• Clinical and Experimental Reproductive Medicine
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• v.41 no.2
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• pp.47-61
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• 2014

Stored maternal factors in oocytes regulate oocyte differentiation into embryos during early embryonic development. Before zygotic gene activation (ZGA), these early embryos are mainly dependent on maternal factors for survival, such as macromolecules and subcellular organelles in oocytes. The genes encoding these essential maternal products are referred to as maternal effect genes (MEGs). MEGs accumulate maternal factors during oogenesis and enable ZGA, progression of early embryo development, and the initial establishment of embryonic cell lineages. Disruption of MEGs results in defective embryogenesis. Despite their important functions, only a few mammalian MEGs have been identified. In this review we summarize the roles of known MEGs in mouse fertility, with a particular emphasis on oocytes and early embryonic development. An increased knowledge of the working mechanism of MEGs could ultimately provide a means to regulate oocyte maturation and subsequent early embryonic development.

• Reproductive and Developmental Biology
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• v.41 no.2
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• pp.33-40
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• 2017

X-chromosome inactivation is one of the most complex events observed in early embryo developments. The epigenetic changes occurred in female X-chromosome is essential to compensate dosages of X-linked genes between males and females. Because of the relevance of the epigenetic process to the normal embryo developments and stem cell studies, X-chromosome inactivation has been focused intensively for last 10 years. Initiation and regulation of the process is managed by diverse factors. Especially, proteins and non-coding RNAs encoded in X-chromosome inactivation center, and a couple of transcription factors have been reported to regulate the event. In this review, we introduce the reported factors, and how they regulate epigenetic inactivation of X-chromosomes.

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.111-116
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• 1994

This study was carried out to investigate the aggregation rate of isolated mouse 2-, 4- and 8-cell stage blastomeres in phytohemagglutinin(PHA) solution. The morphologically normal embryos were collected from the oviduct of superovulated female mouse by flushing with M2 and the zona pellucida of embryos were removed with 0.5% pronase. The blastomeres were isolated by pipetting after plunging into Ca++-Mg++free PBS for 20 min. The result showed that aggregation rate in 0.5% (84.9~93.1%) was higher than that in 1.0% PHA(76.0~82.1%). Optimal aggregation time was 60min (83.9~100.0%) when compared with 30min (78.8~87.5%). Developmental to blastocyst in recombinated blastomeres was higher under conditions of 0.5% PHA solution and 60-min aggregation than that under other conditions.

• Korean Journal of Animal Reproduction
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• v.14 no.2
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• pp.101-106
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• 1990

These mxperiments were carried out to investigate the effect of rabbit anti-bovine cumulus cell antibodies on in vitro fertilization and following development of bovine follicular oocytes matured in vitro. The bovine ovaries were obtained at a slaughter house and the follicular oocytes surrounded by cumulus cells were collected by puncturing follicles with 2~6mm of diameter. Bovine oocytes were matured in vitro for 24~26hrs in a CO2 incubator with 5% CO2 in air at 39$^{\circ}C$ and subsequently cultured in medium containing cumulus cell antibody for 1 hour. The medium used for maturation was TCM-199 supplemented with hormones, pyruvate, FCS and antibiotics. Epididymal spermatozoa were capacitated by in vitro culture for 2~3 hrs in BO solution 10~15 matured oocytes into the suspension of capacitated spermatozoa. Six hour after insemination the eggs were transferred to TCM-199 supplemented with FCS(10%) and then cultured for 7 days. The results obtained in these experiments were summarized as follows : 1. When the follicular oocytes matured in vitro were treated with antibody to intact cumulus cells, the fertilization rate of cumulus intact and removed oocytes was ranged to 45.0 to 53.7%. These value is slightly lower than that(64.3%) of follicular oocytes not treated with the antibody, and increased frequency of both male and female pronuclear formation was found in cumulus intact oocytes cultred in medium without the antibody(p<0.05). 2. The fertilization rate of cumulus intact and removed oocytes treated with antibody to solubilized cumulus cells was ranged 45.0 to 52.5%, significantly lowre than that(62.8%) of oocytes cultured in antibody free medium, and increased frequency of ova with male and female pronuclei was found when cumulus cells were present(p<0.05). 3. The rates of cumulus cell intact and removed oocytes developed to 8-, 16-cell and morula or blastocyst after treatment of intact and solubilized cumulus cell antibody were ranged 7.1 to 14.5, 2.9 to 5.9 and 1.5 to 2.9%, respectively, slightly lower than 18.6, 10.0 and 8.6% of cumulus intact oocytes cultured in medium without the antibody. The results of this stduy indicate that cumulus cells promote not only normal fertilization with proper pronuclear formation, but embryo development and that the beneficial effect of cumulus cell to the pronuclear formation and embryo development is blocked by the action of antibody to cumulus cell.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.2
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• pp.109-113
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• 1998

Objective: To ananlyze the direct effect of nitric oxide (NO), generated from sodium prusside (SNP) on the embryo developments in reproductive process. Design: Ova from mouse were treated to allow fertilization in in vitro culture. And the samples of fertilized ova were alloted into five alliqutos. Each alliquot was cultured in media treated with either concentration at 0 (n=92), $25{\mu}M$ (n=84), $50{\mu}M$ (n=80), $100{\mu}M$ (n=77), $500{\mu}M$ (n=54) of SNP. Main Outcome Measure: Rates of embryonal cell cleavages, viability and cell morphology were assessed during in vitro fertilization and culture. Results: As analyse the cell cleavage at 24 hours after in vitro culture of fertilised egg in variuos NO concentration, all of egg cells of each alliquot were developed to $2\sim4$ cell stage. But the alliquot of egg cells treated with $50{\mu}M$, which were totally degenerated. And also all embryonal cells of each alliquot were developed to 8 cell stage and morula stage on culture continuosly. And the embryonal cells of each alliquot were analysed at 24 and 48 hours following the in vitro culture. The rates of cell fragmentation and fusion were $4.2{\pm}3.4%$ in control group which is not treated with NO, while experimental groups was high, as rated $23.4{\pm}6.2%$ in $25{\mu}M$, $28.2{\pm}5.7%$ in $50{\mu}M$ and $32.1{\pm}6.4%$ in $100{\mu}M$ concentration of NO. Accordingly the rate of abnormal morphology of embryonal cell in control was lower significantly than that in each alliquot of experimental groups (p<0.05). And the degenerated rates of embryonal cells were 0% in control, $17.8{\pm}6.7%$ in $25{\mu}M$, $23.6{\pm}4.7%$ in $50{\mu}M$ and $26.8{\pm}11.2%$ in $100{\mu}M$ at 8 cells and morula on culture of 48 and 72 hours. On the examination of embryonal cells developed to blastocyst through in vitro culture, the rates of degenerated cells were $16.8{\pm}7.2%$ in control, $37.5{\pm}6.2%$ in $25{\mu}M$, $73.4{\pm}4.6%$ in $50{\mu}M$, 100% in $100{\mu}M$. Conclusion: This results suggeted that the NO in any concentrations is harmful on embryos in view of morphology as well as viability of cell, and the toxicity of NO on embryo is stronger at condition in higher concentration of NO.

• Journal of Embryo Transfer
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• v.25 no.3
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• pp.145-148
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• 2010

Oxygen consumption has been regarded as a useful indicator for assessment of mammalian embryo quality. This study was performed to investigate whether oxygen consumption reflects morphological grade of in vivo derived bovine blastocyst-stage embryos (blastocyst). The oxygen consumption of in vitro produced blastocyst was compared to its total cell number. In addition, pregnant rate was measured after transplantation of in vivo blastocysts with different oxygen consumption. The quality of blastocyst collected on day 7 after artificial insemination was categorized as grade I and II (G I and G II) based on microscopic observation of the morphology. Oxygen consumption of blastocyst was measured using a scanning electrochemical microscopy (SECM) and total cell number of in vitro blastocyst was enumerated by counting cells stained by propidium iodide. Pregnancy of recipient cow was confirmed with rectal palpation after 60 days of embryo transfer. The oxygen consumptions of G I blastocysts were significantly higher than those of G II blastocysts ($10.2{\times}10^{15}/mol\;s^{-1}$ versus $6.4{\times}10^{15}/mol\;s^{-1}$, p<0.05). Total cell numbers of in vitro blastocysts were 74.8, 90.7, and 110.2 in the oxygen consumption of below 10.0, 10.0~12.0, and over $12.0{\sim}10^{15}/mol\;s^{-1}$ respectively. Total cell number was significantly increased in embryos with high oxygen consumption (p<0.05). Pregnant rate in recipient cow was 0, 50, and 85.7% in the transplantation of embryo with the oxygen consumption of below 10.0, 10.0~12.0, and over $12.0{\times}10^{15}/mol\;s^{-1}$, respectively. These results suggest that measurement of oxygen consumption may help increase the pregnant rate of bovine embryos.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.161-170
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• 2015

These studies were conducted to establish the practical Hanwoo (Korean native cattle) improvement system through the combining of embryo transfer technology and confirming individual Hanwoo oocyte culture system and to investigate that correlation of Hanwoo carcass classification (intramuscular marbling) and oocyte donor for blastocyst production in vitro. In case of Hanwoo, the carcass meat quality grades were divided to grade $1^{{+}{+}}$, $1^{+}$, 1, 2, and 3 depends on fat distribution of longest muscle cross-sectional surface. As results, the numbers of follicular oocytes collected from individual fundamentally-registered Hanwoo yielded $1^{{+}{+}}$, $1^{+}$, 1, 2 and 3 meat quality were 9.5, 9.4, 8.5, 8.8 and 8.8 per ovary, respectively. The numbers of retrieval oocyte from follicles were significantly higher in the cattle yield $1^{{+}{+}}$, $1^{+}$ meat quality than in the cattle yield 1, 2 and 3 meat quality (p<0.05). The rates of blastocyst formation were 18.2, 21.3, 29.4, 30.9, and 31.5% in the cattle yield $1^{{+}{+}}$, $1^{+}$, 1, 2 and 3 meat quality of after in vitro maturation, respectively. It was significantly lower in the cattle yield $^{{+}{+}}$ and $1^{+}$ meat quality than in the cattle yield 1, 2 and 3 meat quality (p<0.05). In order to evaluate embryos quality, TUNNEL assay was conducted for each meat quality grade using blastocyst stage embryo on day 8. The results showed that apoptosis cell number was higher tendency in the cattle yield $1^{{+}{+}}$and $1^{+}$ meat quality (81 and 79, respectively) than in the cattle yield 1, 2 and 3 meat quality (51, 48 and 50, respectively) but there was no statistical significance in each group. After embryo transfer, the conception rate of recipient was 53.5 (23 out of 43), 52.1 (38 out of 73) and 58.0% (58 out of 100) in the meat quality of 1, $1^{+}$ and $1^{{+}{+}}$, respectively. These results showed that the conception rate was significantly higher in the cattle yield 1 meat quality than in the cattle yield $1^{{+}{+}}$, $1^{+}$, 2, and 3 meat quality (p<0.05). In summary, these results indicate that the application of confirming Hanwoo individual oocyte culture system and embryo transfer technology can make good use of the genetic resources conservation and improvement of Hanwoo. Relevance of the meat quality grade and reproductive ability of carcasses of Hanwoo will be considered to be one of the effective means for the associated research with obesity and reproduction.

• Journal of fish pathology
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• v.5 no.1
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• pp.1-7
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• 1992

CHSE(Chinook Salmon Embryo)-214 fish cell lines was cultured in Eagle's minimal medium (MEM) supplemented with 10% fetal bovine serum and 2mM-glutamin. Optimum growth temperature of CHSE-214 cell line was $20^{\circ}C$. Infectious pancreatic necrosis virus(IPNV) was successfuly multiplied and showed the cytopathic effect in CHSE-214 cell line. Infection symptom of IPNV was observed with inverted phase contrast microscopy. At 6h-12hrs post-infection, the cells infected with IPNV were similer to normal cells. At 18-24hrs post-infection, the cells were somewhat round form and a little swollen form than normal cells. At 30hs post-infection, the cells were becoming more abnormal cells. At 48-68 post-infection, the infected cells were lysed and showed the severe cytopathic effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3843-3849
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• 2013

This study was conducted to determine the effects of fetal bovine serum (FBS), bovine serum albumin (BSA) and epidermal growth factor (EGF) on blastocoel formation, total cell number, apoptosis and apoptosis-related gene expression of porcine diploid parthenotes developing in vitro. The addition of 0.4% BSA to the culture medium enhanced the development of 2-cell stage parthenotes to the blastocysts stage (p<0.01). Treatment of FBS reduced cell numbers of blastocysts (p<0.01) and increased the percentage of apoptosis in blastocysts (p<0.001). However, BSA increased cell numbers, only in the presence of EGF reverse-transcriptase polymerase chain reaction revealed that EGF enhanced the mRNA expression of Bcl-xL in the presence of 0.4% BSA but BSA and EGF alone had no effect. However, Treatment of FBS reduced Bcl-xL mRNA expression (p<0.05) and enhanced Bak expression. This result suggests that apoptosis related gene expression is significantly affected by supplements, which may result in alteration of apoptosis and embryo viability of porcine embryos developing in vitro.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.70-70
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• 2002

형질전환 가축을 생산하기 위하여 최근 체세포 복제 기법을 이용하고 있다. 이러한 체세포를 이용한 형질전환 동물의 생산에는 체세포내에 유전자의 도입 효율이 직접적인 영향을 주게 된다. 따라서 본 연구는 세포내 유전자의 transfection 효율을 높이고자 한우의 체세포를 이용하여 여러 가지 조건에서 유전자 도입을 실시하였다. 세포내 유전자 도입 방법은 electroporation (EP) 방법을 이용하였다. 사용한 세포는 소의 귀세포(KbESF), 태아섬유아세포 (KbFF), 그리고 대조구로서 CHO cell을 이용하여 GFP 유전자를 도입하였다. EP는 0.4 cm cuvette을 사용하였고, voltage는 0.25 kV, 그리고 field strength 는 0.625 kV/cm 조건으로 실시하였으며, pulse times은 각각 1, 2, 또는 3회를 사용하였다. KbFF와 KbESF에서는 각각 pulse times을 증가시킬수록 유전자도입 세포수가 증가하였으나 (KbFF: 81, 634, 1,065 cells/$10^{6}$ cells, KbESF: 1,011, 5,567, 15,408 cells/$10^{6}$ cells), CHO cell에서는 pulse times을 증가시킬 수록 오히려 유전자도입 세포수가 감소하였다 (CHO: 1,591, 687, 297 cells/$10^{6}$ cells). 그리고 2주 동안 neo selection을 실시 한 결과 KbFF, KbESF, CHO에서 각각 93, 35, 184 colony가 선발되었으며, 이 중 65.6%, 8.6%, 4.3% 가 GFP 형광 발현 colony로 나타났다. 한편 CHO cell에서 transfection cell수가 감소된 것은 EP의 자극으로 인해 손상된 세포가 많이 발생한 것으로 나타났다. 또한 neo selection에서 선발된 colony중 GFP가 발현되지 않거나 일부만 발현되는 colony들이 많이 발생하였는데, 이것은 세포내 유전자가 transfection되지 않은 세포도 neo selection에서 선발된다는 것을 제시하고 있다. 따라서 체세포를 이용한 형질전환동물 생산을 위해서는 세포내 유전자 도입과 선발 과정에서 나타난 colony에 대하여 보다 엄격한 screen을 하는 것이 필요한 것으로 생각된다.