• Journal of Life Science
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• v.20 no.8
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• pp.1201-1206
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• 2010

We performed a comparative analysis using a Real-time PCR (Polymerase Chain Reaction) and LC/MS (Liquid-Chromatograph/Mass Spectrometer) method in order to detect microcystin in environmental sources. Among the three different primer sets tested for microcystin using three positive strains of Microcystis aeruginosa by Real-time PCR assay, only TOX2P/TOX2M primer pairs were able to detect Microcystis aeruginosa. According to the results of a survey carried out from June 2009 to September 2009, 11 out of 11 (100%) raw water samples were were found to have microcystin when the Real-Time PCR and LC/MS method was used, with total microcystin concentration ranging from 5.98~219.0 ${\mu}g/l$. A microcystin removal treatment process was used to ensure entire removal, by passing it through a BAC filtration step. It was concluded that real-time PCR assay can be used to estimate micrucystin detection more rapidly and easily than the LC/MS method.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.2
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• pp.78-86
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• 1997

To clarify the phytoplankton blooms in Lake Shihwa after the construction of a dyke, a study on the environmental factors, the distribution of chlorophyll-a, phytoplankton standing stocks, dominant species and primary productivity was carried out in Lake Shihwa and adjacent coastal areas from October, 1995 to August, 1996. Lake Shihwa is brackish water with mixing of freshwater from tributaries and the remaining salt water at the bottom. The dense phytoplankton bloom of average value of 168.6 ${\mu}gChl-a\;l^{-1}$ have occurred throughout the year in Lake Shihwa which is eutrophicated by the large input of nutrients from inflowing 5 tributaries and Shihwa Industrial Complex. The major organisms of algal bloom in Lake Shihwa were diatoms, Cyclotella atomus, Nitzschia sp. and Chaetoceros sp. in autumn and winter, and dinoflagellate Prorocentrum minimum and Chrysophyceae in spring and summer. The autumn and winter diatom blooms were limited by the depletion of silicate in the lake. Diatom blooms have occurred in the coastal areas adjacent to Shihwa lake from winter to summer due to the inflow of nutrient rich-water from Lake Shihwa. The primary productivities in the Lake Shihwa ranged from 2,653 mgC $m^{-2}\;day^{-1}$ to 9,505 mgC $m^{-2}\;day^{-1}$ with an average of 3,972 mgC $m^{-2}\;day^{-1}$. However, most of the high primary production was limited to the shallow euphotic zone due to the inhibition of light penetration. The primary productivities during autumn and winter were limited by the depletion of silicate. Lack of photosynthesis and the decomposition of falling organic matter under the middle of water column accelerated the depletion of dissolved oxygen in the bottom layer.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.265-275
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• 2013

Variances in environmental factors were followed in Ilwol reservoir, Suwon, during bloom of Microcystis aeruginosa (K$\ddot{u}$tzing) K$\ddot{u}$tzing, Cyanophtya from August to October, 2011. M. aeruginosa dominated the water column throughout the investigation period. The water temperature varied from $25.7^{\circ}C$ to $28.4^{\circ}C$, pH 8.40 to 11.17, CODcr 4.25 to $72.00mg\;L^{-1}$, electrical conductivity 333.1 to $749.0{\mu}g\;cm^{-1}$, and Chl-a 22 to $185mg\;L^{-1}$. In particular, the high levels of CODcr is likely indicate high contribution of autochthonous organic matters in the reservoir. TN varied from 28.86 to $56.75mg\;L^{-1}$, TP 0.20 to $1.24mg\;L^{-1}$, Fe 0.11 to $1.05mg\;L^{-1}$, and Si 3.13 to $7.46mg\;L^{-1}$. These increases imply constant accumulation in Ilwol reservior, and reinforce the idea of autochthonous organic matters input in the reservoir. The Korea Trophic Status Index ($TSI_KO$) varied from 37.19 to 147.22. Trophic levels varied from mesotrophic to hypertrophic level, and differed spatio-temporally. Therefore, it is concluded that $TSI_KO$ is useful for analyzing trophic status of reservoirs.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.2
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• pp.52-57
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• 2015

The purpose of this study was to investigate a relationship between ultraviolet radiation and initial cell density (ICD) of microalgae using a floating marine photobioreactor (PBR). To examine the effect of ultraviolet (UV) radiation in sunlight on biomass productivity as a function of ICD, 0.5-L floating PBRs covered with or without UV cut-off film were placed in an outdoor rectangular tank containing 200 L of water. At the lower ICDs, 0.01 and 0.05 g/L, biomass productivities in the PBRs without UV cut-off film decreased by $278{\pm}21%$ and $222{\pm}3%$ compared with those with the film, respectively. In contrast, the presence of UV cut-off film did not have a significant effect on biomass productivities at the higher ICDs, 0.25 and 1.25 g/L. When the differences in biomass productivity made by the UV cut-off film were plotted against the sum of cell projection area per light receiving area of the PBR, the results revealed that the inhibitory effect of UV on biomass productivity can be negligible when the sum of cell projection area is equal to the light receiving area of the PBR. These results show that photoinhibition caused by UV radiation could be eliminated via operating the PBR with a proper ICD.

• Journal of Life Science
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• v.19 no.10
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• pp.1396-1402
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• 2009

Hizikia fusiforme is a kind of edible brown seaweed that grows mainly in the northwest Pacific including Korea, Japan and China, and has been widely used as food in Korea. Induction of cyclooxygenase-2 (COX-2) expression and prostaglandin $E_2$ ($PGE_2$) production is thought to have beneficial immunomodulatory effects in acute and chronic inflammatory disorders. In this study, we investigated the effects of extracts of H. fusiforme on the expression of COX-2 and production of $PGE_2$ in U937 human pre-monocytic cell models. In U937 cells stimulated with phorbol 12-myristate 13-acetate (PMA) to mimic inflammation, methanol extract of H. fusiforme (MEHF) and ethanol extract of H. fusiforme (EEHF), but not water extract of H. fusiforme (WEHF), inhibited PMA-induced expression of both COX-2 protein and mRNA, which was associated with inhibition of $PGE_2$ production. To investigate the mechanism by which MEHF and EEHF inhibit COX-2 gene expression and $PGE_2$ production, we examined the activation of nuclear factor-kappaB (NF-$\kappa$B) in U937 cells. Pre-treatment with MEHF and EEHF significantly attenuated the PMA-induced IkappaB degradation and prevented nuclear translocation of NF-$\kappa$B. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-inflammatory activity of H. fusiforme.

• The Korean Journal of Food And Nutrition
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• v.19 no.2
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• pp.169-175
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• 2006

A unicellular algae, Chlorella vulgaris(CV), was used as a biological response modifier. The effect of CV on forced swimming test and blood biochemical parameters related to fatigue was investigated. Blood urea nitrogen(BUN); creatine kinase(CK); lactic dehydrogenase(LDH); glucose(Glc); total protein(TP); and albumin were determined. CV was orally administered to mice in the range of 0.05 to 0.15 g/kg/day. A forced swimming test results on 3 and 7 day after administration of CV, showed that immobility time was decreased in the CV-administered group(0.15 g/kg). In addition, the contents of BUN in the blood serum were decreased in CV-fed group. The contents of CK and LDH were tended to decrease, but not statistically significant. The plasma Glc level was increased in CV-fed groups(0.05 and 0.1 g/kg) compared to control group. It had no effect on the elevation of TP and albumin level. The results indicate that CV could improve physical stamina.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.6
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• pp.663-669
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• 2007

The solvent extracts of Sargassum muticum, which were extracted by using several solvents with different polarities, were prepared for use as natural preservatives. The S. muticum extract with 80% ethanol was sequentially fractionated with n.hexane, dichloromethane, ethylacetate, and butanol. In order to effectively screen for natural preservatives agents, we first investigated the antioxidant activities such as DPPH radical scavenging capacity, superoxide radical scavenging capacity, and xanthine oxidase inhibitory activity of the S. muticum extracts. Through the screening system, we found that dichloromethane and ethylacetate fraction had high antioxidant activity with increments of the extract concentration. The antimicrobial activities and cell growth inhibition were investigated for each strain with the different concentrations of S. muticum extracts. Antimicrobial activities were shown in ethanol, dichloromethane, and n.hexane fractions of S. muticum. However, butanol, ethylacetate and water fractions showed weak antimicrobial activity against the tested microorganisms. Among the five fractions, dichloromethane fraction showed the highest antimicrobial activities against microorganisms tested, such as Bacillus sublitis, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella Enteritidis and Pseudomonas aeruginosa. The polyphenolic compounds from ethanol, n.hexane, dichloromethane, ethylacetate, butanol, and water fractions were 63.96 mg/g, 8.49 mg/g, 28.11 mg/g, 172.64 mg/g, 114.56 mg/g, and 34.91 mg/g, respectively. The dichloromethane fraction could be suitable for development as a food preservative.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.335-346
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• 2005

In this study, core sediments and pore water were analysed to identify the origin of organic matter and Bas in late Quaternary sediments from the northwestern Ulleung Basin of the East Sea. C/N and C/S ratios in the sediments show that the organic matter in the study area originated predominantly from marine algae. However, the results of Rock-Eval pyrolysis indicate that the organic matter has an origin of the land-plant (Type III), locating in the immature stage. These different results might be due to the heavy oxidizing of the organic matter during sinking down to the seafloor or after deposition in the sediments. Concentration of sulfate in the pore water decreases gradually with core depth, while concentration of $CH_4$ increases gradually with core depth. This indicates that sulfate reduction and methanogenesis occurred actively in the sediments. Also, it is likely that the compositions of $CH_4$ are characterized as a more biogenic origin, mostly caused by microbial activity, rather than a thermogenic one.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.317-330
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• 2009

To diminish the levels of organic matters, a novel S-CROM (continuous removal of organic matters in the stream system using freshwater bivalve), was developed and applied to the polluted stream discharging from the wastewater treatment plant, Pocheon stream, Pocheon city (Korea). Major pollutants of the stream were human population and industrial wastewaters. The study was conducted at a small dam constructed within the stream, often called 'bo', and designed with four tanks; no mussels and no sediment (negative control), no mussels and sediment (positive control), 30 mussels and sediment (D1), and 60 mussels and sediment (D2). Physicochemical and biological parameters were measured at 12 hours interval (day and night) after mussel stocking. Results indicated that Anodonta woodiana Lea (D2) clearly removed approximately 72% of chl-$\alpha$ and 57% of suspended solids on second day, however, there were no differences in removal activities between animal densities (P>0.5). Dislike a laboratory CROM system, which previously developed, there were no huge release of nutrient ($NH_3$-N and SRP), due perhaps to the higher flow rate and the lower animal density. Therefore, we may suggest that if we can determine the relevant current and the animal density considering the stream state, an S-CROM system has a strong potential to water quality improvement of eutrophic streams. Some characteristics on both CROM and S-CROM were compared.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.404-406
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• 2009

This study note wished to introduce special-purpose ship for algae removal that is developed by core technology of our country. The ship is consisted of main frame and adjuvant that can attach and detach as cross (+) shape of a character. The characteristics of ship are super light weight and low draft. That is consisted of four devices as suction, collection, filtration and recovering units. Among these, filtration used screen filter (mesh size 30 ${\mu}m$). Also, can separate and remove water and algae by compression air participle notion. Percentage of moisture content of concentrated algal particle was 85%. Water parted with algae finally is exhausted to water area. Removal efficiency that compare by chlorophyll-$\alpha$ concentration was about 57% (inflow: 83.2 ${\mu}g\;L^{-1}$, outflow: 35.8 $[\mu}g\;L^{-1}$) without physical and chemical pretreatment. Forward, need to achieve effect test in various conditions (algal biomass, flow etc.) for efficiency and technological elevation of exclusion device. We wished to contribute in presuppression system construction of massive algal development that manage blue-green algae occurrence area effectively, and prevents spread as lower part of reservoir.