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Diversity and adaptation in the adherence properties of Helicobacter pylori
Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. (Thomas Borén's group)
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Place, publisher, year, edition, pages
Umeå: Umeå universitet , 2014. , 39 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1602
Keyword [en]
Helicobacter pylori, transmission, phylogeny, native populations, bacterial adherence, BabA adhesin, receptor specificity, functional polymorphism, genetic diversity, adaptation
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
URN: urn:nbn:se:umu:diva-84597ISBN: 978-91-7459-734-9 (print)OAI: oai:DiVA.org:umu-84597DiVA: diva2:685889
Public defence
2014-01-24, Naturvetarhuset, N300, Umeå universitet, Umeå, 10:00 (English)
Opponent
Supervisors
Available from: 2014-01-10 Created: 2014-01-10 Last updated: 2014-12-17Bibliographically approved
List of papers
1. DNA-level diversity and relatedness of Helicobacter pylori strains in shantytown families in Peru and transmission in a developing-country setting.
Open this publication in new window or tab >>DNA-level diversity and relatedness of Helicobacter pylori strains in shantytown families in Peru and transmission in a developing-country setting.
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2008 (English)In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 46, no 12, 3912-3918 p.Article in journal (Refereed) Published
Abstract [en]

The efficiency of transmission of a pathogen within families compared with that between unrelated persons can affect both the strategies needed to control or eradicate infection and how the pathogen evolves. In industrialized countries, most cases of transmission of the gastric pathogen Helicobacter pylori seems to be from mother to child. An alternative model, potentially applicable among the very poor in developing countries, where infection is more common and the sanitary infrastructure is often deficient, invokes frequent transmission among unrelated persons, often via environmental sources. In the present study, we compared the genotypes of H. pylori from members of shantytown households in Peru to better understand the transmission of H. pylori in developing-country settings. H. pylori cultures and/or DNAs were obtained with informed consent by the string test (a minimally invasive alternative to endoscopy) from at least one child and one parent from each of 62 families. The random amplified polymorphic DNA fingerprints of 57 of 81 (70%) child-mother strain pairs did not match, nor did the diagnostic gene sequences (>1% DNA sequence difference), independent of the child's age (range, 1 to 39 years). Most strains from siblings or other paired family members were also unrelated. These results suggest that H. pylori infections are often community acquired in the society studied. Transmission between unrelated persons should facilitate the formation of novel recombinant genotypes by interstrain DNA transfer and selection for genotypes that are well suited for individual hosts. It also implies that the effective prevention of H. pylori infection and associated gastroduodenal disease will require anti-H. pylori measures to be applied communitywide.

National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
urn:nbn:se:umu:diva-84596 (URN)10.1128/JCM.01453-08 (DOI)18842944 (PubMedID)
Available from: 2014-01-09 Created: 2014-01-09 Last updated: 2017-12-06Bibliographically approved
2. Helicobacter pylori from Peruvian amerindians: traces of human migrations in strains from remote Amazon, and genome sequence of an Amerind strain
Open this publication in new window or tab >>Helicobacter pylori from Peruvian amerindians: traces of human migrations in strains from remote Amazon, and genome sequence of an Amerind strain
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2010 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, no 11, e15076- p.Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: The gastric pathogen Helicobacter pylori is extraordinary in its genetic diversity, the differences between strains from well-separated human populations, and the range of diseases that infection promotes.

PRINCIPAL FINDINGS: Housekeeping gene sequences from H. pylori from residents of an Amerindian village in the Peruvian Amazon, Shimaa, were related to, but not intermingled with, those from Asia. This suggests descent of Shimaa strains from H. pylori that had infected the people who migrated from Asia into The Americas some 15,000+ years ago. In contrast, European type sequences predominated in strains from Amerindian Lima shantytown residents, but with some 12% Amerindian or East Asian-like admixture, which indicates displacement of ancestral purely Amerindian strains by those of hybrid or European ancestry. The genome of one Shimaa village strain, Shi470, was sequenced completely. Its SNP pattern was more Asian- than European-like genome-wide, indicating a purely Amerind ancestry. Among its unusual features were two cagA virulence genes, each distinct from those known from elsewhere; and a novel allele of gene hp0519, whose encoded protein is postulated to interact with host tissue. More generally, however, the Shi470 genome is similar in gene content and organization to those of strains from industrialized countries.

CONCLUSIONS: Our data indicate that Shimaa village H. pylori descend from Asian strains brought to The Americas many millennia ago; and that Amerind strains are less fit than, and were substantially displaced by, hybrid or European strains in less isolated communities. Genome comparisons of H. pylori from Amerindian and other communities should help elucidate evolutionary forces that have shaped pathogen populations in The Americas and worldwide.

National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
urn:nbn:se:umu:diva-83678 (URN)10.1371/journal.pone.0015076 (DOI)21124785 (PubMedID)
Available from: 2014-01-09 Created: 2013-12-03 Last updated: 2017-12-06Bibliographically approved
3. Functional polymorphism and blood group tropism in Helicobacter pylori BabA from remote Amazon diasporas
Open this publication in new window or tab >>Functional polymorphism and blood group tropism in Helicobacter pylori BabA from remote Amazon diasporas
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(English)Manuscript (preprint) (Other academic)
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
urn:nbn:se:umu:diva-84593 (URN)
Available from: 2014-01-09 Created: 2014-01-09 Last updated: 2014-01-17Bibliographically approved
4. pH regulated H. pylori adherence: implications for persistent infection and disease
Open this publication in new window or tab >>pH regulated H. pylori adherence: implications for persistent infection and disease
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(English)Manuscript (preprint) (Other academic)
Abstract [en]

Helicobacter pylori’s BabA adhesin binds strongly to gastric mucosal ABH/Leb glycans on the stomach epithelium and overlying mucus, materials continuously shed into the acidic gastric lumen. Here we report that this binding is acid labile, acid inactivation is fully reversible; and acid lability profiles vary with BabA sequence and correlate with disease patterns. Isogenic H. pylori strains from the gastric antrum and more acidic corpus were identified that differed in acid lability of receptor binding and in sequence near BabA’s carbohydrate binding domain. We propose that reversible acid inactivation of receptor binding helps H. pylori avoid clearance by mucosal shedding, and that strain differences in acid lability affect tissue tropism and the spectrum of associated gastric diseases.

National Category
Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-21487 (URN)
Available from: 2009-04-14 Created: 2009-04-14 Last updated: 2016-05-27Bibliographically approved

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