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111.
Gong X Xie T Yu L Hesterberg M Scheide D Friedrich T Yu CA 《The Journal of biological chemistry》2003,278(28):25731-25737
An azido-ubiquinone derivative, 3-azido-2-methyl-5-methoxy[3H]-6-decyl-1,4-benzoquinone ([3H]azido-Q), was used to study the ubiquinone/protein interaction and to identify the ubiquinone-binding site in Escherichia coli NADH:ubiquinone oxidoreductase (complex I). The purified complex I showed no loss of activity after incubation with a 20-fold molar excess of [3H]azido-Q in the dark. Illumination of the incubated sample with long wavelength UV light for 10 min at 0 degrees C caused a 40% decrease of NADH:ubiquinone oxidoreductase activity. SDS-PAGE of the complex labeled with [3H]azido-Q followed by analysis of the radioactivity distribution among the subunits revealed that subunit NuoM was heavily labeled, suggesting that this protein houses the Q-binding site. When the [3H]azido-Q-labeled NuoM was purified from the labeled reductase by means of preparative SDS-PAGE, a 3-azido-2-methyl-5-methoxy-6-decyl-1,4-benzoquinone-linked peptide, with a retention time of 41.4 min, was obtained by high performance liquid chromatography of the protease K digest of the labeled subunit. This peptide had a partial NH2-terminal amino acid sequence of NH2-VMLIAILALV-, which corresponds to amino acid residues 184-193 of NuoM. The secondary structure prediction of NuoM using the Toppred hydropathy analysis showed that the Q-binding peptide overlaps with a proposed Q-binding motif located in the middle of the transmembrane helix 5 toward the cytoplasmic side of the membrane. Using the PHDhtm hydropathy plot, the labeled peptide is located in the transmembrane helix 4 toward the periplasmic side of the membrane. 相似文献
112.
Dichloroacetate (DCA) is an inhibitor of pyruvate dehydrogenase kinase (PDK), and recently it has been shown as a promising nontoxic antineoplastic agent. In this study, we demonstrated that DCA could induce autophagy in LoVo cells, which were confirmed by the formation of autophagosomes, appearance of punctate patterns of LC3 immunoreactivity and activation of autophagy associated proteins. Moreover, autophagy inhibition by 3-methyladenine (3-MA) or Atg7 siRNA treatment can significantly enhance DCA-induced apoptosis. To determine the underlying mechanism of DCA-induced autophagy, target identification using drug affinity responsive target stability (DARTS) coupled with ESI-Q-TOF MS/MS analysis were utilized to profile differentially expressed proteins between control and DCA-treated LoVo cells. As a result, Cathepsin D (CTSD) and thioredoxin-like protein 1 (TXNL1) were identified with significant alterations compared with control. Further study indicated that DCA treatment significantly promoted abnormal reactive oxygen species (ROS) production. On the other hand, DCA-triggered autophagy could be attenuated by N-acetyl cysteine (NAC), a ROS inhibitor. Finally, we demonstrated that the Akt-mTOR signaling pathway, a major negative regulator of autophagy, was suppressed by DCA treatment. To our knowledge, it was the first study to show that DCA induced protective autophagy in LoVo cells, and the potential mechanisms were involved in ROS imbalance and Akt-mTOR signaling pathway suppression. 相似文献
113.
Leixiang Yang Jingxu Gong Feng Wang Yongmin Zhang Yanguang Wang Xiaojiang Hao 《Journal of enzyme inhibition and medicinal chemistry》2013,28(4):399-404
In this work, we evaluated the antioxidant properties of the eight novel silybin analogues for their capacity to scavenge free radicals including superoxide anion radicals and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals in vitro. Compound 7d demonstrated an excellent antioxidant effect in scavenging superoxide anion free radical with an IC50 value of 26.5 μM, while the IC50 of quercetin (the reference compound) was 38.1 μM. Compounds 7b, 7e, 7h showed certain scavenging activities for both types of free radicals. 相似文献
114.
Huilin Pan Xia Lu Xiqian Yu Yong‐Sheng Hu Hong Li Xiao‐Qing Yang Liquan Chen 《Liver Transplantation》2013,3(9):1186-1194
Layered sodium titanium oxide, Na2Ti3O7, is synthesized by a solid‐state reaction method as a potential anode for sodium‐ion batteries. Through optimization of the electrolyte and binder, the microsized Na2Ti3O7 electrode delivers a reversible capacity of 188 mA h g?1 in 1 M NaFSI/PC electrolyte at a current rate of 0.1C in a voltage range of 0.0–3.0 V, with sodium alginate as binder. The average Na storage voltage plateau is found at ca. 0.3 V vs. Na+/Na, in good agreement with a first‐principles prediction of 0.35 V. The Na storage properties in Na2Ti3O7 are investigated from thermodynamic and kinetic aspects. By reducing particle size, the nanosized Na2Ti3O7 exhibits much higher capacity, but still with unsatisfied cyclic properties. The solid‐state interphase layer on Na2Ti3O7 electrode is analyzed. A zero‐current overpotential related to thermodynamic factors is observed for both nano‐ and microsized Na2Ti3O7. The electronic structure, Na+ ion transport and conductivity are investigated by the combination of first‐principles calculation and electrochemical characterizations. On the basis of the vacancy‐hopping mechanism, a quasi‐3D energy favorable trajectory is proposed for Na2Ti3O7. The Na+ ions diffuse between the TiO6 octahedron layers with pretty low activation energy of 0.186 eV. 相似文献
115.
Tomohiro Teraminami Atsushi Nakashima Mao Ominami Masanori Yamamoto Zhang Guo Sheng Ken Yoshikawa 《Landscape and Ecological Engineering》2013,9(2):249-257
Salix cheilophila Schneid. is a naturally occurring Salix species in Mu Us Sandy Land, Inner Mongolia, China. We focused on the morphological adaptability of S. cheilophila to sand dune burial. For morphological measurements, 32 S. cheilophila seedlings were removed from a community which was in the process of being buried by a shifting sand dune. Each seedling collected included the entire root system. We measured the number, length, and biomass of the adventitious roots, primary lateral roots, and taproot, and compared the morphological characteristics of the root system, including adventitious roots, for seedlings buried to various levels in the sand. The growth range of adventitious roots increased as the length of the buried portion of the main shoot increased. In addition, the total dry weight of all current-year shoots tended to increase gradually with increasing total dry weight of the adventitious roots. These results suggest that S. cheilophila tends to make use of the sedimentary sand layer that accompanies shifting sand dunes. However, there was no correlation between biomass or number of adventitious roots and the length of the buried part of the main shoot. Thus, S. cheilophila does not grow adventitious roots proportional to the buried part. These morphological characteristics of the root system, including the adventitious roots, may indicate that S. cheilophila has poor morphological adaptability to sand dune burial. 相似文献
116.
氯丙醇酯是国际上广泛关注的食品加工过程污染物,其水解产物氯丙醇对人体(特别是婴幼儿)危害风险较大。采用固相萃取与气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)联用技术,对食用植物油和含脂食品中的氯丙醇酯[3-氯-1,2-丙二醇脂肪酸酯(简称3-MCPD酯)和2-氯-1,3-丙二醇脂肪酸酯(简称2-MCPD酯)]进行检测。该方法准确度高(3-MCPD酯和2-MCPD酯的平均回收率分别为98.9%和96.5%)、灵敏度高(3-MCPD酯和2-MCPD酯的检出限分别为0.042 mg·kg-1和0.058 mg·kg-1)、重现性好(相对标准偏差均低于5%)。76批次监测样品中,3-MCPD酯和2-MCPD酯的含量分别为0.042~4.865 mg·kg-1(平均值为0.773 mg·kg-1)和0.058~2.592 mg·kg-1(平均值为0.469 mg·kg-1)。经机构间的协同验证和英国FAPAS样的能力验证,2种氯丙醇酯在0.200~3.000 mg·kg-1范围内线性良好,为进一步研究奠定了基础,同时也为食品加工企业严格控制生产过程建立了一种可行的检测方法。 相似文献
117.
Wang Ning Gao Qing Shi Jie Yulan Chen Ji Weimeng Sheng Xiumei Zhang Rui 《Molecular biology reports》2022,49(9):8727-8740
Molecular Biology Reports - During the pathogenesis and progression of diabetes, lipotoxicity is a major threat to the function and survival of pancreatic β-cells. To battle against the... 相似文献
118.
GKAP, a Novel Synaptic Protein That Interacts with the Guanylate Kinase-like Domain of the PSD-95/SAP90 Family of Channel Clustering Molecules 总被引:13,自引:2,他引:13 下载免费PDF全文
Eunjoon Kim Scott Naisbitt Yi-Ping Hsueh Anuradha Rao Adam Rothschild Ann Marie Craig Morgan Sheng 《The Journal of cell biology》1997,136(3):669-678
The molecular mechanisms underlying the organization of ion channels and signaling molecules at the synaptic junction are largely unknown. Recently, members of the PSD-95/SAP90 family of synaptic MAGUK (membrane-associated guanylate kinase) proteins have been shown to interact, via their NH2-terminal PDZ domains, with certain ion channels (NMDA receptors and K+ channels), thereby promoting the clustering of these proteins. Although the function of the NH2-terminal PDZ domains is relatively well characterized, the function of the Src homology 3 (SH3) domain and the guanylate kinase-like (GK) domain in the COOH-terminal half of PSD-95 has remained obscure. We now report the isolation of a novel synaptic protein, termed GKAP for guanylate kinase-associated protein, that binds directly to the GK domain of the four known members of the mammalian PSD-95 family. GKAP shows a unique domain structure and appears to be a major constituent of the postsynaptic density. GKAP colocalizes and coimmunoprecipitates with PSD-95 in vivo, and coclusters with PSD-95 and K+ channels/ NMDA receptors in heterologous cells. Given their apparent lack of guanylate kinase enzymatic activity, the fact that the GK domain can act as a site for protein– protein interaction has implications for the function of diverse GK-containing proteins (such as p55, ZO-1, and LIN-2/CASK). 相似文献
119.
120.
对天然羊草群落进行灌水和施肥后,测定了它们(灌水、灌水加施肥和对照)的群落光合速率。结果如下:1.在灌水、施肥加灌水处理后23天测定,处理群落的叶层高度分别比对照高8%和9%;群落LAI分别比对照高68.97%和99.93%;群落生物量分别比对照高41%和65.69%;群落日净光合量分别是对照的2.48倍和3.76倍;最大光合量分别是对照的2.82倍和3.12倍。2.灌水施肥处理后,羊草群落光合速率日变化的类型与对照基本一致,属于双峰型。唯独灌水加施肥群落(处理后3天)是单峰型,没有中午降低现象。看出较好的水肥条件能改变群落的日变化类型。3.在温湿度条件较差时或随着处理时间的推移,处理的效果越显著。第一阶段测定时,灌水、灌水加施肥处理的群落日净光合量分别是对照的1.26和1.17倍。第二阶段测定时,分别是对照的1.40和1.84倍。第三阶段测定时,分别是对照的2.48和3.76倍。 相似文献