• Journal of Marine Life Science
• /
• v.1 no.1
• /
• pp.41-49
• /
• 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 Animal Reproduction
• /
• v.16 no.3
• /
• pp.225-230
• /
• 1992

Many transgenic mice expressing human growth hormone gene were infertile. To investigate the infertility of these transfenic mice, it was looked into the estrus cycle and sexual behaviour and also tested through in vitro fertilization whether the germ cells of these mice normal or not. The infertile female transgenic mice were mated to the fertile males of ICR strain, but in almost all of them the vaginal plugs were not detected and their estrus cycles by vaginal smear were almost irregular which kept up estrus or diestrus stage. Many male transgenic mice did not have the ability of sexual behaviour. Therefore the viability of germ cells in infertile male transgenic mice was investigated by in vitro fertilization, but the sperm were normally fertilized with the eggs and the transgene of parent was passed on to the progeny. These results consequently suggest that the infertility of transgenic mice experssing human growth hormone gene may be due to the physiological activity of human growth hormone, not germ cells.

• Animal cells and systems
• /
• v.16 no.2
• /
• pp.135-144
• /
• 2012

$Dendronephthya$ $castanea$ Utinomi, 1952 is a member of the family Nephtheidae, and dominates shallow waters adjacent to the southern part of Jejudo Island, Korea. This species is a gonochoric internal brooder with a sex ratio of 1:1, and releases planulae around the time of the full and new moon from July to September, when the seawater temperature peaks. The gametogenic cycle is annual, and oogenesis (12 months) is longer than spermatogenesis (4-5 months). No difference in reproductive features including sexuality, sex ratio, gametogenesis and gametogenic cycles was found between the sympatric species $D.$ $castanea$ and $D.$ $gigantea$, and there was no temporal reproductive isolation. Investigation of the morphological taxonomy and molecular biology of these species indicates that they have very similar or identical traits, suggesting an absence of speciation and a need for taxonomic reclassification.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.1006-1010
• /
• 1995

This paper describes Sexual Reproduction Genetic Algorithm(SRGA) for function optimization. In SRGA, each individual utilize a diploid chromosome structure. Sex cells(gametes) are produced through artificial meiosis in which crossover and mutation occur. The proposed method has two selection operators, one, individual selection which selects the individual to fertilize, and the other, gamete selection which makes zygote for offspring production. We consider the effects of multi-selection and diploidy on search performance. SRGA improves local and global search(exploitation and exploration) and show optimum tracking performance in nonstationary environments. Gray coding is incorporated to transforming the search space and Genic uniform distribution method is proposed to alleviate the problem of premature convergence.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.1401-1403
• /
• 1996

A new method is proposed for tracking the optimum points in nonstationary problem via genetic search. Cache Pool to save the past genetic informations is added to population in search using Sexual Reproduction Genetic Algorithm(SRGA). In Cache Pool, elite chromosomes from population are accumulated. A best Individual is made up from these chromosomes in varying environment and inserted into the newly reproduced population every generation. Experimental results indicate changing global optima are accurately identified and followed.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.6
• /
• pp.992-996
• /
• 1997

Study on sexual dimorphism in Littorphism in Littorina brevicula should be interesting to examine that how the species prevent niche-overlap between the sexes? and how the species act differently in the reproductive roles of the sexes? Sexual dimorphism on the shell of L. brevicula was examined with 211 periwinkles larger than 5 mm shell length in Pusan, Korea. Sexual dimorphism was detected in the aperture length only. Aperture length of the female was longer than that of the male. A difference in the sexual role in the reproduction seems to be a probable explanation for the sexual dimorphism in the aperture length. The reproductive role of the male is to choose the best female and to transfer the sperm successfully by copulation, and the role of the female is to spawn their fertilised eggs into the seawater successfully. Perhaps females migrate to lower elevations on the shore than the males, so that they are submerged when they spawn. Because wave action at the lower area of the shore is stranger than that at the higher area on the shore, the females might need larger aperture size than the males to avoid dislodgement.

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

• Journal of Ecology and Environment
• /
• v.41 no.10
• /
• pp.281-289
• /
• 2017

Background: In this study, the growth and reproductive response of seedlings, grown in plastic pots with sand, to moisture and nutrients were analyzed in order to study the environmental conditions required to create an alternative habitat for Epilobium hirsutum L., an endangered plant. Results: Vegetative and reproductive growths of Epilobium hirsutum L. are accelerated with increase in moisture and organic matter content in the soil. Among vegetative organs, the number of runners related to asexual reproduction was the highest when the moisture content was over 25% and nutrient content between 7 and 14% in the soil. But the number of flowers related to flowering responses, among reproductive organs, was the highest when the moisture content was maintained at 75% and when nutrient content was 21% in the soil. The number of seeds, related to sexual reproduction, was the highest when the moisture content was over 25% and nutrient content between 14 and 21%. Conclusions: The study results show that a place with high moisture and nutrient content in the soil is advantageous to asexual and sexual reproduction of Epilobium hirsutum L. Therefore, we must serve periodically nutrient and seeds to sustain population in in situ conservation. Furthermore, it is advisable to create in riverside where abundant nutrient content have, making alternative habitat of Epilobium hirsutum L. Also, we must find species that have high contribution degree index through vegetation survey.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.1
• /
• pp.13-16
• /
• 2010

The effect of exogenous administration of tamoxifen (TAM) on hormonal profile and sexual maturity in Indian native Kadaknath (KN) fowl was investigated. Day-old chicks from the same hatch were randomly divided into 15 groups with 20 chicks in each group (5 treatments${\times}$3 replicates). The chicks were placed in battery brooders with wire-mesh floors and reared under uniform husbandry conditions (14 h light/d, 25-32${^{\circ}C}$) on a standard basal diet. At the age of two weeks (wk), birds from the control group ($T_{1}$) were injected with maize oil intramuscularly (I/M), whereas the other four experimental groups $T_{2}$, $T_{3}$, $T_{4}$ and $T_{5}$ were given tamoxifen (I/M) dissolved in maize oil at the rate of 0.5 mg (0.5 TAM), 1.0 mg (1.0 TAM), 2.5 mg (2.5 TAM) and 5.0 mg (5.0 TAM)/kg body weight, respectively, up to 30 wks on every alternate day. At every 6-wk interval, blood samples were collected from nine birds of each treatment group for estimation of estrogen and progesterone. The same birds were sacrificed for determination of the weight of ovary, oviduct, liver and adipose tissue. There was no significant difference in egg production traits except onset of lay and egg number. Low doses of TAM ($T_{3}$) advanced the onset of egg laying by 15 days over the control. Tamoxifen influenced the hormonal profile (estrogen and progesterone) in a dose dependent manner. However, higher doses of TAM suppressed ovary and oviductal growth. From this study, it may be concluded that lower doses of TAM enhanced sexual maturity while higher doses suppressed ovary and oviductal growth.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.16 no.3
• /
• pp.265-272
• /
• 1983

Carpogonia, spermatangia and carposporangia are demonstrated for North Atlantic plants of Audouinella alariae (Jonsson) Woelkerling for the first time. The plants are monoecious. Carpogonia are terminal on short branches and give rise to short trichogynes laterally. Spermatangia are usually borne in pairs on the supporting cells of carpogonia. Fertilized carpogonia give rise to 3-4 carposporangia. Morphology of sexual reproductive structures and postfertilization development provide characteristics for distinguishing A. alariae from A. rhipidandra (Rosenvinge) Dixon, which were previously synonymized.