• Title/Summary/Keyword:  inhibition

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Dibucaine Inhibition of Serum Cholinesterase

  • Elamin, Babiker
    • BMB Reports
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    • v.36 no.2
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    • pp.149-153
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    • 2003
  • The dibucaine number (DN) was determined for serum cholinesterase (EC 3.1.1.8, SChE) in plasma samples. The ones with a DN of 79-82 were used, because they had the "usual" SChE variant. The enzyme was assayed colorimetrically by the reaction of 5,5'-dithiobis-[2-nitrobenzoic acid] (DTNB) with the free sulfhydryl groups of thiocholine that were produced by the enzyme reaction with butrylthiocholine (BuTch) or acetylthiocholine (AcTch) substrates, and measured at 412 nm. Dibucaine, a quaternary ammonium compound, inhibited SChE to a minimum within 2 min in a reversible manner. The inhibition was very potent. It had an $IC_{50}$ of $5.3\;{\mu}M$ with BuTch or $3.8\;{\mu}M$ with AcTch. The inhibition was competitive with respect to BuTch with a $K_i$ of $1.3\;{\mu}M$ and a linear-mixed type (competitive/noncompetitive) with respect to AcTch with inhibition constants, $K_i$ and $K_I$ of 0.66 and $2.5\;{\mu}M$, respectively. Dibucaine possesses a butoxy side chain that is similar to the butryl group of BuTch and longer by an ethylene group from AcTch. This may account for the difference in inhibition behavior. It may also suggest the existence of an additional binding site, other than the anionic binding site, and of a hydrophobic nature.

Inhibition effect of silica nanoparticle on the oxygen uptake rate of activated sludge (실리카 나노입자에 의한 활성슬러지 활성도 저해 효과 분석)

  • Lee, Soo Mi;Cho, Jin Woo
    • Journal of Korean Society of Water and Wastewater
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    • v.28 no.1
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    • pp.47-54
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    • 2014
  • Nanotechnology has become one of the fastest developing technologies and recently applied to a variety of industries. Thus, increasing number of nano materials including various nanoparticles would be discharged into wastewater and consequently entering a biological wastewater treatment process. However, the impact of the nano particles on biological wastewater treatment has not been estimated intensively. In this research, we investigated the effect of silica nanoparticle on the oxygen uptake rates (OURs) of activated sludge used in a conventional wastewater treatment process. The inhibition (%) values were estimated from the results of OURs experiments for the silica nanoparticles with various sizes of 10-15, 45-50, and 70-100 nm and concentrations of 50, 250, and 500 ppm. As results, the inhibition value was increased as the size of silica nano particles decreased and the injected concentration increased. The maximum inhibition value was investigated as 37.4 % for the silica nanoparticles with the size of 45-50 nm and concentration of 50 ppm. Additionally, the effect of size and concentration on the inhibition should be considered cautiously in case that the aggregation of particles occurred seriously so that the size of individual particles was increased in aquatic solution.

Hydrodynamic Effect on the Inhibition for the Flow Accelerated Corrosion of an Elbow

  • Zeng, L.;Zhang, G.A.;Guo, X.P.
    • Corrosion Science and Technology
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    • v.16 no.1
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    • pp.23-30
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    • 2017
  • The inhibition effect of thioureido imidazoline inhibitor (TAI) for flow accelerated corrosion (FAC) at different locations for an X65 carbon steel elbow was studied by array electrode and computational fluid dynamics (CFD) simulations. The distribution of the inhibition efficiency measured by electrochemical impedance spectroscopy (EIS) is in good accordance with the distribution of the hydrodynamic parameters at the elbow. The inhibition efficiencies at the outer wall are higher than those at the inner wall meaning that the lower inhibition efficiency is associated with a higher flow velocity, shear stress, and turbulent kinetic energy at the inner wall of the elbow, as well as secondary flow at the elbow rather than the mass transport of inhibitor molecules. Compared to the static condition, the inhibition efficiency of TAI for FAC was relatively low. It is also due to a drastic turbulence flow and high wall shear stress during the FAC test, which prevents the adsorption of inhibitor and/or damages the adsorbed inhibitor film.

Inhibition of Bacterial Growth with Silver Wire Iontophoresis (은 이온도입이 세균성장에 미치는 영향)

  • Lee Jae-Hyoung;Kim Joo-Young;Jekal Seung-Joo
    • The Journal of Korean Physical Therapy
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    • v.7 no.1
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    • pp.61-67
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    • 1995
  • The silver cation has broad-spectrum antibiotic activity toward Gram-positive, Gram-negative, fungal. aerobic and anerobic micro-organisms. Silver has been used to care of infected wound. pyogenic arthritis, and chronic osteomyelitis. The purpose of this study was to determine whether pure silver wire iontophoresis using milliamperage direct current has an inhibitory effect on growth in vitro of 3 different species of bacteria-Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Using agarose based media, silver iontophoresis performed at 0, 1, 2, 4, 8 mA for 15 minutes. All experiments were performed in triplicate. Following iontophoresis, inhibition zone width of bacterial growth was measured with calliper. The inhibition of bacterial growth occured at the anodal silver electrode. Inhibition zone width of bacterial growth was significantly increased in all three bacterial species (p<0.05). Between bacterial species, inhibition zone width was not significantly different. Inhibition gone and amperage showed a highly significant positive linear relationship (p<0.001). The result of this study showed that pure silver wire iontophoresis with milliamperage direct current, as well as microamperage direct current, can inhibit bacterial growth in vivo.

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Comparative Study of Corrosion Inhibition in Acidic and Neutral Chloride Media by Some Amino Acids (염산과 NaCl 수용액에서 알루미늄의 부식에 미치는 아미노산의 부식억제효과)

  • Yoon, Jonghwa;Kim, Younkyoo
    • Journal of the Korean Chemical Society
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    • v.62 no.5
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    • pp.364-371
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    • 2018
  • Inhibition effects of alanine (Ala), histidine (His), methionine (Met) on the corrosion of aluminum were investigated in deaerated 0.5 M HCl and NaCl solution. In HCl solution the inhibition efficiency for the aluminum corrosion depended on the cathodic inhibition, and the inhibition efficiency was increased in the order of Met$10^{-4\;}M$ the adsorption process can be explained by Langmuir isotherm, however, in the case of higher concentration by Temkin logarithmic isotherm due to the interaction between the adsorbed molecules.

Potent Selective Inhibition of Monoamine Oxidase A by Alternariol Monomethyl Ether Isolated from Alternaria brassicae

  • Lee, Hyun Woo;Kim, Yeon Ji;Nam, Sang-Jip;Kim, Hoon
    • Journal of Microbiology and Biotechnology
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    • v.27 no.2
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    • pp.316-320
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    • 2017
  • Alternariol monomethyl ether (AME), a dibenzopyrone derivative, was isolated from Alternaria brassicae along with altertoxin II (ATX-II). The compounds were tested for the inhibitory activity of monoamine oxidase (MAO), which catalyzes neurotransmitting monoamines. AME was found to be a highly potent and selective inhibitor of human MAO-A with an $IC_{50}$ value of $1.71{\mu}M$; however, it was found to be ineffective for MAO-B inhibition. ATX-II was not effective for the inhibition of either MAO-A or MAO-B. The inhibition of MAO-A using AME was apparently instantaneous. MAO-A activity was almost completely recovered after the dilution of the inhibited enzyme with an excess amount of AME, suggesting AME is a reversible inhibitor. AME showed mixed inhibition for MAO-A in Lineweaver-Burk plots with a $K_i$ value of $0.34{\mu}M$. The findings of this study suggest that microbial metabolites and dibenzopyrone could be potent MAO inhibitors. In addition, AME could be a useful lead compound for developing reversible MAO-A inhibitors to treat depression, Parkinson's disease, and Alzheimer's disease.

ANTIMICROBIAL EFFECT OF ROOT CANAL CEMENTS ON MICROORGANISMS FROM INFECTED ROOT CANALS (수종 근관 충전재의 항균 효과에 관한 연구)

  • Koh, Young-Hoon;Choi, Ho-Young
    • Restorative Dentistry and Endodontics
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    • v.16 no.1
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    • pp.190-199
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    • 1991
  • The purpose of this study was to evaluate the antimicrobial effect of root canal cements such as AH-26, Sealapex, Canals and Apatite root sealers(Type I, II, III) and to determine the efficacy of their activities. S.mutans(AHT), S.sanguis(NCTC 9811) and B.gingivalis(381) were streaked on blood agar and the PVC tybes filled with root canal cements were applied on. Then the microorganisms were cultured for 48 hours, anaerobically. B.cereus(KCTC 1012) was streaked on nutrient agar, PVC tubes were applied on and were cultured for 48 hours, aerobically. The inhibition zones of root canal cements were measured with vernier caliper. The data statistically analyzed, and the results were as followed. 1. Apatite root sealers(Type I, II, III) showed no inhibition zones. 2. AH-26, Sealapex and Canals had inhibition zones with varying degrees. The inhibition zone of AH-26 was greatest and followed by Canals and Sealapex(P<0.01). 3. As time goes by after mixing the root canal cements, AH-26, Canals and Sealapex showed significantly reducing inhibition zones(P<0.01). 4. There were the least inhibition zones of all the root canal cements on S.mutans and followed in such order as; B.gingivalis, S.sanguis and B.cereus(P<0.01).

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Effects of Dimaine, Diacid and Dintitro Derivatives on the Inhibition of Adenosine Deaminase; Experimental, Molecular Docking and QSAR Studies

  • Ajloo, Davood;Najafi, Leila;Saboury, Ali Akbar
    • Bulletin of the Korean Chemical Society
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    • v.30 no.11
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    • pp.2523-2531
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    • 2009
  • Effects of some diacid, diamine and dinitro aromatic compounds on the structure and activity of adenosine deaminase (ADA) were investigated by UV-Vis spectrophotometry in 50 mM phosphate buffer at pH = 7.5 and 27 ${^{\circ}C}$ and molecular docking studies. The results showed that all tested ligands are showing inhibition; five ligands are uncompetitive and other two ligands are mixed of competitive and noncompetetive inhibitors with majority of competitive behavior. For the later case analysis was done based on competitive inhibition. Diacids have larger size and higher inhibition constant ($K_I$) relative to others. A logical correlation between calculated free energy of binding and experimental values was obtained for un-competitive. Experimental and calculated data showed that competitive inhibitors are distributed near the active site of enzyme and form several cluster of ranks, whereas uncompetitive inhibitors bind to the enzyme-substrate complex and distributed far from the active site. Results of structure-activity relationship showed that, larger, more hydrophobe, less spherical and more aromatic ligands have higher inhibition constants.

A STUDY ON THE ANTIBACTERIAL EFFECT OF RESTORATIVE MATERIALS (수복재의 항균효과에 관한 연구)

  • Jeong, Hee-Il;Im, Mi-Kyung;Choi, La-Young;Han, Du-Seok
    • Restorative Dentistry and Endodontics
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    • v.17 no.1
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    • pp.134-140
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    • 1992
  • The purpose of this study was to investigate the antibacterial effect of zinc oxide eugenol(ZOE), zinc phosphate cement(ZPC), glass ionomer cement, resin, and Vitapex to S. muntans, S. sanguis, S. fecalis and E. coli by agar diffusion method. Four wells were punctured in mitis-salivarius agar plate per each group and each wells were filled with restorative matetials. The width of inhibition zones produced in mitis - salivarius agar were measured as the parameter of the antibacterial effect after 16 hours and 40 hours. In S. mutans and S. sanguis, the largest inhibition zone was produced on ZOE, followed by glass ionomer cement, and ZPC. Inhibition zones was not observed in resin and Vitapex. In S. fecalis, ZOE and glass ionomer cement showed wider inhibition zone than ZPC. In E. coli, ZOE showed wider inhibition zone than ZPC, but no inhibition zone was observed on glass ionomer cement.

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Physiological Activity of Extracts of Bark from Ulmus davidiana var. japonica and its fractions (유근피 추출물 및 분획의 생리활성)

  • Yang, Sun a;Kim, A young;Pyo, Byoung sik;Kim, Sun min
    • Korean Journal of Pharmacognosy
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    • v.50 no.2
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    • pp.112-117
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    • 2019
  • In this study, extracts of bark from Ulmus davidiana var. japonica and its fractions were investigated the antioxidative, antibacterial and tyrosinase inhibition activity for physiological activity towards functional applications. In the measurement of DPPH radical scavenging activity, the ethyl acetate fraction showed higher radical scavenging ability than others. Moreover, in the tyrosinase inhibition assay, showed that the ethyl acetate fraction has good inhibition effects. Results of the DPPH radical scavenging and tyrosinase inhibition activity are related with the total polyphenol concentrations of ethyl acetate fraction. In antibacterial activity used to find out by utilizing the disc diffusion assay, chloroform fraction showed strong effect against Staphylococcus aureus and S. epidermidis. These results are related with the flavonoid contents of chloroform fraction. On the other hand, in the L929 cell viability measurement by MTT assay, the hexane, butanol and aqueous fraction treated at high concentration were showed cytotoxicity. But the others samples were exhibited a moderate viabilities. As a result of investigated the antioxidant and tyrosinase inhibition activity, the ethyl acetate fraction could be applicable for cosmetics related fields. And the chloroform fraction showed significant antibacterial activity against S. aureus and S. epidermidis.