What constitutes a proper description?     

Timm RM  Ramey RR;Nomenclature Committee of the American Society of Mammalogists 《Science (New York, N.Y.)》2005,309(5744):2163-6; author reply 2163-6

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"Citizen friendly" science     

Roy R 《Science (New York, N.Y.)》1991,251(4992):362

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Explaining the abundance of ants in lowland tropical rainforest canopies     

Davidson DW  Cook SC  Snelling RR  Chua TH 《Science (New York, N.Y.)》2003,300(5621):969-972

The extraordinary abundance of ants in tropical rainforest canopies has led to speculation that numerous arboreal ant taxa feed principally as "herbivores" of plant and insect exudates. Based on nitrogen (N) isotope ratios of plants, known herbivores, arthropod predators, and ants from Amazonia and Borneo, we find that many arboreal ant species obtain little N through predation and scavenging. Microsymbionts of ants and their hemipteran trophobionts might play key roles in the nutrition of taxa specializing on N-poor exudates. For plants, the combined costs of biotic defenses and herbivory by ants and tended Hemiptera are substantial, and forest losses to insect herbivores vastly exceed current estimates.  相似文献   

A process for controlling intracellular bacterial infections induced by membrane injury     

Roy D  Liston DR  Idone VJ  Di A  Nelson DJ  Pujol C  Bliska JB  Chakrabarti S  Andrews NW 《Science (New York, N.Y.)》2004,304(5676):1515-1518

Strategies for inhibiting phagolysosome fusion are essential for the intracellular survival and replication of many pathogens. We found that the lysosomal synaptotagmin Syt VII is required for a mechanism that promotes phagolysosomal fusion and limits the intracellular growth of pathogenic bacteria. Syt VII was required for a form of Ca2+-dependent phagolysosome fusion that is analogous to Ca2+-regulated exocytosis of lysosomes, which can be triggered by membrane injury. Bacterial type III secretion systems, which permeabilize membranes and cause Ca2+ influx in mammalian cells, promote lysosomal exocytosis and inhibit intracellular survival in Syt VII +/+ but not -/- cells. Thus, the lysosomal repair response can also protect cells against pathogens that trigger membrane permeabilization.  相似文献   

Identification of a DNA nonhomologous end-joining complex in bacteria     

Weller GR  Kysela B  Roy R  Tonkin LM  Scanlan E  Della M  Devine SK  Day JP  Wilkinson A  d'Adda di Fagagna F  Devine KM  Bowater RP  Jeggo PA  Jackson SP  Doherty AJ 《Science (New York, N.Y.)》2002,297(5587):1686-1689

In eukaryotic cells, double-strand breaks (DSBs) in DNA are generally repaired by the pathway of homologous recombination or by DNA nonhomologous end joining (NHEJ). Both pathways have been highly conserved throughout eukaryotic evolution, but no equivalent NHEJ system has been identified in prokaryotes. The NHEJ pathway requires a DNA end-binding component called Ku. We have identified bacterial Ku homologs and show that these proteins retain the biochemical characteristics of the eukaryotic Ku heterodimer. Furthermore, we show that bacterial Ku specifically recruits DNA ligase to DNA ends and stimulates DNA ligation. Loss of these proteins leads to hypersensitivity to ionizing radiation in Bacillus subtilis. These data provide evidence that many bacteria possess a DNA DSB repair apparatus that shares many features with the NHEJ system of eukarya and suggest that this DNA repair pathway arose before the prokaryotic and eukaryotic lineages diverged.  相似文献   

Regulation of cytokine receptors by Golgi N-glycan processing and endocytosis     

Partridge EA  Le Roy C  Di Guglielmo GM  Pawling J  Cheung P  Granovsky M  Nabi IR  Wrana JL  Dennis JW 《Science (New York, N.Y.)》2004,306(5693):120-124

The Golgi enzyme beta1,6 N-acetylglucosaminyltransferase V (Mgat5) is up-regulated in carcinomas and promotes the substitution of N-glycan with poly N-acetyllactosamine, the preferred ligand for galectin-3 (Gal-3). Here, we report that expression of Mgat5 sensitized mouse cells to multiple cytokines. Gal-3 cross-linked Mgat5-modified N-glycans on epidermal growth factor and transforming growth factor-beta receptors at the cell surface and delayed their removal by constitutive endocytosis. Mgat5 expression in mammary carcinoma was rate limiting for cytokine signaling and consequently for epithelial-mesenchymal transition, cell motility, and tumor metastasis. Mgat5 also promoted cytokine-mediated leukocyte signaling, phagocytosis, and extravasation in vivo. Thus, conditional regulation of N-glycan processing drives synchronous modification of cytokine receptors, which balances their surface retention against loss via endocytosis.  相似文献   

Flavonoids from Radix Astragali induce the expression of erythropoietin in cultured cells: a signaling mediated via the accumulation of hypoxia-inducible factor-1α   总被引：1，自引：0，他引：1  

Zheng KY  Choi RC  Cheung AW  Guo AJ  Bi CW  Zhu KY  Fu Q  Du Y  Zhang WL  Zhan JY  Duan R  Lau DT  Dong TT  Tsim KW 《Journal of agricultural and food chemistry》2011,59(5):1697-1704

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Uncommon associations in target resistance among French populations of Myzus persicae from oilseed rape crops     

Fontaine S  Caddoux L  Brazier C  Bertho C  Bertolla P  Micoud A  Roy L 《Pest management science》2011,67(8):881-885

Within the framework of a molecular exploration of target resistance in populations of Myzus persicae on oilseed rapes in France, (1) the S431F mutation (coding gene ace2), although previously reckoned to be rare, revealed to be frequent, (2) M918L (phenotypically characterised) and L932F (both on para) were found for the first time in M. persicae, and (3) a linkage was revealed between M918L and S431F. While until recently populations developing on French oilseed rapes were dominated by genotypes possessing pyrethroid target resistance and esterase overproduction, to date a different type of dominating genotype, equipped with carbamate and pyrethroid target resistance, seems to be invading such fields.  相似文献   

Ion-pair reverse phase liquid chromatographic determination of sodium acifluorfen in feed     

T A Roy  J R Meeks  C R Mackerer 《Journal of the Association of Official Analytical Chemists》1983,66(6):1319-1321

Ion-pair reverse phase liquid chromatography (LC) and UV detection at 280 nm have been used to determine sodium acifluorfen (sodium-5-[2-chloro-4-(trifluoromethyl)-phenoxy]-2-nitrobenzoate), an experimental diphenyl ether herbicide, in dog feed. Sodium-5-(2,4-dichlorophenoxy)-2-nitrobenzoate is used as the internal standard. The feed is homogenized in 0.01N HCl, followed by ethyl acetate extraction, and centrifugation. The organic layer is removed and evaporated and the residue is reconstituted in methanol and filtered before LC analysis (mobile phase methanol-water (58 + 42), 0.005M in tetrabutylammonium phosphate and 0.045M in (NH4)2HPO4, at pH 7.4). The ion-pair technique offers a high degree of control over the retention characteristics of the herbicide and internal standard. The use of the internal standard permits precise and accurate quantitation and substantially reduces analysis time compared with the external standard method.  相似文献   

Feeding preferences of some earthworm species common to upland pastures in Scotland     

Roy Neilson  Brian Boag 《Pedobiologia》2003,47(1):1-8

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