• Journal of Embryo Transfer
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• v.6 no.2
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• pp.18-29
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• 1991

Nuclear transplantation technique is known as the most potential and efficient method for producing a large number of genetically identical animals from a single embryo. The technical development of nuclear transplantation in mammals and its application to the production of cloned animals are described. For the efficient and successful production of cloned embryos by nuclear transplantation, the right selection and micromanipulation of recipient eggs or embryos as capacious recipient cytoplasm, the adequate and benefitlal preparation of multiple totipotent embryonic cells as donor nuclei, and also the fusion technique are very critical. Recent studies approaching to these critical points are introduced and discussed. Up to date, the overall efficiency of production of cloned embryos and offspring in livestock is estimated to be low. Further technical development of nuclear transplantation will enable large-scale production of cloned livestock and in near future the commercial cloning of animals will become a reality.

• Journal of Embryo Transfer
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• v.8 no.1
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• pp.37-44
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• 1993

Nuclear transplantation techinque has been found to be the most potential and efficient method for producing a large number of genetically identical animals from a single embryo. The technical development of nuclear transplantation in mammals and its application to the production of cloned animals were reviewed. For the efficient and successful production of cloned embryos by nuclear transplantation, selection and micromanipulation of recipient eggs or embryos as capacious recipient cytoplasm, and benefitial preparation of multiple totipotent embryonic cells as donor nuclei, and also fusion technique are very critical. Recent works approaching to these critical points were introduced and discussed.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2006.10a
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• pp.54-55
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• 2006

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2003.10a
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• pp.26-28
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• 2003

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2005.10a
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• pp.138-138
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• 2005

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2004.10a
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• pp.26-31
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• 2004

This work was undertaken in order to study the developmental competence of nuclear transfer cat embryo with fetal fibroblast and adult skin fibroblast as donor nuclei. Oocytes wererecovered by mincing the ovaries in Hepes-buffered TCM199 and selected the cumulus oocyte complexes (COCs) with compact cumulus cell mass and dark. Homogenous ooplasm were cultured for maturation in TCM199 + 10% fetal bovine serum (FBS) for 12 hours and used as a source of recipient cytoplast for exogenous somatic nuclei. In Experiment 1, we evaluated the effect donor cell types on the reconstruction and development of cloned embryos. Fusion, first cleavage and blastocyst developmental rate was not different between fetal fibroblast and adult skin cell (71.2 vs. 66.8; 71.0 vs. 57.6; 4.0 vs. 6.1 %, P<0.05). In Experiment 2, cloned embryos were surgically transferred into the oviducts of recipient queens. One of seven recipient queens was delivered naturally 2healthy cloned cats and 1 stillborn from fetal fibroblast cell of male origin after 65 days embryo transfer. One of three recipient queens was delivered naturally 1 healthy cloned cat from adult skin cell of female after 65 days embryo transfer. The cloned cats showed genotypes identical to the donor cell lines, indicating that adult somatic cells can be used for feline cloning.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.309-317
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• 2017

Melatonin (N-acetyl-5-methoxytryptamine) is an indole synthesized from tryptophan by the pineal gland in animal. The major function of melatonin is to modulate circadian and circannual rhythms in photoperiodic mammals. Importantly, however, melatonin is also a free radical scavenger, anti-oxidant, and anti-apoptotic agent. Recently, the beneficial effects of melatonin on oocyte maturation and embryonic development in vitro have been reported in many species such as pig, cattle, sheep, mouse, and human. In this review, we will discuss recent studies about the role of melatonin in the production of porcine and bovine oocytes and embryos in vitro in order to provide useful information of melatonin in oocyte maturation and embryo culture in vitro.

• Journal of Embryo Transfer
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• v.30 no.4
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• pp.345-350
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• 2015

In the last 10 years, porcine somatic cell nuclear transfer to generate transgenic pig has been performed tremendous development with introduction and knockout of many genes. However, efficiency of porcine somatic cell nuclear transfer is still low and embryo transfer (ET) is one of important step for production efficiency. In porcine ET for production of transgenic cloned pig, we can consider many of points to increase production rates. In respect of seasonality and weather, porcine ET usually is not performed in summer and winter. Cloned transgenic embryos must be transferred into reproductive tracts of recipients where embryos are located after natural fertilization with similar estrous cycle. If cloned embryos with 2~4 cell stage are transferred, they must be transferred into oviducts in periovulatory stage. Number and deposition sites of transferred cloned embryos are important. And we must compare the methods of ET between surgical and non-surgical ones in respect of production efficiency. Sow recipients after natural estrus is most preferred recipients however its cost is must be considered. Here we will review many of current studies about porcine embryo transfer to increase production efficiency of transgenic pigs and strategies for further studies.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.215-219
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• 2010

The objective of this study was to examine the reproductive characteristics of cloned miniature piglets produced from surrogate domestic pigs. Somatic cell nuclear transfer (SCNT) miniature pig embryos were transferred into domestic pigs. As controls, domestic pigs of the same breed with surrogates for SCNT embryos and miniature pigs of the same breed with the somatic cell donor were bred by artificial insemination and natural mating, respectively. Surrogate domestic pigs that farrowed cloned miniature piglets had a significantly longer gestation length (118.1 days) than conventionally bred domestic (115.4 days) and miniature (115.5 days) pigs. Furthermore, the birth weight of cloned miniature piglets produced from domestic pigs (743 g) was significantly greater than that of miniature piglets produced by natural breeding (623 g). Also, cloned miniature piglets had a significantly lower weaning rate (49.7%) than conventionally produced domestic (91.5%) and miniature (100%) piglets. No differences were observed between female and male cloned piglets in gestation length, litter size, birth weight, or weaning rate. Our results demonstrate that gestation length is extended in domestic pigs that are transferred with SCNT miniature pig embryos and that cloned miniature piglets have increased birth weight and high pre-weaning mortality.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.73-73
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• 2002

Nuclear transfer (NT) techniques have advanced in the last years, and cloned animals have been produced by using somatic cells in several species including pig. However, it is difficult that the nuclear transfer porcine embryos development to blastocyst stage overcoming the cell block in vitro. Abnormal segregation of chromosomes in nuclear transferred embryos on genome activation stage bring about embryo degeneration, abnormal blastocyst, delayed and low embryo development. Thus, we are evaluated that the correlations of the frequency of embryo developmental rates and chromosome aberration in NT and In viかo fertilization (IVF) derived embryo. We are used for ear-skin-fibroblast cell in NT. If only karyotyping of embryonic cells are chromosomally abnormal, they may difficultly remain undetected. Then, we evaluate the chromosome aberrations, fluorescent in situ hybridization (FISH) with porcine chromosome 1 submetacentric specific DNA probe were excuted. In normal diploid cell nucleus, two hybridization signal was detected. In contrast, abnormal cell figured one or three over signals. The developmental rates of NT and IVF embryos were 55% vs 63%, 32% vs 33% and 13% vs 17% in 2 cell, 8 cell and blastocyst, respectively. When looking at the types of chromosome aberration, the detection of aneuploidy at Day 3 on the embryo culture. The percentage of chromosome aneuploidy of NT and IVF at 4-cell stage 40.0%, 31.3%, respectively. This result indicate that chromosomal abnormalities are associated with low developmental rate in porcine NT embryo. It is also suggest that abnormal porcine embryos produced by NT associated with lower implantation rate, increase abortion rate and production of abnormal fetuses.