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排序方式: 共有374条查询结果,搜索用时 15 毫秒
31.
Mreyen M Champion A Srinivasan S Karuso P Williams KL Packer NH 《The Journal of biological chemistry》2000,275(16):12164-12174
A decreased level of fucosylation on certain spore coat proteins of Dictyostelium discoideum alters the permeability of the spore coat. Here the post-translational modifications of a major spore coat protein, SP96, are studied in a wild type strain (X22) and a fucosylation-defective mutant (HU2470). A novel phosphoglycan structure on SP96 of the wild type strain, consisting of Fuc(alpha1-3)GlcNAc-alpha-1-P-Ser(,) was identified by electrospray ionization mass spectrometry and NMR. It was shown using monosaccharide and gas chromatography mass spectrometry analysis that SP96 in the mutant HU2470 contained approximately 20% of wild type levels of fucose, as a result of a missing terminal fucose on the novel glycan structure. The results support previous predictions, based on inhibition studies on different fucose-deficient strains, about the nature of monoclonal antibody epitopes identified by monoclonal antibodies MUD62 and MUD166, which are known to identify O-linked glycans (Champion, A., Griffiths, K., Gooley, A. A., Gonzalez, B. Y., Gritzali, M., West, C. M., and Williams, K. L. (1995) Microbiology 141, 785-797). Quantitative studies on wild type SP96 indicated that there were approximately 60 sites with phosphodiester-linked N-acetylglucosamine-fucose disaccharide units and a further approximately 20 sites with fucose directly linked to the protein. Over 70% of the serine sites are modified, with less than 1% of these sites as phosphoserine. Threonine and tyrosine residues were not found to be modified. 相似文献
32.
ObjectiveThe purpose of the study was to find the potential impact of the sunitinib on the captation of a tracer of the hypoxia, 18F-FMISO, on non tumoral tissues.Population and methodsIt was about a multicentric prospective study on 43 patients with advanced or metastatic renal cancer, treated with Sunitinib. 18F-FMISO PET/CT scan was performed before treatment, followed with a second PET/CT scan after 4 weeks of treatment with sunitinib.ResultsWe have shown a significant increase of FMISO captation under sunitinib in the lungs (p < 0.02) and the liver (p < 0.001). We have also found a significant increase of FMISO captation under antiangiogenic (p < 0.02) of the arterial wall partially calcified among 23/37 patients reached of atherosclerosis, without notable cardiovascular events in the follow-up of these patients. On the other hand, we highlighted a significant reduction of FMISO captation in arthrosic lesions (p < 0.05).Conclusion18F-FMISO PET/CT scan could be a good indicator of the potential toxicities of sunitinib, in particular the pulmonary, hepatic and cardiovascular side effects. It also shows the potential interest of antiangiogenic in inflammatory rheumatic diseases. 相似文献
33.
Bivalacqua TJ Burnett AL Hellstrom WJ Champion HC 《American journal of physiology. Heart and circulatory physiology》2007,292(3):H1340-H1351
Since both increased nitric oxide (NO) synthase (NOS) abundance and diminished NO signaling have been reported in the aging penis, the role of NO in the adaptations of aging remains controversial. Here we tested the hypothesis that arginase, an enzyme that competes with NOS for the substrate l-arginine, contributes to erectile dysfunction with advanced age in the B6/129 mouse strain. Arginase protein abundance, mRNA expression, and enzyme activity were elevated in aged compared with young penile endothelial cells. In addition, endothelial NOS (NOS3) protein abundance was greater in aged versus young penile endothelial cells, whereas NOS activity and cGMP levels were reduced. Calcium-dependent l-arginine-to-l-citrulline conversion and cGMP formation increased significantly in aged mouse penes in the presence of the arginase inhibitor 2(S)-amino-6-boronohexanoic acid (ABH). However, there was no effect on l-arginine-to-l-citrulline conversion or cGMP accumulation in the endothelium from young mouse penes. To assess the functional role of arginase in the inhibition of NOS pathway responsiveness in the penis, we evaluated the effects of ABH and an adeno-associated virus encoding an antisense sequence to arginase I (AAVanti-arginase) on erectile function in vivo. ABH and AAVanti-arginase enhanced endothelium-dependent erectile responses in the aged mice without altering endothelium-independent responses. Paralleling our in vitro observations, ABH or AAVanti-arginase did not affect vascular responses in the young mice. Inhibition of the arginase pathway improves endothelial function in the aging penile circulation, suggesting that the arginase pathway may be exploited to improve erectile dysfunction associated with aging. 相似文献
34.
Philippe Marmey A?da Jalloul Majd Alhamdia Komi Assigbetse Jean-Luc Cacas Andreas E Voloudakis Antony Champion Alain Clerivet Jean-Luc Montillet Michel Nicole 《Plant Physiology and Biochemistry》2007,45(8):596-606
Hypersensitive reaction (HR) cell death of cotton to the incompatible race 18 from Xanthomonas campestris pathovar malvacearum (Xcm) is associated with 9S-lipoxygenase activity (LOX) responsible for lipid peroxidation. Here, we report the cloning of cotton (Gossypium hirsutum L.) LOX gene (GhLOX1) and the sequencing of its promoter. GhLOX1 was found to be highly expressed during Xcm induced HR. Sequence analysis showed that GhLOX1 is a putative 9-LOX, and GhLOX1 promoter contains SA and JA responsive elements. Investigation on LOX signalisation on cotyledons infiltrated with salicylic acid (SA), or incubated with methyl-jasmonate (MeJA) revealed that both treatments induced LOX activity and GhLOX1 gene expression. HR-like symptoms were observed when LOX substrates were then injected in treated (MeJA and SA) cotyledons or when Xcm compatible race 20 was inoculated on MeJA treated cotyledons. Together these results support the fact that GhLOX1 encodes a 9 LOX whose activity would be involved in cell death during cotton HR. 相似文献
35.
36.
Brooke R Snyder Pei-Hsun Cheng Jinjing Yang Shang-Hsun Yang Anderson HC Huang Anthony WS Chan 《BMC cell biology》2011,12(1):1-8
Background
Activation by extracellular ligands of G protein-coupled (GPCRs) and tyrosine kinase receptors (RTKs), results in the generation of second messengers that in turn control specific cell functions. Further, modulation/amplification or inhibition of the initial signalling events, depend on the recruitment onto the plasma membrane of soluble protein effectors. High throughput methodologies to monitor quantitatively second messenger production, have been developed over the last years and are largely used to screen chemical libraries for drug development. On the contrary, no such high throughput methods are yet available for the other aspect of GPCRs regulation, i.e. protein translocation to the plasma membrane, despite the enormous interest of this phenomenon for the modulation of receptor downstream functions. Indeed, to date, the experimental procedures available are either inadequate or complex and expensive.Results
Here we describe the development of a novel conceptual approach to the study of cytosolic proteins translocation to the inner surface of the plasma membrane. The basis of the technique consists in: i) generating chimeras between the protein of interests and the calcium (Ca2+)-sensitive, luminescent photo-protein, aequorin and ii) taking advantage of the large Ca2+ concentration [Ca2+] difference between bulk cytosolic and the sub-plasma membrane rim.Conclusion
This approach, that keeps unaffected the translocation properties of the signalling protein, can in principle be applied to any protein that, upon activation, moves from the cytosol to the plasma membrane. Thus, not only the modulation of GPCRs and RTKs can be investigated in this way, but that of all other proteins that can be recruited to the plasma membrane also independently of receptor activation. Moreover, its automated version, which can provide information about the kinetics and concentration-dependence of the process, is also applicable to high throughput screening of drugs affecting the translocation process. 相似文献37.
Dominique Champion Camille Loupiac Denise Simatos Peter Lillford Philippe Cayot 《Food biophysics》2011,6(1):160-169
The state of water in foodstuffs is a guiding principle in food design, and the equilibrium concept of water activity (Aw)
is ubiquitous. It is regarded as a primary variable or “hurdle” in preservation technology, and a key variable influencing
chemical reaction during storage. However, the amount of water in any system differs as function of water activity depending
whether it is determined by water sorption or desorption. Even though this hysteresis behaviour has already been described
in the literature, no physical interpretation of its origin has yet been proposed with respect to detailed molecular organisation.
This work shows, for two different food powders, gluten and a milk-based product that the hysteresis disappears when either
go through their glass transition. A more complete DSC analysis for gluten during different sorption/desorption cycles demonstrates
that the hysteresis is dependent on the ageing of the material, which evolves in the glassy state and is induced by structural
relaxation. 相似文献
38.
Champion M 《Molecular cell》2005,17(4):475-477
Recent studies have established that the eukaryotic actin-based cytoskeleton has prokaryotic origins. In addition to regulating cell shape and polarity, Gitai et al. (2005) provide convincing evidence that the Caulobacter actin homolog MreB also mediates the early segregation of the chromosomal origin, a typical functional role of the eukaryotic tubulin-based cytoskeleton. 相似文献
39.
40.
Effects of successive seasons of genetically modified herbicide-tolerant maize cropping on weeds and invertebrates 总被引:1,自引:0,他引:1
M.S. Heard S.J. Clark P. Rothery J.N. Perry D.A. Bohan D.R. Brooks G.T. Champion A.M. Dewar C. Hawes A.J. Haughton M.J. May R.J. Scott R.S. Stuart G.R. Squire & L.G. Firbank 《The Annals of applied biology》2006,149(3):249-254
The use of genetically modified herbicide‐tolerant (GMHT) crops influences the abundance of weeds and some invertebrate groups because the associated herbicide regime contrasts with that of conventional systems. However, it is not clear to what extent these effects might be cumulative; should GMHT crops be grown continuously. In northern Europe, in the near future, this situation is most likely to apply to maize crops. Here, we consider the effects of continuous GMHT maize cropping on plant and invertebrate taxa using a split‐field experiment. Half of each field was managed using GMHT and the other half with a conventional variety, with the treatments retained for two seasons. The treatment effects were broadly consistent with those found in the larger sample of non‐continuous maize sites within the Farm Scale Evaluations. There was little evidence of effects being significantly more pronounced in the second year; any cumulative differences in above‐ground biodiversity between GMHT and conventional cropping were too variable to be readily detected. 相似文献