• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.532-534
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• 2005

Several extracts of Chinese herbs are known to have antimicrobial efface on Helicobacter pylori. The inhibition action is believed to be anti-urease activity of the substance in the herbs. In this study ethanol (70%) extracts of Mume Fructus showed anti-urease activity far better than previously reported substance such as Caesalpinia sappan L. and Forsythiae suspensa VAHL.

• Korean Journal of Poultry Science
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• v.22 no.2
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• pp.105-115
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• 1995

The balance of microbial populations in the gastrointestinal (GI) tract of all warm-blooded animals is critical to the maintenance of health and resistance to disease. The composition of the populations can be altered by diet and environment, making the host animal susceptible to disease, and reducing growth rate and feed efficiency. Some feed additives including antimicrobial agents, prohiotics or yucca extract have been used to promote growth and feed utilization. There is evidence that part of growth-promoting effect of those feed additives results from the suppression of microbial urease activity or ammonia production in the GI contents of animals. Over 200 microbial species have been known to produce urease and the product of urea hydrolysis, ammonia, is toxic to animals. Carefully tested probiotics or other urease-suppressing agents can be a possible alternative to antimicrobial agents including antibiotics as growth promotants used for animals feeds.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.531-536
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• 2009

A urease-positive bacterium isolated from sea water was identified as Photobacterium sp. by morphological, biochemical, and 16s rRNA gene analyses and named Photobacterium sp. strain HA-2. 2.0-fold increase enzyme activity was observed in LB medium containing 3% NaCl and 0.1% urea or not and the enzyme activity was 16.0-fold lower compared to urease-positive Vibrio parahaemolyticus AQ4673 strain when grown in the LB medium containing 3% NaCl with 0.1% urea. The cloning and sequencing of Photobacterium sp. strain HA-2 urease gene cluster is currently being analyzed in our laboratory.

• Geomechanics and Engineering
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• v.17 no.5
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• pp.421-427
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• 2019

Coastal erosion is becoming a significant problem in Greece, Bangladesh, and globally. For the prevention and minimization of damage from coastal erosion, combinations of various structures have been used conventionally. However, most of these methods are expensive. Therefore, creating artificial beachrock using local ureolytic bacteria and the MICP (Microbially Induced Carbonate Precipitation) method can be an alternative for coastal erosion protection, as it is a sustainable and eco-friendly biological ground improvement technique. Most research on MICP has been confined to land ureolytic bacteria and limited attention has been paid to coastal ureolytic bacteria for the measurement of urease activity. Subsequently, their various environmental effects have not been investigated. Therefore, for the successful application of MICP to coastal erosion protection, the type of bacteria, bacterial cell concentration, reaction temperature, cell culture duration, carbonate precipitation trend, pH of the media that controls the activity of the urease enzyme, etc., are evaluated. In this study, the effects of temperature, pH, and culture duration, as well as the trend in carbonate precipitation of coastal ureolytic bacteria isolated from two coastal regions in Greece and Bangladesh, were evaluated. The results showed that urease activity of coastal ureolytic bacteria species relies on some environmental parameters that are very important for successful sand solidification. In future, we aim to apply these findings towards the creation of artificial beachrock in combination with a geotextile tube for coastal erosion protection in Mediterranean countries, Bangladesh, and globally, for bio-mediated soil improvement.

• The Journal of the Korean Society for Microbiology
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• v.34 no.6
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• pp.533-542
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• 1999

H. pylori produces urease abundantly amounting to 6% of total protein of bacterial mass. Urease genes are composed of a cluster of 9 genes of ureC, ureD, ureA, ureB, ureI, ureE, ureF, ureG, ureH. Production of H. pylori urease in E. coli was studied with genetic cotransformation. Structural genes ureA and ureB produce urease apoprotein in E. coli but the apoprotein has no enzymatic activity. ureC and ureD do not affect urease production nor enzyme activity ureF, ureG, and ureH are essential to produce the catalytically active H. pylori urease of structural genes (ureA and ureB) in E.coli. The kinetics of activation of H. pylori urease apoprotein were examined to understand the production of active H. pylori urease. Activation of H. pylori urease apoprotein, pH dependency, reversibility of $CO_2$ binding, irreversibility of $CO_2$ and $Ni^{2+}$ incorporation, and $CO_2$ dependency of initial rate of urease activity have been observed in vitro. The intrinsic reactivity (ko) for carbamylation of urease apoprotein co expressed with accessory genes was 17-fold greater than that of urease apoprotein expressed without accessory genes. It is concluded that accessory genes function in maximizing the carbamylating deprotonated ${\varepsilon}$-amino group of Lys 219 of urease B subunit and metallocenter of urease apoprotein is supposed to be assembled by reaction of a deprotonated protein side chain with an activating $CO_2$ molecule to generate ligands that facilitate productive nickel binding.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.74-78
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• 2003

To determine the urease inhibitory activity of various heavy metal ions, a photometric cuvette assay for measuring ammonia production was developed. In this assay, the absorbance values at 630 m were linearly increased according to the ammonia concentrations up to 3.0 mg/l (r : 0.998). The urease inhibitions upon addition of a single species of heavy metal ions were in the decreasing order of Hg(II) > Pb(II) > Cu(II) > Cd(II) > Zn(II) ions. As expected, the urease inhibitions at a fixed concentration of a single species and at varying concentrations of other species occurred in the additive way. The above results show the applicability of the current method to the selective detection on Hg(II) ions as well as the screening of heavy metal ions possibly present at various samples.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.591-596
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• 2013

Urease activity of Helicobacter pylori was most strongly inhibited by extract of Mume Fructus among ethanol (70%, v/v) extract of 6 herbal materials selected from our previous work, database on traditional herbal materials, and literature data on Korean plant resources. Active compounds in the extract of Mume Fructus were separated by batch extraction, and further purified by chromatography in a silica gel column and an octadecyl silica gel column using solvents of different polarity. By NMR analysis of the last chromatographic fraction we identified ursolic acid as the active compound of urease inhibition. The result suggests that this component in Mume Fructus can possibly be used for the eradication of H. pylori.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.265-270
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• 2017

A key virulence factor for urinary tract pathogens is the enzyme urease, which catalyzes the hydrolysis of urea into ammonium ions and carbonic acid. Urease activity plays an important role in the pathogenesis of urinary tract infection. In this study, the inhibitory effect of zerumbone against six urease-producing bacteria (Klebsiella oxytoca, K. pneumoniae, Morganella morganii, Proteus mirabilis, P. vulgaris, and Staphylococcus saprophyticus) and their urease activities were evaluated. The results of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests showed that zerumbone had antibacterial effect against these six urease-producing bacteria. The MIC and MBC of zerumbone ranged from 0.5 to 2 mM and 1 to 4 mM, respectively. In the urease inhibitory assay, zerumbone showed better urease inhibition ($56.28{\pm}2.45-37.83{\pm}3.47%$) than the standard urease inhibitor, acetohydroxamic acid ($40.46{\pm}1.94-22.99{\pm}3.53%$). However, zerumbone did not affect the levels of the urease subunit. These results clearly indicated that zerumbone has antibacterial potential against urease-producing bacteria and possesses excellent bacterial urease inhibition properties.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.332.1-332.1
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• 2002

Streptococcus vestibularis is a urease-producing oral bacterium. frequently isolated from vestibular mucosa of human oral cavity. Ureolysis by S. vestibularis and other ureolytic oral bacteria is believed to be crucially involved in oral microbial ecology and oral health. Genomic library of the S. vestibularis ATCC49124 was constructed in an E. coli plasmid vector and the urease-positive transformants harboring the urease gene cluster were isolated on Christensen-urea agar plates. The minimal DNA region required for the urease activity was located on a 5.6 kb DNA fragment. (omitted)

• Natural Product Sciences
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• v.23 no.1
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• pp.46-52
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• 2017

The aim of this study was to evaluate the anti-Helicobacter pylori activity of fractions and major aglycon compounds (baicalein, chrysin, oroxylin A, wogonin) of Scutellariae Radix. Minimum inhibitory concentration (MIC) measurement, DPPH radical-scavenging assay, DNA protection assay, and urease inhibition analysis were performed. The ethyl acetate (EtOAc) fraction showed the potent anti-Helicobacter activity, and therefore, compounds in the EtOAc fraction were subjected to further assay. The MICs of chrysin, oroxylin A, and wogonin against Helicobacter pylori 26695 were 6.25, 12.5 and $25{\mu}g/mL$, respectively. Baicalein exhibited the most effective DPPH radical-scavenging activity. DNA protection using Fenton reaction, chrysin, oroxylin A, and wogonin showed effective DNA protective effect. This result was also confirmed by quantitative real-time polymerase chain reaction (qRT-PCR). Regarding Jack bean urease (0.5 mg/mL, 50 unit/mg) inhibition, 20 mM ofbaicalein and chrysin inhibited urease activity by 88.2% and 72.5%, respectively.