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Molecular evolution of the VacA p55 binding domain of Helicobacter pylori in mestizos from a high gastric cancer region of Colombia

Gutiérrez Escobar, Andrés J.; Bravo, María M.; Acevedo, Orlando; Backert, Steffen (2019)

The stomach bacterium Helicobacter pylori is one of the most prevalent pathogens in humans, closely linked with serious diseases such as gastric cancer. The microbe has been associated with its host for more than 100,000 ...
Phylogenomics of Colombian Helicobacter pylori isolates

Gutiérrez-Escobar, Andrés Julián; Trujillo, Esperanza; Acevedo, Orlando; Bravo, María Mercedes (2017)

Background During the Spanish colonisation of South America, African slaves and Europeans arrived in the continent with their corresponding load of pathogens, including Helicobacter pylori. Colombian strains have been ...
Rapid evolution of the Helicobacter pylori AlpA adhesin in a high gastric cancer risk region from Colombia

Gutiérrez Escobar, Andrés Julián; Méndez Callejas, Gina; Acevedo, Orlando; Bravo, Maria Mercedes (2018)

To be able to survive, Helicobacter pylori must adhere to the gastric epithelial cells of its human host. For this purpose, the bacterium employs an array of adhesins, for example, AlpA. The adhesin AlpA has been proposed ...

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Molecular evolution of the VacA p55 binding domain of Helicobacter pylori in mestizos from a high gastric cancer region of Colombia
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Gutiérrez Escobar, Andrés J. | 2019

The stomach bacterium Helicobacter pylori is one of the most prevalent pathogens in humans, closely linked with serious diseases such as gastric cancer. The microbe has been associated with its host for more than 100,000 years and escorted modern humans out of Africa. H. pylori is predominantly transmitted within families and dispersed globally, resulting in distinct phylogeographic patterns, which can be utilized to investigate migrations and bioturbation events in human history. Latin America was affected by several human migratory waves due to the Spanish colonisation that drastically changed the genetic load and composition of the bacteria and its host. Genetic evidence indicates that independent evolutionary lines of H. pylori have evolved in mestizos from Colombia and other countries in the region during more than 500 years since colonisation. The vacuolating cytotoxin VacA represents a major virulence factor of the pathogen comprising two domains, p33 and p55, the latter of which is essential for binding to the host epithelial cell. The evolution of the VacA toxin in Colombia has been strongly biased due to the effects of Spanish colonization. However, the variation patterns and microevolution of the p55 domain have not yet been described for this population. In the present study, we determined the genetic polymorphisms and deviations in the neutral model of molecular evolution in the p55 domain of 101 clinical H. pylori isolates collected in Bogotá, a city located in Andean mountains characterized by its high gastric cancer risk and its dominant mestizo population. The microevolutionary patterns of the p55 domain were shaped by recombination, purifying and episodic diversifying positive selection. Furthermore, amino acid positions 261 and 321 in the p55 domain of VacA show a high variability among mestizos clinical subsets, suggesting that natural selection in H. pylori may operate differentially in patients with different gastric diseases.

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Phylogenomics of Colombian Helicobacter pylori isolates
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Gutiérrez-Escobar, Andrés Julián | 2017

Background During the Spanish colonisation of South America, African slaves and Europeans arrived in the continent with their corresponding load of pathogens, including Helicobacter pylori. Colombian strains have been clustered with the hpEurope population and with the hspWestAfrica subpopulation in multilocus sequence typing (MLST) studies. However, ancestry studies have revealed the presence of population components specific to H. pylori in Colombia. The aim of this study was to perform a thorough phylogenomic analysis to describe the evolution of the Colombian urban H. pylori isolates. Results A total of 115 genomes of H. pylori were sequenced with Illumina technology from H. pylori isolates obtained in Colombia in a region of high risk for gastric cancer. The genomes were assembled, annotated and underwent phylogenomic analysis with 36 reference strains. Additionally, population differentiation analyses were performed for two bacterial genes. The phylogenetic tree revealed clustering of the Colombian strains with hspWestAfrica and hpEurope, along with three clades formed exclusively by Colombian strains, suggesting the presence of independent evolutionary lines for Colombia. Additionally, the nucleotide diversity of horB and vacA genes from Colombian isolates was lower than in the reference strains and showed a significant genetic differentiation supporting the hypothesis of independent clades with recent evolution. Conclusions The presence of specific lineages suggest the existence of an hspColombia subtype that emerged from a small and relatively isolated ancestral population that accompanied crossbreeding of human population in Colombia.

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Rapid evolution of the Helicobacter pylori AlpA adhesin in a high gastric cancer risk region from Colombia
...
Gutiérrez Escobar, Andrés Julián | 2018

To be able to survive, Helicobacter pylori must adhere to the gastric epithelial cells of its human host. For this purpose, the bacterium employs an array of adhesins, for example, AlpA. The adhesin AlpA has been proposed as a major adhesin because of its critical role in human stomach colonization. Therefore, understanding how AlpA evolved could be important for the development of new diagnostic strategies. However, the genetic variation and microevolutionary patterns of alpA have not been described in Colombia. The study aim was to describe the variation patterns and microevolutionary process of alpA in Colombian clinical isolates of H. pylori. The existing polymorphisms, which are deviations from the neutral model of molecular evolution, and the genetic differentiation of the alpA gene from Colombian clinical isolates of H. pylori were determined. The analysis shows that gene conversion and purifying selection have shaped the evolution of three different variants of alpA in Colombia.

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Browsing by Author "Acevedo, Orlando"

Molecular evolution of the VacA p55 binding domain of Helicobacter pylori in mestizos from a high gastric cancer region of Colombia ﻿

Phylogenomics of Colombian Helicobacter pylori isolates ﻿

Rapid evolution of the Helicobacter pylori AlpA adhesin in a high gastric cancer risk region from Colombia ﻿

Envíos recientes

Molecular evolution of the VacA p55 binding domain of Helicobacter pylori in mestizos from a high gastric cancer region of Colombia

Phylogenomics of Colombian Helicobacter pylori isolates

Rapid evolution of the Helicobacter pylori AlpA adhesin in a high gastric cancer risk region from Colombia

Molecular evolution of the VacA p55 binding domain of Helicobacter pylori in mestizos from a high gastric cancer region of Colombia

Phylogenomics of Colombian Helicobacter pylori isolates

Rapid evolution of the Helicobacter pylori AlpA adhesin in a high gastric cancer risk region from Colombia