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排序方式: 共有220条查询结果,搜索用时 15 毫秒
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Youichi Shinozaki Koji Sumitomo Makoto Tsuda Schuichi Koizumi Kazuhide Inoue Keiichi Torimitsu 《PLoS biology》2009,7(5)
The ATP-gated P2X4 receptor is a cation channel, which is important in various pathophysiological events. The architecture of the P2X4 receptor in the activated state and how to change its structure in response to ATP binding are not fully understood. Here, we analyze the architecture and ATP-induced structural changes in P2X4 receptors using fast-scanning atomic force microscopy (AFM). AFM images of the membrane-dissociated and membrane-inserted forms of P2X4 receptors and a functional analysis revealed that P2X4 receptors have an upward orientation on mica but lean to one side. Time-lapse imaging of the ATP-induced structural changes in P2X4 receptors revealed two different forms of activated structures under 0 Ca2+ conditions, namely a trimer structure and a pore dilation-like tripartite structure. A dye uptake measurement demonstrated that ATP-activated P2X4 receptors display pore dilation in the absence of Ca2+. With Ca2+, the P2X4 receptors exhibited only a disengaged trimer and no dye uptake was observed. Thus our data provide a new insight into ATP-induced structural changes in P2X4 receptors that correlate with pore dynamics. 相似文献
65.
Junco Nagata Youichi Sonoda Keiko Hamaguchi Naoki Ohnishi Soh Kobayashi Ken Sugimura Fumio Yamada 《Conservation Genetics》2009,10(4):1121-1123
We report on the isolation and characterization of eight polymorphic and five monomorphic microsatellites in the Amami rabbit
(Pentalagus furnessi). Microsatellite polymorphism was determined using 25 individuals. There were 2–11 alleles for each polymorphic locus with
heterozygosity ranging between 0.08 and 0.76. Linkage disequilibrium was not suggested between any pairs among the eight polymorphic
loci. We suggest that these primers be used in future studies to monitor population size, determine dispersal patterns, and
genetic diversity within and between populations of this and related species. 相似文献
66.
Human T-Cell Leukemia Virus Type 1 Tax Protein Abrogates Interleukin-2 Dependence in a Mouse T-Cell Line 总被引:5,自引:3,他引:2 下载免费PDF全文
67.
Takeda K Nishiyama Y Yoda K Watanabe T Nimura-Matsune K Mura K Tokue C Katoh T Kawasaki S Niimura Y 《Bioscience, biotechnology, and biochemistry》2004,68(1):20-27
Peroxiredoxin (Prx) constitutes a large family of enzymes found in microorganisms, animals, and plants, but the detection of the activities of Prx-linked hydroperoxide reductases (peroxiredoxin reductases) in cell extracts, and the purification based on peroxide reductase activity, have only been done in bacteria and Trypanosomatidae. A peroxiredoxin reductase (NADH oxidase) from a bacterium, Amphibacillus, displayed only poor activities in the presence of purified Prx from Saccharomyces or Synechocystis, while it is highly active in the presence of bacterial Prx. These results suggested that an enzyme system different from that in bacteria might exist for the reduction of Prx in yeast and cyanobacteria. Prx-linked hydroperoxide reductase activities were detected in cell extracts of Saccharomyces, Synechocystis, and Chlorella, and the enzyme activities of Saccharomyces and Chlorella were induced under vigorously aerated culture conditions and intensive light exposure conditions, respectively. Partial purification of Prx-linked peroxidase from the induced yeast cells indicated that the Prx-linked peroxidase system consists of two protein components, namely, thioredoxin and thioredoxin reductase. This finding is consistent with the previous report on its purification based on its protein protection activity against oxidation [Chae et al., J. Biol. Chem., 269, 27670-27678 (1994)]. In this study we have confirmed that Prx-linked peroxidase activity are widely distributed, not only in bacteria species and Trypanosomatidae, but also in yeast and photosynthetic microorganisms, and showed reconstitution of the activity from partially purified interspecies components. 相似文献
68.
Banskota AH Nguyen NT Tezuka Y Le Tran Q Nobukawa T Kurashige Y Sasahara M Kadota S 《Life sciences》2004,74(22):2781-2792
The effects of secoisolariciresinol (1) and isotaxiresinol (2), two major lignans isolated from the wood of Taxus yunnanensis, on tumor necrosis factor-alpha (TNF-alpha)-dependent hepatic apoptosis induced by D-galactosamine (d-GalN)/lipopolysaccharide (LPS) were investigated in mice. Co-administration of d-GalN (700 mg/kg) and LPS (10 microg/kg) resulted in a typical hepatic apoptosis characterized by DNA fragmentation and the formation of apoptotic bodies. Serum glutamic pyruvic transaminase (sGPT) and glutamic oxaloacetic transaminase (sGOT) levels were also raised at 8 h after d-GalN/LPS intoxication due to a severe necrosis of hepatocytes. Pre-administration of 1 or 2 (50, 10 mg/kg, i.p.) 12 and 1 h before d-GalN/LPS significantly reduced DNA fragmentation and prevented chromatin condensation, apoptotic body formation and hepatitis. Pro-inflammatory cytokines such as TNF-alpha and interferon-gamma (IFN-gamma) secreted from LPS-activated macrophages are important mediators of hepatocyte apoptosis in this model. Pre-treatment with 1 or 2 significantly inhibited the elevation of serum TNF-alpha and IFN-gamma levels. In a separate experiment, both lignans had a significant dose-dependent protective effect on d-GalN/TNF-alpha-induced cell death in primary cultured mouse hepatocytes and TNF-alpha-mediated cell death in murine L929 fibrosarcoma cells. These results indicated that 1 and 2 prevent d-GalN/LPS-induced hepatic injury by inhibiting hepatocyte apoptosis through the blocking of TNF-alpha and IFN-gamma production by activated macrophages and direct inhibition of the apoptosis induced by TNF-alpha. 相似文献
69.
Posttranscriptional regulation of human ABCA7 and its function for the apoA-I-dependent lipid release 总被引:2,自引:0,他引:2
70.
Depletion of definitive gut endoderm in Sox17-null mutant mice 总被引:13,自引:0,他引:13
Kanai-Azuma M Kanai Y Gad JM Tajima Y Taya C Kurohmaru M Sanai Y Yonekawa H Yazaki K Tam PP Hayashi Y 《Development (Cambridge, England)》2002,129(10):2367-2379