• Asian-Australasian Journal of Animal Sciences
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• 제20권8호
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• pp.1190-1195
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• 2007

This study was conducted to improve efficiency of a follicle culture system without reducing developmental competence of intrafollicular oocytes. Preantral follicles (100 to $125{\mu}m$ in diameter) of F1 hybrid (B6CBAF1) mice were cultured singly for 216 h in modified ${\alpha}$-MEM-glutamax medium, to which 2.5 IU/ml hCG and epidermal growth factor was added 16 h prior to the end of culture. Medium change was either performed three times (54 h interval), twice (72 h interval), once (108 h interval), or not at all (216 h interval). Maturation (progression to the metaphase II stage) of intrafollicular oocytes was detected from 4 days after culture in the three-times change treatment, while all treatments yielded mature oocytes from day 5 of culture. Compared with the three-times change, decreasing the change frequency to once did not reduce the capacity to begin maturation (germinal vesicle breakdown of 82 to 86%), to mature (78 to 79%) and to develop into blastocysts after parthenogenetic activation (29 to 32%). Morphological parameters were similar among these treatments. Except for the no medium change treatment, similar colony-forming activity of inner cell mass cells after culturing of blastocysts in leukemia inhibitory factor-containing medium was detected, while the morphology of the colony-forming cells deteriorated in the change-once treatment compared with the change twice or three-times. In conclusion, the efficiency of the preantral follicle culture system could be improved by reducing frequency of medium change up to a 72 h interval (three times in total 216 h culture) without decreasing developmental competence of oocytes.

• 한국수정란이식학회지
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• 제27권1호
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• pp.57-62
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• 2012

Efficient oocyte activation is a key step for the success of nuclear transfer in cloning. Ionomycin sequentially combined with 6-DMAP is now widely used to activate normal oocytes for analytical studies of oocyte activation and to activate reconstructed oocytes after nuclear transfer. The present study investigated sources of oocytes, duration of ionomycin and 6-DMAP, laser and electric stimulation in goat oocyte activation in order to optimize the protocols. Goat ovaries were collected in individual abattoirs during the breeding season and were delivered to the laboratory within 6 h in saline with 100 IU/ml streptomycin and 0.05 mg/ml penicillin. The oocytes were denuded from the cumulus cell by pipetting with 0.2% hyaluronidase in PBS at 20~22 hr post maturation. Oocytes with the polar body were selected and assigned to four groups for parthenogenetic activation. To examine the effect of duration of ionomycin treatment, oocytes after 20~22 hr of maturation were treated with 2.5 uM ionomycin for 1 or 5 min times and then cultured in 2 mM 6-DMAP for 2 or 4 hr. The activated oocytes were cultured in mSOF at $38.5^{\circ}C$ in $CO_2$ 5%, $O_2$ 5% and $N_2$ 90% multi incubator. Cleavage and blastocyst development was observed at 48 hr and day 8 of culture $in$ $vitro$, respectively. Activation rates of oocytes exposed to ionomycin for 1 min(86.4%) were significantly higher than those treated for 5 min(74.3%) duration. This indicated that 1 min ionomycin treatment was most suitable for activation of goat oocytes. The duration of 6-DMAP treat duration was in 2 mM 6-DMAP for 2 hr after 1 min exposure to 2.5 uM ionomycin. The activation rate of oocytes incubated in 6-DMAP for 2 hour(82.5%) was significantly higher than those in oocytes treated with 4 hr(75.5%).

• 한국가축번식학회지
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• 제17권4호
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• pp.331-337
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• 1994

처녀발생은 난자의 세포질성숙을 투명대경화나 체외수정에 있어 난자 외적요소의 문제점을 배제하고 측정할 수 있는 지표이다. 본 실험에서는 체외성숙시간에 따른 소 난자의 처녀발생활성을 조사하였다. 도살장 난소로부터 회수한 미성숙난포란을 15% 소 태아혈청이 첨가된 TCM 199에서 6시간 간격으로 24~48시간까지 성숙시킨 후 7% ethanol로 7분간 활성화시켰다. 핵성숙과 세포질성숙은 rapid staining에 의해 핵형태와 전핵의 형성 유무로 판정하였다 핵성숙율은 24~48시간 사이 각각 81, 89, 72, 60 및 60%로 체외성숙 36시간에 성숙율이 최고였으나, 반면 감수분열 중기 II 염색체이상은 36시간부터 증가(0~30%)하였다. 에탄올처리에 의한 전핵형성율은 체외성숙 24~48시간에 각각 67, 68, 73, 84 및 87%였고, 그 중 이배체율은 각각 4, 5, 10, 16 및 20%로 성숙시간이 증가함에 따라 증가하였다. 위 실험의 결과 난자의 체외성숙 연장에 따라 전핵형성과 이배체수가 증가되는 것으로 나타났으며, 정상적인 핵성숙에 비해 세포질성숙은 더 많은 성숙시간이 필요한 것으로 나타났다. 이러한 결과들은 소 초기배 체외생산시와 핵치환용 핵수용란 생산시 적정 성숙시간 결정에 유용하게 이용될 수 있을 것이다.

• 한국가축번식학회지
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• 제19권3호
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• pp.191-195
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• 1995

본 연구는 체외성숙한 소의 난포란을 ethanol로 활성화시켰을 때 cytochalasin에 노출한 시간과 농도가 난포란의 배반포단계로의 발달에 미치는 영향을 검토하였다. 30시간 체외성숙시킨 소 난포란을 7% ethanol이 든 Dulbecco's phosphate buffered saline에 7분간 노출시켜 활성화를 시킨 후, cytochalasin D가 첨가된 TCM＋199＋10% fetal calf serum에서 일정시간 배양하여 세포주기를 억제시켰다. 난포란을 활성화시킨 후, 0, 5, 10 그리고 15시간 cytochalasin D(5$\mu\textrm{g}$/ml)에 노출시켰을 때, 5시간에서 가장 높은 배반포(16%), 팽윤배반포(13%), 부화배반포(7%)로의 발달률을 보였다. 또한 cytochalasin D 0, 2.5, 5 그리고 7.5$\mu\textrm{g}$/ml에서 7시간 노출시켰을 때, 2.5$\mu\textrm{g}$/ml에서 가장 높은 배반포(13%), 팽윤배반포(7%), 부화배반포(4%)로의 발달률을 보였다. 결론적으로 cytochalasin D는 난폰란의 단위발생에 중요한 역할을 하며, 성숙한 난포란은 cytochalasin D 2.5$\mu\textrm{g}$/ml에서 5시간 노출하였을 때 가장 높은 배반포로의 발달률을 보여주었다.

• Reproductive and Developmental Biology
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• 제33권1호
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• pp.7-11
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• 2009

This study was performed to confirm the microtubule assemblies and methylation patterns of porcine IVF and parthenogenetic embryos. Cumulus-oocyte complexes were collected and matured in vitro for 42 hr. Oocytes were fertilized by prepared fresh sperm or activated parthenogenetically by exposure to electric stimulation and 6-dimethylaminopurine. Porcine IVF and parthenogenetic embryos were cultured in vitro for 6 days. Embryos were stained by immunofluorescence staining method to observe the dynamic of nucleus and microtubules in the first mitotic phase and the methylation patterns in different developmental stages. After then, samples were confirmed and analyzed through a laser-scanning confocal microscope. IVF embryos had a centrosome originated from sperms, which was shown a $\gamma$-tubulin spot. However, $\gamma$-tubulin spot was not observed in parthenogenetic embryos. A lower methylation level was observed in IVF embryos compared to parthenogenetic ones at the morula and blastocyst stages. In conclusion, it is considered that microtubule assemblies and genetic regulation mechanism differ between parthenogenetic and IVF embryos.

• Reproductive and Developmental Biology
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• 제30권1호
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• pp.41-45
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• 2006

Electrical treatment has been widely used for porcine oocytes activation. However, developmental rates following electrical activation of porcine oocytes is relatively inefficient compared to other domestic animals. To investigate the effects of porcine oocytes on combined activation by both chemical and electrical treatment, in-vitro matured oocytes were activated by combined cycloheximide and electrical pulses treatment. Cumulus-free oocytes were exposed with NCSU-23 medium containing cycloheximide $(10{\mu}g/ml)$ for 0, 5, 10, 20, 30 min and then activated by electrical pulse treatment and cultured in PZM-3 for 8 days. Also effects of exposure to $6.25{\mu}M$ calcium ionophore for 2 min for cumulus-free oocytes were tested. The percentage of blastocyst formation in 10 min exposure to $10{\mu}g/ml$ cycloheximide and electrical pulse treatment was significantly increased (P<0.05) than in the control group. And exposure to $6.25{\mu}M$ calcium ionophore for 2 min with $10{\mu}g/ml$ cycloheximide for 10min and electrical pulse treatment significantly increased (P<0.05) the percentage of blastocyst developmental rates than the control group. In conclusion, activation by combined cycloheximide and electrical stimulation treatment promoted the subsequent development of porcine oocytes and improved the subsequence blastocyst development.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.617-620
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• 2004

The present study compares development of rabbit embryos generated using different oocyte activation protocols and reconstructed with embryonic or cumulus cells as nuclear donor. In vivo matured oocytes were collected from New Zealand White rabbits at 16 h after ovulation treatment and were activated at18 h of post-ovulation treatment. The following schemes of oocytes activation were tested: 1) single electric pulse (EP, 3.2 kV/cm, 3${\times}$20 $\mu$s, 0.3 M mannitol)+5 min culture in the presence of 5 mM Ionomycin, 2) single electric pulse (EP, 3.2 kV/cm, (${\times}$20 $\mu$s, 0.3 M mannitol)+1 h culture in the presence of 2 mM 6-DMAP, and 3) three electric pulses 30 min apart. Cleavage rate, percentage of expanded and hatched blastocysts as well as total cell number of blastomeres of parthenogenetic embryos were significantly higher using either EP+6-DMAP or 3${\times}$EP schemes, comparing with EP+Ionomycin. Development rate up to hatched blastocyst stage of cloned rabbit embryos using the EP+6-DMAP for activation of nuclei were 19% for embryonic cell nuclei and 36% for cumulus cell nuclei. The best activation protocol optimalized in this study was the combined treatment "P+6-DMAP" which may be potentially used for nuclear transfer protocol.

• 한국수정란이식학회지
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• 제23권2호
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• pp.93-100
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• 2008

This study was conducted to establish an in vitro maturation (IVM) system by selection of efficient macromolecule in the porcine in vitro production (IVP) technology. To choose the efficient macromolecules in the development of porcine embryos, the effects of 3 kinds of macromolecules (porcine serum; PS, porcine follicular fluid; pFF, and polyvinyl alcohol; PVA) supplemented in IVM media on the maturation, cleavage, and development rates to blastocyst of parthenogenetic activation (PA) and in vitro fertilization (IVF) embryos were examined. The maturation rates of porcine oocytes in media supplemented with PS were significantly higher than those with pFF and PVA (92.4% vs. 85.4%, 77.1%; p<0.05). In the cleavage and development to blastocyst rates, supplement with PS or pFF in the IVM media was more effective than PA. However, there were no significant differences in cleavage and development to blastocyst between PS and pFF group. From the results of this study, it was demonstrated that PS was optimal macromolecule in the porcine IVM media.

• 한국발생생물학회지:발생과생식
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• 제9권1호
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• pp.49-52
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• 2005

도축된 돼지의 난소에서 난포란을 채취하여 체외 성숙시킨 후 인위적으로 활성화시켜 이배체 배발달을 유기하기 위해 cytochalasin B를 2.5, 5.0, $7.5\;{\mu}g/mL$ 농도로 3, 5, 7 시간 처리한 후 NCSU23 배양액으로 7일간 배양하여 배발달율에 미치는 영향을 검사하였다. 체외 성숙된 돼지 난모세포를 활성화 처리하여 2일째 분할율을 관찰한 결과 각 처리의 분할율은 $39.0{\sim}48.9%$로 나타났으며, 처리별로 유의차가 없었다. 7일간 배양하여 상실배기 이상으로 발달한 난자들의 처리별 발달율 차이를 관찰한 결과는 cytochalasin B를 $5.0\;{\mu}g/mL$ 농도로 3시간 처리구(19.7%)에서 $2.5\;{\mu}g/mL$ 농도로 3, 5시간 처리한 구(9.4%)의 배발달율에 비해 유의적으로 높은 결과를 얻었다. 시간별과 농도별로 분석한 결과 $2.5\;{\mu}g/mL$ 처리구가 5.0, $7.5\;{\mu}g/mL$ 처리구들보다 유의적으로 낮은 배발달율을 보였다. 배반포기까지 발달한 난자들의 처리별 발달율 차이를 관찰한 결과는 cytochalasin B를 $5.0\;{\mu}g/mL$ 농도로 3시간과 5시간 처리구들의 배반포기 발달율은 9.4%와 9.0%로 $2.5\;{\mu}g/mL$ 농도로 3시간 처리구의 배발달율인 0%보다 유의적으로 높은 배발달율을 보였다. 시간별과 농도별로 분석한 결과 농도에 따라 $5.0\;{\mu}g/mL$ 처리구가 2.5와 $7.5\;{\mu}g/mL$ 처리구들보다 유의적으로 높은 배반포기 배발달율을 보였으며, 3, 5, 7시간 처리에 따른 유의적인 차이는 없었다. 이상의 결과로 돼지 난모세포를 65시간 체외 성숙 후 활성화 처리할 때 cytochalasin B $5.0\;{\mu}g/mL$로 $3{\sim}5$ 시간 처리하는 것이 가장 높은 배반포 발달율을 얻을 수 있었으며, 처리 농도가 배발달에 유의적인 영향을 미치는 것을 확인하였다.

• Reproductive and Developmental Biology
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• 제29권3호
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• pp.145-147
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• 2005

Autocrine or paracrine mediators released by the early embryo are implicated in the support of embryonic development. Their mechanisms and optimal embryo density in the medium, however, are uncertain. This study was conducted to establish the optimal embryo density and culture medium volume in mouse parthenogenetic embryo culture. In experiment 1, culture of parthenogenetirally activated oocytes at a concentration of $2{\~}4$ embryos/${\mu}L$ significantly improved development to the blastoryst stage ($72{\%}{\leq}$) compared with culture at the lower ($0.2{\~}1$e mbryos/${\mu}L,\;0\~37.5\%$) and the higher ($5{\~}6$ embryos/${\mu}L,\;30\~53\%$) concentration for 120 h when the oocytes were cultured in a 5 ${\mu}L$ drop under mineral oil In experiment 2, the embryos cultured at a concentration of $2{\~}4$ embryos/${\mu}L$ in a 10 ${\mu}L$ drop ($81.1{\%}$) showed significantly higher blastocyst rates than those in a 5 ${\mu}L$ drop ($68.5{\%}$). This study optimizes in vitro culture condition by modifying embryo density and the volume of culture medium It may give appropriate level of autocrine and/or paracrine factors to enhance viability and subsequent normal development of mouse parthenogenetic embryos in vitro.