• Biomolecules & Therapeutics
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• v.6 no.2
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• pp.191-198
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• 1998

Vsrio vulnificus is an estuarine gram-negative human pathogen that affects people with chronic hepatitis, alcoholic cirrhosis, diabetes mellitus or other underlying diseases. V. vulnificus infection is mediated primarily by consumption of raw fish or by exposure of pre-existing wounds to seawater, causing permanent tissue damages or fatal septic shock. We have been developing a vaccine against V. vulnificus composed of whole cell Iysate of a V. vulnificus O-antigen serotype 4 strain. Oral administration of the V. vulnificus;oral vaccine;immunogenicity;protective efficacy vaccine elicited a high serum antibody response in rabbits. The induced antibodies were reactive not only to the homologous strain but also to heterologous O-antigen serotype strains, indicating cross-reactivities among serotypes. Western blot analysis revealed that the antibodies are mainly specific for outer membrane proteins (OMPs) and reacted equally well with OMPs purified from 9 O-antigen serotypes. The rabbit antisera showed opsonophagocytic killing activity against heterologous strains as well as the homologous strain. Passively transferred rabbit antisera into mice were protective against a lethal V. vulnificus infection. These data demonstrate that oral administration of the V. vulnificus vaccine induced a systemic antibody response which had a protective efficacy against V. vulnificus infections, suggesting that this vaccine preparation could be used to develop an oral vaccine against V. vulnificus.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.154-162
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• 2011

Seawater quality was investigated each month at 30 stations near Tongyeong, South Korea, to provide data for the effective use of coastal fisheries and the reduction of economic damage to marine products. Water temperature was lowest in January and highest at the end of August. Neither extremely low water temperature below $4^{\circ}C$ nor fish damage caused by low water temperature was observed. Salinity ranged from 24.04 to 34.39 psu in the surface layer and from 29.92 to 34.39 psu in the bottom layer. The minimum salinity, attributable to rainfall events, was observed in July; salinity increased to high of about 34 psu in November. Low dissolved oxygen (DO), below 4 mg/L, was observed at Wenmun and Buksin Bays during May to October. Concentrations of $NO_2$-N, $NO_3$-N, and $PO_4$-P were low from March to September and high from October to February. Transparency was 6 m on average and was high in Wenmun Bay. Chemical oxygen demand (COD) and chlorophyll a (Chl. a) were high during summer, when the water temperature was high. With cluster analysis based on environment factors related to water quality, the study area could be divided into three main sea areas: Buksin Bay, coastal seawater, and offshore seawater. Buksin Bay was characterized by low salinity, high DO and Chl. a, and high transparency in the surface layer and by low DO and high $NH_4$-N in the bottom layer. Offshore seawater had high salinity and $NO_3$-N and low Chl. a concentration. In summer season that oyster need lots of phytoplankton, $NO_3$-N and Chl. a concentrations at this study area were low compare to Gwangy-ang and Gamak Bays. In winter, a sea squirt swallow much more than other season, the Chl. a concentrations were also low than Gwangyang and Gamak Bays.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.595-600
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• 2002

Comparison of blood properties in juvenile black seabream (Acanthopans schlegeli) between transfer from seawater to freshwater (sFW) and transfer from freshwater to seawater (fSW) were investigated for 60 days. Plasma cortisol levels in sFW were significantly increased from 34.2 $\pm$ 28.6 ng/mL at the beginning to 365.6 $\pm$ 136.0 ng/mL at 3 hours, and decreased to the beginning level at 24 hours. However, in fSW, no significant differences in the cortisol levels were recognized throughout experimental period. No significant difference was found in the glucose levels between sFW and fSW. The transfer from seawater to freshwater of juvenile black seabream resulted in reduced $Na^{+}\;and\; Cl^{-}$ concentrations for 24 hours (decreasing from 165.3 $\pm$ 2.5, 146.0$\pm$ 2.2 to 118.3 $\pm$ 12.3, 78.0$\pm$ 7.0 mEq/L, respectively), but these were completely recovered the beginning levels at 30 days. Total protein and AST showed no significant differences between the two rearing conditions, while ALT was markedly elevated at 3 hour in sFW and at 24 hours in fSW. Ht in sFW was increased from 18.5 $\pm$ $0.6\%$ at the beginning to 25.3 $\pm$ $4.0\%$ at 12 hours, and was decreased to the beginning level at 24 hours. Ht, RBC and Hb in fSW were also significantly higher at 12 hours, but recovered to their initial levels at 24 hours. All fish were dead until 50 days in sFW while survival rate in fSW was $85\%$ at the end of experiment.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.293-303
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• 2005

Japanese medaka, Oryzias latipes is widely distributed in the North East Asia including Korea, Japan and east China, and commonly used for freshwater toxicity tests and cytotoxicological studies worldwide. In this study, a series of experiments were conducted to identify the potential of the fish as a standard test species for saltwater toxicity evaluation such as marine receiving waters, ocean-dumped materials and sediment pore waters etc. Hatching, growth and mortality rates of the fish were estimated with the wide ranges of salinity from freshwater to seawater (35 psu). Direct exposure of the fertilized eggs in freshwater to the wide ranges of salinity (from 0 to 35 psu) without pre- acclimation to the saltwater revealed no significant differences in hatching rates by salinities (p =0.24). On the other hand, medaka larvae hatched in freshwater and exposed to saltwater directly showed high mortality at > 25 psu treatment groups (p < 0.0001). However, there was no significant difference in mortality of medaka larvae hatched in 13.8 and 14.2 psu at the wide ranges of salinities ($0\~35$ psu). Growth rates of medaka larvae hatched in the above two salinities showed no differences in body length either from 0 to 35 psu treatment groups (p =0.64 for 13.8 psu group and p=0.32 for 14.2 psu group). The number of gill chloride cell in medaka larvae sharply increased when the larvae were exposed to high salinity. Reference tests with zinc chloride revealed 96h $LC_{50}=8.84(7.19\~10.87)mg\;L^{-1}$ using 7~10 day old medaka larvae. These were comparable or better sensitivity in comparison with the other standard test species such as North American sheepshead minnow Cyprinodon variegatus. Based on the results of these experiments, hatching rates and larvalmortality of medaka must be good toxicity parameters for seawater bioassay and the species seems to be a good standard species for both the freshwater and seawater toxicity test.

• Journal of Life Science
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• v.21 no.10
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• pp.1487-1493
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• 2011

E. tarda, a fish pathogen, can survive in seawater under relatively high salt conditions as well as in fish under physiological salt conditions. Bacterial growth under different salt concentrations may influence the expression of genes involved in bacterial structure and physiology. The growth rate of E. tarda culture in high salt (3.5% NaCl) was similar to that in low salt (1.0% NaCl, physiological salt concentration). Interestingly, the strain moved much faster in low salt conditions than in high salt conditions. Electron microscopic observation demonstrated that the bacterial cells grown in high salt had less or no flagellation. Obvious flagellation was observed in the parental strain E. tarda CK41 grown in low-salt condition. Two putative genes coding flagellin were identified in the E. tarda genome sequences. The amino acid sequence comparison of each gene revealed 93% identities. A flagellin gene was PCR amplified and cloned into a cloning vector. Using an E. coli protein expression system, a part of flagellin protein was overexpressed. Using the purified protein, an anti-flagellin antibody was raised in the rabbit. Immunoblot analyses with flagellin specific antibody demonstrated that E. tarda CK41 expressed falgellin in low salt conditions, which is consistent with the results seen in motility assay and microscopic observation. This is the first report of salt regulated flagella expression in E. tarda.

• Korean Journal of Veterinary Research
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• v.47 no.3
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• pp.291-298
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• 2007

Olive flounder, Paralichthys olivaceus is one of the most important cultured fish in Korea, its farming has been negatively impacted by viral, bacterial and parasitic diseases. Streptococcal infection was considered as a serious problem because of significant economic losses in olive flounder farm industry. The development and evaluation of vaccine for protection against infection by this agent were required. We evaluated the safety and efficacy of ${\beta}$-hemolytic Streptococcus (S.) iniae vaccine on olive flounder Three hundreds of flounders (weight $119.8{\pm}20.7g$, body length $22.6{\pm}1.4cm$) were reared in 0.5 tons aquaria in land-marine tank system. Seawater was provided from the sea of Inchon in Korea, and water temperature was set to $22^{\circ}C$ and $25^{\circ}C$ in the vaccination and challenge test, respectively. We used the formalin-inactivated ${\beta}$-hemolytic S. iniae (F2K) vaccine (M VAC INIAE; Kyoritsu seiyaku, Japan) originated in Japan. The vaccine was intraperitoneally administered to fish. Both of vaccinated group and control group were challenged with intraperitoneally injection by virulent S. iniae SI-36 isolates with $1.0{\times}10^7CFU/fish$ at 3 weeks after vaccination. Difference on mortality of control and vaccinated group (90.0 and 15.0%, 76.5 and 8.0% respectively) at two trials were found significant (p<0.05), and relative percent survival were 83.4% and 89.5%, respectively. The dead fishes were showed dark pigmentation of skin, abdominal extension, hemorrhagic ascites, and liver necrosis, and isolated the S. iniae strain from ascites, liver and kidney. We confirmed the safety and efficacy of ${\beta}$-hemolytic S. iniae vaccine by determinations of the optimal management condition and artificial challenge test in olive flounder.

• Journal of Aquaculture
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• v.19 no.1
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• pp.19-24
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• 2006

The objective of this study was to develop an efficient control method for the Alella macrotrachelus parasitic cultured black porgy, Acanthopagrus schlegeli utilizing the superior osmoregulatory ability of the host fish. The average number of the parasites on a fish was 5 worms (all female), which were attached to the cartilage of gill filament by their bulla. Morphologically, the parasite was tripartite with each length of $1822.1{\pm}521.5{\mu}m$ for the trunk $1825.0{\pm}495.8{\mu}m$ for the cephalothorax, and $134.2{\pm}43.1$ for the bulla. In histological observations, it was found that the female parasite took gill lamellae. Damage and loss of gill lamellae by the parasite caused hemorrhage and anemia in the fish. All parasites died within 48 hours by osmotic shock of freshwater or $5{\sim}15\%_{\circ}$ seawater treatment. These results suggest that Alella macrotrachelus could be controled by hyposmotic treatment.

• Journal of Life Science
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• v.8 no.5
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• pp.589-597
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• 1998

In order to effectively utilize marine processing by-product such as fish scale, chemical compositions for the scale were analyzed. The selected fishes were gray mullet, Mugil cephalus, living in the sea and carp, Cyprinus carpio in the fresh water, having a lot of scales among the fishes living in seawater and fresh water. And we also investigated the difference in the chemical compositions between gray mullet and carp, depending on both living circumstances. The major components of the scales were found to be crude ash and crude protein which were each about 49% for gray mullet and which were about 20% and 79% for carp, respectively, on the basis of dried scales. The proteins extracted from both scales proved to be collagen through amino acid compositions and SDS polyacrylamide gel electrophoretic patterm. Also this scale collagen was assumed to by Type I collagen because the migration rate of $\alpha$1 and $\alpha$2 subunit of the collagen were almost the same those as calf skin Type I collagen. Most of proteins from gray mullet was collagen, however, the collagen content in proteins from carp was estimated to be only about 53%, on the basis of the ratio of hydroxyproline to protein. The crude ashes of both scales identified to be hydroxyapatite through element compositions and X-ray diffraction analysis. In conclusion, both fishes in different living circumstances were almost similar to in the chemical compositions but chemical contents for crude ash and crude protein.

• Journal of fish pathology
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• v.19 no.1
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• pp.7-15
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• 2006

Amyloodinium sp. was found on the gills of mullet (Mugil cephalus) cultured on land. No external symptoms in the diseased fish were found except decoloration of the gills. In fresh preparations of the gills the parasites were opaque round or oval shape with a bright nucleus and 43.5 ㎛ (18.2～72.7, n=20) in size. In preparations added a drop of Lugol solution, they were black with the same shapes in fresh preparations and 43.5 ㎛ (n=20) in size. The parasites were stained black and blue in a droplet of Lugol solution and Diff-Quick III solution, respectively and their sizes were a little larger than in wet preparations. After stained with May-Grunwald Giemsa, the parasites appeared granular eosinophlic in the peripheral cytoplasm and granular strong basophilic in the center. In silver impregnated specimens the peripheral granules were negative and the central ones positive. The granules appeared brown in purplish cytoplasm after staining with Lugol solution. The parasites developed by binary division when they were cultivated in filtered seawater at 20℃. Histopathologically severe epithelial hyperplasia and fusion in the gill filaments resulted in clubbing, especially the proximal region of the filament. Epithelial hyperplasia was also found in the basal regions of the gill filaments and some epithelial cells were occasionally detached from the filaments. Some pear-shaped trophonts of the parasites with rhizoid attached on the gill filaments showing hyperplasia of the epithelial cells and mucous cells.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.82-93
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• 1998

Monthly changes of the gonad follicle index (GFI), reproductive cycle, egg-diameter composition, first sexual maturity of the Pacific oyster, Crassostrea gigas, were studied based on the samples which have been collected from the intertidal zone of Poryong west coast of Korea, from January to December, 1996. C. gigas, is dioecious, while a few individuals are alternatively hermaphroditic. Monthly variation of gonad follicle index (GFI) used for determination of spawning period, coincided with the reproductive cycle. GFI increased from April when seawater temperatures gradually increased and reached the maximum in May. And then, GFI sharply decreased from June to September due to spawning. Reproductive cycle of this species can be divided into five successive stages: in females, early active stage (March to April), late active stage (April to May), ripe stage (May to August), partially spawned stage (June to September) and spent/inactive stage (September to February); in males, early active stage (February to March), late active stage (April to May), ripe stage (May to September), partially spawned stage (June to September) and spent/ inactive stage (September to February). The diameter of fully mature eggs are approximately 50um. Spawning occurred from June to September, and two spawning peaks were observed in June and August when the seawater temperature was above $20^{\circ}C$. Percentages of the first sexual maturity of males of 20.1-25.0 mm in shell height were over $50\%$, while those of females of 25.1-30.0 mm in shell height were over $50\%$. All the males of > 30.1 mm and all the females of ^gt; 35.1 mm completed their first sexual maturity. The results suggest that C. gigas has a protandry phenomenon. Sex ratios of 919 oysters observed were 453 females $(49.29\%)$, 429 males $(46.68\%)$, 16 hermaphrodites $(1.74\%)$, and 21 indeterminate individuals $(2.29\%)$. In age class I, sex ratio of males were $64.00\%$, thus, a higher percentage than that of females. It was noted that $64.00\%$ of the young males (age class I) were more functional than females in age class I, but 2-3 year-old oysters showed higher percentage of females. Percentages of hemaphrodites in 2-3 year classes were relatively higher than those in other year classes. Histological pattern of hermaphrodites can be divided into two types: Type I (hermaphrodite having a number of newly formed developing oocytes on the oogenic tissues within a degenerating spermatogenic follicle after discharge of numerous spermatozoa) and Type II (hermaphrodite having two separate follicles in the same gonad).