• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.219-225
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• 2006

Bacterial community structure in the Juam Reservoir was analysed using fluorescent in situ hybridization (FISH) technique from April 2005 to January 2006. Total bacterial numbers varied in the range of 1.58 ${\sim}\;2.73{\times}\;10^6\;cells\;mL^{-1}$ proportional to the concentration of chi-a and had the minimal value in January. The ratios of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclass proteobacteria and Cytophaga-Flavobacterium (CF) group to total bacteria ranged from 45.1% to 77.5%, and the ratios of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclasses to total bacteria in June and September with the concentration of chi-a measured were lower than those ratios in April and January. It suggests that enriched growth of Microcystis aeruginosa may inhibit the metabolic activlty of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclass proteobacteria. However, the ratio of CF group bacteria represented no large change depending on algal bloom. In terms of nitrifying bacteria, the numbers of ammonia-oxidizing bacteria ranged from 9.9 ${\times}\;10^4\;to\;25.5\;{\times}10^4\;cells\;mL^{-1}$ with sharp fluctuation whereas those of nitrite-oxidizing bacteria varied in 8.7${\sim}9.8{\times}10^4\;cells\;mL^{-1}$ without noticeable change except the maximal value of $20.3{\times}10^4\;cells\;mL^{-1}$ in January maybe due to the high DO.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.4
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• pp.237-247
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• 1991

To characterize the community structure and spatial distribution of phytoplankton, observations on seawater temperature, salinity, nutrients, primary productivity and abundance and species composition of phytoplankton were made in the polar front region and its neighborhood off the east coast of Korea in summer 1990. Among the 96 taxa identified, Rhizosolenia setigera and Thalassionema nitzschioides were the most dominant species. The assemblage at the surface and 50 m depth was quite different in the northern inshore part of the study area but similar in the southern and offshore part. Principal component analysis by the species abundance showed that the phytoplankton consisted of the communities representing the surface of the northern inshore part with the neritic-warm dinoflagellates, the Northern Korean Cold Water with the cold water diatoms and the southern and offshore part, which seems to represent the Eastern Korean Warm Water, with the warm water diatoms. At the frontal region, diatoms were mixed with warm and cold water species. Primary productivity and phytoplankton standing crops were higher at the front than the neighboring waters. Nutrients were markedly high at the Northern Korean Cold Water. Horizontal advection of the Northern Korean Cold Water accompanied by nutrient supply seems to contribute to the high phytoplankton biomass at the front.

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.105-111
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• 2010

Caesalpinia sappan L. has long been commonly used in oriental folk medicines to treat diseases. To investigate the antibacterial effects from C. sappan L. heart wood, the MeOH soluble extract was successively fractionated by using hexane, $CHC1_3$, EtOAc, BuOH, MeOH, and $H_2O$. Among of these extracts, the EtOAc fraction which partitioned to 3.94% of the highest yields was to be the most active against all human pathogenic bacteria in this experiment. In addition, the antibacterial activities of the EtOAc fraction were more effective against Gram (+) bacteria compared to those against Gram (-) bacteria, which showed difference of the antibacterial activities against Gram (-) bacteria. To confirm the identity of the active substances, the EtOAc fraction was further separated by silica gel adsorption column, high performance liquid chromatography, and 98.48% purity of brazilin (1.67 mg)/EtOAc (10 mg) fraction was obtained from 300 g of C. sappan L. heart wood. The isolated active substance was a single compound of yellow crystalline, and was identified as brazilin ($C_{16}H_{14}O_5$) by MS, and $^lH$-NMR and $^{13}C$-NMR. These results suggest that the brazilin in the EtOAc fraction from MeOH extract of C. sappan L. has a potential as a natural therapeutic agent against human pathogenic Gram (+) bacteria such as Staphylococcus aureus.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.159-170
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• 2007

This study was focused on the investigation of the phytoplankton flora and community structure for changing of water environment at the rivers in the lower part of Nakdong river, The samples for this study were collected every month from Jan. 2004 To Dec. 2004. the 196 species belonged to 94 genera were identified during this study periods. The number of species was recorded the maximum 124 taxa in summer and the minimum 69 taxa in winter, We observed the maximum taxa (92 taxa) at the site No. 20 and the minimum taxa (55 taxa) at the site No. 8, respectively. Among the phytoplankton communities, diatoms were dominated over 40% of total phytoplankton groups. Subdominant groups were green algae (over 20% of total phytplankton groups). During this study periods, the 60 species were investigated ecologically significant species (46 cosmopolitic species, 25 pollution indicator, 21 redtide causative species, 8 dominant species, and 7 frequently occurred species). According to the cluster analysis by similarity index, the study sites could be divided into 4 groups.

• Korean Journal of Plant Resources
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• v.24 no.1
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• pp.40-47
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• 2011

Sphagnum palustre is a semi aquatic moss. S. palustre has been used as Korean traditional medicine to treat cardiac pain and stroke. This study was carried out to analyze phytochemical constituents of S. palustre and investigate the biological activity for the promotion of human health. At first, we isolated seven compounds from the ethanolic extract of this plant, and their structures were characterized by spectroscopic methods. Their structures were characterized to be Coumarin(1), Caffeic acid(2), Quercetin(3), Astragalin(4), Luteolin(5), Chlorogenic acid(6), Rutin(7) were for the first time reported from this source. The ethanol extract from S. palustre which was tested for its anticancer activity against three human tumor cell line by in vitro assay.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.147-153
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• 2018

There are few available studies for insect diversity in relation to coastal dune despite the unique landscape features and high conservation value. Therefore, this study compared ground beetle assemblages inhabiting between windbreak forests and sand dunes in the Taeanhaean National Park. It investigated five windbreak forests and three coastal dunes using pitfall traps from middle of June to middle of October in 2014. A total of 2,335 ground beetles belonging to 30 species of 15 genera were collected. Synuchus arcuarticollis (158 individuals) and Dolichus halensis halensis (153 individuals) were dominant of 25 specifies collected from sand dunes while Synuchus arcuarticollis (1,630 individuals), Synuchus nitidus (130 individuals), and Synuchus cycloderus (42 individuals) were dominant of 14 species collected from windbreak forests. The similarity of ground beetles compositions in sand dunes and windbreak forests was significantly low at 27.4%. The results of this study showed that sand dune geographical features found in the Taeanhaean National Park had different insect assemblages from windbreak forests. It will be the useful information for conservation of insects in the future.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.2
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• pp.151-159
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• 2018

In this study, we investigated the anti-oxidative activities and cell protective effects of the constituents isolated from S. aqueum branches. DPPH and $ABTS^+$ radical scavenging activities were screened for the ethanol extract and solvent fractions, ethyl acetate (EtOAc) and butanol (BuOH) fractions showed potent activities. When HaCaT cells were treated with $H_2O_2$, the ethanol extract and EtOAc fractions ($20{\mu}g/mL$) protected the cells against oxidative damage. Two constituents were isolated from the EtOAc fraction of S. aqueum branches; pinocembrin (1), desmethoxymatteucinol (2). The chemical structures of the isolated compounds were elucidated based on the spectroscopic data including $^1H$ and $^{13}C$ NMR spectra, as well as comparison of the data to the literature values. Anti-oxidative activities and cell protective effects were studied for the isolated compounds. For the anti-oxidative activities, all of the compounds 1 and 2 showed DPPH and $ABTS^+$ radical scavenging activities. Also, from the cell protective effect test, the compounds 1 and 2 protected the cell against oxidative stress by $H_2O_2$. Based on these results, S. aqueum branches extract could be potentially applicable as anti-oxidant ingredients in cosmetic industries.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.4
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• pp.289-295
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• 2017

A. koreanum was investigated to identify the constituents possessing whitening effects. As anti-melanogenesis activities were screened for the ethanol extract and solvent fractions, n-hexane (Hex) and ethyl acetate (EtOAc) fractions showed the most potent activities. Three constituents were isolated from the n-Hex fraction of A. koreanum; kaurenoic acid (1), $16{\alpha}$-hydro-17-isovaleroyloxy-ent-kauran-19-oicacid (2), $16{\alpha}$-hydroxy-17-isovaleroyl-oxy-ent-kauran-19-oic acid (3). The chemical structures of the isolated compounds were elucidated based on the spectroscopic data including $^1H$ and $^{13}C$ NMR spectra, as well as comparison of the data to the literature values. Whitening effects were studied for the isolated compounds. Upon the anti-melanogenesis test using ${\alpha}-MSH$ stimulated B16F10 melanoma cells, the compounds 1, 2 and 3 inhibited the cellular melanogenesis and intracellular tyrosinase activities effectively. Based on these results, A. koreanum stems extract could be potentially applicable as whitening ingredients in cosmetic formulations.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1654-1660
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• 1999

The free phenolic acid fraction of the chloroform extract from 75% ethanol extract of Rhus verniciflua STOKES (RCF) showed stronger antioxidative activity than BHT, BHA and ${\delta}-tocopherol$ at the same concentration. RCF components were isolated and identified by silica gel column chromatography, thin layer chromatography, mass spectrometer and $^1H-NMR\;and\;^{13}C-NMR$. The antioxidative activity was confirmed by electron donating activity, Rancimat method and thiobarbituric acid test in liposome system. RCF-11 could be further separated into three fractions. The antioxidative active compounds were purified and identified as gallic acid, butin and butein. The RCF-13 was purified and identified as sulfuretin.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.86-91
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• 2008

Dicamba(3,6-dichloro-2-methoxybenzoic acid) is used to control for pre and post-emergence of annual and perennial broad-leaf weeds. It is very soluble in water and highly mobile, acidic herbicide. So it is easily moved and detected in groundwater. Zerovalent iron(ZVI) has been used for the reductive degradation of certain compounds through amination of nitro-substituted compounds and dechlorination of chloro-substituted compounds. In this study, we investigated the potential of ZVI for the oxidative degradation of dicamba in water. The degradation rate of dicamba by ZVI was more rapidly increased in pH 3.0 than pH 5.0 solution. The degradation percentage of dicamba was increased with increasing amount of ZVI from 0.05% to 1.0%(w/v) and reached above 90% within 3 hours of reaction. As a result of identification by GC-MS after derivatization with diazomethane, we obtained three degradation products of dicamba by ZVI. They were identified 4-hydroxy dicamba or 5-hydroxy dicamba, 4,5-dihydroxy dicamba and 3,6-dichloro-2-methoxyphenol. 4-Hydroxy dicamba or 5-hydroxy dicamba and 4,5-dihydroxy dicamba are hydroxylation products of dicamba. 3,6-dichloro-2-methoxyphenol is hydroxyl group substituted compound instead of carboxyl group in dicamba. We also confirmed the same degradation products of dicamba in the Fenton reaction which is one of oxidation processes using ferric sulfate and hydrogen peroxide. But we could not find out the dechlorinated degradation products of dicamba by ZVI.