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991.
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MAP kinase signalling cascade in Arabidopsis innate immunity 总被引:29,自引:0,他引:29
Asai T Tena G Plotnikova J Willmann MR Chiu WL Gomez-Gomez L Boller T Ausubel FM Sheen J 《Nature》2002,415(6875):977-983
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Alzheimer's and Parkinson's diseases are associated with the formation in the brain of amyloid fibrils from beta-amyloid and alpha-synuclein proteins, respectively. It is likely that oligomeric fibrillization intermediates (protofibrils), rather than the fibrils themselves, are pathogenic, but the mechanism by which they cause neuronal death remains a mystery. We show here that mutant amyloid proteins associated with familial Alzheimer's and Parkinson's diseases form morphologically indistinguishable annular protofibrils that resemble a class of pore-forming bacterial toxins, suggesting that inappropriate membrane permeabilization might be the cause of cell dysfunction and even cell death in amyloid diseases. 相似文献
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DNA points the way ahead in taxonomy 总被引:8,自引:0,他引:8
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A first-generation linkage disequilibrium map of human chromosome 22 总被引:58,自引:0,他引:58
Dawson E Abecasis GR Bumpstead S Chen Y Hunt S Beare DM Pabial J Dibling T Tinsley E Kirby S Carter D Papaspyridonos M Livingstone S Ganske R Lõhmussaar E Zernant J Tõnisson N Remm M Mägi R Puurand T Vilo J Kurg A Rice K Deloukas P Mott R Metspalu A Bentley DR Cardon LR Dunham I 《Nature》2002,418(6897):544-548
DNA sequence variants in specific genes or regions of the human genome are responsible for a variety of phenotypes such as disease risk or variable drug response. These variants can be investigated directly, or through their non-random associations with neighbouring markers (called linkage disequilibrium (LD)). Here we report measurement of LD along the complete sequence of human chromosome 22. Duplicate genotyping and analysis of 1,504 markers in Centre d'Etude du Polymorphisme Humain (CEPH) reference families at a median spacing of 15 kilobases (kb) reveals a highly variable pattern of LD along the chromosome, in which extensive regions of nearly complete LD up to 804 kb in length are interspersed with regions of little or no detectable LD. The LD patterns are replicated in a panel of unrelated UK Caucasians. There is a strong correlation between high LD and low recombination frequency in the extant genetic map, suggesting that historical and contemporary recombination rates are similar. This study demonstrates the feasibility of developing genome-wide maps of LD. 相似文献
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The structure of a sunspot is determined by the local interaction between magnetic fields and convection near the Sun's surface. The dark central umbra is surrounded by a filamentary penumbra, whose complicated fine structure has only recently been revealed by high-resolution observations. The penumbral magnetic field has an intricate and unexpected interlocking-comb structure and some field lines, with associated outflows of gas, dive back down below the solar surface at the outer edge of the spot. These field lines might be expected to float quickly back to the surface because of magnetic buoyancy, but they remain submerged. Here we show that the field lines are kept submerged outside the spot by turbulent, compressible convection, which is dominated by strong, coherent, descending plumes. Moreover, this downward pumping of magnetic flux explains the origin of the interlocking-comb structure of the penumbral magnetic field, and the behaviour of other magnetic features near the sunspot. 相似文献