Outer membrane protein expression profile in Helicobacter pylori clinical isolates.

The gram-negative gastric pathogen Helicobacter pylori is equipped with an extraordinarily large set of outer membrane proteins (OMPs), whose role in the infection process is not well understood. The Hop (Helicobacter outer membrane porins) and Hor (Hop-related proteins) groups constitute a large paralogous family consisting of 33 members. The OMPs AlpA, AlpB, BabA, SabA, and HopZ have been identified as adhesins or adherence-associated proteins.

Identification of glycoprotein receptors within the human salivary proteome for the lectin-like BabA and SabA adhesins of Helicobacter pylori by fluorescence-based 2-D bacterial overlay.

Because gastric infection by Helicobacter pylori takes place via the oral route, possible interactions of this bacterium with human salivary proteins could occur. By using modified 1- and 2-D bacterial overlay, binding of H. pylori adhesins BabA and SabA to the whole range of salivary proteins was explored.

Functional and intracellular signaling differences associated with the Helicobacter pylori AlpAB adhesin from Western and East Asian strains.

Following adhesion of Helicobacter pylori to gastric epithelial cells, intracellular signaling leads to cytokine production, which causes H. pylori-related gastric injury. Two adjacent homologous genes (alpA and alpB), which encode H.

Helicobacter pylori BabA expression, gastric mucosal injury, and clinical outcome.

Background & Aims: The blood grou.

Methods: We compared the ability of published PCR-based methods to assess BabA status with BabA immunoblotting and Lewis b (Le(b)) binding activity assays. We also used immunoblotting to examine the relationship between clinical presentation and levels of BabA expression.

SabA is the H. pylori hemagglutinin and is polymorphic in binding to sialylated glycans.

Adherence of Helicobacter pylori to inflamed gastric mucosa is dependent on the sialic acid-binding adhesin (SabA) and cognate sialylated/fucosylated glycans on the host cell surface. By in situ hybridization, H. pylori bacteria were observed in close association with erythrocytes in capillaries and post-capillary venules of the lamina propria of gastric mucosa in both infected humans and Rhesus monkeys.

The novel Helicobacter pylori CznABC metal efflux pump is required for cadmium, zinc, and nickel resistance, urease modulation, and gastric colonization.

Maintaining metal homeostasis is crucial for the adaptation of Helicobacter pylori to the gastric environment. Iron, copper, and nickel homeostasis has recently been demonstrated to be required for the establishment of H. pylori infection in animal models.

Interleukin-6 induction by Helicobacter pylori in human macrophages is dependent on phagocytosis.

Background: The colonization of the gastric mucosa with Helicobacter pylori is accompanied by elevated levels of proinflammatory cytokines, such as interleukin-1 (IL-1), IL-6, and IL-8. The aim of our study was to determine the mechanisms of IL-6 stimulation in phagocytes upon H. pylori infection.

Functional and topological characterization of novel components of the comB DNA transformation competence system in Helicobacter pylori.

Helicobacter pylori is one of the most diverse bacterial species known. A rational basis for this genetic variation may be provided by its natural competence for genetic transformation and high-frequency recombination. Many bacterial competence systems have homology with proteins that are involved in the assembly of type IV pili and type II secretion systems.

Interaction between host gastric Sialyl-Lewis X and H. pylori SabA enhances H. pylori density in patients lacking gastric Lewis B antigen.

Objectives: We tested whether the interaction between host gastric Le(x) antigen and the SabA protein of H. pylori determined gastric colonization density.

Methods: A total of 145 H.

Adherence properties of Helicobacter pylori: impact on pathogenesis and adaptation to the host.

The adherence of the human gastric pathogen Helicobacter pylori to the gastric mucosa is widely assumed to play a substantial role in initial colonization and long-term persistence in the human stomach. In the past, a couple of putative adhesins were identified, most of which were members of the large outer membrane protein (OMP) family of H. pylori.

Identification and characterization of binding properties of Helicobacter pylori by glycoconjugate arrays.

The microaerophilic bacterium Helicobacter pylori is well established for its role in development of different gastric diseases. Bacterial adhesins and corresponding binding sites on the epithelial surface allow H. pylori to colonize the gastric tissue.

Correlation between Helicobacter pylori OipA protein expression and oipA gene switch status.

Polyclonal antisera to either a synthetic OipA peptide or a recombinant OipA protein detected OipA expression in Helicobacter pylori and correlated with functional oipA status determined by PCR sequence (sensitivity and specificity of >94%). Immunoblotting is a simple and accurate method for detecting expression of the important virulence factor OipA.

Structure of Helicobacter pylori catalase, with and without formic acid bound, at 1.6 A resolution.

Helicobacter pylori produces one monofunctional catalase, encoded by katA (hp0875). The crystal structure of H. pylori catalase (HPC) has been determined and refined at 1.

Identification and characterization of Helicobacter pylori genes essential for gastric colonization.

Helicobacter pylori causes one of the most common, chronic bacterial infections and is a primary cause of severe gastric disorders. To unravel the bacterial factors necessary for the process of gastric colonization and pathogenesis, signature tagged mutagenesis (STM) was adapted to H. pylori.

CagA tyrosine phosphorylation and interleukin-8 induction by Helicobacter pylori are independent from alpAB, HopZ and bab group outer membrane proteins.

In several studies Helicobacter pylori type I strains (cag-positive strains) have been described to translocate their CagA protein into epithelial cells, where it is tyrosine-phosphorylated. The intimate contact allows a Cag-dependent bacteria-to-cell signaling inducing the secretion of the chemokine interleukin-8. Although a contact between the bacterial and the eukaryotic cell is known to be necessary for these signal transduction events the bacterial adhesin and the cellular receptor are unknown, so far.

Role of the alpAB proteins and lipopolysaccharide in adhesion of Helicobacter pylori to human gastric tissue.

The attachment of the bacterial pathogen Helicobacter pylori (H. pylori) to gastric epithelial cells is commonly believed to be required for an efficient and persistent colonization of the human stomach as well as for host cell trans-membrane signaling. In the past, several putative adhesins were postulated, including the outer membrane proteins AlpAB and the bacterial lipopolysaccharide (LPS) presenting oligomeric Lewis x (Le(x)) sugar components.

Essential role of ferritin Pfr in Helicobacter pylori iron metabolism and gastric colonization.

The reactivity of the essential element iron necessitates a concerted expression of ferritins, which mediate iron storage in a nonreactive state. Here we have further established the role of the Helicobacter pylori ferritin Pfr in iron metabolism and gastric colonization. Iron stored in Pfr enabled H.

Discrimination between cases of duodenal ulcer and gastritis on the basis of putative virulence factors of Helicobacter pylori.

The BabA, cagA, and vacA statuses of 827 Helicobacter pylori isolates were used in logistic regression models to discriminate duodenal ulcer from gastritis. Only BabA was a candidate for a universal virulence factor, but the low c statistic value (0.581) indicates that none of these factors were helpful in predicting the clinical presentation.

Structural, functional and mutational analysis of the pfr gene encoding a ferritin from Helicobacter pylori.

The function of the pfr gene encoding the ferritin from Helicobacter pylori was investigated using the Fur titration assay (FURTA) in Escherichia coli, and by characterization of a pfr-deficient mutant strain of H. pylori. Nucleotide sequence analysis revealed that the pfr region is conserved among strains (> 95% nucleotide identity).