151
|
Wendte JM, Miller MA, Lambourn DM, Magargal SL, Jessup DA, Grigg ME. Self-mating in the definitive host potentiates clonal outbreaks of the apicomplexan parasites Sarcocystis neurona and Toxoplasma gondii. PLoS Genet 2010; 6:e1001261. [PMID: 21203443 PMCID: PMC3009688 DOI: 10.1371/journal.pgen.1001261] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 11/23/2010] [Indexed: 12/24/2022] Open
Abstract
Tissue-encysting coccidia, including Toxoplasma gondii and Sarcocystis neurona, are heterogamous parasites with sexual and asexual life stages in definitive and intermediate hosts, respectively. During its sexual life stage, T. gondii reproduces either by genetic out-crossing or via clonal amplification of a single strain through self-mating. Out-crossing has been experimentally verified as a potent mechanism capable of producing offspring possessing a range of adaptive and virulence potentials. In contrast, selfing and other life history traits, such as asexual expansion of tissue-cysts by oral transmission among intermediate hosts, have been proposed to explain the genetic basis for the clonal population structure of T. gondii. In this study, we investigated the contributing roles self-mating and sexual recombination play in nature to maintain clonal population structures and produce or expand parasite clones capable of causing disease epidemics for two tissue encysting parasites. We applied high-resolution genotyping against strains isolated from a T. gondii waterborne outbreak that caused symptomatic disease in 155 immune-competent people in Brazil and a S. neurona outbreak that resulted in a mass mortality event in Southern sea otters. In both cases, a single, genetically distinct clone was found infecting outbreak-exposed individuals. Furthermore, the T. gondii outbreak clone was one of several apparently recombinant progeny recovered from the local environment. Since oocysts or sporocysts were the infectious form implicated in each outbreak, the expansion of the epidemic clone can be explained by self-mating. The results also show that out-crossing preceded selfing to produce the virulent T. gondii clone. For the tissue encysting coccidia, self-mating exists as a key adaptation potentiating the epidemic expansion and transmission of newly emerged parasite clones that can profoundly shape parasite population genetic structures or cause devastating disease outbreaks. The parasites Toxoplasma gondii and Sarcocystis neurona have lifecycles that include a sexual stage in a definitive host and an asexual stage in intermediate hosts. For T. gondii, laboratory studies have demonstrated that the sexual stage can serve the dual purpose of producing new, virulent genotypes through recombination and promoting expansion of single clones via self-mating. Self-mating and other life history traits of T. gondii, including transmission of asexual stages among intermediate hosts, are assumed to account for the clonal population genetic structure of this organism. However, the relative contributions of sexual recombination and self-mating verses other life history traits in causing disease outbreaks or in shaping Toxoplasma's population genetic structure have not been verified in nature, nor have these traits been extensively examined in related parasites. To address this knowledge gap, we conducted population genetic analyses on T. gondii and S. neurona strains isolated from naturally occurring outbreaks affecting humans and sea otters, respectively. Our results identify self-mating as a key trait potentiating disease outbreaks through the rapid amplification of a single clone into millions of infectious units. Selfing is likely a key adaptation for enhancing transmission of recently emerged, recombinant clones and reshaping population genetic structures among the tissue-cyst coccidia.
Collapse
Affiliation(s)
- Jered M. Wendte
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Veterinary Pathobiology, Oklahoma State University Center for Veterinary Health Sciences, Stillwater, Oklahoma, United States of America
- Howard Hughes Medical Institute–National Institutes of Health Research Scholars Program, Bethesda, Maryland, United States of America
| | - Melissa A. Miller
- Marine Wildlife Veterinary Care and Research Center (CDFG-OSPR), Santa Cruz, California, United States of America
| | - Dyanna M. Lambourn
- Washington Department of Fish and Wildlife, Lakewood, Washington, United States of America
| | - Spencer L. Magargal
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David A. Jessup
- Marine Wildlife Veterinary Care and Research Center (CDFG-OSPR), Santa Cruz, California, United States of America
| | - Michael E. Grigg
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Veterinary Pathobiology, Oklahoma State University Center for Veterinary Health Sciences, Stillwater, Oklahoma, United States of America
- * E-mail:
| |
Collapse
|
152
|
Ocaña-Mayorga S, Llewellyn MS, Costales JA, Miles MA, Grijalva MJ. Sex, subdivision, and domestic dispersal of Trypanosoma cruzi lineage I in southern Ecuador. PLoS Negl Trop Dis 2010; 4:e915. [PMID: 21179502 PMCID: PMC3001902 DOI: 10.1371/journal.pntd.0000915] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 11/15/2010] [Indexed: 11/25/2022] Open
Abstract
Background Molecular epidemiology at the community level has an important guiding role in zoonotic disease control programmes where genetic markers are suitably variable to unravel the dynamics of local transmission. We evaluated the molecular diversity of Trypanosoma cruzi, the etiological agent of Chagas disease, in southern Ecuador (Loja Province). This kinetoplastid parasite has traditionally been a paradigm for clonal population structure in pathogenic organisms. However, the presence of naturally occurring hybrids, mitochondrial introgression, and evidence of genetic exchange in the laboratory question this dogma. Methodology/Principal Findings Eighty-one parasite isolates from domiciliary, peridomiciliary, and sylvatic triatomines and mammals were genotyped across 10 variable microsatellite loci. Two discrete parasite populations were defined: one predominantly composed of isolates from domestic and peridomestic foci, and another predominantly composed of isolates from sylvatic foci. Spatial genetic variation was absent from the former, suggesting rapid parasite dispersal across our study area. Furthermore, linkage equilibrium between loci, Hardy-Weinberg allele frequencies at individual loci, and a lack of repeated genotypes are indicative of frequent genetic exchange among individuals in the domestic/peridomestic population. Conclusions/Significance These data represent novel population-level evidence of an extant capacity for sex among natural cycles of T. cruzi transmission. As such they have dramatic implications for our understanding of the fundamental genetics of this parasite. Our data also elucidate local disease transmission, whereby passive anthropogenic domestic mammal and triatomine dispersal across our study area is likely to account for the rapid domestic/peridomestic spread of the parasite. Finally we discuss how this, and the observed subdivision between sympatric sylvatic and domestic/peridomestic foci, can inform efforts at Chagas disease control in Ecuador. Trypanosoma cruzi is transmitted by blood sucking insects known as triatomines. This protozoan parasite commonly infects wild and domestic mammals in South and Central America. However, triatomines also transmit the parasite to people, and human infection with T. cruzi is known as Chagas disease, a major public health concern in Latin America. Understanding the complex dynamics of parasite spread between wild and domestic environments is essential to design effective control measures to prevent the spread of Chagas disease. Here we describe T. cruzi genetic diversity and population dynamics in southern Ecuador. Our findings indicate that the parasite circulates in two largely independent cycles: one corresponding to the sylvatic environment and one related to the domestic/peridomestic environment. Furthermore, our data indicate that human activity might promote parasite dispersal among communties. This information is the key for the design of control programmes in Southern Ecuador. Finally, we have encountered evidence of a sexual reproductive mode in the domestic T. cruzi population, which constitutes a new and intriguing finding with regards to the biology of this parasite.
Collapse
Affiliation(s)
- Sofía Ocaña-Mayorga
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | | | | | | | | |
Collapse
|
153
|
Ramírez JD, Guhl F, Rendón LM, Rosas F, Marin-Neto JA, Morillo CA. Chagas cardiomyopathy manifestations and Trypanosoma cruzi genotypes circulating in chronic Chagasic patients. PLoS Negl Trop Dis 2010; 4:e899. [PMID: 21152056 PMCID: PMC2994916 DOI: 10.1371/journal.pntd.0000899] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Accepted: 10/29/2010] [Indexed: 11/18/2022] Open
Abstract
Chagas disease caused by Trypanosoma cruzi is a complex disease that is endemic and an important problem in public health in Latin America. The T. cruzi parasite is classified into six discrete taxonomic units (DTUs) based on the recently proposed nomenclature (TcI, TcII, TcIII, TcIV, TcV and TcVI). The discovery of genetic variability within TcI showed the presence of five genotypes (Ia, Ib, Ic, Id and Ie) related to the transmission cycle of Chagas disease. In Colombia, TcI is more prevalent but TcII has also been reported, as has mixed infection by both TcI and TcII in the same Chagasic patient. The objectives of this study were to determine the T. cruzi DTUs that are circulating in Colombian chronic Chagasic patients and to obtain more information about the molecular epidemiology of Chagas disease in Colombia. We also assessed the presence of electrocardiographic, radiologic and echocardiographic abnormalities with the purpose of correlating T. cruzi genetic variability and cardiac disease. Molecular characterization was performed in Colombian adult chronic Chagasic patients based on the intergenic region of the mini-exon gene, the 24Sα and 18S regions of rDNA and the variable region of satellite DNA, whereby the presence of T.cruzi I, II, III and IV was detected. In our population, mixed infections also occurred, with TcI-TcII, TcI-TcIII and TcI-TcIV, as well as the existence of the TcI genotypes showing the presence of genotypes Ia and Id. Patients infected with TcI demonstrated a higher prevalence of cardiac alterations than those infected with TcII. These results corroborate the predominance of TcI in Colombia and show the first report of TcIII and TcIV in Colombian Chagasic patients. Findings also indicate that Chagas cardiomyopathy manifestations are more correlated with TcI than with TcII in Colombia.
Collapse
Affiliation(s)
- Juan David Ramírez
- Centro de investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Facultad de Ciencias, Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, Colombia
| | - Felipe Guhl
- Centro de investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Facultad de Ciencias, Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, Colombia
| | - Lina María Rendón
- Centro de investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Facultad de Ciencias, Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, Colombia
| | - Fernando Rosas
- Electrofisiología, Clínica Abood Shaio, Bogotá, Colombia
| | - Jose A. Marin-Neto
- Cardiology Division, Internal Medicine Department, Medical School of Ribeirao Preto, Universidad de Sao Paulo, Sao Paulo, Brazil
| | - Carlos A. Morillo
- Department of Medicine, Cardiology Division, McMaster University, PHRI-HHSC, Hamilton, Ontario, Canada
| |
Collapse
|
154
|
Phylogenetic character mapping of proteomic diversity shows high correlation with subspecific phylogenetic diversity in Trypanosoma cruzi. Proc Natl Acad Sci U S A 2010; 107:20411-6. [PMID: 21059959 DOI: 10.1073/pnas.1015496107] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We performed a phylogenetic character mapping on 26 stocks of Trypanosoma cruzi, the parasite responsible for Chagas disease, and 2 stocks of the sister taxon T. cruzi marinkellei to test for possible associations between T. cruzi-subspecific phylogenetic diversity and levels of protein expression, as examined by proteomic analysis and mass spectrometry. We observed a high level of correlation (P < 10(-4)) between genetic distance, as established by multilocus enzyme electrophoresis, and proteomic dissimilarities estimated by proteomic Euclidian distances. Several proteins were found to be specifically associated to T. cruzi phylogenetic subdivisions (discrete typing units). This study explores the previously uncharacterized links between infraspecific phylogenetic diversity and gene expression in a human pathogen. It opens the way to searching for new vaccine and drug targets and for identification of specific biomarkers at the subspecific level of pathogens.
Collapse
|
155
|
Abstract
Sexual reproduction enables eukaryotic organisms to reassort genetic diversity and purge deleterious mutations, producing better-fit progeny. Sex arose early and pervades eukaryotes. Fungal and parasite pathogens once thought asexual have maintained cryptic sexual cycles, including unisexual or parasexual reproduction. As pathogens become niche and host adapted, sex appears to specialize to promote inbreeding and clonality yet maintain outcrossing potential. During self-fertile sexual modes, sex itself may generate genetic diversity de novo. Mating-type loci govern fungal sexual identity; how parasites establish sexual identity is unknown. Comparing and contrasting fungal and parasite sex promises to reveal how microbial pathogens evolved and are evolving.
Collapse
Affiliation(s)
- Joseph Heitman
- Department of Molecular Genetics and Microbiology, Center for Microbial Pathogenesis, Duke University Medical Center, Durham, NC 27710, USA.
| |
Collapse
|
156
|
Batista M, Marchini FK, Celedon PAF, Fragoso SP, Probst CM, Preti H, Ozaki LS, Buck GA, Goldenberg S, Krieger MA. A high-throughput cloning system for reverse genetics in Trypanosoma cruzi. BMC Microbiol 2010; 10:259. [PMID: 20942965 PMCID: PMC3020659 DOI: 10.1186/1471-2180-10-259] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 10/13/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The three trypanosomatids pathogenic to men, Trypanosoma cruzi, Trypanosoma brucei and Leishmania major, are etiological agents of Chagas disease, African sleeping sickness and cutaneous leishmaniasis, respectively. The complete sequencing of these trypanosomatid genomes represented a breakthrough in the understanding of these organisms. Genome sequencing is a step towards solving the parasite biology puzzle, as there are a high percentage of genes encoding proteins without functional annotation. Also, technical limitations in protein expression in heterologous systems reinforce the evident need for the development of a high-throughput reverse genetics platform. Ideally, such platform would lead to efficient cloning and compatibility with various approaches. Thus, we aimed to construct a highly efficient cloning platform compatible with plasmid vectors that are suitable for various approaches. RESULTS We constructed a platform with a flexible structure allowing the exchange of various elements, such as promoters, fusion tags, intergenic regions or resistance markers. This platform is based on Gateway® technology, to ensure a fast and efficient cloning system. We obtained plasmid vectors carrying genes for fluorescent proteins (green, cyan or yellow), and sequences for the c-myc epitope, and tandem affinity purification or polyhistidine tags. The vectors were verified by successful subcellular localization of two previously characterized proteins (TcRab7 and PAR 2) and a putative centrin. For the tandem affinity purification tag, the purification of two protein complexes (ribosome and proteasome) was performed. CONCLUSIONS We constructed plasmids with an efficient cloning system and suitable for use across various applications, such as protein localization and co-localization, protein partner identification and protein expression. This platform also allows vector customization, as the vectors were constructed to enable easy exchange of its elements. The development of this high-throughput platform is a step closer towards large-scale trypanosome applications and initiatives.
Collapse
Affiliation(s)
- Michel Batista
- Instituto Carlos Chagas, FIOCRUZ, Curitiba, Parana, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|
157
|
Abstract
The majority of individuals in the chronic phase of Chagas disease are asymptomatic (indeterminate form, IF). Each year, approximately 3% of them develop lesions in the heart or gastrointestinal tract. Cardiomyopathy (CCHD) is the most severe manifestation of Chagas disease. The factors that determine the outcome of the infection are unknown, but certainly depend on complex interactions amongst the genetic make-up of the parasite, the host immunogenetic background and environment. In a previous study we verified that the maxicircle gene NADH dehydrogenase (mitochondrial complex I) subunit 7 (ND7) from IF isolates had a 455 bp deletion compared with the wild type (WT) ND7 gene from CCHD strains. We proposed that ND7 could constitute a valuable target for PCR assays in the differential diagnosis of the infective strain. In the present study we evaluated this hypothesis by examination of ND7 structure in parasites from 75 patients with defined pathologies, from Southeast Brazil. We also analysed the structure of additional mitochondrial genes (ND4/CR4, COIII and COII) since the maxicircle is used for clustering Trypanosoma cruzi strains into three clades/haplogroups. We conclude that maxicircle genes do not discriminate parasite populations which induce IF or CCHD forms. Interestingly, the great majority of the analysed isolates belong to T. cruzi II (discrete typing unit, (DTU) IIb) genotype. This scenario is at variance with the prevalence of hybrid (DTU IId) human isolates in Bolivia, Chile and Argentina. The distribution of WT and deleted ND7 and ND4 genes in T. cruzi strains suggests that mutations in the two genes occurred in different ancestrals in the T. cruzi II cluster, allowing the identification of at least three mitochondrial sub-lineages within this group. The observation that T. cruzi strains accumulate mutations in several genes coding for complex I subunits favours the hypothesis that complex I may have a limited activity in this parasite.
Collapse
|
158
|
Câmara ACJ, Varela-Freire AA, Valadares HMS, Macedo AM, D'Avila DA, Machado CR, Lages-Silva E, Chiari E, Galvão LMC. Genetic analyses of Trypanosoma cruzi isolates from naturally infected triatomines and humans in northeastern Brazil. Acta Trop 2010; 115:205-11. [PMID: 20303924 DOI: 10.1016/j.actatropica.2010.03.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 03/04/2010] [Accepted: 03/11/2010] [Indexed: 11/17/2022]
Abstract
Trypanosoma cruzi genetic diversity was investigated in 25 isolates (vectors and humans) from the semiarid zone of the State of Rio Grande do Norte, Brazil. Molecular markers (3' region of the 24Salpha rRNA; mitochondrial cytochrome oxidase subunit 2 (COII) gene; spliced leader intergenic region (SL-IR) gene; allelic size microsatellite polymorphism) identified 56% TcIII (100% Panstrongyluslutzi; 50% Triatomabrasiliensis); 40% TcII (91.7% humans; 50% T. brasiliensis) and 4% TcI (human). Microsatellite analysis revealed monoclonal and heterozygous patterns on one or more microsatellite loci in 64% of T. cruzi isolates (92.3% triatomines; 33.3% humans) and 36% putative polyclonal populations (66.7% humans; 7.7% triatomines) by loci SCLE10, SCLE11, TcTAT20, TcAAAT6, all belonging to TcII. Identical T. cruzi polyclonal profiles (88.9%) were detected, mostly from humans. The adaptative natural plasticity of TcII and TcIII and their potential for maintaining human infection in T. brasiliensis were confirmed. Intraspecific and phylogenetic T. cruzi diversity in the sylvatic and domestic transmission cycles in this specific region will provide exclusive control strategies.
Collapse
Affiliation(s)
- A C J Câmara
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
159
|
Trypanosoma brucei: two steps to spread out from Africa. Trends Parasitol 2010; 26:424-7. [DOI: 10.1016/j.pt.2010.05.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 05/21/2010] [Accepted: 05/24/2010] [Indexed: 11/21/2022]
|
160
|
Lescure FX, Le Loup G, Freilij H, Develoux M, Paris L, Brutus L, Pialoux G. Chagas disease: changes in knowledge and management. THE LANCET. INFECTIOUS DISEASES 2010; 10:556-70. [PMID: 20670903 DOI: 10.1016/s1473-3099(10)70098-0] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
More than 100 years after the discovery of human American trypanosomiasis by Carlos Chagas, our knowledge and management of the disease are profoundly changing. Substantial progress made by disease control programmes in most endemic areas contrasts with persisting difficulties in the Gran Chaco region in South America and the recent emergence of the disease in non-endemic areas because of population movements. In terms of pathogenesis, major discoveries have been made about the life cycle and genomics of Trypanosoma cruzi, and the role of the parasite itself in the chronic phase of the disease. From a clinical perspective, a growing number of arguments have challenged the notion of an indeterminate phase, and suggest new approaches to manage patients. New methods such as standardised PCR will be necessary to ensure follow-up of this chronic infection. Although drugs for treatment of Chagas disease are limited, poorly tolerated, and not very effective, treatment indications are expanding. The results of the Benznidazole Evaluation For Interrupting Trypanosomiasis (BENEFIT) trial in 2012 will also help to inform treatment. Mobilisation of financial resources to fund research on diagnosis and randomised controlled trials of treatment are international health priorities.
Collapse
|
161
|
"Everything you always wanted to know about sex (but were afraid to ask)" in Leishmania after two decades of laboratory and field analyses. PLoS Pathog 2010; 6:e1001004. [PMID: 20808896 PMCID: PMC2924324 DOI: 10.1371/journal.ppat.1001004] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Leishmaniases remain a major public health problem today (350 million people at risk, 12 million infected, and 2 million new infections per year). Despite the considerable progress in cellular and molecular biology and in evolutionary genetics since 1990, the debate on the population structure and reproductive mode of Leishmania is far from being settled and therefore deserves further investigation. Two major hypotheses coexist: clonality versus sexuality. However, because of the lack of clear evidence (experimental or biological confirmation) of sexuality in Leishmania parasites, until today it has been suggested and even accepted that Leishmania species were mainly clonal with infrequent genetic recombination (see [1] for review). Two recent publications, one on Leishmania major (an in vitro experimental study) and one on Leishmania braziliensis (a population genetics analysis), once again have challenged the hypothesis of clonal reproduction. Indeed, the first study experimentally evidenced genetic recombination and proposed that Leishmania parasites are capable of having a sexual cycle consistent with meiotic processes inside the insect vector. The second investigation, based on population genetics studies, showed strong homozygosities, an observation that is incompatible with a predominantly clonal mode of reproduction at an ecological time scale (∼20–500 generations). These studies highlight the need to advance the knowledge of Leishmania biology. In this paper, we first review the reasons stimulating the continued debate and then detail the next essential steps to be taken to clarify the Leishmania reproduction model. Finally, we widen the discussion to other Trypanosomatidae and show that the progress in Leishmania biology can improve our knowledge of the evolutionary genetics of American and African trypanosomes.
Collapse
|
162
|
Bhattacharyya T, Brooks J, Yeo M, Carrasco HJ, Lewis MD, Llewellyn MS, Miles MA. Analysis of molecular diversity of the Trypanosoma cruzi trypomastigote small surface antigen reveals novel epitopes, evidence of positive selection and potential implications for lineage-specific serology. Int J Parasitol 2010; 40:921-8. [DOI: 10.1016/j.ijpara.2010.01.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 01/08/2010] [Accepted: 01/10/2010] [Indexed: 10/19/2022]
|
163
|
Alternative lifestyles: the population structure of Trypanosoma cruzi. Acta Trop 2010; 115:35-43. [PMID: 19695212 DOI: 10.1016/j.actatropica.2009.08.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 07/22/2009] [Accepted: 08/13/2009] [Indexed: 11/23/2022]
Abstract
The genetic palette from which the spectrum of variability in Trypanosoma cruzi has been drawn is astonishingly limited. In this review we address the roots of this unusual pedigree and the usefulness of various taxonomic markers in relation to the manifestation of clinical disease and the geographic distribution of the parasite. The circumstances leading to the population structure of the extant strains were dictated by the unusual and apparently exceedingly rare mode of genetic exchange employed in this species, that being the non-meiotic fusion of two diploid cells. Two-hybridization events have been postulated in the whole of the T. cruzi pedigree, the first of which yielded the four predominant nuclear genotypes. Hybridization may be a common occurrence among closely related strains of T. cruzi, but either infrequent or inefficient when two diverse strains attempt the process. Two of the genotypes define the parental lineages, while the other two are mosaics of the parental contributions distinguished from one another by polymorphisms accumulated after the separation of a common, homozygous hybrid progeny line. The greatest genetic complexity is seen in the result of the second fusion event between one of the original parental strains and a progeny strain. The second generation of progeny reveals the proximal consequences of fusion, maintaining widespread nuclear heterozygosity and the first examples of recombination between the genotypes involved in the second hybridization. If the genesis of the heterozygous progeny follows the same path as their predecessors, these lines will move toward homozygosity after having had the opportunity for recombination. Thus, the total number of alleles may increase to five in another few million years.
Collapse
|
164
|
Abad-Franch F, Santos WS, Schofield CJ. Research needs for Chagas disease prevention. Acta Trop 2010; 115:44-54. [PMID: 20227378 DOI: 10.1016/j.actatropica.2010.03.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 02/17/2010] [Accepted: 03/05/2010] [Indexed: 11/30/2022]
Abstract
We present an overview of the two main strategies for the primary (vector control) and secondary (patient care) prevention of Chagas disease (CD). We identify major advances, knowledge gaps, and key research needs in both areas. Improved specific chemotherapy, including more practical formulations (e.g., paediatric) or combinations of existing drugs, and a better understanding of pathogenesis, including the relative weights of parasite and host genetic makeup, are clearly needed. Regarding CD vectors, we find that only about 10-20% of published papers on triatomines deal directly with disease control. We pinpoint the pitfalls of the current consensus on triatomine systematics, particularly within the Triatomini, and suggest how some straightforward sampling and analytical strategies would improve research on vector ecology, naturally leading to sounder control-surveillance schemes. We conclude that sustained research on CD prevention is still crucial. In the past, it provided not only the know-how, but also the critical mass of scientists needed to foster and consolidate CD prevention programmes; in the future, both patient care and long-term vector control would nonetheless benefit from more sharply focused, problem-oriented research.
Collapse
Affiliation(s)
- Fernando Abad-Franch
- Instituto Leônidas e Maria Deane-Fiocruz Amazonia, Rua Teresina 476, 69057-070 Manaus, Amazonas, Brazil.
| | | | | |
Collapse
|
165
|
Detwiler JT, Criscione CD. An infectious topic in reticulate evolution: introgression and hybridization in animal parasites. Genes (Basel) 2010; 1:102-23. [PMID: 24710013 PMCID: PMC3960858 DOI: 10.3390/genes1010102] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 06/07/2010] [Accepted: 06/07/2010] [Indexed: 02/08/2023] Open
Abstract
Little attention has been given to the role that introgression and hybridization have played in the evolution of parasites. Most studies are host-centric and ask if the hybrid of a free-living species is more or less susceptible to parasite infection. Here we focus on what is known about how introgression and hybridization have influenced the evolution of protozoan and helminth parasites of animals. There are reports of genome or gene introgression from distantly related taxa into apicomplexans and filarial nematodes. Most common are genetic based reports of potential hybridization among congeneric taxa, but in several cases, more work is needed to definitively conclude current hybridization. In the medically important Trypanosoma it is clear that some clonal lineages are the product of past hybridization events. Similarly, strong evidence exists for current hybridization in human helminths such as Schistosoma and Ascaris. There remain topics that warrant further examination such as the potential hybrid origin of polyploid platyhelminths. Furthermore, little work has investigated the phenotype or fitness, and even less the epidemiological significance of hybrid parasites.
Collapse
Affiliation(s)
- Jillian T Detwiler
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843, USA.
| | - Charles D Criscione
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843, USA.
| |
Collapse
|
166
|
Lewis MD, Ma J, Yeo M, Carrasco HJ, Llewellyn MS, Miles MA. Genotyping of Trypanosoma cruzi: systematic selection of assays allowing rapid and accurate discrimination of all known lineages. Am J Trop Med Hyg 2010; 81:1041-9. [PMID: 19996435 DOI: 10.4269/ajtmh.2009.09-0305] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Trypanosoma cruzi, the agent of Chagas disease, can be subdivided into six discrete typing units (DTUs), TcI, TcIIa, TcIIb, TcIIc, TcIId or TcIIe, each having distinct epidemiologically important features. Dozens of genetic markers are available to determine the DTU to which a T. cruzi isolate belongs, but there is no consensus on which should be used. We selected five assays: three polymerase chain reaction (PCR)-restriction fragment length polymorphisms based on single nucleotide polymorphisms (SNPs) in the HSP60, Histone H1, and GPI loci, and PCR product size polymorphism of the LSU rDNA and mini-exon loci. Each assay was tested for its capacity to differentiate between DTUs using a panel of 48 genetically diverse T. cruzi clones. Some markers allowed unequivocal identification of individual DTUs, however, only by using a combination of multiple markers could all six DTUs be resolved. Based upon the results we recommend a triple-assay comprising the LSU rDNA, HSP60 and GPI markers for reliable, rapid, low-cost DTU assignment.
Collapse
Affiliation(s)
- Michael D Lewis
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
| | | | | | | | | | | |
Collapse
|
167
|
Modelling the Transmission of Trypanosoma cruzi: The Need for an Integrated Genetic Epidemiological and Population Genomics Approach. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 673:200-11. [DOI: 10.1007/978-1-4419-6064-1_14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
|
168
|
Zingales B, Andrade SG, Briones MRS, Campbell DA, Chiari E, Fernandes O, Guhl F, Lages-Silva E, Macedo AM, Machado CR, Miles MA, Romanha AJ, Sturm NR, Tibayrenc M, Schijman AG. A new consensus for Trypanosoma cruzi intraspecific nomenclature: second revision meeting recommends TcI to TcVI. Mem Inst Oswaldo Cruz 2009; 104:1051-4. [PMID: 20027478 DOI: 10.1590/s0074-02762009000700021] [Citation(s) in RCA: 719] [Impact Index Per Article: 47.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Accepted: 10/07/2009] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | | | | | | | - F Guhl
- Universidad de los Andes, Colombia
| | | | - AM Macedo
- Universidade Federal de Minas Gerais, Brasil
| | - CR Machado
- Universidade Federal de Minas Gerais, Brasil
| | - MA Miles
- London School of Hygiene and Tropical Medicine, UK
| | - AJ Romanha
- London School of Hygiene and Tropical Medicine, UK
| | | | | | - AG Schijman
- Instituto de Ingeniería Genética y Biología Molecular, Argentina
| |
Collapse
|
169
|
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.
Collapse
|
170
|
Trypanosoma cruzi IIc: phylogenetic and phylogeographic insights from sequence and microsatellite analysis and potential impact on emergent Chagas disease. PLoS Negl Trop Dis 2009; 3:e510. [PMID: 19721699 PMCID: PMC2727949 DOI: 10.1371/journal.pntd.0000510] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 07/30/2009] [Indexed: 11/19/2022] Open
Abstract
Trypanosoma cruzi, the etiological agent of Chagas disease, is highly genetically diverse. Numerous lines of evidence point to the existence of six stable genetic lineages or DTUs: TcI, TcIIa, TcIIb, TcIIc, TcIId, and TcIIe. Molecular dating suggests that T. cruzi is likely to have been an endemic infection of neotropical mammalian fauna for many millions of years. Here we have applied a panel of 49 polymorphic microsatellite markers developed from the online T. cruzi genome to document genetic diversity among 53 isolates belonging to TcIIc, a lineage so far recorded almost exclusively in silvatic transmission cycles but increasingly a potential source of human infection. These data are complemented by parallel analysis of sequence variation in a fragment of the glucose-6-phosphate isomerase gene. New isolates confirm that TcIIc is associated with terrestrial transmission cycles and armadillo reservoir hosts, and demonstrate that TcIIc is far more widespread than previously thought, with a distribution at least from Western Venezuela to the Argentine Chaco. We show that TcIIc is truly a discrete T. cruzi lineage, that it could have an ancient origin and that diversity occurs within the terrestrial niche independently of the host species. We also show that spatial structure among TcIIc isolates from its principal host, the armadillo Dasypus novemcinctus, is greater than that among TcI from Didelphis spp. opossums and link this observation to differences in ecology of their respective niches. Homozygosity in TcIIc populations and some linkage indices indicate the possibility of recombination but cannot yet be effectively discriminated from a high genome-wide frequency of gene conversion. Finally, we suggest that the derived TcIIc population genetic data have a vital role in determining the origin of the epidemiologically important hybrid lineages TcIId and TcIIe.
Collapse
|
171
|
Teixeira ARL, Gomes C, Lozzi SP, Hecht MM, Rosa ADC, Monteiro PS, Bussacos AC, Nitz N, McManus C. Environment, interactions between Trypanosoma cruzi and its host, and health. CAD SAUDE PUBLICA 2009; 25 Suppl 1:S32-44. [PMID: 19287864 DOI: 10.1590/s0102-311x2009001300004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 04/09/2008] [Indexed: 12/14/2022] Open
Abstract
An epidemiological chain involving Trypanosoma cruzi is discussed at the environmental level, and in terms of fine molecular interactions in invertebrate and vertebrate hosts dwelling in different ecosystems. This protozoan has a complex, genetically controlled plasticity, which confers adaptation to approximately 40 blood-sucking triatomine species and to over 1,000 mammalian species, fulfilling diverse metabolic requirements in its complex life-cycle. The Tr. cruzi infections are deeply embedded in countless ecotypes, where they are difficult to defeat using the control methods that are currently available. Many more field and laboratory studies are required to obtain data and information that may be used for the control and prevention of Tr. cruzi infections and their various disease manifestations. Emphasis should be placed on those sensitive interactions at cellular and environmental levels that could become selected targets for disease prevention. In the short term, new technologies for social mobilization should be used by people and organizations working for justice and equality through health information and promotion. A mass media directed program could deliver education, information and communication to protect the inhabitants at risk of contracting Tr. cruzi infections.
Collapse
|
172
|
The molecular epidemiology and phylogeography of Trypanosoma cruzi and parallel research on Leishmania: looking back and to the future. Parasitology 2009; 136:1509-28. [DOI: 10.1017/s0031182009990977] [Citation(s) in RCA: 184] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYTrypanosoma cruzi is the protozoan agent of Chagas disease, and the most important parasitic disease in Latin America. Protozoa of the genus Leishmania are global agents of visceral and cutaneous leishmaniasis, fatal and disfiguring diseases. In the 1970s multilocus enzyme electrophoresis demonstrated that T. cruzi is a heterogeneous complex. Six zymodemes were described, corresponding with currently recognized lineages, TcI and TcIIa-e – now defined by multiple genetic markers. Molecular epidemiology has substantially resolved the phylogeography and ecological niches of the T. cruzi lineages. Genetic hybridization has fundamentally influenced T. cruzi evolution and epidemiology of Chagas disease. Genetic exchange of T. cruzi in vitro involves fusion of diploids and genome erosion, producing aneuploid hybrids. Transgenic fluorescent clones are new tools to elucidate molecular genetics and phenotypic variation. We speculate that pericardial sequestration plays a role in pathogenesis. Multilocus sequence typing, microsatellites and, ultimately, comparative genomics are improving understanding of T. cruzi population genetics. Similarly, in Leishmania, genetic groups have been defined, including epidemiologically important hybrids; genetic exchange can occur in the sand fly vector. We describe the profound impact of this parallel research on genetic diversity of T. cruzi and Leishmania, in the context of epidemiology, taxonomy and disease control.
Collapse
|
173
|
Subileau M, Barnabé C, Douzery E, Diosque P, Tibayrenc M. Trypanosoma cruzi: New insights on ecophylogeny and hybridization by multigene sequencing of three nuclear and one maxicircle genes. Exp Parasitol 2009; 122:328-37. [DOI: 10.1016/j.exppara.2009.04.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2009] [Revised: 04/07/2009] [Accepted: 04/12/2009] [Indexed: 11/28/2022]
|
174
|
Alves MJM, Mortara RA. A century of research: what have we learned about the interaction of Trypanosoma cruzi with host cells? Mem Inst Oswaldo Cruz 2009; 104 Suppl 1:76-88. [DOI: 10.1590/s0074-02762009000900013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Accepted: 05/29/2009] [Indexed: 12/31/2022] Open
|
175
|
Pena SDJ, Machado CR, Macedo AM. Trypanosoma cruzi: ancestral genomes and population structure. Mem Inst Oswaldo Cruz 2009; 104 Suppl 1:108-14. [PMID: 19753465 DOI: 10.1590/s0074-02762009000900016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 06/01/2009] [Indexed: 11/22/2022] Open
|
176
|
Duffy CW, Morrison LJ, Black A, Pinchbeck GL, Christley RM, Schoenefeld A, Tait A, Turner CMR, MacLeod A. Trypanosoma vivax displays a clonal population structure. Int J Parasitol 2009; 39:1475-83. [PMID: 19520081 DOI: 10.1016/j.ijpara.2009.05.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2009] [Revised: 05/21/2009] [Accepted: 05/22/2009] [Indexed: 10/20/2022]
Abstract
African animal trypanosomiasis, or Nagana, is a debilitating and economically costly disease with a major impact on animal health in sub-Saharan Africa. Trypanosoma vivax, one of the principal trypanosome species responsible for the disease, infects a wide host range including cattle, goats, horses and donkeys and is transmitted both cyclically by tsetse flies and mechanically by other biting flies, resulting in a distribution covering large swathes of South America and much of sub-Saharan Africa. While there is evidence for mating in some of the related trypanosome species, Trypanosoma brucei, Trypanosoma congolense and Trypanosoma cruzi, very little work has been carried out to examine this question in T. vivax. Understanding whether mating occurs in T. vivax will provide insight into the dynamics of trait inheritance, for example the spread of drug resistance, as well as examining the origins of meiosis in the order Kinetoplastida. With this in mind we have identified orthologues of eight core meiotic genes within the genome, the presence of which imply that the potential for mating exists in this species. In order to address whether mating occurs, we have investigated a sympatric field population of T. vivax collected from livestock in The Gambia, using microsatellite markers developed for this species. Our analysis has identified a clonal population structure showing significant linkage disequilibrium, homozygote deficits and disagreement with Hardy-Weinberg predictions at six microsatellite loci, indicative of a lack of mating in this population of T. vivax.
Collapse
Affiliation(s)
- Craig W Duffy
- Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, Faculty of Veterinary Medicine, University of Glasgow, Glasgow G12 8TA, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
177
|
Flegontov PN, Zhirenkina EN, Gerasimov ES, Ponirovsky EN, Strelkova MV, Kolesnikov AA. Selective amplification of maxicircle classes during the life cycle of Leishmania major. Mol Biochem Parasitol 2009; 165:142-52. [DOI: 10.1016/j.molbiopara.2009.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2008] [Revised: 01/23/2009] [Accepted: 01/26/2009] [Indexed: 10/21/2022]
|
178
|
Discovery of mating in the major African livestock pathogen Trypanosoma congolense. PLoS One 2009; 4:e5564. [PMID: 19440370 PMCID: PMC2679202 DOI: 10.1371/journal.pone.0005564] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 04/12/2009] [Indexed: 12/04/2022] Open
Abstract
The protozoan parasite, Trypanosoma congolense, is one of the most economically important pathogens of livestock in Africa and, through its impact on cattle health and productivity, has a significant effect on human health and well being. Despite the importance of this parasite our knowledge of some of the fundamental biological processes is limited. For example, it is unknown whether mating takes place. In this paper we have taken a population genetics based approach to address this question. The availability of genome sequence of the parasite allowed us to identify polymorphic microsatellite markers, which were used to genotype T. congolense isolates from livestock in a discrete geographical area of The Gambia. The data showed a high level of diversity with a large number of distinct genotypes, but a deficit in heterozygotes. Further analysis identified cryptic genetic subdivision into four sub-populations. In one of these, parasite genotypic diversity could only be explained by the occurrence of frequent mating in T. congolense. These data are completely inconsistent with previous suggestions that the parasite expands asexually in the absence of mating. The discovery of mating in this species of trypanosome has significant consequences for the spread of critical traits, such as drug resistance, as well as for fundamental aspects of the biology and epidemiology of this neglected but economically important pathogen.
Collapse
|
179
|
Llewellyn MS, Miles MA, Carrasco HJ, Lewis MD, Yeo M, Vargas J, Torrico F, Diosque P, Valente V, Valente SA, Gaunt MW. Genome-scale multilocus microsatellite typing of Trypanosoma cruzi discrete typing unit I reveals phylogeographic structure and specific genotypes linked to human infection. PLoS Pathog 2009; 5:e1000410. [PMID: 19412340 PMCID: PMC2669174 DOI: 10.1371/journal.ppat.1000410] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 04/01/2009] [Indexed: 11/28/2022] Open
Abstract
Trypanosoma cruzi is the most important parasitic infection in Latin America and is also genetically highly diverse, with at least six discrete typing units (DTUs) reported: Tc I, IIa, IIb, IIc, IId, and IIe. However, the current six-genotype classification is likely to be a poor reflection of the total genetic diversity present in this undeniably ancient parasite. To determine whether epidemiologically important information is "hidden" at the sub-DTU level, we developed a 48-marker panel of polymorphic microsatellite loci to investigate population structure among 135 samples from across the geographic distribution of TcI. This DTU is the major cause of resurgent human disease in northern South America but also occurs in silvatic triatomine vectors and mammalian reservoir hosts throughout the continent. Based on a total dataset of 12,329 alleles, we demonstrate that silvatic TcI populations are extraordinarily genetically diverse, show spatial structuring on a continental scale, and have undergone recent biogeographic expansion into the southern United States of America. Conversely, the majority of human strains sampled are restricted to two distinct groups characterised by a considerable reduction in genetic diversity with respect to isolates from silvatic sources. In Venezuela, most human isolates showed little identity with known local silvatic strains, despite frequent invasion of the domestic setting by infected adult vectors. Multilocus linkage indices indicate predominantly clonal parasite propagation among all populations. However, excess homozygosity among silvatic strains and raised heterozygosity among domestic populations suggest that some level of genetic recombination cannot be ruled out. The epidemiological significance of these findings is discussed.
Collapse
|
180
|
Affiliation(s)
- Michael A Miles
- Pathogen Molecular Biology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
| | | | | |
Collapse
|
181
|
Akopyants NS, Kimblin N, Secundino N, Patrick R, Peters N, Lawyer P, Dobson DE, Beverley SM, Sacks DL. Demonstration of genetic exchange during cyclical development of Leishmania in the sand fly vector. Science 2009; 324:265-8. [PMID: 19359589 PMCID: PMC2729066 DOI: 10.1126/science.1169464] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Genetic exchange has not been shown to be a mechanism underlying the extensive diversity of Leishmania parasites. We report here evidence that the invertebrate stages of Leishmania are capable of having a sexual cycle consistent with a meiotic process like that described for African trypanosomes. Hybrid progeny were generated that bore full genomic complements from both parents, but kinetoplast DNA maxicircles from one parent. Mating occurred only in the sand fly vector, and hybrids were transmitted to the mammalian host by sand fly bite. Genetic exchange likely contributes to phenotypic diversity in natural populations, and analysis of hybrid progeny will be useful for positional cloning of the genes controlling traits such as virulence, tissue tropism, and drug resistance.
Collapse
Affiliation(s)
- Natalia S. Akopyants
- Dept. of Molecular Microbiology, Washington University School of Medicine, St. Louis MO 63110 USA
| | - Nicola Kimblin
- Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda MD, 20892
| | - Nagila Secundino
- Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda MD, 20892
| | - Rachel Patrick
- Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda MD, 20892
| | - Nathan Peters
- Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda MD, 20892
| | - Phillip Lawyer
- Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda MD, 20892
| | - Deborah E. Dobson
- Dept. of Molecular Microbiology, Washington University School of Medicine, St. Louis MO 63110 USA
| | - Stephen M. Beverley
- Dept. of Molecular Microbiology, Washington University School of Medicine, St. Louis MO 63110 USA
| | - David L. Sacks
- Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda MD, 20892
| |
Collapse
|
182
|
Falla A, Herrera C, Fajardo A, Montilla M, Vallejo GA, Guhl F. Haplotype identification within Trypanosoma cruzi I in Colombian isolates from several reservoirs, vectors and humans. Acta Trop 2009; 110:15-21. [PMID: 19135020 DOI: 10.1016/j.actatropica.2008.12.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 11/07/2008] [Accepted: 12/12/2008] [Indexed: 10/21/2022]
Abstract
Genetic variability in the Trypanosoma cruzi I group has recently been revealed in Colombian isolates from humans, reservoirs and vectors. Genomic rearrangements and the polymorphic regions in taxonomic markers, such as the miniexon gene, have led to the development of molecular tools to identify phylogenetic haplotypes in T. cruzi isolates. From genetic polymorphisms found in T. cruzi I isolates, they have been classified into four haplotypes according to their epidemiologic transmission cycles. Haplotype Ia is associated with domestic isolates, from Rhodnius prolixus; haplotype Ib, with the domestic and peridomestic cycle, mainly associated with Triatoma dimidiata; haplotype Ic is a poorly characterized group, which has been associated with the peridomestic cycle; and haplotype Id has been related to the sylvatic cycle. In order to demonstrate that the circulating T. cruzi I isolates in Colombia can be classified in the four proposed haplotypes, specific primers were designed on polymorphic regions of the miniexon gene's intergenic sequences. This set of primers allowed the molecular characterization of 33 Colombian isolates, classifying them into three of the four proposed haplotypes (Ia, Ib and Id). Results obtained from maximum parsimony and maximum-likelihood-based phylogenetic analyses correlated with the molecular classification of the isolates and their transmission cycles. This study brings insights into the Chagas disease epidemiology and the parasite's transmission dynamics.
Collapse
|
183
|
Venegas J, Coñoepan W, Pichuantes S, Miranda S, Jercic MI, Gajardo M, Sánchez G. Phylogenetic analysis of microsatellite markers further supports the two hybridization events hypothesis as the origin of the Trypanosoma cruzi lineages. Parasitol Res 2009; 105:191-9. [DOI: 10.1007/s00436-009-1386-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Accepted: 02/26/2009] [Indexed: 11/28/2022]
|
184
|
Noireau F, Diosque P, Jansen AM. Trypanosoma cruzi: adaptation to its vectors and its hosts. Vet Res 2009; 40:26. [PMID: 19250627 PMCID: PMC2695024 DOI: 10.1051/vetres/2009009] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 02/26/2009] [Indexed: 12/19/2022] Open
Abstract
American trypanosomiasis is a parasitic zoonosis that occurs throughout Latin America. The etiological agent, Trypanosoma cruzi, is able to infect almost all tissues of its mammalian hosts and spreads in the environment in multifarious transmission cycles that may or not be connected. This biological plasticity, which is probably the result of the considerable heterogeneity of the taxon, exemplifies a successful adaptation of a parasite resulting in distinct outcomes of infection and a complex epidemiological pattern. In the 1990s, most endemic countries strengthened national control programs to interrupt the transmission of this parasite to humans. However, many obstacles remain to the effective control of the disease. Current knowledge of the different components involved in elaborate system that is American trypanosomiasis (the protozoan parasite T. cruzi, vectors Triatominae and the many reservoirs of infection), as well as the interactions existing within the system, is still incomplete. The Triatominae probably evolve from predatory reduvids in response to the availability of vertebrate food source. However, the basic mechanisms of adaptation of some of them to artificial ecotopes remain poorly understood. Nevertheless, these adaptations seem to be associated with a behavioral plasticity, a reduction in the genetic repertoire and increasing developmental instability.
Collapse
Affiliation(s)
- François Noireau
- UR 016, Institut de Recherche pour le Développement (IRD), Montpellier, France.
| | | | | |
Collapse
|
185
|
Venegas JA, Aslund L, Solari A. Cloning and characterization of a DNA polymerase beta gene from Trypanosoma cruzi. Parasitol Int 2009; 58:187-92. [PMID: 19567232 DOI: 10.1016/j.parint.2009.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2008] [Revised: 01/21/2009] [Accepted: 01/23/2009] [Indexed: 11/15/2022]
Abstract
A gene coding for a DNA polymerase beta from the Trypanosoma cruzi Miranda clone, belonging to the TcI lineage, was cloned (Miranda Tcpol beta), using the information from eight peptides of the T. cruzi beta-like DNA polymerase purified previously. The gene encodes for a protein of 403 amino acids which is very similar to the two T. cruzi CL Brener (TcIIe lineage) sequences published, but has three different residues in highly conserved segments. At the amino acid level, the identity of TcI-pol beta with mitochondrial pol beta and pol beta-PAK from other trypanosomatids was between 68-80% and 22-30%, respectively. Miranda Tc-pol beta protein has an N-terminal sequence similar to that described in the mitochondrial Crithidia fasciculata pol beta, which suggests that the TcI-pol beta plays a role in the organelle. Northern and Western analyses showed that this T. cruzi gene is highly expressed both in proliferative and non-proliferative developmental forms. These results suggest that, in addition to replication of kDNA in proliferative cells, this enzyme may have another function in non-proliferative cells, such as DNA repair role similar to that which has extensively been described in a vast spectrum of eukaryotic cells.
Collapse
Affiliation(s)
- Juan A Venegas
- Programa de Biología Celular y Molecular, ICBM, Universidad de Chile, Casilla 70086, Santiago-7, Chile.
| | | | | |
Collapse
|
186
|
Kawashita SY, da Silva CV, Mortara RA, Burleigh BA, Briones MRS. Homology, paralogy and function of DGF-1, a highly dispersed Trypanosoma cruzi specific gene family and its implications for information entropy of its encoded proteins. Mol Biochem Parasitol 2009; 165:19-31. [PMID: 19393159 DOI: 10.1016/j.molbiopara.2008.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 12/12/2008] [Accepted: 12/23/2008] [Indexed: 11/30/2022]
Abstract
Surface adhesion proteins are essential for Trypanosoma cruzi invasion of mammalian cells. Here we show that Dispersed Gene Family-1 (DGF-1) members, previously identified as nuclear repeated sequences present in several chromosomes and comprising the third largest T. cruzi specific gene family, have conserved adhesin motifs including four segments with significant similarity to human beta 7 integrin. Flow cytometry and biotinylation assays with anti-DGF-1 antibodies indicated that, as expected, DGF-1 members are expressed on the trypomastigote surface. The DGF-1 genealogy, inferred using T. cruzi Genome Project data and network phylogeny algorithms, suggests that this gene family is separated in at least three groups with differential distribution of functional domains. To identify which members of this gene family are expressed we used a combined approach of RT-PCR and codon usage profiles, showing that expressed members have a very biased codon usage favoring GC, whereas non-expressed members have a homogeneous distribution. Shannon information entropy was used to measure sequence variability and revealed four major high entropy segments in the extracellular domain of DGF-1 overlapping with important putative functional modules of the predicted proteins. Testing for natural selection, however, indicated that these high entropy segments were not under positive selection, which contradicts the notion that positive selection is the cause of high variability in specific domains of a protein relative to other less variable regions in the same molecule. We conjectured that members of the DGF-1 family might be associated with the ability of T. cruzi to bind extracellular matrix proteins, such as fibronectin and laminin, and speculated on mechanisms that would be generating the localized diversity in these molecules in the absence of selection.
Collapse
Affiliation(s)
- Silvia Y Kawashita
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | | | | | | | | |
Collapse
|
187
|
Abstract
In this introductory chapter, I stress one more time the urgency to better connect molecular epidemiology and evolutionary biology. I show how much population genetics and phylogenetic analyses can confer a considerable added value to all attempts to characterize strains and species of pathogens. The problems dealing with the mere definition of basic concepts, such as species, subspecies, or strains, are briefly summarized. Last, I show the important contribution of molecular epidemiology to our knowledge of the basic biology of pathogens and insist on the necessity not to separate the studies dealing with pathogens from those that concern the hosts and the vectors, in the case of vector-borne diseases.
Collapse
|
188
|
Sodré CL, Chapeaurouge AD, Kalume DE, de Mendonça Lima L, Perales J, Fernandes O. Proteomic map of Trypanosoma cruzi CL Brener: the reference strain of the genome project. Arch Microbiol 2008; 191:177-84. [PMID: 19002435 DOI: 10.1007/s00203-008-0439-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 09/08/2008] [Accepted: 10/13/2008] [Indexed: 12/11/2022]
Abstract
In this work two-dimensional gel electrophoresis combined with mass spectrometry was carried out in order to start the construction of a map of soluble proteins from epimastigote form of Trypanosoma cruzi CL Brener. This strain is a hybrid organism derived from two genotypes, T. cruzi I and T. cruzi II and was chosen for genome sequencing. The two-dimensional gel electrophoresis showed that most of proteins focused at 4-7 pH range. The identification demonstrated that several proteins were in multiple isoforms, such as tubulin and heat shock proteins. Potential targets for development of chemotherapeutic agents like arginine kinase, an enzyme absent from mammalian tissues that is involved in the energy supply of the parasite, were also detected.
Collapse
Affiliation(s)
- Cátia Lacerda Sodré
- Laboratory of Molecular Epidemiology of Infectious Diseases, Oswaldo Cruz Institute-IOC, Oswaldo Cruz Foundation-FIOCRUZ. Av. Brasil, 4365-Manguinhos, Rio de Janeiro, RJ 21045-900, Brazi.
| | | | | | | | | | | |
Collapse
|
189
|
León-Pérez F, Gómez-Garcia L, Alejandre-Aguilar R, López R, Monteón VM. Mexican Trypanosoma cruzi isolates: in vitro susceptibility of epimastigotes to anti-trypanosoma cruzi drugs and metacyclic forms to complement-mediated lysis. Vector Borne Zoonotic Dis 2008; 7:330-6. [PMID: 17760512 DOI: 10.1089/vbz.2006.0604] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Trypanosoma cruzi has a clonal organization with an ample array of genetic and phenotypic features and probably anaploid constitution. Consequently, the biological behavior, biochemistry, and molecular attributes may be distinctive for each parasite strain in different geographical regions. As far as we know, there is no published information on the susceptibility of Mexican T. cruzi stocks to anti-T. cruzi drugs such as benznidazole and gentian violet, or on its resistance to complement-mediated lysis. We studied 10 Mexican T. cruzi isolates from different geographical areas, such as the pacific coast (Oaxaca, Guerrero, and Nayarit States), central part of Mexico (Guanajuato State), Gulf of Mexico (Veracruz State), and the Yucatan Peninsula (Campeche State). We searched for the natural resistance to drugs in in vitro assay against the 10 Mexican isolates using epimastigote forms and the complement-mediated lysis using metacyclic trypomastigotes insect-derived in three of them (one for each geographic region). In general, we observed high resistance to benznidazole in all the Mexican isolates tested, but in the complement-mediated lysis test, they showed moderate to high susceptibility. Although it is necessary to expand this study by using trypomastigotes and the intracellular form to verify its biological role, we suggest that Mexican T. cruzi parasites may have a variable susceptibility to antibody-mediated lysis and high resistance to benznidazole.
Collapse
Affiliation(s)
- Floribeth León-Pérez
- Centro Investigación Enfermedades Tropicales, Universidad Autónoma de Campeche, Campeche, Mexico
| | | | | | | | | |
Collapse
|
190
|
Visualizing trypanosome sex. Trends Parasitol 2008; 24:425-8. [DOI: 10.1016/j.pt.2008.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 06/20/2008] [Accepted: 06/27/2008] [Indexed: 11/21/2022]
|
191
|
Pacheco RS, de Brito CMM, Sarquis O, Pires MQ, Borges-Pereira J, Lima MM. Genetic heterogeneity in Trypanosoma cruzi strains from naturally infected triatomine vectors in northeastern Brazil: epidemiological implications. Biochem Genet 2008; 43:519-30. [PMID: 16341768 DOI: 10.1007/s10528-005-8168-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Accepted: 12/07/2004] [Indexed: 10/25/2022]
Abstract
Eighteen Trypanosoma cruzi strains isolated from naturally infected triatomines were studied genetically. The majority of the strains were from Triatoma brasiliensis, the principal vector of Chagas disease in the northeast of Brazil. Multilocus enzyme electrophoresis (MLEE) and randomly amplified polymorphic DNA (RAPD) analyses were used to investigate the genotypic diversity and the spread of the T. cruzi genotypes in different environments. MLEE clearly distinguished two distinct isoenzyme profiles, and RAPD analysis revealed 10 different genotypes circulating in rural areas. The strains could be typed as isoenzyme variants of the T. cruzi principal zymodeme Z1 (T. cruzi I). An effective program of epidemiological vigilance is required to prevent the spread of T. cruzi I strains into human dwellings.
Collapse
Affiliation(s)
- Raquel S Pacheco
- Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Av. Brasil, 4365, Rio de Janeiro, Brazil.
| | | | | | | | | | | |
Collapse
|
192
|
Abstract
SUMMARYTrypanosoma cruzi, the agent of Chagas disease is associated with a very high clinical and epidemiological pleomorphism. This might be better understood through studies on the evolutionary history of the parasite. We explored here the value of antigen genes for the understanding of the evolution withinT. cruzi. We selected 11 genes and 12 loci associated with different functions and considered to be involved in host-parasite interaction (cell adhesion, infection, molecular mimicry). The polymorphism of the respective genes in a sample representative of the diversity ofT. cruziwas screened by PCR-RFLP and evolutionary relationships were inferred by phenetic analysis. Our results support the classification ofT. cruziin 2 major lineages and 6 discrete typing units (DTUs). The topology of the PCR-RFLP tree was the one that better fitted with the epidemiological features of the different DTUs: (i) lineage I, being encountered in sylvatic as well as domestic transmission cycles, (ii) IIa/c being associated with a sylvatic transmission cycle and (iii) IIb/d/e being associated with a domestic transmission cycle. Our study also supported the hypothesis that the evolutionary history ofT. cruzihas been shaped by a series of hybridization events in the framework of a predominant clonal evolution pattern.
Collapse
|
193
|
Usefulness of the polymerase chain reaction for monitoring cure of mice infected with different Trypanosoma cruzi clonal genotypes following treatment with benznidazole. Exp Parasitol 2008; 120:45-9. [PMID: 18533149 DOI: 10.1016/j.exppara.2008.04.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 03/03/2008] [Accepted: 04/25/2008] [Indexed: 11/22/2022]
Abstract
The capacity of the polymerase chain reaction (PCR) to detect the DNA of Trypanosoma cruzi was evaluated in 90 blood samples from BALB/c mice infected with T. cruzi cloned stocks of genotypes 19 and 20 (T. cruzi I) and 39 and 32 (T. cruzi II), and treated with benznidazole. The results from the fresh blood examination, hemoculture, and ELISA allowed to group the treated animals into: cured (TC), dissociated (DIS) and non-cured (NC). The PCR detected T. cruzi DNA in 50.9%, 58.3% and 100.0% of the samples from TC, DIS and NC mice, respectively. These DNA possibly derives from live T. cruzi or from recently lysed parasites, suggests that these animals are in fact not cured. The difference between the PCR results and results obtained using other techniques was statistically significant and independent of the parasite genotype. The PCR described has therefore potential to be used in cure control of treated patients.
Collapse
|
194
|
Pires SF, DaRocha WD, Freitas JM, Oliveira LA, Kitten GT, Machado CR, Pena SDJ, Chiari E, Macedo AM, Teixeira SMR. Cell culture and animal infection with distinct Trypanosoma cruzi strains expressing red and green fluorescent proteins. Int J Parasitol 2008; 38:289-97. [PMID: 17967460 DOI: 10.1016/j.ijpara.2007.08.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 08/07/2007] [Accepted: 08/14/2007] [Indexed: 10/22/2022]
Abstract
Different strains of Trypanosoma cruzi were transfected with an expression vector that allows the integration of green fluorescent protein (GFP) and red fluorescent protein (RFP) genes into the beta-tubulin locus by homologous recombination. The sites of integration of the GFP and RFP markers were determined by pulse-field gel electrophoresis and Southern blot analyses. Cloned cell lines selected from transfected epimastigote populations maintained high levels of fluorescent protein expression even after 6 months of in vitro culture of epimastigotes in the absence of drug selection. Fluorescent trypomastigotes and amastigotes were observed within Vero cells in culture as well as in hearts and diaphragms of infected mice. The infectivity of the GFP- and RFP-expressing parasites in tissue culture cells was comparable to wild type populations. Furthermore, GFP- and RFP-expressing parasites were able to produce similar levels of parasitemia in mice compared with wild type parasites. Cell cultures infected simultaneously with two cloned cell lines from the same parasite strain, each one expressing a distinct fluorescent marker, showed that at least two different parasites are able to infect the same cell. Double-infected cells were also detected when GFP- and RFP-expressing parasites were derived from strains belonging to two distinct T. cruzi lineages. These results show the usefulness of parasites expressing GFP and RFP for the study of various aspects of T. cruzi infection including the mechanisms of cell invasion, genetic exchange among parasites and the differential tissue distribution in animal models of Chagas disease.
Collapse
Affiliation(s)
- S F Pires
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|
195
|
Valadares HMS, Pimenta JR, de Freitas JM, Duffy T, Bartholomeu DC, Oliveira RDP, Chiari E, Moreira MDCV, Filho GB, Schijman AG, Franco GR, Machado CR, Pena SDJ, Macedo AM. Genetic profiling of Trypanosoma cruzi directly in infected tissues using nested PCR of polymorphic microsatellites. Int J Parasitol 2007; 38:839-50. [PMID: 18154957 DOI: 10.1016/j.ijpara.2007.10.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 10/15/2007] [Accepted: 10/25/2007] [Indexed: 11/18/2022]
Abstract
The investigation of the importance of the genetics of Trypanosoma cruzi in determining the clinical course of Chagas disease will depend on precise characterisation of the parasites present in the tissue lesions. This can be adequately accomplished by the use of hypervariable nuclear markers such as microsatellites. However the unilocal nature of these loci and the scarcity of parasites in chronic lesions make it necessary to use high sensitivity PCR with nested primers, whose design depends on the availability of long flanking regions, a feature not hitherto available for any known T. cruzi microsatellites. Herein, making use of the extensive T. cruzi genome sequence now available and using the Tandem Repeats Finder software, it was possible to identify and characterise seven new microsatellite loci--six composed of trinucleotide (TcTAC15, TcTAT20, TcAAT8, TcATT14, TcGAG10 and TcCAA10) and one composed of tetranucleotide (TcAAAT6) motifs. All except the TcCAA10 locus were physically mapped onto distinct intergenic regions of chromosome III of the CL Brener clone contigs. The TcCAA10 locus was localised within a hypothetical protein gene in the T. cruzi genome. All microsatellites were polymorphic and useful for T. cruzi genetic variability studies. Using the TcTAC15 locus it was possible to separate the strains belonging to the T. cruzi I lineage (DTU I) from those belonging to T. cruzi II (DTU IIb), T. cruzi III (DTU IIc) and a hybrid group (DTU IId, IIe). The long flanking regions of these novel microsatellites allowed construction of nested primers and the use of full nested PCR protocols. This strategy enabled us to detect and differentiate T. cruzi strains directly in clinical specimens including heart, blood, CSF and skin tissues from patients in the acute and chronic phases of Chagas disease.
Collapse
Affiliation(s)
- Helder Magno Silva Valadares
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, MG, Brazil
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
196
|
Toma HK, Yamada-Ogatta SF, Brandão A, Krieger MA, Goldenberg S, Fernandes O. Trypanosoma cruzi: Subtractive hybridization as a molecular strategy to generate new targets to distinguish groups and hybrids. Exp Parasitol 2007; 117:178-87. [PMID: 17597613 DOI: 10.1016/j.exppara.2007.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 03/30/2007] [Accepted: 04/23/2007] [Indexed: 11/19/2022]
Abstract
RAPD analysis and sequences of the mini-exon and ribosomal genes show that Trypanosoma cruzi can be clustered into two phylogenetic groups-T. cruzi I and II. Herein, the Representational Difference Analysis (RDA) method was used, providing new targets specific for each group. After three rounds of RDA hybridizing F strain (tester) with Y strain (driver) and vice-versa, an F-specific (F#30) and Y-specific (Y#22) clone were obtained specifically recognizing isolates from Amazonas (T. cruzi I) and Piauí (T. cruzi II). These segments corresponded to an unspecified protein (F#30) and a trans-sialidase (Y#22). Analysis of the F#30 sequence in T. cruzi I, T. cruzi II and zymodeme 3 samples displayed negligible specific differences that distinguished each group. In addition this F#30 gene has great potential as a hybrid marker.
Collapse
Affiliation(s)
- Helena K Toma
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Av. Brigadeiro Trompowsky s/n, 21941-590 Rio de Janeiro, RJ, Brazil
| | | | | | | | | | | |
Collapse
|
197
|
Iwagami M, Higo H, Miura S, Yanagi T, Tada I, Kano S, Agatsuma T. Molecular phylogeny of Trypanosoma cruzi from Central America (Guatemala) and a comparison with South American strains. Parasitol Res 2007; 102:129-34. [PMID: 17828552 DOI: 10.1007/s00436-007-0739-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 08/21/2007] [Indexed: 11/30/2022]
Abstract
Molecular phylogenetic analysis was carried out for 21 strains of Trypanosoma cruzi, nine of which were obtained from Guatemala and 12 from South America. Phylogenetic trees were constructed using the nucleotide sequences of two nuclear gene regions, dihydrofolate reductase-thymidylate synthase (DHFR-TS) and trypanothione reductase (TR), and contiguous portions of two mitochondrial genes, cytochrome oxidase subunit II (COII) and reduced nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1). Possible genetic exchange between the rather divergent lineages of T. cruzi II from South America was suggested in the trees of the two nuclear genes. T. cruzi I strains obtained from Guatemala and Colombia were identical in all the genes examined, but other T. cruzi I isolates from South America were rather polymorphic in the DHFR-TS and mitochondrial genes. No genetic exchange was identified between T. cruzi I populations from Central and South America in the present study.
Collapse
Affiliation(s)
- M Iwagami
- Department of Environmental Health Science, Kochi University School of Medicine, Oko, Nankoku, Kochi, 783-8505, Japan
| | | | | | | | | | | | | |
Collapse
|
198
|
Análisis de polimorfismos en los genes tripanotión reductasa y cruzipaína en cepas colombianas de Trypanosoma cruzi. BIOMEDICA 2007. [DOI: 10.7705/biomedica.v27i1.248] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
199
|
O'Connor O, Bosseno MF, Barnabé C, Douzery EJP, Brenière SF. Genetic clustering of Trypanosoma cruzi I lineage evidenced by intergenic miniexon gene sequencing. INFECTION GENETICS AND EVOLUTION 2007; 7:587-93. [PMID: 17553755 DOI: 10.1016/j.meegid.2007.05.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 04/27/2007] [Accepted: 05/01/2007] [Indexed: 11/19/2022]
Abstract
American trypanosomiasis or Chagas disease is endemic in Latin America and caused by the flagellate Trypanosoma cruzi, which exhibits broad genetic variation. In various areas, the transmission of Chagas disease is ensured by sylvatic vectors, mainly carrying the evolutionary lineage I of T. cruzi. Despite its epidemiological importance, this lineage is poorly studied. Here, we investigated the genetic variability and the phylogenetic relationships within T. cruzi I using sequences of the non-transcribed spacer of miniexon genes. The variability was firstly analysed between 10 repeats of spacer-miniexon genes in two strains of T. cruzi I and in the CL Brener strain, showing lower intra-strain variability than inter-strain. Furthermore, the phylogenetic analysis of 19 T. cruzi I strains (49 copies in total) clusters the copies into at least three groups. Two evolutionary phenomena can be proposed to explain the partition of the strains: (i) an association between strains and Didelphis sp. hosts and (ii) geographical clustering between the North American and South American strains. Thereby, the miniexon gene is an attractive marker to establish the phylogeny of lineage I and explore relationships between T. cruzi and mammal hosts.
Collapse
Affiliation(s)
- Olivia O'Connor
- Institut de Recherche pour le Développement (IRD), Département Sociétés et Santé, UR 008 et 165, Montpellier, France
| | | | | | | | | |
Collapse
|
200
|
An expanded inventory of conserved meiotic genes provides evidence for sex in Trichomonas vaginalis. PLoS One 2007; 3:e2879. [PMID: 18663385 PMCID: PMC2488364 DOI: 10.1371/journal.pone.0002879] [Citation(s) in RCA: 192] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 06/08/2008] [Indexed: 12/23/2022] Open
Abstract
Meiosis is a defining feature of eukaryotes but its phylogenetic distribution has not been broadly determined, especially among eukaryotic microorganisms (i.e. protists)-which represent the majority of eukaryotic 'supergroups'. We surveyed genomes of animals, fungi, plants and protists for meiotic genes, focusing on the evolutionarily divergent parasitic protist Trichomonas vaginalis. We identified homologs of 29 components of the meiotic recombination machinery, as well as the synaptonemal and meiotic sister chromatid cohesion complexes. T. vaginalis has orthologs of 27 of 29 meiotic genes, including eight of nine genes that encode meiosis-specific proteins in model organisms. Although meiosis has not been observed in T. vaginalis, our findings suggest it is either currently sexual or a recent asexual, consistent with observed, albeit unusual, sexual cycles in their distant parabasalid relatives, the hypermastigotes. T. vaginalis may use meiotic gene homologs to mediate homologous recombination and genetic exchange. Overall, this expanded inventory of meiotic genes forms a useful "meiosis detection toolkit". Our analyses indicate that these meiotic genes arose, or were already present, early in eukaryotic evolution; thus, the eukaryotic cenancestor contained most or all components of this set and was likely capable of performing meiotic recombination using near-universal meiotic machinery.
Collapse
|