• Korean Journal of Animal Reproduction
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• v.27 no.2
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• pp.103-113
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• 2003

This study was conducted to investigate the optimal condition for produce of large quantity recipient oocytes on porcine cloned embryos. In order to determined the optimum concentration and exposure time of ethanol, $Ca^{2+}$-ionophore, 6-DMAP and cycloheximide, in vitro matured oocytes were activated in TCM-199 containing various chemicals and 15% FBS. The activated oocytes were cultured in Whitten's medium containing 10% FBS at 5% $CO_2$. 1. When the porcine oocytes were activated with the ethanol, the best pronucleus formation, cleavage, and in vitro development rate were obtained in the 10% for 10 minutes, which was significantly higher than all of the other treatment(53.4%, 51.6% and 39.9%, respectively). 2. When the porcine oocytes were activated with the $Ca^{2+}$-ionophore, the pronucleus furmation, cleavage, and in vitro development rate were found significantly higher in the 25$\mu$M fur 2min. treatment than those of other concentration and exposure time(59.7%, 62.2% and 43.9%, respectively). 3. When the porcine oocytes were activated with the 6-DMAP, the best pronucleus formation, cleavage, and in vitro development rate were obtained in the 2mM for 2hr~4.5hr(57.3%, 58.4% and 29.0%, respectively). 4. When the porcine oocytes were activated with the cycloheximide, result showed that pronucleus formation, cleavage, and in vifro development rate were 52.1%, 47.7% and 31.8%, respectively, in the 5$\mu\textrm{g}$/ml for 4hr~6hr treatmrent, which was significantly higher than all of the other treatment. These results suggested that the active condition of porcine oocytes was established by optimum concentration and exposure time among different chemicals for produce of large quantity recipient oocytes.s.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.49-52
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• 2005

Flutter analysis procedure can be divided into two steps such as the computation of generalized mass, stiffness, and unsteady aerodynamic matrices and the calculation of major vibration modes frequency and damping values at each flight speed by solving the complex eigenvalue problem. In aircraft flutter analyses, most of the time is spent in the process of computing the unsteady aerodynamic matrices at each Mach-reduced frequency pairs defined. In this study, the method has been presented for computation and extraction of unsteady aerodynamic matrix portions dependent only on aerodynamic model using DMAP ALTER in MSC/NASTRAN SOL 145. In addition, efficient flutter analysis method has been suggested by computing and utilizing the unsteady generalized aerodynamic matrices for each analysis condition using the unsteady aerodynamic matrix portions extracted above.

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.425-435
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• 1998

To improve the efficiency of nuclear transplantation in bovine, in this study the development in vitro of nuclear transferred (NT) embryos was compared by different activation regimens of the enucleated oocytes. The effect of developmental stage and culture system of donor nuclei on fusion and development in vitro of NT embryos were also evaluated. Oocytes were collected from Hanwoo ovaries obtained from slaughterhouse and matured in Ham's F-10 supplemented with hormones. After 20~22 h maturation, the oocytes were vortexed to be free from cumulus cells and subsequently their nucleus and the first polar body were removed. Enucleated oocytes were divided into 3 groups for activation; the oocytes of group I were activated with ionomycin for 5 min and subsequently incubated in 6-dimetylarninopurine (DMAP) for 4 h, Those of group II were treated with DMAP for 4 h at 39 h after onset of in vitro maturation (IVM) and those of group III were kept in room temperature ($25^{\circ}C$) for 3 h at 39 h after onset of IVM. After in vitro fertilization (IVF) the embryos for muclear donor were cultured either by group culture (20 embryos /50 ${mu}ell$ drop) or individually (1 embryo /50 ${mu}ell$ drop) for 4 day and 5 day. At day 4 and 5 after IVF, blastomeres were separated in calcium-magnesium free medium, and then classified into small (day 5: $\leq$ 38 ${\mu}{\textrm}{m}$, day 4: $\leq$ 46 ${\mu}{\textrm}{m}$) and large (day 5 : $\geq$ 38 ${\mu}{\textrm}{m}$, day 4 ; $\geq$ 46 ${\mu}{\textrm}{m}$). The separated blastomeres were replaced into enucleated and activated recipient cytoplasm. The blastomere-oocyte complexes were fused by electrically. The NT embryos were cultured in TCM-199 containing 10% FCS in 39$^{\circ}C$, 5% $CO_2$ incubator for 7 day. The results obtained were summarized as follows; There were no differences in fusion and development to blastocyst between groups as group I (68%, 10%), group II (75%, 14%) and group III (73%, 9%), respectively. However, the cell number in blastocyst of NT embryos in group III were significantly fewer than in the other groups (P＜0.05). No differences in fusion and development to blastocyst were found between individual or group cultured and between small or large blastomeres of day 4 and day 5 donor embryos. From these results, it was concluded that the combination of ionomycin and DMAP, or treatment of DMAP at 39 h after onset of IVM were useful for the efficient of production of NT bovine embryos, and the individual cultured embryos could be simply used as donor nuclei for NT bovine embryo.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1361-1374
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• 2002

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.68-68
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• 2003

오늘날 형질전환동물의 생산과 같은 생명공학기술의 발달로 인하여 우리나라 재래산양은 그 모델동물로서 번식 생리학적으로 매우 중요한 가치를 지니고 있을 뿐만 아니라 고유의 유전자원 보존 측면에서도 산양복제와 같은 다양한 연구가 절실히 요구된다. 따라서 본 연구에서는 이러한 생명공학기술의 기초자료를 제공하고자 난포란의 활성화 방법과 단위발생란의 체외발달율을 조사하였다. 성숙한 미경산 재래산양을 공시동물로 하여 CIDR를 이용하여 발정동기화를 시켰으며, 과배란 처리는 FSH와 hCG를 이용하여 과배란 처리를 실시하였고 난포란의 회수는 외과적 방법으로 개복하여 난소의 난포로부터 난자와 난포액을 흡입하여 회수하였다 난포란의 활성화 처리는 전기자극법과 약물처리 방법을 사용하였으며, 전기자극방법은 DC 2.36㎸/cm, 17$\mu$sec 전압으로 1회 전기자극을 가하여 활성화를 유도하였으며, 약물처리법은 5$\mu\textrm{g}$/$m\ell$의 ionomycin 용액에서 5min, 1.9mM 6-DMAP용액에서 4시간동안 처리하여 활성화를 유도하였다. 단위발생란의 배양은 10% GS(goat serum)가 첨가된 M16 배양액과 10% FBS가 첨가된 TCM-199 배양액에서 난관상피세포와 6~7일동안 공배양을 실시하면서 체외발달율을 조사하였다. 활성화 방법에 따른 체외발달율은 전기자극 및 약물처리를 하였을때 분할율은 3.1% 및 67.9%였으며, 상실배 및 배반포로의 발달율은 0% 및 7.9%였다. 단위발생란의 체외 발달율은 10% GS가 첨가된 M16 배양액을 사용하였을 때 분할율은 68.0%였으며, 이중 12.0%가 상실배 또는 배반포로 발달하였다. 뿐만 아니라 10% FBS가 첨가된 TCM-199 배양액에 난관상피세포와 공배양을 실시하였을 경우는 72.0%가 분할하였으며, 이중 16.7%가 상실배 또는 배반포로 발달하였다. 이상의 결과로 볼 때 활성화 처리는 ionomycin과 6-DMAP 용액처리가 적합하며, 단위발생란의 체외배양은 보다 적합한 배양조건의 확립이 필요한 것으로 생각된다.

• Journal of Embryo Transfer
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• v.26 no.2
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• pp.123-128
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• 2011

In vitro maturation and activation of oocytes are primary steps towards biotechnological manipulation in embryology. The objectives of the present study were to determine the oocyte recovery rate per ovary, in vitro maturation rates of oocytes and rates of parthenogenetically activation of matured oocytes in Black Bengal goats. All visible follicles were aspirated to recover follicular fluid from individual ovaries (number of ovaries = 456). The immature cumulus oocyte complexes (COCs; n = 1289) were cultured in tissue culture medium (TCM)-199 supplemented with 10% (v/v) fetal bovine serum (FBS) for 27 hours at $39^{\circ}C$ with 5% $CO_2$ in humidified air. The matured oocytes (n = 248) were activated with 5 ${\mu}M$ ionomycin for 5 minutes followed by treatment with 2 mM 6-dimethylaminopurine (6-DMAP) for 4 hours. After activation, oocytes were cultured for another 14 hours in TCM-199 supplemented with bovine serum albumin (BSA) at $39^{\circ}C$ with 5% $CO_2$ in humidified air. The pronucleus formation in activated oocytes was determined by staining with 1% orcein (whole mount technique). Matured oocytes (n = 176) without activation stimuli were used as control. The mean number of oocytes recovered per ovary was $3.5{\pm}0.5$. The proportion of oocytes matured in vitro, confirmed by the presence of first polar body, was $42.1{\pm}4.7%$. Parthenogenetic activation, evidenced by formation of pronucleus, occurred in $37.2{\pm}15.8%$ of matured oocytes. No pronucleus formation was observed in control oocytes. In conclusion, a combination of ionomycin and 6-DMAP induces activation in one third of Black Bengal goats' oocytes.

• Journal of Embryo Transfer
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• v.13 no.3
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• pp.219-226
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• 1998

Enucleation of oocytes is an important limiting step for embryo cloning. We propose an enucleation technique based on the removal of chromatin after oocyte activation by aspirating the second polar body containing complemented chromatin. In a preliminary experiment to determine an optimal age of oocytes enucleation in rabbits, oocytes were enucleated at 15~20 hours post hCG. Recently ovulated oocytes were enucleated at a higher rate than aged oocytes. Microsurgical removal of the complemented chromatin in the second polar body was significantly more effective in enucleating than aspiration of a larger cytoplasm volume surrounding the first polar body of metaphase-arrested oocytes(96.8% versus 70.4%; P〈0.05). Moreover, compared with a nuclear transplantation protocol based on enucleation of metaphase-arrested oocytes and preactivated oocytes followed by treatment with 5 $\mu$M ionomycin for 5 min and 2 mM DMAP for 1 hr, there was no significant difference in the rate of blastocyst development. The ease with which modified technique can be performed is likely to render this technique widely useful for research and practice on mammalian cloning.

• Journal of Embryo Transfer
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• v.12 no.2
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• pp.133-139
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• 1997

Large scale production of cloned embryos requires the technology of multiple generational nuclear transfer(NT) by using NT embryos itself as the subsequent donor nuclei. In this work we investigated comparatively the effects of enucleated oocytes treated with ionomycin and 6-DMAP on the electrofusion rate and in vitro developmental potential in the first and second NT embryos. The embryos of 16-cell stage were collected from the mated does by flushing oviducts with Dulbecco's phosphate buffered saline(D-PBS) containing 10% fetal calf serum(FCS) at 47 hours after hCG injection. The recipient cytoplasms were obtained by removing the nucleus and the first polar body from the oocytes collected at 15 hours after hCG injection. The enucleated oocytes were pre-activated by 5 min incubation in 5$\mu$M ionomycin and 2 hours incubation in 2 mM 6-DMAP at 19~20 hours post-hCG before microinjection. In the first and second generation NT, the unsynchronized 16-cell stage embryos were used as nuclear donor. The separated donor blastomeres were injected into the enucleated activated recipient oocytes by micromanipulation and were electrofused by electrical stimulation of single pulse for 60 $\mu$sec at 1.25kV/cm in $Ca^2$+, $Mg^2$+ - free 0.28 M mannitol solution. In the non-preactivation group, the electrofusion and electrical stimulation was given 3 pulses for 60 $\mu$sec at 1.25 kV/cm in 100$\mu$M $Ca^2$+, $Mg^2$+ 0.28 M mannitol solution. The fused oocytes were co-cultured with a monolayer of rabbit oviductal epithelial cells in TCM-199 solution containing 10% FCS for 120 hours at 39$^{\circ}C$ in a 5% $CO_2$ incubator. The results obtained were summarized as follows: 1. In the first generational NT embryos, the electrofusion rate of preactivated and non-activated oocytes(80.4 and 87.8%) was not significantly different, but in the second generational NT embryos, the electrofusion rate was significantly(P<0.05) higher in the non-activated oocytes(85.7%) than in the preactivated oocytes(70.1%). 2) In the first and second generational NT embryos, the developmental potential to biastocyst stage was significantly(P<0.05) higher in the preactivated oocytes(39.3 and35.7%) than in the non-preactivated oocytes(16.0 and 13.3%). No significant difference in the developmental potential was shown between the first and second generational NT embryos derived from the preactivated oocytes. In conclusion, it may be efficient to use the oocytes preactivated with ionomycin and 6-DMAP for the multiple production of cloned embryos by recycling nuclear transfer.

• Reproductive and Developmental Biology
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• v.30 no.1
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• pp.1-5
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• 2006

Artificial activation of oocytes is a prerequisite for the successful cloning by nuclear transfer. This study investigated the effect of the different combination of activation agents such as electric pulse (E), thimerosal (Thi) + dithiothreitol (DTT), 6-dimethylaminopurine (6-DMAP) or cycloheximide (CH) on the developmental ability of porcine embryos derived from parthenogenetic activation (PA). PA embryos activated with chemicals showed significantly higher developmental rate to the blastocyst stage compared to the embryos activated with E alone ($21.5{\sim}28.1%$ vs. 18.0%, respectively). Of chemicals, Thi + DTT supported higher development to the blastoryst stage (28.1%). There was no significant difference in 1 pronucleus (PN) formation rate $(59.9{\sim}64.7%)$, but 2PN formation rate was significantly higher in PA embryos with additional activation using chemicals $(7.2{\sim}9.7%)$. In conclusion, this study shows that chemical activation after electric pulse can increase the development of porcine PA embryos.

• Reproductive and Developmental Biology
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• v.28 no.3
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• pp.181-185
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• 2004

This study was conducted to examine whether activation treatments, source of oocytes and culture conditions affect in vitro developmental ability of caprine oocytes. Mature Korean native goats were pretreated with intravaginal CIDR for 10 days. The goats were then treated with a single intramuscular injection of 1,000 IU PMSG on Day 8 or twice daily injection of a total of 70 mg FSH for 3 days from Day 8 of CIDR insertion for superovulation. All the goats were injected with 10 mg PGF/sub 2a/ on Day 8 and 400 IU hCG on Day 10 of CIDR. Oocytes were surgically collected by oviduct flushing(in vivo maturation) or direct follicle aspiration(in vitro maturation) through mid-ventral incision at 35 h after hCG injection. Fifteen to twenty oocytes were placed in TCM-199 medium containing 25 mM Hepes and hormones under mineral oil at 39℃ in a humudified atmosphere of 5% CO₂ in air for 22 to 24 h. After maturation, the oocytes were activated by electric stimulation or ionomycin + 6-DMAP. The activated oocytes were then cultured in M16, TCM-199 and mSOF media supplemented with proteins at 39℃ for 6 to 7 days. Activation treatments did not affect cleavage of the oocytes. The cleavage rates were 64.1% (41/64) in oocytes activated by electric stimulation and 76.5% (218/285) in oocytes activated by ionomycin + 6-DMAP. The proportion of development to blastocyst was 15.6% (34/218) in oocytes activated by ionomycin + 6-DMAP, but activation by electric stimulation did not support embryos developed beyond morula stage. There were no differences in the cleavage rates of activated oocytes experiencing in vivo (86.8%, 66/76) and in vitro maturation (69.0%, 127/184). However, the development rate to blastocyst stage was significantly (P<0.05) higher for oocytes matured in vivo (50.0%, 33/66) compared to in vitro (0.8%, 1/127). Culture conditions did not affect the cleavage of -activated oocytes. The cleavage rates were 51.6% (49/95) in M16, 64.3% (18/28) in TCM-199 and 81.0% (145/179) in mSOF, respectively. By contrast, the development rate of activated oocytes to stage was greater (P<0.05) for oocytes cultured in mSOF medium (23.4%, 34/145) than in M16 or TCM-199 (0.0%). Our results suggest that source of oocytes and culture conditions are major factors affecting in vitro development of caprine parthenogenetic oocytes.