2008 U.S. budget. NSF education program rebounds     

Mervis J 《Science (New York, N.Y.)》2007,315(5813):751

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Human collagenase: identification and characterization of an enzyme from rheumatoid synovium in culture   总被引：23，自引：0，他引：23  

J M Evanson  J J Jeffrey  S M Krane 《Science (New York, N.Y.)》1967,158(800):499-502

Synovial tissue from patients with rheumatoid arthritis produces lysis of gels of reconstituted collagen fibrils in culture and releases soluble collagenase when cultured in collagen-free medium. Collagen molecules in solution at neutral pH at 20 degrees and 27 degrees C are cleaved by the synovial enzyme into (3/4) and (1/4) length fragments. In this respect the action of synovial enzyme is similar to that of amphibian collagenase and distinct from that of bacterial collagenase. At 37 degrees C reconstituted collagen fibrils and native fibers are attacked by the enzyme and further degraded to polypeptides of low molecular weight. These polypeptides are produced only after denaturation of the larger fragments, which occurs at temperatures near 37 degrees C.  相似文献   

Ultrafast flash thermal conductance of molecular chains     

Wang Z  Carter JA  Lagutchev A  Koh YK  Seong NH  Cahill DG  Dlott DD 《Science (New York, N.Y.)》2007,317(5839):787-790

At the level of individual molecules, familiar concepts of heat transport no longer apply. When large amounts of heat are transported through a molecule, a crucial process in molecular electronic devices, energy is carried by discrete molecular vibrational excitations. We studied heat transport through self-assembled monolayers of long-chain hydrocarbon molecules anchored to a gold substrate by ultrafast heating of the gold with a femtosecond laser pulse. When the heat reached the methyl groups at the chain ends, a nonlinear coherent vibrational spectroscopy technique detected the resulting thermally induced disorder. The flow of heat into the chains was limited by the interface conductance. The leading edge of the heat burst traveled ballistically along the chains at a velocity of 1 kilometer per second. The molecular conductance per chain was 50 picowatts per kelvin.  相似文献   

Common sequence variants in the LOXL1 gene confer susceptibility to exfoliation glaucoma     

Thorleifsson G  Magnusson KP  Sulem P  Walters GB  Gudbjartsson DF  Stefansson H  Jonsson T  Jonasdottir A  Jonasdottir A  Stefansdottir G  Masson G  Hardarson GA  Petursson H  Arnarsson A  Motallebipour M  Wallerman O  Wadelius C  Gulcher JR  Thorsteinsdottir U  Kong A  Jonasson F  Stefansson K 《Science (New York, N.Y.)》2007,317(5843):1397-1400

Glaucoma is a leading cause of irreversible blindness. A genome-wide search yielded multiple single-nucleotide polymorphisms (SNPs) in the 15q24.1 region associated with glaucoma. Further investigation revealed that the association is confined to exfoliation glaucoma (XFG). Two nonsynonymous SNPs in exon 1 of the gene LOXL1 explain the association, and the data suggest that they confer risk of XFG mainly through exfoliation syndrome (XFS). About 25% of the general population is homozygous for the highest-risk haplotype, and their risk of suffering from XFG is more than 100 times that of individuals carrying only low-risk haplotypes. The population-attributable risk is more than 99%. The product of LOXL1 catalyzes the formation of elastin fibers found to be a major component of the lesions in XFG.  相似文献   

Education. A new bottom line for school science     

Mervis J 《Science (New York, N.Y.)》2008,319(5866):1030-1033

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THE MUTATION MYTH     

Jeffrey EC 《Science (New York, N.Y.)》1914,39(1005):488-491

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A neoplastic gene fusion mimics trans-splicing of RNAs in normal human cells     

Li H  Wang J  Mor G  Sklar J 《Science (New York, N.Y.)》2008,321(5894):1357-1361

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利用昆虫病原真菌防治贮粮害虫展望     

杰夫·  劳尔德 《安徽农业大学学报》2007,34(2):167-173

Only two fungus species,Beauveria bassiana and Metarhizium anisopliae,have been given serious attention as possible microbial controls for stored-product pests.Their host ranges are broad, but their potency for the various target insects varies greatly,and some of the most important pests such as the red flour beetle are very tolerant of fungi.Accordingly, strategies are needed to improve the fungal performance.One such strategy is combination with other environmentally benign treatments such as controlled desiccant dusts and controlled atmospheres. Ironically the relatively dryness of stored-product environments favors fungal efficacy.Desiccation stress renders some insects more vulnerable to fungi.The longevity of fungus spores is also best under dry conditions.The prospects of fungi for control of stored-product pests can be improved by taking advantage of these phenomena and judicious selection of use venues and application strategies.  相似文献   

Atmospheric sciences. NSF steps over political hurdles to build mobile radar facility     

Mervis J 《Science (New York, N.Y.)》2003,300(5628):2017-2018

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BRCA2 function in DNA binding and recombination from a BRCA2-DSS1-ssDNA structure   总被引：1，自引：0，他引：1  

Yang H  Jeffrey PD  Miller J  Kinnucan E  Sun Y  Thoma NH  Zheng N  Chen PL  Lee WH  Pavletich NP 《Science (New York, N.Y.)》2002,297(5588):1837-1848

Mutations in the BRCA2 (breast cancer susceptibility gene 2) tumor suppressor lead to chromosomal instability due to defects in the repair of double-strand DNA breaks (DSBs) by homologous recombination, but BRCA2's role in this process has been unclear. Here, we present the 3.1 angstrom crystal structure of a approximately 90-kilodalton BRCA2 domain bound to DSS1, which reveals three oligonucleotide-binding (OB) folds and a helix-turn-helix (HTH) motif. We also (i) demonstrate that this BRCA2 domain binds single-stranded DNA, (ii) present its 3.5 angstrom structure bound to oligo(dT)9, (iii) provide data that implicate the HTH motif in dsDNA binding, and (iv) show that BRCA2 stimulates RAD51-mediated recombination in vitro. These findings establish that BRCA2 functions directly in homologous recombination and provide a structural and biochemical basis for understanding the loss of recombination-mediated DSB repair in BRCA2-associated cancers.  相似文献