• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.168-173
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• 2004

The ability of frozen-thawed fetal skin was examined to generate viable cell lines for nuclear transfer. Fetal skin frozen at -20$-20^{\circ}C$, $-30^{\circ}C$ or $-80^{\circ}C$ in the presence of 5% DMSO used as tissue explants to generate somatic cells. The resultant confluent cells were then used as donors for nuclear transfer (NT). Of the bovine NT embryos reconstracted from the somatic cells, 62.3%, 76.6% to 65% showed cleavage 70.5%, 81.9% to 78.5% reached the stage of morula formation and 39.7%, 43.2% or 47.6% reached the blastocyst stage. There was no significant difference in development when the NT embryos were compared with those reconstracted from fresh somatic cell derieved skin tissues (72%, 75.3%, and 45.2%, for cleavage, and development to morula and blastocyst stage, respectively). NT embryos were then placed in a portable $CO_2$ incubator and carried to China from Japan by air. After reaching to farm, two NT embryos were transferred to each of 5 recipients. We obtained 2 NT calves which birth weights is 30kg and 36kg female, and gestation periods is 281 and 284 days, respectively. There were no observation any abnormality from those calves. The results indicated that cell lines derieved from bovine fetal skin cryopreserved by a simple method could be used as donors in nuclear transfer using the portable $CO_2$ incubator.

• Korean Journal of Medicinal Crop Science
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• v.13 no.1
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• pp.57-62
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• 2005

Salt-tolerant transgenic Panax ginseng plants were produced by introducing the SAL1 geue (3'(2'), 5'-bis-phosphate nucleotidase) that confers tolerance to the salts through Agrobacterium tumefaciens co-cultivation. Cotyledon explants of immature ginseng zygotic embryos cultured on Murashige and Skoog medium lacking growth regulators formed somatic embryos directly with below 10%, but the 74% tranformation rate were observed at the treatment of phytohormone with 1.0 mg/l 2,4-D and 0.5 mg/l kinetin. Somatic embryos were initially cultured on MS medium supplemented with 250 mg/l cefotaxime for 3 weeks and subsequently subcultured five times to a medium containing 100 mg/l kanamycin and 250 mg/l cefotaxime. Upon development into the cotyledonary stage, these somatic embryos were transferred to on the medium containing 50 mg/l kanamycin and 10 mg/l gibberellic acid to induce germination and strong selection. Integration of the transgene into the plants was confirmed by polymerase chain reaction with specific primers. The ginseng transformants with well-developed shoots and roots were successfully acclimatized in a greenhouse when they were planted in soil.

• Current Research on Agriculture and Life Sciences
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• v.16
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• pp.31-36
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• 1998

In order to investigate the effect of cytokinins on the cotyledonary variability of somatic embryos in Heracleum moellendorffii Hance., somatic embryos were induced from the immature zygotic embryo on MS medium containing 1.0mg/l 2, 4-D, and then transferred to 2,4-D-free and cytokinin-added medium for somatic embryogenesis after 4weeks culture. Polycotyledonary embryos were formed most abundantly(84.9%) on the 0.2mg/l BA medium as compared with the 0.2mg/l 2ip(42.6%) and kinetin(32.9%) media, and it was proportional to BA concentrations(0.01~0.1mg/l). The rate of polycotyledonary embryo formation increased proportional to the period of BA treatment and also increased more at the globular stage than at the heart, torpedo-shaped and cotyledonary stages.

• Journal of Embryo Transfer
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• v.27 no.3
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• pp.149-154
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• 2012

This study was carried out to investigate effective condition for producing somatic cell nuclear transfer (SCNT) embryos of Jeju native cattle. As donor cells for SCNT, ear skin cells from Jeju native cattle were used. In experiment 1, the effect of recipient oocyte sources on the development of Jeju native cattle SCNT embryos were examined. Fusion rate of recipient oocyte and donor cell was not different between the Hanwoo and Holstein recipient oocytes (86.0% vs 89.9%). The rate of embryos developing to the blastocyst stage was significantly (p<0.05) higher in Hanwoo recipient oocytes than in Holstein recipient ones (28.2% vs 14.7%). Blastocysts derived from Hanwoo recipient oocytes contained higher numbers of total cells than those derived from Holstein ones ($115.1{\pm}40.8$ vs $101.4{\pm}33.3$), although there were no significant difference. The mean proportion of apoptotic cells in blastocyst was not different between the sources of recipient oocytes. In experiment 2, the development of Jeju native cattle and Hanwoo SCNT embryos were compared. Hanwoo oocytes were used as the recipient oocytes. Fusion rate was not different between the Jeju native cattle and Hanwoo SCNT embryos (92.1% vs 92.9%). The blastocyst rate of SCNT embryos was significantly (p<0.05) lower in Jeju native cattle than in Hanwoo (16.9% vs 31.0%). Blastocysts derived from Jeju native cattle SCNT embryos contained smaller numbers of total cells than those derived from Hanwoo ones ($136.6{\pm}33.7$ vs $149.9{\pm}39.7$), but there were no significant difference. The mean proportion of apoptotic cells in blastocyst was not different between the Jeju native cattle and Hanwoo SCNT embryos. The present study demonstrated that Hanwoo recipient oocytes were more effective in supporting production of Jeju native cattle SCNT embryos, although Jeju native cattle SCNT embryos showed reduced developmental capacity when compared to Hanwoo SCNT embryos.

• Korean Journal of Medicinal Crop Science
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• v.10 no.1
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• pp.41-45
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• 2002

An efficient and reproducible procedure for the large scale propagation of Hovenia dulcis Thunb. is described. Shoot primodia emerging from the leaf surface was induced from MS medium supplemented with NAA. Stem cuttings were suitable explants for multiple shoot proliferation. They produced axillary shoots which branched repeatedly, yielding an average of 7 shoots per explants after 4 weeks in culture, when cultured on a woody plant medium (WPM) containing 0.1mg/l BA and 0.1mg/l NAA. Stem, leaf and root segments from axenic seedlings were used as explant source to induce somatic embryogenesis. A high frequency of somatic embryos were induced directly from leaf in MS medium with NAA, 2,4-D and in medium containing NAA, 2,4-D with BA. Somatic embryos were germinated in MS medium supplemented with 1mg/ l $GA_3$. Somatic embryos proliferated secondary somatic embryos rapidly after transfer to MS medium supplemented with 1mg/ l kinetin, 1mg/ l $GA_3$ and 2% dextrose.

• Journal of Embryo Transfer
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• v.17 no.2
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• pp.109-115
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• 2002

The present study was conducted for the production of transgenic cloned cows those secrete human lactoferricin into milk by somatic cell nuclear transfer (NT). To estimate detrimental effects of gene transfection on transgenic cloned embryo production, development rates of NT embryos were compared between transfected and non-transfected cumulus and ear fibroblast cells. An expression plasmid for human lactofericin (pbeta-LFC) was constructed by inserting a bovine beta-casein promoter, a green fluorescent protein (GFP) marker gene, and human lactoferricin target gene into a pcDNA3 plasmid. Two bovine somatic cell lines (cumulus cell and ear fibroblast) were established and transfected with the expression plasmid using a liposomal transfection reagent, Fugene6 as a carrier. Cumulus cell and ear fibroblast were transfected at the passage of 2 to 4, trypsinized and GFP-expressing cells were randomly selected and used for somatic cell NT. Developmental competences (rates of fusion, cleavage, and blastocyst formation) in bovine transgenic somatic cell NT embryos reconstructed with non-transfectecd cells were significantly higher than those from transfected cells in cumulus cell and ear fibroblast (P＜0.05). This study indicated that transfection of done. cell has detrimental effect on embryo development in bovine transgenic NT.

• Journal of Korean Society of Forest Science
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• v.97 no.1
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• pp.127-133
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• 2008

This study was conducted to establish the optimal condition for plant regeneration and acclimatization from somatic embryos of Panax ginseng. Cotyledon segments of Panax ginseng produced primary and secondary somatic embryos when cultured on MS and WPM media supplemented with 7% sucrose. To induce plantlet conversion, cotyledonary somatic embryos were cultured on WPM solid medium with $GA_3$ at various concentrations (1~30 mg/L) for 4 weeks. Plantlets were transferred to 1/2 WPM solid medium with $GA_3$ at various concentrations (0~5 mg/L) and 0.5% activated charcoal for shoot and root elongations. Elongated plantlets further developed into well-developed leaf and root system on 1/3 SH medium with 0.5% activated charcoal under ventilation condition for 5 months. The highest survival rate to soil was 75% when plantlets were regenerated on 1/3 SH medium without sucrose under ventilation condition.

• Journal of Embryo Transfer
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• v.23 no.2
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• pp.67-76
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• 2008

Since the birth of Dolly using fully differentiated somatic cells as a nuclear donor, viable clones were generated successfully in many mammalian species. These achievements in animal cloning demonstrate developmental potential of terminally differentiated somatic cells. At the same time, the somatic cell nuclear transfer (SCNT) technique provides the opportunities to study basic and applied biosciences. However, the efficiency generating viable offsprings by SCNT remains extremely low. There are several explanations why cloned embryos cannot fully develop into viable animals and what factors affect developmental potency of reconstructed embryos by the SCNT technique. The most critical and persuasive explanation for inefficiency in SCNT cloning is incomplete genomic reprogramming, such as DNA methylation and histone modification. Numerous studies on genomic reprogramming demonstrated that incorrect DNA methylation and aberrant epigenetic reprogramming are considerably correlated with abnormal development of SCNT cloned embryos even though its mechanism is not fully understood. The SCNT technique is useful in cloning farm animals because pluripotent stem cells are not established in farm animal species. Therapeutic cloning combined with genetic manipulation will help to control various human diseases. Also, the SCNT technique provides a chance to overcome excessive demand for the organs by production of transgenic animals as xenotransplantation resources. Here, we describe the factors affecting the efficiency of generating cloned farm animals by the SCNT technique and discuss future directions of animal cloning by SCNT to improve the cloning efficiency.

• Journal of Plant Biotechnology
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• v.31 no.2
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• pp.121-126
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• 2004

Bleeding heart (Dicentra spectabilis L. Lemaire) is one of the most valuable wild flower in Korea. This work was conducted for the mass production of somatic embryos through suspension culture and more effective plant regeneration system in Dicentra spectabilis. High-frequency embryogenic callus proliferation was achieved in SH liquid medium supplemented with 1 mg/L 2,4-D. Half-strength SH medium was suitable concentration for somatic embryo induction and germination. About 5,000 embryos were produced per 250$m\ell$ flask after 4 weeks of culture. Germination rate of somatic embryos was decreased when GA$_3$ was added in medium. The plantlets showed a 58％ survival rate when transferred to pots after 1 month of culture. The results indicate that micropropagation procedure via somatic embryogenesis can be applied for an efficient mass propagation of Dicentra spectabilis.

• Journal of Ginseng Research
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• v.23 no.4
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• pp.199-204
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• 1999

Cotyledon explants of Korean ginseng (Panax ginseng C.A. Meyer), a perennial medicinal plant, produced direct somatic embryos at a high frequency on MS medium without growth regulators. Cytokinin highly suppressed the somatic embryogenesis but stimulated direct fomlation of adventitious buds. BAP was more effective than kinetin for the formation of adventitious bud. IBA combination with cytokinin enhanced the frequency of adventitious bud formation. The highest frequency of adventitious bud formation were $40\%$ at 0.05 mg/l IBA and 5 mg/l BAP. Adventitious buds were mainly formed near the distal portion of cotyledon, while somatic embryos were only formed near the proximal portion of cotyledon. Adventitious buds were covered with sheath similar to axillary buds in the zygotic embryos, and then leaf-like epicotyls were developed.