Since the discovery of Helicobacter pylori, the urease activity of this bacterial pathogen has been identified as the key factor in infection and acid acclimation in the human stomach. Ureolytic activity plays a key role in the pathogenesis of several bacteria, and urease has also been described as an emerging pathogenic factor during fungal infection. However, urease produced by the oral bacte...

BACKGROUND Urease B is an important virulence factor that is required for Helicobacter pylori to colonise the gastric mucosa. Mouse monoclonal antibodies (mAbs) that inhibit urease B enzymatic activity will be useful as vaccines for the prevention and treatment of H. pylori infection. Here, we produced murine mAbs against urease B that neutralize the enzyme's activity. We mapped their epitopes ...

The role of microbial urease in calcite precipitation was studied utilizing a recombinant Escherichia coli HB101 containing a plasmid, pBU11, that encodes Bacillus pasteurii urease. The calcite precipitation by E. coli HB101 (pBU11) was significant although its precipitation level was not as high as that by B. pasteurii. Addition of low concentrations (5-100 microM) of nickel, the cofactor of u...

SoilScience • Volume 175, Number 11, November 2010 Urease is one of the most thoroughly studied soil enzymes because it greatly influences the fate and performance of a widely used fertilizer (urea) (Bremner and Mulvaney, 1978; Ma et al., 1999; Tate, 2002). Urea was reported to be taken up by microorganisms, such as Corynebacterium glutamicum and Paxillus involutus (Jahns and Kaltwasser, 1989; ...

The role in virulence of Actinobacillus pleuropneumoniae urease activity was investigated. A urease-negative mutant was isolated following transposon mutagenesis with a mini-Tn10 derivative. Both the parent strain and the urease-negative mutant exhibited identical LD50 values in a murine infection model. Pig challenge confirmed that the urease-negative mutant was fully virulent, since experimen...

The role of urease in Helicobacter pylori adherence to and internalization by Kato III cells was investigated. Kato III cells were incubated with wild-type strains (N6 or P1), with isogenic mutants lacking urease (N6ureB::TnKm or P1ureA::TnMax5) or producing the inactive apoprotein (N6ureG::TnKm), and with urease-positive clones recovered after complementation of N6ureB::TnKm with ureAB. Bacter...

Urease represents a critical virulence factor for some bacterial species through its alkalizing effect, which helps neutralize the acidic microenvironment of the pathogen. In addition, urease serves as a nitrogen source provider for bacterial growth. Pathogenic mycobacteria express a functional urease, but its role during infection has yet to be characterized. In this study, we constructed a ur...

The identity of the enzyme urease with the octahedral globulin crystals isolated by the senior author from the jack bean in 1926 (1) has been challenged by Waldschmidt-Leitz and Steigerwaldt (2). These investigators published a paper in which they claimed that crystalline urease is not inactivated at pH 7.0 by incubation with trypsin or papain, while the protein component of the urease undergoe...

Ureaplasmas killed mice within 5 min after intravenous injection. The 50% lethal dose of whole ureaplasmal organisms was 32 micrograms per mouse, a value also found for crystalline jackbean urease. The reaction was specific to urease, since protection was afforded by intraperitoneal injection of 200 micrograms of flurofamide, a potent urease inhibitor. The finding that a similar lethal effect w...