Haemolytic activity ofCampylobacter pylori

Wetherall, B L; Johnson, Alan M.

doi:10.1007/bf01963756

Cited by 18 publications

(13 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The factor(s) that mediate hemolysis of H. pylori have not been characterized in detail [59]. The production of hemolysins might be a tool for pathogenic bacteria to survive in the host [7,39].…”

Section: Discussionmentioning

confidence: 99%

“…It is known from earlier studies that H. pylori expresses hemolytic activity that can be detected by growth on blood agar [1,59]. Moreover, H. pylori DNA fragments which code for hemolytic properties were identified and isolated by heterologous expression of hemolytic determinants in E. coli strains carrying plasmidbased genomic libraries of H. pylori grown on blood agar plates [18].…”

Section: Introductionmentioning

confidence: 99%

“…It is considered to be primarily responsible for chronic gastritis and peptic ulcer disease [36], and one of the main risk factors for MALT-lymphoma and gastric cancer [2]. The pathogen is well adapted to its specific ecological niche, and the colonization of the gastric mucosa depends on the production of several virulence factors, such as urease [20,57], vacuolating toxin [15,45,55], flagellin [19,21,28], several adherence factors [8,9], and phospholipases [16,17,59].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hemolytic properties and riboflavin synthesis of Helicobacter pylori: cloning and functional characterization of the rib A gene encoding GTP-cyclohydrolase II that confers hemolytic activity to Escherichia coli

Bereswill

Fassbinder

Völzing

et al. 1998

Medical Microbiology and Immunology

View full text Add to dashboard Cite

Various strains of Helicobacter pylori were able to lyse erythrocytes from sheep, horse, and human when grown on blood agar. The hemolysis did not depend on the production of the vacuolating cytotoxin VacA as demonstrated by the hemolytic behavior of an isogenic vacA-negative mutant strain. The hemolytic activity could be detected in cell-free supernatants and was not regulated by iron. To isolate genes coding for proteins involved in the destruction of erythrocytes, a plasmid-based DNA library was screened for expression of lytic activity on blood agar. This approach revealed that the H. pylori ribA gene confers hemolytic properties to Escherichia coli. The ribA gene encodes the enzyme GTP-cyclohydrolase II [EC 3.5.4.25] that catalyzes the initial step in the synthesis of riboflavin. The predicted amino acid sequence of the H. pylori RibA protein showed a high degree of similarity to equivalent enzymes from microorganisms and from plants. The single gene on a plasmid restored riboflavin synthesis in a ribA mutant of E. coli and induced hemolytic activity. Furthermore, ribA overexpression was associated with the production of a fluorescent yellow molecule that was not identical with riboflavin. Hemolysis was also seen for the ribA gene from E. coli, indicating that this feature was not specific for the H. pylori gene. The presence of ribA in various H. pylori strains was confirmed by Southern blot hybridization and by polymerase chain reaction with specific primers. This analysis revealed that microdiversity exists within the DNA region upstream from ribA, which was further confirmed by nucleotide sequence analysis.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hemolytic properties and riboflavin synthesis of Helicobacter pylori: cloning and functional characterization of the rib A gene encoding GTP-cyclohydrolase II that confers hemolytic activity to Escherichia coli

Bereswill

Fassbinder

Völzing

et al. 1998

Medical Microbiology and Immunology

View full text Add to dashboard Cite

show abstract

“…This is consistent with either a serum factor(s) stimulating catalase activity and/or the presence of haem-containing proteins, released from erythrocytes by the action of H . pylori (Wetherall & Johnson, 1989), suppressing the synthesis of catalase. Suppression of synthesis of porphyrins by haem groups has been demonstrated in mature mammalian cells; and in rodents, liver catalase activity increases subsequent to serum injection (Weil-Malherbe & Schade, 1948 ;Woods, 1974).…”

mentioning

confidence: 99%

Helicobacter pylori catalase

1991

View full text Add to dashboard Cite

Helicobacter pylori is the major aetiological agent of gastroduodenitis in humans. Due to the potential importance of catalase in the growth and survival of Helicobacter pylori on the surface of inflamed mucosae, we have characterized catalase from H. pyfori as a prelude to further studies on the function of the enzyme in uiuo. The catalase activity of H. pylori was significantly affected by the presence of blood, serum or erythrocytes in the growth medium: the greatest activity was expressed when the bacterium was grown on medium containing serum. H.pyloricatalase is a tetramer with a subunit M, of 50000. The enzyme had a PI of 94-9.3, was active over a broad pH range and was stable at 56 OC. It was non-competitively inhibited by sodium azide, and had no detectable

show abstract

“…Lipids and proteins in epithelium are peroxidized, and the cellular structure and function were damaged, and finally the epithelial barrier was destroyed. Hemolysin: H. pylori can secret hemolysin that has cytotoxic effects, induces inflammatory reaction, and results in the injury of epithelial barrier (Wetherall et al, 1989). In addition, H.pylori inhibits the expression of constitutive nitric oxide (cNOS) and enhances the expression of inducible NOS (iNOS) that may lead to the overproduction of NO and the excessive generation of toxic radical peroxynitrate the is involved in the gastric cell inflammatory response and cellular damage (Brzozowski et al, 2006).…”

mentioning

confidence: 99%