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Based on the biological model of cell-to-cell communication proposed by A. Rustom et al. (Science, 2004, 303: 1007—1010), we investigate the possibilities to apply P systems with dynamic channels transporting membrane vesicles for describing processes in distributed systems. 相似文献
63.
Mikkelsen TS Hanna J Zhang X Ku M Wernig M Schorderet P Bernstein BE Jaenisch R Lander ES Meissner A 《Nature》2008,454(7200):49-55
64.
Meissner A Mikkelsen TS Gu H Wernig M Hanna J Sivachenko A Zhang X Bernstein BE Nusbaum C Jaffe DB Gnirke A Jaenisch R Lander ES 《Nature》2008,454(7205):766-770
DNA methylation is essential for normal development and has been implicated in many pathologies including cancer. Our knowledge about the genome-wide distribution of DNA methylation, how it changes during cellular differentiation and how it relates to histone methylation and other chromatin modifications in mammals remains limited. Here we report the generation and analysis of genome-scale DNA methylation profiles at nucleotide resolution in mammalian cells. Using high-throughput reduced representation bisulphite sequencing and single-molecule-based sequencing, we generated DNA methylation maps covering most CpG islands, and a representative sampling of conserved non-coding elements, transposons and other genomic features, for mouse embryonic stem cells, embryonic-stem-cell-derived and primary neural cells, and eight other primary tissues. Several key findings emerge from the data. First, DNA methylation patterns are better correlated with histone methylation patterns than with the underlying genome sequence context. Second, methylation of CpGs are dynamic epigenetic marks that undergo extensive changes during cellular differentiation, particularly in regulatory regions outside of core promoters. Third, analysis of embryonic-stem-cell-derived and primary cells reveals that 'weak' CpG islands associated with a specific set of developmentally regulated genes undergo aberrant hypermethylation during extended proliferation in vitro, in a pattern reminiscent of that reported in some primary tumours. More generally, the results establish reduced representation bisulphite sequencing as a powerful technology for epigenetic profiling of cell populations relevant to developmental biology, cancer and regenerative medicine. 相似文献
65.
Bencherif M Lippiello PM Lucas R Marrero MB 《Cellular and molecular life sciences : CMLS》2011,68(6):931-949
In recent years the etiopathology of a number of debilitating diseases such as type 2 diabetes, arthritis, atherosclerosis,
psoriasis, asthma, cystic fibrosis, sepsis, and ulcerative colitis has increasingly been linked to runaway cytokine-mediated
inflammation. Cytokine-based therapeutic agents play a major role in the treatment of these diseases. However, the temporospatial
changes in various cytokines are still poorly understood and attempts to date have focused on the inhibition of specific cytokines
such as TNF-α. As an alternative approach, a number of preclinical studies have confirmed the therapeutic potential of targeting
alpha7 nicotinic acetylcholine receptor-mediated anti-inflammatory effects through modulation of proinflammatory cytokines.
This “cholinergic anti-inflammatory pathway” modulates the immune system through cholinergic mechanisms that act on alpha7
receptors expressed on macrophages and immune cells. If the preclinical findings translate into human efficacy this approach
could potentially provide new therapies for treating a broad array of intractable diseases and conditions with inflammatory
components. 相似文献
66.
Rudolf Stenzel 《Annals of science》2013,70(3):289-306
Zunächst wird mit der Entstehung sowie dem Ausbau der beiden Reichsanstalten bis zum Jahre 1922 historisch eingeleitet, wobei über die Reichsanstalt für Mass und Gewicht als die meist unbekanntere etwas ausführlicher berichtet wird. Die Begründungen für oder gegen eine Verschmelzung werden danach aus der Sicht der beiden Reichsanstalten, der Eichbehörden der Länder des Deutschen Reiches, der Industrie, verschiedener Ausschüsse des Deutschen Reichstages und schliesslich der zuständigen Ministerien der Deutschen Reichsregierung angeführt. Mit einem kurzen Blick auf die inflationsbedingten Probleme des deutschen Alltags von Ende 1923 wird der Aufsatz durch eine Beurteilung des vor 53 Jahren geschehenen Zusammenschlusses aus dem Geschehen eben dieser 53 Jahre abgeschlossen. 相似文献
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69.
The majorization method for multidimensional scaling with Kruskal's STRESS has been limited to Euclidean distances only. Here we extend the majorization algorithm to deal with Minkowski distances with 1≤p≤2 and suggest an algorithm that is partially based on majorization forp outside this range. We give some convergence proofs and extend the zero distance theorem of De Leeuw (1984) to Minkowski distances withp>1. 相似文献
70.
Hydrogen is an energy source for hydrothermal vent symbioses 总被引:1,自引:0,他引:1
Petersen JM Zielinski FU Pape T Seifert R Moraru C Amann R Hourdez S Girguis PR Wankel SD Barbe V Pelletier E Fink D Borowski C Bach W Dubilier N 《Nature》2011,476(7359):176-180
The discovery of deep-sea hydrothermal vents in 1977 revolutionized our understanding of the energy sources that fuel primary productivity on Earth. Hydrothermal vent ecosystems are dominated by animals that live in symbiosis with chemosynthetic bacteria. So far, only two energy sources have been shown to power chemosynthetic symbioses: reduced sulphur compounds and methane. Using metagenome sequencing, single-gene fluorescence in situ hybridization, immunohistochemistry, shipboard incubations and in situ mass spectrometry, we show here that the symbionts of the hydrothermal vent mussel Bathymodiolus from the Mid-Atlantic Ridge use hydrogen to power primary production. In addition, we show that the symbionts of Bathymodiolus mussels from Pacific vents have hupL, the key gene for hydrogen oxidation. Furthermore, the symbionts of other vent animals such as the tubeworm Riftia pachyptila and the shrimp Rimicaris exoculata also have hupL. We propose that the ability to use hydrogen as an energy source is widespread in hydrothermal vent symbioses, particularly at sites where hydrogen is abundant. 相似文献