• Journal of Aquaculture
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• v.12 no.2
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• pp.91-100
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• 1999

The complete nucleotide sequence of olive flounder (Paralichthys olivaceus) hsp70-related rDNA was determined by RT- and RACE-PCR methods. A full-length of hsp70-related cDNA has an open reading frame of 1.95 kb encoding 650 amino acids with a calculated molecular weight of 71.1 kD. A corresponding hsp70-related protein contains a number of conserved elements including an ATP-binding domain, a nuclear localization signal and the carboxyl terminal motif, EEVD, which may have a role in chaperone function. Comparison of nucleotide and predicted amino acid sequence between olive flounder hsp70-related gene and hsp/hsc70 genes of other species revealed a high similarity with the cognate form of these genes. These results indicated that we recovered likely to be a olive flounder cognate hsc70 gene.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.4
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• pp.239-244
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• 2005

The effects of diluents composition on cold storage for olive flounder (Paralichthys olivaceus) sperm were examined in terms of the swimming speed of sperm, the percentage of mobile sperm, and fertilization rates. The following results indicated that cold storage methods with fresh conditions could be employed in olive flounder milt preservation. The preserved sperm of olive flounder that was diluted I: 10 with artificial seminal plasma II (ASP II) and Stein's solution (SS) at $0^{\circ}C$ remained motile for 30 days. The most effective condition for cold storage was ASP II and SS at 0 $0^{\circ}C$ for the sperm, although there is no significant difference statistically. No difference in the fertilization rate was found between fresh sperm and the preserved ones with ASP I, II and SS at 10 days post-storage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.23-30
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• 2018

Kudoa septempunctata, a myxosporean parasite that infects olive flounder Paralichthys olivaceus is known to cause Kudoa food poisoning. Entire trunk muscle (ETM) is used for diagnosis of the parasite in fish and this method demands sacrifice of the host, causing a loss of commercial value. We developed a non-destructive method that uses a plastic syringe-style implanter to draw the sample, called the part-point muscle (PPM) sampling technique. We validated the PPM method in fish infected with K. septempunctata at the level detectable by the ETM method. We confirmed that the PPM method is equally sensitive in comparison to the ETM method for diagnosing K. septempunctata spores in olive flounder muscle. Our study also confirmed that the parasite is uniformly distributed in the dorsal muscle of infected fish. Over a period of 1 month, we observed no mortality of the host fish used for sampling by the PPM method. Thus, our studies demonstrate that the PPM sampling technique is an efficient, non-destructive method for diagnosing K. septempunctata in olive flounder.

• Fisheries and Aquatic Sciences
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• v.10 no.1
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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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• v.15 no.3
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• pp.233-239
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• 2012

Hematological analysis can provide crucial information for monitoring the health of fish. However, there is no current information available regarding hematological changes in olive flounder following infection by Vibrio scophthalmi. In this study, hematological and biochemical alterations were determined in olive flounder infected by the high virulence strain (HVS) and low virulence strain (LVS) of V. scophthalmi. Survival in serum, skin mucus, and macrophages of olive flounder was also compared between the HVS and LVS. The results demonstrated that the hematocrit value in infected fish declined from 23.4% at 0 h to 18.0% at 168 h post infection. The total protein concentration in fish infected with the HVS was significantly higher than in fish infected with the LVS and a non-infected control. Lysozyme activity was significantly different between infected and control fish. The HVS survived in serum and cell numbers increased substantially, while cell numbers of the LVS in serum decreased. These changes in hematological characteristics in fish infected by V. scophthalmi can be used as an effective and sensitive index to monitor the physiological and pathological conditions of fish. The survival and reproduction of V. scophthalmi in host serum, skin mucus, and macrophages play a major role in systemic infection and can serve as a virulence indicator for different strains.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1828-1833
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• 2016

The purpose of this research was to investigate the bacterial flora of healthy olive flounder larvae (Paralichthys olivaceus) and live feeds (Rotifer spp. and Artemia spp.). The total bacteria counts were $9.2{\times}10^7$ and $1.2{\times}10^{10}cfu/g$ and Vibrio sp.(82.8%) was dominant in rotifers. The total bacteria counts were $3.8{\times}10^6$ and $9.2{\times}10^6cfu/g$ and Vibrio sp.(73.3%) was dominant in artemia. In olive flounder larvae, the total bacteria counts were $1.4{\times}10^6{\sim}8.3{\times}10^7cfu/g$ and V. harveyi (38.5%) was dominant. It might be potential marker of disease outbreak in olive flounder larvae.

• Development and Reproduction
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• v.23 no.1
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• pp.55-61
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• 2019

To develop a promoter capable of driving transgene expression in non-model fish, we identified and characterized the muscle-specific alpha-actin gene in olive flounder, Paralichthys olivaceus (PoACTC1). The regulatory region of PoACTC1 includes putative regulatory elements such as a TATA box, two MyoD binding sites, three CArG boxes, and a CCAAT box. Microinjection experiments demonstrated that the regulatory region of PoACTC1, covering from -2,126 bp to +751 bp, just prior to the start codon, drove the expression of red fluorescent protein in developing zebrafish embryos and hatching olive flounder. These results suggest that the regulatory region of PoACTC1 may be useful in developing a promoter for biotechnological applications such as transgene expression in olive flounder.

• Parasites, Hosts and Diseases
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• v.57 no.4
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• pp.439-444
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• 2019

Since Kudoa septempuntata was identified as a causative agent of food poisoning associated with raw olive flounder Paralichthys olivaceus, interest and concern regarding the parasite have increased. However, there have been no investigations or reports of other Kudoa species infecting the fish (except for K. paralichthys, which infects the brain) in Korea. We found cysts filled with myxospores of Kudoa species in muscles of cultured olive flounder specimens and identified these to the species level. Mature spores were quadrate, measuring $8.7{\pm}0.5{\mu}m$ in length, $9.2{\pm}0.4{\mu}m$ in thickness, and $12.9{\pm}0.6{\mu}m$ in width. The spores containing 4 polar capsules had a length of $2.1{\pm}0.2{\mu}m$ and a width of $1.8{\pm}0.3{\mu}m$. The partial 18S and 28S rDNA of isolates showed 99-100% similarities with K. ogawai. Using these morphological and molecular analyses, the species was identified as K. ogawai. This study is the first report of K. ogawai infection in cultured olive flounder in Korea.

• Journal of fish pathology
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• v.31 no.2
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• pp.101-107
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• 2018

Quantitative analysis of a myxosporean parasite, Parvicapsula sp. in internal organs (kidney, intestine, spleen, brain and liver) from non-emaciated (farm-A) or emaciated (farm-B and farm-C) olive flounder Paralichthys olivaceus were performed by real-time PCR. The highest DNA copy number ($1.7{\times}10^7copies/mg$ tissue) was detected in kidney of the emaciated olive flounder from farm-C, while the DNA copy number was below detection limit in all the organs of the olive flounder from farm-B. There was not positive result in all of organs from olive flounder in farm-A. PCR and histopathological analysis were also performed using the same specimen and showed same results as those by real-time PCR.

• Journal of fish pathology
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• v.31 no.2
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• pp.123-129
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• 2018

Parvicapsula anisocaudata, a myxosporean parasite, is presumably one of causative agents of emaciation in olive flounder Paralichthys olivaceus in Korea. In this study, we report a case of unusual abdominal distension due to exceptionally enlarged liver in farmed olive flounder. For the identification of the causative agent, bacteria and nucleic acids of virus that are possibly present were attempted to isolate from internal organs of five fish sampled from a fish farm in Jeju. Although a few bacterial colonies were isolated from some samples, there was no evidence that fish were primarily affected by virus and/or bacteria. From histopathological analysis, myxosporean were found in almost all internal organs, particularly in the stomach. The causative agent was identified as P. anisocaudata by sequencing a part of small subunit rRNA. This study contains a very unusual case of olive flounder heavily and systemically infected with P. anisocaudata, showing excessively enlarged liver with a small amount of ascitic fluid.