• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.225-233
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• 2011

This is the attempt to study the fish assemblages in eelgrass bed of Jeogu on Geoje Island, Korea. Samples were collected by surf net monthly from August 2009 to July 2010. A total 38 species, 2,335 individuals, and 5,289.8g of fishes were collected. The dominant species were Chaenogobius annularis, Gymnogobius heptacanthus, Rudarius ercodes, Siganus fuscescens, Ditrema temminckii, Takifugu niphobles, Aulichthys japonicus, Pseudoblennius cottoides, Syngnathus schlegeli, Sebastes schlegelii, Pterogobius elapoides, Urocampus nanus, Takifugu pardalis, Hypodytes rubripinnis which accounted for 94.2% of total number of individuals of fish collected. Eelgrass biomass showed a peak in August (DW 121.5g/m$^2$), low values in November (DW 74.9 g/m$^2$) to February (DW 49.3g/m$^2$), and started growing from May (DW 112.8g/m$^2$). Gymnogobius heptacanthus, Sebastes schlegeli, Takifugu niphobles, Syngnathus schlegeli, Urocampus nanus were collected year-round with no clear relationship to the biomass of eelgrass bed.

• Development and Reproduction
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• v.23 no.4
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• pp.367-375
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• 2019

Pufferfish (Takifugu spp.) are economically important edible marine fish. Mistakes in pufferfish classification can lead to poisoning; therefore, accurate species identification is critical. In this study, we used the mtDNA cytochrome c oxidase subunit I gene (COI) to design specific primers for six Takifugu species among the 21 domestic or imported pufferfish species legally sold for consumption in Korea. We rapidly and simultaneously identified these pufferfish species using a highly efficient, multiplex polymerase chain reaction (PCR) system with the six species-specific primers. The results showed that species-specific multiplex PCR (multiplex species-specific polymerase chain reaction; MSS-PCR) either specifically amplified PCR products of a unique size or failed. MSS-PCR yielded amplification fragment lengths of 897 bp for Takifugu pardalis, 822 bp for T. porphyreus, 667 bp for T. niphobles, 454 bp for T. poecilonotus, 366 bp for T. rubripes, and 230 bp for T. xanthpterus using the species-specific primers and a control primer (ca. 1,200 bp). We visualized the results using agarose gel electrophoresis to obtain accurate contrasts of the six Takifugu species. MSS-PCR analysis is easily performed and provides identification results within 6 h. This technique is a powerful tool for the discrimination of Takifugu species and will help prevent falsified labeling, protect consumer rights, and reduce the risk of pufferfish poisoning..

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.645-653
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• 1998

Twenty seven species of pufferfishes (family Tetraoaontidae) have been examined to find their generic characters based on vertebrae and pterygiophore characters of specimens collected in 20 localities along the coast of Korea from March, 1991 to March, 1994. It was divided by 3 groups based on vertebrae number as follow : the genera Lagocephalus, Pleurancanthus, Spheoides, Arothron, Chelonoeon and Canthigaster have 17$\~$19 vertebrae, genera Ephippion, Boesemanichthys and Feroxodon have 20 vertebrae, and genus Takifugu have 19$\~$25 vertebrae, The number of vertebrae ranged from 17 to 25 with the maximum of 25 in Takifugu obscurus. The modal number of vertebrae in Lagocephalus is 17 (L. lunaris), 18 (L. inermis), and 19 (L. gloveri, L. wheeleri, L. larigatus), with the lower number more specialized. Paired neural spines appear at number of the 1st$\~$5th vertebrae in Takifugu pardalis, Takifugu obscurus and at number of the 1 st$\~$4 th vertebrae in the other species and genera. All of the species of Lagocephalus and Pleurancanthus have dorsal and ventral pterygiophores processes, and flat-shaped epural, while none of the abdominal vertebrae processes complete haemal arches. The neural and haemal spines of the last few caudal vertebrae aye shorter in Pleurancanthus than in the other genera, associated with the depressed caudal peduncle. The genus Canthigaster is distinguished the first pterygiophores of the dorsal and ventral fins is always much larger than the others genera. Based on the haemal arches and spines of the abdominal vertebrae, genus Canthigaster has different characters from the other genera of the family Tetraodontidae.

• Journal of Life Science
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• v.24 no.5
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• pp.491-497
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• 2014

Nowadays, starfish is one of problems about interruption of marine ecosystem, so many researchers are focusing on application of the starfish (Asterias amurensis). In this study, we investigated the contractile and relaxant activity of the smooth muscles and the antimicrobial and antioxidant activity of six different tissues (muscle, gut, liver, tube feet, gonads, and body) of A. amurensis. Frozen samples were extracted with distilled water containing 1% acetic acid. Extracts from all the tissues, except the body tissue, showed potent antimicrobial activity against Escherichia coli D31. The dorsal retractor muscles (DRM) of muscle and gut extracts showed strong contraction responses. On the other hand, contractile activity on esophagus of squid Todarodes pacificus could be detected in all tissues tested. The contractile activity of the liver extract was higher than that of the other tissues. The body, tube feet, and liver extracts showed the contractile activity on the intestine of the panther puffer fish (Takifugu pardalis). Relaxation response on the DRM of starfish (A. pectinifera) was observed in all tissues tested. Increased antioxidant activity was observed in the gut, liver, and body extracts. The results suggest that the starfish (A. amurensis) is a potential source of novel bioactive compounds.

• Korean Journal of Ichthyology
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• v.13 no.3
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• pp.181-189
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• 2001

Spawning behavior of the Takifugu pardarlis (Temminck et Schlegel) was observed on the Jook-do coast in Tongyong from March 1997 to June 1999. The spawning ground was locted in the intertidal zone between Tongyong and Koje-do. Its bottom was mainly gravels and stones, and its depth was 0.5~1.0 m. Spawning season was from the end of the March to the middle of May. During the spawning season, the mature fishes formed school a of 10~30 individuals, then moved to the spawning ground together. When a mature female spawned eggs, the attendant males fertilized them at the same time. The fertilized eggs obtained from the parent fishes caught at the spawning ground were adhesive, opaque and spherical, measuring 1.14~1.24 mm (mean 1.19 mm, n = 50) in diameter with numerous tiny oil globules. Hatching period was about 205 hours after fertilization at water temperature of $18.0{\pm}0.5^{\circ}C$. The newly hatched larvae were 2.92~3.10 mm (mean 3.01 mm, n = 20) in total length (TL), had a large yolk, and 11~13+14~15 = 25~28 myomeres. At 5 days, the larvae had attained 3.79~3.85 mm (mean 3.82 mm, n = 20) in TL and had transformed into the postlarval stage. At 15 days, the postlarvae had attained 7.78~7.90 mm (mean 7.84 mm, n = 20) in TL. At 21 days, had larvae attained 10.15~10.27 mm (mean 10.21 mm, n = 20) in TL and had reached the juvenile stage. All fins were formed with a complete set of fin rays having the following counts: dorsal fin rays 11~12; anal fin rays 9; pectoral fin rays 14~15; caudal fin rays 11~12.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.218-230
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• 2020

The single anatomical attribute that has the greatest influence on acoustic scattering from fish is the presence or absence of a swimbladder. This study examined the effect of removing the gas from the swimbladder on the broadband backscattering characteristics of six species of swimbladdered fish: striped beakperch Oplegnathus fasciatus, black scraper Thamnaconus modestus, dark-banded rockfish Sebastes inermis, goldeye rockfish Sebastes thompsoni, black rockfish Sebastes schlegeli and panther puffer Takifugu pardalis. Before and after removing the gas from the swimbladder, the species-specific, frequency-dependent backscattered echo signals from anaesthetized individuals of each fish species were measured at approximately 1° intervals spanning a 90° aspect angle range from -45° (head down) to +45° (head up) using a broadband echo sounder operating at 100-200 kHz. The relationship between the wavelength-normalized backscattering cross section (σ/λ²) and fish length (L/λ) was calculated for each species. The average σ/λ² value for the six fish species at a L/λ range of 19.79-25.85, with a mean of 22.89, was reduced by approximately 52.3% when the gas was removed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.129-134
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• 2014

Two neuropeptides were purified from the acidified tube feet extract of the starfish Asterias amurensis by C18 reversed phase and size-exclusion high-performance liquid chromatography (HPLC). The tube feet extract and the purified peptides (AST-I and AST-II) showed potent contractile activity on dorsal retractor muscle (DRM) of the starfish Asterina pectinifera and intestine (smooth muscle) of the panther puffer Takifugu pardalis. Treatment of the purified peptides with dithiothreitol (DTT) for 60 min at $37^{\circ}C$ significantly altered their retention times, suggesting that these compounds contained disulfide bonds. The molecular weights of AST-I and AST-II were determined to be 2064.2 Da and 6137.2 Da, respectively, by MALDI-TOF mass spectrometry.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.122-128
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• 2014

The present study was performed to examine the contraction and relaxation responses of the smooth muscles, and search for antimicrobial and antioxidant activities in the tissues, of the starfish Asterina pectinifera. Frozen samples were extracted with distilled water containing 1% acetic acid. Extracts from all tissues showed potent antimicrobial activity against Escherichia coli D31. Relatively high levels of antimicrobial activity were also detected in the body extracts. Liver, tube feet, and body extracts caused contraction responses in the dorsal retractor muscles (DRM) of the starfish. In contrast, all tissues examined exhibited contractile activity in the esophagus of squid Todarodes pacificus. In addition, liver and gonad extracts caused contraction responses upon application to the intestine of the puffer fish Takifugu pardalis. Relaxation effects on the DRM of starfish were identified in most of the extracts, while no relaxant activity was detected in body extracts. Extracts from all tissues examined also exhibited antioxidant activities. The results of this study suggest that starfish are a potential source of novel bioactive compounds.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.12a
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• pp.121-129
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• 1999

When continuous media are transmitted over the communication networks, asynchrony which can not maintain temporal relationships among packets may occur due to a random transit delay. There exist two types of synchronization schemes ; for guaranteed or non-guaranteed resource networks. The former which applies a resource reservation technique maintains delay characteristics, however, the latter supply a best-effort service. In this paper, I propose a intra-media synchronization scheme to transmit continuous media on general networks not guaranteeing a bounded delay tome. The scheme controls transmission times of the packets by estimating next delay time with the delay distribution. So, the arriving packets may be maintained within a limited delay boundary, and playout will be performed after buffering to smoothen small delay variations. The continually increasing delay due to network overload causes buffer underflow at the receiver. To solve it, the transmitter is required to speed up instantaneously. Too much increase of transmission-rate may cause network congestion. At that time, the transmitter drops the current packet when informed excessive delay from the receiver.

• Korean Journal of Food Science and Technology
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• v.23 no.3
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• pp.306-310
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• 1991

A simplified mathematical model to estimate changes in total acidity of Chinese cabbage kimchi during fermentation was developed as a function of temperature and salt concentration. Assuming that tolerable acceptability reached at 0.75% total acidity, the shelf-life of kimchi was predicted by the model. The predicted value was in good agreement with the actual shelf-life measured by organoleptic tests.