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排序方式: 共有219条查询结果,搜索用时 31 毫秒
21.
Mechelli A Crinion JT Noppeney U O'Doherty J Ashburner J Frackowiak RS Price CJ 《Nature》2004,431(7010):757
Humans have a unique ability to learn more than one language--a skill that is thought to be mediated by functional (rather than structural) plastic changes in the brain. Here we show that learning a second language increases the density of grey matter in the left inferior parietal cortex and that the degree of structural reorganization in this region is modulated by the proficiency attained and the age at acquisition. This relation between grey-matter density and performance may represent a general principle of brain organization. 相似文献
22.
Krakow D Robertson SP King LM Morgan T Sebald ET Bertolotto C Wachsmann-Hogiu S Acuna D Shapiro SS Takafuta T Aftimos S Kim CA Firth H Steiner CE Cormier-Daire V Superti-Furga A Bonafe L Graham JM Grix A Bacino CA Allanson J Bialer MG Lachman RS Rimoin DL Cohn DH 《Nature genetics》2004,36(4):405-410
The filamins are cytoplasmic proteins that regulate the structure and activity of the cytoskeleton by cross-linking actin into three-dimensional networks, linking the cell membrane to the cytoskeleton and serving as scaffolds on which intracellular signaling and protein trafficking pathways are organized (reviewed in refs. 1,2). We identified mutations in the gene encoding filamin B in four human skeletal disorders. We found homozygosity or compound heterozygosity with respect to stop-codon mutations in autosomal recessive spondylocarpotarsal syndrome (SCT, OMIM 272460) and missense mutations in individuals with autosomal dominant Larsen syndrome (OMIM 150250) and the perinatal lethal atelosteogenesis I and III phenotypes (AOI, OMIM 108720; AOIII, OMIM 108721). We found that filamin B is expressed in human growth plate chondrocytes and in the developing vertebral bodies in the mouse. These data indicate an unexpected role in vertebral segmentation, joint formation and endochondral ossification for this ubiquitously expressed cytoskeletal protein. 相似文献
23.
Rab5 is a signalling GTPase involved in actin remodelling by receptor tyrosine kinases 总被引:1,自引:0,他引:1
Rab5 is a small GTPase involved in the control of intracellular trafficking, both at the level of receptor endocytosis and endosomal dynamics. The finding that Rab5 can be activated by receptor tyrosine kinases (RTK) raised the question of whether it also participates in effector pathways emanating from these receptors. Here we show that Rab5 is indispensable for a form of RTK-induced actin remodelling, called circular ruffling. Three independent signals, originating from Rab5, phosphatidylinositol-3-OH kinase and Rac, respectively, are simultaneously required for the induction of circular ruffles. Rab5 signals to the actin cytoskeleton through RN-tre, a previously identified Rab5-specific GTPase-activating protein (GAP). Here we demonstrate that RN-tre has the dual function of Rab5-GAP and Rab5 effector. We also show that RN-tre is critical for macropinocytosis, a process previously connected to the formation of circular ruffles. Finally, RN-tre interacts with both F-actin and actinin-4, an F-actin bundling protein. We propose that RN-tre establishes a three-pronged connection with Rab5, F-actin and actinin-4. This may aid crosslinking of actin fibres into actin networks at the plasma membrane. Thus, we have shown that Rab5 is a signalling GTPase and have elucidated the major molecular elements of its downstream pathway. 相似文献
24.
Diversity-dependent production can decrease the stability of ecosystem functioning 总被引:15,自引:0,他引:15
There is concern that species loss may adversely affect ecosystem functioning and stability. But although there is evidence that biodiversity loss can lead to reductions in biomass production, there is no direct evidence that biodiversity loss affects ecosystem resistance (ability to withstand perturbation) or resilience (recovery from perturbation). Yet theory, laboratory experiments and indirect experimental evidence strongly suggest that diversity and stability are related. Here we report results from a field experiment with factorially crossed perturbation and diversity manipulations. We simulated drought perturbation on constructed grassland ecosystems containing 1, 2, 4, 8 or 32 plant species. Under unperturbed conditions, the species-poor systems achieved lower biomass production than the species-rich systems. However, the species-poor systems were more resistant to perturbation than the species-rich systems. The species-poor systems also showed a larger initial resilience following perturbation, although the original relationship between diversity and productivity was fully restored after 1year. Our results confirm that biodiversity increases biomass production, but they also point to the fact that such diversity--production associations may lead to an inverse relationship between biodiversity and the stability of ecosystem functioning. 相似文献
25.
Haploinsufficiency of ATP1A2 encoding the Na+/K+ pump alpha2 subunit associated with familial hemiplegic migraine type 2 总被引:22,自引:0,他引:22
De Fusco M Marconi R Silvestri L Atorino L Rampoldi L Morgante L Ballabio A Aridon P Casari G 《Nature genetics》2003,33(2):192-196
Headache attacks and autonomic dysfunctions characterize migraine, a very common, disabling disorder with a prevalence of 12% in the general population of Western countries. About 20% of individuals affected with migraine experience aura, a visual or sensory-motor neurological dysfunction that usually precedes or accompanies the headache. Although the mode of transmission is controversial, population-based and twin studies have implicated genetic factors, especially in migraine with aura. Familial hemiplegic migraine is a hereditary form of migraine characterized by aura and some hemiparesis. Here we show that mutations in the gene ATP1A2 that encodes the alpha2 subunit of the Na+/K+ pump are associated with familial hemiplegic migraine type 2 (FHM2) linked to chromosome 1q23 (OMIM 602481). Functional data indicate that the putative pathogenetic mechanism is triggered by a loss of function of a single allele of ATP1A2. This is the first report associating mutations of Na+K+ pump subunits to genetic diseases. 相似文献
26.
Huang E Ishida S Pittman J Dressman H Bild A Kloos M D'Amico M Pestell RG West M Nevins JR 《Nature genetics》2003,34(2):226-230
27.
Robeao Pompoli Andrea Farnetani Nicola Prodi 《华南理工大学学报(自然科学版)》2007,35(B10):5-10
论述了古希腊与古罗马的剧场音质.该研究是由欧共体资助的ERATO项目“古代剧场和表演场所声学遗产的鉴定、评价与振兴”的一部分.该项目对古希腊与古罗马剧场进行了较详尽的调研.文中通过对若干保存得最好的古罗马剧场,如土耳其阿斯彭多斯剧场以及约旦杰拉斯南方剧场测量的脉冲响应进行深入的分析,探讨了其典型构造.同时对西塔库萨剧场建立了1:20的模型,进行了专门的声学测量. 相似文献
28.
Grace W. C. Cheung Andrea Kokorovic Tony K. T. Lam 《Cellular and molecular life sciences : CMLS》2009,66(18):3023-3027
Upon the entry of nutrients into the small intestine, nutrient sensing mechanisms are activated to allow the body to adapt
appropriately to the incoming nutrients. To date, mounting evidence points to the existence of an upper intestinal lipid-induced
gut–brain neuronal axis to regulate energy homeostasis. Moreover, a recent discovery has also revealed an upper intestinal
lipid-induced gut–brain–liver neuronal axis involved in the regulation of glucose homeostasis. In this mini-review, we will
focus on the mechanisms underlying the activation of these respective neuronal axes by upper intestinal lipids. 相似文献
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