A host-targeting signal in virulence proteins reveals a secretome in malarial infection     

Hiller NL  Bhattacharjee S  van Ooij C  Liolios K  Harrison T  Lopez-Estraño C  Haldar K 《Science (New York, N.Y.)》2004,306(5703):1934-1937

Malaria parasites secrete proteins across the vacuolar membrane into the erythrocyte, inducing modifications linked to disease and parasite survival. We identified an 11-amino acid signal required for the secretion of proteins from the Plasmodium falciparum vacuole to the human erythrocyte. Bioinformatics predicted a secretome of >320 proteins and conservation of the signal across parasite species. Functional studies indicated the predictive value of the signal and its role in targeting virulence proteins to the erythrocyte and implicated its recognition by a receptor/transporter. Erythrocyte modification by the parasite may involve plasmodial heat shock proteins and be vastly more complex than hitherto realized.  相似文献   

Late Glacial and Postglacial Hudson Bay Sea Episode     

Lee HA 《Science (New York, N.Y.)》1960,131(3413):1609-1611

Geological investigations, archeological studies, and radiocarbon dates indicate a similarity of events around Hudson Bay, commencing at the time Hudson Bay Basin was freed of glacier ice. The sea that then spread around Hudson Bay 7000 to 8000 years ago is here named "Tyrrell Sea." The subsequent rate of land emergence decreased exponentially.  相似文献   

Small-diameter silicon nanowire surfaces     

Ma DD  Lee CS  Au FC  Tong SY  Lee ST 《Science (New York, N.Y.)》2003,299(5614):1874-1877

Small-diameter (1 to 7 nanometers) silicon nanowires (SiNWs) were prepared, and their surfaces were removed of oxide and terminated with hydrogen by a hydrofluoric acid dip. Scanning tunneling microscopy (STM) of these SiNWs, performed both in air and in ultrahigh vacuum, revealed atomically resolved images that can be interpreted as hydrogen-terminated Si (111)-(1 x 1) and Si (001)-(1 x 1) surfaces corresponding to SiH3 on Si (111) and SiH2 on Si (001), respectively. These hydrogen-terminated SiNW surfaces seem to be more oxidation-resistant than regular silicon wafer surfaces, because atomically resolved STM images of SiNWs were obtained in air after several days' exposure to the ambient environment. Scanning tunneling spectroscopy measurements were performed on the oxide-removed SiNWs and were used to evaluate the electronic energy gaps. The energy gaps were found to increase with decreasing SiNW diameter from 1.1 electron volts for 7 nanometers to 3.5 electron volts for 1.3 nanometers, in agreement with previous theoretical predictions.  相似文献   

Post-transcriptional control of class I MHC mRNA expression in adenovirus 12-transformed cells   总被引：17，自引：0，他引：17  

R T Vaessen  A Houweling  A J van der Eb 《Science (New York, N.Y.)》1987,235(4795):1486-1488

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A new type of meteoritic diamond in the enstatite chondrite abee     

Russell SS  Pillinger CT  Arden JW  Lee MR  Ott U 《Science (New York, N.Y.)》1992,256(5054):206-209

Diamonds with delta(13)C values of -2 per mil and less than 50 parts per million (by mass) nitrogen have been isolated from the Abee enstatite chondrite by the same procedure used for concentrating Cdelta, the putative interstellar diamond found ubiquitously in primitive meteorites and characterized by delta(13)C values of -32 to -38 per mil, nitrogen concentrations of 2,000 to 12,500 parts per million, and delta(15)N values of -340 per mil. Because the Abee diamonds have typical solar system isotopic compositions for carbon, nitrogen, and xenon, they are presumably nebular in origin rather than presolar. Their discovery in an unshocked meteorite eliminates the possibility of origins normally invoked to account for diamonds in ureilites and iron meteorites and suggests a low-pressure synthesis. The diamond crystals are approximately 100 nanometers in size, are of an unusual lath shape, and represent approximately 100 parts per million of Abee by mass.  相似文献   

Ultrafiltration Membrane Performance     

van Oss CJ 《Science (New York, N.Y.)》1963,139(3559):1123-1125

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Oxidative damage linked to neurodegeneration by selective alpha-synuclein nitration in synucleinopathy lesions   总被引：2，自引：0，他引：2  

Giasson BI  Duda JE  Murray IV  Chen Q  Souza JM  Hurtig HI  Ischiropoulos H  Trojanowski JQ  Lee VM 《Science (New York, N.Y.)》2000,290(5493):985-989

Aggregated alpha-synuclein proteins form brain lesions that are hallmarks of neurodegenerative synucleinopathies, and oxidative stress has been implicated in the pathogenesis of some of these disorders. Using antibodies to specific nitrated tyrosine residues in alpha-synuclein, we demonstrate extensive and widespread accumulations of nitrated alpha-synuclein in the signature inclusions of Parkinson's disease, dementia with Lewy bodies, the Lewy body variant of Alzheimer's disease, and multiple system atrophy brains. We also show that nitrated alpha-synuclein is present in the major filamentous building blocks of these inclusions, as well as in the insoluble fractions of affected brain regions of synucleinopathies. The selective and specific nitration of alpha-synuclein in these disorders provides evidence to directly link oxidative and nitrative damage to the onset and progression of neurodegenerative synucleinopathies.  相似文献   

Midbody targeting of the ESCRT machinery by a noncanonical coiled coil in CEP55   总被引：1，自引：0，他引：1  

Lee HH  Elia N  Ghirlando R  Lippincott-Schwartz J  Hurley JH 《Science (New York, N.Y.)》2008,322(5901):576-580

The ESCRT (endosomal sorting complex required for transport) machinery is required for the scission of membrane necks in processes including the budding of HIV-1 and cytokinesis. An essential step in cytokinesis is recruitment of the ESCRT-I complex and the ESCRT-associated protein ALIX to the midbody (the structure that tethers two daughter cells) by the protein CEP55. Biochemical experiments show that peptides from ALIX and the ESCRT-I subunit TSG101 compete for binding to the ESCRT and ALIX-binding region (EABR) of CEP55. We solved the crystal structure of EABR bound to an ALIX peptide at a resolution of 2.0 angstroms. The structure shows that EABR forms an aberrant dimeric parallel coiled coil. Bulky and charged residues at the interface of the two central heptad repeats create asymmetry and a single binding site for an ALIX or TSG101 peptide. Both ALIX and ESCRT-I are required for cytokinesis, which suggests that multiple CEP55 dimers are required for function.  相似文献   

Social-ethical issues concerning the control strategy of animal diseases in the European Union: A survey   总被引：1，自引：0，他引：1  

Nina E. Cohen  Marcel A.P.M. van  Asseldonk  Elsbeth N. Stassen 《Agriculture and Human Values》2007,24(4):499-510

In 2004 a survey was conducted in the member states of the European Union designed to gain greater insight into the views on control strategies for foot and mouth disease, classical swine fever, and avian influenza with respect to the epidemiological, economic and social-ethical consequences of each of these animal diseases. This article presents the results of the social-ethical survey. A selection of stakeholders from each member state was asked to prioritize issues for the prevention and control of these diseases. A majority of stakeholders chose preventive measures as the preferred issue. An analysis was done to determine whether there were differences in views expressed by stakeholders from member states with a history of recent epidemics and ones without such a history, and whether there were regional differences. There were no differences between member states with or without a history of recent epidemics. There were indeed regional differences between the priority orders from Northern and Southern Europe on the one hand, and from Eastern Europe on the other. Nina E. Cohen is a biologist and is a researcher at the Wageningen University. She is specialized in societal and ethical issues in human–animal relationships. Her current research is focused on the social-ethical issues concerning the prevention and control of foot and mouth disease, classical swine fever and avian influenza. Marcel A.P.M. van Asseldonk has studied animal science. Currently he works at the Institute for Risk Management in Agriculture (IRMA) of the Wageningen University. He is specialized in the design and pricing of insurance policies and animal health funds for the main livestock epidemics. Elsbeth N. Stassen is a veterinarian and professor of Animals and Society at the Wageningen University. Elsbeth Stassen is specialized in animal health, animal welfare and human–animal relationships. She was a member of a governmental welfare committee during the avian influenza epidemic in the Netherlands in 2003.  相似文献   

Chemically derived, ultrasmooth graphene nanoribbon semiconductors     

Li X  Wang X  Zhang L  Lee S  Dai H 《Science (New York, N.Y.)》2008,319(5867):1229-1232

We developed a chemical route to produce graphene nanoribbons (GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice-defined graphene junctions for potential molecular electronics. The GNRs were solution-phase-derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges with possibly well-defined zigzag or armchair-edge structures. Electrical transport experiments showed that, unlike single-walled carbon nanotubes, all of the sub-10-nanometer GNRs produced were semiconductors and afforded graphene field effect transistors with on-off ratios of about 10(7) at room temperature.  相似文献