Cell biology. Cytonemes show their colors     

Affolter M  Basler K 《Science (New York, N.Y.)》2011,332(6027):312-313

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Axonal neuregulin-1 regulates myelin sheath thickness     

Michailov GV  Sereda MW  Brinkmann BG  Fischer TM  Haug B  Birchmeier C  Role L  Lai C  Schwab MH  Nave KA 《Science (New York, N.Y.)》2004,304(5671):700-703

In the nervous system of vertebrates, myelination is essential for rapid and accurate impulse conduction. Myelin thickness depends on axon fiber size. We use mutant and transgenic mouse lines to show that axonal Neuregulin-1 (Nrg1) signals information about axon size to Schwann cells. Reduced Nrg1 expression causes hypomyelination and reduced nerve conduction velocity. Neuronal overexpression of Nrg1 induces hypermyelination and demonstrates that Nrg1 type III is the responsible isoform. We suggest a model by which myelin-forming Schwann cells integrate axonal Nrg1 signals as a biochemical measure of axon size.  相似文献   

N-linked glycosylation in Campylobacter jejuni and its functional transfer into E. coli     

Wacker M  Linton D  Hitchen PG  Nita-Lazar M  Haslam SM  North SJ  Panico M  Morris HR  Dell A  Wren BW  Aebi M 《Science (New York, N.Y.)》2002,298(5599):1790-1793

N-linked protein glycosylation is the most abundant posttranslation modification of secretory proteins in eukaryotes. A wide range of functions are attributed to glycan structures covalently linked to asparagine residues within the asparagine-X-serine/threonine consensus sequence (Asn-Xaa-Ser/Thr). We found an N-linked glycosylation system in the bacterium Campylobacter jejuni and demonstrate that a functional N-linked glycosylation pathway could be transferred into Escherichia coli. Although the bacterial N-glycan differs structurally from its eukaryotic counterparts, the cloning of a universal N-linked glycosylation cassette in E. coli opens up the possibility of engineering permutations of recombinant glycan structures for research and industrial applications.  相似文献   

E protein silencing by the leukemogenic AML1-ETO fusion protein     

Zhang J  Kalkum M  Yamamura S  Chait BT  Roeder RG 《Science (New York, N.Y.)》2004,305(5688):1286-1289

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Mbeki and AIDS in Africa     

Markus MB  Fincham JE 《Science (New York, N.Y.)》2000,288(5474):2131d

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Germination, genetics, and growth of an ancient date seed     

Sallon S  Solowey E  Cohen Y  Korchinsky R  Egli M  Woodhatch I  Simchoni O  Kislev M 《Science (New York, N.Y.)》2008,320(5882):1464

An ancient date seed (Phoenix dactylifera L.) excavated from Masada and radiocarbon-dated to the first century Common Era was germinated. Climatic conditions at the Dead Sea may have contributed to the longevity of this oldest, directly dated, viable seed. Growth and development of the seedling over 26 months was compatible with normal date seedlings propagated from modern seeds. Preliminary molecular characterization demonstrated high levels of genetic variation in comparison to modern, elite date cultivars currently growing in Israel. As a representative of an extinct date palm population, this seedling can provide insights into the historic date culture of the Dead Sea region. It also has importance for seed banking and conservation and may be of relevance to modern date palm cultivation.  相似文献   

Phylogeny of the SARS coronavirus     

Eickmann M  Becker S  Klenk HD  Doerr HW  Stadler K  Censini S  Guidotti S  Masignani V  Scarselli M  Mora M  Donati C  Han JH  Song HC  Abrignani S  Covacci A  Rappuoli R 《Science (New York, N.Y.)》2003,302(5650):1504-1505

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Cytomegalovirus recruitment of cellular kinases to dissolve the nuclear lamina     

Muranyi W  Haas J  Wagner M  Krohne G  Koszinowski UH 《Science (New York, N.Y.)》2002,297(5582):854-857

The passage of large-sized herpesviral capsids through the nuclear lamina and the inner nuclear membrane to leave the nucleus requires a dissolution of the nuclear lamina. Here, we report on the functions of M50/p35, a beta-herpesviral protein of murine cytomegalovirus. M50/p35 inserts into the inner nuclear membrane and is aggregated by a second viral protein, M53/p38, to form the capsid docking site. M50/p35 recruits the cellular protein kinase C for phosphorylation and dissolution of the nuclear lamina, suggesting that herpesviruses target a critical element of nuclear architecture.  相似文献   

Oxygen Transport     

Markus G 《Science (New York, N.Y.)》1960,132(3419):95-96

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Large magnetic anisotropy of a single atomic spin embedded in a surface molecular network     

Hirjibehedin CF  Lin CY  Otte AF  Ternes M  Lutz CP  Jones BA  Heinrich AJ 《Science (New York, N.Y.)》2007,317(5842):1199-1203

Magnetic anisotropy allows magnets to maintain their direction of magnetization over time. Using a scanning tunneling microscope to observe spin excitations, we determined the orientation and strength of the anisotropies of individual iron and manganese atoms on a thin layer of copper nitride. The relative intensities of the inelastic tunneling processes are consistent with dipolar interactions, as seen for inelastic neutron scattering. First-principles calculations indicate that the magnetic atoms become incorporated into a polar covalent surface molecular network in the copper nitride. These structures, which provide atom-by-atom accessibility via local probes, have the potential for engineering anisotropies large enough to produce stable magnetization at low temperatures for a single atomic spin.  相似文献