• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.68-68
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• 2001

Blastocyst formation, consisting of the inner cell mass (ICM) and trophectoderm (TE), is the first differentiation process during embryonic development in mammals. It has been hypothesized that the proportion of ICM to TE in the blastocyst may be crucial for subsequent developmental competence of early embryos, which it may be expressed as a sensitive indicator for evaluating in vitro systems. In this study ICM/total cell ratio of nuclear transfer (NT) embryos was compared with IVF-derived and in vivo embryos. Somatic cell nuclei obtained from a fetus at Day 40 of gestation were transferred into the enucleated oocyte and then cultured in NCSU 23 medium for 6 days as previously described (Koo et al., Biol. Reprod. 2000; 63:986-992). ICM and TE cells of blastocysts were determined by using a differential staining method (Han et al., Biol. Reprod. 1999; 60:1110-1113). Development rate (9.8$\pm$2.5%, 23/225) to the blastocyst stage of NT embryos was lower than IVF embryos (23.8$\pm$2.7%, 53/223). Thus, a difference was detected in the in vitro developmental rate to blastocyst stage between NT and IVF-derived embryos (P<0.05). In the next experiment, we investigated ICM and TE nuclei to assess the quality of blastocysts that produced by NT, IVF and in vivo, respectively. NT blastocysts (27.6$\pm$8.3) showed a smaller total cell number than IVF-derived (42.6$\pm$17.4) and in vivo embryos (283.9$\pm$103.5) (P<0.05). Ratios of ICM/total cells in NT, IVF and in vivo blastocysts were 15.1$\pm$ 18.6% (n=56), 12.3$\pm$9.2% (n=57) and 30.4$\pm$6.8% (n=40), respectively. Individual blastocysts for the ratio of ICM/total cells were assigned to 3 groups (I; <20%, II; 20 to 40% and III;>40%). As the results, most in vivo blastocysts (97.5%, 39/40) were distributed into group II while most NT (78.6%, 44/56) and IVF-derived blastocysts (82.5%, 47/57) were allocated to group I. Thus, our data show that NT or IVF-derived embryos have aberrant morphology during early development in vitro systems, suggesting that these anomalies may result in developmental failures of the NT embryos to term.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.5
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• pp.648-656
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• 2008

The objective of this study was to establish conditions for transfection of a foreign gene into somatic cells using cationic lipid reagents and to evaluate the effects of transfection on in vitro development of somatic cell nuclear transfer (SCNT) embryos. Green fluorescent protein (GFP) gene was used as a foreign gene and a non-transfected somatic cell was utilized as a control karyoplast. Monolayers of porcine cells were established and subsequently transfected with a GFP-expressing gene (pEGFP-N1) using three types of transfection reagents (LipofectAMINE PLUS, FuGENE 6 or ExGen500). Donor cells used for SCNT included transfected fetal or adult fibroblasts and oviduct epithelial cells, either serum-fed or serum-starved. Oocytes matured in vitro for 42 h were reconstructed with either transfected or non-transfected porcine somatic cells by electric fusion and activation using a single DC pulse of 1.8 kV/cm for $30{\mu}s$ in $Ca^{2+}$ and $Mg^{2+}-containing$ 0.26 M mannitol solution. Reconstructed oocytes were subsequently cultured in NCSU-23 medium for 168 h and the developmental competence and cell number in blastocyst were compared. There were no significant differences (P>0.05) in fusion, cleavage rates or development to the blastocyst stage between non-transfected, transfected, serum-fed and serum-starved cells. However, the rates of GFP-expressing blastocysts were higher in the FuGENE 6 group (71.4%) among transfection reagents and in the fetal fibroblasts group (70.4%) for donor cells. These results indicate that fetal fibroblasts transfected with FuGENE 6 can be used as donor cells for porcine SCNT and that GFP gene can be safely used as a marker of foreign genes in porcine transgenesis.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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• pp.25-32
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• 2010

The present study aimed to examine the effects of ${\gamma}$-linolenic acid (GLA) supplementation to in vitro culture (IVC) medium on in vitro developmental competence, freezability and morphology of in vitro matured and fertilized bovine embryos. In vitro produced (IVP) bovine zygotes were cultured in IVC medium supplemented with 0 (negative control), 15, 31, 62, 125, 250, 500 or 1,000 ppm GLA, 250 ppm linoleic acid albumin (LAA) and without any supplement as a control. Day 6 blastocysts derived from culture control were cultured in IVC medium containing either 62, 250 GLA or 250 LAA for 24 h, and at Day 7 were subjected to freezing or morphological examination by electron microscope. GLA 15 showed a tendency to have a higher cleavage rate at Day 2 (70.3%) than other groups. The hatching rate at Day 9 in LAA (38.2%) was significantly higher than the control and all treatment groups (p<0.05), while the blastocyst rate in LAA (32.4%) did not differ from those of 15 (30.5%), 31 (27.1%), and 62 GLA (33.1%) or the control (35.1%). GLA in concentrations of 125, 250, 500, and 1,000 ppm had significantly detrimental effect on the blastocyst rate compared to 15, 31 and 62 ppm GLA, LAA, and control groups (p<0.05). In contrast, the highest post-thaw survival rate (100%) was observed in the control group (p<0.01). Large lipid droplets were observed in the cytoplasm of trophoblastic cells, even in the control, but were abundant in GLA groups. Taking the results of the study into consideration, the addition of GLA to the culture medium for IVP bovine embryos at the dose of 15 ppm increased the developmental competence of zygotes and enhanced the cleavage rate up to Day 2. However, blastulation rate and post-thaw survival were not increased when GLA was added to the culture media.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.75-75
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• 2002

The present study was conducted for the production of transgenic cloned cows by somatic cell nuclear transfer (SCNT) that secrete human prourokinase into milk. To establish an efficient production system for bovine transgenic SCNT embryos, the offset was examined of various conditions of donor cells including cell type, size, and passage number on the developmental competence of transgenic SCNT embryos. An expression plasmid far human prourokinase (pbeta-ProU) was constructed by inserting a bovine beta-casein promoter, a green fluorescent protein (GFP) marker gene, and a human prourokinase target gene into a pcDNA3 plasmid. Three types of bovine somatic cells including two adult cells (cumulus cells and ear fibroblasts) and fetal fibroblasts were prepared and transfected using a lipid-meidated method. In Experiment 1, developmental competence and rates of GFP expression in bovine transgenic SCNT embryos reconstructed with cumulus cells were significantly higher than those from fetal and ear fibroblasts. In Experiment 2, the effect of cellular senescence in early (2 to 4) and late (8 to 12) passages was investigated. No significant differences in the development of transgenic SCNT embryos were observed. In Experient 3, different sizes of GFP-expressing transfected cumulus cells [large (>30 ${\mu}{\textrm}{m}$) or small cell (<30 ${\mu}{\textrm}{m}$)] were used for SCNT. A significant improvement in embryo development and GFP expression was observed when small cumulus cells were used for SCNT. Taken together, these results demonstrate that (1) adult somatic cells could serve as donor cells in transgenic SCNT embryo production and cumulus cells with small size at early passage were the optimal cell type, and (2) transgenic SCNT embryos derived from adult somatic cells have embryonic development potential.

• Journal of Embryo Transfer
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• v.31 no.1
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• pp.39-46
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• 2016

Cryopreservation has been applied successfully in many mammalian species. Nevertheless, pig embryos, because of their greater susceptibility to cryoinjuries, have shown a reduced developmental competence. The aim of this study was to evaluate the survival status of vitrified-warmed porcine embryos. Forced blastocoele collapse (FBC) and non-FBC blastocysts are vitrified and concomitantly cultured in culture media which were supplemented with/without fetal bovine serum (FBS). Porcine vitrified-warmed embryos were examined in four different methods: group A, non-FBC without FBS; group B, non-FBC with FBS; group C, FBC without FBS; group D, FBC with FBS. After culture, differences in survival rates of blastocysts derived from vitrified-warmed porcine embryos were found in group A~D (39.5 (A) vs 52.5 (B) and 54.8 (C) vs 66.7% (D), respectively, p<0.05). Reactive oxygen species (ROS) level of survived blastocysts was lower in group D than that of another groups (p<0.05). Moreover, total cell number of survived blastocysts was higher in group D than that of other groups (p<0.05). Otherwise, group D showed significantly lower number of apoptotic cells than other groups ($2.0{\pm}1.5$ vs $3.2{\pm}2.1$, $2.8{\pm}1.9$, and $2.7{\pm}1.6$, respectively, p<0.05). Taken together, these results showed that FBS/FBC improves the developmental competence of vitrified porcine embryos by modulating intracellular levels of ROS and the apoptotic index during the vitrification/warming procedure. Therefore, we suggest that FBS and FBC are effective treatment techniques during the vitrification/warming procedures of porcine blastocysts.

• Journal of Veterinary Science
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• v.23 no.2
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• pp.31.1-31.13
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• 2022

Background: Compared to medium containing 108 mM sodium chloride (NaCl), in vitro maturation (IVM) using a simple medium with reduced (61.6 mM) NaCl increases the cytoplasmic maturation and embryonic development of pig oocytes. Objectives: This study determines the effect of a complex medium containing reduced NaCl on the IVM and embryonic development of pig oocytes. Methods: Pig oocytes were matured in Minimum Essential Medium Eagle-alpha modification (αMEM) supplemented with 61.6 (61αMEM) or 108 (108αMEM) mM NaCl, and containing polyvinyl alcohol (PVA) (αMEMP) or pig follicular fluid (PFF) (αMEMF). Medium-199 (M199) served as the control for conventional IVM. Cumulus cell expansion, nuclear maturation, intra-oocyte glutathione (GSH) contents, size of perivitelline space (PVS), and embryonic development after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) were evaluated after IVM. Results: Regardless of PVA or PFF supplementation, oocytes matured in 61αMEM showed increased intra-oocyte GSH contents and width of PVS (p < 0.05), as well as increased blastocyst formation (p < 0.05) after PA and SCNT, as compared to oocytes matured in 108αMEMP and M199. Under conditions of PFF-enriched αMEM, SCNT oocytes matured in 61αMEMF showed higher blastocyst formation (p < 0.05), compared to maturation in 108αMEMF and M199, whereas PA cultured oocytes showed no significant difference. Conclusions: IVM in αMEM supplemented with reduced NaCl (61.6 mM) enhances the embryonic developmental competence subsequent to PA and SCNT, which attributes toward improved oocyte maturation.

• Development and Reproduction
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• v.4 no.1
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• pp.125-131
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• 2000

This study has used differential display-PCR, to amplify genes transcribed during the ovarian maturation induced by human chorionic gonadotropin (hCG). The cDNA expressed at the times of acquisition of oocyte maturational competence in red seabream (Pagrus major) following treatment with hCG was amplified and cloned. A full-length of cDNA for p. major was isolated using differential display-PCR and 5'RACE. This cDNA clone contained 2,662 nucleotides including the open reading frame that encoded 434 amino acids. Homology analyses, using the GenBank and EMBL general database searches, indicated that the nucleotides sequence of the cDNA does not have high homology with any other genes. This cDNA was judged to be a gene, which induction of maturational competence coincides with increase of mRNA related ovarian maturation. Consensus sequences which were consistent with protein kinase C phosphorylation sites and casein kinase II phosphorylation sites were identified. in vitro, the transcription level of mRNA related ovarian maturation increased between 9hr and 24hr following treatment of ovarian follicles with hCG. It was also increased after GtH-II (300 ng/ml) stimulation. Furthermore, in vivo, mRNA related ovarian maturation was rarely expressed prior to the acquisition of oocyte maturational competence, but was strongly expressed after the acquisition of oocyte maturational competence, suggesting that the hCG induction of maturational competence is brought about by the de novo synthesis of the mRNA related ovarian maturation in p. major.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.185-190
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• 2016

During the ovary preservation in low temperature, the cumulus oocyte complexes(COCs) lose their developmental competences after in vitro fertilization. We used phosphate-buffered saline (PBS) as a basic solutions of at various temperatures (25, 15 or $5^{\circ}C$) and supplemented them with 1mM glucose and 0.5mM glutamine as a source of carbohydrate metabolites. After recovery of COCs and in vitro fertilization, a significantly higher number of oocytes developed into blastocysts. The developmental competence of embryos that were originated from ovaries preserved at $15^{\circ}C$ was increased compared to those of 25 or $5^{\circ}C$. The maturation rate of oocytes was not differed between 24 and 36 h at $15^{\circ}C$ but showed lower than control group (71% versus 78%). In vitro-fertilized oocytes from ovaries stored at $25^{\circ}C$ for 24 h or at $5^{\circ}C$ for 24 h had a significantly decreased developmental potentials, but at $15^{\circ}C$ did not (27% versus 29% of blastocysts to develop into day 8). With these results, bovine ovaries can be preserved at $15^{\circ}C$ for 36 h without decreasing developmental capacity of in vitro-fertilized oocyte at least to the blastocyst stage. This information provides valuable information of preserving ovaries for embryo transfer or in vitro embryo production.

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.339-347
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• 2001

Sperm-mediated DNA transfer has a potential to markedly simplify techniques for the generation of transgenic animals. The exogenous DNA transfer by intracytoplasmic sperm injection (ICSI) procedure has been recently introduced in the production of transgenic animals. In this study, the developmental competence and tile expression rates of transgene were investigated after injection of spermatozoon or sperm head with enhanced green fluorescent protein (EGFP) gene into the mature porcine oocytes. The porcine oocytes were injected with intact sperm, membrane-disrupted sperm or sperm head. After injection. embryos were cultured in NCSU23 medium up to the blastocyst stage, and the developmental competence and expression rates were studied. The developmental rate (67.0%) of sperm injection group was higher than that (59.7%) of sperm head injection group, and the rates of EGFP expression were also significantly different between sperm injection and sperm head injection groups (42.1 vs 20.0%) (F＜0.05). In the porcine oocytes injected with sperm treated with different methods of membrane disruption, the removal of sperm membrane did not alter the developmental competence of embryos. The rate of blastocysts at 7 days after injection with intact and membrane disrupted sperm were 15.0 and 14.2%, respectively. The EGFP expression rates, 38.4% in embryos injected with frozen-thawed sperm was higher than that, 22.4% of embryos injected with the Triton X-100 treated sperm. Prior to injection, sperm were cultured in different EGFP gene concentrations from 0.Ol to 1ng/u${mu}ell$. However, no significant difference in developmental rates of embryos among different concentrations of EGFP gene were observed. The highest expression rate of EGFP gene, 37.4% was obtained from the embryos injected with spermatozoa treated with 0.1 ng/${mu}ell$ EGFP gene. These results suggested that exogenous DNA could be attached to the membrane disrupted sperm, and that these sperm could be used as a vector carrying foreign DNA into embryos.

• Journal of Embryo Transfer
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• v.15 no.1
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• pp.15-21
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• 2000

These studies were undertaken to evaluate morphological normality and development competence in vitro of hyman oocytes following vitrificatioin using ethylene glycol and electron microscopic grid. Human immature oocytes retrieved from natural and stimulated cycles was vitrified at 0 or 48 h and 0, 8 to 15 or 24 to 28 h after maturation culture, respectively. In oocytes retrieved from unstimulated cycle, no signifciant differences were found in morphological normality (56 to 63%) and fertilization (31 to 37%) rates between the times of vitrification. In stimulated patients, however, more oocytes were morphologically normal when vitrified at 24 to 28 h than when vitrified at 0 or 8 to 15 h after maturation culture. Regardlesss of the hormonal stimulation, high cleavage rates(83 to 100%) were obtained in all treatment groups but did not differ significantly. Twenty to 43% of cleaved oocytes developed to the blastocyst stage at 6 days after IVF. These results suggest that vitrified oocytes from unstimulated and stimulated cycles could develop to the blastocyst stage, regardless of the stages of vitrification.