Urea metabolism was studied with nitrogen-starved cells of Chlorella vulgaris Beijerinck var. viridis (Chodat), a green alga which apparently lacks urease. Incorporation of radioactivity from urea-(14)C into the alcohol-soluble fraction was virtually eliminated in cell suspensions flushed with 10% CO(2) in air. This same result was obtained when expected acceptors of urea carbon were replenishe...

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...

When urea is added to Ureaplasma urealyticum, it is hydrolysed internally by a cytosolic urease. Under our measuring conditions, and at an external pH of 6.0, urea hydrolysis caused an ammonia chemical potential equivalent to almost 80 mV and, simultaneously, an increase in proton electrochemical potential (delta p) of about 24 mV with resultant de novo ATP synthesis. Inhibition of the urease w...

Test meals are invariably used in the 13C-urea breath test (UBT) but their effect on the intragastric distribution and gastric residence time of urea given in the test is unknown. The site of Helicobacter pylori urease measured in the test is unknown and whether the test measures total or regional gastric urease is uncertain. This study reports the results of paired UBTs with simultaneous gastr...

Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen with a low infectious dose that colonizes the colon in humans and can cause severe clinical manifestations such as hemolytic-uremic syndrome. The urease enzyme, encoded in the STEC chromosome, has been demonstrated to act as a virulence factor in other bacterial pathogens. The NH(3) produced as urease hydrolyzes urea can aid...

To study the cytotoxic effect of Helicobacter pylori on the gastric P3cosa, gastric glands harvested from guinea pigs were incubated with clinical isolates of H. pylori. H. pylori alone (H group), urea alone (U group), H. pylori plus urea (HU group), and H. pylori plus urea and the urease inhibitor acetohydroxamic acid (HUA group) were incubated with isolated gastric glands. The controls were i...

Urease was covalently immobilized on the magnetic particles without and with polymer between urease particle. The insertion enhanced conversion from urea to bicarbonate. ureases were microparticles through covalent bonds. 150 μL of stock solution 3 μm diameter washed three times 20 mM MES rubbing at pH 6.0. results this study seem be useful in designing a reactor for recycling wastewater genera...

Helicobacter hepaticus causes disease in the liver and lower intestinal tract of mice. It is strongly urease positive, although it does not live in an acidic environment. The H. hepaticus urease gene cluster was expressed in Escherichia coli with and without coexpression of the Helicobacter pylori nickel transporter NixA. As for H. pylori, it was difficult to obtain enzymatic activity from reco...

We studied urea decomposition in depth profiles at stations in the Southern California Bight. Urea decomposition was measured by adding I4C urea as a tracer. In situ urea concentration was measured by the urease method; we, therefore, studied the decomposition of only the urease-sensitive fraction of the urea pool. In the mesopelagic zone the decomposition of urea, which was mainly due to the b...