• Reproductive and Developmental Biology
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• v.35 no.1
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• pp.105-113
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• 2011

The present study investigated the nuclear remodeling, development potential with telomerase activity and transcription level of X-linked genes (ANT3, HPRT, MeCP2, RPS4X, XIAP, XIST and ZFX) in the bovine somatic cell nuclear transfer (SCNT) embryos using two different fusion and activation methods. Female adult fibroblasts were injected into perivitelline space of in vitro matured oocytes. The oocyte-nucleus complexes were fused and followed by immediately either activated (Group 1), or activated at 1 h post-fusion (hpf) (Group 2), respectively. The incidence of normal premature chromosome condensation (PCC) at 1 hpf was slightly increased in the Group 2, compared to those of Group 1, but there was no significant (p<0.05) difference. The incidence of normal pronucleus (PN) and chromosome spread at 5 and 18 hpf were significantly (p<0.05) higher in the Group 2 than those of Group 1. The cleavage rate to 2-cell stage, developmental rate to blastocyst stage, and the mean number of total and ICM cell numbers were significantly (p<0.05) higher in the Group 2, compared to those of Group 1. Level of telomerase activity was significantly (p<0.05) higher in the SCNT blastocysts of Group 2, compared to those of Group 1. Transcript levels of HPRT, MeCP2 and XIST were not significantly (p<0.05) different between blastocysts of Group 1 and 2. However, transcript level of ANT3, RPS4X, XIAP and ZFX were significantly (p<0.05) up-regulated in the SCNT blastocysts of Group 2, compared to those of Group 1. Taken together, it is concluded that oocyte activation at 1 hpf induces the enhanced developmental potential by efficient nuclear remodeling and subsequent facilitation of the nuclear reprogramming of bovine SCNT embryos.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.145-156
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• 1988

This study was conducted to investigate the effect of embryo stage on bisection rates of embryos, on development of separated demi-embryos and on subsequent development to full term following transfer of demi-embryos to recipients. The results obtained in this study are summarized as follows. The 2-, 4-, 8-cell and morula embryos were mostly obtained at 36-42, 48-54, 62-66 and 72-78 hours after injection of hCG, respectively, and the average number of embryos recovered per head was 17.0. The bisection rate of 8-cell embryos was 83.6%, which was significantly higher than that of morula embryos, 65.5%. But the development of morula demi-embryos to blastocyst after in-vitro culture was better than that of 8-cell demi-embryos and the rate was 76.5% and 60.9%, respectively. When the 2, 10 and 15 cultured demi-embryos or intact embryos were transferred to each recipient mouse, respectively. the highest pregnancy rate was obtained when 15 embryos were transferred. And the overall offspring production rate of intact embryos was higher than that of demi-embryos.

• Journal of Embryo Transfer
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• v.23 no.1
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• pp.1-4
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• 2008

This study was performed to investigate the effect of laser-assisted hole in the zona pellucida (ZP) of frozen-thawed ICR mouse embryos on the process of hatching that is critical for expanded blastocysts to implant into endometrium, Vitrification medium, composed of ethylene glycol and sucrose supplemented with 7.5% (w/v) PVP, was used to freeze $2{\sim}4$ cell stage embryos recovered from oviducts of superovulated and mated female mice before storing them in $LN_2$. Right after thawing them, a laser beam was shot to make a hole in ZP followed by culturing in KSOM for $96{\sim}120\;hr$ and examining development to blastocyst and hatching every 12 hr. Laser-treated embryos showed significantly higher hatching rate compared to control (92.9% vs. 22.1%, p<0.05). From around Day 4, blastocysts developed from laser-treated embryos started hatching while the blastocysts of control group failed to hatch showing a lot of shrinkage. This study shows that a laser-assisted hole in ZP improves the hatching rate of blastocysts developed from frozen-thawed, in vitro cultured ICR mouse embryos.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.3
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• pp.293-301
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• 1996

In the present study, mouse follicular oocytes and 2-cell embryos(late -zygote stage embryos included) were cultured on the electric pad for electric stimulation in the culture incubator. In addition, follicular oocytes and embryos were tested for maturation and development under higher temperature condition($39^{\circ}C$).Mouse follicular oocyte maturation were not affected by anion electric stimulation and there is no significant difference in GBVD and MI between the control and experiment group after 4hr culture. In the embryo culture, it was found that more morula and blastocyst were found in the electric stimulation group rather than the control(96hr). This may seem to be caused with cytoplasmic $Ca^{2+}$ transient rise by electric stimulation(anion pad). On the other hand higher temperature incubation ($39^{\circ}C$) on the anion pad caused all the embryos degenerated within $12h{\sim}24hr$ culture. This was quite different from large animal embryos(bovine, pig, sheep), in which beneficial effect of high temperature incubation for oocyte maturation and embryo development were found.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.1
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• pp.13-20
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• 1997

The objective of this study was to determine the effect of EGF on the preimplantation development of mouse IVF embryos and their ICM and TE cell number. And also, we examined the expression of EGF-R protein on embryonic development by indirect immunofluorescence. The results obtained in these experiments were summarized as follows; Group culture (5 embryos/ 25 ${\mu}l$) showed more improved development rate to blastocyst than singly culture. This inferior development of singly cultured 2-cell embryos improved by the addition of EGF. Especially, 2-cell embryos cultured singly in 10 ng/ml of EGF (62.4%) indicated significant difference in development to blastocyst compared with control group (47.9%). Also, cell number of ICM and TE by differential labelling showed the increased pattern in the EGF treatment group. The stimulating effect of EGF with the development level was significantly increased after 4-cell stage (p<0.05). ICM proportion also showed the increased pattern with the developmental level in the EGF treatment group. In addition, expression of EGF-R by indirect immunofluorescence detected after 4-cell stage. Therefore, EGF could stimulate preimplantation mouse embryo development by binding with expressed EGE-R after 4-cell stage and produce the more increased ICM and TE cell number of blastocyst.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.126-133
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• 1998

Effects of B(a)P on preimplantation mouse embryos in vitro were studied. Preimplantation mouse embryos were exposed to a concentration of 0.3, 1, 3 and 10 $\mu$M B(a)P for 72 hrs. The toxicological effects of B(a)P were evaluated by morphological observation of embryos up to the blastocyst stage, and by measuring DNA, RNA and protein synthesis by radioactive precursor incorporation. At 1 $\mu$M B(a)P did not affect preimplantation development but interfered with hatching and ICM formation. Suppressing effect of ICM formation was dose dependent. At the eight cell stage, the developmental rate was decreased at above 3 $\mu$M of B(a)P. At the blastocyst stage, attachment and trophoblast outgrowth were diminished at the 10 $\mu$M of B(a)P and ICM formation was decreased at 1 $\mu$M of B(a)P. Inner cell number of blastocyst was decreased dose dependently. So, number of ICM was one of the most sensitive and toxicological end point. The RNA incorporation rate of 0.1 $\mu ^3$H-uridine was dosedependent and the protein incroporation of 0.5 $\mu Ci ^{35}$S-methionine showed a significant decrease after 48 hrs. But the DNA incorporation rate of methyl-$^3$H thymidine was not affected. Our results suggested that B(a)P did not affect the DNA replication but transcription was inhibited by dose dependent manner. There delay of development during the blastocyst stage was mainly due to the inhibition of RNA synthesis followed by protein synthesis.

• Journal of Embryo Transfer
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• v.15 no.2
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• pp.157-165
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• 2000

The efficiency of transgenic livestock production could be improved by early screening of transgene-integration and sexing of embryos at preimplantational stages before trasferring them into recipients. We examined the effciency of multiplex PCR analysis for the simultaneous confirmation of the trasgene and sex during the preimplantational development of bovine embryos and the possibility of green fluorescent protein(GFP) gene as a non-invasive marker for the early screening of transgenic embryos. The GFP gene was microinjected into the male pronuclei of bovine zygotes produced in vitro. The injected zygotes were co-cultured in TCM-199 containing 10% FCS with boving oviductal epithelial cells in a 5% CO2 incubator. Seventeen(13.0%) out of 136 gene-injected bovine zygotes developed by multiplex PCR analysis and the expression of GFP was detected by observing green fluorescence in embryos under a fluorescent microscope. Eight(67%) of 12 embryos at 2-cell to blastocyst stage were positive in the PCR analysis, but only two(11.8%) of 17 blastocysts expressed the GFP gene. Their sex was determined as 7 female and 5 male embryos by the PCR analysis. The results indicate that the screening of GFP gene and sex in bovine embryos by PCR analysis and fluorescence detection could be a promisible method for the preselection of transgenic embryos.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.271-278
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• 1994

The aim of this study was to compare the two culture systems 1) co-culture with cumulus cells and 2) chemically defined medium supplemented with amino acids (CR1aa) and fetal calf serum (FCS) of in vitro produced bovine embryos from follicular oocytes in vitro. Bovine follicular oocytes were collected from ovaries of slaughtered cows and matured in TCM199 supplemented with 10% FCS and hormones (1$\mu\textrm{g}$/ml FSH-P and 1$\mu\textrm{g}$/ml oestradiol-17$\beta$)24 hours at 39$^{\circ}C$ under 5% CO2 in air. The capacitation of spermatozoa from ejaculated or frozen bull semen was induced by centrifugation through Percoll density gradient (45%, 90%). Then capacitated spermatozoa (1$\times$106/ml) were inseminated into 50${mu}ell$ droplet containing matured follicular oocytes and incubated for 40~42 hours. Cleaved embryos of 2~4cell stage were transferred to the co-culture with cumulus cells and/or CR1aa medium supplemented with FCS. In semen source, the developmental rates to the blastocyst and the hatched blastocyst stages were higher in ejaculated semen(27.6% and 14.9%) than those of frozen-thawed semen(18.3% and 11.8%), respectively. In two culture systems, the proportions of embryonic development upto the blastocysts and the hatched blastocysts were higher of CR1aa medium (22.1% and 12.1%) than those of cumulus cell co-culture (16.8% and 5.1%), respectively. The number of cells in exapnded blastocysts was slightly higher in cumulus cells co-culture (122.6$\pm$8.5) than that in CR1aa medium (117.9$\pm$5.9). The present results indicated that the early development of in vitro produced bovine embryos can be maintained efficiently in CR1aa medium as well as in co-culture with cumulus cells.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.4
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• pp.347-356
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• 2020

Gangliosides are glycolipids in which oligosaccharide is combined with sialic acids. Our previous studies have suggested an interplay between ganglioside GD1a/GT1b and meiotic maturation capacity in porcine oocyte maturation. Furthermore, ganglioside GD1a and GT1b are known for its antioxidant activity, but it is still unclear whether possible antioxidant role of GD1a and GT1b is involved in porcine embryos development competence during in vitro culture (IVC). Here, the effects of ganglioside GD1a and GT1b on the embryonic developmental competence during in vitro culture of porcine were investigated. The effects of ganglioside GD1a and GT1b on the expression of ST3GAL2 were confirmed during embryos development (2-cell, 4-cell, 8-cell and blastocyst) using immunofluorescent staining (IF). As a result, the fluorescent expression of ST3GAl2 was higher in embryos at 4-8 cells stage than blastocysts. Blastocyst development rate significantly increased in only 0.1 μM GD1a and GT1b treated groups compared with control group. To investigate the cellular apoptosis, we analyzed TUNEL assay. In case of only 0.1 μM GD1a and GT1b treated groups, the total number of cells in blastocyst compared with control group, but there was no significant difference in the rate of apoptotic cells. We identified the intracellular ROS levels using DCF-DA staining. According to the result, ROS production significantly decreased in blastocysts derived from the 0.1 μM GD1a and GT1b treated groups. These results suggest that ganglioside GD1a and GT1b improve the developmental competence of porcine embryos via reduction of intracellular ROS during preimplantation stage.

• Reproductive and Developmental Biology
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• v.30 no.2
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• pp.119-124
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• 2006

The present study compared the developmental potential of cloned porcine embryos with mesenchymal stem cells (MSCs), fetal fibroblasts (FFs) and cumulus cells (CCs) by assessing the cleavage and blastocyst rate, total cell number, inner cell mass (ICM) ratio and apoptosis. MSCs were isolated by ficoll gradients from femur of -6 month old female pig, and maintained for primary cultures. FFs from a female fetus at ${\sim}30$ day of gestation were established, and CCs were obtained from cumulus oocyte complexes (COCs) aspirated from $3{\sim}6$ mm follicles in diameter. Donor cells at $3{\sim}4$ passage were employed for nuclear transfer (NT). COCs were matured and fertilized in vitro(IVF) as control. Cleavage rate was significantly (P<0.05) higher in IVF than in NT embryos with MSCs, FFs and CCs ($82.7{\pm}8.9%\;vs\;70.6{\pm}5.4,\;68.7{\pm}5.1\;and\;63.4{\pm}5.6%$, respectively). However, blastocyst rates in IVF and NT embryos derived from MSCs ($24.5{\pm}2.8\;and\;20.4{\pm}8.3%$) did not differ, but were significantly (P<0.05) higher than NT derived from FFs and CCs ($10.6{\pm}2.7\;and\;9.8{\pm}2.1%$). Total cell number and the ratio of ICM to total cells among blastocysts cloned from MSCs ($35.4{\pm}5.2\;and\;0.40{\pm}0.09%$, respectively) were significantly (P<0.05) higher than those from FFs and CCs ($24.9{\pm}6.2%\;vs\;0.19{\pm}0.16,\;23.6{\pm}5.5\;and\;0.17{\pm}0.16%$, respectively). Proportions of TUNEL positive cells in NT embryos from FFs and CCs ($6.9{\pm}1.5\;and\;7.4{\pm}1.7%$, respectively) were significantly (P<0.05) higher than in MSCs ($4.8{\pm}1.4%$) and IVF ($2.3{\pm}0.9%$). The results demonstrate that MSCs have a greater potential as donor cells than FFs and CCs in achieving enhanced production of cloned porcine embryos.