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Agrobacterium transformation 에 의해 Manganese SOD가 과발현된 transgenic tobacco의 개발에 대한 연구
徐廷彬,金榮照,李宇成 성균관대학교 기초과학연구소 1995 論文集 Vol.46 No.2
식물체는 냉해, 가뭄, air pollutants 등과 같은 다양한 외부 환경적인 스트레스에 노출되어짐으로써 매우 활동적인 oxygen radicals 생성을 유도한다. 이러한 활동적인 oxygen radicals 는 식물체 내의 수 많은 생리적 문제를 유발시킨다. 이러한 스트레스에 적응하고자 식물체 내에는 다양한 방어 기작이 있으며, 그 중 하나가 superoxide를 Hydrogen peroxide로 바꾸는 효소인 superoxide dismutase (SOD, EC 1.15.1.1)이다. 방어 기작에 있어서 SOD의 역할을 조사해 보고자, 본 실험에서는 담배의 엽록체에 완두의 manganese SOD를 과발현시킨 형질 전환 식물체를 개발하였다. Northern hybridization과 SOD activity gel staining을 해 본 결과, 이러한 형질 전환된 담배 엽록체 내에서 완두의 manganese SOD가 안정적으로 발현되고 있음을 확인할 수 있었다. Upon exposure of plant to diverse environmental stress such as chilling, drought, and air pollutants, the activated oxygen radicals are actively produced. These reactive oxygen species are associated with a number of physiological disorders in plant. One of the enzymes involved in the defense is superoxde dismutase (SOD, EC 1.15.1.1) which converts superoxide into hydrogen peroxide. To test the role of SOD in the defense system, We produce transgenic plants which are overexpressed Mn SOD of pea (Pisum sativum L.) in chloroplasts of tobacco (Nicotiana tabacum L. cv Xanthi). Using Northern hybridization and SOD activity gel staining, it was confirmed that these transgenic plants overexpressed the introduced gene.
서정빈,정준영,장대식,김정목,김정희 한국응용약물학회 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.6
Betulinic acid (BA), a natural pentacyclic triterpene found in many medicinal plants is known to have various biological activity including tumor suppression and anti-inflammatory effects. In this study, the cell-death induction effect of BA was investigated in BV-2 microglia cells. BA was cytotoxic to BV-2 cells with IC50 of approximately 2.0 mM. Treatment of BA resulted in a dose-dependent chromosomal DNA degradation, suggesting that these cells underwent apoptosis. Flow cytometric analysis further confirmed that BA-treated BV-2 cells showed hypodiploid DNA content. BA treatment triggered apoptosis by decreasing Bcl-2 levels, activation of capase-3 protease and cleavage of PARP. In addition, BA treatment induced the accumulation of p62 and the increase in conversion of LC3-I to LC3-II, which are important autophagic flux monitoring markers. The increase in LC3-II indicates that BA treatment induced autophagosome formation, however, accumulation of p62 represents that the downstream autophagy pathway is blocked. It is demonstrated that BA induced cell death of BV-2 cells by inducing apoptosis and inhibiting autophagic flux. These data may provide important new information towards understanding the mechanisms by which BA induce cell death in microglia BV-2 cells.
THE CONTRIBUTION OF STELLAR WINDS TO COSMIC RAY PRODUCTION
서정빈,강혜성,류동수 한국천문학회 2018 Journal of The Korean Astronomical Society Vol.51 No.2
Massive stars blow powerful stellar winds throughout their evolutionary stages from the main sequence to Wolf-Rayet phases. The wind mechanical energy of a massive star deposited to the interstellar medium can be comparable to the explosion energy of a core-collapse supernova that detonates at the end of its life In this study, we estimate the kinetic energy deposition by massive stars in our Galaxy by considering the integrated Galactic initial mass function and modeling the stellar wind luminosity. The mass loss rate and terminal velocity of stellar winds during the main sequence, red supergiant, and Wolf-Rayet stages are estimated by adopting theoretical calculations and observational data published in the literature. We find that the total stellar wind luminosity by all massive stars in the Galaxy is about ${\mathcal L}_{\rm w} \approx 1.1\times 10^{41} \ergs$, which is about 1/4 of the power of supernova explosions, ${\mathcal L}_{\rm SN} \approx 4.8\times 10^{41} \ergs$. If we assume that $\sim 1-1$ \% of the wind luminosity could be converted to Galactic cosmic rays (GCRs) through collisonless shocks such as termination shocks in stellar bubbles and superbubbles, colliding-wind shocks in binaries, and bow-shocks of massive runaway stars, stellar winds are expected to make a significant contribution to GCR production, though lower than that of supernova remnants.