Host specificity of ribosomal DNA variation in sylvatic Trypanosoma cruzi from North America

Clark, C. Graham; Oj, Pung

doi:10.1016/0166-6851(94)90052-3

Cited by 72 publications

(13 citation statements)

References 10 publications

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“…Contrastingly, strains from Mexico and Central America (Guatemala) have been characterized as TcI (both) and TcIV (Guatemala only), with a clear predominance of TcI isolates [36]–[39]. Isolates from the United States, have also been characterized only as TcI or TcIV [34], [40], [41]. Further confirming the paucity of genotypes in North America, in the current study, sequences of additional gene targets had sequence identity only to either TcI or TcIV.…”

Section: Discussionsupporting

confidence: 65%

Genetic Variation and Exchange in Trypanosoma cruzi Isolates from the United States

et al. 2013

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Trypanosoma cruzi, the causative agent of Chagas disease, is a multiclonal parasite with high levels of genetic diversity and broad host and geographic ranges. Molecular characterization of South American isolates of T. cruzi has demonstrated homologous recombination and nuclear hybridization, as well as the presence of 6 main genetic clusters or “discrete typing units” (DTUs). Few studies have extensively investigated such exchange events and genetic diversity in North American isolates. In the current study, we genetically characterized over 50 US isolates from wildlife reservoirs (e.g., raccoons, opossums, armadillos, skunks), domestic dogs, humans, nonhuman primates, and reduviid vectors from nine states (TX, CA, OK, SC, FL, GA, MD, LA, TN) using a multilocus sequencing method. Single nucleotide polymorphisms were identified in sequences of the mismatch-repair class 2 (MSH2) and Tc52 genes. Typing based on the two genes often paralleled genotyping by classic methodologies using mini-exon and 18S and 24Sα rRNA genes. Evidence for genetic exchange was obtained by comparing sequence phylogenies of nuclear and mitochondrial gene targets, dihydrofolate reductase-thymidylate synthase (DHFR-TS) and the cytochrome oxidase subunit II- NADH dehydrogenase subunit I region (COII-ND1), respectively. We observed genetic exchange in several US isolates as demonstrated by incongruent mitochondrial and nuclear genes phylogenies, which confirms a previous finding of a single genetic exchange event in a Florida isolate. The presence of SNPs and evidence of genetic exchange illustrates that strains from the US are genetically diverse, even though only two phylogenetic lineages have been identified in this region.

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Section: Discussionsupporting

confidence: 65%

Genetic Variation and Exchange in Trypanosoma cruzi Isolates from the United States

et al. 2013

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“…This T. cruzi genotype was described by its heterozygous profile of the isoenzyme glucose phosphate isomerase, which gave important information long ago (Apt et al, 1987;Brenière et al, 1989). The majority of the molecular studies on T. cruzi that started to be conducted approximately a decade later confirmed the differentiation into the two main (and parental) groups, T. cruzi TcI (Z1) and TcII (Z2) (Clark and Pung, 1994;Tibayrenc, 1995;Souto et al, 1996).…”

Section: T Cruzi Genotypes and Its Ecology: A Phenomenon Not Yet Fulmentioning

confidence: 99%

Landmarks of the Knowledge and Trypanosoma cruzi Biology in the Wild Environment

Jansen

Xavier

Roque

2020

Front. Cell. Infect. Microbiol.

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Trypanosomatids are ancient parasitic eukaryotes that still maintain prokaryotic characteristics. Trypanosoma cruzi, a primarily wild mammal parasite, infected humans already long before European colonization of the Americas. T. cruzi heterogeneity remains an unsolved question, and until now, it has still not been possible to associate T. cruzi genotypes with any biological or epidemiological feature. One of the first biochemical attempts to cluster the T. cruzi subpopulations recognized three main subpopulations (zymodemes) that have been associated with the transmission cycles in the wild (Z1; Z3) and in the domestic environment (Z2). The description of wild mammal species harboring Z2 two decades later challenged this assemblage attempt. Currently, the genotypes of T. cruzi are assembled in seven discrete typing units (DTUs). The biology of T. cruzi still shows novelties such as the description of epimastigotes multiplying and differentiating to metacyclic trypomastigotes in the lumen of the scent glands of Didelphis spp. and the capacity of the true meiosis in parallel to clonal reproduction. The study of the transmission cycle among wild animals has broken paradigms and raised new questions: (i) the interaction of the T. cruzi DTUs with each of its mammalian host species displays peculiarities; (ii) the impact of mixed genotypes and species on the transmissibility of one or another species or on pathogenesis is still unknown; (iii) independent T. cruzi transmission cycles may occur in the same forest fragment; (iv) the capacity to act as a reservoir depends on the peculiarities of the host species and the parasite genotype; and (v) faunistic composition is a defining trait of the T. cruzi transmission cycle profile. The development of models of environmental variables that determine the spatial distribution of the elements that make up T. cruzi transmission by spatial analysis, followed by map algebra and networking, are the next steps toward interpreting and dealing with the new profile of Chagas disease with its many peculiarities. There is no way to solve this neglected disease once and for all if not through a multidisciplinary look that takes into account all kinds of human and animal activities in parallel to environmental variations.

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“…Initial pioneering work applied multilocus enzyme electrophoresis (MLEE) techniques [12], [13], [14], [15], [16], [17], [18], [19], [20] revealing the remarkable genetic heterogeneity of this parasite. Subsequently, several PCR-based typing assays have been designed to differentiate the main DTUs [21], [22], [23], [24] and more recently, combinations of PCR-RFLP schemes have been published [25], [26], [27]. Some approaches based on DTU characterisation by direct sequential PCR amplifications from blood and tissue samples are also promising, although various sensitivity and reliability issues need to be resolved [28], [29], [30].…”

Section: Introductionmentioning

confidence: 99%

Optimized Multilocus Sequence Typing (MLST) Scheme for Trypanosoma cruzi

et al. 2014

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Trypanosoma cruzi, the aetiological agent of Chagas disease possess extensive genetic diversity. This has led to the development of a plethora of molecular typing methods for the identification of both the known major genetic lineages and for more fine scale characterization of different multilocus genotypes within these major lineages. Whole genome sequencing applied to large sample sizes is not currently viable and multilocus enzyme electrophoresis, the previous gold standard for T. cruzi typing, is laborious and time consuming. In the present work, we present an optimized Multilocus Sequence Typing (MLST) scheme, based on the combined analysis of two recently proposed MLST approaches. Here, thirteen concatenated gene fragments were applied to a panel of T. cruzi reference strains encompassing all known genetic lineages. Concatenation of 13 fragments allowed assignment of all strains to the predicted Discrete Typing Units (DTUs), or near-clades, with the exception of one strain that was an outlier for TcV, due to apparent loss of heterozygosity in one fragment. Monophyly for all DTUs, along with robust bootstrap support, was restored when this fragment was subsequently excluded from the analysis. All possible combinations of loci were assessed against predefined criteria with the objective of selecting the most appropriate combination of between two and twelve fragments, for an optimized MLST scheme. The optimum combination consisted of 7 loci and discriminated between all reference strains in the panel, with the majority supported by robust bootstrap values. Additionally, a reduced panel of just 4 gene fragments displayed high bootstrap values for DTU assignment and discriminated 21 out of 25 genotypes. We propose that the seven-fragment MLST scheme could be used as a gold standard for T. cruzi typing, against which other typing approaches, particularly single locus approaches or systematic PCR assays based on amplicon size, could be compared.

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Host specificity of ribosomal DNA variation in sylvatic Trypanosoma cruzi from North America

Cited by 72 publications

References 10 publications

Genetic Variation and Exchange in Trypanosoma cruzi Isolates from the United States

Genetic Variation and Exchange in Trypanosoma cruzi Isolates from the United States

Landmarks of the Knowledge and Trypanosoma cruzi Biology in the Wild Environment

Optimized Multilocus Sequence Typing (MLST) Scheme for Trypanosoma cruzi

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