Implications of genetic variability of Trypanosoma cruzi for the pathogenesis of Chagas disease

O Trypanosoma cruzi, agente etiológico da doença de Chagas, apresenta elevado grau de variabilidade genética intra-específica, com possíveis implicações na forma clínica da doença, como o desenvolvimento de cardiopatia, do megaesôfago e do megacólon de forma isolada ou em associação. Este tropismo tecidual envolvido na patogênese da doença não está totalmente esclarecido. Assim, nesta revisão são abordados alguns aspectos referentes à diversidade genética dos parasitas isolados, às formas clínicas da doença de Chagas, ao processo de infecção do parasita na célula hospedeira e resposta imune. Outros aspectos também são enfocados, como os fatores imunossupressivos liberados pelo parasita que atuam na regulação das respostas imunes, a inibição da apoptose da célula hospedeira, assim como da patogênese do megaesôfago chagásico que pode estar relacionada à interação hospedeiro- parasita e sua associação com risco aumentado para o desenvolvimento do carcinoma epidermóide do esôfago. Porém, apesar dos avanços no entendimento desta doença, ainda não é possível estabelecer o verdadeiro perfil da variabilidade genética do parasita com a forma clínica da doença de Chagas.Trypanosoma cruzi, the etiological agent of Chagas disease, presents a high degree of intraspecific genetic variability, with possible implications for the clinical forms of the disease, like the development of cardiopathy, megaesophagus, and megacolon, alone or in combination. This tissue tropism involved in the pathogenesis of Chagas disease has still not been totally elucidated. Thus, the current review approaches key aspects of T. cruzi genetic diversity, the clinical forms of Chagas disease, and the infection of the host cell by the parasite and the immune response. Other aspects discussed here include the release of immunosuppressive factors by the parasite, acting in the host's immune response pathways; host cell apoptosis inhibition; the pathogenesis of chagasic megaesophagus, which can be related to host-parasite interaction; and finally the association between megaesophagus and increased risk for the development of squamous-cell esophageal carcinoma. However, despite great advances in the understanding of this disease, it is still not possible to establish the true relationship between the parasite's genetic variability and the clinical form of Chagas disease

kDNA gene signatures of Trypanosoma cruzi in blood and oesophageal mucosa from chronic chagasic patients

Trypanosoma cruzi presents a high degree of intraspecific variability, with possible implications for the pathogenesis of Chagas disease. The aim of this study was to evaluate T cruzi kDNA minicircle gene signatures using the low-stringency single-specific-primer PCR technique in both peripheral blood and oesophageal. mucosa from chronic chagasic patients, with or without megaesophagus, atone or in combination with cardiopathy and megacolon. It was not possible to identify a uniform pattern of shared bands between blood and oesophageal mucosa samples from individuals with the same clinical. form or mixed forms, suggesting multiple T. cruzi infections with differential tissue tropism. Thus, the results indicate that there is an intense intraspecific variability in the hypervariable regions of T cruzi kDNA, which has so far made it impossible to correlate the genetic profile of this structure with the clinical manifestations of Chagas disease. (C) 2008 Royal. Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. AIL rights reserved

Gene Mutations and Polymorphisms of TP53 and FHIT in Chronic Esophagitis and Esophageal Carcinoma

Aim: The aim of this study was to investigate genetic changes of the TP53 (tumor protein p53) and FHIT (fragile histidine triad) genes in precursor lesion such as chronic esophagitis (CE) and in esophageal squamous cell carcinoma (ESCC). Materials and Methods: PCR-Single Strand Conformation Polymorphism (SSCP) analysis and DNA sequencing in 30 CE and 10 ESCC specimens were performed. Results: DNA sequencing indicated two novel mutations in the TP53 exons 5 (codon 147) and 6 (codon 197) in 219 SSCP positive cases of ESCC, but no mutation was found in the CE. The SIFT (Sorting Intolerant From Tolerant) web-based program showed that missense variant at codon 197 of TP53 could affect the protein function. Additionally, polymorphisms of the TP53 exon 4 (codon 36 and 72) and of the FHIT exon 7 (codon 88) were observed in 4/11(36%) cases of CE and 619 (67%) SSCP positive cases of ESCC after DNA sequencing. Conclusion: TP53 gene mutations are not common events in CE, but are frequent in ESCC, and as polymorphisms of TP53 and FHIT may confer a greater risk for the development of esophageal carcinoma, further studies are required.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Functional characterization of 3,183 SNP markers derived from the Illumina Bovine HD panel that consistently generated missing genotypes in the Nelore breed (SFNBs).

<p>Functional characterization of 3,183 SNP markers derived from the Illumina Bovine HD panel that consistently generated missing genotypes in the Nelore breed (SFNBs).</p

IGV screenshot image.

<p>The double vertical lines indicate the BovineHD0500032585 SNP position. Colored positions indicate flanking SNPs. There are 6 non-synonymous SNPs and 1 synonymous SNP (4^th column from left).</p

Mean frequency and standard deviation of the nearest Nelore SNPs within 50bp and 100bp size bins.

<p>Mean frequency and standard deviation of the nearest Nelore SNPs within 50bp and 100bp size bins.</p

Distribution of SFNBs across bovine chromosomes.

<p>Distribution of SFNBs across bovine chromosomes.</p