Phylogeographic evidence of cognate recognition site patterns and transformation efficiency differences in H. pylori: theory of strain dominance

BMC Microbiology

Research Article

Bodo Linz¹  María Gloria Domínguez-Bello²  Ana Maldonado-Contreras³  Luis Pericchi⁴  Xue-Song Zhang⁵  Martin J Blaser⁶  Teresa Alarcón⁷  Monica Contreras⁸  Shrinivasrao P Mane⁹ 

[1] Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA;Department of Biology, University of Puerto Rico, Río Piedras, San Juan, PR, USA;Department of Medicine, New York University Langone Medical Center, Manhattan, NY, USA;Department of Biology, University of Puerto Rico, Río Piedras, San Juan, PR, USA;Microbiology and Physiological Systems Department, University of Massachusetts Medical School, Worcester, MA, USA;Department of Mathematic, University of Puerto Rico, Río Piedras, San Juan, USA;Department of Medicine, New York University Langone Medical Center, Manhattan, NY, USA;Department of Medicine, New York University Langone Medical Center, Manhattan, NY, USA;New York Harbor Veterans Affairs Medical Center, Manhattan, NY, USA;Servicio de Microbiología, Hospital Universitario de la Princesa, Madrid, Spain;Venezuelan Institute of Scientific Research (IVIC), San Antonio de los Altos, Venezuela;Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA, USA;

关键词: H. pylori;    Haplotypes;    Restriction-Modification system;    Recombination;   

DOI  :  10.1186/1471-2180-13-211

 received in 2013-02-20, accepted in 2013-08-28,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundHelicobacter pylori has diverged in parallel to its human host, leading to distinct phylogeographic populations. Recent evidence suggests that in the current human mixing in Latin America, European H. pylori (hpEurope) are increasingly dominant at the expense of Amerindian haplotypes (hspAmerind). This phenomenon might occur via DNA recombination, modulated by restriction-modification systems (RMS), in which differences in cognate recognition sites (CRS) and in active methylases will determine direction and frequency of gene flow. We hypothesized that genomes from hspAmerind strains that evolved from a small founder population have lost CRS for RMS and active methylases, promoting hpEurope’s DNA invasion. We determined the observed and expected frequencies of CRS for RMS in DNA from 7 H. pylori whole genomes and 110 multilocus sequences. We also measured the number of active methylases by resistance to in vitro digestion by 16 restriction enzymes of genomic DNA from 9 hpEurope and 9 hspAmerind strains, and determined the direction of DNA uptake in co-culture experiments of hspAmerind and hpEurope strains.ResultsMost of the CRS were underrepresented with consistency between whole genomes and multilocus sequences. Although neither the frequency of CRS nor the number of active methylases differ among the bacterial populations (average 8.6 ± 2.6), hspAmerind strains had a restriction profile distinct from that in hpEurope strains, with 15 recognition sites accounting for the differences. Amerindians strains also exhibited higher transformation rates than European strains, and were more susceptible to be subverted by larger DNA hpEurope-fragments than vice versa.ConclusionsThe geographical variation in the pattern of CRS provides evidence for ancestral differences in RMS representation and function, and the transformation findings support the hypothesis of Europeanization of the Amerindian strains in Latin America via DNA recombination.

【 授权许可】

Unknown   
© Maldonado-Contreras et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.