• Animal cells and systems
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• v.14 no.3
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• pp.175-195
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• 2010

The genus Gonia (Diptera: Tachinidae) is revised for the Korean species. We recognize four previously known species (G. chinensis, G. divisa, G. foersteri, and G. klapperichi), three newly recorded species in Korea (G. distinguenda, G. olgae, and G. ussuriensis) and a species new to science (G. nigricoma Lee and Han, sp. nov.). We here provide a key, descriptions, photographs and illustrations. We also inferred the phylogenetic relationships of the representative Palaearctic species using cladistic method.

• Environmental Analysis Health and Toxicology
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• v.17 no.1
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• pp.7-11
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• 2002

Effects of nonylphenol (NP) on gonadal development and growth of olive flounder, Paralichthys olivaceus were investigated. NP treatment was carried out to fry fish (during 55 to 64 days after hatching) using oral adminstration at nominal NP concentrations of 50, 100 and 150 tig/g BW Gonad before NP treatment was sexually undifferentiated as observed with mostly gonia cells. At 159 days after hatching, ovarian lamella of ovary were filled with oogonia and perinucleolus oocytes. On the other hand, testicular lobules of the testis were occupied by spermatogonia, spermatocytes and spermatids. Histological observation of ovary and testis development was any different between the control and NP treated groups. However, growth was significantly increased in NP treated groups than control groups (P< 0.05). These results considerate that NP has any effect for sex differentiation and gonadal development, but act for early growth in olive flounder.

• Journal of Aquaculture
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• v.18 no.3
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• pp.167-172
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• 2005

Sex reversal to a functional male of sevenband grouper $(41.0{\pm}1.3cm\;TL,\;1.4{\pm}0.1kg\;BW)$ was induced by $17{\alpha}-methyltestosterone\;(MT,\;0.5\sim2.0mg/kg\;BW)$ implantation from March 17 to May 12,2002. Gonad of control group was composed of genial cells and peri-nucleolus oocyte during the experimental period. Gonad of fish treated with 0.5 mg MT/kg BW had peri-nucleolus oocytes, spermatogonia, spermatids and spermatozoa at the late stages of spermatogenesis, while the fish group treated with 1.0 and 2.0 mg MT/kg BW contained spermatoza in the efferent duct. Sperm were obtained from the experimental groups treated with a dose of $1.0{\sim}2.0mg$ MT/kg BW. In the MT treated groups, testosterone and 11-ketotestosterone levels were higher than those in the control group during the $2{\sim}6$ weeks of the experimental period (P<0.05). $Estradiol-17{\beta}$ was detected from fish in the experimental fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.373-377
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• 2000

This study Investigated the effects of $estradiol-l7{\beta} (E_2)$, $17{\alpha}-methyltestosterone$ (MT) and high temperature (WT) on gonadal sex differentiation in black rockfish, Sebastes srhlegeli. fish were reared to oral adminstration of E, at nominal concentrations of $20, 40 and 60 {\mu}g/g diet$, and MT at nominal concentration of 20 and $50 {\mu}g/g$ diet from 56 days to 77 days after parturition. In the treatment of WT, water temperature of the breeding tanks ranged $27.0{\pm}0.5^{\circ}C$ more than $10^{\circ}C$ approximately, in comparison to the control and other experimental group, In the process of sex differentiation until 56 days after parturition, gonads were composed of mostly gonia cells, sexually undifferentiated. In contrast, 128 dal's after parturition, the ovaries were composed of ovarian cavity and lamellae, and oogonia and perinucleolus oocytes were distributed in the lamellae of ovary, and the testes were composed of a number of seminiferous tubule, and spermatogonia were distributed in the seminiferous tubule, and also melanophore scattered in the matrix layer of testis. In the sex ratio, more females than male were observed from $E_2$. treatment groups when compared to the control, but more males than females were observed from MT and WT treatment groups when compared to the control. In the results of the present study, the concentration and kinds of the sex steroid hormones, and also the rearing high temperature caused to the factor of sex determination in the process of sex differentiation of black rockfish.