The population structure of Trypanosoma cruzi: expanded analysis of 54 strains using eight polymorphic CA-repeat microsatellites

Oliveira, Riva de Paula; Melo, Anna Izabel R.; Macedo, Andréa Mara; Chiari, Égler; Pena, Sérgio Danilo Junho

doi:10.1590/s0074-02761999000700006

Cited by 29 publications

(17 citation statements)

References 16 publications

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“…The high genetic polymorphism among E. histolytica isolates described in this work, as with polymorphisms described for Leishmania and Trypanosoma cruzi (3,23,29), implies similarly diverse biological characteristics such as immunopathological effects, drug sensitivities, and vaccine attributes. The polymorphic nature of SREHP requires further attention because SREHP is being exploited as a protective immunodominant antigen (36,37).…”

Section: Discussionmentioning

confidence: 53%

Remarkable Genetic Polymorphism among Entamoeba histolytica Isolates from a Limited Geographic Area

et al. 2002

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In order to understand genetic polymorphisms among Entamoeba histolytica strains in a limited geographic area and among restricted social populations, we studied nucleotide polymorphism in DNA regions that do not encode proteins (locus 1-2 and locus 5-6) and in genes coding for chitinase and for serine-rich E. histolytica protein. Thirty E. histolytica isolates from domestically infected Japanese amebiasis patients (male homosexuals and residents in institutions for the mentally handicapped) and four reference strains were examined. PCR revealed remarkable polymorphisms in both the number and size of the PCR fragments containing these loci. Polymorphisms in lengths, types, and numbers of internal repeat units were observed in locus 1-2 and the repeat-containing region of serine-rich E. histolytica protein among the Japanese isolates. In contrast, polymorphism at locus 5-6 was observed almost exclusively in the number of repeats of a 16-nucleotide unit. The repeat-containing region of chitinase appeared to be the least polymorphic among the four loci with a single dominant genotype representing 66% (20 out of 30) of all of the isolates. Isolates obtained from male homosexuals showed a more complex genetic polymorphism than those from residents in institutions. Considering all four polymorphic loci together, all 19 Japanese isolates from male homosexuals were distinct. In contrast, all isolates obtained from mass-infection cases at a single institution had an identical genotype, suggesting that these cases were caused by a single E. histolytica strain. No significant correlation was found between genotypes and zymodemes or between genotypes and clinical presentations, e.g., colitis or liver abscess. Certain genotypes were observed with higher frequencies in male homosexuals or residents of institutions. These data indicate that genotyping of the E. histolytica isolates by using these four polymorphic loci could serve as a tool to fingerprint individual isolates. We propose that genotyping of ameba isolates should help to determine geographic origins of isolates and routes of transmission.The protozoan parasite Entamoeba histolytica causes an estimated 50 million cases of amebiasis and 40,000 to 100,000 deaths annually, placing it second only to malaria as a cause of death resulting from parasitic protozoa (33). Since the first description of amebiasis in 1878 by Lösch (17), we still do not have a proper answer to the question of why disease and symptoms develop in only 5 to 10% of those infected with E. histolytica. It has been speculated that a spectrum of virulence levels among the E. histolytica strains and variability in the host immune response against amebic invasion contribute to the outcome of amebic infection. While variation in human immune responses against amebic infection is not understood, the polymorphic structure of E. histolytica has recently been unveiled (4,7,12,28,34). These studies have identified and characterized polymorphic DNA loci, including protein-coding sequences, such as those for the...

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Section: Discussionmentioning

confidence: 53%

Remarkable Genetic Polymorphism among Entamoeba histolytica Isolates from a Limited Geographic Area

et al. 2002

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“…Genetic variability, stability and sensitivity of T. cruzi microsatellite assay -In this work we have chosen 53 monoclonal populations (see Table) among 72 T. cruzi isolates that have been typed before by microsatellite markers (Oliveira et al 1999). The hipervariability previously described for T. cruzi microsatellite loci was confirmed in this expanded analysis since no single repeated multilocus genotype was detected among the analyzed samples.…”

Section: Resultsmentioning

confidence: 99%

“…Phylogenetic inference -As previously described (Oliveira et al 1998(Oliveira et al , 1999 to make phylogenetic inferences, we assumed a stepwise mutation model for the microsatellites. As a measure of genetic distance between any two strains we used the minimum number of mutational steps necessary to transform one into the other.…”

Section: Parasites -T Cruzimentioning

confidence: 99%

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Usefulness of microsatellite typing in population genetic studies of Trypanosoma cruzi

Macedo

Pimenta

Aguiar

et al. 2001

Mem. Inst. Oswaldo Cruz

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“…Despite their high degrees of genetic variability, T. cruzi isolates can be classified into two major phylogenetic lineages: T. cruzi lineage I (T. cruzi I) and T. cruzi II (4). These lineages are very divergent, as revealed by several biological and molecular markers, including isoenzymes, 24S␣ rRNA, the miniexon gene, and microsatellite polymorphisms, among others (4,10,35,36,39,42,45,50).…”

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confidence: 99%

Probing Population Dynamics of Trypanosoma cruzi during Progression of the Chronic Phase in Chagasic Patients

et al. 2009

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Our research aimed to characterize the genetic profiles of 102 Trypanosoma cruzi isolates recently obtained from 44 chronic chagasic patients from different regions of the states of Minas Gerais and Goiás in Brazil. At least two isolates were obtained from each patient at different times in order to study the parasite population dynamics during disease progression in the chronic phase. The isolates were characterized molecularly by genotyping the 3 region of the 24S␣ rRNA, the mitochondrial cytochrome oxidase subunit 2 (COII) gene, and the intergenic region of the spliced leader intergenic region (SL-IR) gene. Seventy-seven isolates were analyzed for nine microsatellite loci. The data presented here show a strong correlation between the T. cruzi lineage II (T. cruzi II) and human infection in these regions of Brazil. Interestingly, isolates from two patients were initially characterized (by rRNA genotyping) as T. cruzi I and hybrid strains, but subsequent analyses of the COII and SL-IR genes confirmed that those isolates belonged to T. cruzi III and a hybrid group, respectively. Our results confirm the risk of misclassifying T. cruzi isolates on the basis of analysis of a single molecular marker. The microsatellite profiles showed that different isolates obtained from the same patient were genetically identical and monoclonal. Exceptions were observed for T. cruzi isolates from two patients who presented differences for the SCLE11 locus and also from two other patients who showed amplification of three peaks for a microsatellite locus (TcAAAT6), implying that they were multiclonal. On the basis of the findings of the studies described here, we were not able to establish a correlation between the clinical forms of Chagas' disease and the genetic profiles of the T. cruzi isolates.

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The population structure of Trypanosoma cruzi: expanded analysis of 54 strains using eight polymorphic CA-repeat microsatellites

Abstract: Recently we cloned and sequenced the first eight

Cited by 29 publications

References 16 publications

Remarkable Genetic Polymorphism among Entamoeba histolytica Isolates from a Limited Geographic Area

Remarkable Genetic Polymorphism among Entamoeba histolytica Isolates from a Limited Geographic Area

Usefulness of microsatellite typing in population genetic studies of Trypanosoma cruzi

Probing Population Dynamics of Trypanosoma cruzi during Progression of the Chronic Phase in Chagasic Patients

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