The enzymatic activity of Helicobacter pylori's urease neutralises stomach acidity, thereby promoting infection by this pathogen. Urease protein has also been found to interact with host cells in vitro, although this property's possible functional importance has not been studied in vivo. To test for a role of the urease surface in the host/pathogen interaction, surface exposed loops that displa...

Importance of urease activity on pathogenic differences among Brucella species was evaluated. In cell-free extracts, the B. suis urease showed 12 times greater specific activity than the B. melitensis urease. When Fisher-344 rats were inoculated intraperitoneally (IP), at 1 week post-inoculation (PI), B. melitensis wild type 16 M was recovered from spleens and livers in greater numbers than B. ...

Urease was purified 800-fold and partially characterized from Proteus mirabilis, the predominant microorganism associated with urinary stones. Boric acid is a rapid reversible competitive inhibitor of urease. The pH-dependence of inhibition exhibited pKa values of 6.25 and 9.3, where the latter value is probably due to the inherent pKa of boric acid. Three boronic acids also were shown to inhib...

Title of Document: REGULATION OF ESTUARINE PHYTOPLANKTON AND BACTERIAL UREA UPTAKE AND UREASE ACTIVITY BY ENVIRONMENTAL FACTORS Caroline Miller Solomon, Ph.D., 2006 Directed By: Professor Patricia M. Glibert Marine Estuarine Environmental Science The regulation by environmental factors of two enzymes involved with urea utilization – urea transport and urease – in estuarine phytoplankton and bac...

BACKGROUND/AIMS The influence of different media on the validity of the rapid urease test, including accuracy, reaction time and cost-effectiveness is evaluated. METHODOLOGY Biopsies were obtained from the antral and body mucosa of 100 KMUH patients (51 men, 49 women; mean age: 54.0 years, range: 21-79 years old) undergoing gastroendoscopy due to dyspepsia. None of the patients had received a...

We examined the effects of urease and hydrogenase assembly gene deletions on NikR activation in H. pylori strains 26695 and G27. The loss of any component of urease assembly increased NikR activity under Ni2+-limiting conditions, as measured by reduced transcript levels and 63Ni accumulation. Additionally, SlyD functioned in urease assembly in strain 26695.

CONTEXT The correct diagnosis and effective treatment of Helicobacter pylori gastric infection are essential in controlling this infection. OBJECTIVE To compare the diagnostic value of three tests based in endoscopic gastric biopsies histopathological evaluation with hematoxylin-eosin (H-E) staining, urease rapid test and microbiological culture for detecting Helicobacter pylori active infect...

Early studies of a ureB mutant derivative of Helicobacter pylori had suggested that urease is needed for motility and that urease action helps energize flagellar rotation. Here we report experiments showing that motility is unaffected by deletion of ureA and ureB (urease genes) or by inactivation of ureB alone, especially if H. pylori strains used as recipients for transformation with mutant al...

Helicobacter mustelae, a gastric pathogen of ferrets, synthesizes a distinct iron-dependent urease in addition to its archetypical nickel-containing enzyme. The iron-urease is oxygen-labile, with the inactive protein exhibiting a methemerythrin-like electronic spectrum. Significantly, incubation of the oxidized protein with dithionite under anaerobic conditions leads to restoration of activity ...