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p31comet Induces cellular senescence through p21 accumulation and Mad2 disruption.
Yun, Miyong,Han, Young-Hoon,Yoon, Sun Hee,Kim, Hee Young,Kim, Bu-Yeo,Ju, Yeun-Jin,Kang, Chang-Mo,Jang, Su Hwa,Chung, Hee-Yong,Lee, Su-Jae,Cho, Myung-Haing,Yoon, Gyesoon,Park, Gil Hong,Kim, Sang Hoon,L American Association for Cancer Research 2009 Molecular Cancer Research Vol.7 No.3
<P>Functional suppression of spindle checkpoint protein activity results in apoptotic cell death arising from mitotic failure, including defective spindle formation, chromosome missegregation, and premature mitotic exit. The recently identified p31(comet) protein acts as a spindle checkpoint silencer via communication with the transient Mad2 complex. In the present study, we found that p31(comet) overexpression led to two distinct phenotypic changes, cellular apoptosis and senescence. Because of a paucity of direct molecular link of spindle checkpoint to cellular senescence, however, the present report focuses on the relationship between abnormal spindle checkpoint formation and p31(comet)-induced senescence by using susceptible tumor cell lines. p31(comet)-induced senescence was accompanied by mitotic catastrophe with massive nuclear and chromosomal abnormalities. The progression of the senescence was completely inhibited by the depletion of p21(Waf1/Cip1) and partly inhibited by the depletion of the tumor suppressor protein p53. Notably, p21(Waf1/Cip1) depletion caused a dramatic phenotypic conversion of p31(comet)-induced senescence into cell death through mitotic catastrophe, indicating that p21(Waf1/Cip1) is a major mediator of p31(comet)-induced cellular senescence. In contrast to wild-type p31(comet), overexpression of a p31 mutant lacking the Mad2 binding region did not cause senescence. Moreover, depletion of Mad2 by small interfering RNA induced senescence. Here, we show that p31(comet) induces tumor cell senescence by mediating p21(Waf1/Cip1) accumulation and Mad2 disruption and that these effects are dependent on a direct interaction of p31(comet) with Mad2. Our results could be used to control tumor growth.</P>
Enhanced ripening behavior of Mg-doped CdSe quantum dots
Sung, Yun-Mo,Kwak, Woo-Chul,Kim, Woong,Kim, Tae Geun Cambridge University Press (Materials Research Soc 2008 Journal of materials research Vol.23 No.7
<P>Pure CdSe and Mg-doped CdSe nanocrystal quantum dots were synthesized into the zinc-blende structure at a low temperature by the inverse micelle technique using paraffin oil and oleic acid as surface capping agents. The ripening behavior of the nanocrystals was monitored using the red shift in ultraviolet (UV)-visible light absorption peaks, and their size variation was estimated using the so-called, quantum confinement theory. The Lifshitz-Slyozov-Wagner (LSW) kinetics analyses were performed based on the variation in size according to the ripening temperature and time period. The activation energy (<I>Q</I>) and reaction rate constant (<I>K</I>o) were determined for the ripening reaction using Arrhenius-type plots. The kinetics analyses reveal that the volume diffusion through the liquid-phase solution is the governing mechanism for the ripening of both nanocrystals. The Mg-doped CdSe nanocrystals showed enhanced ripening kinetics due to the low activation energy for the volume diffusion.</P>
Yun, Beom-Sik,Lee, Mi-Ra,Oh, Chang-Jin,Cho, Jeong-Hee,Wang, Chun-Yan,Gu, Li Juan,Mo, Eun-Kyung,Sung, Chang-Keun The Korean Society of Ginseng 2010 Journal of Ginseng Research Vol.34 No.4
Black ginseng and white ginseng were extracted with 80% ethanol and evaluated for relative ginsenoside composition, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities, and antioxidant properties. As analyzed by HPLC, black ginseng contained a greater proportion of ginsenoside $Rg_3$ compared to white ginseng. White ginseng was characterized by undetectable ginsenoside $Rg_3$ but it contained more total ginsenosides than black ginseng. Black ginseng extract exhibited higher (p<0.05) free radical-scavenging activity, as well as higher antioxidant activities than white ginseng against 2,2-diphenyl-1-picryl-hydrazyl, superoxide dismutase, and xanthine oxidase, despite the fact that the total saponin content was higher in white ginseng than black ginseng. In addition, the black ginseng extract displayed greater AChE and BChE inhibitory activities. These results suggest that black ginseng has stronger effects on anti-oxidation and AChE and BChE inhibition than white ginseng.
( Yun Hee Kim ),( Min Kyu Choi ),( Rae Hong Jung ),( Sang Pil Yoon ),( Jun Yu ),( Hee Gu Choi ),( Soon Mo Ahn ),( Hyo Bang Moon ) 한국환경분석학회 2010 환경분석과 독성보건 Vol.13 No.1
Polycyclic aromatic hydrocarbons (PAHs) and fecal sterols were determined in the sediment from Gamak Bay in Korea, to investigate their distributions and impacts on benthic environment. Concentrations of 16 PAHs and 8 fecal sterols in Gamak Bay sediments ranged from 130 to 2,100 ng/g dry weight (mean 400 ng/g dry weight), and from 740 to 9,500 ng/g dry weight (mean 2,900 ng/g dry weight), respectively. Concentrations of coprostanol (Cop), which has been used as indicator of domestic pollution, ranged from 12 to 600 ng/g dry weight. Concentrations of PAHs and Cop in the sediment from Gamak Bay were similar to or lower than those reported for industrialized bays of Korea and other countries. No correlation between the levels of PAHs and fecal sterols was found in sediment from Gamak Bay, suggesting the differences of source and behavior for these chemicals in coastal environment. Diagnostic ratios and profiles of PAHs in Gamak Bay sediment showed a strong pyrolytic origin with a slight petrogenic contamination. The Cop/(Cop+cholestanol) and Cop/ cholesterol showed that the organic pollution in Gamak Bay was attributed to biogenic source rather than sewage pollution. Spearman correlation analyses and non-parametric multidimensional scaling (MDS) technique showed that distribution of fecal sterols was associated with benthic community structure in sediment from Gamak Bay.
( Sung Hyun Choi ),( Seok Yun Jung ),( Takayuki Asahara ),( Wonhee Suh ),( Sang Mo Kwon ),( Sang Hong Baek ) 한국조직공학·재생의학회 2012 조직공학과 재생의학 Vol.9 No.6
Cardiac stem/progenitor cells can be differentiated into cardiomyocytes in vitro using several differentiation methodologies. However, the methodology of cardiomyogenic induction in human c-kit positive progenitor cells (hCPCsc-kit+) was not fully demonstrated. Thus, the purpose of our study was to directly evaluate each cardiomyocyte induction system using hCPCsc-kit+. In this study, cardiomyocyte induction methodologies were divided into the following three groups; treatment with dexamethasone, 5-azacytidine, and co-treatment with 5-azacytidine and Transforming Growth Factor Beta 1 (TGF-β1), using different serum concentrations [2% or 10% fetal bovine serum (FBS)]. GATA4 and Nkx2-5, cardiac-specific transcription factors, were expressed in our hCPCsckit+. However, the GATA4 and Nkx2-5 expressions were significantly decreased in 10% FBS/cardiomyogenic induction system (p < 0.01), whereas the GATA4 and Nkx2-5 expressions were preserved in 2% FBS/cardiomyogenic induction system (p > 0.05). GATA4 and Nkx2-5 is crucial roles in cardiac development, thus we considered the low serum conditions more affected in our cardiomyogenic induction system. In addition, c-kit expression decreased significantly during cardiomyogenic differentiation. Importantly, we demonstrated that co-treated with 5-azacytidine and TGF-β1 led to an earlier expression pattern of alpha-sarcomeric actin (α-SA), implying that this cardiomyocyte induction system facilitates early cardiomyocyte differentiation of hCPCsc-kit+. Thus, the present study provides a pivotal cardiomyogenic differentiation methodology using hCPCsc-kit+ for basic or clinical research.
Sung-Mo Choi,Yeo-Sang Yun,Jin-Ho Kim 국제구조공학회 2006 Steel and Composite Structures, An International J Vol.6 No.4
The connection with combined cross diaphragm is developed for the connection of square CFT column and steel beam and proposed to be used for the frame with asymmetric span length. The structural characteristics of this connection lie in the penetration of the beam flange in the direction of major axis through the column for the smooth flow of stress. The purpose of this study is to analyze the dynamic behavior and stress flow of suggested connection and to evaluate the resistance to shock of connection. Four T-type CFT column-to-beam specimens; two with combined cross diaphragm and the others with interior and through diaphragms, the existing connection types, were made for cyclic load test guided by the load program of ANSI/AISC SSPEC 2002. The results show that the proposed connection is more efficient than existing ones in terms of strength, stress flow and energy absorption and satisfies the seismic performance required in the region of weak/moderate earthquakes.