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221.
X. H. Bai D. W. Wang Y. Luan X. P. Yu C. J. Liu 《Cellular and molecular life sciences : CMLS》2009,66(4):667-680
ADAMTS-12, a metalloproteinase that belongs to ADAMTS family, is strongly upregulated during chondrogenesis and demonstrates
prominent expression in the growth plate chondrocytes. ADAMTS-12 potently inhibits chondrocyte differentiation, as revealed
by altered expression of both early and later genes critical for chondrogenesis. In addition, ADAMTS-12-mediated inhibition
of chondrogenesis depends on its enzymatic activity, since its point mutant lacking enzymatic activity completely loses this
activity. Furthermore, the C-terminal four thrombospondin motifs known to bind COMP substrate is necessary for its full proteolytic
activity and inhibition of chondrocyte differentiation. Mechanism studies demonstrate that ADAMTS-12 induces PTHrP, whereas
it inhibits IHH during chondrogenesis. Furthermore, PTHrP induces ADAMTS-12 and ADAMTS-12 is hardly detectable in PTHrP-/-growth
plate chondrocytes. Importantly, knocking down ADAMTS-12 mRNA levels or blocking ADAMTS-12 activity almost abolishes the PTHrP-mediated
inhibition of type X collagen expression. Collectively, these findings demonstrate that ADAMTS-12, a downstream molecule of
PTHrP signaling, is a novel regulator of chondrogenesis.
X. H. Bai, D.W. Wang: These two authors contributed equally to this work. 相似文献
222.
G. Zhao X.-W. Zheng G.-W. Qin Y. Gai Z.-H. Jiang L.-H. Guo 《Cellular and molecular life sciences : CMLS》2009,66(9):1617-1629
Cocktail recipes containing Psoralea corylifolia seeds (PCS) are used to empirically treat Parkinson disease. A PCS isolate Δ3,2-hydroxybakuchiol (BU) can inhibit dopamine uptake in dopamine transporter (DAT) transfected Chinese hamster ovary (CHO)
cells, and dopamine reuptake blockade may provide an alternative approach for ameliorating parkinsonism. Here, we assessed
the potential dopaminergic neuroprotective, and antiparkinsonian-like activity of BU. BU sample size was increased by using
a scale-up extraction paradigm. Pharmacologically, BU significantly protected SK-N-SH cells from 1-methyl-4-phenylpyridinium
(MPP+) insult, produced striking inhibitory actions on dopamine/norepinephrine uptake and WIN35,428 binding in synaptosomes on
in vivo administration, and significantly preventing poor performance on rotarod and dopaminergic loss in substantia nigra in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
(MPTP) mice. BU acts by protecting dopaminergic neurons from MPP+ injury and preventing against MPTP-induced behavioral and histological lesions in the Parkinson’s disease (PD) model, possibly
by inhibiting monoamine transporters. These findings suggest that BU could be meaningful in PD treatment.
Received 14 January 2009; received after revision 22 February 2009; accepted 10 March 2009 相似文献
223.
Molecular mechanisms of spider silk 总被引:2,自引:0,他引:2
Hu X Vasanthavada K Kohler K McNary S Moore AM Vierra CA 《Cellular and molecular life sciences : CMLS》2006,63(17):1986-1999
Spiders spin high-performance silks through the expression and assembly of tissue-restricted fibroin proteins. Spider silks
are composite protein biopolymers that have complex microstructures. Retrieval of cDNAs and genomic DNAs encoding silk fibroins
has revealed an association between the protein sequences and structure-property relationships. However, before spider silks
can be subject to genetic engineering for commercial applications, the complete protein sequences and their functions, as
well as the details of the spinning mechanism, will require additional progress and collaborative efforts in the areas of
biochemistry, molecular biology and material science. Novel approaches to reveal additional molecular constituents embedded
in the spider fibers, as well as cloning strategies to manipulate the genes for expression, will continue to be important
aspects of spider biology research. Here we summarize the molecular characteristics of the different spider fibroins, the
mechanical properties and assembly process of spidroins and the advances in protein expression systems used for recombinant
silk production. We also highlight different technical approaches being used to elucidate the molecular constituents of silk
fibers.
Received 28 February 2006; received after revision 14 April 2006; accepted 22 May 2006
X. Hu and K. Vasanthavada contributed equally to this work. 相似文献
224.
Wu J Feng Y Xie D Li X Xiao W Tao D Qin J Hu J Gardner K Judge SI Li QQ Gong J 《Cellular and molecular life sciences : CMLS》2006,63(21):2538-2545
Cyclin-dependent kinase 1 (CDK1) is a major component of the cell cycle progression engine. Recently, several investigations
provided evidence demonstrating that unscheduled CDK1 activation may also be involved in apoptosis in cancerous cells. In
this article, we demonstrate that X-ray irradiation induced G1 arrest in MOLT-4 lymphocytic leukemia cells, the arrest being
accompanied by reduction in the activity of CDK2, but increased CDK1 activity and cell apoptosis in the G1 phase. Interestingly,
this increase in CDK1 and apoptosis by ionizing radiation was prevented by pretreatment with the CDK1 inhibitor, roscovitine,
suggesting that CDK1 kinase activity is required for radiation-induced apoptotic cell death in this model system. Furthermore,
cyclin B1 and CDK1 were detected co-localizing and associating in G1 phase MOLT-4 cells, with the cellular lysates from these
cells revealing a genotoxic stress-induced increase in CDK1 phosphorylation (Thr-161) and dephosphorylation (Tyr-15), as analyzed
by postsorting immunoprecipitation and immunoblotting. Finally, X-irradiation was found to increase Bcl-2 phosphorylation
in G1 phase cells. Taken together, these novel findings suggest that CDK1 is activated by unscheduled accumulation of cyclin
B1 in G1 phase cells exposed to X-ray, and that CDK1 activation, at the wrong time and in the wrong phase, may directly or
indirectly trigger a Bcl-2-dependent signaling pathway leading to apoptotic cell death in MOLT-4 cells.
Received 30 March 2006; received after revision 23 June 2006; accepted 24 August 2006
J. Wu and Y. Feng contributed equally to this work. 相似文献
225.
226.
Zhu X Su B Wang X Smith MA Perry G 《Cellular and molecular life sciences : CMLS》2007,64(17):2202-2210
Oxidative stress is one of the earliest events of Alzheimer disease (AD), with implications as an important mediator in the
onset, progression and pathogenesis of the disease. The generation of reactive oxygen species (ROS) and its consequent cellular
damage/response contributes to much of the hallmark AD pathology seen in susceptible neurons. The sources of ROS-mediated
damage appear to be multi-faceted in AD, with interactions between abnormal mitochondria, redox transition metals, and other
factors. In this review, we provide an overview of these potential causes of oxidative stress in AD. 相似文献
227.
1 Results 2-pyrazolines and carbaozole derivatives are well known fluorescent compounds with high quantum yields[1],and have been investigated in many other respects[2,3].In this paper,carbazole radical was introduced to pyrazoline ring on C-5,and a novel derivative,named 1-phenyl-3-biphenyl-5-(N-ethyl carbazole-3-yl)-2-pyrazoline (PBEP) (5) was synthesized: The product PBEP was characterized by IR,1H NMR,and elementary analysis.Yield: 47.2%.M.P 104-106 ℃.1H NMR (CDCl3) δ/10-6: 1.5(3H,—CH3).2.4(2H,—... 相似文献
228.
许双魁 《西北大学学报(自然科学版)》1999,29(4):301-304
作为基础数学在经济运动规律分析预测方面的应用,将 M arkov 过程理论,应用于股票交易市场,对股价综合指数的涨(跌)幅度,进行状态分类,建立起对市场运行周期、稳态概率、稳定程度、投资利润等的分析预测模型,并利用这一模型对上海证券交易所股价综合的部分历史数据作了相应的分析,得到了较为理想的结果。 相似文献
229.
基于GT的过程机械快速设计系统的开发 总被引:1,自引:0,他引:1
徐鸿翔 《江苏技术师范学院学报》2006,12(6):57-62
过程机械的设计直接关系到产品的质量、成本和可靠性。在分析过程机械设计的特点和现状的基础上,运用成组技术构建了一个基于成组技术的过程机械快速设计系统,并且对开发过程中的零件分类方法、GT码的编制、编码检索与相似性判别以及三维设计系统的二次开发等关键技术进行了阐述。快速设计系统的使用可以缩短产品设计周期,使产品快速面市,提高产品的竞争力。 相似文献
230.