• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.585-590
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• 2009

The purpose of this study was to examine the effects of oral-administered sex hormone for hybrid sturgeon, bester juvenile. The bester juveniles (2 months after hatching) were received a diet containing various doses of $17\alpha$-methyltestosterone (MT) or estradiol-$17\beta$ ($E_2$) for 6 months. Somatic growth of bester sturgeon juvenile did not show significant differences between experimental and control groups (27.9-30.5 cm; 125.1-161.7 g), although survival percentages showed a decreasing tendency in MT-treated animals. By histological examination, germ cells were recorded as smooth type in MT-treated fish and uneven type of germinal epithelium in $E_2$-treated animals. Their sex ratios were 5:4:1 (male: female: undifferentiation) in control and low dose of MT-treated fish (1 mg/kg), and 9:1:0 in fish treated with high dose of MT (10 mg/kg), whereas the ratios were reversed by both low and high doses of $E_2$ treatment, recorded as 2:8:0. Gonadal areas were not significantly differed in all trials (424,600.4 - 1,039,656.3 ${\mu}m^2$). Total number of germ cells, number of germ cells per gonadal areas and number of germ cells per area were significantly higher to 144.7-148.7 cells/section, 374.0-408.5 $cells/mm^2$ and 1,599.5-1,670.9 $cells/mm^2$ in $E_2$ treatment than those of others (30.4-63.9 cells/section, 148.4-226.9 $cells/mm^2$ and 850.0-1,050.6 $cells/mm^2$), respectively. And somatic growth according to their gender was not significantly differed between male and female.

• Development and Reproduction
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• v.23 no.1
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• pp.35-42
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• 2019

Fish shows great difference in growth rate between individuals during larval development and early growth. This difference seriously reduces the production efficiency in fish culture. Growth hormone (GH)/Insulin-like growth factor 1 (IGF1) system is said to play some pivotal roles in fish growth. In this study, we investigated differences of GH, IGF1 and GHR gene expressions in juvenile red spotted grouper (Epinephelus akaara) with different growth performance. Red spotted groupers were reared under the same environmental condition (water temperature $24{\pm}1^{\circ}C$, natural light) for 96 days after hatching. They were divided into 3 groups by size (fast growing, middle growing and slow growing groups: FGG, MGG, and SGG, respectively). RNA was extracted from the brain, liver and muscle tissues from each group, and target gene expression was examined by real-time PCR. In the brain with pituitary gland, expression of GH gene in FGG was significantly higher than the expression in SGG, but the expression of IGF1 and GHR genes in the muscle was highest in SGG. Difference of GHR and IGF1 mRNA in the liver between groups with different growth performance was less clear than that in other tissues, although level of IGF1 mRNA was higher in SGG than in MGG. These results suggest that hormonal governing of growth is not the same in fast growing and slow growing fish, and size grading could cause a shift of hormonal state and growth pattern in this species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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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.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.2
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• pp.409-414
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• 2017

Effects of human chorionic gonadotropin (HCG) on ovulation and spawning of the grass puffer, Takifugu niphobles, were investigated. Matured females spawned successfully by all doses of HCG. Spawning usually occurred 24 hours after hormone injection. Body weight of adult, gonadsomatic index (GSI), pseudo-GSI, body weight of spawned egg, success rate of spawn, fertilization rate, hatching rate, and survival rate of juvenile were correlated with increasing HCG doses. However, abnormal rate of juvenile was not correlated with increasing HCG doses. These results should be useful for developing aquaculture program of grass puffer.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.143-153
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• 2004

Non-spinning syndrome of Bombyx mori has been serious issue in sericulture industry near Kyungbuk area. This study was focused on the analysis of the mechanism and on screening candidate chemicals inducing the anti-metamorphosis of the silkworms. Rearing temperatures or initial body weight of the final instar larvae did not affect a normal larval to pupal metamorphosis of B. mori. However, pyriproxyfen (a juvenile hormone (JH) agonist) induced follicle patency significantly even at its 10$\^$-8/ M concentration and inhibited metamorphosis of B. mori in both developmental time and dose dependent manners. Pyriproxyfen induced JH esterase (JHE) activity and downregulated expression of JH binding protein of 5. mori. These results suggests that pyriproxyfen induced JHE activity as a JH agonist and that the elevated JHE activity degraded endogenous JH and resulted in JHBP gene expression. Based on the fact that the JH agonist induced follicle patency and inhibited metamorphosis of B. mori, follicle patency bioassay suggested that three commercial pesticides including simazine, molinate or alachlor were proved to give potent JH agonistic effect on B. mori. Further direct exposure experiments to these candidates are required to determine the chemicals responsible for the non-spinning syndrome of 8. mori.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.114-120
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• 1995

The effect of juvenile hormone analogue(JHA, Manina) on larval feeding duration, pupation ratio, cocoon weight, and cocoon shell weight in the present commercial parent and hybrid silkworm stocks were investigated. Topical applications of JHA on parent silkworm stocks were to prolong larval duration, but results of response on those stocks were not consistent. Especially the JHA on Jam 121, Jam 123 and Jam 138 did not play a role in larval duration, whereas that on Jam 114 was most effective in prolongation more than two days, compared with the controls. subsequent prolongation of feeding duration resulted in increase of cocoon weight and cocoon shell weight of most parent silkworm stocks, while Jam 114 showed decrease in cocoon weight and cocoon shell weight in spite of prolonged feeding duration of two days. Unlike the parent silkworm stocks, durations of feeding period in all hybrid silkworm stocks were prolonged about one day. Treatments of JHA on the hybrid stocks gave rise to increase of cocoon weight and cocoon shell weight, and especially were most effective in Sasung-jam, Eunbaek-jam and Samgwang-jam. Although treatments of JHA seemed to have no harmful effect on physiology of parent silkworm stocks as well as that of hybrid stocks, the JHA retarded pupation ratio of some parent silkworm stocks such as Jam 122, 131, 135 and 138 by about 10%.

• BMB Reports
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• v.44 no.6
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• pp.393-398
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• 2011

Polydnaviruses are a group of double-stranded DNA viruses and are symbiotically associated with some ichneumonoid wasps. As proviruses, the replication of polydnaviruses occurs in the female reproductive organ at the pupal stage. This study analyzed the effects of two developmental hormones, juvenile hormone (JH) and ecdysteroid, on the viral replication of Cotesia plutellae bracovirus (CpBV). All 23 CpBV segments identified contained a conserved excision/rejoining site ('AGCTTT') from their proviral segments. Using quantitative real-time PCR based on this excision/rejoining site marker, initiation of CpBV replication was determined to have occurred on day 4 on the pupal stage. Pyriproxyfen, a JH agonist, significantly inhibited adult emergence of C. plutellae, whereas RH5992, an ecdysteroid agonist, had no inhibitory effect. Although RH5992 had no effect dose on adult development, it significantly accelerated viral replication. The results of immunoblotting assays against viral coat proteins support the effects of the hormone agonists on viral replication.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.291-292
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• 2010

• YAKHAK HOEJI
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• v.28 no.1
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• pp.1-10
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• 1984

A total synthesis of dehydrojuvabione which has high juvenile hormone activity, is described. The kinetic enloate of mesityl oxide is used as nucleophilic synthon for this synthesis. 1,4-Dioxaspiro [4,5] decan-8-carboxaldehyde was treated with kinetic enolate of mesityl oxide to give 8-(1'-hydroxy-5'-methyl-3'-oxo-4'-hexenyl)-1,4-dioxaspiro [4,5] decane. The latter compound was dehydrated. The resulted dienone was treated with lithium dimethylcuprate. After that, appropriate transformation was performed to give dehydrojuvabione.

• Journal of Forest and Environmental Science
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• v.30 no.2
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• pp.218-225
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• 2014

Studies were carried out to standardize and develop a suitable macro-propagation technology for large scale production of superior clonal stock through stem cuttings in Commiphora wightii Arnott (Bhandari), a data deficient medicinal plant of arid region. For the purpose, three experiments were conducted. The first experiment was tried to elucidate the impact of various cutting diameters (0.50-0.75 cm, 0.75-1.00 cm, 1.00-1.50 cm, and >1.50 cm) in combination with varying growing conditions (sunlight, shade house and mist chamber) on shoot sprouting and rooting without using exogenous plant growth regulators. Cutting diameter (size 0.75-1.00 cm) in mist chamber has shown maximum sprouting (90.00%) and rooting (73.33%), primary root (6.67) and secondary root (16.67) followed by 1.00-1.51 cm in mist chamber. Minimum sprouting (40.00%), rooting (33.33%), number of shoot (1.33), primary root (1.00) and number of secondary root (1.00) was recorded in cutting diameter (size >1.50 cm) in sunlight. Second experiment was performed to find out optimum growth regulator concentration of rooting hormone (100, 200, 500 and 1000 ppm) of Indole-3-acetic acid (IAA) and Indole-3-butyric Acid (IBA) on adventitious root formation on cuttings diameter (size 0.25-0.50 cm) in comparison to control. Maximum rooting percentage (93.33%) was recorded in 200 ppm followed by 500 ppm (86.66%) of IBA as compared to control, which showed only 60 per cent sprouting. Third experiment was performed with newly formed juvenile micro-cuttings treated with varying concentrations of IAA and IBA. The juvenile cuttings (size 6-10 cm, basal dia <0.25 cm) were selected as micro-cuttings. The cuttings treated with IBA (500 ppm) showed 64.30% rooting as compared to other treatments. Results of above experiments indicate that cuttings (size 0.75-1.00 cm dia) may be developed in mist chamber for better performance. While using heavier cuttings, no growth promoting hormones is required however; growth regulator 200 ppm concentration of IBA rooting hormone was observed optimum for promoting macro-propagation in stem cuttings of lower diameter class (0.25-0.50 cm).