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81.
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83.
Malatesta M Scassellati C Meister G Plöttner O Bühler D Sowa G Martin TE Keidel E Fischer U Fakan S 《Experimental cell research》2004,292(2):312-321
Mutations in the survival of motor neuron (SMN) gene are the major cause of spinal muscular atrophy (SMA). The SMN gene encodes a 38-kDa protein that localises in the cytoplasm and in nuclear bodies termed Gemini of coiled bodies (gems). When visualised by immunofluorescence microscopy, gems often appeared either in close proximity to, or entirely overlapping with coiled (Cajal) bodies (CBs) implying a possible functional relationship between these nuclear domains. With the aim of identifying subnuclear compartments corresponding to gems, we have investigated the intranuclear localisation of SMN and of its interacting protein Gemin2 by immunoelectron microscopy in cultured cells and in liver cells of hibernating dormouse. These antigens are highly enriched in round-shaped electron-dense fibro-granular clusters (EFGCs), which also display a biochemical composition similar to gems visualised by immunofluorescence microscopy. Our data reveal a novel SMN/Gemin2 containing nuclear domain and support the idea that it represents the structural counterpart of gems seen in the light microscope. 相似文献
84.
Calcium and mitochondria 总被引:8,自引:0,他引:8
The literature suggests that the physiological functions for which mitochondria sequester Ca(2+) are (1). to stimulate and control the rate of oxidative phosphorylation, (2). to induce the mitochondrial permeability transition (MPT) and perhaps apoptotic cell death, and (3). to modify the shape of cytosolic Ca(2+) pulses or transients. There is strong evidence that intramitochondrial Ca(2+) controls both the rate of ATP production by oxidative phosphorylation and induction of the MPT. Since the results of these processes are so divergent, the signals inducing them must not be ambiguous. Furthermore, as pointed out by Balaban [J. Mol. Cell. Cardiol. 34 (2002 ) 11259-11271], for any repetitive physiological process dependent on intramitochondrial free Ca(2+) concentration ([Ca(2+)](m)), a kind of intramitochondrial homeostasis must exist so that Ca(2+) influx during the pulse is matched by Ca(2+) efflux during the period between pulses to avoid either Ca(2+) buildup or depletion. In addition, mitochondrial Ca(2+) transport modifies both spatial and temporal aspects of cytosolic Ca(2+) signaling. Here, we look at the amounts of Ca(2+) necessary to mediate the functions of mitochondrial Ca(2+) transport and at the mechanisms of transport themselves in order to set up a hypothesis about how the mechanisms carry out their roles. The emphasis here is on isolated mitochondria and on general mitochondrial properties in order to focus on how mitochondria alone may function to fulfill their physiological roles even though the interactions of mitochondria with other organelles, particularly with endoplasmic and sarcoplasmic reticulum [Sci. STKE re1 (2004) 1-9], may also influence this story. 相似文献
85.
Daniela M. Tomazela Gunter Ebeling Marcos N. Eberlin Jairton Dupont 《Inorganica chimica acta》2004,357(8):2349-2357
Electrospray (ESI) mass spectra analysis of acetonitrile solutions of a series of neutral chloro dimers, pincer type, and monomeric palladacycles has enabled the detection of several of their derived ionic species. The monometallic cationic complexes Pd[κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2]+ (1a) and [Pd[κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)]+ (1b) and the bimetallic cationic complex [κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2]Pd-Cl-Pd[κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2]+ (1c) were detected from an acetonitrile solution of the pincer palladacycles Pd[κ1-C,κ1-N,κ1-S-C(CH3S-2-C6H4)C(Cl)CH2N(CH3)2](Cl) 1. For the dimeric compounds {Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](μ-Cl)}2 (2, Y=H and 3, CF3), highly electronically unsaturated palladacycles [Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2]+ (2d, 3d) and their mono and di-acetonitrile adducts, namely, [Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)]+ (2e, 3e) and [Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)2]+ (2f and 3f) were detected together with the bimetallic complex [Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2]-Cl-Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N](CH3)2]+ (2a, 3a) and its acetonitrile adducts [κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)Pd-Cl-Pd[ κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2]+ (2b, 3b) and [κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)Pd-Cl-Pd[κ1-C, κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2(CH3CN)]+ (2c, 3c). The dimeric palladacycle {Pd[κ1-C,κ1-N-C(CH3O-2-C6H4)C(Cl)CH2N(CH3)2](μ-Cl)}2 (4) is unique as it behaves as a pincer type compound with the OCH3 substituent acting as an intramolecular coordinating group which prevents acetonitrile full coordination, thus forming the cationic complexes [(C6H4(o-CH3O)CC(Cl)CH2N(CH3)2-κO,κC,κN)Pd]+ (4b), [(C6H4(o-CH3O)CC(Cl)CH2N(CH3)2- κO,κC,κN)Pd(CH3CN)]+ (4c) and [(C6H4 (o-MeO)CC(Cl)CH2N(CH3)2-κO, κC,κN)Pd-Cl-Pd(C6H4(o-CH3O)CC(Cl)CH2N(CH3)2-κO,κC,κN)]+ (4a). ESI-MS spectra analysis of acetonitrile solutions of the monomeric palladacycles Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](Cl)(Py) (5, Y=H and 6, Y=CF3) allows the detection of some of the same species observed in the spectra of the dimeric palladacycles, i.e., monometallic cationic 2d-3d, 2e-3e and {Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](Py)}+ (5a, 6a) and {Pd[κ1-C,κ1-N-C(Y-2-C6H4)C(Cl)CH2N(CH3)2](CH3CN)(Py)}+ (5b, 6b) and the bimetallic 2a, 3a, 2b, 3b, 2c and 3c. In all cationic complexes detected by ESI-MS, the cyclometallated moiety was intact indicating the high stability of the four or six electron anionic chelate ligands. The anionic (chloride) or neutral (pyridine) ligands are, however, easily replaced by the acetonitrile solvent. 相似文献
86.
Böhm E Sturm GJ Weiglhofer I Sandig H Shichijo M McNamee A Pease JE Kollroser M Peskar BA Heinemann A 《The Journal of biological chemistry》2004,279(9):7663-7670
Thromboxane (TX) A(2), a cyclooxygenase-derived mediator involved in allergic responses, is rapidly converted in vivo to a stable metabolite, 11-dehydro-TXB(2), which is considered to be biologically inactive. In this study, we found that 11-dehydro-TXB(2), but not the TXA(2) analogue U46,619 or TXB(2), activated eosinophils and basophils, as assayed by flow cytometric shape change. 11-Dehydro-TXB(2) was also chemotactic for eosinophils but did not induce, nor inhibit, platelet aggregation. Chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH2) is an important chemoattractant receptor expressed by eosinophils, basophils, and TH2 lymphocytes, and prostaglandin (PG)D(2) has been shown to be its principal ligand. 11-Dehydro-TXB(2) induced calcium flux mainly from intracellular stores in eosinophils, and this response was desensitized after stimulation with PGD(2) but not other eosinophil chemoattractants. Shape change responses of eosinophils and basophils to 11-dehydro-TXB(2) were inhibited by the thromboxane (TP)/CRTH2 receptor antagonist ramatroban, but not the selective TP antagonist SQ29,548, and were insensitive to pertussis toxin. The phospholipase C inhibitor U73,122 attenuated both 11-dehydro-TXB(2)- and PGD(2)-induced shape change. 11-Dehydro-TXB(2) also induced the chemotaxis of BaF/3 cells transfected with hCRTH2 but not naive BaF/3 cells. At a threshold concentration, 11-dehydro-TXB(2) had no antagonistic effect on CRTH2-mediated responses as induced by PGD2. These data show that 11-dehydro-TXB(2) is a full agonist of the CRTH2 receptor and hence might cause CRTH2 activation in cellular contexts where PGD-synthase is not present. Given its production in the allergic lung, antagonism of the 11-dehydro-TXB(2)/CRTH2axis may be of therapeutic relevance. 相似文献
87.
We report on the second case of a reed warbler × great reed warbler hybrid (Acrocephalus scirpaceus and A. arundinaceus). The bird was captured during a standardised ringing session in Belgium in autumn 1999, and fell between the parental species in all measurements. Molecular analyses of two microsatellite loci verified that the bird was a female that had a reed warbler father and a great reed warbler mother. 相似文献
88.
Gunter HE 《Journal of biomechanics》2004,37(7):1119-1124
Vocal fold tissue lesions such as nodules and polyps are thought to develop in response to mechanical stress that occurs during vocal fold collision. Two computational models of vocal fold collision during voice production are used to investigate this hypothesis. A one-dimensional lumped mass model, whose parameters are derived from vocal fold tissue dimensions and material properties, predicts stress perpendicular to the direction of impact (normal stress). A previously published three-dimensional finite element model that incorporates the same dimensions and properties predicts the entire stress tensor. The hypothesis is supported by predictions from the finite element model that three components of normal stress and one component of shear stress are increased during collision in the typical location of lesions (i.e. the center of the superior medial edge of the vocal fold in the middle of the vibrating and contact region). The lumped mass model predicts that mechanical stress is negatively correlated with mucosal thickness (increased by voice warm-up and hydration), is positively correlated with driving force (proportional to voice intensity), and is affected by voice production method. These relationships are consistent with clinical observations of vocal fold lesion risk factors and have implications for improving prevention and treatment of benign vocal fold lesions. 相似文献
89.
Here we describe protocols for preparing and using fluorescent probes that respond to conformational changes by altered Foerster resonance energy transfer (FRET) efficiencies upon phosphorylation or, in principle, other posttranslational modifications (PTMs). The sensor protein, a truncated version of pleckstrin, is sandwiched between short-wavelength-excitation green fluorescent protein (GFP2) and yellow fluorescent protein (EYFP). As a result of complex conformational changes of the protein upon phosphorylation, the introduction of a second PTM consensus sequence bestows sensitivity to a second modification and yields a dual-parameter probe. The first phase of the protocol lays out the cloning strategy for single- and dual-parameter FRET sensors, including the construction of a versatile platform into which different consensus sequences may be inserted to create diverse probes. Protocols for fluorescence microscopy of the probes in living cells and image processing are also described. Probe preparation takes 7 d; microscopy and image processing take 2 h. 相似文献
90.
Aguilar AL Piskol R Beitzinger M Zhu JY Kruspe D Aszodi A Moser M Englert C Meister G 《FEBS letters》2010,584(21):4426-4434
microRNAs (miRNAs) are small non-coding RNAs with fundamental roles in the regulation of gene expression. miRNAs assemble with Argonaute (Ago) proteins to miRNA-protein complexes (miRNPs), which interact with distinct binding sites on mRNAs and regulate gene expression. Specific miRNAs are key regulators of tissue and organ development and it has been shown in mammals that miRNAs are also involved in the pathogenesis of many diseases including cancer. Here, we have characterized the miRNA expression profile of the developing murine genitourinary system. Using a computational approach, we have identified several miRNAs that are specific for the analyzed tissues or the developmental stage. Our comprehensive miRNA expression atlas of the developing genitourinary system forms an invaluable basis for further functional in vivo studies. 相似文献