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Kim, Bang-Jin,Kim, Yong-Hee,Oh, Myeong-Geun,Kim, Ki-Jung,Jung, Sang-Eun,Jin, Ju-Hee,Kim, Sun-Uk,Min, Kwan-Sik,Ryu, Buom-Yong SCIENCE PRESS 2019 ASIAN JOURNAL OF ANDROLOGY Vol.21 No.2
<P>Spermatogonial stem cells (SSCs) transmit genetic information to the next progeny in males. Thus, SSCs are a potential target for germline modifications to generate transgenic animals. In this study, we report a technique for the generation of transgenic rats by <I>in vivo</I> manipulation of SSCs with a high success rate. SSCs in juvenile rats were transduced <I>in vivo</I> with high titers of lentivirus harboring enhanced green fluorescent protein and mated with wild-type females to create founder rats. These founder rats expressed the transgene and passed on the transgene with an overall success rate of 50.0%. Subsequent generations of progeny from the founder rats both expressed and passed on the transgene. Thus, direct modification of SSCs in juvenile rats is an effective means of generating transgenic rats through the male germline. This technology could be adapted to larger animals, in which existing methods for gene modification are inadequate or inapplicable, resulting in the generation of transgenic animals in a variety of species.</P>
Cryopreservation of putative pre-pubertal bovine spermatogonial stem cells by slow freezing
Kim, Ki-Jung,Lee, Yong-An,Kim, Bang-Jin,Kim, Yong-Hee,Kim, Byung-Gak,Kang, Hyun-Gu,Jung, Sang-Eun,Choi, Sun-Ho,Schmidt, Jonathan A.,Ryu, Buom-Yong Elsevier 2015 Cryobiology Vol.70 No.2
<P><B>Abstract</B></P> <P>Development of techniques for the preservation of mammalian spermatogonial stem cells (SSCs) is a critical step in commercial application of SSC based technologies, including species preservation, amplification of agriculturally valuable germ lines, and human fertility preservations. The objective of this study was to develop an efficient cryopreservation protocol for preservation of bovine SSCs using a slow freezing technique. To maximize the efficiency of SSC cryopreservation, the effects of various methods (tissue vs. cell freezing) and cryoprotective agents (trehalose, sucrose, and polyethylene glycol [PEG]) were tested. Following thawing, cells were enriched for undifferentiated spermatogonia by differential plating and evaluated for recovery rate, proliferation capacity, and apoptosis. Additionally, putative stem cell activity was assessed using SSC xenotransplantation. The recovery rate, and proliferation capacity of undifferentiated spermatogonia were significantly greater for germ cells frozen using tissue freezing methods compared to cell freezing methods. Cryopreservation in the presence of 200mM trehalose resulted in significantly greater recovery rate, proliferation capacity, and apoptosis of germ cells compared to control. Furthermore, cryopreservation using the tissue freezing method in the presence of 200mM trehalose resulted in the production of colonies of donor-derived germ cells after xenotransplantation into recipient mouse testes, indicating putative stem cell function. Collectively, these data indicate that cryopreservation using tissue freezing methods in the presence of 200mM trehalose is an efficient cryopreservation protocol for bovine SSCs.</P>
Kim, Bang-Jin,Lee, Yong-An,Kim, Ki-Jung,Kim, Yong-Hee,Jung, Mi-Seon,Ha, Seung-Jung,Kang, Hyun-Gu,Jung, Sang-Eun,Kim, Byung-Gak,Choi, Yu-Ri,Do, Jeong Tae,Ryu, Buom-Yong D.A. Spandidos 2015 International journal of molecular medicine Vol.36 No.1
<P>Spermatogonial stem cells (SSCs) are adult male germ cells that develop after birth. Throughout the lifetime of an organism, SSCs sustain spermatogenesis through self-renewal and produce daughter cells that differentiate into spermatozoa. Several studies have demonstrated that SSCs can acquire pluripotency under appropriate culture conditions, thus becoming multipotent germline stem cells (mGSCs) that express markers of pluripotency in culture and form teratomas following transplantation into immunodeficient mice. In the present study, we generated neural precursor cells expressing CD24, a neural precursor marker, from pluripotent stem cell lines and demonstrated that these cells effectively differentiated along a neural lineage in vitro. In addition, we found that paracrine factors promoted CD24 expression during the neural differentiation of mGSCs. Our results indicated that the expression of CD24, enhanced by a combination of retinoic acid (RA), noggin and fibroblast growth factor 8 (FGF8) under serum-free conditions promoted neural precursor differentiation. Using a simple cell sorting method, we were able to collect neural precursor cells with the potential to differentiate from mGSCs into mature neurons and astrocytes in vitro.</P>
정원줄기세포의 이종간 이식을 위한 효율적인 수여(Recipient) 생쥐 생산 기법 개발
김기중 ( Ki Jung Kim ),임한 ( Han Lim ),왕종현 ( Jong Hyun Wang ),김병각 ( Byung Gak Kim ),이용안 ( Yong An Lee ),김방진 ( Bang Jin Kim ),김용희 ( Yong Hee Kim ),홍영호 ( Yeong Ho Hong ),김근배 ( Geun Bae Kim ),류범용 ( Buom Yong 한국조직공학·재생의학회 2013 조직공학과 재생의학 Vol.10 No.1s
Spermatogonial xenotransplantation assay provides access to the several species germline and has been used in experimental animal models to study stem cell biology and germline development. To make the xenotransplantation technology more extensively accessible, it is require development of recipient preparation protocols. Therefore, we propose an optimal method for preparation of athymic nude recipient with busulfan treatment. To investigate the optimal concentration of busulfan treatment, athymic nude mice (6~8 weeks old) were intraperitoneally injected with different concentrations of busulfan (0, 15, 25, 35 and 45 mg/kg). 6~8 weeks after busulfan treatment, testicular weight was significantly lower in 45 mg/kg treated group than the other groups. And the percentage of spermatogenic tubule was significantly reduced in 45 mg/kg of busulfan treated recipient testis. Also we compared the gene expression level of sertoli-cell-derived growth factor, glial-cell-line-derived neurotrophic factor (GDNF) as a potential measure of niche function. Relative to the other experimental groups, 45 mg/kg busulfan treated recipient testis showed higher GDNF expression. Next, to find out the appropriate time to transplantation after treated with busulfan (45 mg/kg), the rat testicular donor cells were transplanted into recipient testis at 2, 4, 6 and 8 weeks after treated with busulfan. Analysis of recipient mice revealed that transplantation of donor cells on 6 weeks after busulfan treatment was the most effective time to support high level of donor stem cell engraftment. In this study, we provide an optimum experimental condition for preparation of recipient mouse model system for xenotransplantation. Also, our data could contribute to recipient preparation in other species.
Synthesis of Al_2O_3/SiC Composites by the SHS microwave Heating Process
Kim, Seuk-Buom 대한금속학회 2002 METALS AND MATERIALS International Vol.8 No.5
Alumina/silicon carbide composites were synthesized by the microwave induced SHS (Self-propagating Hightemperature Synthesis) process. Si02/Al/C powders were used as starting materials and samples were ignited by using a 2.45 ㎓ multimode home microwave oven (700W). Effects of the mixing ratio of SiO_2/Al/C powders, reaction environments, and weight percent of KNO_3 as a reaction promoter on the formation of the final product were studied.
Mbd2-CP2c loop drives adult-type globin gene expression and definitive erythropoiesis
Kim, Min ,Young,Kim, Ji ,Sook,Son, Seung ,Han,Lim, Chang ,Su,Eum, Hea ,Young,Ha, Dae ,Hyun,Park, Mi ,Ae,Baek, Eun ,Jung,Ryu, Buom-Yong,Kang, Ho ,Chul,Uversky, Vladi Oxford University Press 2018 Nucleic acids research Vol.46 No.10
<P><B>Abstract</B></P><P>During hematopoiesis, red blood cells originate from the hematopoietic stem cell reservoir. Although the regulation of erythropoiesis and globin expression has been intensively investigated, the underlining mechanisms are not fully understood, including the interplay between transcription factors and epigenetic factors. Here, we uncover that the Mbd2-free NuRD chromatin remodeling complex potentiates erythroid differentiation of proerythroblasts via managing functions of the CP2c complexes. We found that both Mbd2 and Mbd3 expression is downregulated during differentiation of MEL cells <I>in vitro</I> and in normal erythropoiesis in mouse bone marrow, and Mbd2 downregulation is crucial for erythropoiesis. In uninduced MEL cells, the Mbd2-NuRD complex is recruited to the promoter via Gata1/Fog1, and, via direct binding through p66α, it acts as a transcriptional inhibitor of the CP2c complexes, preventing their DNA binding and promoting degradation of the CP2c family proteins to suppress globin gene expression. Conversely, during erythropoiesis <I>in vitro</I> and <I>in vivo</I>, the Mbd2-free NuRD does not dissociate from the chromatin and acts as a transcriptional coactivator aiding the recruitment of the CP2c complexes to chromatin, and thereby leading to the induction of the active hemoglobin synthesis and erythroid differentiation. Our study highlights the regulation of erythroid differentiation by the Mbd2-CP2c loop.</P>
Kim,Seuk-Buom 경기대학교부설 산업기술종합연구소 1992 산업기술종합연구소 논문집 Vol.8 No.-
Tasi-Hill and Norris failure criteria were applied respectively to predict the strength of the tube-encased unidirectional glass fiber-epoxy composite rods under 3-D compressive stresses. Triaxial compressive stresses were applied by axially compressing longitudinally unidirectional E-glass fiber-epoxy matrix composite rods encased in thin-or thick-wall cylindrical steel thbes.
Kim,Seuk-Buom 경기대학교부설 산업기술종합연구소 1992 산업기술종합연구소 논문집 Vol.8 No.-
A New simple method was sought in a special case of three-dimensional stress analysis to get the elastic properties of angel-ply composite laminates compressed in the thickness direction, namely E₃, V₃₁and V₃₂, by applying Mohr's circle of stress and strain.