• Reproductive and Developmental Biology
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• v.35 no.4
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• pp.469-473
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• 2011

These study was carried out to investigate the effects of the supplementation with sodium nitroprusside (SN) and nitric oxide (NO) of canine oocytes on IVM rates. Oocytes were incubated in TCM-199 supplement with at 0.03~0.10 mM SN and 0.3~1.0 mM NO for 48 hrs. Oocytes were transferred to 50 ul drops of maturation medium covered mineral oil and cultured in a $CO_2$ incubator (5% $CO_2$, 95% air, $38^{\circ}C$). The in vitro maturation rate of oocytes cultured for 48 hrs in TCM-199 medium supplement with 0.03, 0.05, 0.07, 0.10 mM SN were $25.9{\pm}3.5%$, $36.4{\pm}3.2%$, $33.3{\pm}3.5%$, $28.8{\m}3.2%$, respectively. The in vitro maturation rate of oocytes cultured for 48 hrs in TCM-199 medium supplement with 0.03~0.07 mM SN were significantly increased compare to the control ($26.0{\pm}2.2%$). The in vitro maturation rates of oocytes cultured for 48 hrs in TCM-199 medium supplement with 0.3, 0.5, 0.7, 1.0 mM NO were $28.0{\pm}4.2%$, $36.5{\pm}3.6%$, $30.0{\pm}3.8%$, $19.2{\pm}3.5%$, respectively. The in vitro maturation rate of oocytes in TCM-199 medium supplemented with 0.3 and 0.5 mM NO were significantly increased compare to the control ($26.0{\pm}2.2%$). The in vitro maturation rates of oocytes cultured for 12~48 hrs in TCM-199 medium supplement with 0.05 mM SN were $26.0{\pm}3.2%$, $28.0{\pm}3.4%$, $38.0{\pm}3.2%$, respectively. The in vitro maturation rate of oocytes cultured for 12~48 hrs in TCM-199 medium supplement with 0.5 mM NO were $22.0{\pm}3.0%$, $30.0{\pm}3.8%$, $36.0{\pm}4.2%$, respectively. These result was significantly increased compare to the control.

• Clinical and Experimental Reproductive Medicine
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• v.38 no.1
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• pp.24-30
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• 2011

Objective: The objectives of this study were to analyze efficacy of immature and mature mouse oocytes after vitrification and warming by applying various combinations of cryoprotectants (CPAs) and/or super-rapid cooling using slush nitrogen ($SN_2$). Methods: Four-week old ICR female mice were superovulated for GV- and MII-stage oocytes. Experimental groups were divided into two groups. Ethylene glycol (EG) only group: pre-equilibrated with 1.5 M EG for 2.5 minutes and then equilibrated with 5.5 M EG and 1.0 M sucrose for 20 seconds. EG+dimethylsulfoxide (DMSO) group: pre-equilibrated with 1.3 M EG+1.1 M DMSO for 2.5 minutes and equilibrated with 2.7 M EG+2.1 M DMSO+0.5 M sucrose for 20 seconds. The oocytes were loaded onto grids and plunged into $SN_2$or liquid nitrogen ($LN_2$). Stored oocytes were warmed by a five-step method, and then their survival, maturation, cleavage, and developmental rates were observed. Results: The EG only and EG+DMSO groups showed no significant difference in survival of immature oocytes vitrified after warming. However, maturation and cleavage rates after conventional insemination were greater in the EG only group than in the EG+DMSO group. In mature oocytes, survival, cleavage, and blastocyst formation rates after warming showed no significant difference when EG only or EG+DMSO was applied. Furthermore, cleavage and blastocyst formation rates of MII oocytes vitrified using $SN_2$ were increased in both the EG only and EG+DMSO groups. Conclusion: A combination of CPAs in oocyte cryopreservation could be formulated according to the oocyte stage. In addition, $SN_2$ may improve the efficiency of vitrification by reducing cryoinjury.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.56-56
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• 2001

The exogenous gene transfer by intracytoplasmic sperm injection (ICSI) procedure has been recently used to produce transgenic mice and pigs. Sperm-mediated DNA transfer has the potential to markedly simplify the generation of transgenic animals. This method may serve as an alternative to the pronucleus injection of DNA for the production of transgenic pigs. Therefore, in this study, we investigated the expression of transgene after co-injection of spermatozoon or sperm head with green fluorescent protein (GFP) gene into in vitro matured porcine oocytes. Spermatozoon and sperm head, that was obtained by sonication, were treated with 0.03% Triton X-100 to remove the membrane. They were preincubated with linearized pEGFP-N1 for 1 min, and then embryos cultured NCSU23 medium for 2.5 days after co-injected of sperm and DNA. We monitored expression of GFP in embryos under epifluorescent microscope. The remove of sperm membrane did not alter the developmental competence of embryos after ICSI. At 7 days following injection, the rates of blastocysts following injection of intact sperm (15.0%), and of sperm with disrupted membrane (14.2%) were higher than that following IVF (10.0%). Porcine oocytes injected with sperm which co-cultured with DNA concentration of 1, 0.1, and 0.01 ng were 60, 65.7 and 75% and 18.5, 37.4 and 22.2% for rates of cleavage and GFP expression, respectively. In vitro matured porcine oocytes injected with sperm and isolated sperm head resulted in 69 and 59.7% of cleavage rates, respectively The rates of embryo GFP expressed did not significantly different between sperm (20.4%) and sperm head (20.0%) injection. The transgenic embryos with the clusters of positive blastomeres were observed under fluorescent microscope. Most of embryos expressed GFP gene showed mosaicism. They showed GFP expression at 1/4, 2/4 and 3/4 of blastomeres at the 4-cell stage. Among these 4-cell embryos, the expression rate of 1/4 blastomere group (54.6%) was higher than the other groups (15.3-30.7%). These results indicate that membrane disrupted sperm could attach with exogenous DNA, and that this procedure may be useful to introduce foreign gene into porcine oocytes. Therefore, our data suggest that the ICSI car be a useful tool to efficiently produce transgenic pig as well as other mammals.

• Reproductive and Developmental Biology
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• v.36 no.4
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• pp.255-260
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• 2012

The purpose of this study was to assess follicular viability and competence through in vitro culture of preantral follicles isolated from vitrified mouse whole ovaries. Mouse preantral follicles were enzymatically isolated from vitrified- warmed and fresh ovaries and cultured for 10 days followed by in vitro oocyte maturation. In vitro matured oocytes were fertilized and cultured to the blastocyst stage. Five minutes pre-exposure to vitrification solution of whole ovaries had significantly higher (p<0.05) oocyte survival and maturation rates than between 10 min exposure groups. Oocyte diameter was significantly smaller (p<0.05) in the 5 and 10 min exposure groups ($69.4{\pm}2.8$ and $67.8{\pm}3.1$) when compared to that of control group ($71.7{\pm}2.1$). There was no statistical significant difference in blastocyst development rates between vitrification group (8.6%) and the fresh control group (12.0%). The mean number of cells per blastocyst was significantly lower (p<0.05) in the vitrification group ($41.9{\pm}20.2$) than in the fresh control group ($55.1{\pm}22.5$). The results show that mouse oocytes within preantral follicles isolated from the vitrified whole ovaries can achieve full maturation, normal fertilization and embryo development.

• International Journal of Industrial Entomology and Biomaterials
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• v.26 no.2
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• pp.124-130
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• 2013

Bumblebees are widely used to pollinate various greenhouse crops. Among the different bumblebee species, Bombus ignitus is indigenous to Korea, China, Japan and Russia. B. ignitus undergoes one generation per year, and artificial hibernation is essential for year-round rearing of the bumblebee. Keeping the queens under low-temperature conditions for several months is an effective method for terminating their diapause and promoting colony development. In the present study, we investigated how cold temperature affects the artificial hibernation of B. ignitus queens. Under chilling temperatures of $-2.5^{\circ}C$, $0^{\circ}C$, $2.5^{\circ}C$ and $5^{\circ}C$ with constant humidity >80%, the queens stored at $2.5^{\circ}C$ exhibited the highest survival rates, which were 74.0% at one month, 67.0% at two months, 60.0% at three months, 46.0% at 4 months, 33.0% at 5 months and 24.0% at 6 months. Lower survival rates were observed at $0^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ and $12.5^{\circ}C$. At $2.5^{\circ}C$ the colony developmental characteristics after diapause were 1.2- to 1.5-fold greater than those when queens were stored at $5^{\circ}C$. Thus, $2.5^{\circ}C$ and 70% R.H. were the most favorable chilling temperature and humidity conditions for terminating the diapause of B. ignitus queens.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.6
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• pp.739-747
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• 2000

This experiment was conducted to evaluate the influence of dimethyl-sulfoxise (DMSO, 0, 5, 50, 100 and $500{\mu}M$) on the motility and acrosome reaction of the frozen-thawed spermatozoa from 3 different bulls (Bull A, Band C). Also we evaluated the developmental capacity of bovine embryos fertilized in a medium containing DMSO at various concentrations. DMSO had negligible effects on the sperm motility and acrosome reaction in all three bulls. However, the development rates from 2 to 16 cells stage on the 3rd day after insemination with 50, 100 and $500{\mu}M$ DMSO in Bull-B, and up to the blastocyst stage fertilized with 5, 50, 100 and $500{\mu}M$ in Bull-A were significantly higher (p<0.05) than those of control ($0{\mu}M$ DMSO) group from each bull. Furthermore, the rates of blastocysts per cleaved embryos of 5 to $500{\mu}M$ DMSO group in Bull-A and of 5 to $100{\mu}M$ DMSO in Bull-C were also significantly higher (p<0.05) than those for their $0{\mu}M$ groups, respectively. These results indicate that DMSO at micromol level used for in vitro fertilization might stimulate the development of embryos for some bulls.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.4
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• pp.495-499
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• 2006

In our previous studies, we demonstrated that Vascular Endothelial Growth Factor (VEGF) enhances bovine oocyte maturation and early embryonic development in serum supplemented media. In this experiment, to determine the synergistic effect of VEGF with serum components on early embryonic development in vitro in cattle, 1 mg/ml polyvinyl-alcohol (PVA) was replaced with foetal bovine serum (FBS) in maturation and culture media. Bovine oocytes were matured in Synthetic Oviduct Fluid (SOF) supplemented with PVA, PVA+5 ng/ml of VEGF, FBS, or FBS+VEGF. Fertilized oocytes were cultured in the same conditions for 8 days. The development of embryos was examined at 48 h post- insemination and on days 6, 7 and 8. The results were analyzed using repeated measures two- factor ANOVA, in which the effects of VEGF and serum were assigned as two factors. The development rate to 4- to 8-cell embryos at 48 h was significantly higher in the PVA+VEGF group than in the PVA group (44.7% and 31.5%, respectively). However, the highest development rate to 4- to 8-cell embryos was obtained from the FBS+VEGF group (58.8%). On day 8, the blastocyst rates were higher in the PVA+VEGF (22.8%), FBS (32.1%, p<0.05) and FBS+VEGF (42.1%, p<0.05) groups than in the PVA group (17.1%). Two- factor ANOVA of the development rates indicates that VEGF had a significant effect, but had no synergistic effect with serum components on early embryonic development. The results of the present study demonstrate that VEGF improves the in vitro developmental competence of bovine oocytes and/or embryos independent of the effect of serum components.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.1
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• pp.77-84
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• 2003

Objective : The aim of this study was to evaluate the influence of three different media on preimplatation embryo development and the expression of Bcl-2, Mcl-1, Bax, and Bok in mouse. Materials and Methods: Two-cell embryos were retrieved from ICR female mice (4 weeks old) at 48 hr after hCG injection and cultured in Ham's F-10, HTF, and G1.2 media. The developmental rate of 2-cell embryos was evaluated from 24 hr to 72 hr after culture. RT-PCR was performed for the detection of Bcl-2, Mcl-1, Bax, and Bok gene expression. Results: The rates of morula and blastocyst in HTF and G1.2 media (88%, 98.1%) were significantly higher than those in Ham's F-10 media (39.6%) at 48 hr. Likewise, the rates of hatching and hatched blastocyst in HTF and G1.2 media (21.9%, 52.9%) were higher than those in Ham's F-10 media (3.5%) at 72 hr. Bcl-2 and Bax mRNAs were highly detected in embryos cultured in Ham's F-10 when compared in embryos cultured in HTF and G1.2. In contrast, the expression of Mcl-1 and Bok was not significantly different. Conclusion: These results show that HTF and G1.2 culture media increase the rate of blastocyst formation and stimulate Bcl-2 and Bax gene expression in mouse preimplantation embryos.

• Development and Reproduction
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• v.12 no.2
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• pp.141-149
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• 2008

This study was conducted to develop an efficient cryopreservation method of human embryonic stem (ES) cells using vitrification. In an initial experiment, sub-clumps of human ES cells (CHA-hES3 and CHA-hES4) were vitrified using grids after incubation with STO feeder cells for 1 or 16 h (Groups 1-1 and 1-2, respectively). After storage for $2{\sim}4$ months, thawed clumps were re-plated on a fresh feeder layer. The survival rates of warmed CHA-hES3 and CHA-hES4 cells of Group 1-2 were significantly higher than those of the corresponding Group 1-1 cells. In the second experiment, human ES cells were vitrified after incubation with feeder or feeder-conditioned medium (Groups 2-1 to -7). Relative mRNA expression of BM proteins and survival rates were increased following incubation of ES cells with fresh feeder cells for 16 h. In conclusion, increasing of tight adhesion between ES cells by extended incubation with feeder could reduce cryoinjury after vitrifying/warming.

• Reproductive and Developmental Biology
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• v.29 no.1
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• pp.37-41
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• 2005

The aim of this study was to improve efficiency and quality of the production of Korean Native Cow embryos. We examined effects of ovarian morphology and maturation vessel on the development and cell number of blastocysts. The development rates to the 2-cell embryos from oocytes collected from the ovaries of different morphological statues were similar ranging between 70.3 and 84.1%. The development rate to the 8 cell- and blastocyst-stage embryos was the highest in the group without both corpus luteum (CL) and follicle. The inner cell mass (ICM), trophectoderm (TE) and total cell number (TCN) were significantly higher in the groups of follicular cyst and regressive CL than other treatment groups, and the same pattern was observed in the ICM/TCN ratio. The development rate to the 2-cell stage was significantly higher in 0.5-㎖ straw group than 0.25-㎖ straw group. However, the development rates to the blastocyst stage were similar between the dish and the straw group. There were no differences in the number of ICM and TE cells, TCN and ICM/TCN ratio of blastocysts from oocytes matured in the different vessels.