• 한국수산과학회지
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• 제48권4호
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• pp.447-453
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• 2015

We determined the optimal culture conditions for obtaining the maximum number of intestinal bacteria from the olive flounder Paralichthys olivaceus, and studied bacterial diversity using both culture-dependent and culture-independent methods. Using six culture conditions, mean bacterial numbers were greater than $10^6$ per gram of gut mucus, regardless of the medium. However, the bacterial diversity, based on colony morphology, appeared much higher on Marine agar (MA) and Zobell 2216 agar than on other media. We found eight and 17 cultured bacterial phylotypes with 99% minimum similarity in gut mucus grown on MA and tryptic soy agar, respectively. Furthermore, we used genomic DNA extracted from gut mucus to generate 78 random clones, which were grouped into 25 phylotypes. Of these, six were affiliated with Firmicutes, Actinobacteria, and Verrucomicrobia, and were not found using our culture-dependent methods. Consequently, we believe that Marine agar and Zobell 2216 agar are optimal media for culturing diverse intestinal microbes; we also discovered several novel sequences not previously recognized as part of the gut microbiota of olive flounder.

• Fisheries and Aquatic Sciences
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• 제2권2호
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• pp.167-171
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• 1999

This study was designed to develop biomarkers of coastal pollution using biochemical indices of flounder (Paralichthys olivaceus) by changes in lactate dehydrogenase (LDH) activity in the serum and cholinesterase activities in brain membranes. For this purpose acetylcholiesterase (AChE) activity, butyrylcholinesterase (BChE) activity, LDH/AChE ratio and LDH/BChE ratio of cultured flounders at 5 different sites on the southern coast of Korea were compared to those of wild flounders caught in the Pohang, eastern coast of Korea as a control group. Relatively high LDH activities were measured in the serum of flounders cultured on the southern coast of Korea (0.101-0.145 unit) than those in the Pohang control group (0.093 unit). AChE activities were significantly low $(about\;10-20\%)$ in brain membranes of cultured flounders compared to those in the Pohang control group. The ratios of LDH/AChE and LDH/BChE were consistently higher $(136-178\%,\; 155-214\%)$ in cultured flounders than those of Pohang control group. Thus, we propose that the ratios of LDH/AChE and LDH/BChE in flounders could be applicable for the diagnosis of marine pollution.

• Fisheries and Aquatic Sciences
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• 제7권3호
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• pp.171-173
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• 2004

Activity of acetylcholinesterase (AChE) is well known as a biomarker of exposure to organophosphate compounds in aquatic organisms. However, the effect of diethyl phthalate (DEP), a widely used plasticizer, on the chance of AChE activity is not yet known. Olive flounder (Paralichthys olivaceus) were exposed to DEP 300 and 1,000 mg DEP/kg b.w. through three times of intraperitoneal injection and effects were assessed in AChE activity of brain, muscle, heart and eyes of the exposed fish. AChE activity in various tissues of flounder was inhibited after exposure to DEP as a concentration-dependent manner, especially in brain, muscle and heart. Among tissues examined, heart is supposed to be a major part of body which is seriously damaged by DEP exposure. It indicates that DEP induces toxic effects in various organs (brain, muscle and heart), and changes of AChE activities. Such changed activities of AChE might be a useful biomarker to assess the impacts induced by phthalate esters including DEP.

• 한국수산과학회지
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• 제39권4호
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• pp.326-332
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• 2006

To investigate the effects of environmental salinity on the expression of the genes for growth hormone (GH) and prolactin (PRL) in the pituitary, and their receptors (GHR, PRLR) In the kidney, intestine, and gills in teleosts, we acclimated juvenile olive flounders (Paralichthys olivaceus) to different salinities (5, 15, 25, or 32 psu) for 3 days and examined their mRNA levels using the reverse transcription-polymerase chain reaction (RT-PCR). In the fish adapted to low salinity, the PRL mRNA levels in the pituitary were elevated dramatically, whereas the GH mRNA levels did not differ significantly. PRLR mRNA increased significantly in fish exposed to low salinity, whereas GHR mRNA levels did not differ. These results suggest that PRL is an important hormone for flounders that are acclimated to brackish water and it may control ion homeostasis with PRLR in the osmoregulatory organs.

• Fisheries and Aquatic Sciences
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• 제14권3호
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• pp.210-217
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• 2011

Olive flounder, Paralichthys olivaceus were exposed to waterborne Cu (control, 50, 80, 150, and 320 ${\mu}g$/L) for 30 days and then depurated for 20 days to investigate the effects of waterborne Cu exposure on growth, accumulation, and elimination. The weight-specific growth rate was significantly negatively related to waterborne Cu concentrations at 150 and 320 ${\mu}g$/L. The order of Cu accumulation in different tissues of exposed fish was liver>intestines>gills>kidneys>muscle, suggesting that the liver is more important than other tissues for the storage of Cu in olive flounder. The accumulation factor for the gills, intestines, liver, and muscle increased with increasing exposure time, and accumulation was negatively related to exposure concentration for the gills, kidneys, and muscle. Cu concentrations in the gills, intestines, and liver continuously decreased for 20 days of depuration. The fastest elimination rate occurred in the intestines at all exposure concentrations, and the order of Cu elimination in the different tissues was intestines>liver>gills.

• Fisheries and Aquatic Sciences
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• 제14권2호
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• pp.123-129
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• 2011

To determine whether rearing density affects the hypermelanosis on the blind side (ambicoloration) of olive flounders Paralichthys olivaceus, we reared fry with an unpigmented non-eyed (blind) side in duplicate at densities of 150 individuals/$m^2$ (commercial production density: control) and 450 individuals/$m^2$ (high density group) for 90 days in 1-t dark-green fiberglass reinforced plastics (FRP) tank. We recorded feed intake, feed conversion efficiency (FE), growth and survival, and measured the ratios of staining blind-side area (staining area) and ambicolored fish every 30 days. Daily feed intake (DFI), feed conversion efficiency (FE), growth rate, condition factors, and survival rate were calculated at the end of the experiment. Although the FE was higher in the high-density compared to the control, the two density groups showed similar feed intakes, growth, and survival. The ratio of staining area as well as the ratio of ambicolored fish significantly were significantly higher in the high-density group than in the control from days 30 to 60, but significantly increased and evened out by the end of the experiment (P<0.05). In conclusion, we determined that rearing density is not the main cause of the blind-side hypermelanosis, but found that increasing the rearing density can accelerate the ambicoloration in olive flounders.

• 한국수산과학회지
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• 제47권5호
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• pp.630-636
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• 2014

To investigate the characteristics of hybrid eggs and larva produced by olive flounder Paralichthys olivaceus females and starry flounder Platichthys stellatus males, we examined the developmental speed of hybrid eggs at different water temperatures. The developmental speed of hybrid eggs tended to increase with increasing water temperature. Specifically, the hatching times were 91 hrs, 62 hrs and 43 hrs at $10^{\circ}C$, $15^{\circ}C$ and $20^{\circ}C$, respectively. The mean biological minimum temperature of the hybrid was $1.3^{\circ}C$, which is in between that of the olive flounder and the starry flounder. In high water temperatureseasons, slower growth was observed in hybrids of the starry flounder which is a coldwater fish.

• Fisheries and Aquatic Sciences
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• 제5권4호
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• pp.295-301
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• 2002

Experiments were carried out to investigate the effects of metal interaction on the accumulation and elimination of Cd and Cu in the liver of flounder, Paralichthys olivaceus, exposed to sub-chronic Cd (0, 5, 10, 50, 100 ${\mu}g/L$)/Cu $(10 {\mu}g/L)$ mixture. Cd exposure resulted in an increased Cd accumulation in the liver of flounder for exposure periods and concentration, and Cd accumulation increased linearly with exposure time. Cu accumulation profiles were similar to those of Cd. Cd concentration in the liver significantly decreased at the 10th depuration period and elimination rate was $66.20\%,\;86.22\%$ in 50 and $100 {\mu}g/L$at the end of depuration periods, respectively. Although, Cu elimination was similar to Cd elimination phase, Cd elimination rate was higher than that of Cu. Co-relationship of Cd and Cu have a positive correlation coefficient r=0.8620 (P<0.001) and support the strong relationship between Cd and Cu accumulation. As increase with the Cd exposure concentration, there were significant (P<0.001) differences between Cd and Cu accumulation.

• Fisheries and Aquatic Sciences
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• 제7권2호
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• pp.70-75
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• 2004

The CMV promoter driven lacZ reporter gene (pcDNA-lacZ) was constructed and used for DNA immunization study. The expression of the lacZ gene was confirmed in vitro using RTG-2 cell line before using for in vivo study in olive flounder (Paralichthys olivaceus). In the dose response study, the maximum expression of the lacZ gene was found in the group injected with 5 ${\mu} g$ of the plasmid DNA. Kinetic study showed a significantly increased expression of $\beta-galactosidase$ gene at 7 days after injection. Effects of DNA vaccine on specific and nonspecific immune responses such as antibody and NO production were studied and the significant effect was found in olive flounder injected with 10 and 15 ${\mu} g$ DNA (sub optimal dose for lacZ gene expression). Two pro inflammatory cytokine genes, $IL-l\beta$ and $TNF-\alpha$, were also found to be up regulated in the muscle injected with the plasmid, suggesting an induction of local inflammatory response.

• 한국어병학회지
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• 제7권2호
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• pp.119-126
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• 1994

넙치의 면역반응에 수온이 미치는 영향을 조사하기 위하여 넙치에 포르말린 사균 Edwardsiella tarda 로 주사면역시킨 후 수온변화에 따른 체액성면역반응을 관찰하였다. 저수온 (12, $15^{\circ}C$) 에서 항체는 면역 2~3 주 후에 나타났으며 최대 항체가는 각각 16 과 32 이었다. 그러나 고수온(20, $23^{\circ}C$) 에서는 면역 1 주후에 나타났으며 최대 항체가는 약 2,048 로 높았다. 그리고 한번 형성된 항체는 수온의 변화에 민감하게 반응하였고 자연조건에서도 유사한 경향을 보였으며 면역지속기간은 19 개월 이상으로 나타났다.