• 생명과학회지
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• 제23권4호
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• pp.586-594
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• 2013

단백질 번역 후 O-GlcNAc 수식은 단백질 조절의 새로운 기전으로 대두되고 있다. 전통적인 당수식과 달리 O-GlcNAc 수식은 단 한번의 O-GlcNAc 전달로 이루어지며, 핵 및 세포질단백질 모두에 수식될 수 있다. O-GlcNAc은 이 분자를 끝으로 하는 최종수식으로 생각되어 왔으나, 최근의 논문(J Proteome Res. 2011 10:2725-2733)은 AP180 단백질에 O-GlcNAc-P가 존재함을 보고하였다. 이 논문은 O-GlcNAc-P가 일반적인 단백질수식인지에 대한 중요한 질문을 던진다. 이에 답하고자 저자들은 HEK293T 세포에 O-GlcNAc 인산화효소 NAGK를 DsRed2에 연결한 DsRed2-$NAGK_{WT}$ 혹은 효소활성이 없는 돌연변이 NAGK를 표현하는 DsRed2-$NAGK_{D107A}$를 표현시키고, 단백질 추출물을 얻어 2D-PAGE로 분리한 후 인산화 정도를 측정하여, $NAGK_{WT}$에 의하여 인산화가 증가되는 15개의 단백질 스폿을 선별하였다. 이 가운데 7개 스팟을 동정한 결과 2개의 스폿은 O-GlcNAc 수식 단백질인 $HSP90{\beta}$, 다른 2개의 스폿도 O-GlcNAc 수식 단백질인 ENO1로 동정되었으며, 나머지(dUTP nucleotidohydrolase mitochondrial isoform 2, glutathione S-transferase P, grp94)는 O-GlcNAc 수식 여부를 아직 모르는 단백질이였다. NAGK에 의하여 O-GlcNAc 단백질의 인산화가 증가된다는 사실은 O-GlcNAc이 인산화되어 O-GlcNAc-P로 수식됨을 시사하며, 따라서 본 연구의 결과는 O-GlcNAc이 최종 수식이 아님을 지지한다.

• Molecules and Cells
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• 제24권1호
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• pp.95-104
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• 2007

The mechanism of acacetin-induced apoptosis of human breast cancer MCF-7 cells was investigated. Acacetin caused 50% growth inhibition ($IC_{50}$) of MCF-7 cells at $26.4{\pm}0.7{\mu}M$ over 24 h in the MTT assay. Apoptosis was characterized by DNA fragmentation and an increase of sub-G1 cells and involved activation of caspase-7 and PARP (poly-ADP-ribose polymerase). Maximum caspase 7 activity was observed with $100{\mu}M$ acacetin for 24 h. Caspase 8 and 9 activation cascades mediated the activation of caspase 7. Acacetin caused a reduction of Bcl-2 expression leading to an increase of the Bax:Bcl-2 ratio. It also caused a loss of mitochondrial membrane potential that induced release of cytochrome c and apoptosis inducing factor (AIF) into the cytoplasm, enhancing ROS generation and subsequently resulting in apoptosis. Pretreatment of cells with N-acetylcysteine (NAC) reduced ROS generation and cell growth inhibition, and pretreatment with NAC or a caspase 8 inhibitor (Z-IETD-FMK) inhibited the acacetin-induced loss of mitochondrial membrane potential and release of cytochrome c and AIF. Stress-activated protein kinase/c-Jun $NH_4$-terminal kinase 1/2 (SAPK/JNK1/2) and c-Jun were activated by acacetin but extracellular-regulated kinase 1/2 (Erk1/2) nor p38 mitogen-activated protein kinase (MAPK) were not. Our results show that acacetin-induced apoptosis of MCF-7 cells is mediated by caspase activation cascades, ROS generation, mitochondria-mediated cell death signaling and the SAPK/JNK1/2-c-Jun signaling pathway, activated by acacetin-induced ROS generation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.11-11
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• 2008

ZnO has a very large exciton binding energy (60 meV) as well as thermal and chemical stability, which are expected to allow efficient excitonic emission, even at room temperature. ZnO based electronic devices have attracted increasing interest as the backplanes for applications in the next-generation displays, such as active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs), and in solid state lighting systems as a substitution for GaN based light emitting diodes (LEDs). Most of these electronic devices employ the electrical behavior of n-type semiconducting active oxides due to the difficulty in obtaining a p-type film with long-term stability and high performance. p-type ZnO films can be produced by substituting group V elements (N, P, and As) for the O sites or group I elements (Li, Na, and K) for Zn sites. However, the achievement of p-type ZnO is a difficult task due to self-compensation induced from intrinsic donor defects, such as O vacancies (Vo) and Zn interstitials ($Zn_i$), or an unintentional extrinsic donor such as H. Phosphorus (P) doped ZnO thin films were grown on c-sapphire substrates by radio frequency magnetron sputtering with various Ar/ $O_2$ gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio with out post-annealing. The P-doped ZnO films grown at a Ar/ $O_2$ ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of $10^{-17}cm^{-3}$ and $2.5cm^2/V{\cdot}s$, respectively. X-ray diffraction showed that the ZnO (0002) peak shifted to lower angle due to the positioning of $p^{3-}$ ions with a smaller ionic radius in the $O^{2-}$ sites. This indicates that a p-type mechanism was due to the substitutional Po. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction LEO showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.

• The Korean Journal of Pain
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• 제1권1호
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• pp.64-73
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• 1988

Recent studios have shown that narcotic drags produce an unusually intense, prolonged and segmental analgesic action in man whoa injected into the spinal subarachnoid or epidural space (Wang et al, 1979; Behar et al, 1979; Cousins et al, 1979; Magora et a., 1980, Johnston and McCaughey, 1980). Since 1960, many investigators claimed that low molecular weight(LMW) dextran increased the clinical duration of lidocaine(Loder, 1960; Loder, 1962), tetracaine (Chinn and Wirjoatmadja, 1967) and bupivacaine(Kaplan et al, 1975) in man but the mechanism of the action of dextran was unclear. But Curtiss and Scurlock(1979), and Buckled and Fink(1979) claimed that LMW dextran has no effect on the duration of action of bupivacaine in animal studies. The present study was performed to evaluate the clinical efficacy of analgesia by the thoracic epidural injection of morphine and bupivacaine mixture for the relief of pain due to fractured or contused ribs, to evaluate the duration of analgesic effect by the use of the above mixture in a hypertonic solution(dextran 70 or 50% dextrose in water) and to observe the possibility of improvement in the lung function after the pain block. The complications following the pain block were also observed. The 50 single thoracic epidural injections of the mixture were divided into three groups : Group 1(n=15) served as a control group and drags used for the relief of pain were as follows(Mean$\pm$S.D.): morphine($2.13{\pm}1.64\;mg$), 0.5% bupivacaine($3.10{\pm}1.04\;ml$) and 0.9% saline($3.64{\pm}1.11\;ml$). Group 2(n=16) serves as an experimental group and drugs were as follows(Mean$\pm$S.D.): morphine($2.13{\pm}0.72\;mg$), 0.5% bupivacaine($3.06{\pm}0.77\;ml$) and dextran 70($3.75{\pm}1.29\;ml$). Group 3 (n=19) served as an experimental group and drags were as follows(Mean$\pm$S.D.) : morphine($2.42{\pm}0.51\;mg$), 0.5% bupivacaine($3.21{\pm}0.71\;ml$) and 50% dextrose in water($3.58{\pm}1.11\;ml$). The results are were follows: 1) The Dumber of patients who obtained excellent and good analgesic effects following the block were greater in the experimental Croup 2(94%) and Group 3 (90%) than theme of the control Group 1 (80%). 2) The duration of pain relief which lasted more than 3 days after the epidural block was longer in the experimental Group 2 (81%) and Group 3 (75%) than those of the control Croup 1(67%). 3) The pulmonary reserve(FVC%+FEV 1.0%) of 27 cases who were treated by the pain block between 1 and 31 drys following the chest injury was increased to about 13% than those before the block, and that of 13 cases between 32 and 82 days following the chest injury was decreased to about 4% than those before the block. 4) Of the complications following the pain block, there were 5 cased(10%) of nausea within 2 hours following the block, 4 cases(8%) of vomiting after 2 hours following the block, 10 cases(20%) of pruritus after 3~4 hours following the block, 17 cases(34%) of transient urinary retention which tasted 8 to 19 hours, 3 cases(6%) of headache within 2 hoers following the block and 2 cases(4%) of dural puncture. In conclusion, it is suggested that the clinical duration of analgesic effect produced by morphine and bupivacaine mixture can be prolonged by addition of the hypertonic solution to the mixture.

• Journal of Biosystems Engineering
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• 제3권2호
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• pp.34-34
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• 1978

동력경운깅가 일반 경사지에서 견인주행하는 경우 견인주행성능과 주행특성을 구명하기 위하여 토양의 종류 및 상태는 일정하게 하고 지면의 기하학적 조건과 견인주행속도 및 견인하중을 변수로 하여 외부동력전달계의 시점인 좌우차륜과 토양간에 발생하는 차륜구동력 및 굴름정항과 Engine에서 구동륜까지 내부전달계를 통하여 전달된 동력의 이론치와 실험치와의 부합여부를 검정하고 부가적으로 동력경운기가 경사지기계화의 동력기로써의 가능성여부와 문제점을 찾으려한다.

• 한국전산유체공학회지
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• 제17권4호
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• pp.16-23
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• 2012

Current display manufacturing processes apply thermal treatment of glass backplanes widely for hydrogen degassing, crystallization of thin-films, tempering, forming, and precompaction. Estimation of the characteristics of transient heating stages and thermal non-uniformities on a single glass substrate or in a stack of glasses are extremely helpful to understand non-homogeneity of mechanical and electronic features of nano/micro structures of end products. Based on simple heat transfer models and using an electric muffle furnace, temperature variations in a glass stack were predicted and measured for glass backplanes of $1.5{\times}1.85m^2$ in size and 0.7 mm in thickness. Except for the period of putting glass backplanes into the furnace, thermal radiation was the major heating mechanism for the treatment and theoretical predictions agreed well to the experimental temperatures on the backplanes. Using the theoretical model, thermal fields for a glass stack of glass-size, $2.2{\times}2.5m^2$, and of the number of sheets, 1 to 12, were calculated for practical design and manufacturing of the muffle furnace for large-scale displays, e.g. up to $8^{th}$ generation.

• BMB Reports
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• 제31권1호
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• pp.25-30
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• 1998

Kinetic studies of L-Alanine dehydrogenase from Bacillus subtilis-catalyzed reactions in the presence of $Zn^{2+}$ were carried out. The substrate (L-alanine) saturation curve is hyperbolic in the absence of the metal ion but it becomes sigmoidal when $Zn^{2+}$ is added to the reaction mixture indicating the positive cooperative binding of the substrate in the presence of zinc ion. The cooperativity of substrate binding depends on the xinc ion concentration: the Hill coefficients ($n_H$) varied from 1.0 to 1.95 when the zinc ion concentration varied from 0 to $60\;{\mu}m$. The inhibition of AlaDH by $Zn^{2+}$ is reversible and noncompetitive with respect to $NAD^+$ ($K_i\;=\;5.28{\times}10^{-5}\;M$). $Zn^{2+}$ itself binds to AlaDH with positive cooperativity and the cooperativity is independent of substrate concentration. The Hill coefficients of substrate biding in the presence of $Zn^{2+}$ are not affected by the enzyme concentration indicating that $Zn^{2+}$ binding does not change the polymerization-depolymerization equilibria of the enzyme. Among other metal ions, $Zn^{2+}$ appears to be a specific reversible inhibitor inducing conformational change through the intersubunit interaction. These results indicate that $Zn^{2+}$ is an allosteric competitive inhibitor and substrate being a non-cooperative per se, excludes the $Zn^{2+}$ from its binding site and thus exhibits positive cooperativity. The allosteric mechanism of AlaDh from Bacillus subtilis is consistent with both MWC and Koshland's allosteric model.

• Fisheries and Aquatic Sciences
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• 제21권6호
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• pp.15.1-15.9
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• 2018

Background: Inflammation has been known to associate with many human diseases. The objective of this study was to evaluate an anti-inflammatory effect of ozonated krill (Euphausia superba) oil, which was prepared by the treatment of krill oil using ozone gas. The anti-inflammatory activity was evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Results: Ozonated krill oil significantly inhibited nitric oxide (NO) production and suppressed the mRNA and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW 264.7 macrophages. Ozonated krill oil also reduced the mRNA expression of inflammatory cytokines such as interleukin (IL)-$1{\beta}$, IL-6, and tumor necrosis factor (TNF)-${\alpha}$ in LPS-stimulated RAW 264.7 macrophages. To elucidate the mechanism underlying the anti-inflammatory activity of ozonated krill oil, we evaluated the effects of ozonated krill oil on the activation of mitogen-activated protein kinases (MAPKs) pathway. Ozonated krill oil suppressed the LPS-stimulated phosphorylation of p38 MAPK and c-Jun N-terminal kinases (JNK). Conclusion: This study revealed that the ozonated krill oil exhibited an anti-inflammatory effect in LPS-stimulated RAW 264.7 macrophages. To the best of our knowledge, this is the first report that ozonated krill oil suppressed pro-inflammatory mediator and cytokine expression in LPS-stimulated RAW 264.7 macrophages by inhibiting the phosphorylation of p38 MAPK and JNK.

• Advances in Energy Research
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• 제5권3호
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• pp.219-226
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• 2017

Electrochemical double layer capacitors (EDLCs) have received a tremendous interest due to their suitability for diverse applications. They have been fabricated using different carbon based electrodes including activated carbons, single walled/multi walled carbon nano tubes. But, graphite which is one of the natural resources in Sri Lanka has not been given a considerable attention towards using for EDLCs though it is a famous carbon material. On the other hand, EDLCs are well reported with various liquid electrolytes which are associated with numerous drawbacks. Gel polymer electrolytes (GPE) are well known alternative for liquid electrolytes. In this paper, it is reported about an EDLC fabricated with a nano composite polyethylene oxide based GPE and two Sri Lankan graphite based electrodes. The composition of the GPE was [{(10PEO: $NaClO_4$) molar ratio}: 75wt.% PC] : 5 wt.% $TiO_2$. GPE was prepared using the solvent casting method. Two graphite electrodes were prepared by mixing 85% graphite and 15% polyvinylidenefluoride (PVdF) in acetone and casting n fluorine doped tin oxide glass plates. GPE film was sandwiched in between the two graphite electrodes. A non faradaic charge discharge mechanism was observed from the Cyclic Voltammetry study. GPE was stable in the potential windows from (-0.8 V-0.8 V) to (-1.5 V-1.5 V). By increasing the width of the potential window, single electrode specific capacity increased. Impedance plots confirmed the capacitive behavior at low frequency region. Galvanostatic charge discharge test yielded an average discharge capacity of $0.60Fg^{-1}$.

• 생명과학회지
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• 제19권4호
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• pp.520-525
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• 2009

영아형 바텐병은 PPT1 결핍 및 기능장애로 인해 발병하며, 12,500명 당 1명의 발병률을 가진 신경 퇴행 질환이다. 전 세계적으로 수많은 연구가 진행 중 이지만, 아직 명확하게 밝혀진 발병원인 및 치료방법에 대해서는 알려지고 있지 않다. 본 연구에서는 뇌에서 풍부하게 발현되는 neurogranin의 발현수준이 WT과 EBD KO 쥐에서 어떤 변화를 보이는지 확인하기 위해 mRNA, 단백질, 배양된 neurospheres를 이용하여 실험을 수행하였다. real-time PCR을 통한 neurogranin의 발현수준 비교 결과 WT에서는 노화와 무관하게neurogranin mRNA 수준에 차이가 없었으나, EBD KO 쥐에서는 노화가 진행됨에 따라 neurogranin mRNA 발현수준이 감소하였으며, 뇌에서 추출된 단백질을 이용한 western blot 분석에서도 real-time PCR과 동일한 결과를 확인할 수 있었다. 또한 WT, EBD KO 쥐의 태아로 부터 neural stem cell 인 neurospheres를 배양하여 western blot 분석을 수행한 결과 PPT1 결핍에 의해 neurogranin의 정상적인 인산화에 문제가 발생함을 확인하였다. 이러한 결과들을 바탕으로 neurospheres에 산화스트레스 유발물질인 $H_2O_2$를 처리하였고, 24시간 경과 후 항산화제인 NAC을 처리하자 $H_2O_2$를 처리한 시료에서는 mock control인 인산화된 neurogranin에 비해 그 수준이 증가하였으며, $H_2O_2$ 처리 후 NAC을 투여한 시료의 인산화 수준은 mock control 보다는 높았지만 $H_2O_2$만을 처리한 시료 수준보다 neurogranin의 인산화 정도가 감소하는 결과를 확인하였다. 이러한 결과들을 통해 PPT1 결핍으로 인해 신경세포 내에 과다하게 인산화된 neurogranin이 존재하며, neurogranin 인산화 정도는 세포가 지닌 산화스트레스 정도에 의해 변화함을 알 수 있었다. 또한 항산화제를 사용하여 세포의 산화스트레스 수준을 감소시킬 경우 neurogranin의 기능을 정상적으로 회복시킬 수 있는 가능성을 확인하였다.