Helicobacter pylori
Ontology highlight
ABSTRACT:
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| DRR060197_1.fastq.gz | Fastqsanger.gz | |||
| DRR060197_2.fastq.gz | Fastqsanger.gz | |||
| DRR060198_1.fastq.gz | Fastqsanger.gz | |||
| DRR060198_2.fastq.gz | Fastqsanger.gz | |||
| DRR060199_1.fastq.gz | Fastqsanger.gz |
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Similar Datasets
Project description:Helicobacter pylori colonizes the stomach of half of the world's population, causing a wide spectrum of disease ranging from asymptomatic gastritis to ulcers to gastric cancer. Although the basis for these diverse clinical outcomes is not understood, more severe disease is associated with strains harboring a pathogenicity island. To characterize the genetic diversity of more and less virulent strains, we examined the genomic content of 15 H. pylori clinical isolates by using a whole genome H. pylori DNA microarray. We found that a full 22% of H. pylori genes are dispensable in one or more strains, thus defining a minimal functional core of 1281 H. pylori genes. While the core genes encode most metabolic and cellular processes, the strain-specific genes include genes unique to H. pylori, restriction modification genes, transposases, and genes encoding cell surface proteins, which may aid the bacteria under specific circumstances during their long-term infection of genetically diverse hosts. We observed distinct patterns of the strain-specific gene distribution along the chromosome, which may result from different mechanisms of gene acquisition and loss. Among the strain-specific genes, we have found a class of candidate virulence genes identified by their coinheritance with the pathogenicity island. Keywords: other
2001-07-25 | GSE6 | GEO
Project description:Helicobacter pylori is a common bacterial infection. It can lead to severe stomach problems, including stomach cancer. Researchers want to look at samples of the bacteria. These H. pylori strains will be taken from chronically infected people. They want to identify the genetic and epigenetic differences in H. pylori strains. This could help predict which people who get infected with the bacteria will get stomach cancer. This could lead to the cancer being detected earlier. It could also mean less people get stomach cancer.
Objectives:
To study genetic variations of H. pylori strains based on samples from chronically infected people. To identify the features of strains that might lead to severe stomach problems or stomach cancer.
Eligibility:
People ages 30-70 years who need an upper endoscopy or who were recently diagnosed with stomach cancer
Design:
Participants will be screened by the doctor who does their procedure and a study nurse.
Participants who have endoscopy will have ~6 biopsies removed. These are tissue samples. They are about the size of a grain of rice. Participants will allow the study team to access reports from their stomach exam.
Participants with stomach cancer will donate some of the tissue that will be removed during their clinical care. They will allow the study team to access reports of their surgery. They will also allow them to access the microscope slides of their stomach.
| 2216372 | ecrin-mdr-crc
Project description:Helicobacter pylori, which is known as pathogens of various gastric diseases, have many types of genome sequence variants. That is part of the reason why pathogenesis and infection mechanisms of the H. pylori-driven gastric diseases have not been well clarified yet. Here we performed a large-scale proteome analysis to profile the heterogeneity of the proteome expression of 7 H. pylori strains by using LC/MS/MS-based proteomics approach combined with a customized database consisting of non-redundant tryptic peptide sequences derived from full genome sequences of 52 H. pylori strains. The non-redundant peptide database enabled us to identify more peptides in the database search of MS/MS data, compared with a simply merged protein database. Using the approach we performed proteome analysis of genome-unknown strains of H. pylori in as large-scale as genome-known ones. Clustering of the H. pylori strains using the proteome profiling slightly differed from the genome profiling and more clearly divided the strains into two groups based on the isolated area. Furthermore, we also identified phosphorylated proteins and sites of the H. pylori strains and obtained phosphorylation motif located in the N-terminus, which are commonly observed in bacteria.
2018-12-28 | PXD011364 | JPOST Repository
Project description:In this study, a whole-genome CombiMatrix Custom oligonucleotide tiling microarray with 90000 probes covering six sequenced Helicobacter pylori(H. pylori) genomes was designed and utilized for comparative genomic profiling of eight unsequenced strains isolated from patients with different gastroduodenal diseases in Heilongjiang province of China. Since significant genomic variation were found among these strains, an additional 76 H. pylori stains with different clinical outcomes isolated from various provinces of China were further tested by PCR to demonstrate this distinction. We observed several highly variable regions among strains of gastritis, gastric ulceration and gastric cancer. They are involved in genes associated with bacterial type I, type II and type III R-M system as well as in a virB gene neighboring the well studied cag pathogenic island. Previous studies have reported the diverse genetic characterization of this pathogenic island, but it is conserved in the strains tested by microarray in this study. Moreover, a number of genes involved in the type IV secretion system related to DNA horizontal transfer between H. pylori strains were identified based on the comparative analysis of the strain specific genes. These findings may provide new insights for discovering biomarkers for prediction of gastric diseases.
2013-11-10 | GSE32107 | GEO
Project description:In this study, a whole-genome CombiMatrix Custom oligonucleotide tiling microarray with 90000 probes covering six sequenced Helicobacter pylori(H. pylori) genomes was designed and utilized for comparative genomic profiling of eight unsequenced strains isolated from patients with different gastroduodenal diseases in Heilongjiang province of China. Since significant genomic variation were found among these strains, an additional 76 H. pylori stains with different clinical outcomes isolated from various provinces of China were further tested by PCR to demonstrate this distinction. We observed several highly variable regions among strains of gastritis, gastric ulceration and gastric cancer. They are involved in genes associated with bacterial type I, type II and type III R-M system as well as in a virB gene neighboring the well studied cag pathogenic island. Previous studies have reported the diverse genetic characterization of this pathogenic island, but it is conserved in the strains tested by microarray in this study. Moreover, a number of genes involved in the type IV secretion system related to DNA horizontal transfer between H. pylori strains were identified based on the comparative analysis of the strain specific genes. These findings may provide new insights for discovering biomarkers for prediction of gastric diseases. Here we describe the design and use of a high-density oligonucleotide microarray covering six sequenced H. pylori genomes as well as several sequenced plasmids. The performance of this microarray is evaluated, and its utility is illustrated for the hybridization of genomic DNA in order to compare eight uncharacterized H. pylori strains which have not been sequenced with the six known, sequenced strains. We utilize this microarray to identify variable genomic region among H. pylori strains isolated from patients with different gastroduodenal diseases in a Chinese patient population. H. pylori isolates from 2 patients with chronic superficial gastritis, 2 patients with atrophic gastritis, 2 patients with gastric ulcer, and 2 patients with gastric cancer were studied. All eight strains were isolated from Heilongjiang province of China. A number of variable regions with high genetic diversity was identified. 26 selected genes were validated by large scale PCR in both microarray tested strains while an additional 76 strains were isolated from eight provinces.
2013-11-10 | E-GEOD-32107 | biostudies-arrayexpress
Project description:Helicobacter pylori colonizes the stomach of half of the world's population, causing a wide spectrum of disease ranging from asymptomatic gastritis to ulcers to gastric cancer. Although the basis for these diverse clinical outcomes is not understood, more severe disease is associated with strains harboring a pathogenicity island. To characterize the genetic diversity of more and less virulent strains, we examined the genomic content of 15 H. pylori clinical isolates by using a whole genome H. pylori DNA microarray. We found that a full 22% of H. pylori genes are dispensable in one or more strains, thus defining a minimal functional core of 1281 H. pylori genes. While the core genes encode most metabolic and cellular processes, the strain-specific genes include genes unique to H. pylori, restriction modification genes, transposases, and genes encoding cell surface proteins, which may aid the bacteria under specific circumstances during their long-term infection of genetically diverse hosts. We observed distinct patterns of the strain-specific gene distribution along the chromosome, which may result from different mechanisms of gene acquisition and loss. Among the strain-specific genes, we have found a class of candidate virulence genes identified by their coinheritance with the pathogenicity island.
2001-07-25 | E-GEOD-6 | biostudies-arrayexpress
Project description:Whole-genome sequencing of H. pylori strains from Vietnamese
| PRJDB3403 | ENA
Project description:Background: Helicobacter pylori has been shown to alter the secretion of gastric hormones that modulate body fat deposition. Since cag-positive H. pylori strains interact intimately with the host gastric epithelial cells and trigger higher inflammation than cag-negative strains, we hypothesized that gastric colonization with H. pylori strains without functional cagA ameliorates obesity and its complications by modulating gastric gene expression and inflammation. Methodology/Principal Findings: To test this hypothesis we examined the effects of gastric colonization on metabolic and inflammatory markers in mice infected with two isogenic strains of H. pylori: 26695 strain 98-325 (cagA+ wild-type) and its cag pathogenicity island (cagPAI) mutant strain 99-305, a knockout made by inserting a chloramphenicol resistance cassette. Only the cagPAI mutant decreased fasting blood glucose levels, improved glucose tolerance and suppressed weight gain in db/db mice and mice with diet-induced obesity. These effects were associated with increased gastric leptin levels, suppressed infiltration of macrophages, enhanced influx of regulatory T cells (Treg) in adipose tissue and suppressed gastric inflammation. Gene set enrichment analyses of gastric mucosal samples identified six differentially modulated pathways, including the Hedgehog signaling pathway that is associated with control of cellular proliferation and gastric carcinogenesis as well as the insulin signaling pathway. Conclusions/Significance: Gastric colonization with cagPAI-negative strains of H. pylori ameliorate obesity and inflammation by modulating gastric gene expression, suggesting that cag-negative H. pylori strains might be beneficial in ameliorating obesity and its co-morbidities.
2010-11-13 | GSE21833 | GEO
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells, while ATM-dependent DNA damage responses in host cells suppress genome instabilities caused by DNA breakages, which resulting in the suppression of H. pylori-induced gastric cancers. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of γ-H2AX. γ-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk.
2014-08-23 | GSE60662 | GEO
Project description:Helicobacter pylori causes chronic gastritis and avoids elimination by the immune system of the infected host. The commensal bacterium Lactobacillus acidophilus has been reported to exert beneficial effects as a supplement during H. pylori eradication therapy. In the present study, we applied whole genome microarray analysis to compare the immune response induced in murine bone marrow derived macrophages (BMDM) stimulated with L. acidophilus, H. pylori, or with both bacteria in combination
2013-07-02 | GSE42622 | GEO