• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.557-562
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• 1995

In this study, characteristics of chick primordial germ cells (PGCs), which is the founder cell of the germline, and gonadal development of the chick embryo between 12hrs and 6 day of incubation were investigated by transverse serial sections of chick embryos under the light microscopic observation. In embryo stage 20 (3 day of incubation), there are a lot of PGCs at the mesenchym, which were moving to the thickened epithelium (gonadal ridge). The PGCs arrive at both right and left gonad primordial in equal number prior to stage 24 (4 day of incubation), but in the following stages, the distribution of the PGCs became asymmetrical. More PGCs colonized the left than the right gonad, but the reason for the unequal distribution of PGCs is uncertain. The PGCs have mostly settled in the gonadal ridge (GR) at 6 day embryo. This study was conducted to investigate characteristics of the PGC migration and gonadal formation and observe the best condition for PGC isolation, culture and to attempt the possibility of the production for transgenic germline chimeras with manipulated PGCs.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.12-18
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• 1998

Tremendous progress has been made over the past quarter-century studying the genetics of gametogenesis and the resulting gametes and embryos. Studies merging molecular techniques and conventional cytogenetics are now beginning to bridge the gap between what we have learned about the meiotic process in males and females and what we know of the mitotic chromosomes of zygotes. Numerical abnormalities in sperm, oocytes and embryo can now diagnosed by fluorescence in situ hybridization (FISH). "At risk" couples can, therefore, have only unaffected embryos replaced in the sterus and avoid the possibility of terminating a pregnancy that might only be diagnosed as affected later gestation. Single-cell genetic analysis has also provided powerful tools for studying genetic defects arising during early human development. Recent studies of sperms, oocytes and cleavage-stage human embryos have revealed an unexpectedly high incidence. These genetic abnormalities are likely to contribute to early pregnancy loss and have important implications for improving pregnancy rates in infertile couples by assisted reproduction. The widespread use of preimplantation genetic diagnosis (PGD) awaits further documentatio of safety and accuracy. Other issues also must be addressed. First, the ethical issues regarding germ cell and embryo screening must be addressed including what diseases are serious enough to warrant the procedure. Another concern is the use of this technology for non-genetic disorders such as gender selection. Finally, the experimental nature of these procedure must continually be discussed with patients, and long-term follow-up studies must be undertaken. Development of more accurate and less expensive assays coupled with improved assisted reproductive technology success rates may make PGD a more widely use clinical tool. The future awaits these development.velopment.

• 대한생식의학회:학술대회논문집
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• 2003.12a
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• pp.123-124
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• 2003

• Journal of Embryo Transfer
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• v.8 no.2
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• pp.143-149
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• 1993

The objective of this study was to produce calves derived from in vitro fertilization of in vitro matured follicular oocytes. Oocytes aspirated from small antral folicles of ovaries obtained at a local slaughter house were matured and fertilized in vitro. At l8hrs after insemination with Korean native cattle semen, oocytes were co-cultured for 6~7 days by utilizing co-culture system with bovine oviduct epithelial cell. After co-culture, good or excellent quality late morulae or early blastocysts were selected by morphological criteria under stereo microscope. Selected embryos were transferred to recipients on day 6 or 7 (estrus = day 0). Recipients were monitored by observation for estrus and rectal palpation after 60 days from embryo transfer. One of them went to term with the birth of a calf. This case is the first production of calf derived from in vitro fertilization in Korea.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2005.10a
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• pp.91-91
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• 2005

• Journal of Embryo Transfer
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• v.12 no.3
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• pp.247-251
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• 1997

This research was conducted to observe developmental capacity of the early embryos aggrigated to phytohemagglutinin-M(PHA-M) in the culture of mouse embryos in vitro. The results showed that the development of blastocyst increased to 2-celT >< 2-cell : 68. 9%, 4-cell $\times$4-cell : 92.5% and 8-cell $\times$8-cell : 97.3% in the aggrigated embryos of ICR mouse, and 2-cell $\times$ 2-cell : 90.0%, 4-cell $\times$4-cell : 93.9% and 8-cell $\times$ 8-cell : 100% in the aggrigated embryos of two different strains (ICR $\times$ CBA/J mouse). (Key words : aggrigated embryos, in vitro 2-cell block, phytohemagglutinin-M, blastocyst)

• Journal of Embryo Transfer
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• v.32 no.4
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• pp.275-285
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• 2017

Lysophosphatidic acid (LPA) is an important signaling molecule. Here, the effect and mechanism of LPA on the preimplantation development of porcine embryos during in vitro culture (IVC) was examined. Porcine embryos were cultured in porcine zygote medium (PZM-3) supplemented with $30{\mu}M$ LPA during different days. There was a significantly higher cleavage rate in Day 1-7 and significantly higher total cell number of blastocysts in Day 1-3 and Day 4-7. It was also found that messenger RNA (mRNA) expression level of PCNA, BCL2 and BAX in blastocysts obtained from D1-7 group were significantly higher and BCL2/BAX mRNA ratio in D1-3 group was significantly lower than control group but Day 4-7 and Day 1-7 groups were comparable with control group. Treatment with $20{\mu}M$ PLC inhibitor significantly decreased the embryo cleavage rate and blastocyst formation rate. Moreover, LPA as an activator of PLCs, enhanced the $30{\mu}M$ LPA + $20{\mu}M$ U73122 group embryo cleavage rate which similar with control group. In conclusion, the results suggest that treatment with LPA during IVC improves the porcine early embryo cleavage by activation of PLC signaling pathway and regulate the mRNA expression that contribute to total cell number of blastocysts during blastocyst formation.

• Korean Journal of Plant Resources
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• v.18 no.2
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• pp.302-308
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• 2005

This study was carried out to obtain the basic informations on the characteristics of gametophytes formation and embryo developement in Dicentra spectabilis. Microspore mother cells developed from archesporial cells, start meiosis when flower bud length reaches around 1 mm, formed tetrahedral type tetrad. The 4 microspores were separated. They were developed to male gametophytes, respectively. Megaspore mother cells were observed when flower bud length was $4{\sim}5\;mm$. The developemental type of megaspore was polygonum and embryo sac was amphitropous. Three large and distinctive antipodals did not degenerated and remained after embryo sac was developed. When the male and female gametophytes was fully developed, the length of stamen and style was very similar or stamen was shorter about 0.5 mm than that of style. This result indicates that self-fertilization can be occurred in this species. After fertilization, developing zygotic embryos showed various stages of development from globular to cotyledonary embryos, and zygotic embryo in seed scattering time seemed to have an early cotyledonary stage.

• Journal of Embryo Transfer
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• v.31 no.2
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• pp.123-129
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• 2016

This study is performed to evaluate the effect of insulin in the porcine parthenogenetic embryo development. In porcine embryo culture, insulin is helpful factor in the process of embryo development. To identify this, insulin is used in pig embryos development. Therefore, this study was performed to investigate the effect of insulin on early embryonic development in pigs. For that, insulin positive or negative (0, 10 ug/mL) was supplemented in the porcine IVM media and then compared two groups divided by the cytoplasm of the black groups and white ring groups based on the distribution of lipid material of the cell cytoplasm in microscope. In maturation rates of porcine oocytes, significant higher black group rates were shown in the insulin positive groups compared with other groups ($56.0{\pm}2.1$ vs $46.2{\pm}0.3$). In the embryo culture, black groups were showed the significant higher cleavage rates ($82.1{\pm}0.8$, $78.3{\pm}0.1$ vs $63.2{\pm}0.3$, $63.4{\pm}0.0$), and blastocyst formation rates ($15.5{\pm}3.6$, $16.6{\pm}0.4$ vs $11.7{\pm}1.3$, $7.4{\pm}0.2$) regardless of whether the addition of insulin. Also, black groups were showed higher cell number of blastocyst ($33.2{\pm}2.5$, $35.5{\pm}2.6$ vs $31.2{\pm}2.1$, $31.3{\pm}2.2$). In conclusion, supplement of insulin producing black group in vitro maturation, it was effective in vitro maturation and embryonic development of pig embryos.

• Reproductive and Developmental Biology
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• v.31 no.1
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• pp.21-28
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• 2007

During early embryo development, Oct-4 is an important transcription factor for the early differentiation the present study was first examined methylation status in distal enhancer and promoter region of Oct-4 during mouse pre-implantation embryo development. In oocyte and sperm, high methylation was observed in both distal and proximal of promoter in Oct-4. Following fertilization relatively high methylation level remained until 8-cell stage embryos, but decreased at the morula and blastocyst stage. Specific gene knock down of Oct-4 by siRNA injection into zygote induced higher methylation rates of both distal and proximal region of promoter of Oct-4. These results suggest a functional link between the DNA methylation status of distal and promoter resign in the Oct-4 gene and the gene sequence-specific transcriptional silencing by exogenous siRNA injection during mouse preimplantation embryos.