排序方式: 共有19条查询结果,搜索用时 15 毫秒
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PLETHORA proteins as dose-dependent master regulators of Arabidopsis root development 总被引:1,自引:0,他引:1
Galinha C Hofhuis H Luijten M Willemsen V Blilou I Heidstra R Scheres B 《Nature》2007,449(7165):1053-1057
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Inhibition of growth factor-induced differentiation of PC12 cells by microinjection of antibody to ras p21 总被引:51,自引:0,他引:51
The protein products (p21) of the ras cellular proto-oncogenes are thought to transduce membrane signals necessary for the induction of cell division. However, there is uncertainty as to the precise role of ras p21 in mediating ligand-membrane receptor signals leading to cell differentiation. Treatment of rat phaeochromocytoma cells (PC12) with nerve growth factor (NGF) results in the induction of a number of phenotypic characteristics of sympathetic neurones, including cessation of cell division and outgrowth of neuronal processes (neurites). Here we report that microinjection of antibody to ras p21 into PC12 cells inhibited neurite formation and resulted in temporary regression of partially extended neurites, an effect which was observed up to 36 h after initiation of NGF treatment. Neurite formation induced by cyclic AMP was unaffected by injection of anti-p21 antibody. These results indicate that p21 is involved in the initiation phase of NGF-induced neurite formation in PC12 cells and has a role in hormone-mediated cellular responses distinct from cell proliferation. 相似文献
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Helgadottir A Manolescu A Helgason A Thorleifsson G Thorsteinsdottir U Gudbjartsson DF Gretarsdottir S Magnusson KP Gudmundsson G Hicks A Jonsson T Grant SF Sainz J O'Brien SJ Sveinbjornsdottir S Valdimarsson EM Matthiasson SE Levey AI Abramson JL Reilly MP Vaccarino V Wolfe ML Gudnason V Quyyumi AA Topol EJ Rader DJ Thorgeirsson G Gulcher JR Hakonarson H Kong A Stefansson K 《Nature genetics》2006,38(1):68-74
Variants of the gene ALOX5AP (also known as FLAP) encoding arachidonate 5-lipoxygenase activating protein are known to be associated with risk of myocardial infarction. Here we show that a haplotype (HapK) spanning the LTA4H gene encoding leukotriene A4 hydrolase, a protein in the same biochemical pathway as ALOX5AP, confers modest risk of myocardial infarction in an Icelandic cohort. Measurements of leukotriene B4 (LTB4) production suggest that this risk is mediated through upregulation of the leukotriene pathway. Three cohorts from the United States also show that HapK confers a modest relative risk (1.16) in European Americans, but it confers a threefold larger risk in African Americans. About 27% of the European American controls carried at least one copy of HapK, as compared with only 6% of African American controls. Our analyses indicate that HapK is very rare in Africa and that its occurrence in African Americans is due to European admixture. Interactions with other genetic or environmental risk factors that are more common in African Americans are likely to account for the greater relative risk conferred by HapK in this group. 相似文献
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Riassunto In questo lavoro si descrive una nuova metodica per la determinazione della massa secca dei nuclei delle cellule nervose o gliali mediante il microscopio ad interferenza. Sono riferiti i valori della massa secca, dei volumi e della concentrazione dei nuclei isolati sia da tessuto liofilizzato che da tessuto fresco.
This investigation was supported by a grant to this Department from the Consiglio Nazionale delle Ricerche (No. 04/76/4/3482). 相似文献
This investigation was supported by a grant to this Department from the Consiglio Nazionale delle Ricerche (No. 04/76/4/3482). 相似文献
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Designing models of complex phenomena is a difficult task in engineering that can be tackled by composing a number of partial
models to produce a global model of the phenomena. We propose to embed the partial models in software agents and to implement
their composition as a cooperative negotiation between the agents. The resulting multiagent system provides a global model
of a phenomenon. We applied this approach in modelling two complex physiological processes: the heart rate regulation and
the glucose-insulin metabolism. Beyond the effectiveness demonstrated in these two applications, the idea of using models
associated to software agents to give reason of complex phenomena is in accordance with current tendencies in epistemology,
where it is evident an increasing use of computational models for scientific explanation and analysis. Therefore, our approach
has not only a practical, but also a theoretical significance: agents embedding models are a technology suitable both to representing
and to investigating reality.
相似文献
Francesco AmigoniEmail: |
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Reich D Green RE Kircher M Krause J Patterson N Durand EY Viola B Briggs AW Stenzel U Johnson PL Maricic T Good JM Marques-Bonet T Alkan C Fu Q Mallick S Li H Meyer M Eichler EE Stoneking M Richards M Talamo S Shunkov MV Derevianko AP Hublin JJ Kelso J Slatkin M Pääbo S 《Nature》2010,468(7327):1053-1060
Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4-6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population 'Denisovans' and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans. 相似文献
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The genome of woodland strawberry (Fragaria vesca) 总被引:3,自引:0,他引:3
Shulaev V Sargent DJ Crowhurst RN Mockler TC Folkerts O Delcher AL Jaiswal P Mockaitis K Liston A Mane SP Burns P Davis TM Slovin JP Bassil N Hellens RP Evans C Harkins T Kodira C Desany B Crasta OR Jensen RV Allan AC Michael TP Setubal JC Celton JM Rees DJ Williams KP Holt SH Ruiz Rojas JJ Chatterjee M Liu B Silva H Meisel L Adato A Filichkin SA Troggio M Viola R Ashman TL Wang H Dharmawardhana P Elser J Raja R Priest HD Bryant DW Fox SE Givan SA Wilhelm LJ Naithani S Christoffels A Salama DY 《Nature genetics》2011,43(2):109-116
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Gharavi AG Kiryluk K Choi M Li Y Hou P Xie J Sanna-Cherchi S Men CJ Julian BA Wyatt RJ Novak J He JC Wang H Lv J Zhu L Wang W Wang Z Yasuno K Gunel M Mane S Umlauf S Tikhonova I Beerman I Savoldi S Magistroni R Ghiggeri GM Bodria M Lugani F Ravani P Ponticelli C Allegri L Boscutti G Frasca G Amore A Peruzzi L Coppo R Izzi C Viola BF Prati E Salvadori M Mignani R Gesualdo L Bertinetto F Mesiano P Amoroso A Scolari F Chen N Zhang H Lifton RP 《Nature genetics》2011,43(4):321-327
We carried out a genome-wide association study of IgA nephropathy, a major cause of kidney failure worldwide. We studied 1,194 cases and 902 controls of Chinese Han ancestry, with targeted follow up in Chinese and European cohorts comprising 1,950 cases and 1,920 controls. We identified three independent loci in the major histocompatibility complex, as well as a common deletion of CFHR1 and CFHR3 at chromosome 1q32 and a locus at chromosome 22q12 that each surpassed genome-wide significance (P values for association between 1.59 × 10?2? and 4.84 × 10?? and minor allele odds ratios of 0.63-0.80). These five loci explain 4-7% of the disease variance and up to a tenfold variation in interindividual risk. Many of the alleles that protect against IgA nephropathy impart increased risk for other autoimmune or infectious diseases, and IgA nephropathy risk allele frequencies closely parallel the variation in disease prevalence among Asian, European and African populations, suggesting complex selective pressures. 相似文献