• Korean Journal of Animal Reproduction
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• v.15 no.2
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• pp.103-107
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• 1991

This study was carried out to investigate the survival rate in vitro culture after frozen-thawed to used DMSO(dimethyl sulfoxide), glycerol and ethylene glycol of cryoprotective agents at the zona pellucida removed and encased into alien bisected embryo of the mouse early embryos. The results obtained from this study were as follows : 1. The survival rate of in vitro culture after frozen-thawed to used cryoprotective agents of three kinds at the zona pellucida removed bisected morula was 46.6%, 35.8% and 27.3%, total or mean were 36.6%, respectively. 2. The survival rate of in vitro culture after frozen-thawed to used cryoprotective agents of three kinds at the encased into alien bisected morula was 70.6%, 65.3% and 66.4%, total or mean were 67.4%, respectively. 3. The survival rate of in vitro culture after frozen-thawed to used cryoprotective agents of three kinds at the zona pellucida removed bisected blastocysts was 50.4%, 36.7% and 30.4%, total of mean were 39.2%, respectively. 4. The survival rate of in vitro culture after frozen-thawed to used cryoprotective agents of three kinds at the encased into alien bisected blastocysts was 71.1%, 66.7% and 63.9%, total or mean were 67.2%, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.650-654
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• 2003

The accuracy of Polymerase chain reaction (PCR) assay in sexing of sheep embryos was assessed in this study. A total of 174 ovine embryos produced in vitro at different stages of development (2, 4-8 cell stages, morula and blastocyst) were sexed. The universal primers (P1-5EZ and P2-3EZ) used in this assay amplified ZFY/ZFX-specific sequences and yielded a 445 bp fragment in both sexes. Restriction enzyme analysis of ZFY/ZFX-amplified fragments with Sac I exhibited polymorphism between sexes, three and two fragments in males and in females, respectively. For verification of accuracy, blood samples of known sex were utilized as positive controls in each test. The mean percentages of sex identification by this method at 2 cell, 4-8 cell, morula and blastocyst were $73.00{\pm}5.72$, $89.77{\pm}3.79$, $3.33{\pm}8.08$ and $79.6{\pm}9.09$, espectively with the over all male to female ratio of 1:0.87. It is concluded that the ZFY/ZFX based method is highly reliable for the sexing of sheep embryos.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.170-173
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• 2001

The objective of this study was to investigate the effect of selenium (Se) on in vitro development of bovine embryos. In CR1BSA, FBS-free medium, the bovine embryos could not proceed past the developmental block more efficiently to morula stage than in chemically undefined media. Addition of glutathione precursor, cysteine, with $\beta$-mercaptoethanol did not improve the development in chemically defined medium and neither did glutathione alone. Exogenous selenium improved the embryonic development to the morula and blastocyst stages at 6 days post-insemination (dpi) significantly (67.1% vs 57.5%, p<0.05), and blastocyst stage at 8 dpi (30.1% vs 20.5%, p>0.05). These improvements might be induced by elevated glutathione peroxidase activity due to addition of Se, and a possible mechanism of selenium to elevate the activity of glutathione peroxidase is discussed.

• Reproductive and Developmental Biology
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• v.40 no.2
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• pp.23-26
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• 2016

Transcription factor called activating enhancer binding protein 2C (AP2-gamma) is found in a variety of species and expressed from oocyte stage onwards, particularly restricted to the trophectoderm. Recent studies demonstrated that ablation of Tfap2c led to failure of tight junction biogenesis, particularly the knock-down embryos of Tfap2c did not form cavity from morula to blastocyst in mouse and pig. We speculated that the Tfa2pc may also be involved in desmosome biogenesis because blastocoel formation is coincident with the establishment of desmosome. To determine this, we depleted Tfap2c injecting siRNA into one-cell zygote and analysed the expression levels of genes that are required for desmosome complex such as PkP2, Pkp3, Dsc2, and Dsg2. We found only Pkp3 was up-regulated in the knockdowned morula embryos. Interestingly, upstream region of Pkp3 had putative Tfap2c binding sites. In conclusion, our results suggest that Tfap2c is not a crucial factor but somehow it might be involved in desmosome biogenesis directly or indirectly via Pkp3.

• Korean Journal of Animal Reproduction
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• v.8 no.1
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• pp.29-35
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• 1984

These experiments were carried out to obtain basic information necessary for in vitro culture of aggregated mouse embryos. Inbred ICR mice were used to obtain embryos. The zona pellucida was removed by placing the embryos in Whittingham's medium containing 0.5% protease for about 5-10minutes at 37$^{\circ}C$. Total 263 pairs of 2-, 4- and 8-cell zona free mouse embryos were subjected to aggregation by physical pressure and cultured in Whittingham's medium under the gas phase of 5% CO2 in air at 37$^{\circ}C$ for 24 to 60 hours. The results obtained in these experiments were summarized as follows: 1. Time needed for fusion of 2-, 4- and 8-cell embryos were 0-3, 0-3 and 0-3 hours, respectively and average time needed for in vitro development of 2-, 4- and 8-cell embryos after aggregation to morula and blastocyst were 42, 30 and 13.5 hours, and 51, 39 and 27 hours, respectively. 2. Of total 263 pairs of naked embryos, 227 were firmly aggregated together and the rats of aggregation in 2-, 4- and 8-cell embryos were 71.8, 88.3 and 97.0%, respectively. 3. The rates of aggregated pairs which obtained from 2-, 4- and 8-cell embryos developed to morula were 96.7, 95.6 and 96.9%, respectively, and embryos developed to blastocysts were 88.5, 89.7 and 90.8%, respectively. 4. Conspicuous differences in size of volume and inner cell masses between single and double blastocysts were observed. Although a single blastocolic cavity was formed in most double blastocysts, several formed two distinct cavities from the very beginning.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.287-294
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• 1994

This study was to investigate the effects of electrofusion, activation and developmental stage of donor embryos on in vitro development of nuclear transplant bovine embryos. A single blastomere nucleus from 8-cell to morula stage embryos produced by in vitro fertilization(IVF) was transferred into a recipient oocyte enucleated at 23∼25 h after in vitro maturation(IVM) or into a recipient oocyte enucleated and cultured for 14∼15 h. In one experiment the nuclear transplant embryos were subjected to additional activation treatments. Fusion rate of nuclear transplant eggs was high at direct current(D.C) voltages of 1.0 and 1.5 kV/cm 991.5 and 93.3%, respectively), but decreased at 2.0kV/cm (81.8%). Additional activation treatments by electric pulases or 7% ethanol did not affect the cleavage and development of nuclear transplant embryos. Development of nuclear transplant embryos slightly increased by delayed nuclear transfer and fusion (42∼43 h after IVM). With this system, blastocysts were obtained from transfer of 8-cell to morula stage donor nuclei (9.6%∼2.4%). The result of this study suggests that nucleo-cytoplasmic interactins, expecially activation of ooplast are very important for the development of nuclear transplant embryos, and donor cell stage does not affect the development of nuclear transplant embryos.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.365-373
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• 1994

To investigate the effect of EDTA on the in vitro development of parthenogenetic eggs of ICR strain mice, those were cultured in 35mm culture dishes containing NaHCO3-BMOC-3 medium supplemented with 10, 50, 100, or 500$\mu$M of EDTA at 37$^{\circ}C$ for 96hrs. under the atmosphere of 5% CO2 and 95% air. EDTA supplementation of 10, 50, or 100$\mu$M to medium significantly(P<0.01) increase morula and blastocyst formation rate compared with controls in haploid(19.8, 25.9, 39.0% vs. 0.0%). And compared with 10, or 50$\mu$M of EDTA supplementation, significantly(P<0.01) higher morula and blastocyst formation rate resulted from EDTA supplementatin of 100$\mu$M. Both the nuclear number and diameter of blastocysts developed from parthenogenetic eggs were not affected by the morphological types when they were cultured, or the supplementary concentrations of EDTA. The nuclear number of blastocysts developed from haploid, diploid, and immediately cleavaged eggs was 44.8$\pm$1.2, 45.2$\pm$1.5, and 45.4$\pm$1.8, respectively. And the diameter of those eggs ranged 104.4$\pm$1.8, 104.3$\pm$1.2, and 103.8 1.3$\mu$m, respectively.

• Korean Journal of Animal Reproduction
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• v.17 no.3
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• pp.243-248
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• 1993

Bovine embryos at 2-to 8-cell produced by in vitro matured/in vitro fertilized(IVM/IVF) were cultured in TCM 199 or Synthetic oviduct fluid(SOF) with 10% fetal bovine serum(FBS) or cocultured with cumulus or bovine oviduct epithelial cell(BOEC) in TCM-199 or SOF medium. In experiment 1, the proportions of embryos developed to morula and blastocysts stages in TCM 199 medium were higher when they were co-cultured with cumulus cell(29%) or BOEC(33%) than that of TCM 199 with 10% FBS(12%, P<0.01). In experiment 2, embryos deived from IVM/IVF were cultured in SOF with 10% FBS or cocultured with cumulus cell or BOEC in same medium. The higher development rates of IVM/IVF embryos developed beyond morula stages were obtained in cumulus cell co-culture group(39%) than those of BOEC group(26%) and SOF with 10% FBS group(17%, P<0.01). The present results indicated that the early development of IVM/IVF embryos can be maintained efficienty in SOF with cumulus cell co-culture.

• Korean Journal of Animal Reproduction
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• v.13 no.3
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• pp.164-170
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• 1989

These experiments were carried out to develop the practical technique for the production of identical twins in cattle. Morula and blastocyst stage embryos collected from superovulated donors were bisected into halves by micromanipulation. The resulting demi-embryos were transferred to the uterine horn ipsilateral to the corpus luteum of synchronous recipients. The viability of demi-embryos after splitting was also evaluated by culturing demi-embryos with and without a zona-pellucida. The results obtained in these experiments were summarized as follows : 1. Of total 132 embryos collected by superovulation from 29 donors, 37 embryos were morular and 30 at blastocyst stages. 2. Total 111 demi-embryos were produced from 67 embryos by bisection and 98% of those were normal in morphology. 3. The viability of the demi-embryos cultured with zona-pellucida ranged from 70 to 76.5% and that of the demi-embryos without from 53.8 to 69.2%. 4. The viability of demi-embryos obtained from morula was 63.6% and that of demi-embryos from blastocyst was 73.3%, respectively. 5. 35 demi-embryos were transferred to 21 recipients, 7 of which were confirmed to be pregnant by rectal palpation at 55∼60 days after embryo transfer. One of them produced a calf and 6 are still on pregnancy.

• Reproductive and Developmental Biology
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• v.29 no.4
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• pp.229-234
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• 2005

Methods for activation of reconstructed oocytes were examined for the production of nuclear transfer (NT) rat embryos using fetal neural stem cells as donor. Neural stem cells were isolated from Day 14.5 rat fetuses, and the oocytes for recipient cytoplasm were recovered from 4-week old Sprague Dawley rats. After enucleation and nuclear injection, the reconstructed oocytes were immediately exposed to activation medium consisting of 10 mM $SrCl_2$ for 4 h (immediate activation after injection; IAI), or cultured in vitro for $2\~3$ h before activation treatment (injection before activation; IBA). Pre-activated oocytes were also used for NT to test reprogramming potential of artificially activated oocytes. The oocytes were grouped as IIA (immediate injection after activation) and ABI (activation $2\~3$ h before injection). Following NT, the oocytes were cultured in vitro. Development of the NT embryos was monitored at 44 and 119 h after activation. The embryos in groups IAI, mA, and IIA were cleaved to the 2-cell stage at the rates of $36.6\%\;(15/41),\;39.5\%\;(17/43)\;and\;46.3\%$ (25/54), respectively. However, in the ABI group, only one embryo ($1.8\%$, 1/55) was cleaved after activation. After in vitro culture, two NT embryos from IAI group had developed to the morula stage $(4.9\%\cdot2/41)$. However, no morula or blastocyst was obtained in the other groups. These results suggest that immediate activation after injection (IAI) method may be used for the production of rat somatic cell NT embryos.