To infect a susceptible host, the gastrointestinal pathogen Yersinia enterocolitica must survive passage through the acid environment of the stomach. In this study, we showed that Y. enterocolitica serotype O8 survives buffered acidic conditions as low as pH 1.5 for long periods of time provided urea is available. Acid tolerance required an unusual cytoplasmically located urease that was activa...

BACKGROUND Helicobacter pylori urease is a major target for immune responses among various bacterial components in H pylori infected patients. AIMS To analyse the relation between systemic and local humoral immune responses to H pylori urease and grades of chronic gastritis. PATIENTS Seventy five patients with chronic gastritis associated with H pylori infection were classified into three g...

We show that diffusion of single urease enzyme molecules increases in the presence of urea in a concentration-dependent manner and calculate the force responsible for this increase. Urease diffusion measured using fluorescence correlation spectroscopy increased by 16-28% over buffer controls at urea concentrations ranging from 0.001 to 1 M. This increase was significantly attenuated when urease...

The aim of the study was to evaluate the suitability of a modified one minute rapid urease test (one day rapid urease test) as a low cost H. pylori detection method. A sample of 205 patients clinically suspected of having H. pylori infection was tested. One day rapid urease test and histology based H. pylori tests (the gold standard) were performed on endoscopic antral biopsies. There were 6 tr...

Several 3-formylchromone derivatives were examined for their tumor cell-cytotoxic, anti-Helicobacter pylori, urease inhibitory and anti-HIV activity. Comparing their relative cytotoxicity against four human tumor cell lines and three normal human cells, tumor cell-specific cytotoxicity was detected in some 3-formylchromone derivatives. There was no clear-cut relationship between the cytotoxicit...

color from ammonia was produced by an additional 5 min of incubation at 37 C. All strains of Proteus, except those of P. inconstans, generated detectable amounts of ammonia (Table 1). None of the Escherichia organisms was urease-positive. These findings were identical with those yielded by the urease technique of Stuart et al. The sensitivity of the Berthelot color reaction permits detection of...

To produce bispecific antibodies (BiAbs) for enzyme immunoassay (EIA) to replace antibody-enzyme conjugates, we developed a panel of 8-azaguanine/ouabain-resistant anti-urease variant hybridoma cell lines for use in hybridoma-hybridoma fusions. These variants represent mouse immunoglobulin subclasses IgM, IgG1, IgG2a, and IgG2b and have growth rates equal to those of the parental hybridomas. We...

Urease activity was determined in soil contaminated with four polycyclic aromatic hydrocarbons (PAHs): naphthalene, phenanthrene, anthracene, and pyrene in the amount of 0, 1,000, 2,000, and 4,000 mg·kg DM soil. Organic materials – cellulose, sucrose, and compost – were applied to the samples in the amount of 0 and 9 g·kg DM soil. The experiment was carried out in a laboratory, and soil samples...

Mutation at either of two genetic loci (Eu2 or Eu3) in soybean (Glycine max [L.] Merr.) results in a pleiotropic elimination of the activity of both major urease isozymes. Surprisingly, the phenotype of a phylloplane bacterium, Methylobacterium mesophilicum, living on the leaves of eu2/eu2 or eu3-el/eu3-el mutants is also affected by these plant mutations. The bacteria isolated from leaves of t...

Characterization of a series of urease-negative transposon mutations of Actinobacillus pleuropneumoniae revealed that many of the mutants had insertions 2 to 4 kbp upstream of the urease gene cluster. A 5-kbp upstream region of DNA was sequenced and found to contain six open reading frames (ORFs) transcribed in the same orientation as the urease genes. As well, a partial ORF, apuR, 202 bp upstr...