• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.214-222
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• 2007

This study was conducted to assay the relationship between the characteristics of watershed and water quality, and to evaluate water quality characteristics of the classified types by TSI deviation analysis with the collected data from 490 reservoir. Relatively shallow depth (<5m) reservoirs out of selected 490 appeared to be eutrophic. The mean TP concentration in reservoirs with the PFA+UFA/watershed area of above 30% was ${\geq}0.1$ mg $L^{-1}$. The mean TN concentration in reservoirs with the PFA/watershed area of above 25% was ${\geq}2.6$ mg $L^{-1}$. Based on the TSI deviation analysis, water quality parameters in TYPE III reservoirs were in high concentration compared to other reservoirs types. Characteristics of Type III generally showed eutrophic, small DA/RA ratio, shallow depth, and large paddy field and upland field to watershed ratio compared to other types of reservoirs. Both water quality and morpho-physical parameters, Type I and II reservoirs were similar with the exceptions of BOD and chi. ${\alpha}$ concentration. Phosphorus in Type I reservoirs was not the primary limiting factor on algal growth, but significant decrease chl. ${\alpha}$ concentration with the increasing TN/TP indicated that phosphorus was the possible secondary limiting factor. Overall results indicated that type of land use, such as PFA and UFA area in watershed, was important parameters for the assessment of water quality characteristics, and phosphorus was limiting nutrient on algal growth in 490 reservoirs.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.383-392
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• 2017

In 2013, August and September(early) as summer and October and November as Fall the probe of eutrophication has been done at 22 sampling points from the entrance of Danghang Bay (Jinhae Bay) to Geosan reservoir. In Danghang Bay, total chlorophyll(TChl) concentration of summer was 3.7 times higher than that of fall, and sampling points closer to the center showed 1.8 times higher concentrations than sampling points near the fringe where fresh water encountered. Eutrophication Index(EI) exceeded 1 at all sampling points in Danghang Bay during summer and fall, and if other conditions for algae growth met there was a possibility red tide to bloom at any place. There was a tendency of EI to gradually increase moving up from the entrance of bay to the inner side during summer and fall. Especially there was a sudden increase by 2.3 times higher at sampling points of 13~22 (planned region as Madong reservoir) than at other points during fall. Nitrogen was a limiting nutrient for growth of algae during summer and fall in Danghang Bay, but phosphorus was a limiting nutrient during summer rainy season. During summer and fall, multiple linear regression analysis between EI and COD, DIN, and DIP showed a significant positive relationship and that DIP was the most effective variable. Whereas multiple linear regression analysis between TChl and COD, DIN, DIP, and DSi showed a significant positive relationship and that DIP was also the most effective variable during summer. There was no significant correlation between TChl and the other parameters during fall.

• Journal of Life Science
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• v.18 no.12
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• pp.1671-1678
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• 2008

We investigated the effect of the turbid water on the phytoplankton community in the 4 sites of Imha reservoir. The turbidity of water was proportional to the concentrations of $SiO_2$-Si. Therefore, as the turbidity of water grow, the concentration of $SiO_2$-Si increased. And the both the turbidity of water and the concentrations of $SiO_2$-Si were increased as the water run deep. The concentration of chlorophyll-a decreased as the depth of water increased. Seventy phytoplankton taxa were identified and the most abundant group was Chlorophyceae consisting of 32 taxa (46%), and Cyanophyceae and Bacillariophyceae consisted of 12 taxa (17%). And Euglenophyceae, Synulophyceae, Cryptophyceae and Dinophyceae consisted of 6 taxa (9%), 4 taxa (6%), 3 taxa (4%) and 1 taxon (1%), respectively in Imha reservoir. The concentrations of phytoplankton were increased according to the turbidity of water because of the high amount of organic nutrition which is presented with turbid water. And especially, the concentrations of nitrogen increased easily because of the weak binding to the soil particle. In conclusion, total nitrogen and $SiO_2$-Si flowed into the Imha reservoir with soil particle, and these inorganic nutritions affect the growth of algae.

• Journal of Life Science
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• v.19 no.1
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• pp.75-80
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• 2009

Melanogenesis is a physiological process that results in the synthesis of melanin pigments. Tyrosinase is a key enzyme for melanin biosynthesis, and hyperpigmentation disorders are associated with abnormal accumulation of melanin pigments, which can be improved by treatment with depigmenting agents. Among the possible melanin-reducing compounds, tyrosinase inhibitors are most promising for preventing and treating pigmentation disorder and are used as skin-whitening agents in the cosmetic industry. In the present study, the effects of fucoidan on melanogenesis and tyrosinase activity of B16F10 melanoma cells were investigated. Melanin synthesis and tyrosinase activity in B16F10 melanoma cells were decreased in a dose-dependent manner by fucoidan. Melanin production and tyrosinase activity in B16F10 melanoma cells stimulated by a-melanocyte stimulating hormone (a-MSH) were inhibited by fucoidan with a dose-dependent manner compared to control. Fucoidan inhibited tyrosinase activity of B16F10 melanoma cells with a dose-dependent manner as assessed by 3,4-dihydroxyphenylalanine (DOPA) staining. In conclusion, these findings indicate that fucoidan, which inhibit melanin synthesis and tyrosinase activity, is an effective skin-whitening agent.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.18-24
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• 2013

The objective of study was to protect seabird breeding site and vegetation restoration of Chilbal and Sokugul island in Shinan county Jeonnam province, April and December 2011. We analyzed the soil properties according to the dominant communities and environmental gradient. As a result, It was highly analyzed to moisture content, organic matter, salinity, total nitrogen in Commelina communis community and low analyzed in Achyranthes japonica community. Carex boottiana community which mainly used as a seabird habitat has a wide range and Achyranthes japonica and Artemisia princeps community was narrowed to soil properties. Soil pH of Carex boottiana community in Sogugul island was the lowest on 3.14 and Peucedanum japonicum community was the highest. Soil moisture content and organic matter was analyzed by the high value in Peucedanum japonicum community. In contrast, Achyranthes japonica was the low value and Carex boottiana community was analyzed the highest on the salinity and total nitrogen. On the soil environmental characteristics according to the environmental gradient, The higher altitude, moisture content, organic matter, salinity and total nitrogen was the lower in Chilbal island. In the case of Sokugul island, the altitude difference did not show the characteristics of soil environmental factors for small area and low altitude. But moisture content is similar to soil property of Chilbal island. Soil property was strongly acid soil because of seabird dropping. This results will be helpful to manage the invasive plants.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.3
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• pp.163-168
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• 1976

Three species of Rhodophyceae namely Chondrus ocellatus, Grateloupia filicina and Gigartina tenella were collected from the coast of Haeundae, Busan, on June 33, 1975. And analysed with respect to the content of carrageenan and such chemical characteristics as the content of sulphate and 3, 6-anhydrogalactose, the solubility in potassium chloride solution. In addition, the same chemical properties were tested on the fractions separated by the different concentration of potassium chloride. Carrageenan content in Chondrus ocellatus was relatively higher than two other samples. All the samples showed more than thirty five percent. The Gigartina-carrageenan showed the highest 3,6-anhydrogalactose content among three samples of carrageenan obtained from different species, and the lowest marked from the Grateloupia-carrageenan. In comparison of the solubility of carrageenan in potassium chloride solution, the precipitation yields at 0.125M potassium chloride were marked in order of Chondrus-carrageenan, Grateloupia-carrageenan, and Gigartina-carrageenan, and the yields at 0.125 M to 2.0 M potassium chloride were in Gigartina-carrageenan, Grateloupia-carrageenan, and Chondrus-carrageenan, and the yields from the soluble fraction at 2.0 M potassium chloride were in order of Grateloupia-carrageenan, Gigartina-carrageenan, and Chondrus-carrageenan. It is noteworthy from the result of characteristics of carrageenans that, 3,6-andydrogalactose content was closely related to the solubility of carrageenans in potassium chloride solution and to the sulphate content which might affect reversibly.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.75-84
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• 2009

The effect of various SNPs (silver nanoparticles) on the growth of Microcystis aeruginosa was investigated in laboratory and field experiment. Four SNPs, namely JS47N, JS47N-K2, JS47N/3-1 and JS47N/3-2 were used to this study. The Ag size, concentration and color of these solutions were about $20{\sim}40nm$, $200mg\;L^-1$ and brown, respectively. At 0.01 and $0.1mg\;L^-1$, SNPs inhibited the growth of unicellular M. aeruginosa by 99.4% and 99.9%, respectively. However, SNPs of $1mg\;L^-1$ inhibited the growth of colonial M. aeruginosa by 98.5%, whereas the other three concentrations (0.001, 0.01 and $0.1mg\;L^-1$) had little inhibitory effect. In experimental enclosures from eutrophic lake, cyanobacteria including M. aeruginosa were found to be more sensitive to the SNPs than green algae and diatoms. In conclusion, our study indicates that SNPs has a selective cyanocidal potential when used to M. aeruginosa. We believe that future studies need to test on various other organisms, and determine minimum concentration for field application.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.290-300
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• 2022

A strain of Alexandrium species was established by isolating cells from Jangmok Bay, Korea. Its morphology and molecular phylogeny based on LSU rRNA gene sequences were examined. In addition, growth responses of this Alexandrium species to changes in temperature, salinity, and nutrient concentrations were investigated. This Alexandrium species from Jangmok Bay had a ventral pore on the 1', which was morphologically consistent with previously described Alexandrium tamarense and A. catenella. Phylogenetic analyses revealed that this isolate was assigned to A. pacificum (Group IV) within A. tamarense species complex. In growth experiments, relatively high growth rates and cell densities of A. pacificum (Group IV) were observed at 15℃ and 20℃. This species also grew under a wide range of salinity. This indicates that this Korean isolate of A. pacificum (Group IV) is a stenothermic and euryhaline species. In growth responses to changes in nutrient levels, enhanced growth rates and cell densities of A. pacificum(Group IV) were observed with additions of nitrate and phosphate. In particular, rapid uptakes of phosphate by A. pacificum (Group IV) were observed in experimental treatments, indicating that the increase in phosphate concentration could stimulate the growth of A. pacificum(Group IV).

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.542-546
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• 2018

In this study, the effects of malonic acid-catalyzed pretreatment on the subsequent enzymatic hydrolysis of red macro-algae Gracilaria verrucosa for production of biosugar (total reducing sugar) were investigated. In the hydrothermal pretreatment condition of 300 mM malonic acid, 1:20 solid-to-liquid ratio at $130^{\circ}C$ for 60 min, a 49.2% biosugar yield was achieved. Moreover, by subsequent enzymatic hydrolysis after pretreatment, maximum yield of 64.5% was achieved.

• Korean Journal of Environmental Biology
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• v.19 no.2
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• pp.107-112
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• 2001

A tissue biosensor was developed for the continuous determination of $Na^+$ channel blockers. The proposed sensor was applied to the determination of Na+ channel blockers in seaweed. It was found that $Na^+$ channel blocker content displayed seasonal variation; it was high from February to April and decreased thereafter (May - August). From these results the present proposed method may be used for high sensitive determination of $Na^+$ channel blockers contained in the seaweed organisms and environments. Therefore, it may be important to monitor $Na^+$ channel blocker content of seaweed throughout the year.