• 한국패류학회지
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• 제30권4호
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• pp.443-447
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• 2014

Triploids have several potential advantages over diploids in aquaculture, drawing an elevated commercial reaction into the realistic application of the techniques despite we are still in the early stage of triploid industry for the Pacific oysters Crassostrea gigas. We traced the growth performance of the triploid C. gigas for over a year from hatchery spats, which was created by manipulations of chemicals (Cytochalasin B, CB or 6-Dimethylaminopurine, 6-DMAP). The growth was clearly marked by an initial longer dormancy and following a great magnitude of heterogeneity. The dormancy was almost 9 to 10-month long or even longer and was considered as a downside of the creation. The heterogeneity was magnified by appearance of extraordinarily growing oysters in part during summer season, which could be a representative upside of the triploids. Overall, however, the results were not as positive as were expected. The longer dormancy and following heterogeneity observed in our practice could be marked as an additional negative sign of the chemical use. The present study, thus, might be highly indicative in the introduction of biological cross between tetraploid and diploid to produce natural triploid embryos.

• 한국양식학회지
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• 제20권4호
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• pp.205-211
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• 2007

Stress-inducible proteins may function in part as molecular chaperones, protecting cells from damage due to various stresses and helping to maintain homeostasis. We examined the mRNA expression patterns of a 68-kDa heat shock protein (HSP68) and 78-kDa glucose-regulated protein (GRP78) in relation to physiological changes in Pacific oyster Crassostrea gigas under osmotic stress. Expression of HSP68 and GRP78 mRNA in the gill significantly increased until 48 h in a hypersaline environment (HRE) and 72 h in a hyposaline environment (HOE), and then decreased. Osmolality and the concentrations of $Na^+$, $Cl^-$, and $Ca^{2+}$ in the hemolymph of HRE oysters significantly increased until 72 h (the highest value) and then gradually decreased; in HOE oysters, these values significantly decreased until 72 h (the lowest value), and then increased. These results suggest that osmolality and $Na^+$, $Cl^-$, and $Ca^{2+}$ concentrations were stabilized by HSP68 and GRP78, and indicate that these two stress-induced proteins play an important role in regulating the metabolism and protecting the cells of the Pacific oysters exposed to salinity changes.

• 한국수산과학회지
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• 제25권6호
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• pp.485-494
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• 1992

1985-1989년간 한국연안의 서로 다른 서식지로부터 채집된 진주담치 Mytilus edulis와 굴 Crassostrea gigas중의 중금속 농도를 알아보았다. 두이매패류에서 가장 높은 중금속농도는 조사점 1, 2, 5, 23 그리고 25에서 발견되었던 반면 가장 낮은 중금속농도는 진해만 주위의 조사점에서 발견되었다. 5개년간 굴과 진주담치의 평균중금속농도비는 Cu 16:1, Cd 1.63:1, Pb 1.36:1, Zn 7.61:1 그리고 Hg 2.08:1로서 굴이 진주담치보다 Cu, Zn, Hg에서 보다 효과적인 생물농축자로 나타났다. 진주담치의 크기별 분포는 크기가 클수록 중금속농도도 증가하였다.

• 한국수산과학회지
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• 제12권4호
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• pp.281-285
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• 1979

거제만의 수하식 양식굴에서 난소의 이상발육과 팽융된 부분이 관찰되었다. 1978년 $9\~10$월과 1979년 10월에 조사한 결과는 다음과 같다. 1) 7개지점중 화도와 송구에서만 $6.3\~13.3\%$ 검출 되었다. 2) amoeba에 기생된 굴의 무게는 $6.2\~7.0g$이다. 3) 기생된 굴은 수심에 관계없이 상${\cdot}$중${\cdot}$하층에서 다 검출되었다. 4) 난세포에서만 검출되며 amoeba의 크기는 $3\~23\mu$이다. 5) 난세포내에는 $1\~3$개체의 amoeba가 가장 많이 검출되었다. 6) amoeba는 PAS 염색 e양성이며 Eosin에 잘 염색된다. 7) amoeba의 형태와 성상이 Swayer가 보고한 Acanthamoeba sp.와 유사했다. 8) 순수배양하여 형태변화를 봐 고정하고저 한다.

• Animal Systematics, Evolution and Diversity
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• 제16권2호
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• pp.203-211
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• 2000

한국에서 양식되어지고 있는 한국산 굴류 4종, 굴(Crassostrea gigas Thunberg), 바위굴(C. nippona Seki), 강굴(C. ariakensis Fujita et Wakiya), 토굴(Ostrea denselamellosa Lischke)의 유전적 근연관계를 조사하고자 미토콘드리아 DNA의 16S rDNA와 cytochrome c oxidase I (COI) 유전자 일부분의 염기서열을 분석하였다. 16S rDNA의 319 bp와 COI유전자의 710 bp를 PCR 증폭하여 염기서열을 결정하였으며, 염기서열과 아미노산서열을 자료로 하여 UPGMA와 neighbor-joining 방법으로 계통수를 작성하고, 종간 유연관계를 확인하였다. Crassostrea 속과 Ostrea 속간 비교에서는 뚜렷한 유전적 분화를 나타내었으며 계통분석 결과, neighbor-joining 방법에 의한 COI의 아미노산 서열분석에서는 굴과 강굴이 자매군을 형성하는 양상을 보였으나 두 유전자의 염기서열과 A+T 비율 비교에서는 굴과 바위굴이 자매군을 형성하는 것으로 나타났다.

• 한국패류학회지
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• 제29권3호
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• pp.245-250
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• 2013

We investigated the factors of mass-mortality in terms of water temperature and prey, in order to prevent the mass-mortality of cultured oysters at Gamak Bay in Yeosu City in 2007. The real-time water temperature was recorded as high, 28 to 31C, during late August. Nutrients, Dissolved Inorganic Nitrogen (DIN) and Dissolved Inorganic Phosphate (DIP) were downed in September. The analyzed results of chlorophyll a content were 0.78-1.50 ${\mu}gL^{-1}$ and phytoplankton for food resources was 81 cells $mL^{-1}$, both were low. The finding here indicate that Gamak Bay is in an oligotrophic state. The mass-mortality of cultured oysters occurred 43.6% in Gamak Bay. The mortality rate of oyster were above 67.0%, at Wanpo, however, it was showed 18.3% at Gumchun. Therefore, we believe the mass-mortality of cultured oysters at Gamak Bay comes from the destruction of bio-rhythms due to high water temperature and quantitatively and qualitatively decreasing food resources due to the limitation of nutrients.

• 한국패류학회지
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• 제29권3호
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• pp.239-244
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• 2013

Mass mortalities of farmed shellfish, mostly in summer season, thus named mass summer mortalities, have been a global issue in shellfish aquaculture. The 2013 mass summer mortalities in the confined waters of Goseong Bay, Goseong, Korea were quite a unique and intensive for two farmed species, the Pacific oysters, Crassostrea gigas, and bay scallops, Argopecten irradians. The mortalities were progressive from the bottom of the suspended oysters and caged scallops in the waters, reaching up to 80% for the oyster and 95% for the scallop in about 20 days after the first occurrence, early August, 2013. We monitored a wide range of environmental factors, including water temperature, dissolved oxygen (DO), salinity, turbidity, acidity (pH), organic and inorganic matters, chemical oxygen demand (COD), suspected pathogenic agent, and phytoplankton composition throughout the water column where the two species were suspended or caged. Our survey concluded that the hypoxia or anoxia might be a major cause of the mortalities. Here, we detailed the mortalities and ways to arrive at the conclusion.

• 한국발생생물학회지:발생과생식
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• 제25권1호
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• pp.67-72
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• 2021

This study investigated the IGF-1 signal in specific tissues using Pacific oysters artificially matured via water temperature elevation. Pacific oysters were subjected to water temperature elevation from March to June, and 20 were randomly sampled each month. The condition index (CI) and tissue weight rate (TWR) were examined by measuring shell length, shell height, shell width, and soft tissue weight. The IGF-1 signal in tissues (adductor muscle, digestive glands, gills, labial palps, mantle edges, and gonads) was analyzed by sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. From April to June, the TWR of females and males increased from 19.1±2.9 to 21.0±3.6 and 18.2±2.0 to 19.2±2.5, respectively, while the CI remained the same. The IGF-1 signal in each tissue differed. IGF-1 was expressed in the adductor muscle, while tyrosine was expressed in all tissues. The phosphor (p)-ERK and p-AKT activities were high in the adductor muscle, mantle edge, and gonads. IGF-1 signaling affected the growth and maturity of the Pacific oysters examined.

• 한국수산과학회지
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• 제13권4호
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• pp.207-212
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• 1980

1979년 11월부터 1980년 5월까지 한산${\cdot}$거제만 내의 화도, 송도, 소랑 및 추봉양성장에시 양성하고 있는 굴에 대한 패각의 성장, 육중의 증가, 각중에 대한 육중의 비 그러고 부착기당 부착밀도에 따른 패각의 상대성장에 대해 조사하였다. 각고의 성장은 소량산 굴이 가장 좋아 5월에 10.10cm였고, 다른 세지역보다 늦게 수하한 추봉산은 4월과 5월 사이에 급성장하여 5월에는 8.65cm로 성장하여 화도(8.69cm) 및 송도산(8.57cm) 굴과 거의 같은 크기가 되었다. 소량산 굴의 육중은 2월까지 완만하게 증가하다가 2월 이후 5월까지 급성장 하였으며 화도 및 송도산은 12월과 2월, 4월과 5월 사이에 육중의 증가가 많았으며, 늦게 수하한 추봉산은 12월부터 육중의 중가가 서서히 빨라지기 시작하여 4월과 5월 사이에는 급격히 증가하였지만 육중량은 다를 지역의 것보다 적었다. 각중에 대한 육중비는 화도, 추봉 및 송도산의 증가 경향이 비슷하여 12월 이후 차차 증가하지만 소량산의 경우는 2월까지 그 비가 감소하다가 2월 이후 급격히 증가하였다. 굴 부착기당 부착 밀도별 각고에 대한 각장의 성장비 (각형)는 부착개체수가 13개 이하에서는 0.60이상으로 단형이지만 25개체까지는 0.56이었고, 28개체 이상에서는 0.51 이하로 그 비가 현저히 감소하여 장형으로 되었다.

• 한국수산과학회지
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• 제45권1호
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• pp.11-16
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• 2012

In coastal areas that are affected by continuous, seasonal or occasional pollution sources, bivalves accumulate biological contaminants such as pathogenic bacteria. We investigated the effect of natural seawater relaying and electrolyzed seawater depuration on the bacteriological quality of artificially contaminated oysters Crassostrea gigas and short-necked clams Ruditapes philippinarum to suggest an alternative method of shellfish sanitation control.When artificially contaminated oysters and short-necked clams (fecal coliform level 1,700 MPN/100 g) were relayed into a sea area of safe bacteriological water quality, the fecal coliform level dropped to below 110 MPN/100 g after 1 day. The bacteriological quality of oysters and short-necked clams that are contaminated at a fecal coliform level of 1,700 MPN/100 g could be improved, and become appropriate for raw consumption by a single day relay under proper environmental conditions. When artificially contaminated oysters (fecal coliform level 330 MPN/100 g) were depurated with electrolyzed seawater, 94% of fecal coliform was eliminated after 12 h and fecal coliform was undetectable after 24 h. After 24 h depuration with electrolyzed seawater, the fecal coliform level of short-necked clams with initial fecal coliform of 2,400 MPN/100 g was below 20 MPN/100 g. However, the fecal coliform level of short-necked clams with initial fecal coliform of 17,000 MPN/100 g was relatively high, at 790 MPN/100 g, even after 24 h of depuration with electrolyzed seawater, because of the repeated cycle of excretion and accumulation of fecal coliform in shellfish tissue under the closed depuration environment. Such natural seawater relaying and electrolyzed seawater depuration can be restrictively applied to improve or secure the bacteriological quality of oysters and short-necked clams in accordance with safety levels for bivalves for raw consumption.