• The Korean Journal of Zoology
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• v.29 no.2
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• pp.79-85
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• 1986

The purpose of the present experiment is to make certain the exsistence of cAMP phosphodiesterase (PDE) in mouse oocytes and confirm its possible role on meiotic resumption. The results showed two types of cAMP in the oocytes with different Michaelis constants (Km) with specific maximum (Vmax); The Km and Vmax of one of two types of PDE were estimated at $0.14 \\pm 0.01 \\muM$ and $0.42 \\pm 0.07$ fmol cAMP hydrolyzed/oocyte/minute, and the other at $14.5 \\pm 2.0 \\muM$ and $2.2 \\pm 0.5$ fmol cAMP hydrolyzed/oocyte/minute. cAMP hydrolysis by PDE was reversibly inhibited in vitro by presence of theophylline or isobutyl-methyl-xanthine (IBMX), which is well known as an inhibitor of oocyte maturation. Consequently, it can be assumed that maturation of oocyte is affected by the high level of intracellular cAMP, and its level is well maintained by presence of PDE inhibitor, such as theophylline and IBMX.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.2
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• pp.123-129
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• 2019

Many transcription factors are involved in directing the growth of porcine oocytes. The localization and expression level of a given transcription factor often differ at each stage of early embryonic growth, which spans from fertilization to the formation of the blastocyst. A hallmark of the blastocyst stage is the separation of the endodermal and mesodermal ectoderm. The embryo's medium and its effects are known to be crucial during early development compared to the other developmental stages, and thus require a lot of caution. Therefore, in many experiments, early development is divided into the quality of oocyte and cumulus cells and used in experiments. We thought that we were also heavily influenced by genetic reasons. Here, we examined the expression patterns of five key transcription factors (CDX2, OCT4, SOX2, NANOG, and E-CADHERIN) during porcine oocyte development whose expression patterns are controversial in the pig to the literature. Antibodies against these transcription factors were used to determine the expression and localization of them during the early development of pig embryos. These results indicate that the expressions of key transcription factors are generally similar in mouse and pig early developing embryos, but NANOG and SOX2 expression appears to show speciesspecific differences between pig and mouse developing embryos. This work helps us better understand how the expression patterns of transcription factors translate into developmental effects and processes, and how the expression and localization of different transcription factors can crucially impact oocyte growth and downstream developmental processes.

• Korean Journal of Animal Reproduction
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• v.13 no.3
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• pp.188-194
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• 1989

These experiments were carried out to investigate fertilizable and developmental ability after zona drilling the unfertilized eggs and the eggs not fertilized by the 1st insemination. The results of in vitro fertilization of the mouse eggs treated by using micromanipulation and acid tyrode's solution with capacitated epididymal spermatozoa were as follows. In the case of ovulated unfertilized eggs, according to sperm count(106, 105, 104 and 103/ml) the rates of in vitro fertlilization treated by zona drilling were 86.0%, 82.0%, 70.0% and 54.0%, respectively, and those of control were 58.0%, 52.0%, 12.0% and 8.0%, respectively. The rates of in vitro fertilization of zona drilled eggs were significantly high compared with those of control, and there were no significant difference between two groups. According to the sperm count the zona drilled eggs developed to the blastocysts were 51.4%, 40.5%, 23.3% and 17.4% and those of control were 35.7%, 26.3%, 0% and 0%, respectively. Also, in the eggs not fertilized by 1st insemination, the fertilization rates of oocytes reinseminated after zona drilling was significantly higher(83.5%) than that of control(34.7%), and the rates of polyspermy were similar. The rates of development to the blastocysts was 18.6% in the zona drilling treated eggs, and that of control was 27.3%, there was no significant difference between two groups. These results indicated that oocytes not fertilized by 1st insemination as well as ovulated unfertilized eggs could be fertilized, improve fertilizing rates by zona drilling treatment, and development potential were normal.

• Development and Reproduction
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• v.7 no.1
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• pp.15-22
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• 2003

The Fas antigen (Fas) as a cell-surface receptor protein which mediates apoptosis-inducing signals plays an important role in the immune system. Expression of Fas mRNA is detected not only in lymphoid organs but also in the nonlymphoid organs. In the ovary, most of the follicles is known to undergo atreisa through apoptosis. However, the exact mechanism of atresia was not elucidated yet. Therefore, the purposes of the present study were to investigate the expression of Fas and Fas ligand in mouse ovary and to clarify the relationship between expression of Fas and Fas ligand and atresia of follicle. The result of RT-PCR demonstrated that Fas and Fas ligand mRNA was expressed in ovary, especially granulosa cells and oocytes. The immunohistochemistry showed that the granulosa cells and oocytes in growing follicles were stained for Fas and Fas ligand, but primordial follicles were not. Furthermore, Fas and Fas ligand were intensively stained in the atretic follicles As results of TUNEL staining to detect apoptotic cells in the ovaries, the number of TUNEL-positive (apoptotic) granulosa cells and oocytes increased in the atretic follicles compared to the healthy normal follicles. These results demonstrate that there is the positive relationship between expression of Fas and Fas ligand in granulosa cells and oocyies and apoptosis of them leading to atresia of follicles. It suggests that expression of Fas and Fas ligand could be associated with atresia of follicles in mouse ovary.

• Development and Reproduction
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• v.7 no.2
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• pp.95-103
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• 2003

Intracellular calcium is an important physiological factor in most cells, and ruthenium red and ryanodine play an important role as calcium modulators. Ruthenium red inhibits calcium-induced calcium release(CICR) from the intracellular calcium store. Ryanodine activates calcium release through ryanodine channel. The present experiment was performed to investigate the effects of two modulators on calcium ion metabolism and to determine their dose-dependency in oocyte and early embryo of mouse. Intracellular calcium ion concentration was measured in realtime by using confocal laser scanning microscope(CLSM) after loading of Fluo-3/AM in mouse oocytes and early embryos. Ruthenium red decreased intracellular calcium ion concentration in oocytes and early embryos at its high concentration(30, 300 $\mu$M). Ryanodine increased intracellular calcium ion concentration in oocytes and early embryos in low concentration(0.01 $\mu$M) but decreased that at higher concentrations(1, 10 $\mu$M). These results indicate that two modulators affected calcium ion metabolism in oocyte and early embryo of mouse, and their dose-dependency was different from somatic cell including myocytes.

• Journal of Animal Science and Technology
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• v.48 no.3
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• pp.353-360
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• 2006

This study was performed to investigate the effects of artificial stimulation on the increase of the oocyte activation, to evaluate the expression of cyclin B1 protein levels in enucleated mouse oocytes, and to investigate correlation between the oocyte activation and the cyclin B1 protein levels. The oocyte activation was induced by 7% ethanol (EtOH) or 10μg/ml Ca-ionophore with or without 10μg/ml cycloheximide (CH). The activation rate was significantly higher in both single (p<0.05) and combined (p<0.01) stimulated groups compared to control group. The cyclin B1 protein level was significantly reduced in both stimulated groups (p<0.05), except for EtOH+CH treatment group. The expression of cyclin B1 protein showed a higher negative correlation with activation rate in EtOH+CH (r=0.61, p<0.05) and Ca+CH (r=0.86, p<0.01) stimulation groups, but not in a both single stimulation groups. Taken together, it can be suggested that single (EtOH and Ca- ionophore) and combined (EtOH+CH and Ca+CH) stimulation increases the oocyte activation, especially combined stimulation, because it induces the degradation of cyclin B1 protein after artificial stimulation treatments in mouse oocytes.

• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.369-375
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• 2002

A sperm factor(s) for oocyte activation during fertilization has not been clearly identified. In this study to elucidate an oocyte activation factor(s), mouse sperm were sonicated and ultra-filtered with a 30 kilo-daltons (KD) cutoff membrane and the ultra-filtrate was then sequentially fractionated over Suporose 12 column and Superdex column, The recovered fractions were micro-injected into Mⅱmouse oocytes and second polar body formation (PBF) was examined. Suporose fraction RV2.10 prepared from sperm extract significantly increased PBF. Of Superdex fractions re-separated from Suporose fraction RV2.10, fraction RV2.12 also had the strongest PBF activity. By analyzing with micro-reverse phase column (URPC), the Superdex fraction RV2.12 appeared to be glutamic acid. In microinjection test, glutamic acid significantly increased PBF. This study suggests that glutamic acid should be a type of sperm factor for second polar body formation related to oocyte activation.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2006.10a
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• pp.111-112
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• 2006

• Journal of Embryo Transfer
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• v.27 no.4
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• pp.205-209
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• 2012

Transgenic rats and mice are useful experimental animal models for medical research including human disease model studies. Somatic cell nuclear transfer (SCNT) technology is successfully applied in most mammalian species including cattle, sheep, pig and mouse. SCNT is also considered to increase the efficacy of transgenic/knockout mouse and rat production. However, in the area of reproductive biotechnology, the rodent model is inadequate because of technical obstacles in manipulating the oocytes including intracytoplasmic sperm injection and SCNT. In particular, success of rat SCNT is very limited so far. In this review, the history of rodent cloning is described.

• Clinical and Experimental Reproductive Medicine
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• v.13 no.2
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• pp.201-206
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• 1986

These experiments were conducted to know whether RNA syntheis is involved in the cumulus expansion and oocyte maturation of mouse cumulus-oocyte complexes in vitro. Mouse cumulus-oocyte complexes(COC's) were cultured in the presence of cordycepin, an inhibitior of RNA synthesis and its effect on the cumulus expansion and oocyte maturation were examined. The results were as follows. 1. Continuous presence of cordycepin in the medium(200${\mu}g/ml$) inhibited the HCG-induced cumulus cell expansion of mouse complexes. This inhibition was reversible. 2. When the COC'S were preincubated with different concentration of cordycepin plus HCG for 3 hours and then transferred to the plain medium, the HCG induced cumulus expansion was suppressed at $100{\mu}g/ml$ of cordycepin. 3. When the COC'S were cultured with cordycepin after HCG stimulation(3hrs), the cumulus expansion were not suppressed by cordycepin. 4. Oocyte meiotic maturation did not appear to be affected by cordycepin. The data presented here imply that RNA synthesis is involved in the cumulus expansion process and that mouse oocytes are more resistant to RNA synthesis inhibitor than cumulus cells.