scholarly journals ADP heptose, a novel pathogen-associated molecular pattern associated with Helicobacter pylori type 4 secretion

2018 ◽  
Author(s):  
Lennart Pfannkuch ◽  
Robert Hurwitz ◽  
Jan Traulsen ◽  
Paul Kosma ◽  
Monika Schmid ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Gram Negative Bacteria ◽  
Gene Encoding ◽  
Gram Negative ◽  
Human Epithelial Cells ◽  
Molecular Pattern ◽  
Pathogen Associated Molecular Pattern ◽  
Encoding Gene ◽  
H Pylori

AbstractThe gastric pathogen Helicobacter pylori activates the NF-κB pathway in human epithelial cells via the α-kinase 1 (Alpk1)–TIFA axis. We and others have previously shown that heptose 1,7-bisphosphate (HBP) acts as a pathogen-associated molecular pattern (PAMP). HBP is an intermediate of lipopolysaccharide (LPS) synthesis in H. pylori and other gram-negative bacteria. Deletion of the hldE (rfaE) gene encoding the enzyme responsible for HBP synthesis, as well as deletion of further upstream genes, causes loss of NF-κB stimulation by H. pylori, while deletion of the downstream phosphatase encoding gene gmhB does not. This has led to the conclusion that HBP is the PAMP responsible for NF-κB induction. Here, our attempts to identify HBP in lysates of H. pylori revealed surprisingly low amounts that fail to explain NF-κB activation. Instead, we identified ADP heptose, a major downstream metabolite of HdlE, as the predominant PAMP in H. pylori lysates, exhibiting ∼100-fold stronger activity compared to HBP. It therefore appears that synthesis of ADP heptose from HBP in H. pylori occurs independently of GmhB. The data lead us to conclude that ADP heptose constitutes the key PAMP, secreted via the pathogen’s cagPAI encoded type 4 secretion (T4SS).

scholarly journals In Vitro Anti-Helicobacter pyloriActivities of New Rifamycin Derivatives, KRM-1648 and KRM-1657

1999 ◽  
Vol 43 (5) ◽  
pp. 1072-1076 ◽  
Author(s):  
Junko K. Akada ◽  
Mutsunori Shirai ◽  
Kenji Fujii ◽  
Kiwamu Okita ◽  
Teruko Nakazawa
Keyword(s):  
Helicobacter Pylori ◽  
Cell Lysis ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Bactericidal Activities ◽  
H Pylori ◽  
Time Kill

ABSTRACT The new rifamycin derivatives KRM-1657 and KRM-1648 were evaluated for their in vitro antimicrobial activities against 44 strains ofHelicobacter pylori. Although the drugs were not very active against other gram-negative bacteria, the MICs at which 90% of isolates are inhibited for these drugs were lower (0.002 and 0.008 μg/ml, respectively) than those of amoxicillin and rifampin forH. pylori. Time-kill studies revealed that the bactericidal activities of these agents were due to cell lysis. The results presented here indicate that these new rifamycin derivatives may be useful for the eradication of H. pylori infections.

scholarly journals Helicobacter pylori Peptidoglycan Modifications Confer Lysozyme Resistance and Contribute to Survival in the Host

mBio ◽  
2012 ◽  
Vol 3 (6) ◽  
Author(s):  
Ge Wang ◽  
Leja F. Lo ◽  
Lennart S. Forsberg ◽  
Robert J. Maier
Keyword(s):  
Cell Wall ◽  
Helicobacter Pylori ◽  
Double Mutant ◽  
Lytic Enzyme ◽  
Permeability Barrier ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
H Pylori ◽  
Modification Enzyme

ABSTRACTThe prominent host muramidase lysozyme cleaves bacterial peptidoglycan (PG), and the enzyme is abundant in mucosal secretions. The lytic enzyme susceptibility of Gram-negative bacteria and mechanisms they use to thwart lytic enzyme activity are poorly studied. We previously characterized aHelicobacter pyloriPG modification enzyme, an N-deacetylase (PgdA) involved in lysozyme resistance. In this study, another PG modification enzyme, a putative PG O-acetyltransferase (PatA), was identified. Mass spectral analysis of the purified PG demonstrated that apatAstrain contained a greatly reduced amount of acetylated muropeptides, indicating a role for PatA inH. pyloriPG O-acetylation. The PG modification mutant strains (pgdA,patA, orpgdA patA) were more susceptible to lysozyme killing than the parent, but this assay required high lysozyme levels (up to 50 mg/ml). However, addition of host lactoferrin conferred lysozyme sensitivity toH. pylori, at physiologically relevant concentrations of both host components (3 mg/ml lactoferrin plus 0.3 mg/ml lysozyme). ThepgdA patAdouble mutant strain was far more susceptible to lysozyme/lactoferrin killing than the parent. Peptidoglycan purified from apgdA patAmutant was five times more sensitive to lysozyme than PG from the parent strain, while PG from both single mutants displayed intermediate sensitivity. Both sensitivity assays for whole cells and for purified PGs indicated that the modifications mediated by PgdA and PatA have a synergistic effect, conferring lysozyme tolerance. In a mouse infection model, significant colonization deficiency was observed for the double mutant at 3 weeks postinoculation. The results show that PG modifications affect the survival of a Gram-negative pathogen.IMPORTANCEPathogenic bacteria evade host antibacterial enzymes by a variety of mechanisms, which include resisting lytic enzymes abundant in the host. Enzymatic modifications to peptidoglycan (PG, the site of action of lysozyme) are a known mechanism used by Gram-positive bacteria to protect against host lysozyme attack. However, Gram-negative bacteria contain a thin layer of PG and a recalcitrant outer membrane permeability barrier to resist lysis, so molecular modifications to cell wall structure in order to combat lysis remain largely unstudied. Here we show that twoHelicobacter pyloriPG modification enzymes (PgdA and PatA) confer a clear protective advantage to a Gram-negative bacterium. They protect the bacterium from lytic enzyme degradation, albeit via different PG modification activities. Many pathogens are Gram negative, so some would be expected to have a similar cell wall-modifying strategy. Understanding such strategies may be useful for combating pathogen growth.

scholarly journals Anti-Helicobacter pylori Activity of the Methanolic Extract of Geum iranicum and its Main Compounds

2012 ◽  
Vol 67 (3-4) ◽  
pp. 172-180 ◽  
Author(s):  
Somayeh Shahani ◽  
Hamid R. Monsef-Esfahani ◽  
Soodabeh Saeidnia ◽  
Parastoo Saniee ◽  
Farideh Siavoshi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Phenolic Glycoside ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Aqueous Fraction ◽  
Gram Negative ◽  
Effective Fraction ◽  
H Pylori

Geum iranicum Khatamsaz, belonging to the Rosaceae family, is an endemic plant of Iran. The methanol extract of the roots of this plant showed signifi cant activity against one of the clinical isolates of Helicobacter pylori which was resistant to metronidazole. The aim of this study was the isolation and evaluation of the major compounds of G. iranicum effective against H. pylori. The compounds were isolated using various chromatographic methods and identifi ed by spectroscopic data (1H and 13C NMR, HMQC, HMBC, EI-MS). An antimicrobial susceptibility test was performed employing the disk diffusion method against clinical isolates of H. pylori and a micro dilution method against several Gram-positive and Gram-negative bacteria; additionally the inhibition zone diameters (IZD) and minimum inhibitory concentrations (MIC) values were recorded. Nine compounds were isolated: two triterpenoids, uvaol and niga-ichigoside F1, three sterols, β-sitosterol, β-sitosteryl acetate, and β-sitosteryl linoleate, one phenyl propanoid, eugenol, one phenolic glycoside, gein, one fl avanol, (+)-catechin, and sucrose. The aqueous fraction, obtained by partitioning the MeOH extract with water and chloroform, was the most effective fraction of the extract against all clinical isolates of H. pylori. Further investigation of the isolated compounds showed that eugenol was effective against H. pylori but gein, diglycosidic eugenol, did not exhibit any activity against H. pylori. The subfraction D4 was the effective fraction which contained tannins. It appeared that tannins were probably the active compounds responsible for the anti-H. pylori activity of G. iranicum. The aqueous fraction showed a moderate inhibitory activity against both Gram-positive and Gram-negative bacteria. The MIC values indicated that Gram-positive bacteria including Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis are more susceptible than Gram-neagative bacteria including Escherichia coli and Pseudomonas aeruginosa.

scholarly journals Overview of Helicobacter pylori Detection Using Rapid Urease Test and Giemsa Modification Staining in Chronic Tonsillitis Patients

2020 ◽  
Vol 8 (B) ◽  
pp. 1105-1109
Author(s):  
Ade Asyari ◽  
Ferdy Azman ◽  
Novialdi Novialdi ◽  
Aziz Djamal ◽  
Hafni Bachtiar ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Descriptive Study ◽  
Chronic Tonsillitis ◽  
Rapid Urease Test ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Tonsillar Tissue ◽  
Urease Test ◽  
Tonsil Tissue ◽  
H Pylori

BACKGROUND: Helicobacter pylori (H. pylori) is a Gram-negative bacteria and has been known for its role in causing gastric infection aused diseases such as gastric ulcer. H. pylori also implied to play a role in chronic tonsillitis, but this theory remains controversial. Many researches have different and contradictory results due to difficulty to accurately detect H. pylori in tonsillar tissue. There is still no appropriate method that able to detect H. pylori in tonsil tissue. AIM: The aim of the study was to detect H. pylori colonization in chronic tonsillitis and understand some of the methods of examination that can be done to detect H. pylori in tonsillar tissue. METHODS: This study is a descriptive study conducted on 25 respondents. Each sample was taken from patients with chronic tonsillitis who underwent tonsillectomy. Then, the rapid urease test (RUT) and the Giemsa modification staining were carried out to determine the presence of H. pylori. RESULTS: There were 19 people (76%) positive and 6 people (24%) negative for H. pylori using RUT. On examination with Giemsa modification staining obtained 19 people (76%) positive and 6 people (24%) negative for H. pylori. CONCLUSION: H. pylori can be found in most of chronic tonsillitis. Combination RUT and Giemsa modification staining examination can be a good option in detecting H. pylori in chronic tonsillitis.

scholarly journals Effects ofHelicobacter pyloriand Heat Shock Protein 70 on the Proliferation of Human Gastric Epithelial Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Liping Tao ◽  
Hai Zou ◽  
Zhimin Huang
Keyword(s):  
Helicobacter Pylori ◽  
Heat Shock ◽  
Epithelial Cells ◽  
Heat Shock Protein ◽  
Mtt Assay ◽  
Heat Shock Protein 70 ◽  
Hsp70 Expression ◽  
Gastric Epithelial Cells ◽  
Ags Cells ◽  
H Pylori

Infection ofHelicobacter pylori (H. pylori)changed the proliferation of gastric epithelial cells and decreased the expression of heat shock protein 70 (HSP70). However, the effects ofH. pylorion the proliferation of gastric epithelial cells and the roles of HSP70 during the progress need further investigation.Objective.To investigate the effects ofHelicobacter pylori (H. pylori)and heat shock protein 70 (HSP70) on the proliferation of human gastric epithelial cells.Methods. H. pyloriand a human gastric epithelial cell line (AGS) were cocultured. The proliferation of AGS cells was quantitated by an MTT assay, and the expression of HSP70 in AGS cells was detected by Western blotting. HSP70 expression in AGS cells was silenced by small interfering RNA (siRNA) to investigate the role of HSP70. ThesiRNA-treated AGS cells were cocultured withH. pyloriand cell proliferation was measured by an MTT assay.Results.The proliferation of AGS cells was accelerated by coculturing withH. pylorifor 4 and 8 h, but was suppressed at 24 and 48 h. HSP70 expression was decreased in AGS cells infected byH. pylorifor 48 h. The proliferation in HSP70-silenced AGS cells was inhibited after coculturing withH. pylorifor 24 and 48 h compared with the control group.Conclusions.Coculture ofH. pylorialtered the proliferation of gastric epithelial cells and decreased HSP70 expression. HSP70 knockdown supplemented the inhibitory effect ofH. pylorion proliferation of epithelial cells. These results indicate that the effects ofH. pylorion the proliferation of gastric epithelial cells at least partially depend on the decreased expression of HSP70 induced by the bacterium.

scholarly journals TIFA Signaling in Gastric Epithelial Cells Initiates the cag Type 4 Secretion System-Dependent Innate Immune Response to Helicobacter pylori Infection

mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Alevtina Gall ◽  
Ryan G. Gaudet ◽  
Scott D. Gray-Owen ◽  
Nina R. Salama
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Secretion System ◽  
Innate Immune ◽  
Gastric Ulcers ◽  
Bacterial Clearance ◽  
Gastric Epithelial Cells ◽  
H Pylori

ABSTRACT Helicobacter pylori is a bacterial pathogen that colonizes the human stomach, causing inflammation which, in some cases, leads to gastric ulcers and cancer. The clinical outcome of infection depends on a complex interplay of bacterial, host genetic, and environmental factors. Although H. pylori is recognized by both the innate and adaptive immune systems, this rarely results in bacterial clearance. Gastric epithelial cells are the first line of defense against H. pylori and alert the immune system to bacterial presence. Cytosolic delivery of proinflammatory bacterial factors through the cag type 4 secretion system ( cag -T4SS) has long been appreciated as the major mechanism by which gastric epithelial cells detect H. pylori . Classically attributed to the peptidoglycan sensor NOD1, recent work has highlighted the role of NOD1-independent pathways in detecting H. pylori ; however, the bacterial and host factors involved have remained unknown. Here, we show that bacterially derived heptose-1,7-bisphosphate (HBP), a metabolic precursor in lipopolysaccharide (LPS) biosynthesis, is delivered to the host cytosol through the cag -T4SS, where it activates the host tumor necrosis factor receptor-associated factor (TRAF)-interacting protein with forkhead-associated domain (TIFA)-dependent cytosolic surveillance pathway. This response, which is independent of NOD1, drives robust NF-κB-dependent inflammation within hours of infection and precedes NOD1 activation. We also found that the CagA toxin contributes to the NF-κB-driven response subsequent to TIFA and NOD1 activation. Taken together, our results indicate that the sequential activation of TIFA, NOD1, and CagA delivery drives the initial inflammatory response in gastric epithelial cells, orchestrating the subsequent recruitment of immune cells and leading to chronic gastritis. IMPORTANCE H. pylori is a globally prevalent cause of gastric and duodenal ulcers and cancer. H. pylori antibiotic resistance is rapidly increasing, and a vaccine remains elusive. The earliest immune response to H. pylori is initiated by gastric epithelial cells and sets the stage for the subsequent immunopathogenesis. This study revealed that host TIFA and H. pylori -derived HBP are critical effectors of innate immune signaling that account for much of the inflammatory response to H. pylori in gastric epithelial cells. HBP is delivered to the host cell via the cag -T4SS at a time point that precedes activation of the previously described NOD1 and CagA inflammatory pathways. Manipulation of the TIFA-driven immune response in the host and/or targeting of ADP-heptose biosynthesis enzymes in H. pylori may therefore provide novel strategies that may be therapeutically harnessed to achieve bacterial clearance.

scholarly journals Unique susceptibility of Helicobacter pylori to simethicone emulsifiers in alimentary therapeutic agents.

1996 ◽  
Vol 40 (2) ◽  
pp. 500-502 ◽  
Author(s):  
A V Kane ◽  
A G Plaut
Keyword(s):  
Helicobacter Pylori ◽  
Therapeutic Agents ◽  
Gram Negative Bacteria ◽  
Gram Negative

Helicobacter pylori is killed in vitro by polyoxyethylene acyl esters and ethers similar to simethicone emulsifiers in therapeutic antifoams. The MBC of these compounds for Helicobacter pylori was less than 20 micrograms/ml, while other gram-negative bacteria were unaffected by much higher concentrations of up to 50 mg/ml.

scholarly journals Helicobacter pylori colonization and oral health in children

2017 ◽  
Vol 12 (2) ◽  
pp. 41-44
Author(s):  
Vasile Valeriu LUPU ◽  
◽  
Gabriela PĂDURARU ◽  
Anca ADAM ◽  
Ana-Maria DĂBULEANU ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Oral Health ◽  
Gastric Mucosa ◽  
Oral Cavity ◽  
Gold Standard ◽  
Dental Plaque ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Standard Triple Therapy ◽  
H Pylori

Helicobacter pylori (H. pylori) is a microaerophilic gram-negative bacterium infecting approximately one half of the world’s population. The oral cavity and dental plaque may be a reservoir for H. pylori infection. Diagnosis of H. pylori infection in children differs from that of adults. Although H. pylori has long been known to be detected in the oral cavity, the significance of such findings are controversial. Oral H. pylori may play an important role in re-infection of the gastric mucosa. The gold standard for eradicating H. pylori infection is standard triple therapy. The studies have shown promising results in the management of both oral and gastric H. pylori.

Sign in / Sign up

Export Citation Format

Share Document