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Positive selection in the evolution of Helicobacter pylori outer membrane proteins
Nunes, Alexandra; Ménard, Armelle; Mégraud, Francis; Oleastro, MónicaHomologous recombination in Helicobacter pylori has been extensively described to occur via Outer Membrane Proteins (OMPs), regulating protein expression and generating allelic diversity, while the importance of single nucleotide polymorphisms (SNP) remains little studied. We used an OMP-encoding gene, homC, as a model to evaluate the weight of positive selection in the evolution of H. pylori, by using G200 seq...
Diversity and phylogeny of the Helicobacter pylori outer membrane protein-encod...
Cordeiro, Rita; Ménard, Armelle; Breurec, Stéphane; Mégraud, Francis; Oleastro, MónicaThe genetic diversity and evolution of the homC gene was evaluated in a panel of approximately 200 clinical and reference strains, isolated from patients from different geographical origins and presenting different gastric diseases. PCR, sequencing and bioinformatics analyses were used. All the strains tested harboured a complete homC gene at a conserved locus. Phylogenetic reconstruction of homC showed a geogr...
High worldwide conservation of a Helicobacter pylori outer membrane protein
Ménard, Armelle; Cordeiro, Rita; Breurec, Stéphane; Mégraud, Francis; Oleastro, MónicaThe genetic diversity and evolution of homD, coding for Helicobacter pylori outer membrane protein (OMP) was investigated in a panel of approximately 200 clinical and reference strains, isolated from patients from different geographical origins and presenting different gastric diseases. PCR, sequencing and bioinformatics analyses were used. The homD gene was present in all strains, at a conserved locus, and sho...
Helicobacter pylori cagA and vacA genotypes in Cuban and Venezuelan populations
Ortiz-Princz,Diana; Guariglia-Oropeza,Verónica; Ávila,Maira; Correnti,María; Perrone,Marianella; Gutierrez,Beatriz; Torres,Javier; Megraud,FrancisThe aim of this study was to determine the presence of Helicobacter pylori cytotoxin-associated gene (cagA)/vacuolating cytotoxin gene (vacA) among patients with chronic gastritis in Cuba and Venezuela. Gastric antrum biopsies were taken for culture, DNA extraction and PCR analysis. Amplification of vacA and cagA segments was performed using two regions of cagA: 349 bp were amplified with the F1/B1 primers and ...
Clinical relevance and diversity of two homologous genes encoding glycosyltrans...
Oleastro, Mónica; Andrea, Santos; Cordeiro, Rita; Nunes, Baltazar; Mégraud, Francis; Ménard, ArmelleHelicobacter pylori is known to be a major cause of peptic ulceration. The jhp0562 gene, encoding a glycosyltransferase involved in the synthesis of the lipopolysaccharide, was associated with peptic ulcer disease (PUD) in children. The beta-(1,3)-galactosyltransferase [beta-(1,3)GalT] gene (jhp0563), involved in Lewis (Le) antigen expression, is highly similar to jhp0562. The clinical significance and diversit...
Geographic distribution of methyltransferases of Helicobacter pylori: evidence ...
Vale, Filipa; Mégraud, Francis; Vítor, Jorge M. B.Background Helicobacter pylori colonizes the human stomach and is associated with gastritis, peptic ulcer, and gastric cancer. This ubiquitous association between H. pylori and humans is thought to be present since the origin of modern humans. The H. pylori genome encodes for an exceptional number of restriction and modifications (R-M) systems. To evaluate if R-M systems are an adequate tool to determine the ge...
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