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351.
Abiogenic hydrocarbon production at lost city hydrothermal field 总被引:1,自引:0,他引:1
Proskurowski G Lilley MD Seewald JS Früh-Green GL Olson EJ Lupton JE Sylva SP Kelley DS 《Science (New York, N.Y.)》2008,319(5863):604-607
Low-molecular-weight hydrocarbons in natural hydrothermal fluids have been attributed to abiogenic production by Fischer-Tropsch type (FTT) reactions, although clear evidence for such a process has been elusive. Here, we present concentration, and stable and radiocarbon isotope, data from hydrocarbons dissolved in hydrogen-rich fluids venting at the ultramafic-hosted Lost City Hydrothermal Field. A distinct "inverse" trend in the stable carbon and hydrogen isotopic composition of C1 to C4 hydrocarbons is compatible with FTT genesis. Radiocarbon evidence rules out seawater bicarbonate as the carbon source for FTT reactions, suggesting that a mantle-derived inorganic carbon source is leached from the host rocks. Our findings illustrate that the abiotic synthesis of hydrocarbons in nature may occur in the presence of ultramafic rocks, water, and moderate amounts of heat. 相似文献
352.
Mukhtar MS Carvunis AR Dreze M Epple P Steinbrenner J Moore J Tasan M Galli M Hao T Nishimura MT Pevzner SJ Donovan SE Ghamsari L Santhanam B Romero V Poulin MM Gebreab F Gutierrez BJ Tam S Monachello D Boxem M Harbort CJ McDonald N Gai L Chen H He Y;European Union Effectoromics Consortium Vandenhaute J Roth FP Hill DE Ecker JR Vidal M Beynon J Braun P Dangl JL 《Science (New York, N.Y.)》2011,333(6042):596-601
Plants generate effective responses to infection by recognizing both conserved and variable pathogen-encoded molecules. Pathogens deploy virulence effector proteins into host cells, where they interact physically with host proteins to modulate defense. We generated an interaction network of plant-pathogen effectors from two pathogens spanning the eukaryote-eubacteria divergence, three classes of Arabidopsis immune system proteins, and ~8000 other Arabidopsis proteins. We noted convergence of effectors onto highly interconnected host proteins and indirect, rather than direct, connections between effectors and plant immune receptors. We demonstrated plant immune system functions for 15 of 17 tested host proteins that interact with effectors from both pathogens. Thus, pathogens from different kingdoms deploy independently evolved virulence proteins that interact with a limited set of highly connected cellular hubs to facilitate their diverse life-cycle strategies. 相似文献
353.
354.
Joye SB Leifer I MacDonald IR Chanton JP Meile CD Teske AP Kostka JE Chistoserdova L Coffin R Hollander D Kastner M Montoya JP Rehder G Solomon E Treude T Villareal TA 《Science (New York, N.Y.)》2011,332(6033):1033; author reply 1033
Kessler et al. (Reports, 21 January 2011, p. 312) reported that methane released from the 2010 Deepwater Horizon blowout, approximately 40% of the total hydrocarbon discharge, was consumed quantitatively by methanotrophic bacteria in Gulf of Mexico deep waters over a 4-month period. We find the evidence explicitly linking observed oxygen anomalies to methane consumption ambiguous and extension of these observations to hydrate-derived methane climate forcing premature. 相似文献
355.
Regulation of the germinal center response by microRNA-155 总被引:1,自引:0,他引:1
Thai TH Calado DP Casola S Ansel KM Xiao C Xue Y Murphy A Frendewey D Valenzuela D Kutok JL Schmidt-Supprian M Rajewsky N Yancopoulos G Rao A Rajewsky K 《Science (New York, N.Y.)》2007,316(5824):604-608
MicroRNAs are small RNA species involved in biological control at multiple levels. Using genetic deletion and transgenic approaches, we show that the evolutionarily conserved microRNA-155 (miR-155) has an important role in the mammalian immune system, specifically in regulating T helper cell differentiation and the germinal center reaction to produce an optimal T cell-dependent antibody response. miR-155 exerts this control, at least in part, by regulating cytokine production. These results also suggest that individual microRNAs can exert critical control over mammalian differentiation processes in vivo. 相似文献
356.
Leigh GJ 《Science (New York, N.Y.)》2003,301(5629):55-56
357.
Calarese DA Scanlan CN Zwick MB Deechongkit S Mimura Y Kunert R Zhu P Wormald MR Stanfield RL Roux KH Kelly JW Rudd PM Dwek RA Katinger H Burton DR Wilson IA 《Science (New York, N.Y.)》2003,300(5628):2065-2071
Human antibody 2G12 neutralizes a broad range of human immunodeficiency virus type 1 (HIV-1) isolates by binding an unusually dense cluster of carbohydrate moieties on the "silent" face of the gp120 envelope glycoprotein. Crystal structures of Fab 2G12 and its complexes with the disaccharide Manalpha1-2Man and with the oligosaccharide Man9GlcNAc2 revealed that two Fabs assemble into an interlocked VH domain-swapped dimer. Further biochemical, biophysical, and mutagenesis data strongly support a Fab-dimerized antibody as the prevalent form that recognizes gp120. The extraordinary configuration of this antibody provides an extended surface, with newly described binding sites, for multivalent interaction with a conserved cluster of oligomannose type sugars on the surface of gp120. The unique interdigitation of Fab domains within an antibody uncovers a previously unappreciated mechanism for high-affinity recognition of carbohydrate or other repeating epitopes on cell or microbial surfaces. 相似文献
358.
Culyba EK Price JL Hanson SR Dhar A Wong CH Gruebele M Powers ET Kelly JW 《Science (New York, N.Y.)》2011,331(6017):571-575
N-glycosylation of eukaryotic proteins helps them fold and traverse the cellular secretory pathway and can increase their stability, although the molecular basis for stabilization is poorly understood. Glycosylation of proteins at na?ve sites (ones that normally are not glycosylated) could be useful for therapeutic and research applications but currently results in unpredictable changes to protein stability. We show that placing a phenylalanine residue two or three positions before a glycosylated asparagine in distinct reverse turns facilitates stabilizing interactions between the aromatic side chain and the first N-acetylglucosamine of the glycan. Glycosylating this portable structural module, an enhanced aromatic sequon, in three different proteins stabilizes their native states by -0.7 to -2.0 kilocalories per mole and increases cellular glycosylation efficiency. 相似文献
359.
RG Cashmore TR Harcourt-Brown PM Freeman ND Jeffery N Granger 《Australian veterinary journal》2009,87(1-2):45-50
Three dogs were referred to The Queen's Veterinary School Hospital at University of Cambridge for chronic behavioural or locomotor disorders associated with pain. All three had been unsuccessfully treated with conventional analgesics, including non-steroidal anti-inflammatory drugs, glucocorticoids and opiate agonists, prior to referral, with minimal or no response. They were investigated by neurological examination plus conventional ancillary diagnostic tests and therapeutic drug trials. Ruling out other causes of pain and applying previously well-described criteria, each case was diagnosed as consistent with neuropathic pain, a poorly recognised condition in domestic dogs. Treatment with the tricyclic antidepressant drug, amitriptyline, or the antiepileptic drug, gabapentin, resulted in either a dramatic improvement or full resolution of clinical signs in all cases. 相似文献