• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.277-286
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• 2001

Improvement and possible commercialization of a home-made electroporation apparatus(home-made) were further tried to establish a simple and effective introduction of foreign gene into sperm followed by in vitro fertilization. Expressions of introduced pJJ9 and pNT plasmids were shown in all fertilized eggs with electroporated spermatozoa. In particular, with this gene transfer system all the fry showed a consistently transient expression in the syncytium of the yolk sac. This fact is important since some required, minute quantity of human proteins can be produced from the established transient expression on the yolk sac of all fry derived from in vitro fertilization with electroporated spermatozoa. To explore tissue-specific expression in fish, which we will use a similar system later, we targeted the nerve tissue to see whether tissue-specific promoter is working in fish properly. pNT plasmid containing a nerve cell-specific tubulin promoter gene demonstrated consistently exact targeted expressions among the developing nerve cells in later stages of embryos and hatched fry. Finally, liver-specific genes are now being cloned by using already selected primers for useful human protein gene fusion.

• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.291-298
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• 2000

Vitellogenesis, an important reproductive process in oviparous animals, includes the processes of hormonally regulated synthesis of yolk precursor protein, vitellogenin (Vg), and their deposition in ovarian oocytes as a vitellin which is an important energy source as well as buoyancy regulator of the egg. Vg genes consist of a gene family that encompasses a large number of lipoproteins and produce different Mr. Vg proteins in liver. The expression of Vg is largely dependent on the estrogen, and both reproductive cycle and temperature also influence Vg synthesis. Synthetic estrogens or estrogenic pollutants was sufficient to induce Vg in both sexes of oviparous vertebrates. Therefore, the estrogenic induction of vitellogenesis in male has been used for biological marker in the screening of estrogenicity of certain endocrine disrupting compounds and the monitoring the world-wide contamination of estrogenic compounds in wild life. In the studies on the biological hazard and influence of endocrine disrupting chemicals using the Vg induction in oviparous males, it is important to consider the reproductive cycle, zoogeography and biodiversity of the wild life animals in Korea.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.126-127
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• 2005

• Development and Reproduction
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• v.10 no.3
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• pp.177-184
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• 2006

Retinol-binding protein(RBP) plays an important role in the specific transport of retinol to target cells through the blood stream in higher vertebrates. In order to clarify the effects of 4-nonylphenol(4-NP) on RBP mRNA expression in the rockfish, Sebastes schlegeli which is common in coastal waters of Korea and commercially important species, the cDNA library was constructed from the liver, and a partial fragment of the RBP gene was cloned. The deduced amino acid sequence from the RBP mRNA showed a high homology to the amino acid sequence from Sparus aurata(80%), Oncorhynchus mykiss(72%) or Anguilla anguilla(78%). Effects of 4-NP on RBP and vitellogenin(VTG) mRNA expression level in rockfish were examined by the northern blot analysis. In female and male rockfish injected with 4-NP(10 mg/kg BW, lower dose), there was no changes in the levels of VTG mRNA expression in the liver. The RBP mRNA levels, however, decreased at 48 hours after the injection in male. In the rockfish injected with 4-NP(25 mg/kg BW, higher dose), the level of VTG mRNA expression increased after 24 hours, regardless of sex. The level of RBP mRNA expression decreased at 48 hours after the injection in both sexes. These data indicate that estrogenic mimics such as 4-NP exhibit a contrasting effect on RBP and VTG gene expression in rockfish.

• Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.276-285
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• 2009

Despite great commercial interest, relatively little has been described about molecular mechanism of bivalve reproduction. We investigated genes involved in ovarian maturation of the Yesso scallop, Patinopecten yessoensis. GSI index and histological analysis revealed that maturation of ovary begin in February and spawning period is from April to June which is similar to the previous study in the East Sea. As result of combination analysis of differential display RTPCR (DDRT-PCR) and histological examination, vitellogenin (Vg), ferritin (Ft) and ADT/ATP carrier protein (ACC) were identified as differently expressed genes in maturating ovary. Endpoint RT-PCR results showed that Vg is ovary-specific genes whereas Ft and ACC are expressed ubiquitously suggesting that Vg can be good molecular markers for ovarian development and sex determination in bivalves. Quantitative PCR results revealed that Vg were expressed highest during growth stage and appears to play a major role in oocyte maturation. On the contrary, expression of Ft was highest after spawning stage, which suggests that up-regulation may be involved in spawning and inactive stages in which the scallops recover from spawning. In addition, high level of the mitochondrial gene, ACC, may play a role in energy metabolism in maturating oocytes. Isolation and molecular studies of these key genes will expand our knowledge of the physiological changes from various exogenous factors including temperature, salinity, pH, even or numerous endocrine disrupting chemicals (EDCs) during reproductive cycle. In addition, further study of these genes implicates various industrial applications including the stable seed production, increased food quality, or economic aquaculture system.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.65-77
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• 2006

Gene transcripts potentially responsive to the heat stress were surveyed by cDNA microarray analysis in mud loach (Misgurnus mizolepis). Transcriptional profiles of hepatic tissue in the fish exposed to either $23^{\circ}C$ or $32^{\circ}C$ for 4 weeks were compared each other by 3 replicated hybridization assays using 1,124 unigene clones selected from mud loach liver expressed sequence tags (ESTs). A total of 93 clones showed the substantially increased mRNA levels (>2-fold) in $32^{\circ}C$-exposed group when compared in $23^{\circ}C$control group. It includes various enzymes and proteins involved in energy pathway, protease/protein metabolisms, immune/antioxidant functions, cytoskeleton/cell structure, transport and/or signal transduction. Maximum level of increase was up to 15-fold relative to $23^{\circ}C$ treatment. Heat exposure also resulted in the significant decrease (less than 50% relative to $23^{\circ}C$-exposed fish) of the transcriptional activities in 85 genes. Besides the above categories, yolk protein (vitellogenin) and ribosomal proteins were notably down regulated in the fish exposed to heat stress. A number of novel gene transcripts were also detected in both up-regulated and down-regulated groups.

• Development and Reproduction
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• v.16 no.1
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• pp.9-18
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• 2012

The effects of the estrogenic compound 4-nonylphenol (4-NP) on vitellogenesis in juvenile olive flounder ($Paralichthys$ $olivaceus$) and rockfish ($Sebastes$ $schlegeli$) exposed continuously at 10, 50 and $100{\mu}g{\ell}^{-1}$ levels for 7 days were compared. The expression of VTG mRNA level and protein using specific probes were examined. The levels of plasma estradiol-17 ${\beta}(E_2)$ and testosterone (T) were assessed by radioimmunoassay (RIA). Plasma $E_2$ concentrations increased significantly in two female fish species exposed to $100{\mu}g{\ell}^{-1}$ of 4-NP over concentrations in control fish. Plasma T concentrations increased in $P.$ $olivaceus$. Four days after exposure, the level of VTG mRNA expression increased in $P.$ $olivaceus$ and $S.$ $schlegeli$ exposed to $20{\mu}g{\ell}^{-1}$ of 4-NP. In addition, plasma VTG protein expression was seen in $P.$ $olivaceus$ and $S.$ $schlegeli$. In $S.$ $schlegeli$ and $P.$ $olivaceus$ exposed to 4-NP, the changes were noticed mainly in hepatocytic vaculation after 7 days of exposure. Thus, 4-NP may disrupt vitellogenesis in immature fish both directly and indirectly via disrupted steroidogenesis and liver pathology. Immature $S.$ $schlegeli$ were the most sensitive to 4-NP exposure in vitellogenesis.

• Molecular & Cellular Toxicology
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• v.3 no.4
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• pp.267-272
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• 2007

Environmental and anthropogenic changes affect the health and stability of marine ecosystem. In this study we aimed to identify molecular biomarkers for ecotoxicological pollutants risk assessment in the rockfish (Sebastes schlegeli). We designed primers based on conserved sequences by multiple alignments of target genes from related species, and cloned the partial cDNAs of cytochrome P450 (CYP1A1), glutathione S-transferase (GST), metallothionein (MT), superoxide dismutase (SOD), ubiquitin (UB), vitellogenin (VTG) and $\beta$-actin by reverse transcription polymerase chain reaction (RT-PCR) from S. schlegeli. Northern blot results indicated that these six genes expressions were significantly induced by benzo[a]pyrene (BaP, 1 ${\mu}M$) and that the level of each of their transcripts increased in BaP-exposed rockfish in a time-dependent manner. This study suggests that transcriptional changes in these six genes may be used for monitoring environmental exposure to polycyclic aromatic hydrocarbons (PAHs).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.1
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• pp.17-22
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• 2022

Successful reproduction in vertebrates necessitates complex interactions along the brain-pituitary-gonad axis, it is determined by gonadotropin releasing hormone produced in the hypothalamus of the brain, gonadotropin synthesized in the pituitary gland, and sex hormone secreted by the gonads. The goal of this study was to secure and test technology for controlling (inhibiting) sexual maturation hormones such as maturation hormones through hormone regulation. We studied the effect on sexual maturation of zebrafish Danio rerio by tamoxifen, anastrozole, exemestane and dopamine 4 kinds of sexual maturation inhibitors to feed and after administration. As a result, 4 kinds of sexual maturation inducing substances were mixed with zebrafish feed, it could be concluded that all of them were effective in inhibiting sexual maturation by reducing mRNA levels of genetic materials related to sexual maturation.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.8
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• pp.1080-1088
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• 2013

Our previous results showed that kisspeptin-10 (Kp-10) injections via intraperitoneal (i.p.) once daily for three weeks notably promoted the egg laying rate in quails. In order to investigate the mechanism behind the effects of Kp-10 on enhancing the egg laying rate in birds, this study focused on the alternations of lipids synthesis in liver after Kp-10 injections. 75 female quails (22 d of age) were allocated to three groups randomly, and subjected to 0 (control, Con), 10 nmol (low dosage, L) and 100 nmol (high dosage, H) Kp-10 injections via i.p. once daily for three weeks, respectively. At d 52, quails were sacrificed and sampled for further analyses. Serum $E_2$ concentration was increased by Kp-10 injections, and reached statistical significance in H group. Serum triglyceride (TG) concentrations were increased by 46.7% in L group and 36.8% in H group, respectively, but did not reach statistical significance, and TG contents in liver were significantly elevated by Kp-10 injections in a dose-dependent manner. Serum total cholesterol (Tch) concentrations significantly decreased in H group, while in H group the hepatic Tch content was markedly increased. The level of non-esterified fatty acid (NEFA), apolipoprotein A1 and B (apoA1 and apoB) were not altered by Kp-10 injections. The genes expression of sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthetase (FAS), apolipoprotein VLDL-II (apoVLDL-II), cholesterol $7{\alpha}$-hydroxylase (CYP7A1) and vitellogenin II (VTG-II) were significantly up-regulated by high but not low dosage of Kp-10 injection compared to the control group. However, the expression of SREBP-2, acetyl-CoA carboxylase ($ACC_{\alpha}$), malic enzyme (ME), stearoyl-CoA (${\Delta}9$) desaturase 1 (SCD1), apolipoprotein A1 (apoA1), fatty acid binding protein 2 (FABP2), 3-hydroxyl-3-methyl glutaryl-coenzyme A reductases (HMGCR), estrogen receptor ${\alpha}$, ${\beta}$($ER{\alpha}$ and ${\beta}$) mRNA were not affected by Kp-10 treatment. In line with hepatic mRNA abundance, hepatic SREBP1 protein content was significantly higher in H group. Although the mRNA expression was not altered, the content of $ER{\alpha}$ protein in liver was also significantly increased in H group. However, SREBP-2 protein content in liver was not changed by Kp-10 treatment. In conclusion, exogenous Kp-10 consecutive injections during juvenile stage significantly advanced the tempo of egg laying in quails, which was associated with the significant elevation in hepatic lipids synthesis and transport.