• Journal of Life Science
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• v.25 no.11
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• pp.1230-1234
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• 2015

GATA binding protein 6 (GATA6) is a transcription factor that is expressed in the early blastocyst stage and controls the expression of important genes in the differentiation and development of the heart, pancreas, and intestine. This study confirmed the role of GATA6 in cell differentiation and organ development using mouse embryonic stem cells and zebrafish, respectively. First, the mouse embryonic stem cells were differentiated into pacemaker cardiomyocytes. An RT-PCR analysis revealed that the expression of the GATA6 gene was greatly increased from day 4 of differentiation. The expression of GATA6 was upregulated prior to increased expression of NK2 homeobox 5 (Nkx2.5) and myocyte enhancer factor 2C (MEF2C), which are critical transcription factors involved in regulating heart formation. To examine the role of GATA6 in development, GATA6 morpholino was microinjected into zebrafish embryos. Knockdown of GATA6 expression significantly decreased the heart size and heart rate in the zebrafish compared to a control. In addition, the brains were degenerated in the GATA6 morpholino-injected zebrafish. Acridine orange staining showed that knockdown of GATA6 expression increased apoptotic cells in the brain. Interestingly, knockdown of GATA6 expression decreased apoptotic cells in the early bud stage. This study points to the importance of the GATA6 gene in heart and brain development.

• Journal of Embryo Transfer
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• v.10 no.1
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• pp.53-63
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• 1995

The effects of different protein sources (serum vs bovine serum albumin), growth factors (EGF and PDGF) and co-culture with various type of somatic cel1s (BOEC, MEF and BRL) on the in vitro development of in vitro matured / in vitro fertilized bovine oocytes were examined, and the viability of frozen/thawed embryos derived from IVM /IVF was examined. Cell numbers of blastocysts were also counted. In Experiment 1, CR$_1$aa with serum was superior to CR$_1$aa with BSA in producing morulae plus blastocysts from IVM /IVF oocytes(24.4% vs 30.4%, p>0.05). In Experiment 2, more morulae plus blastocysts(42.3%) were produced in CR$_1$aa containing long /ml EGF than in the control CR$_1$aa(33.3%). In Experiment 3, 2- to 8-cell embryos derived from IVM /IVF oocytes were randomly allotted to one of 4 culture groups : a) CR$_1$aa ; b) CR$_1$aa + ing /ml PDGF ; CR$_1$aa + Sng /ml PDGF ; CR$_1$aa + lOng /ml PDGF ; culture resulted in 21.3, 51.2, 41.4 and 45.9%(p<0.05), respectively, developing into morulae and blastocysts. In Experiment 4, 0 and Sng /ml PDGF added to CR$_1$aa coculture with BRL or BOEC yielded 47.5, 42.5, 33.8 and 41.6% morulae and blastocysts, respectively. In Experiment 5, the proportion of embryos into morulae and blastocysts was highest in CR$_1$aa with MEF coculture group(50.9%) compared to any other group(CR$_1$aa, 22.3%; CR$_1$aa+BRL, 32.9%; CR$_1$aa+BOEC, 33.8%, p>0.05). In Experiment 6, survival rate of blastocysts produced by in vitro fertilization when cryoprotectant was removed in 0.7M glycerol+0.7M sucrose and 0.7M sucrose solution for 10 min. after thawing at 2$0^{\circ}C$ (Exp. H, 58.8%) was slightly higher than when cryoprotectant was removed 10%, 6.7% and 3.3% glycerol for 10 min. after thawing at 37$^{\circ}C$ (Exp. I, 54.3%). These study indicate that growth factors and somatic cell co-culture can increase the proportion of embryos that develop into morulae and blastocysts without an increase in the cell number and frozen /thawed method employed this experiment was not different.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.148-151
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• 2010

The aim of this study was to investigate the erythromycin resistance patterns of Enterococci sp. present in cow milk. A total 110 erythromycin resistant Enterococci were isolated from milk samples; E. faecalis (n=101), E. avium (n=7), and E. durans (n=2). The minimum inhibitory concentration of erythromycin against 110 Enterococci were determined. The 66.3% of Entercocci (n=73) showed high level resistance (${\geq}64$ mg/ml). Among 110 isolates, 86.3% (n=95) showed $cMLS_B$ phenotype and 13.6% (n=15) showed $iMLS_B$ The aim of this study was to investigate the erythromycin resistance patterns of Enterococci sp. present in cow milk. A total 110 erythromycin resistant Enterococci were isolated from milk samples; E. faecalis (n=101), E. avium (n=7), and E. durans (n=2). The minimum inhibitory concentration of erythromycin against 110 Enterococci were determined. The 66.3% of Entercocci (n=73) showed high level resistance (${\geq}64$ mg/ml). Among 110 isolates, 86.3% (n=95) showed $cMLS_B$ phenotype and 13.6% (n=15) showed $iMLS_B$ phenotype. All of isolates have erm(B) determinant, 75.45% (n=83) have mef(A) an efflux system determinant. The majority of Enetrcococci isolated from raw milk samples in northern area of Gyeonggi-Do showed high level of resistance to erythromycin.

• YAKHAK HOEJI
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• v.52 no.1
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• pp.67-72
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• 2008

The use of doxorubicin, which is one of the most effective anticancer agents, is often limited by occurrence of acquired resistance in tumor cells. GSH has been shown to be involved in the development of this drug resistance. Transcription factor Nrf2 governs the expression of GSH synthesizing glutamylcysteine ligase (GCL), as well as multiple phase 2 detoxifying enzymes. Here we show that Nrf2 is one of factors determining doxorubicin sensitivity. Nrf2-deficient fibroblasts (murine embryonic fibroblasts, MEF) were more susceptible to doxorubicin mediated cell death than wild-type cells. Doxorubicin treatment elevated levels of Nrf2-regulated genes including NAD(P)H: quinone oxidoreductase (Nqo1) and GCL in wild-type fibroblasts, while no induction was observed in Nrf2-deficient cells. Doxorubicin resistance in human ovarian SK-OV cells was reversed by treatment with L-buthionine-sulfoxamine (BSO), which is depleting intracellular GSH. Finally, transfection of SK-OV cells with Nrf2 siRNA resulted in exacerbated cytotoxicity following doxorubicin treatment compared to scrambled RNA control. These results indicate that the Nrf2 pathway, which plays a protective role in normal cells, can be a potential target to control cancer cell resistance to anticancer agents.

• Molecules and Cells
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• v.40 no.9
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• pp.667-676
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• 2017

Abnormal differentiation of muscle is closely associated with aging (sarcopenia) and diseases such as cancer and type II diabetes. Thus, understanding the mechanisms that regulate muscle differentiation will be useful in the treatment and prevention of these conditions. Protein lysine acetylation and methylation are major post-translational modification mechanisms that regulate key cellular processes. In this study, to elucidate the relationship between myogenic differentiation and protein lysine acetylation/methylation, we performed a PCR array of enzymes related to protein lysine acetylation/methylation during C2C12 myoblast differentiation. Our results indicated that the expression pattern of HDAC11 was substantially increased during myoblast differentiation. Furthermore, ectopic expression of HDAC11 completely inhibited myoblast differentiation, concomitant with reduced expression of key myogenic transcription factors. However, the catalytically inactive mutant of HDAC11 (H142/143A) did not impede myoblast differentiation. In addition, wild-type HDAC11, but not the inactive HDAC11 mutant, suppressed MyoD-induced promoter activities of MEF2C and MYOG (Myogenin), and reduced histone acetylation near the E-boxes, the MyoD binding site, of the MEF2C and MYOG promoters. Collectively, our results indicate that HDAC11 would suppress myoblast differentiation via regulation of MyoD-dependent transcription. These findings suggest that HDAC11 is a novel critical target for controlling myoblast differentiation.

• BMB Reports
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• v.40 no.4
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• pp.547-553
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• 2007

Many motifs along the 1.2 kb myostatin promoter (MSTNpro) in sheep have been found by the MatInspecter program in our recent study. To further verify the role of the motifs and better understand the transcriptional regulation mechanism of the myostatin gene in sheep, the reporter gene EGFP (enhanced green fluorescent protein) was selected and the wild-type (W) vector MSTNPro$^W$-EGFP or motif-mutational (M) vector MSTNPro$^M$-EGFP were constructed. The transcriptional regulation activities were analyzed by detecting the fluorescence strength of EGFP in C2C12 myoblasts transfected with the vectors. The results showed that E-box (E) 3, E4, E5 and E7, particularly E3, E5 and E7, had important effects on the activity of the 1.2 kb sheep myostatin promoter. In addition, we also detected several other important motifs such as MTBF (muscle-specific Mt binding factor), MEF2 (myocyte enhancer factor 2), GRE (glucocorticoid response elements) and PRE (progesterone response elements) along the sheep myostatin promoter by the mutational analysis.

• Biomolecules & Therapeutics
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• v.19 no.4
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• pp.451-459
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• 2011

Peroxiredoxins (Prxs) have a critical role in protecting cells against oxidative damage generated by reactive oxygen species (ROS). PrxI and PrxII are more than 90% homologous in their amino acid sequences, and both proteins reduce $H_2O_2$. In this study, an over-expression plasmid carrying PrxI was transfected into $PrxII^{-/-}$ mouse embryonic fibroblasts (MEFs) to investigate potential compensatory relationships between PrxI and PrxII. ROS levels induced by oxidative stress were increased in $PrxII^{-/-}$ MEFs as compared to wild-type MEFs. Moreover, exposure of $PrxII^{-/-}$ MEFs to $H_2O_2$ caused a reduction in cell viability of about 10%, and the proportion of cell death was increased compared to mock-treated $PrxII^{-/-}$ MEFs. However, transient over-expression of PrxI in $PrxII^{-/-}$ MEFs conferred increased resistance against the oxidative damage, as evidenced by increased cell viability and reduced intracellular ROS levels under $H_2O_2$ stress conditions. The findings suggest that over-expressed PrxI can partly compensate for the loss of PrxII function in PrxII-deficient MEFs.

• Journal of Chest Surgery
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• v.18 no.3
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• pp.517-528
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• 1985

Pulmonary function studies today are generally accepted as an integral part of the evaluation of poor-risk patients who are to have pulmonary surgery. The effect of various pulmonary surgery on lung function was investigated in 54 patients in whom comprehensive lung function test were performed before and between 2 months and 14 months after operation at the Department of Thoracic Surgery, Seoul National University Hospital. According to the result of analysis, the effect of pulmonary resection on forced flow rate was keeping with the change of lung volume, and the preoperative level of ventilatory function plays a major role in determining postoperative loss of functioning lung. Although all measures of expiratory flow [FVC, FEV1, FEFO.2-1.2, MEF50, FEF25-75] have the same percentage of reproducibility, but FEV1 shows most sensitive, reliable linear correlation with the functioning pulmonary tissue loss than other parameters. The linear regression lines derived from the correlation between preoperative [X] and postoperative [Y] FEV1 on various surgical procedures were as follows: 1. Y = 0.57X 0.03. in pneumonectomy group of lung cancer[r=0.84]. 2. Y = 0.56X + 0.33. in lobectomy group of lung cancer[r=0.79]. 3. Y = 0.69X + 0.25. in lobectomy group of pulmonary infection[r=0.91].

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.40.2-40.2
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• 2018

외계행성 탐색시스템으로 관측한 영상은 한국천문연구원 본원에 있는 자료처리 시스템으로 실시간 전송된다. 이를 위해 한국과학기술정보연구원이 운영 중인 첨단망과 UDP 전송 프로그램을 활용하고 있으며 연간 약 140TB의 관측 영상을 칠레 55Mbps, 남아공 39Mbps, 호주 410Mbps의 속도로 전송하고 있다. 관측 영상이 전송되면 MEF 포맷으로 구조화 하고 bias, flat, crosstalk 보정과 bad pixel masking 등의 전처리 과정을 거쳐 각 연구과제별로 실시간 배포하고 있다. 중력렌즈 연구를 위한 우리 은하 중심부 관측영상은 차감영상 기법을 사용하여 약 3억 개의 별에 대해 측광하고 있으며, $18K{\times}18K$ 크기의 대용량 관측 영상을 빠르고 효율적으로 처리하기 위해 256개로 분할하여 분산처리하고 있다. 2014년부터 자료처리를 위한 시스템을 구축하고 증설하였으며 현재 11대의 서버(212Core)와 2.7PB의 NAS 스토리지를 운영하며 연간 700TB이상의 자료를 처리하고 있다. 우리은하 중심부 측광자료에서 검출된 변광 현상을 정리하여 측광데이터베이스를 구축하였다. 본 발표에서는 KMTNet 실시간 자료처리 과정에 대한 상세한 내용과 향후 자료처리 시스템 개선방향에 대해 소개한다.

• Molecules and Cells
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• v.42 no.2
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• pp.175-182
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• 2019

microRNAs regulate a diverse spectrum of cancer biology, including tumorigenesis, metastasis, stemness, and drug resistance. To investigate miRNA-mediated regulation of drug resistance, we characterized the resistant cell lines to 5-fluorouracil by inducing stable expression of miRNAs using lenti-miRNA library. Here, we demonstrate miR-551a as a novel factor regulating cell survival after 5-FU treatment. miR-551a-expressing cells (Hep3B-lenti-miR-551a) were resistant to 5-FU-induced cell death, and after 5-FU treatment, and showed significant increases in cell viability, cell survival, and sphere formation. It was further shown that myocyte-specific factor 2C is the direct target of miR-551a. Our results suggest that miR-551a plays a novel function in regulating 5-FU-induced cell death, and targeting miR-551a might be helpful to sensitize cells to anti-cancer drugs.