Capacity of Helicobacter pylori to generate ionic gradients at low pH is similar to that of bacteria which grow under strongly acidic conditions

Matin, Abdul; Zychlinsky, E; Keyhan, M.; Sachs, George

doi:10.1128/iai.64.4.1434-1436.1996

Cited by 35 publications

(7 citation statements)

References 20 publications

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“…pylori (5). Similarly, this is consistent with the capacity of H. pylori to survive and persist in acidic medium as low as pH 3.0 by maintaining a constant transmembrane proton motive force (7).…”

supporting

confidence: 82%

Adherence Protects the Binding Sites of Helicobacter pylori Urease from Acid‐Induced Damage

Icatlo

Yokoyama

Kuroki

et al. 2000

Microbiology and Immunology

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Colonizationby Helicobacter pylori partly depends on acid-dependent adherence by urease to gastric mucin. To further verify the relevance of urease adherence to colonization, the influence of acidity on the binding sites of H. pylori urease was investigated. When enzyme-based in vitro ligand capture assays were used, the effect of acidity on the binding site of H. pylori urease was determined against a backdrop medium consisting of acidic buffers simulating the luminal side of gastric mucus. A high degree of stability was exhibited by adherent urease, suggesting a pivotal role by the denatured enzyme in the persistence of the bacterium within the acidified compartment of gastric mucus.

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supporting

confidence: 82%

Adherence Protects the Binding Sites of Helicobacter pylori Urease from Acid‐Induced Damage

Icatlo

Yokoyama

Kuroki

et al. 2000

Microbiology and Immunology

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“…As it enters the gastric environment by oral ingestion, the organism is transiently subjected to the extreme pH of the lumen side of the gastric mucous layer (pH ϳ2). The survival of H. pylori in acidic environments is probably due to its ability to establish a positive inside-membrane potential 37 and subsequently to modify its microenvironment through the action of urease and the release of factors that inhibit acid production by parietal cells 5 . A switch in membrane polarity provides an electrical barrier that prevents the entry of protons (H + ).…”

Section: Acidity Ph and Acid Tolerancementioning

confidence: 99%

The complete genome sequence of the gastric pathogen Helicobacter pylori

Tomb¹,

White²,

Kerlavage³

et al. 1997

Nature

3,258

3,183

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Helicobacter pylori, strain 26695, has a circular genome of 1,667,867 base pairs and 1,590 predicted coding sequences. Sequence analysis indicates that H. pylori has well-developed systems for motility, for scavenging iron, and for DNA restriction and modification. Many putative adhesins, lipoproteins and other outer membrane proteins were identified, underscoring the potential complexity of host-pathogen interaction. Based on the large number of sequence-related genes encoding outer membrane proteins and the presence of homopolymeric tracts and dinucleotide repeats in coding sequences, H. pylori, like several other mucosal pathogens, probably uses recombination and slipped-strand mispairing within repeats as mechanisms for antigenic variation and adaptive evolution. Consistent with its restricted niche, H. pylori has a few regulatory networks, and a limited metabolic repertoire and biosynthetic capacity. Its survival in acid conditions depends, in part, on its ability to establish a positive inside-membrane potential in low pH.

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“…Therefore, both antiporters may be evolutionarily selected for their living environment. Based on previous studies [13, 21–23], one possible explanation for the survival of H. pylori in the gastric mucosa layer (pH ∼2) is that the electric potential inside this bacterium is positive, which would prevent the influx of H + from the acidic environment. The mechanism responsible for forming the inside positive potential is unclear.…”

Section: Discussionmentioning

confidence: 99%

Expression of functional Na⁺/H⁺ antiporters of Helicobacter pylori in antiporter‐deficient Echerichia coli mutants

et al. 1999

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An open reading frame with a sequence homologous to Escherichia coli Na + /H + antiporter A (ENhaA) was found in the total genomic sequence of Helicobacter pylori, a pathogenic bacterium of gastric inflammation, and was named HNhaA. The primary sequences and the hydropathy profiles of ENhaA and HNhaA were very homologous except for one additional region found in HNhaA. This sequence has about 40 hydrophilic amino acid residues inserted at the position next to residue 235 of ENhaA which corresponds to residue 245 of HNhaA. HNhaA was expressed in E. coli mutants deficient in Na + /H + antiporters and complemented the salt-sensitive phenotype of the mutants. Membrane vesicles prepared from these transformants of HNhaA using mutants deficient in the antiporters had the antiporter activities. Surprisingly, the antiporter activity in the transformant membranes was high at acidic and neutral pH, while ENhaA did not function at these pHs. A hydrophilic region around residue 235 in ENhaA and the additional hydrophilic region of about 40 residues in the same region found in HNhaA might be responsible for this difference in activity by acting as putative pH sensors.z 1999 Federation of European Biochemical Societies.

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Capacity of Helicobacter pylori to generate ionic gradients at low pH is similar to that of bacteria which grow under strongly acidic conditions

Cited by 35 publications

References 20 publications

Adherence Protects the Binding Sites of Helicobacter pylori Urease from Acid‐Induced Damage

Adherence Protects the Binding Sites of Helicobacter pylori Urease from Acid‐Induced Damage

The complete genome sequence of the gastric pathogen Helicobacter pylori

Expression of functional Na⁺/H⁺ antiporters of Helicobacter pylori in antiporter‐deficient Echerichia coli mutants

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Capacity of Helicobacter pylori to generate ionic gradients at low pH is similar to that of bacteria which grow under strongly acidic conditions

Cited by 35 publications

References 20 publications

Adherence Protects the Binding Sites of Helicobacter pylori Urease from Acid‐Induced Damage

Adherence Protects the Binding Sites of Helicobacter pylori Urease from Acid‐Induced Damage

The complete genome sequence of the gastric pathogen Helicobacter pylori

Expression of functional Na+/H+ antiporters of Helicobacter pylori in antiporter‐deficient Echerichia coli mutants

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Expression of functional Na⁺/H⁺ antiporters of Helicobacter pylori in antiporter‐deficient Echerichia coli mutants