نتایج جستجو برای: urease activity

تعداد نتایج: 1137208  

Journal: :Applied and environmental microbiology 2008
Maarten Mols Tjakko Abee

The presence and activities of urease genes were investigated in 49 clinical, food, and environmental Bacillus cereus isolates. Ten strains were shown to have urease genes, with eight of these strains showing growth on urea as the sole nitrogen source. Two of the urease-positive strains, including the sequenced strain ATCC 10987, could not use urea for growth, despite their capacities to produc...

2014
Tayyaba Huma Arooma Maryam Tahir ul qamar

In agriculture high urease activity during urea fertilization causes substantial environmental and economical problems by releasing abnormally large amount of ammonia into the atmosphere which leads to plant damage as well as ammonia toxicity. All over the world, urea is the most widely applied nitrogen fertilizer. Due to the action of enzyme urease; urea nitrogen is lost as volatile ammonia. F...

Journal: :Journal of bacteriology 1967
D R Morris K L Koffron

Cultures of Escherichia coli B and K-12 produce urea during growth in minimal medium. Results of isotopic labeling experiments were consistent with the sole source of urea being from the conversion of arginine to putrescine. Since E. coli itself has no demonstrable urease activity, the rate of urea production is a measure of the flux through the arginine to putrescine pathway.

2014
Mahmood Biglar Hessameddin Sufi Kowsar Bagherzadeh Massoud Amanlou Faraz Mojab

Infection with Helicobacter pyloriis the most common cause of stomach and duodenal ulcers. About more than 80 % of people are infected with H. pylori in developing countries. H. pylori uses urease enzyme product "ammonia" in order to neutralize and protect itself from the stomach acidic condition and urease enzyme activity has been shown to be essential to the colonization of H. pylori. Inhibit...

Journal: :Infection and immunity 1997
S G Lee D H Calhoun

Strain SL100 is a gram-positive coccoid isolate prototype with an adhesin specific for gastric mucin and is representative of potentially pathogenic organisms obtained at biopsy from patients with gastric disorders. The urease of this isolate constitutes a significant fraction of the total cell protein, and the outcome of the purification strategy described herein suggests that it is associated...

Journal: :Infection and immunity 2000
R Weltzin B Guy W D Thomas P J Giannasca T P Monath

The heat-labile toxin (LT) of Escherichia coli is a potent mucosal adjuvant that has been used to induce protective immunity against Helicobacter felis and Helicobacter pylori infection in mice. We studied whether recombinant LT or its B subunit (LTB) has adjuvant activity in mice when delivered with H. pylori urease antigen via the parenteral route. Mice were immunized subcutaneously or intrad...

2014
Nazar Abdulameer Hamzah

Novel sources of urease from leguminosae were selected for activity test, one the them (Prosopis farcta) showed high specific activity (36.52 U mg). The active uerase extract then subjected to series of purification steps involved salting out, DEAE, CM ion exchange and size exclusion chromatography. Specific activity were 52.44, 193.27, 230.55, 433.33 U mg respectively. Main features of urease ...

2013
Lirong Tan Jiyan Su Dianwei Wu Xiaodan Yu Zuqing Su Jingjin He Xiaoli Wu Songzhi Kong Xiaoping Lai Ji Lin Ziren Su

Baicalin (BA) is the principal component of Radix Scutellariae responsible for its pharmacological activity. In this study, kinetics and mechanism of inhibition by BA against jack-bean urease were investigated for its therapeutic potential. It was revealed that the IC₅₀ of BA against jack-bean urease was 2.74 ± 0.51 mM, which was proved to be a competitive and concentration-dependent inhibition...

Journal: :Journal of clinical pathology 1990
D B Winter S N McDermott

A new method of detecting urease activity in Enterobacteriaceae was developed. An 8.5 cm filter paper disc impregnated with 20% urea and 0.5% bromocresol purple was placed on the surface of a glucose fermentation plate after inoculation with a multipoint replicator and overnight incubation. This method was compared with the commercially prepared Mast urea agar (Multipoint) and Fuscoe's Urea Pla...

Journal: :Environmental science and pollution research international 2013
Maria Maleva Galina Borisova Nadezda Chukina Galina Nekrasova M N V Prasad

This paper analyzes the effect of exogenous urea in increased concentration gradient (0, 100, 500 and 1,000 mg L(-1)) on photosynthetic pigments (measured spectrophotometrically), uptake of (14)CO2 (using radioisotope), and urease activity (by measuring ammonia with Nessler's reagent) in leaves of Elodea densa Planch. We have observed that low concentration of urea (100 mg L(-1)) stimulates the...

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