The urease enzymes of Campylobacter pylori and a related bacterium

Ferrero, Richard L.; Hazell, Stuart L.; Lee, A.

doi:10.1099/00222615-27-1-33

Cited by 75 publications

(42 citation statements)

References 29 publications

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“…The overall metabolism of H. pylori remains poorly understood although major studies on the virulence and pathogenic effects of bacterial enzymes have been carried out (Ferrero et al, 1988;Hazell et al, 1991;Hazell, 1992). The absence of fermentative pathways for saccharides was reported at the time of the discovery of the bacterium (Marshall & Warren, 1984) and confirmed later in different investigations (McNulty & Dent, 1987).…”

Section: Introductionmentioning

confidence: 99%

Glucose utilization and lactate production by Helicobacter pylori

Mendz

Hazell

Burns

1993

Journal of General Microbiology

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~ ~~The transport and incorporation of D-glucose into the human pathogen Helicobacter pyfori was investigated employing radioactive tracer analysis and 'H and 13C nuclear magnetic resonance spectroscopy. The bacterium was found to utilize D-glucose contrary to the accepted view that it cannot catabolize carbohydrates. Under the experimental conditions employed, the rate of transport of ('4C]glucose was 3.24 mmol min-' (g protein)-', and the rate of incorporation into the cellular mass was 1-06 pmol h-' (g protein)-'. The utilization of ('3C]glucose showed biphasic characteristics with a slower initial period followed by a phase with a rate of utilization at least an order of magnitude faster, The apparent rates of decline of glucose levels during both phases varied between strains and depended on the growth conditions of the bacteria prior to harvesting. The main product of glucose catabolism was identified as lactate. These findings provide new perspectives into the physiology of H. pylori and have implications for the active search to develop appropriate therapies for the micro-organism.

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Section: Introductionmentioning

confidence: 99%

Glucose utilization and lactate production by Helicobacter pylori

Mendz

Hazell

Burns

1993

Journal of General Microbiology

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“…H. pylon is now recognized as the etiologic agent of antral chronic gastritis (2) and is a probable contributor to the pathogenesis of peptic ulcer disease (2). This bacterium is characterized by the production of a potent urease (7,22) which has been described as a common trait of all bacteria belonging to the Helicobacter genus.…”

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Expression of Helicobacter pylori urease genes in Escherichia coli grown under nitrogen-limiting conditions

1992

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Helicobacter pylori produces a potent urease that is believed to play a role in the pathogenesis of gastroduodenal diseases. Four genes (ureA, ureB, ureC, and ureD) were previousl shown to be able to achieve a urease-positive phenotype when introduced into Campylobacter jejuni, whereas Escherichia coli cells harboring these genes did not express urease activity (A. Labigne, V. Cussac, and P. Courcoux, J. Bacteriol. 173:1920-1931). Results that demonstrate that H. pylori urease genes could be expressed in E. coli are presented in this article. This expression was found to be dependent on the presence of accessory urease genes hitherto undescribed. Subcloning of the recombinant cosmid pILL585, followed by restriction analyses, resulted in the cloning of an 11.2-kb fragment (pILL753) which allowed the detection of urease activity (0.83 + 0.39 ,umol of urea hydrolyzed per min/mg of protein) in E. coli cells grown under nitrogen-limiting conditions. Transposon mutagenesis of pILL753 with mini-Tn3-Km permitted the identification of a 3.3-kb DNA region that, in addition to the 4.2-kb region previously identified, was essential for urease activity in E.coli. Sequencing of the 3.3-kb DNA fragment revealed the presence of five open reading frames encoding polypeptides with predicted molecular weights of 20,701 (UreE), 28,530 (UreF), 21,744 (UreG), 29,650 (UreHl), and 19,819 (Urel). Of the nine urease genes identified, ureA, ureB, ureF, ureG, and ureH were shown to be required for urease expression in E. coli, as mutations in each of these genes led to negative phenotypes. The ureC, ureD, and ureI genes are not essential for urease expression in E. coil, although they belong to the urease gene cluster. The predicted UreE and UreG polypeptides exhibit some degree of similarity with the respective polypeptides encoded by the accessory genes of the KiebsieUla aerogenes urease operon (33 and 92% similarity, respectively, taking into account conservative amino acid changes),. whereas this homology was restricted to a

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“…The urease of H. pylori is an important characteristic for rapid detection of this bacterium (11,16,(26)(27)(28)35), and moreover, urease has been implicated as an important virulence factor of this organism (32). Urease is produced in large quantities by strains associated with infection, and antibodies to urease have been detected in sera from infected individuals (9). H. pylori urease is similar to that of many bacterial species in that it is a multimeric, high-molecularweight, nickel-containing enzyme which hydrolyzes urea to form carbon dioxide and ammonia (7,13,14).…”

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Macromolecular structure and aggregation states of Helicobacter pylori urease

et al. 1991

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Urease purified from Helicobacter pylori by differential ultracentrifugation and fast pressure liquid chromatography was composed of subunits with apparent molecular weights (MrS) of 66,000 and 30,000. Electron microscopy of this purified material demonstrated that it formed disc-shaped macromolecular aggregates that were approximately 13 nm in diameter and 3 nm thick. Images of both negatively stained and shadowed preparations indicated that the discs tended to stack to form pairs and then these pairs further aggregated to form four-disc stacks. This stacking of subunits explains the heterogeneity observed previously in the molecular weight of urease preparations. In some negatively stained preparations there were also some smaller (approximately 8-nm-diameter) annular units present, which may represent individual urease units or possibly an aggregate of one of the two subunits from which urease is constructed.

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The urease enzymes of Campylobacter pylori and a related bacterium

Cited by 75 publications

References 29 publications

Glucose utilization and lactate production by Helicobacter pylori

Glucose utilization and lactate production by Helicobacter pylori

Expression of Helicobacter pylori urease genes in Escherichia coli grown under nitrogen-limiting conditions

Macromolecular structure and aggregation states of Helicobacter pylori urease

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