• Journal of fish pathology
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• v.16 no.2
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• pp.111-118
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• 2003

Androgen plays an important role in the regulation of gonadotropin production in vertebrates . We have investigated the transcriptional pattern of androgen receptor (AR) in a variety of tissues in maturing male and female goldfish by RT-PCR. Specific primer for AR was designed based on goldfish AR gene from the GenBank (accession number AY090897). AR was shown 10 be maturity- and tissue-dependent gene expression pattern in goldfish. In immature male goldfish, significantly higher transcript level of AR was observed in the pituitary und testis , compared [0 brain and liver. Mature male goldfish showed a similar expression pattern to immature male goldfish. Interestingly. when compare to male goldfish, female goldfish showed AR mRNA expression that was found 10 be weak in pituitary, and very low expression in brain. They could not be found 10 have expression in any other tissues. Taken together. the- transcriptional analysis of AR depending on the tissue, sex. and maturity of a goldfish provides the opportunity for the study of goldfish reproductive physiology ,The results provided for the first time a comparison of the tissue distribution of AR mRNA in sexually maturating male and female goldfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.383-388
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• 2018

Goldfish hematopoietic necrosis (GHN) affects hematopoietic organs and causes high mortality in goldfish. The causative agent of GHN is cyprinid herpesvirus 2 (CyHV-2). The purpose of this study was to detect CyHV-2 in ornamental cyprinid fish. CyHV-2 monitoring was conducted on a monthly basis for 1 year using goldfish Carassius auratus and pearlscale goldfish Carassius auratus that had been cultured at a domestic aquafarm and imported from Singapore, respectively. The results of polymerase chain reaction (PCR) assays using specific primers for the CyHV-2 helicase gene showed that 27.8% of goldfish and 33.3% of pearlscale goldfish were positive for CyHV-2. No cytophatic effects were detected in koi fin or common carp brain cells inoculated with tissue homogenates from either fish. Our data provides the useful data for establishing future quarantine and disinfection policies.

• Journal of Life Science
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• v.22 no.8
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• pp.1046-1051
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• 2012

In order to investigate the changes in bioactive materials induced in goldfish brains by $^{18}F$ irradiation, the variations in the neurotransmitter levels in the whole brain were studied. The distance between the goldfish and 580 mCi of $^{18}F$ was about 4 cm, and the exposure lasted for 4 hrs. The absorption level calculated based on the distance, exposure time, and half-life of $^{18}F$ was approximately 2 Gy. After sacrifice by $^{18}F$ irradiation or untreated conditions, ten brains were dissected or immediately frozen, respectively. The tissues were extracted in acetic acid. After lyophilization, the samples were dissolved in distilled water and were further purified on a reverse-phase HPLC column. There were no differences in the intensities of the bioactive materials between $^{18}F$-exposed goldfish and control goldfish, while the only peak corresponded to 13 min, which indicated a significant increase in the irradiated brains. Our analysis has found that this compound is tryptophan. This result suggests that $^{18}F$ leads to changes in a classical neurotransmitter, tryptophan, in both the brains of control goldfish and goldfish contaminated by irradiation.

• Journal of Marine Life Science
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• v.1 no.1
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• pp.41-49
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• 2016

Kisspeptin (Kiss) and its cognate receptor, kisspeptin receptor (KissR; G protein coupled receptor 54, GPR54), have recently been recognized as potent regulators of reproduction in teleosts. Additionally, leptin plays an important role in energy homeostasis and reproductive function in teleosts. The purpose of this study was to examine differences in the concentration of the hormones of the Kiss/KissR system and leptin and the expression of their underlying genes, all of which are involved in the sexual maturation of female goldfish, Carassius auratus, following treatment with Kiss. The expression levels of KissR increased after the Kiss injection. Furthermore, the peptide hormone leptin also increased after the injection (in vivo and in vitro). Additionally, the expression of GnRH and GTHs (GTHα, FSHβ, and LHβ) increased in the brain and pituitary (in vitro and in vitro). These results support the hypothesis that Kiss plays important roles in the direct regulation of the hypothalamus-pituitary-gonad axis and leptin in goldfish. Therefore, we suggest that Kiss system gene expression is correlated with energy balance and reproduction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.5
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• pp.286-290
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• 2005

Oxytocin (OT)-related peptide, isotocin was purified from the brain extract of conger eel (Conger myriaster) using reverse-phase, ion-exchange and size exclusion high performance liquid chromatography (HPLC). The sequence of the peptide, with a molecular weight of 967.30 Da, was determined as Cys-Tyr-Ile-Ser-Asn­Cys-Pro-Ile-Gly-$NH_2$, where the Cys between 1st and 6th residues made an intramolecular disulfide bridge by the automated amino acid sequence analysis and MALDI-TOF mass spectrometry. The sequence was confirmed by identical elution with the purified and synthetic peptide using the HPLC system. As a result of homology investigation, the primary structure of this peptide was the same as that of OT -superfamily member, isotocin. The synthetic peptide showed a contractile activity at a minimal effective concentration of $10^{-7}M$ on the intestinal smooth muscle of goldfish (Carassius auratus).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.1
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• pp.6-11
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• 2005

Vasopressin (VP)-related peptide was purified from the brain extract of conger eel (Conger myriaster) by reverse-phase, ion-exchange high performance liquid chromatography (HPLC). This peptide with a molecular weight of 1,051.2 Da was determined as $H-Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Arg-Gly-NH_2$, whose Cys residues made an intramolecular disulfide bridge by the automated amino acid sequence analysis, MALDI- TOF mass spectrometry. It's sequence was confirmed by identity of the elution position with the synthetic peptide in HPLC system. As a result of homology investigation, the primary structure of this peptide was the same as that of VP-superfamily member, $[Arg^8]-vasotocin$. The synthetic peptide showed a contractile activity at a minimal effective concentration of $10^{-10}\;M$ on the intestinal smooth muscle of goldfish.