Indexed: 11/12/2022] Open
Abstract
In Crithidia fasciculata, the ribosomal RNA (rRNA) gene repeats range in size from approximately 11 to 12 kb. This length heterogeneity is localized to a region of the intergenic spacer (IGS) that contains tandemly repeated copies of a 19mer sequence. The IGS also contains four copies of an approximately 55 nt repeat that has an internal inverted repeat and is also present in the IGS of Leishmania species. We have mapped the C.fasciculata transcription initiation site as well as two other reverse transcriptase stop sites that may be analogous to the A0 and A' pre-rRNA processing sites within the 5' external transcribed spacer (ETS) of other eukaryotes. Features that could influence processing at these sites include two stretches of conserved primary sequence and three secondary structure elements present in the 5' ETS. We also characterized the C.fasciculata U3 snoRNA, which has the potential for base-pairing with pre-rRNA sequences. Finally, we demonstrate that biosynthesis of large subunit rRNA in both C. fasciculata and Trypanosoma brucei involves 3'-terminal addition of three A residues that are not present in the corresponding DNA sequences.
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MESH Headings
- Animals
- Base Pairing
- Base Sequence
- Conserved Sequence
- Crithidia fasciculata/genetics
- Crithidia fasciculata/metabolism
- DNA, Protozoan/genetics
- DNA, Protozoan/metabolism
- DNA, Ribosomal/genetics
- DNA, Ribosomal/metabolism
- Genetic Heterogeneity
- Molecular Sequence Data
- Nucleic Acid Conformation
- RNA Precursors/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Ribosomal/metabolism
- RNA, Small Nucleolar/chemistry
- RNA, Small Nucleolar/genetics
- RNA, Small Nucleolar/metabolism
- Repetitive Sequences, Nucleic Acid
- Restriction Mapping
- Sequence Alignment
- Sequence Analysis, DNA
- Trypanosoma brucei brucei/genetics
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Affiliation(s)
- M N Schnare
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
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Dujardin JC, Henriksson J, Victoir K, Brisse S, Gamboa D, Arevalo J, Le Ray D. Genomic rearrangements in trypanosomatids: an alternative to the "one gene" evolutionary hypotheses? Mem Inst Oswaldo Cruz 2000; 95:527-34. [PMID: 10904411 DOI: 10.1590/s0074-02762000000400015] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Most molecular trees of trypanosomatids are based on point mutations within DNA sequences. In contrast, there are very few evolutionary studies considering DNA (re) arrangement as genetic characters. Waiting for the completion of the various parasite genome projects, first information may already be obtained from chromosome size-polymorphism, using the appropriate algorithms for data processing. Three illustrative models are presented here. First, the case of Leishmania (Viannia) braziliensis/L. (V.) peruviana is described. Thanks to a fast evolution rate (due essentially to amplification/deletion of tandemly repeated genes), molecular karyotyping seems particularly appropriate for studying recent evolutionary divergence, including eco-geographical diversification. Secondly, karyotype evolution is considered at the level of whole genus Leishmania. Despite the fast chromosome evolution rate, there is qualitative congruence with MLEE- and RAPD-based evolutionary hypotheses. Significant differences may be observed between major lineages, likely corresponding to major and less frequent rearrangements (fusion/fission, translocation). Thirdly, comparison is made with Trypanosoma cruzi. Again congruence is observed with other hypotheses and major lineages are delineated by significant chromosome rearrangements. The level of karyotype polymorphism within that "species" is similar to the one observed in "genus" Leishmania. The relativity of the species concept among these two groups of parasites is discussed.
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Affiliation(s)
- J C Dujardin
- Prins Leopold Instituut voor Tropische Geneeskunde, Belgium.
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40
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van Leeuwen F, Kieft R, Cross M, Borst P. Tandemly repeated DNA is a target for the partial replacement of thymine by beta-D-glucosyl-hydroxymethyluracil in Trypanosoma brucei. Mol Biochem Parasitol 2000; 109:133-45. [PMID: 10960172 DOI: 10.1016/s0166-6851(00)00247-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the DNA of African trypanosomes a small fraction of thymine is replaced by the modified base beta-D-glucosyl-hydroxymethyluracil (J). The function of this large base is unknown. The presence of J in the silent variant surface glycoprotein gene expression sites and the lack of J in the transcribed expression site indicates that DNA modification might play a role in control of gene repression. However, the abundance of J in the long telomeric repeat tracts and in subtelomeric arrays of simple repeats suggests that J may also have specific functions in repetitive DNA. We have now analyzed chromosome-internal repetitive sequences in the genome of Trypanosoma brucei and found J in the minichromosomal 177-bp repeats, in the long arrays of 5S RNA gene repeats, and in the spliced-leader RNA gene repeats. No J was found in the rDNA locus or in dispersed repetitive transposon-like elements. Remarkably, the rDNA of T. brucei is not organized in long arrays of tandem repeats, as in many other eukaryotes. T. brucei contains only approximately 15-20 rDNA repeat units that are divided over six to seven chromosomes. Our results show that J is present in many tandemly repeated sequences, either at a telomere or chromosome internal. The presence of J might help to stabilize the long arrays of repeats in the genome.
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MESH Headings
- Animals
- DNA Transposable Elements/genetics
- DNA, Protozoan/analysis
- DNA, Protozoan/chemistry
- DNA, Protozoan/genetics
- DNA, Ribosomal/analysis
- DNA, Ribosomal/genetics
- Genes, Protozoan
- Genes, rRNA
- Glucosides/analysis
- RNA, Ribosomal, 5S/genetics
- RNA, Spliced Leader/genetics
- Tandem Repeat Sequences/genetics
- Telomere/genetics
- Thymine/analysis
- Trypanosoma brucei brucei/chemistry
- Trypanosoma brucei brucei/genetics
- Uracil/analogs & derivatives
- Uracil/analysis
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Affiliation(s)
- F van Leeuwen
- Division of Molecular Biology and Centre of Biomedical Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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Sunkin SM, Kiser P, Myler PJ, Stuart K. The size difference between leishmania major friedlin chromosome one homologues is localized to sub-telomeric repeats at one chromosomal end. Mol Biochem Parasitol 2000; 109:1-15. [PMID: 10924752 DOI: 10.1016/s0166-6851(00)00215-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Leishmania species are members of the evolutionarily ancient protozoan order Kinetoplastidae and are important human pathogens. The Leishmania genome is relatively small (approximately 34 Mbp) and is distributed among 36 chromosome pairs, ranging in size from 0.3 to 2.5 Mbp. The smallest chromosome of Leishmania major Friedlin, chrl, consists of three homologues which differ in size by approximately 29 kb. Previous sequence and Southern analyses of all three homologues reveal a conserved chromosomal core, consisting of coding and adjacent 'non-informational' sequence. Here we show the size difference between homologues is largely restricted to variation in both the number and content of several sub-telomeric repetitive elements localized on one chromosomal end. These repetitive elements also occur on other chromosomes, but some are more dispersed in the Leishmania genome than others.
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Affiliation(s)
- S M Sunkin
- Seattle Biomedical Research Institute, WA 98109-1651, USA
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42
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Bañuls AL, Dujardin JC, Guerrini F, De Doncker S, Jacquet D, Arevalo J, Noël S, Le Ray D, Tibayrenc M. Is Leishmania (Viannia) peruviana a distinct species? A MLEE/RAPD evolutionary genetics answer. J Eukaryot Microbiol 2000; 47:197-207. [PMID: 10847336 DOI: 10.1111/j.1550-7408.2000.tb00039.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A set of 38 Leishmania stocks from the Andean valleys of Peru was characterized by both Multilocus Enzyme Electrophoresis (MLEE) and Random Amplified Polymorphic DNA (RAPD). Data were analyzed in terms of taxonomy and evolutionary genetics. Synapomorphic MLEE and RAPD characters, clear-cut clustering, and strong agreement between the phylogenies inferred from either MLEE or RAPD supported the view that Leishmania (Viannia) peruviana and Leishmania (Viannia) braziliensis correspond to two closely related, but distinct monophyletic lines (clades) and can therefore be considered as "discrete typing units" (DTUs). The question whether the L. (V.) peruxviana DTU deserves species status is dependent upon the desirability of it, in terms of epidemiological and medical relevance. A previous Orthogonal Field Alternating Gel Electrophoresis (OFAGE) analysis of the same L. (V.) peruviana isolates was published by Dujardin et al. (1995b). The data from the different markers (i.e. MLEE, RAPD and OFAGE) were compared by population genetics analysis. RAPD and OFAGE provided divergent results, since RAPD showed a strong linkage disequilibrium whereas OFAGE revealed no apparent departure from panmictic expectation. MLEE showed no linkage disequilibrium. Nevertheless, contrary to OFAGE, this is most probably explainable by the limited variability revealed by this marker in L. (V.) peruviana (statistical type II error). RAPD data were consistent with the hypothesis that the present L. (V.) peruviana sample displays a basically clonal population structure with limited or no genetic exchange. Disagreement between RAPD and OFAGE can be explained either by accumulation of chromosomal rearrangements due to amplification/deletion of repeated sequences, or by pseudo-recombinational events.
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Affiliation(s)
- A L Bañuls
- Centre d'Etudes sur le Polymorphisme des Microorganismes (CEPM), Unité Mixte de Recherche Centre Nationale de la Recherche Scientifique (CNRS)/Institut de Recherche pour le Developpement (IRD), Montpellier, France.
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Lachaud L, Dereure J, Chabbert E, Reynes J, Mauboussin JM, Oziol E, Dedet JP, Bastien P. Optimized PCR using patient blood samples for diagnosis and follow-up of visceral Leishmaniasis, with special reference to AIDS patients. J Clin Microbiol 2000; 38:236-40. [PMID: 10618093 PMCID: PMC88701 DOI: 10.1128/jcm.38.1.236-240.2000] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We developed a highly sensitive PCR method that enables the diagnosis and posttherapeutic follow-up of visceral leishmaniasis with patient blood. The PCR assay was thoroughly optimized by successive procedural refinements to increase its sensitivity and specificity. It was compared to in vitro cultivation as well as to direct examination of bone marrow and to serology. Two hundred thirty-seven patients presenting with clinical signs compatible with visceral leishmaniasis were included in the study. Thirty-six were diagnosed as having Mediterranean visceral leishmaniasis (MVL). Twenty-three of them, including 19 AIDS patients, were monitored during and after treatment over a period from 2 weeks to 3 years. Our PCR assay proved more sensitive than in vitro cultivation, direct examination, and serology for all patients. It is simple and can be adapted to routine hospital diagnostic procedures. For the primary diagnosis of MVL, the sensitivity of PCR versus that of cultivation was 97 versus 55% with peripheral blood and 100 versus 81% with bone marrow samples. Regarding posttherapeutic follow-up, overall, 48% of positive samples were detected by PCR only. Seven patients presented with a clinical relapse during the study; six relapses were detected at first by PCR only, sometimes a few weeks before the reappearance of signs or symptoms. We conclude that an optimized and well-mastered PCR assay with a peripheral blood sample is sufficient to provide a secure diagnosis for all immunocompromised patients and most immunocompetent patients. We also suggest systematic posttherapeutic monitoring by PCR with peripheral blood for immunocompromised patients.
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Affiliation(s)
- L Lachaud
- Laboratoire de Parasitologie-Mycologie et Centre National de Référence sur les Leishmanioses, Centre Hospitalier-Universitaire, 34000 Montpellier, France
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Kebede A, De Doncker S, Arevalo J, Le Ray D, Dujardin JC. Size-polymorphism of mini-exon gene-bearing chromosomes among natural populations of Leishmania, subgenus Viannia. Int J Parasitol 1999; 29:549-57. [PMID: 10428631 DOI: 10.1016/s0020-7519(99)00010-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In order to explore genomic plasticity at the level of the mini-exon gene-bearing chromosome in natural populations of Leishmania, the molecular karyotype of 84 Leishmania stocks belonging to subgenus Viannia, originating mostly from Peru and Bolivia, and differing according to eco-geographical and clinical parameters, was resolved and hybridised with a mini-exon probe. The results suggest that size variation of the mini-exon gene-bearing chromosome is frequent and important (up to 245-kb size-difference), and partially involves variation (up to 50%) in copy number of mini-exon genes. There is no significant size-difference between mini-exon-bearing chromosomes of Peruvian and Bolivian populations of cutaneous and mucosal isolates of Leishmania (Viannia) braziliensis, but there is between eco-geographical populations of Leishmania (Viannia) peruviana. Leishmania (V.) peruviana presented a significantly smaller mini-exon-bearing chromosome than the other species of subgenus Viannia. The contrast between the general chromosome size heterogeneity and the homogeneity observed in some Peruvian Andean areas is discussed in terms of selective pressure.
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Affiliation(s)
- A Kebede
- Laboratory of Protozoology, Institute of Tropical Medicine Prince Leopold, Antwerp, Belgium
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Torrico MC, De Doncker S, Arevalo J, Le Ray D, Dujardin JC. In vitro promastigote fitness of putative Leishmania (Viannia) braziliensis/Leishmania (Viannia) peruviana hybrids. Acta Trop 1999; 72:99-110. [PMID: 9924965 DOI: 10.1016/s0001-706x(98)00076-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In order to initiate studies on the phenotypic properties of hybrids vs. their putative parents, the in vitro growth behaviour of promastigotes was compared for 15 stocks characterised as Leishmania (Viannia) braziliensis, Leishmania (Viannia) peruviana and putative hybrids (isolated from the Eastern Andean valley of Huanuco, Peru). Five sets of three stocks, each set including a L.(V.)braziliensis, a L.(V.)peruviana and a putative hybrid, were constituted randomly and counted daily close to isolation from man (ten to 18 subcultures). Hybrids and L.(V.)peruviana presented similar growth characteristics, and they displayed a growth capacity (growth rate and cell density at stationary phase) significantly lower than the one of L.(V.)braziliensis. Following prolonged in vitro maintenance of one of the sets, the hybrid kept its lower growth capacity. The contrast between the difficulty to grow in vitro these putative hybrids, and their high isolation rate from natural populations is discussed.
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Affiliation(s)
- M C Torrico
- Laboratory of Protozoology, Institute of Tropical Medicine Prince Leopold, Antwerpen, Belgium
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