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Harroch S Furtado GC Brueck W Rosenbluth J Lafaille J Chao M Buxbaum JD Schlessinger J 《Nature genetics》2002,32(3):411-414
Several lines of evidence suggest that tyrosine phosphorylation is a key element in myelin formation, differentiation of oligodendrocytes and Schwann cells, and recovery from demyelinating lesions. Multiple sclerosis is a demyelinating disease of the human central nervous system, and studies of experimental demyelination indicate that remyelination in vivo requires the local generation, migration or maturation of new oligodendrocytes, or some combination of these. Failure of remyelination in multiple sclerosis could result from the failure of any of these processes or from the death of oligodendrocytes. Ptprz encodes protein tyrosine phosphatase receptor type Z (Ptpz, also designated Rptpbeta), which is expressed primarily in the nervous system but also in oligodendrocytes, astrocytes and neurons. Here we examine the susceptibility of mice deficient in Ptprz to experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. We observe that mice deficient in Ptprz show impaired recovery from EAE induced by myelin oligodendrocyte glycoprotein (MOG) peptide. This sustained paralysis is associated with increased apoptosis of mature oligodendrocytes in the spinal cords of mutant mice at the peak of inflammation. We further demonstrate that expression of PTPRZ1, the human homolog of Ptprz, is induced in multiple sclerosis lesions and that the gene is specifically expressed in remyelinating oligodendrocytes in these lesions. These results support a role for Ptprz in oligodendrocyte survival and in recovery from demyelinating disease. 相似文献
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Annexin II light chain regulates sensory neuron-specific sodium channel expression 总被引:16,自引:0,他引:16
The tetrodotoxin-resistant sodium channel Na(V)1.8/SNS is expressed exclusively in sensory neurons and appears to have an important role in pain pathways. Unlike other sodium channels, Na(V)1.8 is poorly expressed in cell lines even in the presence of accessory beta-subunits. Here we identify annexin II light chain (p11) as a regulatory factor that facilitates the expression of Na(V)1.8. p11 binds directly to the amino terminus of Na(V)1.8 and promotes the translocation of Na(V)1.8 to the plasma membrane, producing functional channels. The endogenous Na(V)1.8 current in sensory neurons is inhibited by antisense downregulation of p11 expression. Because direct association with p11 is required for functional expression of Na(V)1.8, disrupting this interaction may be a useful new approach to downregulating Na(V)1.8 and effecting analgesia. 相似文献
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The atmosphere of Jupiter's satellite Io is extremely tenuous, time variable and spatially heterogeneous. Only a few molecules--SO2, SO and S2--have previously been identified as constituents of this atmosphere, and possible sources include frost sublimation, surface sputtering and active volcanism. Io has been known for almost 30 years to be surrounded by a cloud of Na, which requires an as yet unidentified atmospheric source of sodium. Sodium chloride has been recently proposed as an important atmospheric constituent, based on the detection of chlorine in Io's plasma torus and models of Io's volcanic gases. Here we report the detection of NaCl in Io's atmosphere; it constitutes only approximately 0.3% when averaged over the entire disk, but is probably restricted to smaller regions than SO2 because of its rapid photolysis and surface condensation. Although the inferred abundance of NaCl in volcanic gases is lower than predicted, those volcanic emissions provide an important source of Na and Cl in Io's neutral clouds and plasma torus. 相似文献
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【目的】研究丛枝菌根(Arbuscular mycorrhiza,AM)真菌在喀斯特自然土壤条件下对喀斯特先锋草本植物根系的影响。【方法】通过自然土接种AM真菌(N)、灭菌土接种AM真菌(M)及灭菌土壤对照(S)共3种土壤处理,种植喀斯特先锋植物狗尾草(Setaria viridis)、荩草(Arthraxon hispidus)、鬼针草(Bidens pilosa)及狼杷草(Bidens tripartita),并测定它们的根系生物量、根长、根表面积、根体积、根平均直径、根尖数及根分枝数。【结果】荩草、鬼针草及狼杷草在N处理及M处理下具有较高的菌根侵染率,狗尾草的菌根侵染率较低。与S处理相比,M处理下AM真菌明显提高了荩草、鬼针草及狼杷草的根系生物量、根长、根表面积、根体积、根尖数、根分枝数及组织密度,降低了根平均直径、比根长、比根面积及比根体积;与M处理相比,N处理明显降低了荩草、鬼针草及狼杷草的根系生物量、根长、根表面积、根体积、根尖数、根分枝数及组织密度,提高了比根长、比根面积及比根体积,但对根平均直径无明显影响。【结论】荩草、鬼针草及狼杷草具有较高菌根侵染率,能与AM真菌共生获得更加发达的根系,而自然土壤削弱了AM真菌对荩草、鬼针草及狼杷草根系生长的促进作用。 相似文献
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Banson Kwamina Ewur Asare Daniel Kwasi Dery Fidelis Doodaa Boakye Kwadwo Boniface Akudugu Asamoah Moses Awotwe Lourees Esi 《Systemic Practice and Action Research》2020,33(2):237-264
Systemic Practice and Action Research - Fall armyworm (FAW) infestation in African countries presents significant threats to maize production. Such infestation has major economic implications in... 相似文献
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犹大·福克曼(Judah Folkman)常说:"科学在于你如何想象它"(Science goes where you imagine it).确实,很少有人能像福克曼那样在科学领域如此大胆想象. 相似文献
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This review covers recent findings concerning the specification of the photoreceptor subtypes in the Drosophila eye. Particular attention is paid to aspects of retinal patterning and differentiation where relative timing of events seems to be tightly controlled and essential for proper assembly of the compound eye. For example, specification of the founding photoreceptors of each cluster requires sequential positive and negative signaling through the Notch pathway, and reiterated signaling through the epidermal growth factor receptor leads to the pairwise recruitment of the distinct types of photoreceptors in discrete zones across the eye. Results suggest that different signaling environments for these two receptors may exist across the disc, and that receiving cells may constantly shift their predisposition to respond to such signals by adopting given fates. In addition, considerable data exist that the rate of expansion of retinal patterning across the disc is restricted to allow the orderly patterning of retinal precursors, and that one mechanism for controlling this rate may be the co-ordinated expression anterior to the furrow of factors which both inhibit and promote the expansion of retinal patterning. Finally, this review considers the possibility that the morphogenetic furrow serves as a moving source of morphogens which supply spatial information to both anterior and posterior tissue, providing temporal cues that regulate the many events involved in orderly assembly of the precise array of retinal cell types in the compound eye. 相似文献
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