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861.
Risse PA Naline E Faisy C Huchon G Chung KF Kleinmann P Advenier C Roche N 《Life sciences》2004,75(8):991-1002
Protease-activated receptors are G protein-coupled receptors activated by serine-proteases. Protease-activated receptor 2 is involved in the regulation of airway smooth muscle tone but its effects vary according to species and experimental conditions. We determined the effects of protease-activated receptor 2 activation on smooth muscle tone and airway reactivity to histamine in guinea pigs and smoking or non-smoking humans. The effects of trypsin and protease-activated receptor activating peptide on the isometric tension and response to histamine of guinea pig tracheal and human bronchial rings were studied. Human tissues were obtained from 6 smokers and 4 non-smokers. We assessed the effects of epithelial removal, inhibitors of cyclooxygenases, nitric oxide synthases, neutral endopeptidase and antagonists of acetylcholine, histamine, bradykinin and tachykinin receptors. Bronchomotor responses to protease-activated receptor 2 activation were variable in guinea pig, in half of animals PAR2 activation induced smooth muscle relaxation through the epithelial release of prostanoids but not of nitric oxide. In human airways, protease-activated receptor 2 activation reduced responsiveness to histamine in bronchial rings from smokers but increased responsiveness in bronchi from non-smokers. This study demonstrates an influence of tobacco smoking on the effect of protease-activated receptor 2 activation on airway responsiveness in humans, with an increased protection against histamine-induced contractions, probably through an increased epithelial release of prostanoids. The role of airway protease-activated receptor 2 may be to maintain smooth muscle tone homeostasis. 相似文献
862.
Peptide metalloconstructs display interesting conformations, activities, and resistance to proteolysis. However, introduction of a metal core close to the residues that interact with the protein might strongly affect the binding. We investigated the effects of a coordinated oxorhenium core on the binding of model peptides to cyclophilin hCyp-18, a protein implicated in important biological processes and several diseases. For this purpose, we synthesized a series of linear metalloconstructs bearing an oxorhenium(V) core (ReO3+), as well as a peptide cyclized through oxorhenium(V) coordination. All these peptides contain an Ala-Pro-Xaa-pNA moiety (Xaa = Cys derivative) and are anticipated to bind simultaneously to the S1-S1' and S2'-S3' subsites of hCyp-18. Therefore, the metal core is coordinated to both the cysteine residue and exogenous or endogenous NS2 tridentate systems. Cyclization of the peptide through metal coordination did not affect the affinity whereas bimolecular oxorhenium metalloconstructs bind hCyp-18 with a slightly better affinity than the corresponding nonmetalated peptide. Peptide labeling with a 99mTcO3+ core was also carried out successfully. 相似文献
863.
Kambara H Yamada T Tsujioka M Matsunaga S Tanaka R Ali HI Wiart C Yusof M Hassan H Hanifah A Fauzi ZM Mazlan NH Jay M Kunishima M Akaho E 《化学与生物多样性》2006,3(12):1301-1306
As a part of our chemical studies on Malaysian medicinal plants, five Malaysian plant species were evaluated by cytotoxicity assays using P388 murine leukemia cells. Since Acalypha siamensis exhibited the strongest growth inhibition, its constituents were studied as the object of search for bioactive materials. A novel tetraterpene, acalyphaser A (1), was isolated in the course of the purification. Its structure was elucidated on the basis of 1D- and 2D-NMR techniques, and mass spectrometry. 相似文献
864.
With the decreasing cost of DNA sequencing technology and the vast diversity of biological resources, researchers increasingly
face the basic challenge of annotating a larger number of expressed sequences tags (EST) from a variety of species. This typically
consists of a series of repetitive tasks, which should be automated and easy to use. The results of these annotation tasks
need to be stored and organized in a consistent way. All these operations should be self-installing, platform independent,
easy to customize and amenable to using distributed bioinformatics resources available on the Internet. 相似文献
865.
866.
Cynthia Brisac Fran?ois Téoulé Arnaud Autret Isabelle Pelletier Florence Colbère-Garapin Catherine Brenner Christophe Lemaire Bruno Blondel 《Journal of virology》2010,84(23):12226-12235
We show that poliovirus (PV) infection induces an increase in cytosolic calcium (Ca2+) concentration in neuroblastoma IMR5 cells, at least partly through Ca2+ release from the endoplasmic reticulum lumen via the inositol 1,4,5-triphosphate receptor (IP3R) and ryanodine receptor (RyR) channels. This leads to Ca2+ accumulation in mitochondria through the mitochondrial Ca2+ uniporter and the voltage-dependent anion channel (VDAC). This increase in mitochondrial Ca2+ concentration in PV-infected cells leads to mitochondrial dysfunction and apoptosis.Poliovirus (PV), the prototype member of the Picornaviridae family, is the etiological agent of paralytic poliomyelitis (26, 27). This acute human disease of the central nervous system results from the destruction of motor neurons associated with PV replication. In PV-infected mice, motor neurons die through apoptosis (16). However, the mechanisms involved are poorly understood (5).Apoptosis is an active cell death process triggered by various stimuli, including viral infections (18). This process leads to DNA fragmentation and is triggered by two main pathways (22): (i) the extrinsic pathway, mediated by the activation of cell surface death receptors such as Fas/CD95, and (ii) the intrinsic pathway, characterized notably by mitochondrial membrane permeabilization (MMP). In many models, this process implies a loss of mitochondrial transmembrane potential (Δψm) and the release of proapoptotic molecules, including cytochrome c, from the mitochondrial intermembrane space into the cytosol. The apoptotic program initiated by PV infection has been shown to involve mitochondrial dysfunction in several cell lines (2-4, 17).The intrinsic pathway also can originate from the endoplasmic reticulum (ER) (30). The ER participates in protein synthesis and folding, cellular responses to stress, and intracellular calcium (Ca2+) homeostasis. Nevertheless, under stress conditions, it may induce apoptosis via several different mechanisms, one of which involves ER cross-talk with mitochondria, mediated by Ca2+ release from ER stores through the inositol 1,4,5-triphosphate receptor (IP3R) and ryanodine receptor (RyR) channels (7, 12, 15). Several recent studies have identified Ca2+ signaling as a key cellular target for viral infection (for a review, see reference 8). Upon PV infection, cells display an increase in cytosolic Ca2+ concentration (20). Phospholipase C also is activated, leading to an increase in IP3 concentration in PV-infected cells (19), potentially accounting for the observed increase in cytosolic Ca2+ concentration. However, the role of Ca2+ efflux from the ER in PV-induced apoptosis has yet to be studied.Here, we postulated that an increase in cytosolic Ca2+ following PV infection can have an impact on cell fate and investigated the cellular response in terms of mitochondrial function and apoptosis in neuroblastoma IMR5 cells. 相似文献
867.
868.
Senger F Priat C Hitte C Sarropoulou E Franch R Geisler R Bargelloni L Power D Galibert F 《Genomics》2006,87(6):793-800
Among Teleosts, Perciformes are the largest order of fishes and include numerous species of commercial importance. Perciformes also comprise species of primary interest for evolutionary studies and analysis of the sex determination systems and sex chromosome plasticity. Unfortunately, genomics tools and resources for Perciformes remain to be developed. Here, we report the production of a seabream whole-genome radiation hybrid (RH) panel in which quality was ascertained by the construction of a 2-Mb-resolution RH map. The map encompasses 440 markers (288 microsatellites, 82 gene-based markers, and 70 STS) suitable for linkage analysis and comparative mapping studies. Achievement of a RH panel and a whole-genome RH map should contribute to establishing seabream as a fish model among the Perciformes and should be of importance in aquaculture for marker-assisted selection, improvement of growth performance, and disease management. Development of RH maps in a cost-effective manner for other fishes with the described methodology will offer a powerful approach in aquaculture and will provide extended capabilities for comparing vertebrate genome evolution. 相似文献
869.
Christian Cilas Christophe Godin Benoit Bertrand Henri Baillères 《Trees - Structure and Function》2006,20(5):587-592
The physical characteristics of wood are not usually considered as selection criteria when breeding perennial species that are grown for their fruits or seeds. In the coffee tree, stem breakage during harvesting and lodging during the growth period are major defects in some cultivars. These defects are linked to certain physical and mechanical properties of the wood, such as density or rigidity, which can be characterized by a parameter used in the resistance of materials: the Modulus of Elasticity (MOE). Wood density and the longitudinal MOE were studied on the stems of coffee trees of the species Coffee arabica L., derived from a diallel mating design. The MOE was measured by an acoustic system based on an analysis of the vibrations produced by a blow to the end of a piece of wood of known geometry. The MOE obtained in that way, along with the density of coffee tree stem wood, displayed substantial heritability. A strong link between the average internode length and the yield cumulated over 4 years was detected. Wood density was also correlated to yield and wood elasticity. Classification of parents according to the wood characteristics of their progenies depended on their degree of introgression by the species C. canephora. These traits could therefore be used to measure introgression, possibly as predictors of traits of agronomic interest, and as target traits in the creation of tall C. arabica varieties.
相似文献
Christian CilasEmail: Fax: +334-67615581 |
870.