• Fisheries and Aquatic Sciences
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• 제10권1호
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• pp.8-15
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• 2007

Rhodopsin, a dim-light receptor, is a model system for the study of G protein-coupled receptors that transduce extracellular signals into cells. To study the molecular mechanisms of visual systems in fish, the rod opsin gene of olive flounder Paralichthys olivaceus was characterized. The full-length P. olivaceus opsin gene was obtained by PCR amplification of genomic DNA, as well as cDNA synthesis. A comparison of clones obtained from both methods indicated that the olive flounder rod opsin gene lacks introns. Sequence analysis of the opsin gene indicated that it contains a 1,056-bp open reading frame encoding 352 amino acids. The deduced amino acid sequence contains features of typical rod opsins, such as sites for Schiff's base formation (K296) and its counterion (E113), disulfide formation (C110 and C187), and palmitoylation (C322 and C323). An opsin sequence alignment showed the highest similarity between P. olivaceus and Solea solea (95.1%), followed by Hippoglossus hippoglossus (94.5%). An opsin phylogenetic tree revealed a close relationship between olive flounder and teleost rod opsins.

• Fisheries and Aquatic Sciences
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• 제8권3호
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• pp.132-137
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• 2005

Olive flounder (Paralichthys olivaceus) is one of the most commercially important species of farmed marine fish in Korea. Although techniques for rearing the larva of this species are improving, production costs are also increasing due to microbial influences and genetic degradation caused by successive culturing. Since the demand for healthy seed, which requires eggs of good quality of, is high, we examined the effects of nutrient composition on the size of P. olivaceus eggs. We analyzed floating (live) and sunken (dead) eggs of P. olivaceus from five different hatcheries for their size and amino and fatty acid composition. The sizes of eggs and oil globules from floating vs. sunken eggs were significantly different at p<0.05. No significant relationships were observed, however, among larval length, hatching percentage, and egg and oil globule size. The dry weight and amino acid levels of floating eggs were greater than those of sunken eggs (p<0.05), but no difference in fatty acid content was observed.

• Fisheries and Aquatic Sciences
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• 제6권2호
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• pp.101-104
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• 2003

A cDNA clone for the olive flounder (Paralichthys olivaceus) transferrin receptor (fTfR) was isolated from a leukocytes cDNA library. The fTfR gene consisted of 2,319 bp encoding 773 amino acid residues. The amino acid sequence alignment of the fTfR showed that their size and hydrophobic profile are similar. In addition, the Tyr-Thr-Arg-Phe (YTRF) motif that is the recognition signal for high-efficiency endocytosis, is conserved very well. This motif is important for functional properties of TfR. The deduced amino acid sequence had $42.4-42.9\%$ identities with the previously reported TfRs of vertebrates. The fTfR was expressed in the blood, kidney, spleen, and liver of healthy olive flounder by the Northern blot hybridization.

• Fisheries and Aquatic Sciences
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• 제4권1호
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• pp.25-31
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• 2001

4-Aminobutyrate aminotransferase plays an essential role in the 4-aminobutyric acid shunt, converting 4-aminobutyrate to succinic semi aldehyde. We isolated and sequenced' a fish cDNA fragment that encodes 4-aminobutyrate aminotransferase. A brain cDNA library from flounder (Paralichthys olivaceus) was constructed using the ZAP- III XR vector and screened for the fish 4-aminobutyrate aminotransferase gene using a probe derived from the conserved sequences of known mammalian 4-aminobutyrate aminotransferases. A partial cDNA for 4-aminobutyrate aminotransferase was cloned and found to be 700 bp in length corresponding to 66 amino acids. Nucleotide sequence of the clone was aligned with NCBI (National Center for Biotechnology Information) DNA sequence data base. The result showed high sequence identity with previously reported mammalian 4-aminobutyrate aminotransferases. The trans­criptional level of flounder 4-aminobutyrate aminotransferase was detected with the presence of mRNA at different flounder tissues by reverse transcription-polymerase chain reaction (RT-PCR). The expression of flounder 4-aminobutyrate aminotransferase was also tested and detected from the flounder tissues of the brain, liver, kidney and pancreas.

• Fisheries and Aquatic Sciences
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• 제6권4호
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• pp.225-227
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• 2003

Acetylcholinesterase (AChE) activity is a potential biomarker for phenanthrene exposure in aquatic organisms. Olive flounder (Paralichthys olivaceus) were exposed to three different concentrations (0.5, 1.0 and 2.0, uM) of phenanthrene for four weeks. AChE activities in the brain, heart and eyes were documented. Inhibition of AChE activity was found significant in flounder treated with a concentration greater than $1.0 {\mu}M$ of phenanthrene. This indicates that a chronic exposure to phenanthrene induces damage in various organs (brain, heart and eyes) and changes of AChE activities might be a useful biomarker to assess the impacts induced by polycyclic aromatic hydrocarbon (PAH). Evidence from this study confirms that the measurement of AChE in the brain and eyes of flounder is a valuable tool that along with other biomarkers can maximize an ecotoxicologists' confidence in assessing the impacts of oil and PAH pollution in the aquatic environment.

• 한국양식학회지
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• 제16권2호
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• pp.99-103
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• 2003

Olive flounder (Paralichthys olivaceus) was exposed to water-borne phenanthrene for 4 weeks. After the exposure for 2-weeks, hepatic cytochrome P450 contents were significantly elevated. Induction of hepatic ethoxy resorufin-O-deethylase (PROD) activity was significantly increased in flounders treated with 1.0 and 2.0 $\mu$M phenanthrene, compared to untreated group and 0.5 $\mu$M treated group. However, there were no significant changes in pentoxyresorufin-O-deethylase (PROD) activity in hepatic microsome of all the phenanthrene-treated groups, compared to the untreated group. Phenanthrene has the potential to induce cytochrome P450 and EROD enzyme of the olive flounder.

• Ocean and Polar Research
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• 제32권4호
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• pp.483-488
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• 2010

Since 2000 fry releasing programs in Korea have significantly expanded in order to support the commercial fishing industry through recruitment enhancement of targeted species. Here we investigate the economic effectiveness of the Olive flounder (Paralichthys olivaceus) fry releasing program in Korean waters. The market survey method was used in our analyses. Results show that the B/C ratio, as an indicator of economic evaluation, is 2.56 in the East Sea region, 9.45 in the South Sea region, and 1.34 in the West Sea region, which indicates that the fry releasing program is economically feasible but the economic effectiveness varies from region to region.

• Animal cells and systems
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• 제8권4호
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• pp.329-333
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• 2004

Japanese flounder (Paralichthys olivaceus) head kidney (HK) leukocytes were incubated with $10^3$ to $10^{-3}$ ng levamisole/ml for 4, 24 or 48 h and then assayed for their natural cytotoxic activity against xenogeneic tumor cells. This activity was slightly increased after 24 h of incubation. In a second experiment, fish were fed 0, 75, 150 or 300 mg levamisole/kg diet for 10 consecutive days. The fish were then fed a commercial non-supplemented diet and sampled 0, 1, 2, 3, 4 or 6 weeks post-administration of levamisole. The cytotoxic activity was found to be increased with increasing levamisole dose and remained greatly enhanced until the end of the experiment. In conclusion, levamisole enhanced flounder natural cytotoxic cell activity both in vitro and in vivo and had a great lasting action when administered by feeding.

• Fisheries and Aquatic Sciences
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• 제7권1호
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• pp.29-33
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• 2004

The potential of phenanthrene to induce xenobiotic responses was investigated. Olive flounder (Paralichthys olivaceus) was exposed to different levels of phenanthrene $(0.5,\;1\;and\;{\mu}M)$ for 4 weeks, Gill CYP450 content and EROD (ethoxyresorufin O-deethylation) activity were found to be significant in the flounders treated with the higher concentration of phenanthrene $(>1.0\;{\mu}M)$, however, there were no significant changes in gill PROD (penthoxyresorufin O-deethylation) activity in all treated group compared to the controls. This study demonstrated that phenanthrene has potential to induce gill cytochrome P450 and EROD enzyme in olive flounder.

• Fisheries and Aquatic Sciences
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• 제15권3호
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• pp.215-220
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• 2012

The effects of inorganic mercury on hematological parameters and hepatic oxidative stress enzyme activity were studied in olive flounder Paralichthys olivaceus. Fish were injected twice intraperitoneally with mercuric chloride (2, 4, or 8 mg Hg/kg BW). The major hematological findings were significant decreases in the red blood cell count, hematocrit value, and hemoglobin level in olive flounder exposed to 8 mg Hg/kg BW. Remarkably low levels of calcium and chloride, and reduced osmolality, were also observed at 8 mg Hg/kg BW. In hepatic tissue, significant increases in glutathione peroxidase and catalase activity were observed above 4 mg Hg/kg BW Inorganic mercury also increased glutathione S-transferase and glutathione reductase activity at 8 mg Hg/kg BW in hepatic tissue. The present findings suggest that exposure to a low concentration (${\geq}4$ mg Hg/kg BW) of inorganic mercury can cause significant changes in hematological and antioxidant parameters.