scholarly journals comH, a Novel Gene Essential for Natural Transformation of Helicobacter pylori

2000 ◽  
Vol 182 (14) ◽  
pp. 3948-3954 ◽  
Author(s):  
Leonard C. Smeets ◽  
Jetta J. E. Bijlsma ◽  
Sacha Y. Boomkens ◽  
Christina M. J. E. Vandenbroucke-Grauls ◽  
Johannes G. Kusters
Keyword(s):  
Helicobacter Pylori ◽  
Natural Transformation ◽  
Bacterial Genome ◽  
Uptake System ◽  
Dna Uptake ◽  
Mutant Library ◽  
Chromosomal Dna ◽  
Orthologous Genes ◽  
Helicobacter Felis ◽  
H Pylori

ABSTRACT Helicobacter pylori is naturally competent for transformation, but the DNA uptake system of this bacterium is only partially characterized, and nothing is known about the regulation of competence in H. pylori. To identify other components involved in transformation or competence regulation in this species, we screened a mutant library for competence-deficient mutants. This resulted in the identification of a novel,Helicobacter-specific competence gene (comH) whose function is essential for transformation of H. pyloriwith chromosomal DNA fragments as well as with plasmids. Complementation of comH mutants in transcompletely restored competence. Unlike other transformation genes ofH. pylori, comH does not belong to a known family of orthologous genes. Moreover, no significant homologs ofcomH were identified in currently available databases of bacterial genome sequences. The comH gene codes for a protein with an N-terminal leader sequence and is present in both highly competent and less-efficient transforming H. pyloristrains. A comH homolog was found in Helicobacter acinonychis but not in Helicobacter felis andHelicobacter mustelae.

scholarly journals Serodiagnosis and Bacterial Genome of Helicobacter pylori Infection

Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 467
Author(s):  
Aina Ichihara ◽  
Hinako Ojima ◽  
Kazuyoshi Gotoh ◽  
Osamu Matsushita ◽  
Susumu Take ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibody Titer ◽  
Bacterial Genome ◽  
Serum Antibody ◽  
Gene Mutations ◽  
Bacterial Genomes ◽  
Western Blots ◽  
A Genome ◽  
Vaca Gene ◽  
H Pylori

The infection caused by Helicobacter pylori is associated with several diseases, including gastric cancer. Several methods for the diagnosis of H. pylori infection exist, including endoscopy, the urea breath test, and the fecal antigen test, which is the serum antibody titer test that is often used since it is a simple and highly sensitive test. In this context, this study aims to find the association between different antibody reactivities and the organization of bacterial genomes. Next-generation sequences were performed to determine the genome sequences of four strains of antigens with different reactivity. The search was performed on the common genes, with the homology analysis conducted using a genome ring and dot plot analysis. The two antigens of the highly reactive strains showed a high gene homology, and Western blots for CagA and VacA also showed high expression levels of proteins. In the poorly responsive antigen strains, it was found that the inversion occurred around the vacA gene in the genome. The structure of bacterial genomes might contribute to the poor reactivity exhibited by the antibodies of patients. In the future, an accurate serodiagnosis could be performed by using a strain with few gene mutations of the antigen used for the antibody titer test of H. pylori.

scholarly journals Protein-Protein Interactions among Helicobacter pylori Cag Proteins

2006 ◽  
Vol 188 (13) ◽  
pp. 4787-4800 ◽  
Author(s):  
Valerie J. Busler ◽  
Victor J. Torres ◽  
Mark S. McClain ◽  
Oscar Tirado ◽  
David B. Friedman ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Protein Interactions ◽  
Secretion System ◽  
Type Iv Secretion ◽  
Type Iv Secretion System ◽  
Protein Protein Interactions ◽  
Chromosomal Dna ◽  
2D Dige ◽  
Type Iv ◽  
H Pylori

ABSTRACT Many Helicobacter pylori isolates contain a 40-kb region of chromosomal DNA known as the cag pathogenicity island (PAI). The risk for development of gastric cancer or peptic ulcer disease is higher among humans infected with cag PAI-positive H. pylori strains than among those infected with cag PAI-negative strains. The cag PAI encodes a type IV secretion system that translocates CagA into gastric epithelial cells. To identify Cag proteins that are expressed by H. pylori during growth in vitro, we compared the proteomes of a wild-type H. pylori strain and an isogenic cag PAI deletion mutant using two-dimensional difference gel electrophoresis (2D-DIGE) in multiple pH ranges. Seven Cag proteins were identified by this approach. We then used a yeast two-hybrid system to detect potential protein-protein interactions among 14 Cag proteins. One heterotypic interaction (CagY/7 with CagX/8) and two homotypic interactions (involving H. pylori VirB11/ATPase and Cag5) were similar to interactions previously reported to occur among homologous components of the Agrobacterium tumefaciens type IV secretion system. Other interactions involved Cag proteins that do not have known homologues in other bacterial species. Biochemical analysis confirmed selected interactions involving five of the proteins that were identified by 2D-DIGE. Protein-protein interactions among Cag proteins are likely to have an important role in the assembly of the H. pylori type IV secretion apparatus.

scholarly journals Silencing of natural transformation by an RNA chaperone and a multitarget small RNA

2016 ◽  
Vol 113 (31) ◽  
pp. 8813-8818 ◽  
Author(s):  
Laetitia Attaiech ◽  
Aïda Boughammoura ◽  
Céline Brochier-Armanet ◽  
Omran Allatif ◽  
Flora Peillard-Fiorente ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Natural Transformation ◽  
Bacterial Species ◽  
Physiological State ◽  
Uptake System ◽  
Dna Uptake ◽  
Exogenous Dna ◽  
Major Mechanism ◽  
Transcriptional Gene Regulation ◽  
High Level

A highly conserved DNA uptake system allows many bacteria to actively import and integrate exogenous DNA. This process, called natural transformation, represents a major mechanism of horizontal gene transfer (HGT) involved in the acquisition of virulence and antibiotic resistance determinants. Despite evidence of HGT and the high level of conservation of the genes coding the DNA uptake system, most bacterial species appear non-transformable under laboratory conditions. In naturally transformable species, the DNA uptake system is only expressed when bacteria enter a physiological state called competence, which develops under specific conditions. Here, we investigated the mechanism that controls expression of the DNA uptake system in the human pathogenLegionella pneumophila. We found that a repressor of this system displays a conserved ProQ/FinO domain and interacts with a newly characterizedtrans-acting sRNA, RocR. Together, they target mRNAs of the genes coding the DNA uptake system to control natural transformation. This RNA-based silencing represents a previously unknown regulatory means to control this major mechanism of HGT. Importantly, these findings also show that chromosome-encoded ProQ/FinO domain-containing proteins can assisttrans-acting sRNAs and that this class of RNA chaperones could play key roles in post-transcriptional gene regulation throughout bacterial species.

cagA-Positive Helicobacter pylori Populations in China and The Netherlands Are Distinct

1998 ◽  
Vol 66 (5) ◽  
pp. 1822-1826 ◽  
Author(s):  
Arie van der Ende ◽  
Zhi-Jun Pan ◽  
Aldert Bart ◽  
René W. M. van der Hulst ◽  
Monique Feller ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
The Netherlands ◽  
Random Amplified Polymorphic Dna ◽  
Chromosomal Dna ◽  
High Confidence ◽  
Protein Levels ◽  
Group I ◽  
Rapd Pcr ◽  
H Pylori ◽  
Chinese Group

ABSTRACT The aim of this research was to study whether and to what extent Chinese cagA-positive Helicobacter pyloriisolates differ from those in The Netherlands. Analysis of random amplified polymorphic DNA (RAPD)-PCR-assessed DNA fingerprints of chromosomal DNA of 24 cagA-positive H. pylori isolates from Dutch (n = 12) and Chinese (n = 10) patients yielded the absence of clustering. Based on comparison of the sequence of a 243-nucleotide part ofcagA, the Dutch (group I) and Chinese (group II)H. pylori isolates formed two separate branches with high confidence limits in the phylogenetic tree. These two clusters were not observed when the sequence of a 240-bp part ofglmM was used in the comparison. The number of nonsynonymous substitutions was much higher in cagA than inglmM, indicating positive selection. The average levels of divergence of cagA at the nucleotide and protein levels between group I and II isolates were found to be high, 13.3 and 17.9%, respectively. Possibly, the pathogenicity island (PAI) that has been integrated into the chromosome of the ancestor of H. pylori now circulating in China contained a differentcagA than the PAI that has been integrated into the chromosome of the ancestor of H. pylori now circulating in The Netherlands. We conclude that in China and The Netherlands, two distinct cagA-positive H. pylori populations are circulating.

scholarly journals Identification of the periplasmic DNA receptor for natural transformation of Helicobacter pylori

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Prashant P. Damke ◽  
Anne Marie Di Guilmi ◽  
Paloma Fernández Varela ◽  
Christophe Velours ◽  
Stéphanie Marsin ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Natural Transformation ◽  
Bacterial Species ◽  
Dna Binding Protein ◽  
Gram Negative Bacteria ◽  
Membrane Channel ◽  
Inner Membrane ◽  
Double Stranded Dna ◽  
Periplasmic Domain ◽  
H Pylori

AbstractHorizontal gene transfer through natural transformation is a major driver of antibiotic resistance spreading in many pathogenic bacterial species. In the case of Gram-negative bacteria, and in particular of Helicobacter pylori, the mechanisms underlying the handling of the incoming DNA within the periplasm are poorly understood. Here we identify the protein ComH as the periplasmic receptor for the transforming DNA during natural transformation in H. pylori. ComH is a DNA-binding protein required for the import of DNA into the periplasm. Its C-terminal domain displays strong affinity for double-stranded DNA and is sufficient for the accumulation of DNA in the periplasm, but not for DNA internalisation into the cytoplasm. The N-terminal region of the protein allows the interaction of ComH with a periplasmic domain of the inner-membrane channel ComEC, which is known to mediate the translocation of DNA into the cytoplasm. Our results indicate that ComH is involved in the import of DNA into the periplasm and its delivery to the inner membrane translocator ComEC.

scholarly journals High-Level β-Lactam Resistance Associated with Acquired Multidrug Resistance in Helicobacter pylori

2003 ◽  
Vol 47 (7) ◽  
pp. 2169-2178 ◽  
Author(s):  
Dong H. Kwon ◽  
M. P. Dore ◽  
J. J. Kim ◽  
M. Kato ◽  
M. Lee ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Multidrug Resistance ◽  
Natural Transformation ◽  
Multidrug Resistant ◽  
Resistant Isolate ◽  
Terminal Portion ◽  
Nucleotide Substitutions ◽  
H Pylori ◽  
High Level ◽  
Level Resistance

ABSTRACT Four clinical Helicobacter pylori isolates with high-level resistance to β-lactams exhibited low- to moderate-level resistance to the structurally and functionally unrelated antibiotics ciprofloxacin, chloramphenicol, metronidazole, rifampin, and tetracycline. This pattern of multidrug resistance was transferable to susceptible H. pylori by natural transformation using naked genomic DNA from a clinical multidrug-resistant isolate. Acquisition of the multidrug resistance was also associated with a change in the genotype of the transformed multidrug-resistant H. pylori. DNA sequence analyses of the gene encoding penicillin binding protein 1A (PBP 1A) showed 36 nucleotide substitutions resulting in 10 amino acid changes in the C-terminal portion (the putative penicillin binding domain). Acquisition of β-lactam resistance was consistently associated with transfer of a mosaic block containing the C-terminal portion of PBP 1A. No changes of genes gyrA, rpoB, rrn16S, rdxA, and frxA, and nine other genes (ftsI, hcpA, llm, lytB, mreB, mreC, pbp2, pbp4, and rodA1) encoding putative PBPs or involved in cell wall synthesis were found among the transformed resistant H. pylori. Antibiotic accumulations of chloramphenicol, penicillin, and tetracycline were all significantly decreased in the natural and transformed resistant H. pylori compared to what was seen with susceptible H. pylori. Natural transformation also resulted in the outer membrane protein profiles of the transformed resistant H. pylori becoming similar to that of the clinical resistant H. pylori isolates. Overall, these results demonstrate that high-level β-lactam resistance associated with acquired multidrug resistance in clinical H. pylori is mediated by combination strategies including alterations of PBP 1A and decreased membrane permeability.

scholarly journals Evaluation of a Monoclonal Antibody-Based Test for Detection of Helicobacter pylori-Specific Antigen in Stool Samples from Mice

2004 ◽  
Vol 11 (4) ◽  
pp. 799-800 ◽  
Author(s):  
Julia Crone ◽  
Erin Symonds ◽  
Fiona Campbell ◽  
Ross Butler
Keyword(s):  
Monoclonal Antibody ◽  
Helicobacter Pylori ◽  
Monoclonal Antibodies ◽  
Sensitivity And Specificity ◽  
Specific Antigen ◽  
Noninvasive Technique ◽  
Helicobacter Felis ◽  
Stool Samples ◽  
H Pylori

ABSTRACT A test using monoclonal antibodies for detection of antigen in stool samples was compared with culture and histology for noninfected (n = 25), Helicobacter pylori-infected (n = 25), and Helicobacter felis-infected (n = 6) mice. Sensitivity and specificity were 96%. The monoclonal antibody-based test is therefore a noninvasive technique that is able to diagnose H. pylori infection in mice.

scholarly journals Helicobacter pylori DnaB helicase can bypass Escherichia coli DnaC function in vivo

2005 ◽  
Vol 389 (2) ◽  
pp. 541-548 ◽  
Author(s):  
Rajesh K. Soni ◽  
Parul Mehra ◽  
Gauranga Mukhopadhyay ◽  
Suman Kumar Dhar
Keyword(s):  
Escherichia Coli ◽  
Helicobacter Pylori ◽  
Temperature Sensitive ◽  
Chromosomal Dna ◽  
E Coli ◽  
Dnab Helicase ◽  
H Pylori

In Escherichia coli, DnaC is essential for loading DnaB helicase at oriC (the origin of chromosomal DNA replication). The question arises as to whether this model can be generalized to other species, since many eubacterial species fail to possess dnaC in their genomes. Previously, we have reported the characterization of HpDnaB (Helicobacter pylori DnaB) both in vitro and in vivo. Interestingly, H. pylori does not have a DnaC homologue. Using two different E. coli dnaC (EcdnaC) temperature-sensitive mutant strains, we report here the complementation of EcDnaC function by HpDnaB in vivo. These observations strongly suggest that HpDnaB can bypass EcDnaC activity in vivo.

scholarly journals Effect of Purified Lipopolysaccharides from Strains of Helicobacter pylori and Helicobacter felis on Acid Secretion in Mouse Gastric Glands In Vitro

2001 ◽  
Vol 69 (6) ◽  
pp. 3891-3896 ◽  
Author(s):  
Ireneusz T. Padol ◽  
Anthony P. Moran ◽  
Richard H. Hunt
Keyword(s):  
Helicobacter Pylori ◽  
Acid Secretion ◽  
Acid Output ◽  
Prostaglandin E ◽  
Gastric Glands ◽  
Helicobacter Felis ◽  
Bacterial Pathogenicity ◽  
Close Proximity ◽  
H Pylori

ABSTRACT As a bacterial product, Helicobacter pylorilipopolysaccharide (LPS) can originate in close proximity to parietal cells, but the role of this uniquely structured endotoxin on acid secretion has not been fully investigated and remains unclear. The purpose of this study was to test the direct effect of purified LPS (tested range, 0.1 to 100 μg/ml) from various strains of H. pylori and from one Helicobacter felis strain on histamine- and carbachol-stimulated acid secretion in vitro using mouse gastric glands and the accumulation of [14C]aminopyrine. In addition, we investigated whether H. pylori LPS can interfere with two native antisecretory substances, prostaglandin E2 (PGE2) and somatostatin, which may contribute to bacterial pathogenicity. Except for the LPS from H. pylori SS1 (Sydney strain), which gave a statistically significant increase in both histamine- and carbachol-stimulated acid output (38 and 24%, respectively; P < 0.05), no effect of the tested LPS was observed on acid secretion. H. pylori LPS purified from a patient isolate did not affect the potency or the efficacy of the inhibitory dose response curve to PGE2 or somatostatin. Bacterial interstrain variation in the direct stimulatory effect of Helicobacter-derived LPS on acid secretion was observed, which probably reflects the molecular structure of LPS and the potential to contribute to virulence. Importantly, the data showed that H. pylori LPS did not have any direct antisecretory properties. It can be speculated that the acid stimulatory properties of LPS from H. pylori SS1 may contribute to the gastric damage observed in the mouse model ofH. pylori infection.

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