• 한국토양비료학회지
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• 제26권4호
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• pp.225-229
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• 1993

ammonium thiosulfate(ATS)의 urease 활성 억제제로서의 효과를 thiourea와 비교하고, 온도 및 pH가 ATS의 효과에 미치는 영향을 실험한 바, 그 결과를 요약하면 다음과 같다. 1. ATS의 요소 가수 분해 저해율은 $25^{\circ}C$에서 요소의 5% 수준으로 처리하였을 때에는 1.5~14.3%, 10% 처리시에는 7.6~20.5%였다. 이는 thiourea의 저해율보다 다소 낮은 수준이었다. 2. ATS의 효과는 고온보다는 저온에서 뚜렷하게 나타났다. 즉 요소의 10% 수준으로 처리하였을 때 $10^{\circ}C$와 $15^{\circ}C$에서의 가수 분해 저해율은 각각 62.6%와 41.7%였다. 3. 토양 pH에 따라서 ATS의 효과가 나타나기 시작하는 시간이 달랐다. 즉 pH가 6.0과 6.5에서는 24시간부터 저해 효과가 나타난 반면, 5.0과 7.0, 7.5에서는 48시간부터 효과가 나타났다. 처리후 72시간에 urease 활성 저해율은 pH에 관계없이 비슷하므로, pH와 저해 효과와는 일정한 경향성이 없는 듯하다.

• 한국식품과학회지
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• 제31권3호
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• pp.764-770
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• 1999

41종의 약용식물을 열수추출하여 위궤양 원인균으로 보고된 Helicobacter pylori에 대해 항균활성을 탐색하였다. 2-fold dilution 방법에 의해서는 백련초, 어성초, 방기, 황련은 100 ppm이하, 백두옹, 연교, 종대황, 소엽은 200 ppm 이하, 사간, 우방자, 결명자, 귤피, 희침, 소목은 300 ppm 이하와 농도에서 H. pylori에 대해 항균활성을 나타냈다. 이중 3가지 추출물만이 disc 방법을 통해 항균활성이 재확인되었으며, 소목, 황련, 소엽의 순으로 강한 항균활성을 나타냈다. 항균활성이 확인된 3가지 추출물을 chloroform, ethyl acetate, butanol로 순차 분획하여 H. pylori에 대한 항균활성을 확인하였다. 소목의 경우는 ethyl acetate 분획물에서, 소엽의 경우는 butanol 분획물에서, 황련의 경우는 butanol과 chloroform 분획물에서 가장 강한 항균활성을 나타내었다. 추출물의 분획에 따른 항균활성의 상승효과는 모든 추출물에서 확인할 수 있었다. H. pylori의 crude-urease를 분리하여 urea R broth에서 흡광도와 pH를 조사한 결과, 반응 2시간 후 pH가 8.15까지, 560 nm에서의 흡광도는 1.7까지 증가하는 것으로 나타났다. H. pylori의 urease 활성은 소목, 소엽, 황련에 의해 80%이상 억제되었으며, 이중 소목은 urease 활성을 95%이상 억제시켰다.

• Food Science and Biotechnology
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• 제15권3호
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• pp.466-468
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• 2006

The antimicrobial effect of a novel flavonoid (7-O-butyl naringenin) on Helicobacter pylori ATCC 26695 and its inhibitory effects on the urease activity of the strain were evaluated by comparing with quercetin and naringenin. H. pylori was cultured with brain heart infusion supplemented with 5% horse serum at $37^{\circ}C$ under 10% $CO_2$ atmosphere and the inhibitory effects of flavonoids against the strain were detected using micro-plate methods. During 12 hr of incubation time, the optical densities of phenol red reduced (pink color) in the urea broth by producing ammonia were detected at 560 nm with a spectrophotometer. The results indicated that both quercetin and 7-O-butyl naringenin were effective against the growth of H. pylori. Moreover, inhibitory effect of 7-O-butyl naringenin on the growth of H. pylori was about two-fold higher than quercetin at the same concentration. With regard to H. pylori urease activity, 7-O-butyl naringenin had a greater inhibitory effect than did naringenin or quercetin at the same concentration.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.3147-3149
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• 2009

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 제2회 추계심포지움
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• pp.69-80
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• 1994

Although ureases play important roles in microbial nitrogen metabolism and in the pathogenesis of several human diseases, little is known of the mechanism of metallocenter biosynthesis in this Ni-Containing enzyme. Klebsiella aerogenes urease apo-protein was purified from cells grown in the absence of Ni. The purified apo-enzyme showed the same native molecular weight, charge, and subunit stoichiometry as the holo-enzyme. Chemical modification studies were consistent with histidinyl ligation of Ni. Apo-enzyme could not be activated by simple addition of Ni ions suggesting a requirement for a cellular factor. Deletion analysis showed that four accessory genes (ureD, ureE, ureF, and ureG) are necessary for the functional incorporation of the urease metallocenter. Whereas the $\Delta$ureD, $\Delta$ureF, and $\Delta$ureG mutants are inactive and their ureases lack Ni, the $\Delta$ureE mutants retain partial activity and their ureases possess corresponding lower levels of Ni. UreE and UreG peptides were identified by SDS-polyacrylamide gel comparisons of mutant and wild type cells and by N-terminal sequencing. UreD and UreF peptides, which are synthesized at ve교 low levels, were identified by using in vitro transcription/translation methods. Cotransformation of E. coli cells with the complementing plasmids confirmed that ureD and ureF gene products act in trans. UreE was purified and characterized. immunogold electron microscopic studies were used to localize UreE to the cytoplasm. Equilibrium dialysis studies of purified UreE with $^{63}$ NiC1$_2$ showed that it binds ～6 Ni in a specific manner with a $K_{d}$ of 9.6 $\pm$1.3 $\mu$M. Results from spectroscopic studies demonstrated that Ni ions are ligated by 5 histidinyl residues and a sixth N or O atom, consistent with participation of the polyhistidine tail at the carboxyl termini of the dimeric UreE in Ni binding. With these results and other known features of the urease-related gene products, a model for urease metallocenter biosynthesis is proposed in which UreE binds Ni and acts as a Ni donor to the urease apo-protein while UreG binds ATP and couples its Hydrolysis to the Ni incorporation process.ouples its Hydrolysis to the Ni incorporation process.s.

• Archives of Pharmacal Research
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• 제19권6호
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• pp.447-449
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• 1996

Inhibitory effects of the mushrooms on the growth and urease of Helicobacter pylori (HP), which is associated with human gastroduodenal diseases such as gastritis, peptic ulcer and gastric carcinoma, were investigated. Most of the mushroom extracts did not show inhibitory effect on HP urease except Coriolus versicolar, Auricularia auricular Sarcodon aspratus and Flammulina velutipes. The extract of Ganoderma lucidum, Coriolus versicolar, Gyropora esculenta and Agaricus bisporus var. albidus inhibited the growth of HP. When their extracts were fractionated, the ether fraction of Ganoderma lucidum and Agaricus bisporus var. albidus were the most effective. Among seven components separated from the ether fraction of G. lucidum extract by silica gel column chromatography, P3 was the most potent: MIC was $200{\mu}g/ml$. However, P3 did not inhibit the urease.

• 한국토양비료학회지
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• 제31권4호
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• pp.392-399
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• 1998

본 연구에서는 합성 요소억제제나 질산화억제제와는 달리 쑥(Artemisia asiatica)과 같은 천연물에 의한 토양중 요소분해와 질산화작용에 대한 저해효과를 검토하고저 하였다. 이를 위 위하여 쑥의 열수추출액과 유기용매 분획추출물을 준비하여 밭토양에 처리하였고 2일, 5일 동안 배양후에 요소태질소와 암모늄태질소, 질산태 질소를 측정하고 요소분해균과 urease 효소활성에 대한 각 추출액과 분획추출물의 영향도 검토하였다. 이번 실험을 통하여 얻은 결과를 요약하면 다음과 같다. 쑥잎의 열수추출액은 요소분해를 미약한 수준으로 촉진하였으나 반면 질산화작용은 억제하였고, 쑥잎 열수추출액을 0.5ml, 3.0 ml를 가하였을 때 질산태 질소함량은 무처리구에 비하여 각각 65.2%, 68.8% 줄어들었다. 쑥잎의 유기용매 분획추출물 중, chloroform분획을 제외한 모든 분획물이 요소분해에 대해 저해효과를 나타내었고 chloroform/methanol 분획을 2.0 ml 가했을 때, 잔존한 요소태질소 함량은 무처리구의 5.8배로 요소분해억제효과가 가장 좋았다. 한편 유기용매 분획추출물들의 질산화작용 억제효과 유무는 불명확 하였다. urease activity의 경우, 요소분해율이 무처리구와 비교시 97.5%에서 99.50%로 높게 나타났기 때문에 분획물이 urease의 활성을 저해하지 않는 것으로 생각되었다. 요소분해 bacteria 수는, 쑥의 chloroform 분획을 처리한 경우를 제외하고 모든 처리에 의해 감소하였다 (적요 2의 결과와 일치). 이로서 요소분해 저해효과는 urease의 활성을 저해하기 보다는 요소분해균을 저해하기 때문에 나타나는 것으로 생각되었다. 각 추출물 성분에 대한 예비시험과 박층 chromatogram을 통해, 그 조성이 복잡하고 다양한 화합물들이 요소분해와 질산화작용 억제과정에 관여할 것으로 추측되며 이를 분획 또는 단일활성 물질을 추적하여 그 효과를 확인할 일이다.

• 한국토양비료학회지
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• 제47권6호
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• pp.391-397
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• 2014

Acid mine drainage occurrence is a serious environmental problem by mining industry; it usually contain high levels of metal ions, such as iron, copper, zinc, aluminum, and manganese, as well as metalloids of which arsenic is generally of greatest concern. It causes mine impacted soil pollution with mining and smelting activities, fossil fuel combustion, and waste disposal. In the present study, three bacterial strains capable of producing urease were isolated by selective enrichment of heavy metal contaminated soils from a minei-mpacted area. All isolated bacterial strains were identified Sporosarcina pasteurii with more than 98% of similarity, therefore they were named Sporosarcina sp. KM-01, KM-07, and KM-12. The heavy metals detected from the collected mine soils containing bacterial isolates as Mn ($170.50mg\;kg^{-1}$), As ($114.05mg\;kg^{-1}$), Zn ($92.07mg\;kg^{-1}$), Cu ($62.44mg\;kg^{-1}$), and Pb ($40.29mg\;kg^{-1}$). The KM-01, KM-07, and KM-12 strains were shown to be able to precipitate calcium carbonate using urea as a energy source that was amended with calcium chloride. SEM-EDS analyses showed that calcium carbonate was successfully produced and increased with time. To confirm the calcium carbonate precipitation ability, urease activity and precipitate weight were also measured and compared. These results demonstrate that all isolated bacterial strains could potentially be used in the bioremediation of acidic soil contaminated by heavy metals by mining activity.

• Fisheries and Aquatic Sciences
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• 제5권3호
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• pp.178-182
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• 2002

The authors identified 68 Vibrio strains from Gwangan beach seawater from June to October in 2001. We identified them as 19 strains of Vibrio alginolyticus, 15 strains of V. vulnificus, 15 strains of V. parahaemolyticus, 11 strains of V. cholerae non O1, 7 strains of V. fluvialis and just one strain of V. hollisae. They showed their typical biochemical characteristics by API 20E kit (bioMerieux), respectively. It was examined whether their cultural supernatants had enzymatic activities such as hemolysin, protease or urease. The 46 strains showed hemolytic activities and/or protease activities. But we could not find any strain which had urease activity. All isolates of V. cholerae non O1 showed $\beta$ hemolysis. The others showed $\alpha$ hemolysis or did not show clear zones on sheep blood agar plates. These results of Kanagawa phenomenon were not always correspondant with hemolytic activities of cultural supernatants at late log phase. Some strains had higher hemolytic activities despite of showing protease activities on skim milk agar plates and in litmus milk media. On the other hand, some strains showed protease activities but did not show hemolytic activities. Therefore we could guess that there were the relationships between hemolysins and proteases produced by pathogenic vibrios.

• Journal of Applied Biological Chemistry
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• 제58권1호
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• pp.89-95
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• 2015

Helicobacter pylori infection causes gastrointestinal diseases such as chronic gastritis, peptic ulcers, and may lead to gastric cancer. Several studies have reported that lactobacilli present on broccoli show inhibitory activity against H. pylori. Here, we evaluated aqueous broccoli, fermented by Lactobacillus plantarum MG208, for its fermentation characteristics and anti-H. pylori activities including antibacterial activity, growth inhibition, anti-adhesion, and urease inhibition. The results indicated that the fermentation characteristics changed significantly depending on the amount of aqueous broccoli used for fermentation (p <0.05). There was no significant difference between the samples before fermentation (p >0.05). However, a significant concentration-dependent difference was noted in antibacterial activity and urease inhibition (p <0.05) following the addition of aqueous broccoli. Growth inhibition in the 10 mg/mL sample was significantly higher as compared to the negative control and similar to that with amoxicillin (positive control) (p <0.05). Anti-adhesion activity of aqueous broccoli was also significantly different (p <0.05) from the negative control. Therefore, aqueous broccoli fermented by L. plantarum MG208 could prove useful as a functional diet for protection of the gastric environment against H. pylori infection.