Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sensitive immunoassays are essential for establishing the efficacy of recombinant vaccines to hepatitis B virus (HBV). These experimental vaccines include the PreS2 and S domains of the HBV envelope protein. To facilitate measurement of antibody against HBV PreS2, we employed the immuno-ligand assay with silicon sensor-based detection. Labeling of immune reagents with the haptens biotin and fluorescein allows adaptation to the immunofiltration light addressable potentiometric sensor (LAPS) system. A biotinylated monoclonal anti-PreS2 antibody and anti-PreS2 in clinical serum samples competitively bind in liquid phase to a fluorescein labeled PreS2 + S antigen. Streptavidin mediates the immobilization on biotinylated nitrocellulose membranes. Fluorescein mediates binding of an anti-fluorescein urease conjugate to the immune complex. Urease serves as the signal-generating component which subsequently is measured in the LAPS reader. In comparison to a competitive RIA, the immuno-ligand assay demonstrated a four-fold improved sensitivity using a smaller sample volume. The higher sensitivity resulted in earlier detection of seroconversion during a clinical vaccine study.
J Immunol Methods 1991 Dec 15
PMID:Detection of antibody to the PreS2 sequence of the hepatitis B virus envelope protein using an immuno-ligand assay with a silicon sensor detection system. 176 51

Helicobacter pylori (HP) is an important etiological factor in chronic gastritis and duodenal ulceration. Demonstration of HP by means of culture and histological examination is relatively time-consuming. The object of this investigation was to assess the validity of two rapidly read chemical tests: the buffered urease reagent (BR) and the unbuffered urease reagent (UBR) in demonstration of HP among patients referred for gastroscopy on account of upper abdominal dyspepsia. In 230 sets of biopsies investigated for HP by culture and histology, the following results were obtained by reading of the BR test three hours later at room temperature: Nosographic sensitivity 0.54, nosographic specificity 0.97, PVpos 0.93 and PVneg 0.71. In another material consisting of 57 sets of biopsies, both BR and UBR were performed. Reading of UBR after 15 minutes yielded the following results: Nosographic sensitivity 0.56, nosographic specificity 1.00, PVpos 1.00 and PVneg 0.61. It is concluded that positive results of the urease tests indicate the presence of HP. If the urease tests are negative, supplementary culture and/or histological examination for HP should be performed. UBR is preferable rather than BR.
Ugeskr Laeger 1991 Dec 30
PMID:[Urease test for rapid demonstration of Helicobacter pylori in biopsies from the pyloric antrum]. 178 Oct 60

Three turkey growth experiments were conducted to evaluate the effect of overcooked soybean meal (SBM) on BW gain and gain:feed ratio (FE). On two occasions soybean meals were custom prepared by changing the temperature and the retention time (RT) of the desolventizer-toaster unit at a commercial soybean processing plant. Three different meals were produced for each occasion mainly by altering RT from normal to approximately 1.35 and 2.43 times normal operating conditions (designated SBM1 to 3 on the first occasion and SBM4 to 6 on the second occasion). For SBM1 to 6, urease activities were .06, .00, .20, .01 and .00 delta pH, protein solubilities in .1 M borate at 40 C were 44, 45, 16, 44, 32, and 24%, and protein solubilities in .2% KOH were 86, 84, 76, 90, 85, and 85%, respectively. In two sequential long-term experiments, SBM1 to 3 were fed to turkeys from 0 to 8 wk, then a control (normal processing conditions, SBMF), was fed to the all treatment groups from 8 to 12 wk of age. The SBM4 to 6 were fed from 12 to 18 wk of age after rerandomizing treatment allocation of replicate pens. In the first trial, poults fed SBM3 showed significantly reduced BW gain from 3 wk on and a lower FE shown at 9 wk. No difference in BW gain and FE was observed in the trial from 12 to 18 wk. In a 15-day, short-term experiment starting with 3-day-old poults and feeding diets containing SBM2 to 6, BW gain and FE did not differ among treatment groups. It is concluded that SBM did not show a detrimental effect on turkey growth until it was overcooked by 2.4 times the normal conditions. The usual operating conditions in a commercial processing plant are well within the range for producing adequate SBM for poultry feed.
Poult Sci 1991 Dec
PMID:Effect of overcooked soybean meal on turkey performance. 178 73

The survival of Staphylococcus epidermidis strain KH 11 in the presence of synthetic high molecular polyurethanes was prolonged in comparison to control experiments performed in the absence of any nutrients. Investigations of the bacteria after contact with the polymers revealed changes in their surface properties and metabolism, in particular a marked induction of urease activity. ESCA (Electron Spectroscopy for Chemical Analysis) measurements detected a decrease in elementary nitrogen in the polyurethane surfaces after incubation with the bacteria. The alterations observed indicate an urease-induced degradation of synthetic polymers by Staphylococcus epidermidis KH 11.
Zentralbl Bakteriol 1991 Dec
PMID:Evidence for degradation of synthetic polyurethanes by Staphylococcus epidermidis. 178 99

Trace levels of urethane, a cancer causing chemical, were detected in many kinds of wine, sherry, whisky, brandy and sake. Urethane formation from urea and ethanol in sake can be prevented by the treatment of acid urease, which is produced by Lactobacillus fermentum, but urethane, once formed, is very difficult to decompose. In order to keep the safety of alcoholic beverages, enzymatic removal of urethane has become an urgent problem. We found that Bacillus licheniformis sp., isolated from mouse gastrointestine, decomposed urethane to ethanol and ammonia. The enzyme showed higher urethanase activity at an acidic condition than at a neutral condition, and was resistant against ethyl alcohol of high concentrations. However, the enzyme had a low affinity to urethane for the industrial removal of the compound from alcoholic beverages.
Chem Pharm Bull (Tokyo) 1991 Dec
PMID:Urethanase of Bacillus licheniformis sp. isolated from mouse gastrointestine. 181 24

Nephrolithiasis is a heterogeneous disorder, with varying chemical composition and pathophysiologic background. Although kidney stones are generally composed of calcium oxalate or calcium phosphate, they may also consist of uric acid, magnesium-ammonium phosphate, or cystine. Stones develop from a wide variety of metabolic or environmental disturbances, including varying forms of hypercalciuria, hypocitraturia, undue urinary acidity, hyperuricosuria, hyperoxaluria, infection with urease-producing organisms, and cystinuria. The cause of stone formation may be ascertained in most patients using the reliable diagnostic protocols that are available for the identification of these disturbances. Effective medical treatments, capable of correcting underlying derangements, have been formulated. They include sodium cellulose phosphate, thiazide, and orthophosphate for hypercalciuric nephrolithiasis; potassium citrate for hypocitraturic calcium nephrolithiasis; acetohydroxamic acid for infection stones; and D-penicillamine and alpha-mercaptopropionylglycine for cystinuria. Using these treatments, new stone formation can now be prevented in most patients.
Am J Kidney Dis 1991 Dec
PMID:Etiology and treatment of urolithiasis. 196 46

A positive, genetic selection against the activity of the nitrogen regulatory (NTR) system was used to isolate insertion mutations affecting nitrogen regulation in Klebsiella aerogenes. Two classes of mutation were obtained: those affecting the NTR system itself and leading to the loss of almost all nitrogen regulation, and those affecting the nac locus and leading to a loss of nitrogen regulation of a family of nitrogen-regulated enzymes. The set of these nac-dependent enzymes included histidase, glutamate dehydrogenase, glutamate synthase, proline oxidase, and urease. The enzymes shown to be nac independent included glutamine synthetase, asparaginase, tryptophan permease, nitrate reductase, the product of the nifLA operon, and perhaps nitrite reductase. The expression of the nac gene was itself highly nitrogen regulated, and this regulation was mediated by the NTR system. The loss of nitrogen regulation was found in each of the four insertion mutants studied, showing that loss of nitrogen regulation resulted from the absence of nac function rather than from an altered form of the nac gene product. Thus we propose two classes of nitrogen-regulated operons: in class I, the NTR system directly activates expression of the operon; in class II, the NTR system activates nac expression and the product(s) of the nac locus activates expression of the operon.
J Bacteriol 1990 Dec
PMID:Role of the nac gene product in the nitrogen regulation of some NTR-regulated operons of Klebsiella aerogenes. 197 23

Two-hundred and ten consecutive patients undergoing routine gastroscopy were additionally investigated for evidence of Campylobacter pylori (C.p.). 106 patients were positive in one or more tests: 99.1% using a rapid urease detecting test (CLO-test), 80.2% histology, 78.3% cytology and 60% culture. We found no difference between the CLO-test results from biopsies taken from different parts of the stomach in individual patients. C.p. was found in 100% of patients with significant chronic antral gastritis, 67.7% with gastric ulcers, 65% with duodenal ulcers and in 12.1% of normal individuals. The C.p. infection was apparently eliminated in 50% of cases treated with bismuth subsalicylate (BSS) for four weeks. The combination of BSS with amoxicillin, tinidazole or an H2-receptor antagonist offered no advantage over BSS alone. Treatment with BSS led to improvement in symptoms and histological findings including healing of ulcers in patients with or without persistent C.p. infection. The recurrence of C.p. infection after apparently successful treatment was, however, 75% in 4 weeks. In conclusion, C.p. infection correlates strongly with the presence of chronic gastritis, and significantly with gastric and duodenal ulceration. The best diagnostic approach is the combination of a rapid urease detecting test and histology. C.p. infection is of long duration and difficult to eliminate. The most effective treatment for C.p. infection remains BSS as single agent.
Hepatogastroenterology 1990 Dec
PMID:Epidemiology and treatment of gastric Campylobacter pylori infection: more questions than answers. 198 7

An unusual campylobacter strain, a urease positive thermophilic variant of Campylobacter lari, was isolated from the urine of a patient with urinary tract infection who was hospitalized because of cirrhosis and haemorrhage. The strain was isolated from urine specimens on three separate occasions. A significant serological response to the organism was also detected. This is the first documented case of extra-intestinal infection due to this group of organisms.
Eur J Clin Microbiol Infect Dis 1990 Dec
PMID:Isolation of a urease positive thermophilic variant of Campylobacter lari from a patient with urinary tract infection. 207 1

These studies are an attempt to gain better insight into the pharmacophore requirements of urease. On the basis of published information on this enzyme (EXAFS, amino acid sequence, essential groups at the active site) a hypothetical nickel-tripeptide complex, as preliminary substitute for the urease active site was modeled using computer-aided molecular modeling techniques. The results suggest two alternative docking modes of urea and reaction intermediates, corresponding to two different reaction mechanisms. Both binding modes are compatible with the docking of known potent inhibitors such as selected hydroxamic acids and phosphorodiamides. The results can be used to help in the design of new potential inhibitors of urease.
J Comput Aided Mol Des 1990 Dec
PMID:Molecular modeling studies on the urease active site and the enzyme-catalyzed urea hydrolysis. 209 81


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