• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.132-138
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• 2019

Among several marine-derived microorganisms isolated from the coast of Jeju Island that had antimicrobial activity against fish disease pathogens, Bacillus subtilis MD-02 was tested for its dietary effect on the innate immune response and disease resistance of olive flounder. Strain MD-02 was fed to the olive flounder at a concentration of $1.2{\times}10^4$, $1.2{\times}10^6$, or $1.2{\times}10^8CFU/100g$, respectively. Consequently, the hematocrit was higher in these three groups than that in the control group at 4 weeks, and the aspartate aminotransferase and alanine aminotransferase levels were decreased in the $1.2{\times}10^8$ and $1.2{\times}10^4CFU/100$ groups compared with the control group levels. The amylase activity and total protein were significantly increased in the $1.2{\times}10^4CFU/100g$ group at 3 weeks. The innate immune response, determined from the lysozyme and macrophage activities, was higher in the $1.2{\times}10^8CFU/100g$ group than in the control group. In addition, treatment of the olive flounders with Streptococcus parauberis at $1.2{\times}10^6CFU/ml$ confirmed the mortality rate, which was 100% in the control group and 40-60% in the groups fed B. subtilis MD-02, indicating that the fish had resistance to fish disease pathogens. Therefore, it was confirmed that when fed MD-02, olive flounder builds an innate immune response and acquires resistance to fish disease pathogens, indicating that B. subtilis MD-02 can be developed as a beneficial feed additive.

• Journal of fish pathology
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• v.26 no.2
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• pp.89-97
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• 2013

The study was carried out to investigate the changes of hematological parameters induced by waterborne exposure of chromium (Cr) in the mullet, Mugil cephalus. The mullet was exposed to sub-chronic concentrations of chromium (0, 25, 50, 100, $200{\mu}g/L$ Cr) for 4 weeks. The major hematological findings were significant decreases in the red blood cell (RBC) count and hematocrit value in mullet exposed to ${\geq}50{\mu}g/L$ Cr. Although serum calcium concentration was significantly reduced at ${\geq}50{\mu}g/L$ Cr, magnesium concentration was found to be significantly increased at ${\geq}100{\mu}g/L$ Cr. The serum glucose and total protein concentrations were significantly increased at $200{\mu}g/L$ Cr. However, serum triglyceride concentration did not show any noticeable changes in the range of $25{\sim}200{\mu}g/L$ Cr of chromium compared to control group during the experimental period. A significant increment of GOT (glutamic oxalate transminase) and GPT (glutamic pyruvate transminase) activities was noticed at ${\geq}100{\mu}g/L$ Cr. These results indicate that hematological and serum biochemical changes in the mullet by waterborne exposure to chromium are affected at more than $50{\mu}g/L$ Cr.

• Journal of fish pathology
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• v.14 no.1
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• pp.37-45
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• 2001

This study was carried out to determine the effects of various iron concentrations on the hemochemical changes of olive flounder, Paralichthys olivaceus exposed for 50 days. The flounder exposed to iron concentration 0.97 mg/$\ell$ started to increase significantly in serum iron and magnesium concentrations after 20 days. The low concentration of serum calcium concentration was observed at 30 days of the experiment in iron concentration 0.97 mg/$\ell$. Serum total protein, albumin and glucose concentrations initiated to decrease from 30 days at the iron concentrations of 0.97 mg/$\ell$ or up. Total cholesterol concentration was increased significantly after 40 days at iron concentration 0.97 mg/$\ell$. A significant increment of GOT, GPT and LDH activities in the flounder serum was noticed after 40 days at iron concentrations over 0.97 mg/$\ell$ without significant changes of Al-P. These results indicate that flounder can be affected by iron in terms of inorganic elements, organic substances and enzyme activity in serum when they were exposed to the iron concentrations 0.97 mg/$\ell$ or higher for 30 days.

• Journal of fish pathology
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• v.20 no.2
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• pp.119-127
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• 2007

Phosphoinositide-specific phospholipase Cδ (PLCδ) plays an important role in many cellular responses and is involved in the production of second messenger. The present study was conducted to characterize the catalytic and regulatory properties of the PLCδ of Misgurnus mizolepis (ML-PLCδ). The ML-PLCδ gene was cloned and expressed under according to the method of the previous report (Kim et al., 2004), and its recombinant protein was purified by successive chromatography using Ni2+-NTA affinity column. The recombinant ML-PLCδ showed a concentration-dependent PLC activity to phosphatidylinositol 4,5-bisphosphate (PIP2) or phosphatidylinositol (PI). Its activity was absolutely Ca2+-dependence, which was similar to mammalian PLCδ isozymes. The Ca2+ concentration yielding maximal activation of ML-PLCδ was 100 μM. However, the activity was decreased interestingly by a polyamine, such as spermine and spermidine. In vitro assay using cholate-micelle cell, ML-PLCδ activity was inhibited in dose-dependent manner by sphinogosine but increased by phosphocholine . In the lipid-binding assay, ML-PLCδ was strongly bound to LPA, PI(3)P, PI(4)P, PI(5)P, PI(3,5)P2, PI(4,5)P2, PI(3,4,5)P3 and PA, but it showed the low affinity to S1P, PI(3,4)P2 and PS. Taken together our results, it is suggested that the general catalytic and regulatory properties of ML-PLCδ are similar with those of mammalian PLCδ1 isozymes, but the N-terminal extended piscine phospholipase Cδ1 (ML-PLCδ) might reflect some distinctions in regulatory properties and inositol-lipid binding specificity between piscine ML-PLCδ and mammalian PLCδ isozymes.

• Development and Reproduction
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• v.9 no.2
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• pp.135-142
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• 2005

Vitellogenins(VTGs) are the precursor of egg-yolk proteins in most oviparous species from invertebrates to vertebrates. In oviparose vertebrates, VTGs are synthesized in the liver and transported through the blood to oocytes. In female fish, concentrations of plasma VTG increase rapidly at onset of vitellogenesis in the normal reproductive cycle. Male fishes also possess the gene for VTG, but plasma concentrations of the protein typically remain small, presumably due to low levels of endogenous estrogens. However, exposure of males to exogenous estrogenic mimics can result elevated. Therefore, the VTG in fish can be used as a useful biomarker for appropriate tools of endocrine disrupting compounds effects. In this studies, we prepared the test methods that can measure the plasma VTG level in the gobies that live in polluted area with mimic estrogen. For the purpose, we purified VTG of floating goby(Chaenogobius annularis) and prepared specific monoclonal and polyclonal antisera to yolk protein, then developed a sandwich competitive ELISA system for measurement of plasma VTG levels. Validation for the ELISA system using monoclonal and polyclonal antibodies against VTG was tested. The absorbance curve of serial dilutions of serum from vitellogenic female was paralleled to the standard curve of VTG, but normal male was not paralleled. The developed sandwich ELISA system was measured for VTG levels in plasma of common goby(Acanthogobius flaviman) and javeline goby(A. hasta) as well as in plasma of floating goby(C. annularis).

• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1459-1469
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• 2008

Using a rotating biological contactor modified with a sequencing bath reactor system (SBRBC) designed and operated to remove phosphate and nitrogen [58], the microbial community structure of the biofilm from the SBRBC system was characterized based on the extracellular polymeric substance (EPS) constituents, electron microscopy, and molecular techniques. Protein and carbohydrate were identified as the major EPS constituents at three different biofilm thicknesses, where the amount of EPS and bacterial cell number were highest in the initial thickness of 0-100${\mu}m$. However, the percent of carbohydrate in the total amount of EPS decreased by about 11.23%, whereas the percent of protein increased by about 11.15% as the biofilm grew. Thus, an abundant quantity of EPS and cell mass, as well as a specific quality of EPS were apparently needed to attach to the substratum in the first step of the biofilm growth. A FISH analysis revealed that the dominant phylogenetic group was $\beta$- and $\gamma$-Proteobacteria, where a significant subclass of Proteobacteria for removing phosphate and/or nitrate was found within a biofilm thickness of 0-250${\mu}m$. In addition, 16S rDNA clone libraries revealed that Klebsiella sp. and Citrobacter sp. were most dominant within the initial biofilm thickness of 0-250${\mu}m$, whereas sulfur-oxidizing bacteria, such as Beggiatoa sp. and Thiothrix sp., were detected in a biofilm thickness over 250${\mu}m$. The results of the bacterial community structure analysis using molecular techniques agreed with the results of the morphological structure based on scanning electron microscopy. Therefore, the overall results indicated that coliform bacteria participated in the nitrate and phosphorus removal when using the SBRBC system. Moreover, the structure of the biofilm was also found to be related to the EPS constituents, as well as the nitrogen and phosphate removal efficiency. Consequently, since this is the first identification of the bacterial community and structure of the biofilm from an RBC simultaneously removing nitrogen and phosphate from domestic wastewater, and it is hoped that the present results may provide a foundation for understanding nitrate and phosphate removal by an RBC system.

• Fisheries and Aquatic Sciences
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• v.4 no.3
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• pp.112-119
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• 2001

Aim of this research is to investigate the effect of temperature shocks on the physiological responses of cultured olive flounder (Paralichthys olivaceus) and black rockfish (Sebastes schlegeli). Olive flounder and black rockfish were suffered with high and low temperature shocks for 4 and 8h, respectively, in laboratory conditions and then the changes in glucose, lactate, total protein, uric acid, and triglycerides-glycerol in blood plasma were analyzed. We observed that lactate and uric acid increased for up to 4h and then decreased for up to 8h by the high and low temperature shocks, and total protein decreased for up to 4h and then recovered for up to 8h by the high temperature shock in both fishes. Glucose by the high and low temperature shocks and triglycerides-glycerol by the low temperature shock increased for up to 4h, and then decreased in olive flounder, but increased for up to 8h in black rockfish. From the result, we speculated that the two fishes have an interspecific variation in the regulatory systems of glucose and triglycerides-glycero1. Glucose would play important role as an energy source during the temperature shocks and for an intermediate substance for low temperature tolerance, and glycerol of triglycerides-glycerol would play an important role for low temperature tolerance. In olive flounder, the turnover of chemical change by temperature shock took more than 4h, all chemicals returned almost to the initial level for up to 8h, but fish death followed only in 8h with the high temperature shocked group within two days. Therefore, we suggested that fish would be damaged severely by the longer time exposure of high temperature and mortality would occur after a certain time later than the shocked time as a post-effect.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.43-46
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• 1981

The ratio of the eatable flesh taken from the filefish and its chemical components were investigated from March 1980 to February 1981 and the results are as follows :1. The ratio of the eatable flesh taken from the fish was low during March to June and high during July to December. 2. The moisture content was $81.4-82.0\%$ during March to June, $77.5-80.1\%$ during July to December and $79.4-81.4\%$ during January to February. 3. The protein content was $15.4-15.7\%$ during March to June, $17.0-19.9\%$ during July to December and $16.1-17.0\%$ during January to February. 4. The Lipid content was $0.31-0.41\%$ during March to January, $0.46-0.84\%$ during July to January and $0.43\%$ during February. 5. The carbohydrate content was $0.3-0.4\%$ during March to July, $0.5-0.7\%$ during August to January and $0.3\%$ during February. In conclusion, the ratios of the eatable flesh taken from the filefish and its protein content were highest during July to December in one year.

• Korean Journal of Ichthyology
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• v.7 no.2
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• pp.195-202
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• 1995

The seasonal changes in the muscle components of hibernant fish, amphibious mudskipper (Boleopthalmus pectinirostris), caught during the period between June 1993 and April 1994 were studied. The distributional changes of its major components in each muscle tissues was also observed before and after spawning and hibernation. Moisture content was the lowest after spawnig season and the highest just after hibernation, but crude protein was the highest after spawning sea-son. Crude lipid in female was the highest before spawning season, while in male it was the highest after spawning season, but both of female and male the lowest just after hibernation. Carbohydrate content in female and male showed the highest value just before hibernation and tended to decrease thereafter. In case of mudskipper, dyeing distribution was more or less spread in almost all of the tissues after spawning season but showed nearly no difference just after hibernation with the exception of small increase in dyeing degree of muco layer and epidermis layer. Investigation of mudskipper muscle tissue through the method of sudan black B dyeing yielded the results as follows ; lipid component in mudskipper in seasons before and after spawning season was percieved as mainly distributed in muco layer, epidermis and hypodermis layer respectively and also percieved a little between hypodermis subscutoneus cells. In season just before hibernation, it prevailed in almost all of the tissues, contrary to the weakness in its distribution degree just after hibernation.

• Development and Reproduction
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• v.21 no.2
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• pp.193-204
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• 2017

The influence of triploidization on histological characteristics of retina, trunk kidney, liver and midgut tissue, and cell cycle of tail fin and gill tissue in far eastern catfish, Silurus asotus were analyzed. In the infertile triploid fish, the nucleus and/or cell size of secondary proximal tubule cells of trunk kidney, hepatocyte and midgut epithelium are much larger than those of the corresponding cells in the diploid fish (P<0.05). However, triploid tissue showed fewer number of outer nuclear layer in retina and nuclei in secondary proximal tubule of trunk kidney than those for diploid tissue. The mean percentages of the $G_l-$, the S- and the $G_2+M-phase$ fractions were 92.5%, 3.2% and 4.3% in tail fin tissue of diploid, and 93.4%, 2.6% and 4.0% in those of triploid, respectively. There were no significant differences in the percentages of each cell cycle fraction between diploid and triploid. The mean percentages of each phase fractions were 75.1%, 11.1% and 13.8% in gill tissue of diploid and 85.2%, 8.9% and 5.9% in those of triploid, respectively. The differences of cell cycle between tail fin tissue and gill tissue were statistically significant in diploid and triploid (P<0.05). Also, the differences between diploid and triploid were statistically significant in tail fin tissue and gill tissue (P<0.05). Cyclin D1 and cyclin E expressions were not significantly difference between gill tissue and tail fin tissue, and protein expressions of induced triploid were higher than those of diploid. Results from this study suggest that some characteristics in the triploid exhibiting larger cell and nucleus size with fewer number of cell than diploid can be used as an indicator in the identification of triploidization and ploidy level in far eastern catfish.