• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.452-468
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• 2012

Marine organisms were collected by the stow nets and the stow net on boat fisheries from April 2010 to November 2011 in the Han River Estuary and categorized as 126 species, 61 families, and 5 taxa. The species were consisted with 34 in Crustacea, 5 in Cephalopoda, 79 in Pisces, unidentified jellyfishes in Cnidaria, and Finless porpoise in Mammals. The major species were composed of fish and crustaceans in the Han River Estuary. The dominant species in Crustacea were Chinese ditch prawn (Palaemon gravieri), blue crab (Portunus trituberculatus), Ridgetail prawn (Exopalaemon carinicauda), and mantis crab (Oratosquilla oratoria), and those in Pisces were Korean anchovy (Coilia nasus), and Japanese grenadier anchovy (Coilia mystus). The length structures of the six dominant species have more than one mode in the Han River Estuary. It reflects that the species inhibit during a part of and/or whole lifetime in the Han River Estuary where they utilize as spawning and/or nursery grounds. Freshwater fishes were collected from station D where is the closest location to the Han River stream, and their appearances were well matched with the large amount of freshwater discharge due to flood periods. Principal components analysis (PCA) was carried out with species compositions and showed temporal and spatial differences by the variations of species.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.4
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• pp.463-470
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• 2011

Gonadotropin-releasing hormone receptor (GnRHR) gene is expressed at the anterior pituitary gland and plays a key role in gonad development. This study aimed to investigate molecular genetic characteristics of the GnRHR gene and elucidate the effects of single nucleotide polymorphisms (SNPs) of GnRHR gene on sex steroid level in Japanese flounder (Paralichthys olivaceus). We used polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and sequencing of the GnRHR gene in 75 individuals. We identified three SNPs in the GnRHR gene: P1 locus (C759A and C830T) in the coding region of exon2 which were both linked together and P2 locus (G984T) in the coding region of exon3, which added a new transcript factor (ADR1) and a new methylation site (CG). Only C830T of P1 leads to amino acid changes Thr266Ile. Statistical analysis showed that P1 was significantly associated with $17{\beta}$-estradiol ($E_2$) level (p<0.01) and gonadosomatic index (GSI) (p<0.05). Individuals with genotype BB of P1 had significantly higher serum $E_2$ levels (p<0.01) and GSI (p<0.05) than those of genotype AA or AB. Another SNP, P2, synonymous mutation, was significantly associated with GSI (p<0.05). Individuals with genotype AB of P2 had significantly higher GSI (p<0.05) than that of genotype AA. In addition, there was a significant association between one diplotype based on three SNPs and reproductive traits. The genetic effects for both serum $E_2$ level and GSI of diplotype D4 were super diplotypes (p<0.05). These results suggest that the SNPs in Japanese Flounder GnRHR are associated with $E_2$ level and GSI.

• The Journal of Fisheries Business Administration
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• v.30 no.2
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• pp.1-23
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• 1999

In the Northeast Asian region fisheries agreements of the past regarding high seas as an agreement area were transformed or new agreements were introduced in order to conform to the EEZ regime. However, the existing joint regulatory zone which “open” status is somewhat similar to the high sea not only disappear, but also two new systems were established. To begin with, parties of the agreement claimed their EEZs to be from the territorial sea baselines to the extent set forth, problem of the fishery access of the other party under the agreement is to be solved on the principle of reciprocity and on recognizing of the catch results achieved in the past. In regards to the overlapping zones like neutral zone of the East Sea of Korea(Sea of Japan) and neutral zone to the south of the Cheju Island, provisional measures zones in the Yellow Sea and in the East China Sea, and transitional zone of the Yellow Sea special fisheries management systems reflecting the legal character of the zone involved are applied. Moreover, as fisheries agreements defining open sea as an agreement zone are not able to conform to the EEZ regime, so new fisheries agreements must be taken out from old systems and conceptions, and must be understood and enforced from the new point view. Therefore, countermeasures needed to do so should be developed, and their basic structure is as follows. Firstly, the basic concept of the EEZ regime requires that the coastal states have sovereign rights on their sea zones' natural resources and bear responsibilities appropriate to their allowed jurisdiction. Each Northeast Asian state should adjust the structure of fishing industries and employ advanced fisheries management system, and should make efforts toward such issues of the state policy as increasing fishery resources and preserving ocean environment. Secondly, measures should be developed to solve the international fisheries disputes which are to occur under enforcement of the new fisheries agreements system. In regards to the acts of violation the fisheries laws in the foreign EEZ the principle of jail sentence prohibition is established by the UN Convention on the Law of the Sea, and every fisheries agreement reflects this principle. Therefore, the present question is to consider concrete measures to enable the easy release of the seamen, who violated fisheries laws slightly and well-intently, through establishment and management of the guarantee fund needed to make collateral reasonable. Thirdly, Korean-Russian and Russian-Japanese fisheries relations were formed on the basis of the EEZ regime, since 1992 and 1977 respectively, and are expected to maintain mutually beneficial cooperative character. As for Korean-Chinese-Japanese fisheries relations, the operational problems of overlapping zones, and problem of the permits for EEZ mutual access should be solved on the basis of the principle of reciprocity and equity rather than unilaterally from any side.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4519-4525
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• 2014

Oleanolic acid (OA) is a nutritional component widely distributed in various vegetables. Although it has been well recognized for decades that OA exerts certain anti-tumor activity by inducing mitochondria-dependent apoptosis, it is still unclear that what molecular signaling is responsible for this effect. In this study, we employed cancer cell lines, A549, BXPC-3, PANC-1 and U2OS to elucidate the molecular mechanisms underlying OA anti-tumor activity. We found that activation of MAPK pathways, including p-38 MAPK, JNK and ERK, was triggered by OA in both a dose and time-dependent fashion in all the tested cancer cells. Activation was accompanied by cleavage of caspases and PARP as well as cytochrome C release. SB203580 (p38 MAPK inhibitor), but not SP600125 (JNK inhibitor) and U0126 (ERK inhibitor), rescued the pro-apoptotic effect of OA on A549 and BXPC-3 cells. OA induced p38 MAPK activation promoted mitochondrial translocation of Bax and Bim, and inhibited Bcl-2 function by enhancing their phosphorylation. OA can induce reactive oxygen species (ROS)-dependent ASK1 activation, and this event was indispensable for p38 MAPK-dependent apoptosis in cancer cells. In vivo, p38 MAPK knockdown A549 tumors proved resistant to the growth-inhibitory effect of OA. Collectively, we elucidated that activation of ROS/ASK1/p38 MAPK pathways is responsible for the apoptosis stimulated by OA in cancer cells. Our finding can contribute to a better understanding of molecular mechanisms underlying the antitumor activity of nutritional components.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.134-135
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• 2003

The geographic expansion of the toxic dinoflagellates genus Alexandrium has been shown to be world wide ranging. The members of the genus Alexandrium ocnstituted of 20-30 species did not show substantial differences in their morphology, which is mostly referred in the 'tamarensis species complex', except some species. Though rDNA sequences variations are very few and pseudogene types are so diverse that it is difficult to use them as the specific markers. In this study, we outlined Korean and Japanese A, tamarense and A. catenella regional isolates by phylogenetic analysis inferred from no cutting alignments of LSU rDNA D1-D2 and SSU rDNA sequences to group these regional isolates. The results were compared to RFLP patterns of PCR products targeted chloroplast DNA. Lastly screening of highly repeated microsatellite DNA which is frequently used for population analysis in eukaryotes was conducted. A. catenella regional strains identified by the sequencing of rDNA D1-D2 domain were divided into at least 3 groups of type E, CMC and Chinese type, divergence root may not be deep comparing with that of A. tamarense whose pseudogenes are very variable. Results of RFLP pattern and the phylogeny of the unknown gene targeting chloroplast showed that Korean and Japanese A. catenella regional isolates were divided into 3 types: Korean, Japanese and the third CMC types. Population-specific PCR amplification with Japanese A. catenella type-specific PCR primers was useful method for population analysis of A. catenella. Various types of satellite sequences such as 5 nucleotides repeats were obtained from A. tamarense and A. catenella. The 5 nucleotides repeats were primed at the both 3'and 5' ends, and these repeats were prominent as longer repeated motifs. This repeated DNA was intercalated as internal sequences containing various types subrepeats. It is expected that these satellite DNA would be a useful molecular population marker through detail comparison among Alexandrium regional isolates to trace their transferring pathway and to prevent their human-associated their regional extents.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.11
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• pp.1598-1608
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• 2013

An optimum dietary carbohydrate content is important for maximum fish growth. In this study, we fed Wuchang bream (Megalobrama amblycephala) with either control diet (30.42%) or high carbohydrate diet (52.92%) for 90 d. Fish were fed to apparent satiation three times daily in an aquarium with automatic temperature control and circulated water. Growth performance, plasma biochemical parameters, hepatic morphology and enzyme activities were determined. It was shown that compared to fish fed control diet, fish fed high carbohydrate diet had higher plasma triglyceride and cortisol levels for d 90, and lower alkaline phosphatase level for d 45, lower hepatic superoxide dismutase and total antioxidative capacity for d 90, higher malondialdehyde for d 45 and glycogen content for d 45 and 90 (p<0.05). Histological and transmission electron microscopy studies showed that hepatocytes of fish fed high carbohydrate diet contained large lipid droplets, causing displacement of cellular organelles to periphery of hepatocytes. The relative level of hepatic heat shock protein 70 (HSP70) mRNA of Wuchang bream fed high carbohydrate diet was significantly higher than that of fish fed the control diet for 90 d (p<0.05). These changes led to decreased specific growth rate and increased feed conversion ratio (p<0.05). Upon hypoxia challenge, fish fed high carbohydrate diet had higher cumulative mortality than those fed the control diet (p<0.05). These results suggested that high dietary carbohydrate (52.92%) was detrimental to the growth performance and health of Wuchang bream.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.23-30
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• 2021

To examine the optimal temperature, light intensity, and shell-type for shell-living conchocelis production, we tested the shell infiltration of free-living conchocelis fragments under various environmental conditions. Under a combination of various temperatures (10, 15, 20, 25 and 30℃) and light intensities (1, 5, 10, 20, 40, and 80 μmol m-2 s-1), the optimal infiltration conditions of the evaluated three Pyropia species were 20-25℃ and 5-80 μmol m-2 s-1 for P. yezoensis, 20-30℃ and 20-80 μmol m-2 s-1 for P. seriata, and 20-25℃ and 20-80 μmol m-2 s-1 for P. dentata. The infiltration efficiency of free-living conchocelis for different shell types was greater in Korean and Chinese oyster Crassostrea gigas shells than that in scallop Argopecten irradians and clam Meretrix lusoria shells. These results suggest that oyster shells are suitable substrates for shell-living conchocelis production. In conclusion, the present results for optimal infiltration conditions for free-living conchocelis of the three examined Pyropia species will contribute significantly to the production of stable shell-living conchocelis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.6
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• pp.876-881
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• 1996

To determine the amount of genetic variation among populations of Penaeus chinensis (Osbeck) in the Yellow Sea, 342 bp region of the mitochondrial cytochrome c oxidase subunit I gene was amplified and sequenced. Six haplotypes, which differ by from one to four nucleotide sustitutions, were detected from 34 individuals of 4 populations examined. Mean sequence divergence between pairs of haplotypes was $0.68\%$. Most individuals from 4 populations were shared by the most common genotype. This genotype was distributed evenly in the Korean and Chinese populations. This result is in accordance with findings observed using RFLPs analysis of mtDNA (Hwang et al., 1997). Therefore, it is suggested that P. chinensis should be treated as one unit stock in the Yellow Sea.

• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.140-148
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• 2008

We compared the quality and quantity of volatile components in salt-dried croakers prepared by different methods and obtained from different locations. In total, 110 compounds were found among regular- and delay-type salt-dried croakers purchased from two locations in Hong Kong. The major chemical classes included miscellaneous compounds(17), pyrazines(16), alcohols(15), and sulfur-containing compounds(13). Fish obtained in different locations but prepared by the same method differed only slightly in the number of identified compounds. In general, fish prepared by the delay method had a larger number of compounds compared to fish prepared by the regular method. Further, a greater number and higher levels of compounds were found in the fish obtained from one of the two locations. Overall, the delay preparation method resulted in a greater number of compounds with stronger intensity compared to the regular method.

• The Journal of Fisheries Business Administration
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• v.39 no.3
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• pp.67-90
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• 2008

In this study, we aimed to build the basic calculation model for linkage effects of fishery industry among Korea, China and Japan. For the calculation, we reconstructed the asian international input-output table, and on the basis of the reconstructed table, we made some analyses on the inter-relations among 3 nations focusing fishery industry. As the results, some positive backward linkage offsets of the fishery industries were found among 3 nations, and especially, production inducing effect of Chinese fishery industry to Japanese supplier was remarkable.