• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.125-131
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• 2000

Protoplasts of Arabidopsis thaliana were easily isolated from the shoot-forming (SF) suspension-cultured cell clusters with 4 hours-shaking condition (40 rpm) on CPD enzyme solution containing 1% cellulase R-10, 0.25% pectolyase Y-23 and 0.5% driselase. Protoplasts were cultured on liquid KAO medium supplemented with 1 mg/L 2,4-D, 0.5 mg/L kinetin, 200 mg/L spermidine and 68 g/L glucose. Also, protoplasts were cultured on 0.2 $\mu$M membrane filter placed onto CP solid medium containing the suspension cells as feeder cells in the dark at $25^{\circ}C$ for 4 weeks. Protoplast-derived-SF calli were cultured on MS medium containing 0.05 mg/L IAA, 7 mg/L 2 ip and 30 g/L sucrose under the continuous illumination for four weeks. The frequency of shoot formation was about 60%. The regenerants were transferred into potting soil to grow mature plants. The regenerants formed the silques with seeds after 8 weeks of cultures.

• Clinical and Experimental Reproductive Medicine
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• v.34 no.4
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• pp.219-227
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• 2007

• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.377-384
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• 2002

To investigate the expression patterns of proteins and growth factor signals in differentiated rabbit embryonic stem (ES) cells, ES cells with confluent stage grown of feeder layer and differentiated cells into embryoid bodies (EB) without feeder cell were applied to protein gel and Western blotting analysis. There were 66kDa and 28kDa specifically expressed in differentiated ES cell but not in undifferentiated ES cell while 25kDa protein band showed up in only undifferentiated ES cells. Also there were some difference of protein bands in several area of gel between differentiated and undifferentiated ES cells such as about 100 kDa, 50kDa and 27kDa areas, but there was no difference in band pattern of one-dimensional gel analysis between mouse ES cells and rabbit ES cells. IGF-I receptor and EGF receptor were expressed in differentiated cells and undifferentiated cells. And ICF-I and EGF were not expressed in both differentiated and undifferentiated cells. These results indicated that ES cells express their own proteins to inhibit differentiation while EB cells synthesize different proteins to differentiate, and 16F-I receptor and EGF receptor were expressed in both ES and EB cells probably for the different functions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.615-625
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• 1997

An efficient protocol for plant regeneration from protoplasts of the indica rice variety IR43 has been developed. The procedure involved plating of embryogenic suspension-derived protoplasts on the surface of a filter membrane overlaying agarose-embedded feeder cells. Lolium multiflorum cell suspensions were preferable to these of Oryza ridleyi as feeder cells and Lolium suspensions supported colony formation from up to 0.68％ of the protoplasts, depending on the age of cell suspensions. Plant regeneration frequency was significantly improved by using maltose alone or in a 1:1(w/w) combination with sucrose as carbohydrate source and a simple dehydration treatment using a high concentration of agarose in the regeneration medium. Medium containing maltose or maltose mixed with sucrose increased the plant regeneration frequency compared with medium containing sucrose alone. The plant regeneration frequency was increased to 30.7 to 70.7％ following dehydration treatment, while the non-treated controls showed a regeneration frequency of 3.1 to 30.6％. Protoplast-derived plants were transferred to the glasshouse, flowered with morphologically normal.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.4
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• pp.265-272
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• 2006

Objective: This study was carried out to evaluate the effect of the isolation methods of inner cell mass from mouse blastocyst, types of feeder cells and treatment time of mitomycin C on the formation rate of ICM colony. Methods: The inner cells were isolated by conventional immunosurgery, partial trophoblast dissection with syringe needles and whole blastocyst co-culture method. Commercially available STO and primary cultured mouse embryonic fibroblast (pMEF) feeder cells were used, and mitomycin C was treated for 1, 2 or 3 hours, respectively. The formation rate of ICM colony was observed after isolation of ICM and culture of ICM on the feeder cells for 7 days. Result: The ICM colony formation rate on STO were significantly higher in partial trophoblast dissection group (58%) than that in immunosurgery (12%) or whole blastocyst culture (16%) group (p<0.05). The formation rate on pMEF feeder layer was higher in partial trophoblast dissection (88%) and whole blastocyst culture (82%) group than that in immunosurgery (16%) group (p<0.05). When mitomycin C treated to pMEF for 2 hours, the formation rate of 88% was significantly higher than those of other conditions. Conclusion: Above results showed that the efficient isolation method of ICM from blastocyst was the partial trophoblast dissection and the appropriate treatment time of mitomycin C was 2 hours. However, the subculture of ICM colony and characterization of stem cells should be carried out to confirm the efficacy of the partial trophoblast dissection method.

• Reproductive and Developmental Biology
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• v.34 no.1
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• pp.1-6
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• 2010

Mesenchymal stem cells (MSCs) have the multipotent capacity and this potential can be applied for obtaining valuable cell types which can use for cell therapy on various regenerative diseases. However, insufficient availability of cellular source is the major problem in cell therapy field using adult stem cell sources. Recently, human embryonic stem cells (hESCs) have been highlighted to overcome a limitation of adult cellular sources because they retain unlimited proliferation capacity and pluripotency. To use of hESCs in cell therapy, above all, animal pathogen free culture system and purification of a specific target cell population to avoid teratoma formation are required. In this study, we describe the differentiation of a mesenchymal stem cell-like cells population from feeder-free cultured hESCs(hESC-MSCs) using direct induction system. hESC-MSCs revealed characteristics similar to MSCs derived from bone marrow, and undifferentiated cell markers were extremely low in hESC-MSCs in RT-PCR, immunostaining and FACS analyses. Thus, this study proffer a basis of effective generation of specialized human mesenchymal stem cell types which can use for further clinical applications, from xenofree cultured hESCs using direct induction system.

• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.219-225
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• 2001

To establish rabbit Embryonic Stem (ES) cells, rabbit one-cell embryos were collected and cultured in vitro to blastocysts. Blastocysts were co-cultured with mouse embryonic fibroblasts (MEF), rabbit embryonic fibroblasts (REF) or 570 cells expressing LIF (SNL). Although rabbit ES cells were isolated with low efficiencies, total 8 ES cell lines were kept in vitro with normal colony shape. The MEF was the best feeder for rabbit ES cell isolation in regard to growth rate and undifferentiated morphology. The doubling time of rabbit ES cells in MEF was about 84 hours and the undifferentiated morphology was maintained following passing and freezing processes. These rabbit ES cells were differentiated into embryoid body following the culture in the uncoated dishes, indicating that they were undifferentiated stem cells.

• Journal of Life Science
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• v.10 no.1
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• pp.37-44
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• 2000

The mammary gland contains a subpopulation of epithelial cells with large proliferative potentials which are the likely targets for carcinogens. These clonogenic cells can proliferate and differentiate into functional glandular structures. Rat mammary epithelial cells (RMEC) were isolated and characterized in vitro. By flow cytometry of RMEC stained with fluorescein isothiocyanate-peanut agglutinin(PNA) and phycoerythrin anti-Thy-1.1 monoclonal antibody, it was possible to four cell subpopulations from 7-8 week old F344 female rat mammary glands: cells negative to both reagents (B-), PNA-positive cells (PNA+), Thy-1.1-positive cells (Thy-1.1+), and cells positive to both reagents (B+). When single PNA+ cells were isolated and cultured in Matrigel with irradiated (∼50 Gray) 3T3 fibroblast feeder layer, they gave rise to multicellular clonal structures of three types: alveolar, foamy alveolar, and squamous colonies. The developed structures were similar to the mammary glands in vivo. These results suggest that some of PNA+ cells possesses many of the characteristics of multipotent clonogenic stem-like cells.

• Journal of Embryo Transfer
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• v.27 no.3
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• pp.189-192
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• 2012

Although embryonic stem cells (ESCs) or ES-like cells are reported from many mammalian species other than the mouse, the culture system for murine ESCs may not be suitable to the other species. Previously many other research groups have modified either human or mouse ESC culture systems for bovine ESC culture. In this study, we compared three different culture mediums consisting of DMEM, ${\alpha}$-MEM or KnockOut$^{TM}$-DMEM (KO), which are modified from human or mouse ESC culture system, for the generation of bovine ESCs. In this study, some pre-requisite events which are important for establishment and long-term propagation of ESCs such as inner cell mass (ICM) attachment on feeder cells, primary colony formation and sustainability after passaging. Once the ICM clumps attached on feeder cells, this was designated as passage 0. In regards to the rate of ICM attachment, ${\alpha}$-MEM was superior to the other systems. For primary colony formation, there was no difference between DMEM and ${\alpha}$-MEM whereas KO showed lower formation rate than the other groups. For passaging, the colonies were split into 2~4 pieces and passed every 5~6 days. From passage 1 to passage 3, DMEM system seemed to be appropriate for maintaining putative bovine ESCs. On the other hand, ${\alpha}$-MEM tended to be more suitable after passage 6. Although ${\alpha}$-MEM support to maintain a ES-like cell progenies to passage 15, all three culture systems which are modified from human or mouse ESC culture media failed to retain the propagation and long-term culture of putative bovine ESCs. Our findings imply that more optimized alternative culture system is required for establishing bovine ESC lines.

• Development and Reproduction
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• v.6 no.1
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• pp.55-66
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• 2002

Embryonic stem cells(ES cells) are derived from the inner cell mass(ICM) of blastocysts, which have the potentials to remain undifferentiated, to proliferate indefinitely in vitro, to differentiate into the derivates of three embryonic germ layers. ES cells are an attractive model system for studying the initial developmental decisions and their molecular mechanisms during embryogenesis. Additionally, ES cells of significant interest to those characterizing the various gene functions utilizing transgenic and gene targeting techniques. We investigated the effects of reproductive hormones, gonadotropins(GTH) and steroids on the induction of differentiation and expressions of their receptor genes using the newly established mouse ES cells. We collected the matured blastocysts of inbred mice C57BL/6J after superovulation and co-cultured with mitotically inactivated STO feeder cells. After 5 passages, we confirmed the expression alkaline phosphatase(Alk P) activity and SSEA-1, 3, 4 expressions. The protocol devised for inducing ES differentiation consisted of an aggregation steps, after 5 days as EBs in hormone treatments(FSH, LH, E$_2$, P$_4$, T) that allows complex signaling to occur between the cells and a dissociation step, induced differentiation through attachment culture during 7 days in hormone treatments. Hormone receptors were not increased in dose-dependent manner. All hormone receptors in ES cells treated reproductive hormones were expressed lower than those of undifferentiated ES cell except for LHR expression in E$_2$-treated ES cells group. After hormone induced differentiation, at least some of the cells are not terminally differentiated, as is evident from the expression of Oct-4, a marker of undifferentiated. To assess their differentiation by gene expression, we analyzed the expression of 7 tissue-specific markers from all three germ layers. Most of hormone-treated group increased in the expression of gata-4 and $\alpha$ -fetoprotein, suggesting reproductive hormone allowed or induced differentiation of endoderm.