نتایج جستجو برای: urease activity

تعداد نتایج: 1137208  

2013
Aneta Lipińska Jan Kucharski Jadwiga Wyszkowska

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...

Journal: :Infection and immunity 2000
D R Scott E A Marcus D L Weeks A Lee K Melchers G Sachs

ureI encodes an integral cytoplasmic membrane protein. It is present in the urease gene cluster of Helicobacter pylori and is essential for infection and acid survival, but its role is unknown. To determine the function of UreI protein, we produced H. pylori ureI deletion mutants and measured the pH dependence of urease activity of intact and lysed bacteria and the effect of urea on the membran...

Journal: :Molecules 2016
Yasmeen Gull Nasir Rasool Mnaza Noreen Ataf Ali Altaf Syed Ghulam Musharraf Muhammad Zubair Faiz-Ul-Hassan Nasim Asma Yaqoob Vincenzo DeFeo Muhammad Zia-Ul-Haq

A new series of N-(6-arylbenzo[d]thiazol-2-yl)acetamides were synthesized by C-C coupling methodology in the presence of Pd(0) using various aryl boronic pinacol ester/acids. The newly synthesized compounds were evaluated for various biological activities like antioxidant, haemolytic, antibacterial and urease inhibition. In bioassays these compounds were found to have moderate to good activitie...

2001
H. M. El-Shora

In Chenopodium album, leaf excision and light both increase urease (EC. 3.5.1.5) activity. Dithiothreitol (DTT), reduced glutathione (GSH), cysteine and diazoinedicarboxylic acid bis(N,N-dimethylamide) (diamide) activated the crude enzyme. In contrast, crude urease was inhibited by phenylmethylsulphonyl fluoride (PMSF) and Na-p -tosyl-L-lysine chloromethyl ketone HCl (TLCK), suggesting the pres...

2006
TOSHIO AOYAGI

The relationship postulated between hepatic coma and hyperammonaemia implicates the gastrointestinal tract as a major source of the excess ammonia in the peripheral blood of some patients with cirrhosis (Butt and Summerskill, 1961; Chalmers, 1960; Sherlock, Summerskill, White, and Phear, 1954). Conventional therapy, comprising protein restriction, antibiotics, and enemas, is directed toward eli...

Journal: :Gut 1995
O M Jolobe

The factors that determine which Helicobacter pylori infected subjects develop duodenal ulcer (DU) are unclear. This study tested the hypothesis that infection density and urease activity are higher in DU than non-DU subjects. Fifty five DU and 55 age and sex matched non-DU subjects were studied. Quantitative methods were used for measuring infection density (viable organism count) and urease a...

Journal: :Infection and immunity 2004
Arnoud H M van Vliet Ernst J Kuipers Jeroen Stoof Sophie W Poppelaars Johannes G Kusters

Although the adaptive mechanisms allowing the gastric pathogen Helicobacter pylori to survive acid shocks have been well documented, the mechanisms allowing growth at mildly acidic conditions (pH approximately 5.5) are still poorly understood. Here we demonstrate that H. pylori strain 26695 increases the transcription and activity of its urease, amidase, and formamidase enzymes four- to ninefol...

2010
Jong Seung Lee Yon Ho Choe Ji Hyuk Lee Hye Jin Lee Jee Hyun Lee Young Ok Choi

PURPOSE The role of the Ferric Uptake Regulator (FUR) in the acid resistance of Helicobacter pylori (H. pylori) has been thought to be independent of urease. However, we demonstrated in this study that Fur influences urease activity. MATERIALS AND METHODS A fur knockout mutant of H. pylori was constructed by replacing the Fur gene with a kanamycin resistant marker gene. The wild-type H. pylor...

Journal: :Infection and immunity 2001
L M Hansen J V Solnick

Helicobacter pylori strain J166 recovered from experimentally inoculated rhesus monkeys had up to a 250-fold-increased urease activity over that before inoculation. This was found to result from the selection of urease positive J166 clones from a heterogeneous inoculum, which was predominantly urease negative due to a 1-bp insertion in the ureA gene. These results confirm the importance of urea...

Journal: :Journal of bacteriology 2009
Erin L Benanti Peter T Chivers

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.

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