• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.9-14
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• 2008

A Nano particle is a small particle with at least one dimension less than 100 nm Nanoparticle is currently used in an area cf intense scientific research, due to a wide variety cf potential applications in biomedical, optical, and electronic fields. In order to know the biological effect of the nine Nano particles on fertilized egg of Crassostrea gigas experiments were performed Development rates of control (free Nano particles) C. gigas to a particular larval stage (D-shape) was 78%. Development rate of C gigas to a parcicular larval stage (D-shape) after 24 hours exposure to 0.05ppm of AGZ020, Nano silver, P-25 and SnO were 22%, 52%, 58% and 76%, respectively. However, all fertilized eggs were destructed within 8 hours afters exposure to 20ppm of respective particles. On the other hand, All fertilized eggs were not affected after 24 hours respective exposure to 0.05ppm of In, Sb, Sn, Zn, and Ag-$TiO_2$ particles. However, development rates of C. gigas after 24 hours exposure to 20ppm of In, Sb, Sn, Zn, Ag-$TiO_2$ were 57%, 60%, 50%, 65%, and 64% respectively.

• Korean Journal of Remote Sensing
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• v.38 no.5_3
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• pp.979-989
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• 2022

We examined changes in the shell valve movements (SVMs) of Mytilus edulis and Crassostrea gigas using a Hall element sensor to investigate the early detection of the toxic dinoflagellate Alexandrium pacificum. No increase or decrease was observed in SVMs caused by the non-toxic algae Isochrysis galbana in both M. edulis and C. gigas. However, when M. edulis and C. gigas were exposed to A. pacificum, which causes paralytic shellfish poisoning, the average SVMs for 12 hours before and after exposure increased from 1.25 times/hr to 2.13 times/hr and 2.23 times/hr to 8.91 times/hr, respectively. After exposure to A. pacificum, the SVMs of M. edulis increased rapidly within 1 hour and then decreased gradually. However, C. gigas showed high SVMs until 4 hours after exposure. SVMs of C. gigas appeared to be more sensitive to toxic dinoflagellate than those of M. edulis. Therefore, these results are expected to be used as basic data for the establishment of a biological monitoring system for early detection of the toxic dinoflagellate A. pacificum.

• The Korean Journal of Malacology
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• v.26 no.4
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• pp.317-326
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• 2010

The availability of fast and inexpensive sequencing technology has enabled researchers around the world to conduct many genome sequencing and expressed sequence tag (EST) projects of diverse organisms. In recent years, whole genome projects have been undertaken to sequence ten species from the phylum Mollusca. These include Aplysia californica, Lottia gigantea, Crassostrea virginica, Spisula solidissima, Mytilus californianus, Biomphalaria glabrata, Crepidula fornicata, Elysia chlorotica, Lottia scutum and Radix balthica. Additionally, complete mitochondrial genomes of 91 mollusks have been reported. In Korea, EST projects have been conducted in nine mollusk species that include Nesiohelix samarangae, Pisidium (Neopisidium) coreanum, Physa acuta, Incilaria fruhstorferi, Meretrix lusoria, Ruditapes philippinarum, Nordotis gigantea, Crassostrea gigas and Laternula elliptica. Finally, the mitochondrial genome projects from the Pacific Oyster (Crassostrea gigas) and the rock shell (Thais clavigera) have been conducted and reported. However, no systemic mollusk genome project has so far been conducted in Korea. In this report, the current status and research trends in mollusk genome study in Korea will be discussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.481-486
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• 2009

In 2007, 43.5% mortality of the cultured oyster population occurred in Gamak Bay. Mortality rapidly increase in September and peak in October. To prevent future mass-mortality event, we investigated spawning and variation of oyster body composition. The main spawning period of culture oyster occurred from August to September. Condition index and body composition (protein and glycogen) appeared to be influenced by the spawning activity. Condition index and glycogen content in September were lowest (13.5% and 5.6 mg/g, respectively). However, protein, lipid and glycogen contents did not rapidly recover after the spawning activity. The data indicates that mass-mortality of cultured oysters in Gamak Bay may be due to deteriorated health, spawning activity, stress of the high water temperature and decreasing food resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.702-707
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• 2013

Sleep is an essential biological process of which the underlying regulatory mechanisms involve numerous anatomical structures and biochemical substances that can be compromised by stress and the immune system. Gamma aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the central nervous system (CNS). It is well established that activation of $GABA_A$ receptors promotes sleep. L. brevis BJ20 fermentation of sea tangle and oysters resulted in stress reduction and sleep inducing effects. This is the first study to report that GABA has the ability to induce sleep related hormones in mice; therefore, it has potential use as a natural sleep aid. These results suggested that sea tangle and oysters fermented by L. brevis BJ20 can be used as potential agents for stress reduction and sleep promotion.

• The Korean Journal of Malacology
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• v.14 no.2
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• pp.103-111
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• 1998

참굴에 다환성방향족탄화수소(PAHs)의 축적성과 이 물질들이 미치는 독성을 평가하기 위해 해양환경에서 빈번히 검출되는 PAHs 중의 하나인 fluoranthene을 사용한 모델연구를 수행하였다. Fluoranthene을 0.01-1ppm의 농도로 2주간 참굴에 노출시켰을 때 참굴 조직내의 fluoranthene의 농도는 노출기간 및 노출농도에 비례하여 최고 40-70배까지 증가하였다. 소화맹낭과 폐각근의 지질 과산화물가는 노출기간 및 노출농도에 관련하여 현저히 증가하였으며 수용성단백질의 함량은 노출기간이 길어짐에 따라 서서히 감소하였다. 그러나 glycogen 함량, nucleoside/nucleotide, DNA 및 RNA 함량은 변화하지 않았다. 이 결과로 fluoranthene은 굴의 조직내로 원활하게 축적함을 확인하였다. 또한 과산화지질의 함량은 fluoranthene에의 오염에 대해 신속히 반응하는 지표의 하나로 추정되며 수용성단백질의 감소도 비록 시간적으로 다소 둔감하기는 하나 또 다른 지표가 될 수 있을 것으로 사료된다.

• The Korean Journal of Malacology
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• v.14 no.2
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• pp.113-120
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• 1998

참굴에 다환성방향족탄화수소(PAHs)의 축적성과 이 물질들이 미치는 독성을 평가하기 위해 해양환경에서 빈번히 검출되는 PAHs 중의 하나인 anthracene을 사용한 모델연구를 수행하였다. Anthracene을 0.01-1ppm의 농도로 2주간 참굴에 노출시켰을 때 참굴 조직내의 anthracene의 농도는 노출기간 및 노출강도에 비례하여 최고 25-85배까지 증가하였다. 소화맹낭과 폐각근의 지질 과산화물가는 노출기간 및 노출농도에 관련하여 현저히 증가하였으나 수용성단백질, glycogen, nucleoside/nucleotide 및 핵산의 함량은 변화하지 않았다. 이 결과로 anthracene은 굴의 조직내로 원할하게 축적됨을 확인하였으며 과산화지질의 함량은 anthracene에의 오염에 대한 예민한 생화학적 지표가 될 수 있을 것으로 사료된다.

• Journal of fish pathology
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• v.14 no.2
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• pp.103-105
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• 2001

The effect of opsonization of zymosan with serum on the repiratory burst of haemocytes isolated from the Pacific oyster Crassostrea gigas was investigated. The reactive oxygen species (ROS) produced by the respiratory burst of haemocytes in response to the opsonized or unopsonized zymosan were measured using chemiluminescence (CL). The CL values were increased according to the increment of haemocyte number. The degree of CL amplification by increase of haemocytes from $0.1{\times}10^6$ to $0.5{\times}10^6$ cells/ml was 3-5 times, but comparatively low amplification was elicited by increase of haemocytes from $0.5{\times}10^6$ to $1{\times}10^6$ cells/ml. Chemiluminescences produced by the haemocytes in response to the zymosan opsonized with oyster serum were considerably higher than the CL produced by the haemocytes in response to the unopsonized zymosan.

• Fisheries and Aquatic Sciences
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• v.22 no.9
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• pp.19.1-19.10
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• 2019

We investigated the insulin-like growth factor 1 (IGF-1)/AKT signaling pathway involved in muscle formation, growth, and movement in the adductor muscle of triploid Pacific oyster, Crassostrea gigas. Large and small triploid oysters (LTs and STs) cultured under identical conditions were screened, and the signaling pathways of individuals with superior growth were compared and analyzed. mRNA and protein expression levels of actin, troponin, tropomyosin, and myosin, proteins important in muscle formation, were higher in LTs compared with STs. Expression levels of IGF-1, IGF binding protein (IGFBP), and IGFBP complex acid-labile subunit were also higher in LTs compared with STs. Phosphorylation of the IGF receptor as well as that of AKT was high in LTs. In addition, the expression of phosphomammalian target of rapamycin and phospho-glycogen synthase kinase $3{\beta}$ was increased and the expression of Forkhead box O3 was decreased in LTs. Therefore, we suggested that the IGF-1/AKT signaling pathway affects the formation, growth, and movement of the adductor muscle in triploid oysters.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.145-145
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• 2003

To evaluate the effect of PAHs on fertilization and larval development of the Pacific oyster, Crassostrea gigas via in vivo exposure for 30 days. Conditioned C. gigas adult brood stock was taken from oyster farm in May 2003 and raised in flow through tank at 20-22$^{\circ}C$ with feeding equivalently mixed marine microalgae: Chaetoceros simplex, C. gracilis, Isochrysis galbana and Tetrasemis tetrathele. The oysters were exposed to PAHs cocktail at 200ppb (10 species) until they are fully riped with an untreated group. Motility of sperm, Fertilization and The percent of D-shaped larvae was measured under microscope (Olympus BX-50). Fertilization capability using dry sperm and eggs from both non- and PAHs treated brood stocks was significantly reduced at the treated group (P<0.01). In addition to the origin effect, it was obvious that fertilization of eggs from both group were adversely suppressed in consistent with PAHs level (P<0.01). The percent of D-shaped larvae in treated group was significantly reduced comparing to non-treated. The percent was adversely correlated with PAHs level, which was more significantly reduced in treated group. Therefore, it was obvious that PAHs exposure on the Pacific oyster has adverse affects on the sperm as well as larvae in both maternal and acute source.