• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1342-1351
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• 2001

Over the years, the embryo transfer industry has grown from the simple collection & transfer of embryos into an advanced field of embryo biotechnology. Currently a large demand exists for bovine oocytes and early embryos in both research and commercial settings. Bovine embryos can now be produced in-vitro. Primary oocytes collected from antral follicles of abattoir - obtained ovaries can be induced to undergo the maturation process. In-vitor maturation system, however must ensure that the resulting oocyte is capable of undergoing normal fertilization and yields a zygote competent of developing to term after embryo transfer. Sperm preparation for IVF has improved with the use of heparine. The use of co-culture system has proved beneficial in circumventing the developmental block in IVM/IVF bovine embryos.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.866-871
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• 2007

Testis-specific protein (TSPY) is a Y-specific gene, with up to 200 copy numbers in bulls. In order to make bovine embryo sexing under farm condition more feasible, the possibility of using a non-electrophoretic method to detect the TSPY gene for sexing bovine early embryos was examined. Primers were designed to amplify a portion of the TSPY gene and a common gene as an internal control primer. PCR optimization was carried out using a DNA template from bovine whole blood. Furthermore, embryo samples were diagnosed by this method and the sexing results were contrasted with those of the Loop-Mediated Isothermal Amplification (LAMP) method. The results showed that TSPY was as reliable a sexing method as LAMP. Forty-three morula and blastocyst embryos collected from superovulated donor dairy cattle were sexed by this method, and twenty-one embryos judged to be female embryos were transferred non-surgically to recipients 6 to 8 days after natural estrus. Out of 21 recipients, 9 were pregnant (42.86%) and all delivered female calves. The results showed that the sex predicted by this protocol was 100% accurate. In conclusion, the TSPY gene was a good male specific marker and indicated that a non-electrophoretic method was feasible and accurate to detect the TSPY gene for sexing preimplantation bovine embryos.

• Reproductive and Developmental Biology
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• v.30 no.4
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• pp.307-311
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• 2006

The purpose of this study was to determine effects of oxytocin and $interleukin-1{\alpha}$ on in vitro development of bovine embryo cultured with endometrial epithelial and stromal cells isolated from bovine uterus. The expressions of COX-2 mRNA in bovine endometrium were also studied. When embryos were cultured with epithelial cells, the rate of blastocysts was significantly (p<0.05) higher in embryos treated with oxytocin than that of control group. The rate of hatched blastocysts was also significantly (p<0.05) higher in embryos treated with oxytocin than those of two control groups. On the other hand, when the embryos were cultured with stromal cells, the rate of blastocysts were significantly (p<0.05) higher than those of groups treated with $IL-1{\alpha}$, oxytocin and control with stromal cells than that of control group without stromal cells. The rate of blastocysts hatched were also significantly (p<0.05) higher in group treated with $IL-1{\alpha}$ than those of control group without stromal cells and oxytocin group. In another experiment, COX-2 gene was expressed in embryo group treated with oxytocin during the co-culture of embryos with epithelial cells. In contrast, COX-2 mRNA was expressed in group treated with $IL-1{\alpha}$ when the embryos were cultured with stromal cell. This result shows that oxytocin and $IL-1{\alpha}$ were stimulate embryo development in vitro when embryos were cultured with epithelial and stromal cells, and can affect the development of bovine embryos in the uterus.

• Journal of Embryo Transfer
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• v.12 no.1
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• pp.27-36
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• 1997

The studies were carried out to investigate the effects of co-culture with cumulus cells and oviduct epithelial cells on the in vitro fertilization and cleavage rate of bovine follicular cocytes and to determine the optimum thawing temperature and equilibration time on in vitro developmental rate of frozen bovine embryos. The ovaries were obtained from slaughtered Korean native cows. The follicular oocytes were cultured in TGM-199 medium containing 10 IU /ml의 PM SG, 10 IU /ml의 hCG, ip g/ml의 $\beta$-estradiol and 10% FCS for 24~48 hrs in incubator with 5% $CO_2$ in air at 38.5$^{\circ}C$. The bovine embryos following dehydration by cryoprotective agents and a various concentration of sucrose were directly plunged into liquld nitrogen and thawed in 3$0^{\circ}C$ water. Survival rate was defined as developmental rate on in vitro culture or FDA-test. The results are sunanarized as followes :1. The in vitro fertilization and in vitro developmental rates of bovine oocytes co-cultured with cumulus cells in TCM499 medium were 75.0~76.8% and 17.3~27.6%, respect-ively. And in-vitro fertilization rates of cumulus-enclosed oocytes(55.4%)were significantly(p<0.05) higher than cumulus-denuded oocytes (23.1%). 2. The in vitro fertilization and in vitro developmental rates of bovine oocytes co-cultured with l$\times$ l04cells /ml, 1 x l06cells /ml, lx l08cells /ml and 1 x l015cells /ml oviduct epithelial cells in TCM-199 medium were 74.5~77.8% and 15.7~21.20 respectively.3. The in-vitro fertilization and in vitro developmental rates of bovine oocytes cocultured in '1CM-199 media containing PMSG, hCG, PMSG+hCG. PMSG+$\beta$-estradiol, hCG+$\beta$-estradiol 0 to 40 hrs after insemination were 74.0~77.4% and l8.9~23.l%, re-spectiv ely.4.The survival rates of bovine embryos thawed after rapid freezing in the freezing medium containing a various concentration of sucrose added 1.5M and 2.OM glycerol,DMSO and propanediol were 23.5~31.4% and 20.6~34.l%, respectively. 5. The temperature thawed at 3$0^{\circ}C$ after rapid freezing of bovine embryos resulted in a significantly higher embryos survival rate than did at 2$0^{\circ}C$ and 35$^{\circ}C$.6. The equilibration time on the survival rates of bovine embryos was attained after short period of time(2.5~5 min.) in the freezing medium higher than long period of time (10~20min.). (Key words : bovine embryos, co-culture, freezing, in vitro development)

• Journal of Embryo Transfer
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• v.9 no.3
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• pp.221-227
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• 1994

This study was conducted to examine the condition of in vitro culture system and the viability after embryo transfer of in vitro matured-in vitro fertilized (IVM-IVF) bovine embryos. The in vitro development to the blastocyst stage was enhanced by supplying bovine serum albumin(BSA) to co-culture medium with bovine oviduct epithelial tissue(BOET) compared with that in medium supplemented with fetal bovine serum(FBS) (41.2% vs. 26. 3%, P<0.05). After transfer of IVM-IVF blastocysts into the uterine horn of recipient females (Aberdeen Angus), one was pregnant to term and produced a head of male Korean native calf. These results confirm that the in vitro development of IVM-IVF bovine embryos is affected with different protein source in co-culture with BOET, and IVM-IVF embryos can develop to term after in vitro culture and embryo transfer.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.11-11
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• 2001

In this study, we examined the developmental potential of reconstructed bovine embryos and the fate of donor mitochondria during their preimplantation development after nuclear transfer. Isolated cumulus cells were used as donor cells in nuclear transfer. Cumulus cells labelled with MitoTracker Green FM fluorochrome were injected into enucleated bovine MII oocytes and cultured in vitro. MitoTracker labelling on donor cells did not have a detrimental effect on blastocyst formation following nuclear transfer. Cleavage rate was about 69%(56/81) and blastocyst formation rate was 6.2% (5/81) at 7 days after nuclear transfer. The labelled mitochondria dispersed to the cytoplasm and became distributed among blastomeres and could be identified up to the 8- to 15-cell stages. Small patches of mitochondria were detected in some 8- to 15-cell stage embryos (5/20). However, donor mitochondria were not detected in embryos at the 16-cell stage and subsequent developmental stages. In the control group, mitochondria could be identified in arrested 1-cell embryos up to 7 days after nuclear transfer These results suggest that donor mitochondria disappear from recipient cytoplasm before 16-cell stage following nuclear transfer in reconstructed bovine embryos.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.95-102
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• 1997

The studies on the carried out to investigate the effective concentration of cryoprotectant agents and sucrose by one-step straw method of bovine embryos. The follicular oocytes were cultured in TCM-199 medium containing 10 IU/ml PMSG(Sigma, USA), 10 IU/ml hCG(Sigma, USA), 1$\mu\textrm{g}$/ml $\beta$-estradiol(Sigma, USA) and 10% FCS for 24~48 hrs in incubator with 5% CO2 in air at 38.5$^{\circ}C$ and then matured oocytes were again cultured for 12~18 hrs with motile capacitated sperm by preincubation of heparin. The bovine embryos following dehydration by cryoprotective agents and various concentrations of sucrose were directly plunged into liquid nitrogen and thawed in 3$0^{\circ}C$ water. Survival and in vitro developmental rate was defined as devellpmental rate on in vitro culture or FDA-test. The results are smmarized as followes : 1. The high in vitro developmental rates of bovine frozen embryos after rapidly thawed in freezing medium was attained 2.0M glycerol, 2.0M DMSO, 1M or 2.0M propanediol. 2. The high in vitro developmental rates of bovine frozen embryos after rapidly thawed in freezing medium was obtained single cryoprotectant(6.7~17.4%) than mixed cryoprotectants(6.7~16.7%). 3. In vitro developmental rate of bovine embryos after rapid frozen-thawing in the freezing medium added 0.25M and 0.50M sucrose were higher cleavage rate than those of sucrose concentration of 0.75M and 1.00M. 4. The freezing methods on in vitro developemental rates of bovine embryos was attained slow freezing method(9.70~15.6%) higher than rapid freezing method(9.4~13.3%).

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.65-71
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• 1994

This study were carried out to investigate the effective concentration of cryoprotectant agents and sucrose by one-step straw method, and to determine the optimum thawing temperature and equilibration time of frozen bovine embryos. The bovine embryos following dehydration by cryoprotective agents and a various concentration of sucrose were directly plunged into liquid nitrogen and thawed in 3O$^{\circ}C$ water. Survival rate was defined by FDA test. The results are summarized as follows : 1. The survival rate of bovine embryos thawed after rapid freezing in the freezing medium containing a various kinds of cryoprotective agents added 0.25M and O.50M sucrose were 28.6% and 25.0%, 35.1% and 31.6%, 32.4% and 24.4%, 34.2% and 28.2%, 18.9% and 17.6%, 14.7.% and 21.6%, respectively. 2. The survival rate of bovine embryos thawed after rapid freezing in the freezing medium containing a various concentration of sucrose added 1.5M and 2.OM glycerol, i.5M and 2.OM DMSO and 1.5M and 2.OM propanediol were 22.9~37.8%, 2O.7~31. 3%, 19.2~30.0% and 17.2~25.0%, respectively. 3. The temperature thawed at 2$0^{\circ}C$ after rapid freezing of bovine embryos resulted in a significantly higher embryos survival rate than did at 3$0^{\circ}C$ and 35$^{\circ}C$. 4. The equilibration time on the survival rate of bovine embryos was attained after short period of time(2.5~5 min.) in the freezing medium higher than long period of time (1O~20 min.).

• Journal of Embryo Transfer
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• v.12 no.3
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• pp.283-291
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• 1997

In vitro development of bovine embryos is affected by many factors such as energy substrates, amino acids, and some growth factors. It has been reported that mRNA of insulin, PDGF and their receptors are detected in cow embryos, and that some chelating agents such as EDTA and transferrin have beneficial role on mouse and bovine embryos. The author hypothesized that insulin, transferrin arid PDGF added to a culture medium increase in vitro development of bovine embryos by chelating toxic substance(s) or increasing cell growth and metabolism. Immature oocytes from slaughtered ovaries of Holstein cows and heifers were matured for 24 hours in a TCM199 containing 10% fetal calf serum, FSH, LH and estradiol with granulosa cells in vitro. Matured oocytes were coincubated with sperm for 30 hours in a modified Tyrode's medium (IVF). Embryos cleaved to 2- to 4-cell at 30 hours after IVF were selected and cultured in a 30-$\mu$l drop of a synthetic oviduct fluid medium (SOFM) containing 0.8% BSA, Minimum Essential Medium essential and non-essential amino acids, and insulin, transferrin or PDGF for 9 days. Supplementation of a SOFM with insulin, and /or transferrin did not increase develop-mental rate to expanding and hatching blastocyst of 2- to 4-cell bovine embryos compared with control. The highest developmental rate to hatching blastocyst was shown when PDGF was added at the concentration of 10 ng /ml among the supplementing doses tested in the present study (p<0.05). Addition of PDGF without insulin to a SOFM could not increase embrye development, but combined addition of PDGF with insulin significantly increased (p<0.05) embryo development to hatching blastocyst (50%) compared with control (38%). In conclusion, insulin and PDGF supplemented to a SOFM may act synergistically and have beneficial effect on in vitro development of 2- to 4-cell bovine embryos matured and fertilized in vitro.

• Korean Journal of Animal Reproduction
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• v.18 no.2
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• pp.113-119
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• 1994

To improve nuclear transplantation(NT) efficiency and to produce a large scale genetically identical cloned calves, examined the in vitro development capacity after co-culture of bovine oviductal epithelial cells (BOEC) and granulosa cells in TCM-199 supplemented with 10% fetal calf serum (FCS) with early bovine embryos derived from in vitro matured fertilized(IVM-IVF) oocyte. In addition, the age dependence of IVM oocyte on electro-stimulation and the effective electric voltage on in ivtro development of bovine NT embryos were examined. The results obtained were summerized as follows; 1. The cleavage rates of IVM-IVF bovine embryos in co-culture with bovine oviductal epithelial cells and granulosa cells were not significantly different(P<0.05), but the developmental rate into morula and blastocyst stage were different showing 38.3 and 20.2%, respectively. 2. The activation (82.5%) and development in vitro(8.6%) into later embryo stages of the aging oocytes of 32 hours post-maturation (hpm) were significantly higher than those of 24 hpm at direct current (DC) voltage of 1.5kV/cm, 60$\mu$sec pulse duration and 1 pulse time. 3. The fusion rates of NT eggs of 32 hpm following to different DC voltages from range 0.75 to 1.5kV/cm were not differ, but the developmental rate into morula and blastocyst stages at DC voltages of 0.75 and 1.0kV/cm were higher(11.4 and 12.6%, respectively) than those of 1.5kV/cm(0%). From these results, it can be suggested the optimal culture system for in vitro culture of IVM-IVF bovine embryos is a co-culture system with BOEC in TCM-199 supplemented 10% FCS. The effective time and the DC voltage for activation, electrofusion and in vitro development of NT embryos derived from IVM-IVF bovine embryo are 32hpm and 0.75~1.0kV/cm. But to improve NT efficiency, the advanced research (cell cycle synchronization, micromanipulation, culture system, etc.) is needed.