• Journal of fish pathology
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• v.27 no.1
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• pp.57-65
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• 2014

Copper ($CuSO_4$) has been widely used to control algae and pathogens in fish culture ponds. However, its toxic effects on fish depend not only on its concentration in water but also on water quality. The susceptibility of the rockfish, Sebastes schlegeli to copper was evaluated at three water-temperatures (WT; 18, 23 and $28^{\circ}C$) for 4 days. After the exposure of two copper concentrations (100 and $200{\mu}g/L$), a hematological effect was exerted on rockfish, by causing changes in red blood cell count and hematocrit value at $28^{\circ}C$. Total protein levels of the fish showed a tendency of co-increase with glucose depend on the WT, after copper exposure. However, the plasma calcium and magnesium levels were significantly increased at $200{\mu}g/L$ copper, regardless of the WT. Enzymes activities including ALT and LDH in serum were also significantly increased depend upon the copper treatment only. This indicates that inorganic components and enzymes activities were sensitive indexes to stress by toxicant such as copper. The cortisol levels were significantly elevated by both WT rising and copper treatment in serum of rock fish. In conclusion, these changes can be seen as an initial response to temperature stress and as a sustaining response to copper exposure. The present findings suggest that a simultaneous stress by temperature change and copper exposure could accelerate an alteration of hematological and plasma biological parameters in the rockfish.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.1
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• pp.9-15
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• 2012

Worldwide development of harmful algal blooms causes serious problem for public health and fisheries industries. To evaluate the algicidal impact on the harmful algae bloom species in aquatic ecosystems of coast, a new algicide thiazolidinedione derivative (TD49) were tentatively examined in the growth stages (i.e., lag, logarithmic and stationary phase) of rapidophyceae $Heterosigma$ $akashiwo$, $Chattonella$ $marina$ and $Chattonella$ sp..Three strains could easily destroy in the lag phase due to relatively weak cell walls than those of the logarithmic and stationary phase. It is thought that inoculation of TD49 substances into initial or developmental natural blooms with a threshold concentration ($2{\mu}M$) can maximize the algicidal activity. Also, bio-chemical assays revealed that the algicidal substances from all culture strains were likely to be extracellular substances because those cells have easily destroyed in cell walls. On the other hand, natural zooplankton communities were influenced within the exposure experiments of $2{\mu}M$, which is showed the maximum algcidal activity of tested organisms. These results indicate that although the TD49 substance is potential agents for the control of $H.$ $akashiwo$, $C.$ $marina$ and $Chattonella$ sp. in the enclosed eutrophic bay and coastal water, more detailed research of acute toxicity effect on high trophic organism in marine ecosystems need to be conducted.

• Ocean and Polar Research
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• v.25 no.4
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• pp.427-435
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• 2003

Growth and pigment responses to different levels of solar radiation with or without ultraviolet (UV)-B component $({\lambda}=280-315nm)$ were investigated in Antarctic rhodophytes, Kallymenia antarctica and Palmaria decipiens, collected around King George Island during the summer of 2000. In K. antarctica specific growth rate, based on thallus area or fresh weight, decreased with increasing solar irradiances while P. decipiens were relatively insensitive to the effects of light. It is noticeable that the presence or absence of UV-B had no significant effect on growth for either species. However, K. antarctica showed a more pronounced reduction in chlorophyll (Chl a) concentrations at higher irradiances in the presence of UV-B. In P. decipiens, Chl a concentrations did not differ despite radiation level fluctuations being lower albeit than initial measurements. Thallus thickness was greater in K. antarctica than in P. decipiens. There were higher relative amounts of UV-absorbing pigments (UVAPs) in P. decipiens than in K, antarctica. The single absorbance peak obtained from the methanol extracts was resolved into three (316,332 and 346nm) in K. antarctica and four peaks (315,326,333 and 349 nm) in Palmaria as a result of the fourth-derivative. After 7 days exposure to solar radiation, the amount of UVAPs in K. antarctica was significantly reduced to a similar degree at all light levels, whereas that of P. decipiens remained unchanged except at 5% of surface irradiance. High performance liquid chromatography (HPLC) analysis of purified extracts indicated that P. decipiens possesses porphyra-334 in addition to three other mycosporine-like anlino acids (MAAs; asterina-330, palythine, shinorine), which are commonly present in K. antarctica. Significantly lower tolerance of K. antarctica to high levels of solar radiation may be connected with its usual absence in the eulittoral, while the active growth and elastic pigment responses of P. decipiens over a wide range of solar irradiance levels up to full sunlight seems to correspond well with its wide vertical distribution from rock pools down to 25-30m.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.1-9
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• 1999

Numerous observations revealed strong evidence of increased middle ultraviolet radiation or UV-B (280 ~ 320 nm) at the earth's surface resulting from stratospheric ozone depletion. UV is the waveband of electromagnetic radiation which is strongly absorbed by nucleic acids and proteins, thus causing damage to living systems. It has been recorded in the East Sea, Korea that solar UV-B impinging on the ocean surface penetrates seawater to significant depths. Recent researches showed that exposure to UV-B for as short as 2h at the ambient level (2.0 Wm$^{-2}$) decreased macroalgal growth and photosynthesis and destroyed photosynthetic pigments. These may suggest that UV-B could be an important environmental factor to determine algal survival and distribution. Some adaptive mechanisms to protect macroalgae from UV-damage have been found, which include photoreactivation and formation of UV-absorbing pigments. Post-illumination of visible light mitigated UV-induced damage in laminarian young sporophytes with blue the most effective waveband. The existence of UV-B absorbing pigments has been recognized in the green alga, Ulva pertusa and the red alga, Pachymeniopsis sp., which is likely to exert protective function for photosynthetic pigments inside the thalli from UV-damage. Further studies are however needed to confirm that these mechanisms are of general occurrence in seaweeds. Macroalgae together with phytoplankton are the primary producers to incorporate about 100 Gt of carbons per year, and provide half of the total biomass on the earth. UV-driven reduction in macroalgal biomass, if any, would therefore cause deleterious effects on marine ecosystem. The ultimate impacts of increasing UV-B flux due to ozone destruction are still unknown, but the impression from UV studies made so far seems to highlight the importance of setting up long-term monitoring system for us to be able to predict and detect the onset of large -scale deterioration in aquatic ecosystem.

• Food Science and Preservation
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• v.21 no.5
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• pp.652-660
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• 2014

To maintain the microbiological safety of Prunus mume fruit before it is processed, it was treated with a combination of 0.5% citric acid and 0.1% Tween 20, and stored at $4{\pm}1^{\circ}C$ for seven days. The combined treatment reduced total aerobic bacteria, yeast, and mold populations in the fruit by 2.20 and 1.70 log CFU/g, respectively, compared to those in the control. Organic acid contents and the Hunter $L^*$, $a^*$, and $b^*$ values were not affected by the treatment during the storage. In addition, the dried Prunus mume fruit prepared with 40% red algae extract (RAE) or maltodextrin (MD) treatment and hot-air drying were compared with respect to the fruit's physicochemical properties such as color, total phenolic and flavonoid content, and microstructure. The hot-air dried samples had undesirable color changes and inferior textures. The RAE-treated samples had a higher total phenolic content (225.15 mg gallic acid equivalent (GAE)/100 g) and total flavonoid content (49.25 mg quercetin equivalent (QE)/100 g) than the other treatments. The treatment of Prunus mume fruit with RAE can provide better-dried products than can MD treatment or hot-air drying. These results suggest that the combined treatment with citric acid and Tween 20 can be effective in preserving the microbiological safety of Prunus mume fruit, and its dehydration using RAE is an efficient drying method.

• Food Science and Preservation
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• v.24 no.5
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• pp.673-679
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• 2017

In this study, the antimicrobial, antioxidant activities and ${\alpha}$-glucosidase inhibitory activities of Amphidinium carterae ethanol extract (AE) was evaluated for using as a functional food ingredient. Chlorella ethanol extract (CE) was used to the comparison as a control. Anticancer activities of the AE and CE were analyzed by HepG2 and HT-29 human cancer cell. The AE showed antimicrobial activities for all tested bacterial strains. Whereas, CE showed antimicrobial activities for several tested bacterial strains only. The CE showed higher total phenolics contents, DPPH and ABTS radical-scavenging activities (47.36 mg/g, 22.42% and 28.58%, respectively) than those of AE (8.88 mg/g, 20.16% and 17.69%, respectively). AE showed anti-diabetic effect on ${\alpha}$-glucosidase inhibitory activity with dose-dependantly manner. The cell viability of AE ($125{\mu}g/mL$) on HepG2 and HT-29 human cancer cells were 38.12% and 11.27%, respectively. It was demonstrated that ethanol was efficient solvent for extracting functional components from A. carterae. These results indicated that AE can be described as a good candidate for using as a functional food ingredient.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.438-442
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• 2013

The study of bioproduct production from inexpensive biomass such as marine biomass has recently attracted considerable attention. Because, marine biomass which compared to land biomass, it can be grown rapidly and is easily cultivated without the need for expensive equipment. In addition, the carbohydrate contents are similar or higher than land biomass such as woody biomass and can be easily converted to chemicals through proper chemical processes. In the production of various biochemicals from marine biomass, levulinic acid is a highly versatile chemical with numerous industrial uses and has the potential to become a commodity chemical. It can be used as a raw material for resins, plasticizers, textiles, animal feed, coatings and antifreeze. In this study, experiments were carried out to determine the optimum conditions of temperature, acid concentration and reaction time for production of levulinic acid from marine biomass, Gelidium amansii, using two-step treatment. In the first hydrolysis step, solid-state cellulose which was used to produce ethanol by fermentation and liquid-state galactose which used to produce bioproduct such as levulinic aicd were obtained through acid soaking. In the second hydrolysis step, the liquid-state galactose was converted into levulinic acid via a high-temperature reaction in a batch reactor. As a result, the overall production yield of Gelidium amansii to levulinic acid in the two-step acid hydrolysis was approximately 20.6% on the initial biomass basis.

• Korean Journal of Environment and Ecology
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• v.28 no.6
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• pp.613-626
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• 2014

Seaweeds were identified after qualitative sampling at 14 stations of Dokdo coasts from May to July 2013 and seaweeds and animals inhabiting 23 Eisenia bicyclis plants were examined to evaluate its ecological role. Biomass was calculated by using regression between stipe length and weight of E. bicyclis. A total of 128 species were identified, including 18 green, 35 brown, and 75 red algae. Coarsely branched form was dominant functional group occupying 47.66% and 91 species (71.09%) were in ESG I group, growing in stable environmental coast. Also, R/P, C/P, and (R+C)/P were 2.14, 0.51, and 2.66, respectively showing temperate and mixed flora. Biomass and density of E.bicyclis were $23.74kg\;m^{-2}$ and 64 fronds $m^{-2}$. Twelve seaweeds and 83 animal species (15 Annelida, 25 Mollusca, 34 Arthropoda, 3 Echinodermata, and 6 others) were observed from 23 holdfasts and Ericthonius pugnax was dominant taxon having 538 (43.11%) of 1,248 animal individuals. These results indicate that E.bicyclis is a keystone species showing very important ecological role. In conclusion, the number of seaweeds increased because of intensive research and dominance of coarsely branched form and ESG I group seaweeds, representing that environmental condition of Dokdo is still intact.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.595-603
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• 2017

The macroalgal community structure was examined at the subtidal zones of six study sites, on the Southern coast of Korea from between May and August 2015. A total of 132 seaweeds, comprising 10 green, 28 brown and 94 red Seaweed, were identified. The seaweed biomass was $80.32g\;dry\;wt.\;m^{-2}$ in average, and it was maximal at Geomundo ($166.94g\;dry\;wt.\;m^{-2}$) and minimal at Byeongpungdo ($14.52g\;dry\;wt.\;m^{-2}$). On the basis of the biomass, the Ecklonia cava was a representative species, distributed widely in the subtidal zone of the three islands (Yeoseodo, Geomundo, Baekdo). Also, the Sargassum sp. was dominant at Sejondo and Hongdo. The turbidity and light transmittance was divided into two groups. The seaweed community structure of group A (Byeongpungdo, Sejondo, Geomundo) was characterized by high turbidity, low light transmittance and a lower habitat depth than were observed in group B (Hongdo, Baekdo, Yeoseodo). As the water depth increased, the biomass decreased due to the lowered light transmittance. In Byeongpungdo and Sejondo, which showed high turbidity and low light transmittance, the degree of seaweed coverage was decreased with the depth of water. The ESGII ratio of the Ecological Status Group was higher than fourty percentage in Byeongpungdo and Baekdo. Community indices were as follows: dominance index (DI) 0.35-0.90, richness index (R) 7.03-17.93, evenness index (J′) 0.22-0.60, and diversity index (H′) 0.79-2.18. The Macroalgal zonation of the subtidal zone was calculated by the Ecklonia cava and Brown algal population on five islands(Byeongpungdo, Yeoseodo, Geomundo, Beakdo, Hongdo). On the other hand, Undaria pinnatifida and Sargassum sp. dominated at Sejondo. Additionally, the biomass ratio and the species richness of green algae was lower in group A. These differences in the seaweed community structure may have resulted from the effects of turbidity and light transmittance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.495-500
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• 1999

The carrageenans are linear, sulfated Polysaccharides extracted from various species of the Rhodophyta (marine red algae). The carrageenan backbone is based on a repeating disaccharide sequence of $\beta$-D-galactopyranose residues linked glycosidically through position 1 and 3, and $\alpha$-D-galactopyranose residues linked glycosidically through position 1 and 4. Carrageenans are typical food polysaccharides in that food applications overwhelmingly dominate their end uses. Other applications, hewer, including cosmetics, pharmaceuticals, industrial suspensions and paints are also of importance But because of its high degree of gelling and viscosity with low solubility, carrageenan is limited to use beyond $0.03\%$ as food additives. Response Surface Methodology was applied for optimizing the processing parameters of ultrasound treatment in order to produce low-molecular-weight carrageenan. The use of ultrasound significantly reduced viscosity of $\lambda$-carrageenan solutions. Optimal parameters for ultrasound reduction of carrageenan molecular weight were: temperature, $10^{\circ}C$; ultrasound intensity, 121.64 $W/cm^2$ ; tarrageenan concentration, $2\%$; treatment time, 40 min. As the gel permeation chromatogram of dextran standards (M.W.= 500,000 ; 260,000 ; 167,000 ; 71,400 ; 42,000) and ultrsound treated carrageenan, the molecular weight of ultrasound treated carrageenan were approximately 200,000 (peak 1) and 60,000 (peak 2), respectively.