• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.80-80
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• 2003

In cryopreserved rat embryos, survival rates obtained in vitro are not always consistent with the rates obtained in vivo. To determine the optimal conditions for in vivo development to term, rat embryos at the 4-cell, 8-cell and morula stages were vitrified in EFS40 by a 1-step method and transferred into oviducts or uterine horns of recipients at various times during pseudopregnancy. Vitrified and fresh 4-cell embryos only developed after transfer into oviducts of asynchronous recipients on Day -1 to -2 of synchrony, i.e., at a point in pseudopregnancy that was 1-2 days earlier than the embryos. However, although about half the vitrified embryos transferred into oviducts on Day -1 developed to term, only a minority of embryos transferred at later times did so, whether vitrified (10-34%) or fresh (24-33%), suggesting that this may not be the most suitable stage for cryopreservation. Very few 8-cell embryos, either vitrified or fresh, developed when transferred into oviducts on Day 0 to -0.5. However, when transferred into uterine horns, high proportions of vitrified 8-cell embryos (-63%) developed to term in reasonably synchronous recipients (Day 0 to -0.5) but not in more asynchronous ones (6%; Day-1). A majority of vitrified morulae also developed to term (52-68%) in a wider range of recipients (Day 0 to -1), the greatest success occurring with recipients on Day -0.5. Similar proportions of vitrified and fresh 4-cell embryos, 8-cell embryos and morulae developed to term when there was appropriate synchronization between embryo and recipient. Thus vitrification of preimplantation stage rat embryos does not appear to impair their developmental potential in vivo.

• Development and Reproduction
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• v.19 no.1
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• pp.53-60
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• 2015

Environmental conditions during early mammalian embryo development are critical and some adaptational phenomena are observed. However, the mechanisms underlying them remain largely masked. Previously, we reported that AQP5 expression is modified by the environmental condition without losing the developmental potency. In this study, AQP11 was examined instead. To compare expression pattern between in vivo and in vitro, we conducted quantitative RT-PCR and analyzed localization of the AQP11 by whole mount immunofluorescence. When the fertilized embryos were developed in the maternal tracts, the level of Aqp11 transcripts was decreased dramatically until 2-cell stage. Its level increased after 2-cell stage and peaked at 4-cell stage, but decreased again dramatically until morula stage. Its transcript level increased again at blastocyst stage. In contrast, the levels of Aqp11 transcript in embryos cultured in vitro were as follows. The patterns of expression were similar but the overall levels were low compared with those of embryos grown in the maternal tracts. AQP11 proteins were localized in submembrane cytoplasm of embryos collected from maternal reproductive tracts. The immune-reactive signals were detected in both trophectoderm and inner cell mass. However, its localization was altered in in vitro culture condition. It was localized mainly in the plasma membrane of the blastocysts contacting with external environment. The present study suggests that early stage embryo can develop successfully by themselves adapting to their environmental condition through modulation of the expression level and localization of specific genes like AQP11.

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.411-417
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• 1998

The objective of this study was to dertermine the effects of oviductal fluid and oviductal conditioned medium on polyspermy and in vitro development of porcine oocytes. The addition of oviductal fluid and oviductal conditioned medium in the prefertilization and fertilization medium significantly decreased polyspermy rates and the mean number of spermatozoa in penetrated eggs(P＜0.05). The acrosome reaction rate significantly increased when spematozoa were exposed for 1.5, 3, 4.5h in oviductal fluid and oviductal conditioned medium(P＜0.05). When oocytes cultured for 192h, the percentage of oocytes that developed to the morula and blastocyst stage was higher in culture medium with oviductal fluid and oviductal conditioned medium than without oviductal fluid and oviductal conditioned medium(P＜0.05). These results indicated that the oviductal secreations will effectively reduce both the polyspermy rates and the mean number of spermatwa in penetrated eggs. And the presence of culture with oviductal fluid and oviductal conditioned medium promotes in vitro development of porcine oocytes.

• Journal of Embryo Transfer
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• v.6 no.1
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• pp.13-24
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• 1991

The objective of this experiment was to study some possibilities to simplify freezing, thawing and transfer procedure of one-step straw method comparing with the conventional methods using bovine embryos. The previous work are also designed to investigate the thawing effect by development stage and its quality using the embryos. Results obtained were summarized as follows: 1. A total of 87 embryos from 14 donor cows were frozen-thawed and an average of frozen embryo/donor was 6.2. 2. The survival rates of morula stage(65.4%) were higher than those of blastocyst stage(57.l%) and vice versa in rate of morphological recovery (80% vs 95.4%). However. no significant difference was denoted between them. 3. In difference between the groups of good quality and poor quality. good quality was resulted in a significantly higher embryo survival rate(75%) and recovery rates(95%) than poor quality(P<0.0l). 4. In effects of non-permeable sugar dilution in added to l.0M glycerol. higher survival rates were orderd in sucrose. lactose, raffinose and xylose. But lactose-raffinose, sucrose-trehalose and xylose in added to 2.OM glycerol. 5. The highest survival rates were obtained by direct plunge into the liquid nitrogen with 3.OM concentration both of glycerol and trehalose. 6. The survival rates in vitro condition of one-step and direct plunge methods(75%-87.5%) were significantly higher than those of multiple steps (21.4-52.6%) in in vitro (P<0.0l). However, the results of single-step were critical in comparing to other steps of final pregnant conformation.

• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.179-188
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• 1993

The developmental capacity of bovine oocytes under three different culture systems was investigated in this experiment ; One was culture in TCM199 with bovine oviductal epithelial cells(BOEC) for in vitro culture, another was culture in TCM199 with BOEC for 2 days and then transfer of 4~8cell embryos to rabbit oviduct(RO) and the other was transfer of 1 or 2cell embryos to RO for in vivo culture. And the other concern of this experiment was to investigate the effect of culture period and transfer site on recovery. Immature bovine oocytes were cultured in TCM199 with granulosa cells for 22-24hrs and then fertilized in vitro using frozen-thawed semen treated with BO-caffine and BO-BSA. Fifteen to 18hrs after in vitro fertilization oocytes were cultured in TCM199 with BOEC or transferred to RO for 5 days. The rate of development to the morula or blastocyst was higher in transfer of 1 or 2cell embryos to RO(23.1%) than culture in TCM199 with BOEC(11.7%). But, there was no difference between transfer of 1 or 2cell embryos and transfer of 4~8cell embryos to RO(12.8%). Recovery under different culture periods in RO was significantly higher in 90~95hrs(70.1%) than 122~125hrs(50.9%, p<0.05) and recovery significantly increased when oocytes were transferred deeper in RO(2.5cm>, 47.7% ; 2.5~4.5cm, 63.9% ; 4.5cm<, 77.3%, p<0.05). The results show that transfer of 1 or 2cell embryos to RO is an effective means of supporting the further development of in vitro matured and fertilized bovine oocytes than culture in TCM199 with BOEC or transfer of 4~8cell embryos to RO, and recovery from RO increases when oocytes are transferred deeper and incubated shorter in RO.

• Journal of Aquaculture
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• v.15 no.1
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• pp.39-42
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• 2002

Water temperature, at which Spisula sachdinensis egg successfully completed development ranges from 10 to $25^{\circ}C$. Within this range, the development duration is reduced with increasing temperature. The relationships between temperature (WT, $^{\circ}C$) and the required time (t: hour) from egg to each developmental stage are described as follows: 2-cell : 1/t = 0.0554 WT -0.3769; 8-cell : 1/t = 0.0210 WT -0.1142; Morula : 1/t = 0.0125WT -0.0712; Trochophore : 1/t = 0.0039 WT -0.0203; D-shaped larva : 1/t = 0.0024W T -0.0108. Biological minimum temperature for the egg development is 5.5$^{\circ}C$.

• Korean Journal of Animal Reproduction
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• v.27 no.4
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• pp.309-315
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• 2003

DNA methylation at CpG sites, which is a epigenetic modification, is associated with gene expression without change of DNA sequences. During early mouse embryogenesis, dynamic changes of DNA methylation occur. In this study, DNA methylation patterns of porcine embryos produced in vivo and in vitro were examined at various developmental stages by the immunocytochemical staining method. Interestingly, active demethylation was not observed on the paternal pronucleus of porcine zygotes. However, differences were detected in the passive demethylation process between in vivo and in vitro embryos. There was no change in the DNA methylation state until the blastocyst stage of in vivo embryos, whereas partial demethylation was observed in several blastomeres from a 4 cell stage to a morula stage of in vitro embryos. The whole genome of inner cell mass (ICM) and trophectoderm (TE) cells in porcine blastocysts were evenly methylated without de novo methylation. Our findings demonstrate that genome-wide demethylation does not occur in pig embryos during preimplantation development unlike murine and bovine embryos. It indicates that the machinery regulating epigenetic reprogramming may be different between species.

• Reproductive and Developmental Biology
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• v.35 no.3
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• pp.203-207
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• 2011

The objective of this study was to determine the effect of semen extenders on the motility, viability and fertility in vitro of spermatozoa during storage of fresh boar semen diluted in different commercial extenders used for pig artificial insemination (AI). In this experiment, semen were diluted in Androhep plus, Beltsville Thawing Solution (BTS), Modena, Seminark and Vitasem LD. Five ejaculates were collected from three Duroc boars and sub-samples were diluted ($30{\times}10^6$ spermatozoa/ml) in different extenders. Semen was stored at $170^{\circ}C$ for 10 days. Sperm motility and viability was assessed using Computer-Assisted Semen Analysis (CASA) and flow-cytometry on 1, 3, 5 and 10 day post collection The motility of spermatozoa stored in different extenders was gradually decreased by increasing the duration of storage of semen. However, there was not significant1y different in the sperm motility and viability among other extenders. On the other hand, the in vitro-matured oocytes were fertilized and cultured in vitro to assess the fertility of boar spermatozoa stored for 3 and 10 days in different extenders. The percentage of morula and blastocyst were taken as indicators of fertility in vitro of spermatozoa. Therefore, there were no differences in the rate of embryos developed to the molular and blastocyst stage. There were no differences in the motility and fertility in vitro among 5 kinds of commercial boar semen extenders.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.191-196
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• 1996

The objective of this study were to investigate the effects of culture media and additives on the development of bovine in vitro matured(IVM) and in vitro fertilized(IVF) oocytes. In experiment 1, bovine oocytes were cultured in droplets of TC 199 supplemented with 10% fetal bovine serum(FBS) with or without hormones (5$\mu\textrm{g}$/ml FSH, 5$\mu\textrm{g}$/ml LH, 1$\mu\textrm{g}$/ml E2). Cleavage rates of embryos cultured for 40~44hrs after IVF were higher when embryos were cultured in TC 199 supplemented hormones (68.1%, 921/35) than without hormones (52.7%, 77/146), but the percentages of development beyond morulae stage were not difference (20.7%, 19.4%). In experiment 2, the effects of various media such as TC 199, synthetic oviduct fluid(SOF), CR1aa with different energy source (fatal bovine serum, FBS; bovine serum albumin, BSA) on developmental capacity of IVM/IVF bovine embryos were investigated. The developmental rates into morulae and blastocysts were 27.1, 10.7, 6.3 and 0%, respecitvely, in CR1aa plus 3mg/ml BSA, SOF plus 10% FBS, TC 199 plus 10% FBS, SOF plus 3mg/ml BSA. In experiment 3, the comparisons of bovine embryos developed to morulae and blastocysts in different culture media (TC 199, SOF, CR1aa, Menezo's B2) were investigated. The developmental capacity beyond morulae stage were 32.9, 26.6, 11.1 and 7.1%, respectively, in Menezo's B2 plus BSA, CR1aa plus BSA, SOF plus BSA, TC 199 plus FBS medium. The cell numbers of the blastocyst were not different in different cultrue media. In experiment 4, bovine embryos were co-cultured with vobine oviduct epithelial cells(BOEC) in TC 199 plus FBS, SOF plus BSA, CR1aa plus BSA, Menezo's B2 plus BSA. The morula and blastocyst rates were 44.7, 32.9, 26.0 and 23.3%, respectively, in CR1aa TC 199, SOF, and Menezo's B2 medium. The cell numbers of the blastocyst were similar to those of blastocyst developed in different culture media.

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.163-170
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• 1996

The effect of several potential antioxidants and amino acids were examined as a means of increasing the development of in vitro matured and in vitro fertilized oocytes into morulae or blastocysts. Bovine embryos developed to the 2~8 cell stage after in vitro fertilization were cultured for 5 to 6 days at 39$^{\circ}C$ in CR1aa containing varing concentraton of the antioxidants and amino acid in a gas phase consisting of 5% CO2, high humidified air. At 5~6 days, embryo developments were reduced, and embryos were fixed and stained with Hochest 33342 DNA stain to facilitate counting of cells. In experiment 1, the proportion of embryos developed to morulae and blastocysts in CR1aa containing 1mM, 2.5mM taurine (22.6% and 20.4%) was slightly higher than those of 0, 5 and 10mM Taurine (5.7, 5.7 and 3.9%, P<0.05). In experiment 2, addition of glutathione did not improve blastocyst development (P>0.05). In experiment 3, concentations of superoxide dismutase(SOD) ranging from 300 to 1,000 U did not affect the propotion of embryos developing into blastocysts (P>0.05). In experiment 4, addition of 250 U catalase(38.5%) was slighty higher than those of 0, 500 and 1,000U. In experiment 5, the proportion of embryo developed beyond morula stage in CR1aa with taurine plus EDTA was slighty higher than other treatments(15.7, 26.0 and 29.2%), there were no significantly increases in cell number among treatments(P>0.05). These results are indicating that antioxidants and amino acids can increase the proportion of embryos that develop into morulae and blastocysts, but did not increas in cell number of blastocysts.