Article

Helicobacter pylori: recombination, population structure and human migrations

Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl-Neuberg-Str 1, D-30625 Hannover, Germany.
International Journal of Medical Microbiology (Impact Factor: 3.61). 10/2004; 294(2-3):133-9. DOI: 10.1016/j.ijmm.2004.06.014
Source: PubMed

ABSTRACT

Helicobacter pylori shows extensive genetic diversity and variability due to frequent intraspecific recombination during mixed infection. In the last years, modern genetic and genomic technology as well as cutting-edge population genetic analysis have been used to investigate the population structure and genetic variability of this pathogen. This review article summarizes recent developments in this rapidly moving field.

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    • "H. pylori are highly adapted to survive in the extreme acidic environment in the human stomach and can penetrate the mucous layer[16]. Systemic understanding of the mechanism underlying inflammation is important to find new antibiotics specific for H. pylori[21]. Over the past few decades, medical therapy for H. pylori infection has relied on a proton pump inhibitor (PPI) mixed with two antibiotics for two weeks222324. "
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    ABSTRACT: Due to the widespread and increasing appearance of antibiotic resistance, a new strategy is needed for developing novel antibiotics. Especially, there are no specific antibiotics for Helicobacter pylori (H. pylori). H. pylori are bacteria that live in the stomach and are related to many serious gastric problems such as peptic ulcers, chronic gastritis, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Because of its importance as a human pathogen, it's worth studying the structure and function of the proteins from H. pylori. After the sequencing of the H. pylori strain 26695 in 1997, more than 1,600 genes were identified from H. pylori. Until now, the structures of 334 proteins from H. pylori have been determined. Among them, 309 structures were determined by X-ray crystallography and 25 structures by Nuclear Magnetic Resonance (NMR), respectively. Overall, the structures of large proteins were determined by X-ray crystallography and those of small proteins by NMR. In our lab, we have studied the structural and functional characteristics of small proteins from H. pylori. In this review, 25 NMR structures of H. pylori proteins will be introduced and their structure-function relationships will be discussed.
    Preview · Article · Nov 2013 · Molecules
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    • "It is recognised that the distribution of some bacteria may be related to geographical patterns, such as climatic zones and movement of human populations [9–11]. However, the spatial distribution of genetic variants can shed light on pathogen evolution and transmission. "
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    ABSTRACT: Technological advances in high-throughput genome sequencing have led to an enhanced appreciation of the genetic diversity found within populations of pathogenic bacteria. Methods based on single nucleotide polymorphisms (SNPs) and insertions or deletions (indels) build upon the framework established by multi-locus sequence typing (MLST) and permit a detailed, targeted analysis of variation within related organisms. Robust phylogenetics, when combined with epidemiologically informative data, can be applied to study ongoing temporal and geographical fluctuations in bacterial pathogens. As genome sequencing, SNP detection and geospatial information become more accessible these methods will continue to transform the way molecular epidemiology is used to study populations of bacterial pathogens.
    Preview · Article · Oct 2010 · Current opinion in microbiology
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    • "Bacteria represent a globally ubiquitous domain of life, exhibiting a high degree of functional diversity (Nealson, 1997); however, investigation into the vertical transmission of information via recombination (Milkman, 1997; Coenye & LiPuma, 2003; Suerbaum & Achtman, 2004; Coscolla & Gonzalez-Candelas, 2007) and mutation (Lawrence & Ochman , 1998) has failed to account for this diversity (Syvanen, 1994; Davison, 1999). Comparative analysis of variation in bacterial genomes has provided evidence that adaptive evolution is largely facilitated by lateral gene transfer (LGT). "
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    ABSTRACT: The integron/gene cassette system contributes to lateral gene transfer of genetic information in bacterial communities, with gene cassette-encoded proteins potentially playing an important role in adaptation to stress. Class 1 integrons are a particularly important class as they themselves seem to be broadly disseminated among the Proteobacteria and have an established role in the spread of antibiotic resistance genes. The abundance and structure of class 1 integrons in freshwater sediment bacterial communities was assessed through sampling of 30 spatially distinct sites encompassing different substrate and catchment types from the Greater Melbourne Area of Victoria, Australia. Real-time PCR was used to demonstrate that the abundance of intI1 was increased as a result of ecosystem perturbation, indicated by classification of sample locations based on the catchment type and a strong positive correlation with the first principal component factor score, comprised primarily of the heavy metals zinc, mercury, lead and copper. Additionally, the abundance of intI1 at sites located downstream from treated sewage outputs was associated with the percentage contribution of the discharge to the basal flow rate. Characterization of class 1 integrons in bacteria cultured from selected sediment samples identified an association with complete Tn402-like transposition modules, and the potential for coselection of heavy-metal and antibiotic resistance mechanisms in benthic environments.
    Full-text · Article · Apr 2010 · FEMS Microbiology Ecology
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