• Ocean and Polar Research
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• v.36 no.2
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• pp.121-134
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• 2014

Sessile marine bivalves including mussels, oysters and clams are often used as a sentinel species in coastal environmental monitoring since changes in the environmental quality are often well preserved in their tissues and shells. In this study, we investigated overall health condition of the Mediterranean Mussel, Mytilus galloprovincialis on the south coast using histology. Reproductive condition as gonad index (GI), condition index (CI) as a ratio of the tissue weight to the shell weight, digestive gland atrophy (DGA), types of parasites, and pathologic conditions including erosion, necrosis, hemocyte infiltration, and neoplasia were examined from each histological preparation. GI decreased from March to July then increased from July to September and spawning mussel could be observed as early as in April and the activity continued until September. CI also followed the monthly changes in GI, indicating that decrease in CI was associated with the weight loss due to spawning. DGA increased from March to June, decreased in July and increased from July to September. High DGA values observed in June and September were coincided with spawning and high water temperature. Histology also showed high prevalence of erosion in the digestive gland in June (36.0%) and September (56.4%), suggesting that high water temperature and spawning acted as environmental stressors. No parasitic organism was identified during the survey, although some symbiotic copepods were observed. Histology was found to be useful and affordable technique in monitoring the overall health of mussel, providing useful pathologic information of the cells and tissues.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.427-434
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• 2023

Oysters are an important organism, accounting for an average of 76% of shellfish aquaculture production. In this study, optimal habitat was searched for by calculating the Habitat Suitability Index (HSI) using water temperature, salinity, hydrodynamics, DO, SS and Chl.a in Jaran Bay. As a result, the inside of Jaran Bay was found to be a more suitable habitat than the outside with a wide entrance and rapid hydrodynamics. Oyster production and HSI showed a significant correlation (0.710, p<0.05). Hydrodynamics helps the growth of aquaculture organisms, such as food supply through seawater exchange in the bay, which showed a high correlation (0.709, p<0.05) with oyster production. It was found to have a greater effect on habitat suitability than Chl.a. The results of this study are expected to be helpful for the efficient conservation, use and management of coastal fisheries.

• Journal of the Korean Chemical Society
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• v.48 no.4
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• pp.394-398
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• 2004

From Sargassum thunbergii which is widely distributed in coastal area of Korea, three norisoprenoids, (+)-epiloliolide (1), (-)-loliolide (2), and apo-9'-fucoxanthinone (3) were isolated by using column chromatography and reverse-phase HPLC. Compound 1, 2 and 3 were for the first time isolated from the Brown Alga Sargassum thunbergii. Particularly, Compound 1 was for the first time isolated the marine organism although it was reported from the terrestrial plant. Their structures have been determined by extensive 2-D NMR experiments such as $^1H COSY, NOESY, HMQC$, and HMBC and by comparison with the reported data in the literature.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.31-32
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• 2005

Neoagaro-oligosaccharides are produced only by enzymatic degradation of agarose by ${\beta}-agarase.^{1)}$ Neoagaro-oligosaccharides inhibit the growth of bacteria, slow the rate of degradation of starch, are used as low-calorie additives to improve food quality, and have macrophage-stimulating activity. Furthermore, neoagarobiose is a rare reagent that has both moisturizing effect on skin and whitening effect on melanoma $cells.^{2)}$ An agar-degrading marine bacterium was isolated from the sea water at the northeast coast in Cheju island, Korea. The strain was gram negative, aerobic, and motile rod. The 16S rRNA of the strain had the closest match of 98% homology, with that from Agarivorans albus. On the basis of several phenotypic characters and a phylogenetic analysis, this strain was designated Agarivorans sp. JA-1. In solid agar plate, Agarivorans sp. JA-1 produced a diffusible agarase that caused agar softening around the colonies. Agarivorans sp. JA-1 was cultured for 36 hr in marine broth 2216 (Difco, USA) and the supernatant that containing an extracellular ${\beta}-agarase$ was prepared by centrifugation of culture media. The enzyme exhibited relatively strong activity at $40^{\circ}C$ and was stable up to $60^{\circ}C$. Using PCR primers derived from the ${\beta}-agarase$ gene of Vibrio sp., the gene encoding ${\beta}-agarase$ from Agarivorans sp. JA-1 was cloned and sequenced. The structural gene consists of 2931 bp encoding 976 amino acids with a predicted molecular weight of 107,360 Da. The deduced amino acid sequence showed 99% and 34% homology to $agaA^{2)}$ and $agaB^{2)}$ genes for ${\beta}-agarase$ from Vibrio sp., respectively. The expression plasmid for ${\beta}-agarase$ gene of Agarivorans sp. JA-1 is being constructed and the recombinant enzyme will be biochemically characterized.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.4
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• pp.214-220
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• 2008

The Ballast Water Management Convention provides that ballast water treatment systems which make use of active substances shall be approved from IMO according to the procedure developed by the IMO. The Convention described that active substance means a substance or organism, including a virus or a fungus, that has a general or specific action on or against harmful aquatic organisms and pathogens. The Marine Environment Protection Committee of IMO gave basic approval to 13 ballast water management systems and final approval to 4 systems until October 2008. This paper considered the matter of procedure and documents of the basic and final approval based on the "Procedure for approval of ballast water management systems that make use of Active Substances (G9)" and "The Methodology for information gathering and the conduct of work of the GESAMP-BWWG" and summarized the specifications of the treatment systems which was granted the basic or final approval from IMO and raised several points.

• Ocean and Polar Research
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• v.25 no.1
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• pp.31-40
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• 2003

In August-September 2001, 15 samples of bottom sediments were collected in the inner, middle and open parts of Amursky Bay near Vladivostok, Russia, and barfin plaice Pleuronectes pinnifasciatus was sampled from the inner and the middle locations of the bay. In the sediments from all three sites elevated concentrations of several heavy metals, i.e. Zn ($102-115{\mu}/g$ dry weight), Ni $(70-73{\mu}g/g)$ and Cu $(27-35{\mu}g/g)$ were discovered. The contents of oil hydrocarbons were very close to or slightly higher than the maximal normal environmental background level, $100{\mu}g/g$ dry weight. The sediments contained negligible amounts of hexachlorocyclohexane, while DDT concentrations were quite high (1.7-16.3ng/g dry weight). Generally, there were no substantial differences in the pollution levels of the locations studied and our results resembled those reported for Amursky Bay in the 1990s. Surprisingly, in 2001 'fiesh' DDT comprised 70-85% of the total DDT content in sediment from all the locations studied. In fish liver total DDTs concentrations were 212.8 and 122.54 ng/g wet weight for the inner and the middle locations, respectively, and 'fresh' DDT comprised 35 and 64% of DDTs, respectively. These results provide evidence of recent input of DDT from an unknown source into the ecosystem of Amursky Bay. Histopathological changes revealed in the plaice liver (vacuolization of hepatocytes, coagulative necrosis of hepatocytes, inflammatory reaction, and necrosis of epithelial cells of bile ducts) are probably connected with an intensive metabolism of DDT in the fish organism. No histological and histomorphometric differences were found in the state of the interrenal tissue. Similar condition of the liver and the interrenal tissue in barfin plaice sampled from the inner and the middle locations of Amursky Bay may be explained by the absence of great differences in the pollution levels of these sites.

• Molecular & Cellular Toxicology
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• v.2 no.2
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• pp.114-119
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• 2006

Benzo[a]pyrene is a representative ecotoxicant in marine environment and a model compound of polycyclic aromatic hydrocarbons, which has an ability to bioaccumulate in aquatic organisms. This study aimed to identify molecular biomarkers suitable for assessing environmental pollution using a microarray technique. We examined the effects of benzo[a]pyrene on gene expressions in the rockfish, Sebastes schlegeli. We constructed the subtractive cDNA library with hepatic RNA from benzo[a]pyrene-exposed and non-exposed control fish. From the library 10,000 candidate clones were selected randomly and cDNA microarray was constructed. We determined benzo[a]pyrene-responsive genes using a high-density microarray. Statistical analysis showed that approximately 400 genes are significantly induced or reduced by benzo[a]pyrene treatment ($2\;{\mu}m$). Especially gene expression changes of 4 candidate clones among the up- or down-regulated genes were investigated in 6, 12 and 24 hr BaP-exposed fish groups. Many methods have been developed to monitor marine environmental status, which depend on quantifying the levels of the toxic components in polluted seawater or on ecological accessing, such as species diversity or richness. However, those methods could not provide information on physiological or genetic changes induced by such environmental stresses. Comparing with the conventional methods, these data will propose that benzo[a]pyrene-responsive genes can be useful for biological risk assessment of polycyclic aromatic hydrocarbons on marine organism at molecular level.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.551-556
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• 2010

The large jellyfish Nemopilema nomurai causes serious damage to fisheries, particularly around the seas of Korea and Japan. Decreasing this damage requires knowledge of the distribution and abundance of jellyfish. Acoustic technology using quantitative echosounders is one method of studying the distribution and abundance of jellyfish. Such methods are commonly used worldwide because they have the advantage of providing substantial information about all water layers in a wide area in a short time. However, in order to conduct an acoustic survey, the acoustic characteristics of the target organism must be known. These can be altered by a number of factors, including pulsation, swimming angle, frequency and size. Accordingly, this study determined the variation in target strength according to pulsation of N. nomurai. Data were analyzed for two jellyfish with bell diameters in air of (a) was 32.0 and (b) 25.0 cm. The pulsation cycle of jellyfish (a) was 1.5~2.0 sec and the target strength (TS) cycle was 1.0~2.5 sec, while jellyfish (b) had a pulsation cycle of 1.0~1.5 sec and TS cycle of 1.0~3.0 sec. The variation width of the TS with the change in pulsation was 7.8 dB (-72.4~-64.6 dB) for jellyfish (a) and 10.3 dB (-71.6~-61.3 dB) for jellyfish (b). The variation in bell diameter was about 0.28 and 0.35, respectively. These results confirmed that the variation in bell diameter caused by pulsation is closely related to the variation in TS.

• Journal of Radiation Protection and Research
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• v.28 no.1
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• pp.75-78
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• 2003

The organically bound tritium(OBT) concentrations of the marine organisms(seaweed and shellfish) around Wolsung nuclear power plants were measured. The OBT concentrations of seaweeds were in the range of $0.372{\sim}2.72$ Bq/kg-fresh. The OBT concentrations of shellfish were in the range of $0.239{\sim}2.02$ Bq/kg-fresh. The internal dose due to the OBT concentration of seaweed was estimated as $3.4{\times}10^{-7}$ mSv/year.

• Journal of Life Science
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• v.13 no.6
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• pp.799-804
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• 2003

In order to verify the occurrence of an estrogenic compound in natural products, the estrogenic activity was measured using an in vitro detection system. For this system, human breast cancer cell line MCF7 was transfected using an estrogen responsive CAT reporter plasmid. Estrogenic activities of photosynthetic algae spirulina and sea lettuce were evaluated using this system. Estrogenic activities of a $500\mug/ml\; and\; 50 \mug/ml$ ethanol extracts of spirulina were as much as that of $10^{-8}$M standard solution (17$\beta$-estradiol) and activity of $5\mug/ml$ ethanol extract of spirulina was as much as that of $10^{-10}$ M standard solution. However, no significant estrogenic activity was observed using sea lettuce extract. Estrogenic activities of marine animals, such as star fish and shrimp, were also evaluated using this system, however, no significant estrogenic activity was observed in these extracts. In this result, it is confirmed that spirulina extract possesses estrogenic compound.