• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.330-336
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• 2005

Lactococcus lactis A164 is a nisin Z-producing strain isolated from kimchi. Its antimicrobial spectrum has been found to be active against most Gram-positive bacteria tested, yet inactive against Gram-negative bacteria [3]. Accordingly, to overcome this drawback, the current study attempted to express human $\beta$-defensin-l (hBD-l), which kills both Gram-positive and Gram-negative bacteria in L. lactis AI64. When the hBD-l cDNA was introduced using a nisin Z-controlled expression cassette, the L. lactis A164 transformants grew very poorly, due to the bactericidal effect of the expressed hBD-l against the transformants. Therefore, a gene fusion system was designed to reduce the toxicity of the expressed heterologous protein against the host cells. As such, the hBD-l gene was fused to the DsbC- Tag of pET -40b(+), then introduced to L. lactis A 164. The transformants expressed an intracellular 35.6-kDa DsbC-hBD-l fusion protein that exhibited slight activity against the host cells, yet not enough to strongly inhibit the cell growth. To obtain the recombinant hBD-l, the DsbC-hBD-l fusion protein was purified by nickel-affinity column chromatography, and the DsbC-Tag removed by cleaving with enterokinase. The cleaved mature hBD-l exhibited strong bactericidal activity against E. coli JM109, indicating that the recombinant L. lactis A 164 produced a biologically active hBD-I. In addition, the recombinant L. lactis A 164 was also found to produce the same level of nisin Z as the wild-type.

• Natural Product Sciences
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• 제11권3호
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• pp.150-154
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• 2005

The radical scavenging effect of the MeOH extract of Fraxini Cortex on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The $CH_2Cl_2$-and n-BuOH-soluble fractions of MeOH extract showed the promising DPPH radical scavenging effects, and further purified by silica gel, Sephadex LH-20 column chromatography, and reversed-phase C-18 MPLC to yield five coumarins, esculetin (1), fraxidin (2), fraxetin (3), fraxidin $8-O-{\beta}-D-glucopyranoside$ (fraxin methyl ether) (5), esculin (6), and a secoiridoid oleuropein (4), and a coumarin-secoiridoid escuside (7). Compounds 1, 3, and 4 showed potent DPPH radical scavenging effects, exhibiting $IC_{50}$ values of 14.68, 9.64, and $22.03\;{\mu}M$, respectively. Compounds 6 and 7 also showed moderate effects with $IC_{50}$ values of 147.79 and $72.73\;{\mu}M$, respectively. L-Ascorbic acid was used as a positive control and exhibited the $IC_{50}$ value of $50.31\;{\mu}M$.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.187-191
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• 2003

The motion and time-mean drift force of a 2-D floating BBDB in waves are studied with and without taking account of fluctuating air pressure in the air chamber. It has been found numerically that the drift for a of the BBDB is in the reverse direction of propagation of the incident waves over specific frequency ranges as found by McCormick through his experiment work. The drift force is calculated by Pinkster's near-field method. Since Maruo's formula method for the drift force is always positive, Maruo's formula is only approximate and should be replaced by the correct near-field method.

• BMB Reports
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• 제43권4호
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• pp.284-290
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• 2010

Replication of positive-strand RNA virus is mediated by a virus-encoded RNA-dependent RNA polymerase (RdRp). To study the replication of Ectropis obliqua virus (EoV), a newly identified insect virus belonging to the family Iflaviradae, we expressed the RNA polymerase domain in Escherichia coli and purified it on a Ni-chelating HisTrap affinity column. It is demonstrated that EoV RdRp initiated RNA synthesis in a primer and poly (A)-dependent manner in vitro. Furthermore, the effect of primer concentration, temperature, metal ions ($Mg^{2+}$, $Mn^{2+}$, and $K^+$) on enzymatic activity were determined. Our study represented a first step towards understanding the mechanism of EoV replication.

• Asian Journal of Atmospheric Environment
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• 제10권1호
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• pp.22-31
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• 2016

Active fire products from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observation during the 16 years from 2000-2015 were analyzed to estimate spatial and temporal variations of wildland fires over East Asia (region of interest: $20^{\circ}N-55^{\circ}N$, $100^{\circ}E-150^{\circ}E$). GLOBCOVER 2009 land cover data were also used to investigate the trend in wildfire occurrence with respect to each land cover type. Statistical analysis showed that the highest number of wildland fires occurred in the evergreen and vegetation covered areas, and strong seasonal variations were found in these areas. Total numbers of fires were 283,683 and 202,543, respectively. In particular, the wildland fires in croplands occurred mainly during summer season and distinguishable increasing trends were found. The correlations between number of wildland fires and air pollutants, such as black carbon, organic matter, and carbon monoxide, were also calculated in order to investigate the intensity of the air pollution caused by the wildland fires. Positive correlation between total column carbon monoxide contents and the occurrence of wildland fire was found. In addition, this correlation was higher than the correlation between fire occurrence and black carbon or organic matter. These results indicate that a significant amount of carbon monoxide originated from the wildland fires and influenced the regional atmospheric environment in East Asia.

• 한국작물학회지
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• 제38권1호
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• pp.60-65
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• 1993

7개 재배지역산 참당귀의 decursin 함량변이를 조사하였으며, 각 재배지의 기상요인들과의 상관분석을 통하여 기상환경이 당귀 근의 decursin 함량에 미치는 영향을 파악하고자 수행된 실험결과는 다음과 같다. 1. 참당귀 근의 유효성분인 decursin과 decursinol angelate의 정량은 순상컬럼을 사용한 HPLC법이나 GC법이 양호하였다. 2. 참당귀 뿌리의 decursin 함량은 봉화산 4. 86%, 영천산 4.75%이며 수원산은 2.33%로 재배지역에 따른 함량변이가 비교적 컸다. 3. 생육기간별 각 기상요인들과 decursin 함량과의 상관분석 결과 통계적 유의상관은 보이지 않았으나, 평균기온과 강수량은 대체적으로 부의 상관을 보였으며 일교차, 일사량, 일조시수등은 정의 상관을 나타냈다.

• ALGAE
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• 제26권2호
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• pp.201-208
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• 2011

A monoterpene lactone, loliolide was successively isolated from brown seaweed, Sargassum ringgoldianum subsp. coreanum using column chromatography and high-performance liquid chromatography. The structure of the isolated compound was determined by comparison of EIMS and NMR spectral data with the previously published data. The antioxidant activities of loliolide were also evaluated by DPPH and $H_2O_2$ radical and intracellular reactive oxygen species scavenging assays, and it showed moderate activities in all antioxidant assays. Furthermore, loliolide was found to exert positive dose-dependent effects in the protective effects against $H_2O_2$-induced cell damage which were determined via MTT, Hoechst staining assays and cell cycle analysis. This is the first study on chemical constituent of this seaweed according to our best knowledge. These results clearly indicated that loliolide isolated from Sargassum ringgoldianum subsp. coreanum can protect the cells against $H_2O_2$-induced cell damage or apoptosis.

• Toxicological Research
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• 제29권3호
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• pp.203-209
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• 2013

A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of ${\varepsilon}$-acetamidocaproic acid (AACA), the primary metabolite of zinc acexamate (ZAC), in rat plasma by using normetanephrine as an internal standard. Sample preparation involved protein precipitation using methanol. Separation was achieved on a Gemini-NX $C_{18}$ column ($150mm{\times}2.0mm$, i.d., 3 ${\mu}m$ particle size) using a mixture of 0.1% formic acid-water : acetonitrile (80 : 20, v/v) as the mobile phase at a flow rate of 200 ${\mu}l/min$. Quantification was performed on a triple quadrupole mass spectrometer employing electrospray ionization and operating in multiple reaction monitoring (MRM) and positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of AACA were linear over the concentration range of 20~5000 ng/ml in rat plasma. The coefficient of variation and relative error at four QC levels were ranged from 1.0% to 5.8% and from -8.4% to 6.6%, respectively. The present method was successfully applied for estimating the pharmacokinetic parameters of AACA following intravenous or oral administration of ZAC to rats.

• 생약학회지
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• 제35권4호통권139호
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• pp.350-356
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• 2004

In a preliminary screening of plant extracts for the antigastritic and anti- Helicobacter pylori (H. pylori) actions in rats, the ethanol extract of Amomi Semen (AS) showed positive activity in HCl Ethanol-induced gastric lesions and H. pylori. Among the systematic fractions of hexane, chloroform, butanol and water, the most potent butanol fraction significantly reduced HCl, Ethanol-induced gastric lesions at the oral dose of 350 mg/kg. Also butanol fraction has an inhibitory effect on the growth of H. pylori $(MIC=1.43\;{\mu}g/mL)$. In pylorus ligated rats, butanol fraction showed decrease in the volume of gastric secretion and acid output, of which effects were stronger in other fractions. We isolated 6 subfractions by column chromatography. The protective effects of 6 subfractions of Amomi Semen were also significant in the HCl, Ethanol induced gastric lesion model. These results might suggest that they had inhibitory action in gastric lesion through inhibition of gastric acid secretion. Butanol fraction of AS can be applied as treatment of H. pylori. Butano fractions and ethanol extract of AS was carried out or the development of a new gastroprotective supplementary product.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1221-1227
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• 2011

Ethyl pyruvate (EP) is known as a scavenger of reactive oxygen species (ROS) in the body through its role in the donation of diketone groups to metals to form an EP-metal complex. In order to develop a method for the quantification of EP in biological media, a sensitive and specific, high-performance liquid chromatographyelectrospray ionization-mass spectrometry (HPLC-ESI/MS) method is used to determine the EP-alkali metal ion binding species. The analyte was separated on a ZORBOX SB-C8 ($3.5{\mu}m$, $30mm{\times}2.1mm$ I.D.) column and analyzed in selected ion monitoring (SIM) mode with a positive ESI interface using the m/z 255 $[2M + Na]^+$ ion. The method was validated over the concentration range of $0.5-60.0\;{\mu}g$/mL under 1/9 (v/v) of acetonitrile/methanol solvent system with flow rate 0.05 mL/min. The limit of quantification (LOQ) was $0.5{\mu}g$/mL.