Multicolor and electron microscopic imaging of connexin trafficking     

Gaietta G  Deerinck TJ  Adams SR  Bouwer J  Tour O  Laird DW  Sosinsky GE  Tsien RY  Ellisman MH 《Science (New York, N.Y.)》2002,296(5567):503-507

Recombinant proteins containing tetracysteine tags can be successively labeled in living cells with different colors of biarsenical fluorophores so that older and younger protein molecules can be sharply distinguished by both fluorescence and electron microscopy. Here we used this approach to show that newly synthesized connexin43 was transported predominantly in 100- to 150-nanometer vesicles to the plasma membrane and incorporated at the periphery of existing gap junctions, whereas older connexins were removed from the center of the plaques into pleiomorphic vesicles of widely varying sizes. Selective imaging by correlated optical and electron microscopy of protein molecules of known ages will clarify fundamental processes of protein trafficking in situ.  相似文献   

Disruption of the epithelial apical-junctional complex by Helicobacter pylori CagA     

Amieva MR  Vogelmann R  Covacci A  Tompkins LS  Nelson WJ  Falkow S 《Science (New York, N.Y.)》2003,300(5624):1430-1434

Helicobacter pylori translocates the protein CagA into gastric epithelial cells and has been linked to peptic ulcer disease and gastric carcinoma. We show that injected CagA associates with the epithelial tight-junction scaffolding protein ZO-1 and the transmembrane protein junctional adhesion molecule, causing an ectopic assembly of tight-junction components at sites of bacterial attachment, and altering the composition and function of the apical-junctional complex. Long-term CagA delivery to polarized epithelia caused a disruption of the epithelial barrier function and dysplastic alterations in epithelial cell morphology. CagA appears to target H. pylori to host cell intercellular junctions and to disrupt junction-mediated functions.  相似文献   

Sequence variants in SLITRK1 are associated with Tourette's syndrome   总被引：1，自引：0，他引：1  

Abelson JF  Kwan KY  O'Roak BJ  Baek DY  Stillman AA  Morgan TM  Mathews CA  Pauls DL  Rasin MR  Gunel M  Davis NR  Ercan-Sencicek AG  Guez DH  Spertus JA  Leckman JF  Dure LS  Kurlan R  Singer HS  Gilbert DL  Farhi A  Louvi A  Lifton RP  Sestan N  State MW 《Science (New York, N.Y.)》2005,310(5746):317-320

Tourette's syndrome (TS) is a genetically influenced developmental neuropsychiatric disorder characterized by chronic vocal and motor tics. We studied Slit and Trk-like 1 (SLITRK1) as a candidate gene on chromosome 13q31.1 because of its proximity to a de novo chromosomal inversion in a child with TS. Among 174 unrelated probands, we identified a frameshift mutation and two independent occurrences of the identical variant in the binding site for microRNA hsa-miR-189. These variants were absent from 3600 control chromosomes. SLITRK1 mRNA and hsa-miR-189 showed an overlapping expression pattern in brain regions previously implicated in TS. Wild-type SLITRK1, but not the frameshift mutant, enhanced dendritic growth in primary neuronal cultures. Collectively, these findings support the association of rare SLITRK1 sequence variants with TS.  相似文献   

Paleo-Eskimo mtDNA genome reveals matrilineal discontinuity in Greenland     

Gilbert MT  Kivisild T  Grønnow B  Andersen PK  Metspalu E  Reidla M  Tamm E  Axelsson E  Götherström A  Campos PF  Rasmussen M  Metspalu M  Higham TF  Schwenninger JL  Nathan R  De Hoog CJ  Koch A  Møller LN  Andreasen C  Meldgaard M  Villems R  Bendixen C  Willerslev E 《Science (New York, N.Y.)》2008,320(5884):1787-1789

The Paleo-Eskimo Saqqaq and Independence I cultures, documented from archaeological remains in Northern Canada and Greenland, represent the earliest human expansion into the New World's northern extremes. However, their origin and genetic relationship to later cultures are unknown. We sequenced a mitochondrial genome from a Paleo-Eskimo human by using 3400-to 4500-year-old frozen hair excavated from an early Greenlandic Saqqaq settlement. The sample is distinct from modern Native Americans and Neo-Eskimos, falling within haplogroup D2a1, a group previously observed among modern Aleuts and Siberian Sireniki Yuit. This result suggests that the earliest migrants into the New World's northern extremes derived from populations in the Bering Sea area and were not directly related to Native Americans or the later Neo-Eskimos that replaced them.  相似文献   

Interfering satellite     

Argyle E  Costain CH  Dewdney PE  Galt JA  Landecker T  Roger R 《Science (New York, N.Y.)》1977,197(4306):822

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Radar soundings of the subsurface of Mars   总被引：2，自引：0，他引：2  

Picardi G  Plaut JJ  Biccari D  Bombaci O  Calabrese D  Cartacci M  Cicchetti A  Clifford SM  Edenhofer P  Farrell WM  Federico C  Frigeri A  Gurnett DA  Hagfors T  Heggy E  Herique A  Huff RL  Ivanov AB  Johnson WT  Jordan RL  Kirchner DL  Kofman W  Leuschen CJ  Nielsen E  Orosei R  Pettinelli E  Phillips RJ  Plettemeier D  Safaeinili A  Seu R  Stofan ER  Vannaroni G  Watters TR  Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.  相似文献   

Portrait of Science. Scientist, technologist, proto-feminist, superstar     

Macklis RM 《Science (New York, N.Y.)》2002,295(5560):1647-1648

Although Marie Curie is known primarily for her discovery of radium, her true gift to science was her realization that radioactivity is an intrinsic atomic property of matter rather than the result of chemical processes. She was one of the few Nobel laureates to win the prize twice (physics and chemistry). During her career and as one of the first prominent women scientists, she became increasingly aware of the need for funding for research and of the scientific freedom that money can bring. By nature shy and reserved, Marie's fame, as both a scientist and as an exemplar of a liberated professional woman of the roaring twenties, grew to superstar proportions.  相似文献   

Water Availability for Winter Wheat Affected by Summer Fallow Tillage Practices in Slope Dryland   总被引：2，自引：0，他引：2  

WANG Xiao-bin  CAI Dian-xiong  JIN Ke  WU Hui-jun  BAI Zhan-guo  ZHANG Can-jun  YAO Yu-qing  LU Jun-jie  WANG Yu-hong  YANG Bo  Roger Hartmann  Donald Gabriels 《中国农业科学(英文版)》2003,2(7)

The tillage experiments for winter wheat were conducted on the slope farmland in Luoyang,Henan Province in the semihumid to arid loess plateau areas of North China. Different tillage methods inclu-ding reduced tillage (RT), no-till (NT), 2 crops/year (2C), subsoiling(SS), and conventional tillage (CT)were compared to determine the effects of tillage methods on soil water conservation, water availability, andwheat yields in a search for better farming systems in the areas. The NT and SS showed good effects on waterconservation. The soil water storage increased 12 - 33 mm with NT and 9 - 24 mm with SS at the end of sum-mer fallow periods. The soil evaporation with NT and SS decreased 7 - 8 mm and 34 - 36 mm during the fallowperiods of 1999 and 2001, respectively. Evapotranspiration (ET) with NT and SS increased about 47 mm dur-ing wheat growth periods of 2000 to 2001. Treatment RT and 2C had low water storage and high water lossesduring the fallow periods. The winter wheat yields with conservation tillage practices were improved in the 2ndyear, increased by 3, 5 and 8 % with RT, NT and SS, respectively, compared with CT. The highest wheatyields were obtained with subsoiling, and the maximum economic benefits from no-till. All conservation tillagepractices provided great benefits to saving energy and labors, reducing operation inputs, and increasing eco-nomic returns. No-till and subsoiling have shown promise in increasing water storage, reducing water loss, en-hancing water availability, and saving energy, as well as increasing wheat yield.  相似文献   

Disaster management. Confronting disaster losses     

Bouwer LM  Crompton RP  Faust E  Hoppe P  Pielke RA 《Science (New York, N.Y.)》2007,318(5851):753

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Discovery of olivine in the Nili Fssae region of Mars     

Hoefen TM  Clark RN  Bandfield JL  Smith MD  Pearl JC  Christensen PR 《Science (New York, N.Y.)》2003,302(5645):627-630

We have detected a 30,000-square-kilometer area rich in olivine in the Nili Fossae region of Mars. Nili Fossae has been interpreted as a complex of grabens and fractures related to the formation of the Isidis impact basin. We propose that post-impact faulting of this area has exposed subsurface layers rich in olivine. Linear mixture analysis of Thermal Emission Spectrometer spectra shows surface exposures of 30% olivine, where the composition of the olivine ranges from Fo30 to Fo70.  相似文献