In vivo determination of the pyridine nucleotide reduction charge by carbon-13 nuclear magnetic resonance spectroscopy     

C J Unkefer  R M Blazer  R E London 《Science (New York, N.Y.)》1983,222(4619):62-65

An intracellular coenzyme has been observed by carbon-13 nuclear magnetic resonance spectroscopy. The pyridine nucleotides in Escherichia coli were specifically labeled with carbon-13 from the biosynthetic precursor, nicotinic acid. The intracellular redox status and metabolic transformations of the pyridine nucleotides were examined under a variety of conditions. A highly reduced nicotinamide adenine dinucleotide pool was observed under anaerobic conditions only in cells that were cultured aerobically on glycerol.  相似文献   

Progression of vertebrate limb development through SHH-mediated counteraction of GLI3     

te Welscher P  Zuniga A  Kuijper S  Drenth T  Goedemans HJ  Meijlink F  Zeller R 《Science (New York, N.Y.)》2002,298(5594):827-830

Distal limb development and specification of digit identities in tetrapods are under the control of a mesenchymal organizer called the polarizing region. Sonic Hedgehog (SHH) is the morphogenetic signal produced by the polarizing region in the posterior limb bud. Ectopic anterior SHH signaling induces digit duplications and has been suspected as a major cause underlying congenital malformations that result in digit polydactyly. Here, we report that the polydactyly of Gli3-deficient mice arises independently of SHH signaling. Disruption of one or both Gli3 alleles in mouse embryos lacking Shh progressively restores limb distal development and digit formation. Our genetic analysis indicates that SHH signaling counteracts GLI3-mediated repression of key regulator genes, cell survival, and distal progression of limb bud development.  相似文献   

Motion to form a quorum     

Park S  Wolanin PM  Yuzbashyan EA  Silberzan P  Stock JB  Austin RH 《Science (New York, N.Y.)》2003,301(5630):188

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A green algal apicoplast ancestor     

Funes S  Davidson E  Reyes-Prieto A  Magallón S  Herion P  King MP  González-Halphen D 《Science (New York, N.Y.)》2002,298(5601):2155

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Coherent two-dimensional nanoscopy     

Aeschlimann M  Brixner T  Fischer A  Kramer C  Melchior P  Pfeiffer W  Schneider C  Strüber C  Tuchscherer P  Voronine DV 《Science (New York, N.Y.)》2011,333(6050):1723-1726

We introduce a spectroscopic method that determines nonlinear quantum mechanical response functions beyond the optical diffraction limit and allows direct imaging of nanoscale coherence. In established coherent two-dimensional (2D) spectroscopy, four-wave-mixing responses are measured using three ingoing waves and one outgoing wave; thus, the method is diffraction-limited in spatial resolution. In coherent 2D nanoscopy, we use four ingoing waves and detect the final state via photoemission electron microscopy, which has 50-nanometer spatial resolution. We recorded local nanospectra from a corrugated silver surface and observed subwavelength 2D line shape variations. Plasmonic phase coherence of localized excitations persisted for about 100 femtoseconds and exhibited coherent beats. The observations are best explained by a model in which coupled oscillators lead to Fano-like resonances in the hybridized dark- and bright-mode response.  相似文献   

Botrytis pseudocinerea, a new cryptic species causing gray mold in French vineyards in sympatry with Botrytis cinerea     

Walker AS  Gautier AL  Confais J  Martinho D  Viaud M  Le P Cheur P  Dupont J  Fournier E 《Phytopathology》2011,101(12):1433-1445

Botrytis cinerea is a major crop pathogen infesting >220 hosts worldwide. A cryptic species has been identified in some French populations but the new species, B. pseudocinerea, has not been fully delimited and established. The aim of this study was to distinguish between the two species, using phylogenetic, biological, morphological, and ecological criteria. Multiple gene genealogies confirmed that the two species belonged to different, well-supported phylogenetic clades. None of the morphological criteria tested (spore size, germination rate, or mycelial growth) was able to discriminate between these two species. Sexual crosses between individuals from the same species and different species were carried out. Only crosses between individuals from the same species were successful. Moreover, population genetics analysis revealed a high level of diversity within each species and a lack of gene flow between them. Finally, a population survey over time showed that B. cinerea was the predominant species but that B. pseudocinerea was more abundant in spring, on floral debris. This observation could not be explained by temperature adaptation in tests carried out in vitro or by aggressiveness on tomato or bean leaves. This study clearly establishes that B. cinerea and B. pseudocinerea constitute a complex of two cryptic species living in sympatry on several hosts, including grapevine and blackberry. We propose several biological or molecular tools for unambiguous differentiation between the two species. B. pseudocinerea probably makes a negligible contribution to gray mold epidemics on grapevine. This new species has been deposited in the MycoBank international database.  相似文献   

Erratum to Variation in aggressiveness of Plasmopara halstedii (sunflower downy mildew).     

Sakr  Nachaat  Ducher  Mireille  Delmotte  Francois  Vear  Felicity  Tourvieille  Jeanne  Walser  Pascal  de Labrouhe  Denis Tourvieille 《植物病害和植物保护杂志》2011,118(3-4):141-141

Journal of Plant Diseases and Protection -  相似文献   

Cd,Cu, Pb and Zn Concentrations in Atmospheric Wet Deposition at a Coastal Station in Western Europe   总被引：1，自引：0，他引：1  

Deboudt  Karine  Flament  Pascal  Bertho  Marie-Laure 《Water, air, and soil pollution》2004,151(1-4):335-359

Water, Air, &; Soil Pollution - Bulk rainfalls were sampled during ten months in the Eastern Channel (Northern France). Chloride and sodium are the heavily loaded major ions in wet deposition,...  相似文献   

Detailed physicochemical characterization of the 2S storage protein from rape (Brassica napus L.)     

Schmidt I  Renard D  Rondeau D  Richomme P  Popineau Y  Axelos MA 《Journal of agricultural and food chemistry》2004,52(19):5995-6001

Chromatographic, chemical, and spectroscopic techniques were used to characterize the physicochemical properties of napin purified by preparative chromatography. The molar extinction coefficient was determined (epsilon = 0.56), and static and dynamic light scattering measurements enabled the average molecular weight (M(w) = 13919), the second virial coefficient (A(2) = 23.95 x 10(-)(5) mol cm(3) g(-)(2)), and the hydrodynamic radius (R(H) = 1.98 nm) to be determined. No conformational changes were observed by fluorescence and circular dichroism measurements in different buffers at pH 3, 4.6, 7, and 12, confirming the high pH stability of this protein. From MALDI-TOF analysis and after enzymatic digestion, it was found that this purified sample, extracted from the rapeseed variety Express, contained mainly isoform 2SS3_BRANA.  相似文献   

Care and Management of Miniature Pet Pigs          下载免费PDF全文

Pascal Dubreuil 《The Canadian veterinary journal. La revue veterinaire canadienne》1995,36(7):452

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