Science

Phosphatidic acid is a pH biosensor that links membrane biogenesis to metabolism.

Publication Date: 2010 Aug 27 PMID: 20798321
Authors: Young, B. P. - Shin, J. J. - Orij, R. - Chao, J. T. - Li, S. C. - Guan, X. L. - Khong, A. - Jan, E. - Wenk, M. R. - Prinz, W. A. - Smits, G. J. - Loewen, C. J.
Journal: Science

Recognition of lipids by proteins is important for their targeting and activation in many signaling pathways, but the mechanisms that regulate such interactions are largely unknown. Here, we found that binding of proteins to the ubiquitous signaling lipid phosphatidic acid (PA) depended on intracellular pH and the protonation state of its phosphate headgroup. In yeast, a rapid decrease in intracellular pH in response to glucose starvation regulated binding of PA to a transcription factor, Opi1, that coordinately repressed phospholipid metabolic genes. This enabled coupling of membrane biogenesis to nutrient availability.

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Optimally interacting minds.

Publication Date: 2010 Aug 27 PMID: 20798320
Authors: Bahrami, B. - Olsen, K. - Latham, P. E. - Roepstorff, A. - Rees, G. - Frith, C. D.
Journal: Science

In everyday life, many people believe that two heads are better than one. Our ability to solve problems together appears to be fundamental to the current dominance and future survival of the human species. But are two heads really better than one? We addressed this question in the context of a collective low-level perceptual decision-making task. For two observers of nearly equal visual sensitivity, two heads were definitely better than one, provided they were given the opportunity to communicate freely, even in the absence of any feedback about decision outcomes. But for observers with very different visual sensitivities, two heads were actually worse than the better one. These seemingly discrepant patterns of group behavior can be explained by a model in which two heads are Bayes optimal under the assumption that individuals accurately communicate their level of confidence on every trial.

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Insects betray themselves in nature to predators by rapid isomerization of green leaf volatiles.

Publication Date: 2010 Aug 27 PMID: 20798319
Authors: Allmann, S. - Baldwin, I. T.
Journal: Science

Plants emit green leaf volatiles (GLVs) in response to herbivore damage, thereby attracting predators of the herbivores as part of an indirect defense. The GLV component of this indirect defense was thought to be a general wound signal lacking herbivore-specific information. We found that Manduca sexta-infested Nicotiana attenuata attract the generalist hemipteran predator Geocoris spp. as the result of an herbivore-induced decrease in the (Z)/(E) ratio of released GLVs, and that these changes in the volatile bouquet triple the foraging efficiency of predators in nature. These (E)-isomers are produced from plant-derived (Z)-isomers but are converted by a heat-labile constituent of herbivore oral secretions. Hence, attacking herbivores initiate the release of an indirect defense a full day before the attacked plants manufacture their own defensive compounds.

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Crystal structure of human adenovirus at 3.5 A resolution.

Publication Date: 2010 Aug 27 PMID: 20798318
Authors: Reddy, V. S. - Natchiar, S. K. - Stewart, P. L. - Nemerow, G. R.
Journal: Science

Rational development of adenovirus vectors for therapeutic gene transfer is hampered by the lack of accurate structural information. Here, we report the x-ray structure at 3.5 angstrom resolution of the 150-megadalton adenovirus capsid containing nearly 1 million amino acids. We describe interactions between the major capsid protein (hexon) and several accessory molecules that stabilize the capsid. The virus structure also reveals an altered association between the penton base and the trimeric fiber protein, perhaps reflecting an early event in cell entry. The high-resolution structure provides a substantial advance toward understanding the assembly and cell entry mechanisms of a large double-stranded DNA virus and provides new opportunities for improving adenovirus-mediated gene transfer.

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Genomic comparison of the ants Camponotus floridanus and Harpegnathos saltator.

Publication Date: 2010 Aug 27 PMID: 20798317
Authors: Bonasio, R. - Zhang, G. - Ye, C. - Mutti, N. S. - Fang, X. - Qin, N. - Donahue, G. - Yang, P. - Li, Q. - Li, C. - Zhang, P. - Huang, Z. - Berger, S. L. - Reinberg, D. - Wang, J. - Liebig, J.
Journal: Science

The organized societies of ants include short-lived worker castes displaying specialized behavior and morphology and long-lived queens dedicated to reproduction. We sequenced and compared the genomes of two socially divergent ant species: Camponotus floridanus and Harpegnathos saltator. Both genomes contained high amounts of CpG, despite the presence of DNA methylation, which in non-Hymenoptera correlates with CpG depletion. Comparison of gene expression in different castes identified up-regulation of telomerase and sirtuin deacetylases in longer-lived H. saltator reproductives, caste-specific expression of microRNAs and SMYD histone methyltransferases, and differential regulation of genes implicated in neuronal function and chemical communication. Our findings provide clues on the molecular differences between castes in these two ants and establish a new experimental model to study epigenetics in aging and behavior.

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Secreted peptide signals required for maintenance of root stem cell niche in Arabidopsis.

Publication Date: 2010 Aug 27 PMID: 20798316
Authors: Matsuzaki, Y. - Ogawa-Ohnishi, M. - Mori, A. - Matsubayashi, Y.
Journal: Science

Stem cells are maintained in the niche by intercellular interactions and signaling networks. In this work, we study extracellular signals required for maintenance of the root stem cell niche in higher plants. We identify a family of functionally redundant homologous peptides that are secreted, tyrosine-sulfated, and expressed mainly in the stem cell area and the innermost layer of central columella cells. We name these peptides root meristem growth factors (RGFs). RGFs are required for maintenance of the root stem cell niche and transit amplifying cell proliferation in Arabidopsis. RGF1 defines expression levels and patterns of the stem cell transcription factor PLETHORA, mainly at the posttranscriptional level. The RGFs function independently of the auxin pathway. These peptide signals play a crucial role in postembryonic root development.

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Trapping a diradical transition state by mechanochemical polymer extension.

Publication Date: 2010 Aug 27 PMID: 20798315
Authors: Lenhardt, J. M. - Ong, M. T. - Choe, R. - Evenhuis, C. R. - Martinez, T. J. - Craig, S. L.
Journal: Science

Transition state structures are central to the rates and outcomes of chemical reactions, but their fleeting existence often leaves their properties to be inferred rather than observed. By treating polybutadiene with a difluorocarbene source, we embedded gem-difluorocyclopropanes (gDFCs) along the polymer backbone. We report that mechanochemical activation of the polymer under tension opens the gDFCs and traps a 1,3-diradical that is formally a transition state in their stress-free electrocyclic isomerization. The trapped diradical lives long enough that we can observe its noncanonical participation in bimolecular addition reactions. Furthermore, the application of a transient tensile force induces a net isomerization of the trans-gDFC into its less-stable cis isomer, leading to the counterintuitive result that the gDFC contracts in response to a transient force of extension.

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An adaptable peptide-based porous material.

Publication Date: 2010 Aug 27 PMID: 20798314
Authors: Rabone, J. - Yue, Y. F. - Chong, S. Y. - Stylianou, K. C. - Bacsa, J. - Bradshaw, D. - Darling, G. R. - Berry, N. G. - Khimyak, Y. Z. - Ganin, A. Y. - Wiper, P. - Claridge, J. B. - Rosseinsky, M. J.
Journal: Science

Porous materials find widespread application in storage, separation, and catalytic technologies. We report a crystalline porous solid with adaptable porosity, in which a simple dipeptide linker is arranged in a regular array by coordination to metal centers. Experiments reinforced by molecular dynamics simulations showed that low-energy torsions and displacements of the peptides enabled the available pore volume to evolve smoothly from zero as the guest loading increased. The observed cooperative feedback in sorption isotherms resembled the response of proteins undergoing conformational selection, suggesting an energy landscape similar to that required for protein folding. The flexible peptide linker was shown to play the pivotal role in changing the pore conformation.

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Dynamical instability produces transform faults at mid-ocean ridges.

Publication Date: 2010 Aug 27 PMID: 20798313
Authors: Gerya, T.
Journal: Science

Transform faults at mid-ocean ridges--one of the most striking, yet enigmatic features of terrestrial plate tectonics--are considered to be the inherited product of preexisting fault structures. Ridge offsets along these faults therefore should remain constant with time. Here, numerical models suggest that transform faults are actively developing and result from dynamical instability of constructive plate boundaries, irrespective of previous structure. Boundary instability from asymmetric plate growth can spontaneously start in alternate directions along successive ridge sections; the resultant curved ridges become transform faults within a few million years. Fracture-related rheological weakening stabilizes ridge-parallel detachment faults. Offsets along the transform faults change continuously with time by asymmetric plate growth and discontinuously by ridge jumps.

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Atomic structure of human adenovirus by cryo-EM reveals interactions among protein networks.

Publication Date: 2010 Aug 27 PMID: 20798312
Authors: Liu, H. - Jin, L. - Koh, S. B. - Atanasov, I. - Schein, S. - Wu, L. - Zhou, Z. H.
Journal: Science

Construction of a complex virus may involve a hierarchy of assembly elements. Here, we report the structure of the whole human adenovirus virion at 3.6 angstroms resolution by cryo-electron microscopy (cryo-EM), revealing in situ atomic models of three minor capsid proteins (IIIa, VIII, and IX), extensions of the (penton base and hexon) major capsid proteins, and interactions within three protein-protein networks. One network is mediated by protein IIIa at the vertices, within group-of-six (GOS) tiles--a penton base and its five surrounding hexons. Another is mediated by ropes (protein IX) that lash hexons together to form group-of-nine (GON) tiles and bind GONs to GONs. The third, mediated by IIIa and VIII, binds each GOS to five surrounding GONs. Optimization of adenovirus for cancer and gene therapy could target these networks.

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The dynamics of plate tectonics and mantle flow: from local to global scales.

Publication Date: 2010 Aug 27 PMID: 20798311
Authors: Stadler, G. - Gurnis, M. - Burstedde, C. - Wilcox, L. C. - Alisic, L. - Ghattas, O.
Journal: Science

Plate tectonics is regulated by driving and resisting forces concentrated at plate boundaries, but observationally constrained high-resolution models of global mantle flow remain a computational challenge. We capitalized on advances in adaptive mesh refinement algorithms on parallel computers to simulate global mantle flow by incorporating plate motions, with individual plate margins resolved down to a scale of 1 kilometer. Back-arc extension and slab rollback are emergent consequences of slab descent in the upper mantle. Cold thermal anomalies within the lower mantle couple into oceanic plates through narrow high-viscosity slabs, altering the velocity of oceanic plates. Viscous dissipation within the bending lithosphere at trenches amounts to approximately 5 to 20% of the total dissipation through the entire lithosphere and mantle.

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CoRoT reveals a magnetic activity cycle in a Sun-like star.

Publication Date: 2010 Aug 27 PMID: 20798310
Authors: Garcia, R. A. - Mathur, S. - Salabert, D. - Ballot, J. - Regulo, C. - Metcalfe, T. S. - Baglin, A.
Journal: Science

The 11-year activity cycle of the Sun is a consequence of a dynamo process occurring beneath its surface. We analyzed photometric data obtained by the CoRoT space mission, showing solarlike oscillations in the star HD49933, for signatures of stellar magnetic activity. Asteroseismic measurements of global changes in the oscillation frequencies and mode amplitudes reveal a modulation of at least 120 days, with the minimum frequency shift corresponding to maximum amplitude as in the Sun. These observations are evidence of a stellar magnetic activity cycle taking place beneath the surface of HD49933 and provide constraints for stellar dynamo models under conditions different from those of the Sun.

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SPORE series winner. The universe online.

Publication Date: 2010 Aug 27 PMID: 20798309
Authors: Raddick, M. J. - Szalay, A. S.
Journal: Science

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Virology. Looking inside adenovirus.

Publication Date: 2010 Aug 27 PMID: 20798308
Authors: Harrison, S. C.
Journal: Science

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Chemistry. Opening the door to peptide-based porous solids.

Publication Date: 2010 Aug 27 PMID: 20798307
Authors: Wright, P. A.
Journal: Science

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Developmental biology. Microenvironment mimicry.

Publication Date: 2010 Aug 27 PMID: 20798306
Authors: Bhatia, M.
Journal: Science

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Behavior. Decisions made better.

Publication Date: 2010 Aug 27 PMID: 20798305
Authors: Ernst, M. O.
Journal: Science

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Immunology. Prime, boost, and broaden.

Publication Date: 2010 Aug 27 PMID: 20798304
Authors: Doms, R. W.
Journal: Science

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Geophysics. Fine-scale modeling of global plate tectonics.

Publication Date: 2010 Aug 27 PMID: 20798303
Authors: Becker, T.
Journal: Science

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Disasters. Scenario-building for the Deepwater Horizon oil spill.

Publication Date: 2010 Aug 27 PMID: 20798302
Authors: Machlis, G. E. - McNutt, M. K.
Journal: Science

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Dietary restriction: theory fails to satiate.

Publication Date: 2010 Aug 27 PMID: 20798300
Authors: Hayflick, L.
Journal: Science

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Comment on "A southern tyrant reptile".

Publication Date: 2010 Aug 27 PMID: 20798297
Authors: Herne, M. C. - Nair, J. P. - Salisbury, S. W.
Journal: Science

Benson et al. (Brevia, 26 March 2010, p. 1613) reported on an Australian tyrannosauroid, represented by a pubis from the late Early Cretaceous of Victoria. However, our examination of this specimen reveals that the critical character used for this referral is not present. We contend that the bone likely belongs to a currently recognized group of Australian theropod or another group not currently known.

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Dietary restriction: standing up for sirtuins.

Publication Date: 2010 Aug 27 PMID: 20798296
Authors: Baur, J. A. - Chen, D. - Chini, E. N. - Chua, K. - Cohen, H. Y. - de Cabo, R. - Deng, C. - Dimmeler, S. - Gius, D. - Guarente, L. P. - Helfand, S. L. - Imai, S. - Itoh, H. - Kadowaki, T. - Koya, D. - Leeuwenburgh, C. - McBurney, M. - Nabeshima, Y. - Neri, C. - Oberdoerffer, P. - Pestell, R. G. - Rogina, B. - Sadoshima, J. - Sartorelli, V. - Serrano, M. - Sinclair, D. A. - Steegborn, C. - Tatar, M. - Tissenbaum, H. A. - Tong, Q. - Tsubota, K. - Vaquero, A. - Verdin, E.
Journal: Science

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Infectious disease. From pigs to people: the emergence of a new superbug.

Publication Date: 2010 Aug 27 PMID: 20798295
Authors: Ferber, D.
Journal: Science

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Archaeology. Google Earth shows clandestine worlds.

Publication Date: 2010 Aug 27 PMID: 20798294
Authors: Pringle, H.
Journal: Science

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Chemistry. Organizers panned for omitting Israelis from meeting in Jordan.

Publication Date: 2010 Aug 27 PMID: 20798292
Authors: Service, R. F.
Journal: Science

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U.S. science policy. NSF turns math earmark on its ear to fund new institute.

Publication Date: 2010 Aug 27 PMID: 20798291
Authors: Mervis, J.
Journal: Science

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Cell biology. To scientists' dismay, mixed-up cell lines strike again.

Publication Date: 2010 Aug 27 PMID: 20798289
Authors: Vogel, G.
Journal: Science

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Research facilities. U.S. physicists eye Australia for new site of gravitational-wave detector.

Publication Date: 2010 Aug 27 PMID: 20798288
Authors: Cho, A.
Journal: Science

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China. Astronomers hope their prize telescope isn't blinded by the light.

Publication Date: 2010 Aug 27 PMID: 20798287
Authors: Stone, R.
Journal: Science

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Marine ecology. Hard summer for corals kindles fears for survival of reefs.

Publication Date: 2010 Aug 27 PMID: 20798286
Authors: Normile, D.
Journal: Science

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Chronic fatigue syndrome. New XMRV paper looks good, skeptics admit--yet doubts linger.

Publication Date: 2010 Aug 27 PMID: 20798285
Authors: Enserink, M.
Journal: Science

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What is STEM education?

Publication Date: 2010 Aug 27 PMID: 20798284
Authors: Bybee, R. W.
Journal: Science

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Kepler-9: A System of Multiple Planets Transiting a Sun-Like Star, Confirmed by Timing Variations.

Publication Date: 2010 Aug 26 PMID: 20798283
Authors: Holman, M. J. - Fabrycky, D. C. - Ragozzine, D. - Ford, E. B. - Steffen, J. H. - Welsh, W. F. - Lissauer, J. J. - Latham, D. W. - Marcy, G. W. - Walkowicz, L. M. - Batalha, N. M. - Jenkins, J. M. - Rowe, J. F. - Cochran, W. D. - Fressin, F. - Torres, G. - Buchhave, L. A. - Sasselov, D. D. - Borucki, W. J. - Koch, D. G. - Basri, G. - Brown, T. M. - Caldwell, D. A. - Charbonneau, D. - Dunham, E. W. - Gautier, T. N. 3rd - Geary, J. C. - Gilliland, R. L. - Haas, M. R. - Howell, S. B. - Ciardi, D. R. - Endl, M. - Fischer, D. - Furesz, G. - Hartman, J. D. - Isaacson, H. - Johnson, J. A. - Macqueen, P. J. - Moorhead, A. V. - Morehead, R. C. - Orosz, J. A.
Journal: Science

The Kepler spacecraft is monitoring over 150,000 stars for evidence of planets transiting those stars. We report the detection, based on 7 months of Kepler observations, of two Saturn-size planets that transit the same Sun-like star. Their 19.2- and 38.9-day periods are presently increasing and decreasing at respective average rates of 4 and 39 min per orbit, and in addition the transit times of the inner body display an alternating variation of smaller amplitude. These signatures are characteristic of gravitational interaction of two planets near a 2:1 orbital resonance. Six radial velocity observations show that these two planets are the most massive objects orbiting close to the star and substantially improve the estimates of their masses. After removing the signal of the two con fi rmed giant planets, we identify an additional transiting super-Earth-size planet candidate with a period of 1.6 days.

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{alpha}-Synuclein Promotes SNARE-Complex Assembly in Vivo and in Vitro.

Publication Date: 2010 Aug 26 PMID: 20798282
Authors: Burre, J. - Sharma, M. - Tsetsenis, T. - Buchman, V. - Etherton, M. - Sudhof, T. C.
Journal: Science

Presynaptic nerve terminals release neurotransmitters repeatedly, often at high frequency, and in relative isolation from neuronal cell bodies. Repeated release requires cycles of SNARE-complex assembly and disassembly, with continuous generation of reactive SNARE-protein intermediates. Although many forms of neurodegeneration initiate presynaptically, only few pathogenic mechanisms are known, and the functions of presynaptic proteins linked to neurodegeneration, such as alpha-synuclein, remain unclear. Here, we find that maintenance of continuous presynaptic SNARE-complex assembly required a nonclassical chaperone activity mediated by synucleins. Specifically, alpha-synuclein directly bound to the SNARE-protein synaptobrevin-2/VAMP2 and promoted SNARE-complex assembly. Moreover, triple knockout mice lacking synucleins developed age-dependent neurological impairments, exhibited decreased SNARE-complex assembly, and perished prematurely. Thus, synucleins may function to sustain normal SNARE-complex assembly in a presynaptic terminal during aging.

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Freezing Tolerance in Plants Requires Lipid Remodeling at the Outer Chloroplast Membrane.

Publication Date: 2010 Aug 26 PMID: 20798281
Authors: Moellering, E. R. - Muthan, B. - Benning, C.
Journal: Science

Plants show complex adaptations to freezing that prevent cell damage due to cellular dehydration. Lipid remodeling of cell membranes during dehydration is one critical mechanism countering loss of membrane integrity and cell death. SENSITIVE TO FREEZING 2 (SFR2), a gene essential for freezing tolerance in Arabidopsis , encodes a galactolipid remodeling enzyme of the outer chloroplast envelope membrane. SFR2 processively transfers galactosyl residues from the abundant monogalactolipid to different galactolipid acceptors forming oligogalactolipids and diacylglycerol, which is further converted to triacylglycerol. The combined activity of SFR2 and triacylglycerol-biosynthetic enzymes leads to the removal of monogalactolipids from the envelope membrane, changing the ratio of bilayer to nonbilayer forming membrane lipids. This SFR2-based mechanism compensates for changes in organelle volume and stabilizes membranes during freezing.

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Mitotic Recombination in Patients with Ichthyosis Causes Reversion of Dominant Mutations in KRT10.

Publication Date: 2010 Aug 26 PMID: 20798280
Authors: Choate, K. A. - Lu, Y. - Zhou, J. - Choi, M. - Elias, P. M. - Farhi, A. - Nelson-Williams, C. - Crumrine, D. - Williams, M. L. - Nopper, A. J. - Bree, A. - Milstone, L. M. - Lifton, R. P.
Journal: Science

Somatic loss of wild-type alleles can produce disease traits such as neoplasia. Conversely, somatic loss of disease-causing mutations can revert phenotypes; however, these events are infrequently observed. Here, we show that ichthyosis with confetti, a severe, sporadic skin disease in humans, is associated with thousands of revertant clones of normal skin that arise from loss of heterozygosity on chromosome 17q via mitotic recombination. This allowed us to map and identify disease-causing mutations in the gene ecoding keratin 10 (KRT10); all result in frameshifts into the same alternative reading frame, producing an arginine-rich C-terminal peptide that redirects keratin 10 from the cytokeratin filament network to the nucleolus. The high frequency of somatic reversion in ichthyosis with confetti suggests that revertant stem cell clones are under strong positive selection and/or that the rate of mitotic recombination is elevated in individuals with this disorder.

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Deep-Sea Oil Plume Enriches Indigenous Oil-Degrading Bacteria.

Publication Date: 2010 Aug 26 PMID: 20736401
Authors: Hazen, T. C. - Dubinsky, E. A. - Desantis, T. Z. - Andersen, G. L. - Piceno, Y. M. - Singh, N. - Jansson, J. K. - Probst, A. - Borglin, S. E. - Fortney, J. L. - Stringfellow, W. T. - Bill, M. - Conrad, M. S. - Tom, L. M. - Chavarria, K. L. - Alusi, T. R. - Lamendella, R. - Joyner, D. C. - Spier, C. - Baelum, J. - Auer, M. - Zemla, M. L. - Chakraborty, R. - Sonnenthal, E. L. - D'haeseleer, P. - Holman, H. Y. - Osman, S. - Lu, Z. - Van Nostrand, J. D. - Deng, Y. - Zhou, J. - Mason, O. U.
Journal: Science

The biological effects and expected fate of the vast amount of oil in the Gulf of Mexico from the Deepwater Horizon blowout are unknown due to the depth and magnitude of this event. Here, we report that the dispersed hydrocarbon plume stimulated deep-sea indigenous gamma-proteobacteria that are closely related to known petroleum-degraders. Hydrocarbon-degrading genes coincided with the concentration of various oil contaminants. Changes in hydrocarbon composition with distance from the source and incubation experiments with environmental isolates demonstrate faster-than-expected hydrocarbon biodegradation rates at 5 degrees C. Based on these results, the potential exists for intrinsic bioremediation of the oil plume in the deep-water column without substantial oxygen drawdown.

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Cell lineage reconstruction of early zebrafish embryos using label-free nonlinear microscopy.

Publication Date: 2010 Aug 20 PMID: 20724640
Authors: Olivier, N. - Luengo-Oroz, M. A. - Duloquin, L. - Faure, E. - Savy, T. - Veilleux, I. - Solinas, X. - Debarre, D. - Bourgine, P. - Santos, A. - Peyrieras, N. - Beaurepaire, E.
Journal: Science

Quantifying cell behaviors in animal early embryogenesis remains a challenging issue requiring in toto imaging and automated image analysis. We designed a framework for imaging and reconstructing unstained whole zebrafish embryos for their first 10 cell division cycles and report measurements along the cell lineage with micrometer spatial resolution and minute temporal accuracy. Point-scanning multiphoton excitation optimized to preferentially probe the innermost regions of the embryo provided intrinsic signals highlighting all mitotic spindles and cell boundaries. Automated image analysis revealed the phenomenology of cell proliferation. Blastomeres continuously drift out of synchrony. After the 32-cell stage, the cell cycle lengthens according to cell radial position, leading to apparent division waves. Progressive amplification of this process is the rule, contrasting with classical descriptions of abrupt changes in the system dynamics.

MeSH Categories: Animals, Blastula/cytology, Cell Cycle, *Cell Lineage, Embryo, Nonmammalian/*cytology, Image Processing, Computer-Assisted, Microscopy/*methods, Zebrafish/*embryology

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Females use multiple mating and genetically loaded sperm competition to target compatible genes.

Publication Date: 2010 Aug 20 PMID: 20724639
Authors: Pryke, S. R. - Rollins, L. A. - Griffith, S. C.
Journal: Science

Individuals in socially monogamous species may participate in copulations outside of the pair bond, resulting in extra-pair offspring. Although males benefit from such extra-pair behavior if they produce more offspring, the adaptive function of infidelity to females remains elusive. Here we show that female participation in extra-pair copulations, combined with a genetically loaded process of sperm competition, enables female finches to target genes that are optimally compatible with their own to ensure fertility and optimize offspring viability. Such female behavior, along with the postcopulatory processes demonstrated here, may provide an adaptive function of female infidelity in socially monogamous animals.

MeSH Categories: *Adaptation, Biological, Animals, Female, Fertilization/genetics, Finches/genetics/*physiology, Genes, Male, *Mating Preference, Animal, *Pair Bond, Selection, Genetic, Spermatozoa/*physiology

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mTOR-dependent synapse formation underlies the rapid antidepressant effects of NMDA antagonists.

Publication Date: 2010 Aug 20 PMID: 20724638
Authors: Li, N. - Lee, B. - Liu, R. J. - Banasr, M. - Dwyer, J. M. - Iwata, M. - Li, X. Y. - Aghajanian, G. - Duman, R. S.
Journal: Science

The rapid antidepressant response after ketamine administration in treatment-resistant depressed patients suggests a possible new approach for treating mood disorders compared to the weeks or months required for standard medications. However, the mechanisms underlying this action of ketamine [a glutamate N-methyl-D-aspartic acid (NMDA) receptor antagonist] have not been identified. We observed that ketamine rapidly activated the mammalian target of rapamycin (mTOR) pathway, leading to increased synaptic signaling proteins and increased number and function of new spine synapses in the prefrontal cortex of rats. Moreover, blockade of mTOR signaling completely blocked ketamine induction of synaptogenesis and behavioral responses in models of depression. Our results demonstrate that these effects of ketamine are opposite to the synaptic deficits that result from exposure to stress and could contribute to the fast antidepressant actions of ketamine.

MeSH Categories: Animals, Antidepressive Agents/pharmacokinetics/*pharmacology, Dendritic Spines/drug effects/metabolism, Depression/drug therapy/metabolism, Intracellular Signaling Peptides and Proteins/agonists, Ketamine/pharmacokinetics/*pharmacology, Male, Neurons/drug effects/metabolism, Neuropeptides/*biosynthesis/metabolism, Phenols/pharmacology, Piperidines/pharmacology, Protein Biosynthesis/drug effects, Protein-Serine-Threonine Kinases, Rats, Rats, Sprague-Dawley, Receptors, N-Methyl-D-Aspartate/*antagonists & inhibitors, Signal Transduction/drug effects, Sirolimus/pharmacology, Synapses/*drug effects/metabolism, Time Factors

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Linear arrays of nuclear envelope proteins harness retrograde actin flow for nuclear movement.

Publication Date: 2010 Aug 20 PMID: 20724637
Authors: Luxton, G. W. - Gomes, E. R. - Folker, E. S. - Vintinner, E. - Gundersen, G. G.
Journal: Science

Nuclei move to specific locations to polarize migrating and differentiating cells. Many nuclear movements are microtubule-dependent. However, nuclear movement to reorient the centrosome in migrating fibroblasts occurs through an unknown actin-dependent mechanism. We found that linear arrays of outer (nesprin2G) and inner (SUN2) nuclear membrane proteins assembled on and moved with retrogradely moving dorsal actin cables during nuclear movement in polarizing fibroblasts. Inhibition of nesprin2G, SUN2, or actin prevented nuclear movement and centrosome reorientation. The coupling of actin cables to the nuclear membrane for nuclear movement via specific membrane proteins indicates that, like plasma membrane integrins, nuclear membrane proteins assemble into actin-dependent arrays for force transduction.

MeSH Categories: Actins/*metabolism, Animals, Cell Movement/physiology, Cell Nucleus/*metabolism, Centrosome/physiology, Fibroblasts, Lysophospholipids/metabolism, Membrane Proteins/metabolism, Mice, Movement, NIH 3T3 Cells, Nerve Tissue Proteins/metabolism, Nuclear Envelope/*metabolism, Nuclear Proteins/*metabolism, Telomere-Binding Proteins/metabolism

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Conserved fungal LysM effector Ecp6 prevents chitin-triggered immunity in plants.

Publication Date: 2010 Aug 20 PMID: 20724636
Authors: de Jonge, R. - van Esse, H. P. - Kombrink, A. - Shinya, T. - Desaki, Y. - Bours, R. - van der Krol, S. - Shibuya, N. - Joosten, M. H. - Thomma, B. P.
Journal: Science

Multicellular organisms activate immunity upon recognition of pathogen-associated molecular patterns (PAMPs). Chitin is the major component of fungal cell walls, and chitin oligosaccharides act as PAMPs in plant and mammalian cells. Microbial pathogens deliver effector proteins to suppress PAMP-triggered host immunity and to establish infection. Here, we show that the LysM domain-containing effector protein Ecp6 of the fungal plant pathogen Cladosporium fulvum mediates virulence through perturbation of chitin-triggered host immunity. During infection, Ecp6 sequesters chitin oligosaccharides that are released from the cell walls of invading hyphae to prevent elicitation of host immunity. This may represent a common strategy of host immune suppression by fungal pathogens, because LysM effectors are widely conserved in the fungal kingdom.

MeSH Categories: Chitin/metabolism, Chitinase/metabolism, Cladosporium/immunology/*pathogenicity, Fungal Proteins/chemistry/immunology/*physiology, Lycopersicon esculentum/*immunology/microbiology, Plant Diseases/immunology/microbiology, Protein Binding, Protein Structure, Tertiary, Trichoderma/physiology

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Chloroplasts divide by contraction of a bundle of nanofilaments consisting of polyglucan.

Publication Date: 2010 Aug 20 PMID: 20724635
Authors: Yoshida, Y. - Kuroiwa, H. - Misumi, O. - Yoshida, M. - Ohnuma, M. - Fujiwara, T. - Yagisawa, F. - Hirooka, S. - Imoto, Y. - Matsushita, K. - Kawano, S. - Kuroiwa, T.
Journal: Science

In chloroplast division, the plastid-dividing (PD) ring is a main structure of the PD machinery and is a universal structure in the plant kingdom. However, the components and formation of the PD ring have been enigmatic. By proteomic analysis of PD machineries isolated from Cyanidioschyzon merolae, we identified the glycosyltransferase protein plastid-dividing ring 1 (PDR1), which constructs the PD ring and is widely conserved from red alga to land plants. Electron microscopy showed that the PDR1 protein forms a ring with carbohydrates at the chloroplast-division site. Fluorometric saccharide ingredient analysis of purified PD ring filaments showed that only glucose was included, and down-regulation of PDR1 impaired chloroplast division. Thus, the chloroplasts are divided by the PD ring, which is a bundle of PDR1-mediated polyglucan filaments.

MeSH Categories: Algae, Red/genetics/*physiology/ultrastructure, Algal Proteins/genetics/isolation & purification/*physiology, Chloroplasts/chemistry/*physiology/ultrastructure, Cytoskeleton/chemistry/*physiology, Down-Regulation, Glucans/isolation & purification/*physiology, Glycosyltransferases/genetics/isolation & purification/*physiology, Protein Binding, Proteomics, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

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Loss of DNA replication control is a potent inducer of gene amplification.

Publication Date: 2010 Aug 20 PMID: 20724634
Authors: Green, B. M. - Finn, K. J. - Li, J. J.
Journal: Science

Eukaryotic cells use numerous mechanisms to ensure that no segment of their DNA is inappropriately re-replicated, but the importance of this stringent control on genome stability has not been tested. Here we show that re-replication in Saccharomyces cerevisiae can strongly induce the initial step of gene amplification, increasing gene copy number from one to two or more. The resulting amplicons consist of large internal chromosomal segments that are bounded by Ty repetitive elements and are intrachromosomally arrayed at their endogenous locus in direct head-to-tail orientation. These re-replication-induced gene amplifications are mediated by nonallelic homologous recombination between the repetitive elements. We suggest that re-replication may be a contributor to gene copy number changes, which are important in fields such as cancer biology, evolution, and human genetics.

MeSH Categories: Cell Cycle, *DNA Replication, DNA, Fungal/biosynthesis, *Gene Amplification, Gene Dosage, Recombination, Genetic, Saccharomyces cerevisiae/genetics

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Drought-induced reduction in global terrestrial net primary production from 2000 through 2009.

Publication Date: 2010 Aug 20 PMID: 20724633
Authors: Zhao, M. - Running, S. W.
Journal: Science

Terrestrial net primary production (NPP) quantifies the amount of atmospheric carbon fixed by plants and accumulated as biomass. Previous studies have shown that climate constraints were relaxing with increasing temperature and solar radiation, allowing an upward trend in NPP from 1982 through 1999. The past decade (2000 to 2009) has been the warmest since instrumental measurements began, which could imply continued increases in NPP; however, our estimates suggest a reduction in the global NPP of 0.55 petagrams of carbon. Large-scale droughts have reduced regional NPP, and a drying trend in the Southern Hemisphere has decreased NPP in that area, counteracting the increased NPP over the Northern Hemisphere. A continued decline in NPP would not only weaken the terrestrial carbon sink, but it would also intensify future competition between food demand and proposed biofuel production.

MeSH Categories: *Atmosphere, Biomass, Carbon/*metabolism, *Droughts, Ecosystem, Plants/*metabolism

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Evidence of recent thrust faulting on the Moon revealed by the Lunar Reconnaissance Orbiter Camera.

Publication Date: 2010 Aug 20 PMID: 20724632
Authors: Watters, T. R. - Robinson, M. S. - Beyer, R. A. - Banks, M. E. - Bell, J. F. 3rd - Pritchard, M. E. - Hiesinger, H. - van der Bogert, C. H. - Thomas, P. C. - Turtle, E. P. - Williams, N. R.
Journal: Science

Lunar Reconnaissance Orbiter Camera images reveal previously undetected lobate thrust-fault scarps and associated meter-scale secondary tectonic landforms that include narrow extensional troughs or graben, splay faults, and multiple low-relief terraces. Lobate scarps are among the youngest landforms on the Moon, based on their generally crisp appearance, lack of superposed large-diameter impact craters, and the existence of crosscut small-diameter impact craters. Identification of previously known scarps was limited to high-resolution Apollo Panoramic Camera images confined to the equatorial zone. Fourteen lobate scarps were identified, seven of which are at latitudes greater than +/-60 degrees, indicating that the thrust faults are globally distributed. This detection, coupled with the very young apparent age of the faults, suggests global late-stage contraction of the Moon.

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Ceria maintains smaller metal catalyst particles by strong metal-support bonding.

Publication Date: 2010 Aug 20 PMID: 20724631
Authors: Farmer, J. A. - Campbell, C. T.
Journal: Science

The energies of silver (Ag) atoms in Ag nanoparticles supported on different cerium and magnesium oxide surfaces, determined from previous calorimetric measurements of metal adsorption energies, were analyzed with respect to particle size. Their stability was found to increase with particle size below 5000 atoms per particle. Silver nanoparticles of any given size below 1000 atoms had much higher stability (30 to 70 kilojoules per mole of silver atoms) on reduced CeO2(111) than on MgO(100). This effect is the result of the very large adhesion energy (approximately 2.3 joules per square meter) of Ag nanoparticles to reduced CeO2(111), which we found to be a result of strong bonding to both defects and CeO2(111) terraces, apparently localized by lattice strain. These results explain the unusual sinter resistance of late transition metal catalysts when supported on ceria.

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Unidirectional emission of a quantum dot coupled to a nanoantenna.

Publication Date: 2010 Aug 20 PMID: 20724630
Authors: Curto, A. G. - Volpe, G. - Taminiau, T. H. - Kreuzer, M. P. - Quidant, R. - van Hulst, N. F.
Journal: Science

Nanoscale quantum emitters are key elements in quantum optics and sensing. However, efficient optical excitation and detection of such emitters involves large solid angles because their interaction with freely propagating light is omnidirectional. Here, we present unidirectional emission of a single emitter by coupling to a nanofabricated Yagi-Uda antenna. A quantum dot is placed in the near field of the antenna so that it drives the resonant feed element of the antenna. The resulting quantum-dot luminescence is strongly polarized and highly directed into a narrow forward angular cone. The directionality of the quantum dot can be controlled by tuning the antenna dimensions. Our results show the potential of optical antennas to communicate energy to, from, and between nano-emitters.

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Dual jets from binary black holes.

Publication Date: 2010 Aug 20 PMID: 20724629
Authors: Palenzuela, C. - Lehner, L. - Liebling, S. L.
Journal: Science

The coalescence of supermassive black holes--a natural outcome when galaxies merge--should produce gravitational waves and would likely be associated with energetic electromagnetic events. We have studied the coalescence of such binary black holes within an external magnetic field produced by the expected circumbinary disk surrounding them. Solving the Einstein equations to describe black holes interacting with surrounding plasma, we present numerical evidence for possible jets driven by these systems. Extending the process described by Blandford and Znajek for a single, spinning black hole, the picture that emerges suggests that the electromagnetic field extracts energy from the orbiting black holes, which ultimately merge and settle into the standard Blandford-Znajek scenario. Emissions along these jets could potentially be observable at large distances.

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Cosmological constraints from strong gravitational lensing in clusters of galaxies.

Publication Date: 2010 Aug 20 PMID: 20724628
Authors: Jullo, E. - Natarajan, P. - Kneib, J. P. - D'Aloisio, A. - Limousin, M. - Richard, J. - Schimd, C.
Journal: Science

Current efforts in observational cosmology are focused on characterizing the mass-energy content of the universe. We present results from a geometric test based on strong lensing in galaxy clusters. Based on Hubble Space Telescope images and extensive ground-based spectroscopic follow-up of the massive galaxy cluster Abell 1689, we used a parametric model to simultaneously constrain the cluster mass distribution and dark energy equation of state. Combining our cosmological constraints with those from x-ray clusters and the Wilkinson Microwave Anisotropy Probe 5-year data gives Omega(m) = 0.25 +/- 0.05 and w(x) = -0.97 +/- 0.07, which are consistent with results from other methods. Inclusion of our method with all other available techniques brings down the current 2sigma contours on the dark energy equation-of-state parameter w(x) by approximately 30%.

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Immunology. Double TIP-ping.

Publication Date: 2010 Aug 20 PMID: 20724627
Authors: Singh, H. - Demarco, I. A.
Journal: Science

MeSH Categories: Acetylation, Animals, Antibody Specificity/*genetics, B-Lymphocytes/*immunology, Carrier Proteins/genetics/*physiology, Cells, Cultured, Chromatin/metabolism, Cytidine Deaminase/*metabolism, DNA, DNA Breaks, Double-Stranded, DNA Modification Methylases/metabolism, Histone-Lysine N-Methyltransferase/genetics, Histones/metabolism, Immunoglobulin Class Switching/genetics/*physiology, Immunoglobulin Switch Region, Lymphocyte Activation, Methylation, Mice, Mice, Knockout, Nuclear Proteins/genetics/*physiology, Promoter Regions, Genetic, Recombination, Genetic, Transcriptional Activation

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Neuroscience. A glutamate pathway to faster-acting antidepressants?

Publication Date: 2010 Aug 20 PMID: 20724626
Authors: Cryan, J. F. - O'Leary, O. F.
Journal: Science

MeSH Categories: Animals, Antidepressive Agents/*pharmacokinetics, Drug Synergism, Excitatory Amino Acid Antagonists/*pharmacology/therapeutic use, Humans, Intracellular Signaling Peptides and Proteins/antagonists &, inhibitors/metabolism, Ketamine/*pharmacology/therapeutic use, Protein-Serine-Threonine Kinases/antagonists & inhibitors/metabolism, Rats, Sirolimus/pharmacology, Synaptic Transmission/drug effects

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Genetics. Replication error amplified.

Publication Date: 2010 Aug 20 PMID: 20724625
Authors: Kaochar, S. - Paek, A. L. - Weinert, T.
Journal: Science

MeSH Categories: Cyclin-Dependent Kinases/metabolism, *DNA Replication, DNA, Fungal, DNA, Neoplasm, *Gene Amplification, Humans, Neoplasms/genetics, Replication Origin, Saccharomycetales

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Physics. Directing light emission from quantum dots.

Publication Date: 2010 Aug 20 PMID: 20724624
Authors: Giessen, H. - Lippitz, M.
Journal: Science

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Cell biology. Nuclei get TAN lines.

Publication Date: 2010 Aug 20 PMID: 20724623
Authors: Starr, D. A.
Journal: Science

MeSH Categories: Actins/*physiology, Animals, Cell Movement, Cell Nucleus/*physiology, Cytoskeleton/physiology, Fibroblasts, Movement

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Astronomy. A tale of two jets.

Publication Date: 2010 Aug 20 PMID: 20724622
Authors: Yunes, N.
Journal: Science

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Science education. Partnerships for STEM education.

Publication Date: 2010 Aug 20 PMID: 20724621
Authors: Foster, K. M. - Bergin, K. B. - McKenna, A. F. - Millard, D. L. - Perez, L. C. - Prival, J. T. - Rainey, D. Y. - Sevian, H. M. - VanderPutten, E. A. - Hamos, J. E.
Journal: Science

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Comment on "The silicate-mediated formose reaction: bottom-up synthesis of sugar silicates".

Publication Date: 2010 Aug 20 PMID: 20724620
Authors: Kim, H. J. - Benner, S. A.
Journal: Science

Lambert et al. (Reports, 19 February 2010, p. 984) reported that silicate ions catalyze the formation and stabilization of four- and six-carbon sugars from simple sugars, suggesting a possible prebiotic pathway for the synthesis of biologically important sugars. Here, we show that silicate has minimal impact in these respects, especially when compared to borate minerals.

MeSH Categories: Acetaldehyde/analogs & derivatives/chemistry, Arabinose/*chemical synthesis/chemistry, Borates/chemistry, Carbohydrates/*chemical synthesis/chemistry, Chemical Processes, Glyceraldehyde/chemistry, Hydrogen-Ion Concentration, Mass Spectrometry, Ribose/chemistry, Silicates/*chemistry, Spectrometry, Mass, Electrospray Ionization, Temperature

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Putting census data to work.

Publication Date: 2010 Aug 20 PMID: 20724619
Authors: Brewer, T. D.
Journal: Science

MeSH Categories: *Censuses, China, Data Collection, Demography, Humans, *Sociology

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Life in science. Up a creek in Indonesia.

Publication Date: 2010 Aug 20 PMID: 20724618
Authors: Beehler, B. M.
Journal: Science

MeSH Categories: Animals, *Animals, Wild, *Biodiversity, Indonesia, Wit and Humor as Topic

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Local programs take a bite out of malaria.

Publication Date: 2010 Aug 20 PMID: 20724617
Authors: Shiff, C. J. - Thuma, P.
Journal: Science

MeSH Categories: Communicable Disease Control/organization & administration/standards, *Delivery of Health Care/organization & administration/standards, Humans, Malaria/*prevention & control, Zambia, Zimbabwe

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National indicators show biodiversity progress.

Publication Date: 2010 Aug 20 PMID: 20724616
Authors: Xu, H. - Ding, H. - Wu, J.
Journal: Science

MeSH Categories: *Biodiversity, China, *Conservation of Natural Resources, Environmental Pollution/prevention & control, Trees

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Plant science. Pavlovsk's hopes hang on a tweet.

Publication Date: 2010 Aug 20 PMID: 20724614
Authors: Parfitt, T.
Journal: Science

MeSH Categories: *Biological Specimen Banks, *Crops, Agricultural/genetics, Databases, Genetic, *Fruit/genetics, *Genes, Plant, *Plants/genetics, Russia, Seeds, Software

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Free journals grow amid ongoing debate.

Publication Date: 2010 Aug 20 PMID: 20724613
Authors: Kaiser, J.
Journal: Science

MeSH Categories: *Access to Information, Bibliometrics, Libraries, Digital, Peer Review, Research, *Periodicals as Topic/economics/trends, *Publishing/economics/standards, United States

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Astronomy. U.S. astronomers unveil stripped-down 'short list'.

Publication Date: 2010 Aug 20 PMID: 20724612
Authors: Bhattacharjee, Y.
Journal: Science

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U.S. science budget. Senator builds his legacy with University of Alabama earmarks.

Publication Date: 2010 Aug 20 PMID: 20724611
Authors: Mervis, J.
Journal: Science

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Molecular genetics. One-two punch elevates rats to the knockout ranks.

Publication Date: 2010 Aug 20 PMID: 20724610
Authors: Normile, D.
Journal: Science

MeSH Categories: Animals, Cell Culture Techniques, Culture Media, DNA Transposable Elements, Deoxyribonucleases/metabolism, Embryonic Stem Cells/cytology/physiology, *Gene Knockout Techniques, Mice, Mice, Knockout, Rats/*genetics, Recombination, Genetic, Zinc Fingers

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Cognition research. Investigation leaves field in the dark about a colleague's work.

Publication Date: 2010 Aug 20 PMID: 20724607
Authors: Miller, G.
Journal: Science

MeSH Categories: Animals, Biomedical Research/*standards, *Cognition, History, 21st Century, Massachusetts, Primates/*psychology, *Retraction of Publication as Topic, Scientific Misconduct, Universities

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Gulf oil spill. After outcry, oil data inches into the open.

Publication Date: 2010 Aug 20 PMID: 20724606
Authors: Schenkman, L.
Journal: Science

MeSH Categories: *Accidents, Atlantic Ocean, *Consultants, Contracts, *Environment, Information Dissemination, *Petroleum, *Publishing, United States, United States Government Agencies

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Gulf oil spill. The case of the missing $470 million in BP's promised research fund.

Publication Date: 2010 Aug 20 PMID: 20724605
Authors: Schenkman, L.
Journal: Science

MeSH Categories: *Accidents, Animals, Anthozoa, Atlantic Ocean, Birds, *Environment, Fishes, Industry/economics, *Petroleum, Research/economics/organization & administration, *Research Support as Topic

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Nurturing young scientists.

Publication Date: 2010 Aug 20 PMID: 20724604
Authors: Gentile, J. - Boehlert, S.
Journal: Science

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A Vibrio Effector Protein is an Inositol Phosphatase and Disrupts Host Cell Membrane Integrity.

Publication Date: 2010 Aug 19 PMID: 20724587
Authors: Broberg, C. A. - Zhang, L. - Gonzalez, H. - Laskowski-Arce, M. A. - Orth, K.
Journal: Science

The marine bacterium Vibrio parahaemolyticus causes gastroenteritis in humans and encodes the type III effector protein VPA0450, which contributes to host cell death caused by autophagy, cell rounding, and cell lysis. We found that VPA0450 is an inositol polyphosphate 5-phosphatase that hydrolyzed the D5 phosphate from the plasma membrane phospholipid PtdIns(4,5)P(2). VPA0450 disrupted cytoskeletal binding sites on the inner surface of membranes of human cells and caused plasma membrane blebbing, which compromised membrane integrity and probably contributed to cell death by facilitating lysis. Thus, bacterial pathogens can disrupt adaptor protein binding sites required for proper membrane and cytoskeleton dynamics by altering the homeostasis of membrane-bound inositol signaling molecules.

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Plastic Accumulation in the North Atlantic Subtropical Gyre.

Publication Date: 2010 Aug 19 PMID: 20724586
Authors: Law, K. L. - Moret-Ferguson, S. - Maximenko, N. A. - Proskurowski, G. - Peacock, E. E. - Hafner, J. - Reddy, C. M.
Journal: Science

Plastic marine pollution is a significant environmental concern, yet a quantitative description of the scope of this problem in the open ocean is lacking. Here, we present a time series of plastic content at the surface of the western North Atlantic Ocean and Caribbean Sea from 1986 to 2008. More than 60% of 6136 surface plankton net tows collected buoyant plastic pieces typically millimeters in size. The highest concentration of plastic debris was observed in subtropical latitudes and associated with the observed large-scale convergence in surface currents predicted by Ekman dynamics. Despite a rapid increase in plastic production and disposal during this time period, no trend in plastic concentration was observed in the region of highest accumulation.

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A Red-Shifted Chlorophyll.

Publication Date: 2010 Aug 19 PMID: 20724585
Authors: Chen, M. - Schliep, M. - Willows, R. D. - Cai, Z. L. - Neilan, B. A. - Scheer, H.
Journal: Science

Chlorophylls are essential for light-harvesting and energy transduction in photosynthesis. Four chemically distinct varieties have been known for the past 60 years. Here, we report isolation of a fifth, which we designate chlorophyll f. Its in vitro absorption (706 nm) and fluorescence (722 nm) maxima are red-shifted compared to all other chlorophylls from oxygenic phototrophs. Based on the optical, mass, and nuclear magnetic resonance spectra, we propose that chlorophyll f is [2-formyl]-chlorophyll a (C(55)H(70)O(6)N(4)Mg). This finding suggests that oxygenic photosynthesis can be extended further into the infrared region and may open associated bioenergy applications.

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Tracking Hydrocarbon Plume Transport and Biodegradation at Deepwater Horizon.

Publication Date: 2010 Aug 19 PMID: 20724584
Authors: Camilli, R. - Reddy, C. M. - Yoerger, D. R. - Van Mooy, B. A. - Jakuba, M. V. - Kinsey, J. C. - McIntyre, C. P. - Sylva, S. P. - Maloney, J. V.
Journal: Science

The Deepwater Horizon blowout is the largest offshore oil spill in history. We present results from a subsurface hydrocarbon survey using an autonomous underwater vehicle and a ship-cabled sampler. Our findings indicate the presence of a continuous plume over 35 km in length, at approximately 1100 m depth that persisted for months without substantial biodegradation. Samples collected from within the plume reveal monoaromatic petroleum hydrocarbon concentrations in excess of 50 microg L(-1). These data indicate that monoaromatic input to this plume was at least 5500 kg day(-1), which is more than double the total source rate of all natural seeps of the monoaromatic petroleum hydrocarbons in the northern Gulf of Mexico. Dissolved oxygen concentrations suggest that microbial respiration rates within the plume were not appreciably more than 1 microM O(2) day(-1).

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A Unifying Genetic Model for Facioscapulohumeral Muscular Dystrophy.

Publication Date: 2010 Aug 19 PMID: 20724583
Authors: Lemmers, R. J. - van der Vliet, P. J. - Klooster, R. - Sacconi, S. - Camano, P. - Dauwerse, J. G. - Snider, L. - Straasheijm, K. R. - Jan van Ommen, G. - Padberg, G. W. - Miller, D. G. - Tapscott, S. J. - Tawil, R. - Frants, R. R. - van der Maarel, S. M.
Journal: Science

Facioscapulohumeral muscular dystrophy (FSHD) is a common form of muscular dystrophy in adults that is foremost characterized by progressive wasting of muscles in the upper body. FSHD is associated with contraction of D4Z4 macrosatellite repeats on chromosome 4q35, but this contraction is pathogenic only in certain "permissive" chromosomal backgrounds. Here, we show that FSHD patients carry specific single nucleotide polymorphisms (SNPs) in the chromosomal region distal to the last D4Z4 repeat. This FSHD-predisposing configuration creates a canonical polyadenylation signal for transcripts derived from DUX4, a double homeobox gene of unknown function that straddles the last repeat unit and the adjacent sequence. Transfection studies revealed that DUX4 transcripts are efficiently polyadenylated and are more stable when expressed from permissive chromosomes. These findings suggest that FSHD arises through a toxic gain of function attributable to the stabilized distal DUX4 transcript.

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Stability of ecological communities and the architecture of mutualistic and trophic networks.

Publication Date: 2010 Aug 13 PMID: 20705861
Authors: Thebault, E. - Fontaine, C.
Journal: Science

Research on the relationship between the architecture of ecological networks and community stability has mainly focused on one type of interaction at a time, making difficult any comparison between different network types. We used a theoretical approach to show that the network architecture favoring stability fundamentally differs between trophic and mutualistic networks. A highly connected and nested architecture promotes community stability in mutualistic networks, whereas the stability of trophic networks is enhanced in compartmented and weakly connected architectures. These theoretical predictions are supported by a meta-analysis on the architecture of a large series of real pollination (mutualistic) and herbivory (trophic) networks. We conclude that strong variations in the stability of architectural patterns constrain ecological networks toward different architectures, depending on the type of interaction.

MeSH Categories: Algorithms, Animals, *Ecosystem, Food Chain, Insects/*physiology, *Models, Biological, *Plant Physiological Phenomena, *Pollination, Population Dynamics, *Symbiosis

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Activation of beta-catenin in dendritic cells regulates immunity versus tolerance in the intestine.

Publication Date: 2010 Aug 13 PMID: 20705860
Authors: Manicassamy, S. - Reizis, B. - Ravindran, R. - Nakaya, H. - Salazar-Gonzalez, R. M. - Wang, Y. C. - Pulendran, B.
Journal: Science

Dendritic cells (DCs) play a vital role in initiating robust immunity against pathogens as well as maintaining immunological tolerance to self antigens. However, the intracellular signaling networks that program DCs to become tolerogenic remain unknown. We report here that the Wnt-beta-catenin signaling in intestinal dendritic cells regulates the balance between inflammatory versus regulatory responses in the gut. beta-catenin in intestinal dendritic cells was required for the expression of anti-inflammatory mediators such as retinoic acid-metabolizing enzymes, interleukin-10, and transforming growth factor-beta, and the stimulation of regulatory T cell induction while suppressing inflammatory effector T cells. Furthermore, ablation of beta-catenin expression in DCs enhanced inflammatory responses and disease in a mouse model of inflammatory bowel disease. Thus, beta-catenin signaling programs DCs to a tolerogenic state, limiting the inflammatory response.

MeSH Categories: Animals, Cytokines/metabolism, Dendritic Cells/*immunology/metabolism, Gene Expression Profiling, *Inflammation, Inflammatory Bowel Diseases/*immunology, Intestinal Mucosa/cytology/*immunology/metabolism, Macrophages/immunology/metabolism, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Oligonucleotide Array Sequence Analysis, *Self Tolerance, Signal Transduction, T-Lymphocytes, Helper-Inducer/cytology/*immunology, T-Lymphocytes, Regulatory/*immunology, Tretinoin/metabolism, Wnt Proteins/metabolism, beta Catenin/*metabolism

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An allosteric self-splicing ribozyme triggered by a bacterial second messenger.

Publication Date: 2010 Aug 13 PMID: 20705859
Authors: Lee, E. R. - Baker, J. L. - Weinberg, Z. - Sudarsan, N. - Breaker, R. R.
Journal: Science

Group I self-splicing ribozymes commonly function as components of selfish mobile genetic elements. We identified an allosteric group I ribozyme, wherein self-splicing is regulated by a distinct riboswitch class that senses the bacterial second messenger c-di-GMP. The tandem RNA sensory system resides in the 5' untranslated region of the messenger RNA for a putative virulence gene in the pathogenic bacterium Clostridium difficile. c-di-GMP binding by the riboswitch induces folding changes at atypical splice site junctions to modulate alternative RNA processing. Our findings indicate that some self-splicing ribozymes are not selfish elements but are harnessed by cells as metabolite sensors and genetic regulators.

MeSH Categories: 5' Untranslated Regions, Aptamers, Nucleotide/chemistry, Base Pairing, Base Sequence, Clostridium difficile/*genetics/metabolism/pathogenicity, Codon, Initiator, Cyclic GMP/*analogs & derivatives/metabolism, Exons, Genes, Bacterial, Guanosine Triphosphate/metabolism, Molecular Sequence Data, Nucleic Acid Conformation, *RNA Splicing, RNA, Bacterial/chemistry/*genetics/metabolism, RNA, Catalytic/chemistry/genetics/*metabolism, RNA, Messenger/chemistry/genetics/metabolism, *Regulatory Sequences, Ribonucleic Acid, *Second Messenger Systems

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Three-dimensional, flexible nanoscale field-effect transistors as localized bioprobes.

Publication Date: 2010 Aug 13 PMID: 20705858
Authors: Tian, B. - Cohen-Karni, T. - Qing, Q. - Duan, X. - Xie, P. - Lieber, C. M.
Journal: Science

Nanoelectronic devices offer substantial potential for interrogating biological systems, although nearly all work has focused on planar device designs. We have overcome this limitation through synthetic integration of a nanoscale field-effect transistor (nanoFET) device at the tip of an acute-angle kinked silicon nanowire, where nanoscale connections are made by the arms of the kinked nanostructure, and remote multilayer interconnects allow three-dimensional (3D) probe presentation. The acute-angle probe geometry was designed and synthesized by controlling cis versus trans crystal conformations between adjacent kinks, and the nanoFET was localized through modulation doping. 3D nanoFET probes exhibited conductance and sensitivity in aqueous solution, independent of large mechanical deflections, and demonstrated high pH sensitivity. Additionally, 3D nanoprobes modified with phospholipid bilayers can enter single cells to allow robust recording of intracellular potentials.

MeSH Categories: Animals, *Biosensing Techniques/instrumentation/methods, Cell Line, Cells, Cultured, Chick Embryo, Electric Conductivity, Electrophysiological Phenomena, Equipment Design, Hydrogen-Ion Concentration, Lipid Bilayers, Membrane Potentials, Mice, Microfluidics, Myocytes, Cardiac/*physiology, *Nanowires, Sensitivity and Specificity, Sodium Chloride, *Transistors, Electronic

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Small-scale mantle convection produces stratigraphic sequences in sedimentary basins.

Publication Date: 2010 Aug 13 PMID: 20705857
Authors: Petersen, K. D. - Nielsen, S. B. - Clausen, O. R. - Stephenson, R. - Gerya, T.
Journal: Science

Cyclic sedimentary deposits link stratigraphic sequences that are now geographically distant but were once part of the same depositional environment. Some of these sequences occur at periods of 2 to 20 million years, and eustatic sea-level variations or regional tectonic events are likely causes of their formation. Using numerical modeling, we demonstrate that small-scale mantle convection can also cause the development of stratigraphic sequences through recurrent local and regional vertical surface movements. Small-scale convection-driven stratigraphic sequences occur at periods of 2 to 20 million years and correlate only at distances up to a few hundred kilometers. These results suggest that previous sequence stratigraphic analyses may contain erroneous conclusions regarding eustatic sea-level variations.

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In-plane resistivity anisotropy in an underdoped iron arsenide superconductor.

Publication Date: 2010 Aug 13 PMID: 20705856
Authors: Chu, J. H. - Analytis, J. G. - De Greve, K. - McMahon, P. L. - Islam, Z. - Yamamoto, Y. - Fisher, I. R.
Journal: Science

High-temperature superconductivity often emerges in the proximity of a symmetry-breaking ground state. For superconducting iron arsenides, in addition to the antiferromagnetic ground state, a small structural distortion breaks the crystal's C(4 )rotational symmetry in the underdoped part of the phase diagram. We reveal that the representative iron arsenide Ba(Fe(1)(-x)Co(x))(2)As(2) develops a large electronic anisotropy at this transition via measurements of the in-plane resistivity of detwinned single crystals, with the resistivity along the shorter b axis rho(b) being greater than rho(a). The anisotropy reaches a maximum value of ~2 for compositions in the neighborhood of the beginning of the superconducting dome. For temperatures well above the structural transition, uniaxial stress induces a resistivity anisotropy, indicating a substantial nematic susceptibility.

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Gamma-ray emission concurrent with the nova in the symbiotic binary V407 Cygni.

Publication Date: 2010 Aug 13 PMID: 20705855
Authors: Abdo, A. A. - Ackermann, M. - Ajello, M. - Atwood, W. B. - Baldini, L. - Ballet, J. - Barbiellini, G. - Bastieri, D. - Bechtol, K. - Bellazzini, R. - Berenji, B. - Blandford, R. D. - Bloom, E. D. - Bonamente, E. - Borgland, A. W. - Bouvier, A. - Brandt, T. J. - Bregeon, J. - Brez, A. - Brigida, M. - Bruel, P. - Buehler, R. - Burnett, T. H. - Buson, S. - Caliandro, G. A. - Cameron, R. A. - Caraveo, P. A. - Carrigan, S. - Casandjian, J. M. - Cecchi, C. - Celik, O. - Charles, E. - Chaty, S. - Chekhtman, A. - Cheung, C. C. - Chiang, J. - Ciprini, S. - Claus, R. - Cohen-Tanugi, J. - Conrad, J. - Corbel, S. - Corbet, R. - DeCesar, M. E. - den Hartog, P. R. - Dermer, C. D. - de Palma, F. - Digel, S. W. - Donato, D. - do Couto e Silva, E. - Drell, P. S. - Dubois, R. - Dubus, G. - Dumora, D. - Favuzzi, C. - Fegan, S. J. - Ferrara, E. C. - Fortin, P. - Frailis, M. - Fuhrmann, L. - Fukazawa, Y. - Funk, S. - Fusco, P. - Gargano, F. - Gasparrini, D. - Gehrels, N. - Germani, S. - Giglietto, N. - Giordano, F. - Giroletti, M. - Glanzman, T. - Godfrey, G. - Grenier, I. A. - Grondin, M. H. - Grove, J. E. - Guiriec, S. - Hadasch, D. - Harding, A. K. - Hayashida, M. - Hays, E. - Healey, S. E. - Hill, A. B. - Horan, D. - Hughes, R. E. - Itoh, R. - Jean, P. - Johannesson, G. - Johnson, A. S. - Johnson, R. P. - Johnson, T. J. - Johnson, W. N. - Kamae, T. - Katagiri, H. - Kataoka, J. - Kerr, M. - Knodlseder, J. - Koerding, E. - Kuss, M. - Lande, J. - Latronico, L. - Lee, S. H. - Lemoine-Goumard, M. - Garde, M. L. - Longo, F. - Loparco, F. - Lott, B. - Lovellette, M. N. - Lubrano, P. - Makeev, A. - Mazziotta, M. N. - McConville, W. - McEnery, J. E. - Mehault, J. - Michelson, P. F. - Mizuno, T. - Moiseev, A. A. - Monte, C. - Monzani, M. E. - Morselli, A. - Moskalenko, I. V. - Murgia, S. - Nakamori, T. - Naumann-Godo, M. - Nestoras, I. - Nolan, P. L. - Norris, J. P. - Nuss, E. - Ohno, M. - Ohsugi, T. - Okumura, A. - Omodei, N. - Orlando, E. - Ormes, J. F. - Ozaki, M. - Paneque, D. - Panetta, J. H. - Parent, D. - Pelassa, V. - Pepe, M. - Pesce-Rollins, M. - Piron, F. - Porter, T. A. - Raino, S. - Rando, R. - Ray, P. S. - Razzano, M. - Razzaque, S. - Rea, N. - Reimer, A. - Reimer, O. - Reposeur, T. - Ripken, J. - Ritz, S. - Romani, R. W. - Roth, M. - Sadrozinski, H. F. - Sander, A. - Parkinson, P. M. - Scargle, J. D. - Schinzel, F. K. - Sgro, C. - Shaw, M. S. - Siskind, E. J. - Smith, D. A. - Smith, P. D. - Sokolovsky, K. V. - Spandre, G. - Spinelli, P. - Stawarz, L. - Strickman, M. S. - Suson, D. J. - Takahashi, H. - Takahashi, T. - Tanaka, T. - Tanaka, Y. - Thayer, J. B. - Thayer, J. G. - Thompson, D. J. - Tibaldo, L. - Torres, D. F. - Tosti, G. - Tramacere, A. - Uchiyama, Y. - Usher, T. L. - Vandenbroucke, J. - Vasileiou, V. - Vilchez, N. - Vitale, V. - Waite, A. P. - Wallace, E. - Wang, P. - Winer, B. L. - Wolff, M. T. - Wood, K. S. - Yang, Z. - Ylinen, T. - Ziegler, M. - Maehara, H. - Nishiyama, K. - Kabashima, F. - Bach, U. - Bower, G. C. - Falcone, A. - Forster, J. R. - Henden, A. - Kawabata, K. S. - Koubsky, P. - Mukai, K. - Nelson, T. - Oates, S. R. - Sakimoto, K. - Sasada, M. - Shenavrin, V. I. - Shore, S. N. - Skinner, G. K. - Sokoloski, J. - Stroh, M. - Tatarnikov, A. M. - Uemura, M. - Wahlgren, G. M. - Yamanaka, M.
Journal: Science

Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable gamma-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce pi(0) decay gamma-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.

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Generating the option of a two-stage nuclear renaissance.

Publication Date: 2010 Aug 13 PMID: 20705854
Authors: Grimes, R. W. - Nuttall, W. J.
Journal: Science

Concerns about climate change, security of supply, and depleting fossil fuel reserves have spurred a revival of interest in nuclear power generation in Europe and North America, while other regions continue or initiate an expansion. We suggest that the first stage of this process will include replacing or extending the life of existing nuclear power plants, with continued incremental improvements in efficiency and reliability. After 2030, a large-scale second period of construction would allow nuclear energy to contribute substantially to the decarbonization of electricity generation. For nuclear energy to be sustainable, new large-scale fuel cycles will be required that may include fuel reprocessing. Here, we explore the opportunities and constraints in both time periods and suggests ways in which measures taken today might, at modest cost, provide more options in the decades to come. Careful long-term planning, along with parallel efforts aimed at containing waste products and avoiding diversion of material into weapons production, can ensure that nuclear power generation remains a carbon-neutral option.

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An outlook on microalgal biofuels.

Publication Date: 2010 Aug 13 PMID: 20705853
Authors: Wijffels, R. H. - Barbosa, M. J.
Journal: Science

Microalgae are considered one of the most promising feedstocks for biofuels. The productivity of these photosynthetic microorganisms in converting carbon dioxide into carbon-rich lipids, only a step or two away from biodiesel, greatly exceeds that of agricultural oleaginous crops, without competing for arable land. Worldwide, research and demonstration programs are being carried out to develop the technology needed to expand algal lipid production from a craft to a major industrial process. Although microalgae are not yet produced at large scale for bulk applications, recent advances-particularly in the methods of systems biology, genetic engineering, and biorefining-present opportunities to develop this process in a sustainable and economical way within the next 10 to 15 years.

MeSH Categories: *Algae/genetics/growth & development/metabolism, *Biofuels/economics, Biomass, Bioreactors, Biotechnology/methods, Carbon Dioxide/metabolism, Genetic Engineering, Lipid Metabolism, *Lipids, Sunlight, Technology, Water

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Challenges in scaling up biofuels infrastructure.

Publication Date: 2010 Aug 13 PMID: 20705852
Authors: Richard, T. L.
Journal: Science

Rapid growth in demand for lignocellulosic bioenergy will require major changes in supply chain infrastructure. Even with densification and preprocessing, transport volumes by mid-century are likely to exceed the combined capacity of current agricultural and energy supply chains, including grain, petroleum, and coal. Efficient supply chains can be achieved through decentralized conversion processes that facilitate local sourcing, satellite preprocessing and densification for long-distance transport, and business models that reward biomass growers both nearby and afar. Integrated systems that are cost-effective and energy-efficient will require new ways of thinking about agriculture, energy infrastructure, and rural economic development. Implementing these integrated systems will require innovation and investment in novel technologies, efficient value chains, and socioeconomic and policy frameworks; all are needed to support an expanded biofuels infrastructure that can meet the challenges of scale.

MeSH Categories: Agriculture/economics/methods, *Biofuels/economics, Biomass, Commerce, Costs and Cost Analysis, Economic Development, Industry/economics/instrumentation/methods, *Lignin, Technology, Transportation/economics/methods

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Feedstocks for lignocellulosic biofuels.

Publication Date: 2010 Aug 13 PMID: 20705851
Authors: Somerville, C. - Youngs, H. - Taylor, C. - Davis, S. C. - Long, S. P.
Journal: Science

In 2008, the world produced approximately 87 gigaliters of liquid biofuels, which is roughly equal to the volume of liquid fuel consumed by Germany that year. Essentially, all of this biofuel was produced from crops developed for food production, raising concerns about the net energy and greenhouse gas effects and potential competition between use of land for production of fuels, food, animal feed, fiber, and ecosystem services. The pending implementation of improved technologies to more effectively convert the nonedible parts of plants (lignocellulose) to liquid fuels opens diverse options to use biofuel feedstocks that reach beyond current crops and the land currently used for food and feed. However, there has been relatively little discussion of what types of plants may be useful as bioenergy crops.

MeSH Categories: *Biofuels, Biomass, *Lignin, Poaceae/growth & development/metabolism, Saccharum/growth & development/metabolism, Soil, Water, Wood, Zea mays/growth & development/metabolism

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Out of site.

Publication Date: 2010 Aug 13 PMID: 20705849
Authors: Kintisch, E.
Journal: Science

MeSH Categories: Animal Migration, Animals, *Animals, Wild, *Birds, *Chiroptera, *Energy-Generating Resources, Flight, Animal, Humans, Noise/adverse effects, Radar, *Wind

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Energy's tricky tradeoffs.

Publication Date: 2010 Aug 13 PMID: 20705848
Authors: Cho, A.
Journal: Science

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Is there a road ahead for cellulosic ethanol?

Publication Date: 2010 Aug 13 PMID: 20705847
Authors: Service, R. F.
Journal: Science

MeSH Categories: *Biofuels/economics, *Cellulose/chemistry, Costs and Cost Analysis, *Ethanol, Federal Government, Financing, Government, Public Policy, United States, United States Environmental Protection Agency

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Sending African sunlight to Europe, special delivery.

Publication Date: 2010 Aug 13 PMID: 20705846
Authors: Clery, D.
Journal: Science

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Do we have the energy for the next transition?

Publication Date: 2010 Aug 13 PMID: 20705845
Authors: Kerr, R. A.
Journal: Science

MeSH Categories: Biomass, *Conservation of Energy Resources, *Energy-Generating Resources, Fossil Fuels

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Getting better to get bigger.

Publication Date: 2010 Aug 13 PMID: 20705844
Authors: Malakoff, D. - Yeston, J. - Smith, J.
Journal: Science

MeSH Categories: Biofuels, *Energy-Generating Resources, Fossil Fuels, Nuclear Energy, Solar Energy

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Retrospective. Stephen Schneider (1945-2010).

Publication Date: 2010 Aug 13 PMID: 20705843
Authors: Ehrlich, P. R.
Journal: Science

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Climate Change. The carbon dioxide exchange.

Publication Date: 2010 Aug 13 PMID: 20705842
Authors: Reich, P. B.
Journal: Science

MeSH Categories: Atmosphere, Bacteria/*metabolism, Carbon Dioxide/*metabolism, Cell Respiration, Climate Change, *Ecosystem, Models, Statistical, Mycorrhizae/*metabolism, *Photosynthesis, Plant Leaves/metabolism, Plants/*metabolism, Soil Microbiology, *Temperature

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Engineering. Concentrating on solar electricity and fuels.

Publication Date: 2010 Aug 13 PMID: 20705841
Authors: Roeb, M. - Muller-Steinhagen, H.
Journal: Science

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AIDS/HIV. A boost for HIV vaccine design.

Publication Date: 2010 Aug 13 PMID: 20705840
Authors: Burton, D. R. - Weiss, R. A.
Journal: Science

MeSH Categories: *AIDS Vaccines, Antibodies, Monoclonal/immunology/isolation & purification, Antibodies, Neutralizing/*chemistry/*immunology/isolation & purification, B-Lymphocytes/immunology, Binding Sites, Antibody, Crystallography, X-Ray, Drug Design, Epitopes, HIV Antibodies/*chemistry/*immunology/isolation & purification, HIV Envelope Protein gp120/chemistry/*immunology, HIV Infections/immunology, HIV-1/*immunology, Humans, Protein Engineering

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Geophysics. Sedimentary basins feeling the heat from below.

Publication Date: 2010 Aug 13 PMID: 20705839
Authors: Muller, R. D.
Journal: Science

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Immunology. Beta-catenin balances immunity.

Publication Date: 2010 Aug 13 PMID: 20705838
Authors: Mellman, I. - Clausen, B. E.
Journal: Science

MeSH Categories: Animals, Antigen Presentation, Cytokines/metabolism, Dendritic Cells/*immunology/metabolism, Glycogen Synthase Kinase 3/antagonists & inhibitors/metabolism, Humans, Immunity, Intestinal Mucosa/cytology/*immunology/metabolism, Mice, Models, Immunological, *Self Tolerance, *Signal Transduction, T-Lymphocytes/*immunology, T-Lymphocytes, Regulatory/*immunology, Wnt Proteins/metabolism, beta Catenin/*metabolism

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Cell Biology. The proteome in balance.

Publication Date: 2010 Aug 13 PMID: 20705837
Authors: Hutt, D. - Balch, W. E.
Journal: Science

MeSH Categories: Adenosine Triphosphatases/metabolism, Cell Membrane/*metabolism, Cystic Fibrosis Transmembrane Conductance Regulator/*chemistry/*metabolism, Cytosol/metabolism, Endoplasmic Reticulum/metabolism, HSP70 Heat-Shock Proteins/metabolism, HSP90 Heat-Shock Proteins/metabolism, Homeostasis, Humans, Lysosomes/metabolism, Molecular Chaperones/metabolism, Mutant Proteins/chemistry/metabolism, *Protein Folding, Protein Stability, Protein Transport, Proteome/metabolism, Temperature, Ubiquitin-Conjugating Enzymes/metabolism, Ubiquitin-Protein Ligases/metabolism

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Ecology. Structure and dynamics of ecological networks.

Publication Date: 2010 Aug 13 PMID: 20705836
Authors: Bascompte, J.
Journal: Science

MeSH Categories: Animals, *Ecosystem, Food Chain, Insects/*physiology, Models, Biological, *Plant Physiological Phenomena, Pollination, *Symbiosis

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Nuclear waste: knowledge waste?

Publication Date: 2010 Aug 13 PMID: 20705835
Authors: Rosa, E. A. - Tuler, S. P. - Fischhoff, B. - Webler, T. - Friedman, S. M. - Sclove, R. E. - Shrader-Frechette, K. - English, M. R. - Kasperson, R. E. - Goble, R. L. - Leschine, T. M. - Freudenburg, W. - Chess, C. - Perrow, C. - Erikson, K. - Short, J. F.
Journal: Science

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Science education: mixed messages.

Publication Date: 2010 Aug 13 PMID: 20705834
Authors: Scarbro, H. A.
Journal: Science

MeSH Categories: Humans, *Language, *Linguistics, Science/*education

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Science education: learn by listening.

Publication Date: 2010 Aug 13 PMID: 20705833
Authors: Kessler, P. S.
Journal: Science

MeSH Categories: *Communication, Hearing, Humans, *Language, *Learning, Multilingualism, Science/*education

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Science education: flouting formality.

Publication Date: 2010 Aug 13 PMID: 20705831
Authors: Stewart, M.
Journal: Science

MeSH Categories: Adolescent, Child, Humans, Science/*education, *Textbooks as Topic, *Writing

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Science education: neglected.

Publication Date: 2010 Aug 13 PMID: 20705830
Authors: Calfee, R. - Bruning, R.
Journal: Science

MeSH Categories: Child, Humans, Public Policy, *Reading, Science/*education, Teaching

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Science education: narrative nonfiction.

Publication Date: 2010 Aug 13 PMID: 20705829
Authors: Miller, J.
Journal: Science

MeSH Categories: Humans, *Narration, Science/*education, *Writing

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Science education: poetry.

Publication Date: 2010 Aug 13 PMID: 20705828
Authors: Stewart, A. J.
Journal: Science

MeSH Categories: Humans, *Poetry as Topic, Science/*education

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Paleoclimatology. Climate scientists shine light on cave ice.

Publication Date: 2010 Aug 13 PMID: 20705827
Authors: Laursen, L.
Journal: Science

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Profile: Pauline Wiessner. Anthropologist brings worlds together.

Publication Date: 2010 Aug 13 PMID: 20705826
Authors: Balter, M.
Journal: Science

MeSH Categories: Africa, African Continental Ancestry Group, Anthropology/*history, Cultural Evolution, History, 20th Century, History, 21st Century, Humans, Papua New Guinea, United States

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Human Evolution. Tracing evolution's recent fingerprints.

Publication Date: 2010 Aug 13 PMID: 20705825
Authors: Gibbons, A.
Journal: Science

MeSH Categories: Adaptation, Physiological/*genetics, *Evolution, Gene Frequency, Genetic Techniques, Genetics, Population/*methods, *Genome, Human, Haplotypes, Humans, Models, Genetic, Multifactorial Inheritance, Mutation, *Polymorphism, Single Nucleotide, *Selection, Genetic

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Paleoanthropology. Lucy's toolkit? Old bones may show earliest evidence of tool use.

Publication Date: 2010 Aug 13 PMID: 20705823
Authors: Gibbons, A.
Journal: Science

MeSH Categories: Animals, *Bone and Bones, Ethiopia, Evolution, *Fossils, *Hominidae, Time, *Tool Use Behavior

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Environment. Russia's forest fires ignite concerns about Chornobyl's legacy.

Publication Date: 2010 Aug 13 PMID: 20705822
Authors: Charles, D.
Journal: Science

MeSH Categories: Air Pollutants, Radioactive/*toxicity, *Chernobyl Nuclear Accident, *Fires/prevention & control, Humans, Plutonium/toxicity, Russia, Smoke, *Trees, Ukraine

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Infectious Diseases. Yellow fever mosquito shows up in Northern Europe.

Publication Date: 2010 Aug 13 PMID: 20705820
Authors: Enserink, M.
Journal: Science

MeSH Categories: *Aedes/classification, Animals, *Insect Vectors/classification, Mosquito Control, Netherlands, Population Dynamics

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Gulf Oil Spill. An audacious decision in crisis gets cautious praise.

Publication Date: 2010 Aug 13 PMID: 20705819
Authors: Kintisch, E.
Journal: Science

MeSH Categories: *Accidents, Animals, Atlantic Ocean, Biodegradation, Environmental, *Ecosystem, *Petroleum, *Seawater, *Surface-Active Agents/toxicity, Toxicity Tests, *Water Pollutants

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Gulf Oil Spill. A lot of oil on the loose, not so much to be found.

Publication Date: 2010 Aug 13 PMID: 20705818
Authors: Kerr, R. A.
Journal: Science

MeSH Categories: *Accidents, Atlantic Ocean, Biodegradation, Environmental, *Petroleum/analysis/metabolism, *Seawater/chemistry/microbiology, *Water Pollutants/analysis/metabolism

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Beyond petroleum?

Publication Date: 2010 Aug 13 PMID: 20705817
Authors: Kennedy, D.
Journal: Science

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Dendritic Discrimination of Temporal Input Sequences in Cortical Neurons.

Publication Date: 2010 Aug 12 PMID: 20705816
Authors: Branco, T. - Clark, B. A. - Hausser, M.
Journal: Science

The detection and discrimination of temporal sequences is fundamental to brain function and underlies perception, cognition, and motor output. Applying patterned two-photon glutamate uncaging, we found that single dendrites of cortical pyramidal neurons exhibit sensitivity to the sequence of synaptic activation. This sensitivity is encoded both by local dendritic calcium signals and by somatic depolarization, leading to sequence-selective spike output. The mechanism involves dendritic impedance gradients and nonlinear synaptic NMDA receptor activation and is generalizable to dendrites in different neuronal types. This enables discrimination of patterns delivered to a single dendrite, as well as patterns distributed randomly across the dendritic tree. Pyramidal cell dendrites can thus act as processing compartments for detection of synaptic sequences, implementing a fundamental cortical computation.

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Survivin Reads Phosphorylated Histone H3 Threonine 3 to Activate the Mitotic Kinase Aurora B.

Publication Date: 2010 Aug 12 PMID: 20705815
Authors: Kelly, A. E. - Ghenoiu, C. - Xue, J. Z. - Zierhut, C. - Kimura, H. - Funabiki, H.
Journal: Science

A hallmark of mitosis is the appearance of high levels of histone phosphorylation, yet the roles of these modifications remain largely unknown. Here, we demonstrate that histone H3 phosphorylated at threonine 3 is directly recognized by an evolutionarily conserved binding pocket in the BIR domain of Survivin, a member of the chromosomal passenger complex (CPC). This binding mediates recruitment of the CPC to chromosomes and resulting activation of its kinase subunit Aurora B. Consistently, modulation of the kinase activity of Haspin, which phosphorylates H3T3, leads to defects in the Aurora B-dependent processes of spindle assembly and inhibition of nuclear re-formation. These findings establish a direct cellular role for mitotic histone H3T3 phosphorylation, which is read and translated by the CPC to ensure accurate cell division.

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Detection of a Trailing (L5) Neptune Trojan.

Publication Date: 2010 Aug 12 PMID: 20705814
Authors: Sheppard, S. S. - Trujillo, C. A.
Journal: Science

The orbits of small Solar System bodies record the history of our Solar System. Here, we report the detection of 2008 LC18, which is a Neptune Trojan in the trailing (L5) Lagrangian region of gravitational equilibrium within Neptune's orbit. We estimate that the leading and trailing Neptune Trojan regions have similar sized populations and dynamics with both regions dominated by high inclination objects. Similar populations and dynamics at both Neptune Lagrangian regions indicate the Trojans were likely captured by a migrating, eccentric Neptune in a dynamically excited planetesimal population.

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Pulsar Discovery by Global Volunteer Computing.

Publication Date: 2010 Aug 12 PMID: 20705813
Authors: Knispel, B. - Allen, B. - Cordes, J. M. - Deneva, J. S. - Anderson, D. - Aulbert, C. - Bhat, N. D. - Bock, O. - Bogdanov, S. - Brazier, A. - Camilo, F. - Champion, D. J. - Chatterjee, S. - Crawford, F. - Demorest, P. B. - Fehrmann, H. - Freire, P. C. - Gonzalez, M. E. - Hammer, D. - Hessels, J. W. - Jenet, F. A. - Kasian, L. - Kaspi, V. M. - Kramer, M. - Lazarus, P. - van Leeuwen, J. - Lorimer, D. R. - Lyne, A. G. - Machenschalk, B. - McLaughlin, M. A. - Messenger, C. - Nice, D. J. - Papa, M. A. - Pletsch, H. J. - Prix, R. - Ransom, S. M. - Siemens, X. - Stairs, I. H. - Stappers, B. W. - Stovall, K. - Venkataraman, A.
Journal: Science

Einstein@Home aggregates the computer power of hundreds of thousands of volunteers from 192 countries to "mine" large data sets. It has now found a 40.8-hertz isolated pulsar in radio survey data from the Arecibo Observatory taken in February 2007. Additional timing observations indicate that this pulsar is likely a disrupted recycled pulsar. PSR J2007+2722's pulse profile is remarkably wide with emission over almost the entire spin period; the pulsar likely has closely aligned magnetic and spin axes. The massive computing power provided by volunteers should enable many more such discoveries.

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Histone H3 Thr-3 Phosphorylation by Haspin Positions Aurora B at Centromeres in Mitosis.

Publication Date: 2010 Aug 12 PMID: 20705812
Authors: Wang, F. - Dai, J. - Daum, J. R. - Niedzialkowska, E. - Banerjee, B. - Stukenberg, P. T. - Gorbsky, G. J. - Higgins, J. M.
Journal: Science

Aurora-B is a component of the chromosomal passenger complex (CPC) required for correct spindle-kinetochore attachments during chromosome segregation and for cytokinesis. The chromatin factors that recruit the CPC to centromeres are unknown, however. Here, we show that phosphorylation of histone H3 threonine-3 (H3T3ph) by Haspin is necessary for CPC accumulation at centromeres, and that the CPC subunit Survivin binds directly to H3T3ph. A nonbinding Survivin-D70A/D71A mutant does not support centromeric CPC concentration, and both Haspin depletion and Survivin-D70A/D71A mutation diminish centromere localization of MCAK and mitotic checkpoint signaling in taxol. Survivin-D70A/D71A mutation and microinjection of H3T3ph-specific antibody both compromise centromeric Aurora-B functions but do not prevent cytokinesis. Therefore, H3T3ph generated by Haspin positions the CPC at centromeres to regulate selected targets of Aurora-B during mitosis.

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Nonlinear elasticity and an 8-nm working stroke of single myosin molecules in myofilaments.

Publication Date: 2010 Aug 6 PMID: 20689017
Authors: Kaya, M. - Higuchi, H.
Journal: Science

Using optical trapping and fluorescence imaging techniques, we measured the step size and stiffness of single skeletal myosins interacting with actin filaments and arranged on myosin-rod cofilaments that approximate myosin mechanics during muscle contraction. Stiffness is dramatically lower for negatively compared to positively strained myosins, consistent with buckling of myosin's subfragment 2 rod domain. Low stiffness minimizes drag of negatively strained myosins during contraction at loaded conditions. Myosin's elastic portion is stretched during active force generation, reducing apparent step size with increasing load, even though the working stroke is approximately constant at about 8 nanometers. Taking account of the nonlinear nature of myosin elasticity is essential to relate myosin's internal structural changes to physiological force generation and filament sliding.

MeSH Categories: Actomyosin/chemistry/physiology, Adenosine Diphosphate/metabolism, Adenosine Triphosphate/metabolism, Animals, Compliance, Elasticity, Microfilaments/*physiology, Models, Biological, *Muscle Contraction, Muscle Fibers, Skeletal/chemistry/physiology, Muscle, Skeletal, Myosin Subfragments/physiology, Myosins/chemistry/*physiology, Quantum Dots, Rabbits

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An emerging disease causes regional population collapse of a common North American bat species.

Publication Date: 2010 Aug 6 PMID: 20689016
Authors: Frick, W. F. - Pollock, J. F. - Hicks, A. C. - Langwig, K. E. - Reynolds, D. S. - Turner, G. G. - Butchkoski, C. M. - Kunz, T. H.
Journal: Science

White-nose syndrome (WNS) is an emerging disease affecting hibernating bats in eastern North America that causes mass mortality and precipitous population declines in winter hibernacula. First discovered in 2006 in New York State, WNS is spreading rapidly across eastern North America and currently affects seven species. Mortality associated with WNS is causing a regional population collapse and is predicted to lead to regional extinction of the little brown myotis (Myotis lucifugus), previously one of the most common bat species in North America. Novel diseases can have serious impacts on naive wildlife populations, which in turn can have substantial impacts on ecosystem integrity.

MeSH Categories: Animals, Animals, Wild, *Ascomycota, Canada/epidemiology, Chiroptera/*microbiology/physiology, Communicable Diseases,, Emerging/epidemiology/microbiology/mortality/*veterinary, Dermatomycoses/epidemiology/microbiology/*veterinary, Ecosystem, Extinction, Biological, Hibernation, Models, Statistical, Nonlinear Dynamics, Population Dynamics, Population Surveillance, Stochastic Processes, Syndrome, United States/epidemiology

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Host phylogeny constrains cross-species emergence and establishment of rabies virus in bats.

Publication Date: 2010 Aug 6 PMID: 20689015
Authors: Streicker, D. G. - Turmelle, A. S. - Vonhof, M. J. - Kuzmin, I. V. - McCracken, G. F. - Rupprecht, C. E.
Journal: Science

For RNA viruses, rapid viral evolution and the biological similarity of closely related host species have been proposed as key determinants of the occurrence and long-term outcome of cross-species transmission. Using a data set of hundreds of rabies viruses sampled from 23 North American bat species, we present a general framework to quantify per capita rates of cross-species transmission and reconstruct historical patterns of viral establishment in new host species using molecular sequence data. These estimates demonstrate diminishing frequencies of both cross-species transmission and host shifts with increasing phylogenetic distance between bat species. Evolutionary constraints on viral host range indicate that host species barriers may trump the intrinsic mutability of RNA viruses in determining the fate of emerging host-virus interactions.

MeSH Categories: Animals, Bayes Theorem, Chiroptera/*classification/genetics/*virology, Communicable Diseases, Emerging/transmission/*veterinary/virology, Evolution, Molecular, Genes, Viral, Host-Pathogen Interactions, Likelihood Functions, Molecular Sequence Data, Monte Carlo Method, Nucleocapsid Proteins/genetics, *Phylogeny, Rabies/transmission/*veterinary/virology, Rabies virus/classification/genetics/*pathogenicity/physiology, Species Specificity

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Quantum correlations in optical angle-orbital angular momentum variables.

Publication Date: 2010 Aug 6 PMID: 20689014
Authors: Leach, J. - Jack, B. - Romero, J. - Jha, A. K. - Yao, A. M. - Franke-Arnold, S. - Ireland, D. G. - Boyd, R. W. - Barnett, S. M. - Padgett, M. J.
Journal: Science

Entanglement of the properties of two separated particles constitutes a fundamental signature of quantum mechanics and is a key resource for quantum information science. We demonstrate strong Einstein, Podolsky, and Rosen correlations between the angular position and orbital angular momentum of two photons created by the nonlinear optical process of spontaneous parametric down-conversion. The discrete nature of orbital angular momentum and the continuous but periodic nature of angular position give rise to a special sort of entanglement between these two variables. The resulting correlations are found to be an order of magnitude stronger than those allowed by the uncertainty principle for independent (nonentangled) particles. Our results suggest that angular position and orbital angular momentum may find important applications in quantum information science.

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Massive Dirac fermion on the surface of a magnetically doped topological insulator.

Publication Date: 2010 Aug 6 PMID: 20689013
Authors: Chen, Y. L. - Chu, J. H. - Analytis, J. G. - Liu, Z. K. - Igarashi, K. - Kuo, H. H. - Qi, X. L. - Mo, S. K. - Moore, R. G. - Lu, D. H. - Hashimoto, M. - Sasagawa, T. - Zhang, S. C. - Fisher, I. R. - Hussain, Z. - Shen, Z. X.
Journal: Science

In addition to a bulk energy gap, topological insulators accommodate a conducting, linearly dispersed Dirac surface state. This state is predicted to become massive if time reversal symmetry is broken, and to become insulating if the Fermi energy is positioned inside both the surface and bulk gaps. We introduced magnetic dopants into the three-dimensional topological insulator dibismuth triselenide (Bi2Se3) to break the time reversal symmetry and further position the Fermi energy inside the gaps by simultaneous magnetic and charge doping. The resulting insulating massive Dirac fermion state, which we observed by angle-resolved photoemission, paves the way for studying a range of topological phenomena relevant to both condensed matter and particle physics.

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Normal modes and density of states of disordered colloidal solids.

Publication Date: 2010 Aug 6 PMID: 20689012
Authors: Kaya, D. - Green, N. L. - Maloney, C. E. - Islam, M. F.
Journal: Science

The normal modes and the density of states (DOS) of any material provide a basis for understanding its thermal and mechanical transport properties. In perfect crystals, normal modes are plane waves, but they can be complex in disordered systems. We have experimentally measured normal modes and the DOS in a disordered colloidal crystal. The DOS shows Debye-like behavior at low energies and an excess of modes, or Boson peak, at higher energies. The normal modes take the form of plane waves hybridized with localized short wavelength features in the Debye regime but lose both longitudinal and transverse plane-wave character at a common energy near the Boson peak.

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Role of secondary sensory cortices in emotional memory storage and retrieval in rats.

Publication Date: 2010 Aug 6 PMID: 20689011
Authors: Sacco, T. - Sacchetti, B.
Journal: Science

Visual, acoustic, and olfactory stimuli associated with a highly charged emotional situation take on the affective qualities of that situation. Where the emotional meaning of a given sensory experience is stored is a matter of debate. We found that excitotoxic lesions of auditory, visual, or olfactory secondary sensory cortices impaired remote, but not recent, fear memories in rats. Amnesia was modality-specific and not due to an interference with sensory or emotional processes. In these sites, memory persistence was dependent on ongoing protein kinase Mzeta activity and was associated with an increased activity of layers II-IV, thus suggesting a synaptic strengthening of corticocortical connections. Lesions of the same areas left intact the memory of sensory stimuli not associated with any emotional charge. We propose that secondary sensory cortices support memory storage and retrieval of sensory stimuli that have acquired a behavioral salience with the experience.

MeSH Categories: Acoustic Stimulation, Amnesia/physiopathology, Amygdala/physiology, Animals, Auditory Cortex/*physiology, Conditioning (Psychology), Early Growth Response Protein 1/genetics/metabolism, *Emotions, *Fear, Habituation, Psychophysiologic, Male, Memory/*physiology, Odors, Olfactory Pathways/*physiology, Photic Stimulation, Protein Kinase C/antagonists & inhibitors/metabolism, Rats, Rats, Wistar, Synapses/physiology, Visual Cortex/*physiology

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Vanadium nitrogenase reduces CO.

Publication Date: 2010 Aug 6 PMID: 20689010
Authors: Lee, C. C. - Hu, Y. - Ribbe, M. W.
Journal: Science

Vanadium nitrogenase not only reduces dinitrogen to ammonia but also reduces carbon monoxide to ethylene, ethane, and propane. The parallelism between the two reactions suggests a potential link in mechanism and evolution between the carbon and nitrogen cycles on Earth.

MeSH Categories: Adenosine Triphosphate/metabolism, Azotobacter vinelandii/*enzymology/genetics, Biocatalysis, Carbon Monoxide/*metabolism, Ethane/metabolism, Ethylenes/metabolism, Evolution, Molecular, Genes, Bacterial, Hydrogen/metabolism, Nitrogen/metabolism, Nitrogenase/*metabolism, Oxidation-Reduction, Propane/metabolism

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Developmental biology. Versatile germline genes.

Publication Date: 2010 Aug 6 PMID: 20689009
Authors: Juliano, C. - Wessel, G.
Journal: Science

MeSH Categories: Animals, Cell Lineage, *Embryonic Development, Gastrulation, *Genes, Developmental, Germ Cells/cytology/*physiology, Invertebrates/*embryology/genetics, Multipotent Stem Cells/cytology/physiology, Totipotent Stem Cells/cytology/physiology, Vertebrates/*embryology/genetics

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Physics. In praise of exact quantization.

Publication Date: 2010 Aug 6 PMID: 20689008
Authors: Franz, M.
Journal: Science

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Environmental science. When UV meets fresh water.

Publication Date: 2010 Aug 6 PMID: 20689007
Authors: Williamson, C. E. - Rose, K. C.
Journal: Science

MeSH Categories: Animals, *Ecosystem, Fishes/*physiology, *Fresh Water, Reproduction, *Ultraviolet Rays/adverse effects, Zooplankton/*physiology

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Developmental biology. Which parental gene gets the upper hand?

Publication Date: 2010 Aug 6 PMID: 20689006
Authors: Wilkinson, L. S.
Journal: Science

MeSH Categories: Aging, Animals, Brain/embryology/*physiology, *Epigenesis, Genetic, Evolution, Molecular, Female, Gene Expression Profiling, *Gene Expression Regulation, Developmental, Genetic Association Studies, *Genomic Imprinting, Male, Mice, Sex Characteristics

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Chemistry. The give and take of alcohol activation.

Publication Date: 2010 Aug 6 PMID: 20689005
Authors: Watson, A. J. - Williams, J. M.
Journal: Science

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Epidemiology. Bats, in black and white.

Publication Date: 2010 Aug 6 PMID: 20689004
Authors: Daszak, P.
Journal: Science

MeSH Categories: Animals, Animals, Wild, *Chiroptera/microbiology/virology, Communicable Diseases, Emerging/epidemiology/microbiology/*veterinary, Dermatomycoses/epidemiology/microbiology/transmission/*veterinary, Disease Susceptibility, Extinction, Biological, Host-Pathogen Interactions, Humans, Phylogeny, Population Dynamics, Population Surveillance, RNA Virus Infections/epidemiology/transmission/*veterinary, Rabies/epidemiology/transmission/*veterinary/virology, Species Specificity, Syndrome

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Intellectual property. China's innovation landscape.

Publication Date: 2010 Aug 6 PMID: 20689003
Authors: Huang, K. G.
Journal: Science

MeSH Categories: China, *Diffusion of Innovation, Intellectual Property, *Patents as Topic, Private Sector, *Science, *Technology

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Cuban health care: benefits without costs.

Publication Date: 2010 Aug 6 PMID: 20689002
Authors: Bodenstein, L.
Journal: Science

MeSH Categories: Cuba, *Health Care Costs, Humans, National Health Programs/*economics, United States

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The silver lining of language loss.

Publication Date: 2010 Aug 6 PMID: 20689000
Authors: Heinrich, K. F.
Journal: Science

MeSH Categories: Humans, *Language, Multilingualism

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Cuban health care: consider the source.

Publication Date: 2010 Aug 6 PMID: 20688999
Authors: Hirschfeld, K.
Journal: Science

MeSH Categories: Cuba, *Delivery of Health Care, Health Status, Humans, *National Health Programs

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The time of young scientists.

Publication Date: 2010 Aug 6 PMID: 20688998
Authors: Diamandis, E. P.
Journal: Science

MeSH Categories: Career Mobility, *International Cooperation, *Organizations, *Science

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Profile: Douglas and Pamela Soltis. The power of two.

Publication Date: 2010 Aug 6 PMID: 20688995
Authors: Pennisi, E.
Journal: Science

MeSH Categories: Angiosperms/classification/*genetics, *Evolution, Genes, Plant, Genome, Chloroplast, History, 20th Century, History, 21st Century, Phylogeny, Polyploidy, Tragopogon/classification/*genetics, United States

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Marine biology. Seeing deeply into the sea's biodiversity.

Publication Date: 2010 Aug 6 PMID: 20688994
Authors: Pennisi, E.
Journal: Science

MeSH Categories: Animals, Anthozoa, *Biodiversity, Databases, Factual, Fishes, Oceans and Seas, *Seawater

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Climate change. 'Arctic armageddon' needs more science, less hype.

Publication Date: 2010 Aug 6 PMID: 20688993
Authors: Kerr, R. A.
Journal: Science

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Infectious disease. New map illustrates risk from the 'other' malaria.

Publication Date: 2010 Aug 6 PMID: 20688991
Authors: Vogel, G.
Journal: Science

MeSH Categories: Animals, Climate, Culicidae/parasitology, Duffy Blood-Group System/genetics, *Endemic Diseases, Humans, Immunity, Innate/genetics, Malaria, Vivax/*epidemiology/parasitology/transmission, Maps as Topic, Plasmodium vivax/physiology, Risk Factors

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Energy. Fresh start for fusion project as new leader shakes up management.

Publication Date: 2010 Aug 6 PMID: 20688989
Authors: Travis, J.
Journal: Science

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Physics. Diamond feats give quantum computing a solid boost.

Publication Date: 2010 Aug 6 PMID: 20688988
Authors: Service, R. F.
Journal: Science

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Biosecurity. Defining select agents by DNA sequence.

Publication Date: 2010 Aug 6 PMID: 20688987
Authors: Bhattacharjee, Y.
Journal: Science

MeSH Categories: Base Sequence, Biological Warfare Agents/*classification, Bioterrorism/prevention & control, DNA/*classification/genetics, DNA, Bacterial/classification/genetics, *Security Measures, Virulence/*genetics

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Cancer research. As questions grow, Duke halts trials, launches investigation.

Publication Date: 2010 Aug 6 PMID: 20688986
Authors: Couzin-Frankel, J.
Journal: Science

MeSH Categories: Antineoplastic Agents/pharmacology/*therapeutic use, Biomedical Research/*standards, Cell Line, Tumor, Clinical Trials as Topic, *Gene Expression Profiling, Humans, Neoplasms/*drug therapy/*genetics, North Carolina, Periodicals as Topic, Pharmacogenetics, Publishing, Universities

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Translational ecology.

Publication Date: 2010 Aug 6 PMID: 20688985
Authors: Schlesinger, W. H.
Journal: Science

MeSH Categories: *Ecology, *Ecosystem, *Environment, Interdisciplinary Communication, Policy Making, Societies, Scientific

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Glutamine Deamidation and Dysfunction of Ubiquitin/NEDD8 Induced by a Bacterial Effector Family.

Publication Date: 2010 Aug 5 PMID: 20688984
Authors: Cui, J. - Yao, Q. - Li, S. - Ding, X. - Lu, Q. - Mao, H. - Liu, L. - Zheng, N. - Chen, S. - Shao, F.
Journal: Science

A family of bacterial effectors including CHBP from Burkholderia pseudomallei and Cif from Enteropathogenic Escherichia coli (EPEC) adopt a functionally important papain-like hydrolytic fold. We show here that CHBP was a potent inhibitor of the eukaryotic ubiquitination pathway. CHBP acted as a deamidase that specifically and efficiently deamidated Gln-40 in ubiquitin and ubiquitin-like protein NEDD8 both in vitro and during Burkholderia infection. Deamidated ubiquitin was impaired in supporting ubiquitin-chain synthesis. Cif selectively deamidated NEDD8, which abolished the activity of neddylated Cullin-RING ubiquitin ligases (CRLs). Ubiquitination and ubiquitin-dependent degradation of multiple CRL substrates were impaired by Cif in EPEC-infected cells. Mutations of substrate-contacting residues in Cif abolished or attenuated EPEC-induced cytopathic phenotypes of cell cycle arrest and actin stress fiber formation.

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Strange metal transport realized by gauge/gravity duality.

Publication Date: 2010 Aug 27 PMID: 20688983
Authors: Faulkner, T. - Iqbal, N. - Liu, H. - McGreevy, J. - Vegh, D.
Journal: Science

Fermi liquid theory explains the thermodynamic and transport properties of most metals. The so-called non-Fermi liquids deviate from these expectations and include exotic systems such as the strange metal phase of cuprate superconductors and heavy fermion materials near a quantum phase transition. We used the anti-de-Sitter/conformal field theory correspondence to identify a class of non-Fermi liquids; their low-energy behavior is found to be governed by a nontrivial infrared fixed point, which exhibits nonanalytic scaling behavior only in the time direction. For some representatives of this class, the resistivity has a linear temperature dependence, as is the case for strange metals.

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Structural Basis for Activation of Class Ib Ribonucleotide Reductase.

Publication Date: 2010 Aug 5 PMID: 20688982
Authors: Boal, A. K. - Cotruvo, J. A. Jr - Stubbe, J. - Rosenzweig, A. C.
Journal: Science

The class Ib ribonucleotide reductase of Escherichia coli can initiate reduction of nucleotides to deoxynucleotides with either a Mn(III)(2)-tyrosyl radical (Y*) or a Fe(III)(2)-Y* cofactor in the NrdF subunit. Whereas Fe(III)(2)-Y* can self-assemble from Fe(II)(2)-NrdF and O(2), activation of Mn(II)(2)-NrdF requires a reduced flavoprotein, NrdI, proposed to form the oxidant for cofactor assembly by reduction of O(2). The crystal structures reported here of E. coli Mn(II)(2)-NrdF and Fe(II)(2)-NrdF reveal different coordination environments, suggesting distinct initial binding sites for the oxidants during cofactor activation. In the structures of Mn(II)(2)-NrdF in complex with reduced and oxidized NrdI, a continuous channel connects the NrdI flavin cofactor to the NrdF Mn(II)(2) active site. Crystallographic detection of a putative peroxide in this channel supports the proposed mechanism of Mn(III)(2)-Y* cofactor assembly.

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Aryl Hydrocarbon Receptor Antagonists Promote the Expansion of Human Hematopoietic Stem Cells.

Publication Date: 2010 Aug 5 PMID: 20688981
Authors: Boitano, A. E. - Wang, J. - Romeo, R. - Bouchez, L. C. - Parker, A. E. - Sutton, S. E. - Walker, J. R. - Flaveny, C. A. - Perdew, G. H. - Denison, M. S. - Schultz, P. G. - Cooke, M. P.
Journal: Science

Although practiced clinically for over 40 years, the use of hematopoietic stem cell (HSC) transplants remains limited by the ability to expand these cells ex vivo. An unbiased screen with primary human HSC identified a purine derivative, StemRegenin 1 (SR1), that promotes the ex vivo expansion of CD34(+) cells. Culture of HSC with SR1 led to a 50-fold increase in cells expressing CD34 and a 17-fold increase in cells that retain the ability to engraft immunodeficient mice. Mechanistic studies show that SR1 acts by antagonizing the aryl hydrocarbon receptor (AhR). The identification of SR1 and AhR modulation as a means to induce ex vivo HSC expansion should facilitate the clinical use of HSC therapy.

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The chlorine isotope composition of the moon and implications for an anhydrous mantle.

Publication Date: 2010 Aug 27 PMID: 20688980
Authors: Sharp, Z. D. - Shearer, C. K. - McKeegan, K. D. - Barnes, J. D. - Wang, Y. Q.
Journal: Science

Arguably, the most striking geochemical distinction between Earth and the Moon has been the virtual lack of water (hydrogen) in the latter. This conclusion was recently challenged on the basis of geochemical data from lunar materials that suggest that the Moon's water content might be far higher than previously believed. We measured the chlorine isotope composition of Apollo basalts and glasses and found that the range of isotopic values [from -1 to +24 per mil (per thousand) versus standard mean ocean chloride] is 25 times the range for Earth. The huge isotopic spread is explained by volatilization of metal halides during basalt eruption--a process that could only occur if the Moon had hydrogen concentrations lower than those of Earth by a factor of approximately 10(4) to 10(5), implying that the lunar interior is essentially anhydrous.

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FAN1 acts with FANCI-FANCD2 to promote DNA interstrand cross-link repair.

Publication Date: 2010 Aug 6 PMID: 20671156
Authors: Liu, T. - Ghosal, G. - Yuan, J. - Chen, J. - Huang, J.
Journal: Science

Fanconi anemia (FA) is caused by mutations in 13 Fanc genes and renders cells hypersensitive to DNA interstrand cross-linking (ICL) agents. A central event in the FA pathway is mono-ubiquitylation of the FANCI-FANCD2 (ID) protein complex. Here, we characterize a previously unrecognized nuclease, Fanconi anemia-associated nuclease 1 (FAN1), that promotes ICL repair in a manner strictly dependent on its ability to accumulate at or near sites of DNA damage and that relies on mono-ubiquitylation of the ID complex. Thus, the mono-ubiquitylated ID complex recruits the downstream repair protein FAN1 and facilitates the repair of DNA interstrand cross-links.

MeSH Categories: Amino Acid Sequence, Cell Line, Cell Nucleus/metabolism, DNA/*metabolism, DNA Damage, *DNA Repair, Exodeoxyribonucleases/chemistry/genetics/*metabolism, Fanconi Anemia Complementation Group D2 Protein/*metabolism, Fanconi Anemia Complementation Group Proteins/*metabolism, Gene Knockdown Techniques, Hela Cells, Humans, Mitomycin/pharmacology, Molecular Sequence Data, Mutant Proteins/metabolism, Protein Binding, Ubiquitinated Proteins/metabolism, Ubiquitination, Zinc Fingers

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Quantum oscillations and hall anomaly of surface states in the topological insulator Bi2Te3.

Publication Date: 2010 Aug 13 PMID: 20671155
Authors: Qu, D. X. - Hor, Y. S. - Xiong, J. - Cava, R. J. - Ong, N. P.
Journal: Science

Topological insulators are insulating materials that display massless, Dirac-like surface states in which the electrons have only one spin degree of freedom on each surface. These states have been imaged by photoemission, but little information on their transport parameters, for example, mobility, is available. We report the observation of Shubnikov-de Haas oscillations arising from the surface states in nonmetallic crystals of Bi(2)Te(3). In addition, we uncovered a Hall anomaly in weak fields, which enables the surface current to be seen directly. Both experiments yield a surface mobility (9000 to 10,000 centimeter(2) per volt-second) that is substantially higher than in the bulk. The Fermi velocity of 4 x 10(5) meters per second obtained from these transport experiments agrees with angle-resolved photoemission experiments.

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Land-level changes produced by the Mw 8.8 2010 Chilean earthquake.

Publication Date: 2010 Aug 20 PMID: 20671154
Authors: Farias, M. - Vargas, G. - Tassara, A. - Carretier, S. - Baize, S. - Melnick, D. - Bataille, K.
Journal: Science

We observed vertically displaced coastal and river markers after the 27 February 2010 Chilean earthquake [moment magnitude (Mw) 8.8]. Land-level changes range between 2.5 and -1 meters, evident along an approximately 500-kilometers-long segment identified here as the maximum length of coseismic rupture. A hinge line located 120 kilometers from the trench separates uplifted areas, to the west, from subsided regions. A simple elastic dislocation model fits these observations well; model parameters give a similar seismic moment to seismological estimates and suggest that most of the plate convergence since the 1835 great earthquake was elastically stored and then released during this event.

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PTIP promotes chromatin changes critical for immunoglobulin class switch recombination.

Publication Date: 2010 Aug 20 PMID: 20671152
Authors: Daniel, J. A. - Santos, M. A. - Wang, Z. - Zang, C. - Schwab, K. R. - Jankovic, M. - Filsuf, D. - Chen, H. T. - Gazumyan, A. - Yamane, A. - Cho, Y. W. - Sun, H. W. - Ge, K. - Peng, W. - Nussenzweig, M. C. - Casellas, R. - Dressler, G. R. - Zhao, K. - Nussenzweig, A.
Journal: Science

Programmed genetic rearrangements in lymphocytes require transcription at antigen receptor genes to promote accessibility for initiating double-strand break (DSB) formation critical for DNA recombination and repair. Here, we showed that activated B cells deficient in the PTIP component of the MLL3 (mixed-lineage leukemia 3)-MLL4 complex display impaired trimethylation of histone 3 at lysine 4 (H3K4me3) and transcription initiation of downstream switch regions at the immunoglobulin heavy-chain (Igh) locus, leading to defective immunoglobulin class switching. We also showed that PTIP accumulation at DSBs contributes to class switch recombination (CSR) and genome stability independently of Igh switch transcription. These results demonstrate that PTIP promotes specific chromatin changes that control the accessibility of the Igh locus to CSR and suggest a nonredundant role for the MLL3-MLL4 complex in altering antibody effector function.

MeSH Categories: Animals, Antibody Specificity/genetics, Carrier Proteins/genetics/*physiology, Cytidine Deaminase/metabolism, DNA, Histones/metabolism, Immunoglobulin Class Switching/genetics/*physiology, Immunoglobulin Switch Region, Methylation, Mice, Nuclear Proteins/genetics/*physiology, Promoter Regions, Genetic, Recombination, Genetic, Transcriptional Activation

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The Legionella effector protein DrrA AMPylates the membrane traffic regulator Rab1b.

Publication Date: 2010 Aug 20 PMID: 20651120
Authors: Muller, M. P. - Peters, H. - Blumer, J. - Blankenfeldt, W. - Goody, R. S. - Itzen, A.
Journal: Science

In the course of Legionnaires' disease, the bacterium Legionella pneumophila affects the intracellular vesicular trafficking of infected eukaryotic cells by recruiting the small guanosine triphosphatase (GTPase) Rab1 to the cytosolic face of the Legionella-containing vacuole. In order to accomplish this, the Legionella protein DrrA contains a specific guanine nucleotide exchange activity for Rab1 activation that exchanges guanosine triphosphate (GTP) for guanosine diphosphate on Rab1. We found that the amino-terminal domain of DrrA possesses adenosine monophosphorylation (AMPylation) activity toward the switch II region of Rab1b, leading to posttranslational covalent modification of tyrosine 77. AMPylation of switch II by DrrA restricts the access of GTPase activating proteins, thereby rendering Rab1b constitutively active.

MeSH Categories: Adenosine Monophosphate/*metabolism, Animals, Bacterial Proteins/chemistry/*metabolism/toxicity, COS Cells, Cercopithecus aethiops, Crystallography, Guanine Nucleotide Exchange Factors/chemistry/*metabolism/toxicity, Legionella pneumophila/*physiology, Mass Spectrometry, Models, Molecular, Protein Structure, Tertiary, rab GTP-Binding Proteins/metabolism, rab1 GTP-Binding Proteins/*metabolism

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The Kamil Crater in Egypt.

Publication Date: 2010 Aug 13 PMID: 20651117
Authors: Folco, L. - Di Martino, M. - El Barkooky, A. - D'Orazio, M. - Lethy, A. - Urbini, S. - Nicolosi, I. - Hafez, M. - Cordier, C. - van Ginneken, M. - Zeoli, A. - Radwan, A. M. - El Khrepy, S. - El Gabry, M. - Gomaa, M. - Barakat, A. A. - Serra, R. - El Sharkawi, M.
Journal: Science

We report on the detection in southern Egypt of an impact crater 45 meters in diameter with a pristine rayed structure. Such pristine structures are typically observed on atmosphereless rocky or icy planetary bodies in the solar system. This feature and the association with an iron meteorite impactor and shock metamorphism provides a unique picture of small-scale hypervelocity impacts on Earth's crust. Contrary to current geophysical models, ground data indicate that iron meteorites with masses of the order of tens of tons can penetrate the atmosphere without substantial fragmentation.

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Induction of broadly neutralizing H1N1 influenza antibodies by vaccination.

Publication Date: 2010 Aug 27 PMID: 20647428
Authors: Wei, C. J. - Boyington, J. C. - McTamney, P. M. - Kong, W. P. - Pearce, M. B. - Xu, L. - Andersen, H. - Rao, S. - Tumpey, T. M. - Yang, Z. Y. - Nabel, G. J.
Journal: Science

The rapid dissemination of the 2009 pandemic influenza virus underscores the need for universal influenza vaccines that elicit protective immunity to diverse viral strains. Here, we show that vaccination with plasmid DNA encoding H1N1 influenza hemagglutinin (HA) and boosting with seasonal vaccine or replication-defective adenovirus 5 vector encoding HA stimulated the production of broadly neutralizing influenza antibodies. This prime/boost combination increased the neutralization of diverse H1N1 strains dating from 1934 to 2007 as compared to either component alone and conferred protection against divergent H1N1 viruses in mice and ferrets. These antibodies were directed to the conserved stem region of HA and were also elicited in nonhuman primates. Cross-neutralization of H1N1 subtypes elicited by this approach provides a basis for the development of a universal influenza vaccine for humans.

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Mercury's complex exosphere: results from MESSENGER's third flyby.

Publication Date: 2010 Aug 6 PMID: 20647427
Authors: Vervack, R. J. Jr - McClintock, W. E. - Killen, R. M. - Sprague, A. L. - Anderson, B. J. - Burger, M. H. - Bradley, E. T. - Mouawad, N. - Solomon, S. C. - Izenberg, N. R.
Journal: Science

During MESSENGER's third flyby of Mercury, the Mercury Atmospheric and Surface Composition Spectrometer detected emission from ionized calcium concentrated 1 to 2 Mercury radii tailward of the planet. This measurement provides evidence for tailward magnetospheric convection of photoions produced inside the magnetosphere. Observations of neutral sodium, calcium, and magnesium above the planet's north and south poles reveal altitude distributions that are distinct for each species. A two-component sodium distribution and markedly different magnesium distributions above the two poles are direct indications that multiple processes control the distribution of even single species in Mercury's exosphere.

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Substrate elasticity regulates skeletal muscle stem cell self-renewal in culture.

Publication Date: 2010 Aug 27 PMID: 20647425
Authors: Gilbert, P. M. - Havenstrite, K. L. - Magnusson, K. E. - Sacco, A. - Leonardi, N. A. - Kraft, P. - Nguyen, N. K. - Thrun, S. - Lutolf, M. P. - Blau, H. M.
Journal: Science

Stem cells that naturally reside in adult tissues, such as muscle stem cells (MuSCs), exhibit robust regenerative capacity in vivo that is rapidly lost in culture. Using a bioengineered substrate to recapitulate key biophysical and biochemical niche features in conjunction with a highly automated single-cell tracking algorithm, we show that substrate elasticity is a potent regulator of MuSC fate in culture. Unlike MuSCs on rigid plastic dishes (approximately 10(6) kilopascals), MuSCs cultured on soft hydrogel substrates that mimic the elasticity of muscle (12 kilopascals) self-renew in vitro and contribute extensively to muscle regeneration when subsequently transplanted into mice and assayed histologically and quantitatively by noninvasive bioluminescence imaging. Our studies provide novel evidence that by recapitulating physiological tissue rigidity, propagation of adult muscle stem cells is possible, enabling future cell-based therapies for muscle-wasting diseases.

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Association of trypanolytic ApoL1 variants with kidney disease in African Americans.

Publication Date: 2010 Aug 13 PMID: 20647424
Authors: Genovese, G. - Friedman, D. J. - Ross, M. D. - Lecordier, L. - Uzureau, P. - Freedman, B. I. - Bowden, D. W. - Langefeld, C. D. - Oleksyk, T. K. - Uscinski Knob, A. L. - Bernhardy, A. J. - Hicks, P. J. - Nelson, G. W. - Vanhollebeke, B. - Winkler, C. A. - Kopp, J. B. - Pays, E. - Pollak, M. R.
Journal: Science

African Americans have higher rates of kidney disease than European Americans. Here, we show that, in African Americans, focal segmental glomerulosclerosis (FSGS) and hypertension-attributed end-stage kidney disease (H-ESKD) are associated with two independent sequence variants in the APOL1 gene on chromosome 22 {FSGS odds ratio = 10.5 [95% confidence interval (CI) 6.0 to 18.4]; H-ESKD odds ratio = 7.3 (95% CI 5.6 to 9.5)}. The two APOL1 variants are common in African chromosomes but absent from European chromosomes, and both reside within haplotypes that harbor signatures of positive selection. ApoL1 (apolipoprotein L-1) is a serum factor that lyses trypanosomes. In vitro assays revealed that only the kidney disease-associated ApoL1 variants lysed Trypanosoma brucei rhodesiense. We speculate that evolution of a critical survival factor in Africa may have contributed to the high rates of renal disease in African Americans.

MeSH Categories: Africa, African Americans/*genetics, Alleles, Apolipoproteins/blood/*genetics/metabolism, Case-Control Studies, Cohort Studies, Gene Frequency, Genetic Association Studies, Genetic Predisposition to Disease, Glomerulosclerosis, Focal Segmental/ethnology/*genetics, Haplotypes, Humans, Hypertension/complications, Immunity, Innate, Kidney Failure, Chronic/ethnology/etiology/*genetics, Linkage Disequilibrium, Lipoproteins, HDL/blood/*genetics/metabolism, Logistic Models, Molecular Motor Proteins/genetics, Myosin Heavy Chains/genetics, *Polymorphism, Single Nucleotide, Recombinant Proteins/metabolism, Selection, Genetic, Sequence Deletion, Trypanosoma brucei rhodesiense/*metabolism, Trypanosomiasis, African/genetics/parasitology

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Signaling Kinase AMPK Activates Stress-Promoted Transcription via Histone H2B Phosphorylation.

Publication Date: 2010 Aug 17 PMID: 20647423
Authors: Bungard, D. - Fuerth, B. J. - Zeng, P. Y. - Faubert, B. - Maas, N. L. - Viollet, B. - Carling, D. - Thompson, C. B. - Jones, R. G. - Berger, S. L.
Journal: Science

The mammalian AMP-activated protein kinase (AMPK) is a serine/threonine kinase protein complex that is a central regulator of cellular energy homeostasis (1, 2). However, the mechanisms by which AMPK mediates cellular responses to metabolic stress remain unclear. Here, we demonstrate that AMPK activates transcription through direct association with chromatin and phosphorylation of histone H2B at Serine-36. AMPK recruitment and H2B S36 phosphorylation colocalize within genes activated by AMPK-dependent pathways, and occur both in promoters and transcribed regions. Ectopic expression of S36A-substituted H2B reduces transcription and RNA polymerase II association to AMPK-dependent genes, and lowers cell survival in response to stress. Our results place AMPK-dependent H2B S36 phosphorylation in a direct transcriptional and chromatin regulatory pathway leading to cellular adaptation to stress.

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MESSENGER observations of extreme loading and unloading of Mercury's magnetic tail.

Publication Date: 2010 Aug 6 PMID: 20647422
Authors: Slavin, J. A. - Anderson, B. J. - Baker, D. N. - Benna, M. - Boardsen, S. A. - Gloeckler, G. - Gold, R. E. - Ho, G. C. - Korth, H. - Krimigis, S. M. - McNutt, R. L. Jr - Nittler, L. R. - Raines, J. M. - Sarantos, M. - Schriver, D. - Solomon, S. C. - Starr, R. D. - Travnicek, P. M. - Zurbuchen, T. H.
Journal: Science

During MESSENGER's third flyby of Mercury, the magnetic field in the planet's magnetic tail increased by factors of 2 to 3.5 over intervals of 2 to 3 minutes. Magnetospheric substorms at Earth are powered by similar tail loading, but the amplitude is lower by a factor of approximately 10 and typical durations are approximately 1 hour. The extreme tail loading observed at Mercury implies that the relative intensity of substorms must be much larger than at Earth. The correspondence between the duration of tail field enhancements and the characteristic time for the Dungey cycle, which describes plasma circulation through Mercury's magnetosphere, suggests that such circulation determines the substorm time scale. A key aspect of tail unloading during terrestrial substorms is the acceleration of energetic charged particles, but no acceleration signatures were seen during the MESSENGER flyby.

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Evidence for young volcanism on Mercury from the third MESSENGER flyby.

Publication Date: 2010 Aug 6 PMID: 20647421
Authors: Prockter, L. M. - Ernst, C. M. - Denevi, B. W. - Chapman, C. R. - Head, J. W. 3rd - Fassett, C. I. - Merline, W. J. - Solomon, S. C. - Watters, T. R. - Strom, R. G. - Cremonese, G. - Marchi, S. - Massironi, M.
Journal: Science

During its first two flybys of Mercury, the MESSENGER spacecraft acquired images confirming that pervasive volcanism occurred early in the planet's history. MESSENGER's third Mercury flyby revealed a 290-kilometer-diameter peak-ring impact basin, among the youngest basins yet seen, having an inner floor filled with spectrally distinct smooth plains. These plains are sparsely cratered, postdate the formation of the basin, apparently formed from material that once flowed across the surface, and are therefore interpreted to be volcanic in origin. An irregular depression surrounded by a halo of bright deposits northeast of the basin marks a candidate explosive volcanic vent larger than any previously identified on Mercury. Volcanism on the planet thus spanned a considerable duration, perhaps extending well into the second half of solar system history.

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Long noncoding RNA as modular scaffold of histone modification complexes.

Publication Date: 2010 Aug 6 PMID: 20616235
Authors: Tsai, M. C. - Manor, O. - Wan, Y. - Mosammaparast, N. - Wang, J. K. - Lan, F. - Shi, Y. - Segal, E. - Chang, H. Y.
Journal: Science

Long intergenic noncoding RNAs (lincRNAs) regulate chromatin states and epigenetic inheritance. Here, we show that the lincRNA HOTAIR serves as a scaffold for at least two distinct histone modification complexes. A 5' domain of HOTAIR binds polycomb repressive complex 2 (PRC2), whereas a 3' domain of HOTAIR binds the LSD1/CoREST/REST complex. The ability to tether two distinct complexes enables RNA-mediated assembly of PRC2 and LSD1 and coordinates targeting of PRC2 and LSD1 to chromatin for coupled histone H3 lysine 27 methylation and lysine 4 demethylation. Our results suggest that lincRNAs may serve as scaffolds by providing binding surfaces to assemble select histone modification enzymes, thereby specifying the pattern of histone modifications on target genes.

MeSH Categories: Binding Sites, Carrier Proteins/metabolism, Cell Line, Cells, Cultured, Chromatin/*metabolism, Chromatin Immunoprecipitation, DNA-Binding Proteins/*metabolism, Hela Cells, Histone Demethylases/*metabolism, Histones/*metabolism, Humans, Methylation, Mutation, Nerve Tissue Proteins/metabolism, Nuclear Proteins/metabolism, Nucleic Acid Conformation, Promoter Regions, Genetic, Protein Binding, RNA Interference, RNA, Untranslated/chemistry/*metabolism, Repressor Proteins/*metabolism, Transcription Factors/*metabolism, Transcription, Genetic

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Sex-specific parent-of-origin allelic expression in the mouse brain.

Publication Date: 2010 Aug 6 PMID: 20616234
Authors: Gregg, C. - Zhang, J. - Butler, J. E. - Haig, D. - Dulac, C.
Journal: Science

Genomic imprinting results in preferential gene expression from paternally versus maternally inherited chromosomes. We used a genome-wide approach to uncover sex-specific parent-of-origin allelic effects in the adult mouse brain. Our study identified preferential selection of the maternally inherited X chromosome in glutamatergic neurons of the female cortex. Moreover, analysis of the cortex and hypothalamus identified 347 autosomal genes with sex-specific imprinting features. In the hypothalamus, sex-specific imprinted genes were mostly found in females, which suggests parental influence over the hypothalamic function of daughters. We show that interleukin-18, a gene linked to diseases with sex-specific prevalence, is subject to complex, regional, and sex-specific parental effects in the brain. Parent-of-origin effects thus provide new avenues for investigation of sexual dimorphism in brain function and disease.

MeSH Categories: *Alleles, Animals, Crosses, Genetic, *Epigenesis, Genetic, Female, Gene Expression Profiling, *Genes, X-Linked, *Genomic Imprinting, Glutamic Acid/metabolism, Interleukin-18/genetics, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Mitochondrial Proteins/genetics, Neurons/metabolism, Oxygenases/genetics, Polymorphism, Single Nucleotide, Prefrontal Cortex/cytology/*metabolism, Preoptic Area/cytology/*metabolism, Ribosomal Proteins/genetics, *Sex Characteristics, Succinate Dehydrogenase/genetics, X Chromosome Inactivation

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Rational design of envelope identifies broadly neutralizing human monoclonal antibodies to HIV-1.

Publication Date: 2010 Aug 13 PMID: 20616233
Authors: Wu, X. - Yang, Z. Y. - Li, Y. - Hogerkorp, C. M. - Schief, W. R. - Seaman, M. S. - Zhou, T. - Schmidt, S. D. - Wu, L. - Xu, L. - Longo, N. S. - McKee, K. - O'Dell, S. - Louder, M. K. - Wycuff, D. L. - Feng, Y. - Nason, M. - Doria-Rose, N. - Connors, M. - Kwong, P. D. - Roederer, M. - Wyatt, R. T. - Nabel, G. J. - Mascola, J. R.
Journal: Science

Cross-reactive neutralizing antibodies (NAbs) are found in the sera of many HIV-1-infected individuals, but the virologic basis of their neutralization remains poorly understood. We used knowledge of HIV-1 envelope structure to develop antigenically resurfaced glycoproteins specific for the structurally conserved site of initial CD4 receptor binding. These probes were used to identify sera with NAbs to the CD4-binding site (CD4bs) and to isolate individual B cells from such an HIV-1-infected donor. By expressing immunoglobulin genes from individual cells, we identified three monoclonal antibodies, including a pair of somatic variants that neutralized over 90% of circulating HIV-1 isolates. Exceptionally broad HIV-1 neutralization can be achieved with individual antibodies targeted to the functionally conserved CD4bs of glycoprotein 120, an important insight for future HIV-1 vaccine design.

MeSH Categories: AIDS Vaccines, Antibodies, Monoclonal/*immunology/isolation & purification, Antibodies, Neutralizing/*immunology/isolation & purification, Antibody Specificity, Antigens, CD4/immunology/metabolism, B-Lymphocytes/immunology, Binding Sites, Antibody, Cross Reactions, Drug Design, Enzyme-Linked Immunosorbent Assay, Epitopes/immunology, Genes, Immunoglobulin Heavy Chain, Genes, Immunoglobulin Light Chain, HIV Antibodies/*immunology/isolation & purification, HIV Envelope Protein gp120/chemistry/*immunology/metabolism, HIV Infections/immunology/virology, HIV-1/genetics/*immunology, Humans, Molecular Sequence Data, Neutralization Tests, Protein Engineering, Recombinant Proteins/chemistry/immunology/metabolism

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High-resolution analysis of parent-of-origin allelic expression in the mouse brain.

Publication Date: 2010 Aug 6 PMID: 20616232
Authors: Gregg, C. - Zhang, J. - Weissbourd, B. - Luo, S. - Schroth, G. P. - Haig, D. - Dulac, C.
Journal: Science

Genomic imprinting results in preferential expression of the paternal or maternal allele of certain genes. We have performed a genome-wide characterization of imprinting in the mouse embryonic and adult brain. This approach uncovered parent-of-origin allelic effects of more than 1300 loci. We identified parental bias in the expression of individual genes and of specific transcript isoforms, with differences between brain regions. Many imprinted genes are expressed in neural systems associated with feeding and motivated behaviors, and parental biases preferentially target genetic pathways governing metabolism and cell adhesion. We observed a preferential maternal contribution to gene expression in the developing brain and a major paternal contribution in the adult brain. Thus, parental expression bias emerges as a major mode of epigenetic regulation in the brain.

MeSH Categories: Alleles, Animals, Behavior, Animal, Brain/*embryology/growth & development/*metabolism, Epigenesis, Genetic, Fathers, Female, *Gene Expression, Gene Expression Profiling, Gene Expression Regulation, Developmental, Gene Silencing, *Genomic Imprinting, Male, Mice, Mothers, Multigene Family, Polymorphism, Single Nucleotide, Prefrontal Cortex/embryology/growth & development/metabolism, Preoptic Area/embryology/growth & development/metabolism, Sex Characteristics

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Structural basis for broad and potent neutralization of HIV-1 by antibody VRC01.

Publication Date: 2010 Aug 13 PMID: 20616231
Authors: Zhou, T. - Georgiev, I. - Wu, X. - Yang, Z. Y. - Dai, K. - Finzi, A. - Do Kwon, Y. - Scheid, J. F. - Shi, W. - Xu, L. - Yang, Y. - Zhu, J. - Nussenzweig, M. C. - Sodroski, J. - Shapiro, L. - Nabel, G. J. - Mascola, J. R. - Kwong, P. D.
Journal: Science

During HIV-1 infection, antibodies are generated against the region of the viral gp120 envelope glycoprotein that binds CD4, the primary receptor for HIV-1. Among these antibodies, VRC01 achieves broad neutralization of diverse viral strains. We determined the crystal structure of VRC01 in complex with a human immunodeficiency virus HIV-1 gp120 core. VRC01 partially mimics CD4 interaction with gp120. A shift from the CD4-defined orientation, however, focuses VRC01 onto the vulnerable site of initial CD4 attachment, allowing it to overcome the glycan and conformational masking that diminishes the neutralization potency of most CD4-binding-site antibodies. To achieve this recognition, VRC01 contacts gp120 mainly through immunoglobulin V-gene regions substantially altered from their genomic precursors. Partial receptor mimicry and extensive affinity maturation thus facilitate neutralization of HIV-1 by natural human antibodies.

MeSH Categories: AIDS Vaccines, Amino Acid Sequence, Antibodies, Neutralizing/*chemistry/*immunology, Antibody Affinity, Antigenic Variation, Antigens, CD4/chemistry/immunology/metabolism, Base Sequence, Binding Sites, Antibody, Crystallography, X-Ray, Epitopes/immunology, HIV Antibodies/*chemistry/*immunology, HIV Envelope Protein gp120/chemistry/*immunology/metabolism, HIV-1/*immunology, Humans, Immunoglobulin Fab Fragments/chemistry/immunology/metabolism, Models, Molecular, Molecular Mimicry, Molecular Sequence Data, Neutralization Tests, Protein Conformation, Protein Structure, Tertiary

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Terrestrial gross carbon dioxide uptake: global distribution and covariation with climate.

Publication Date: 2010 Aug 13 PMID: 20603496
Authors: Beer, C. - Reichstein, M. - Tomelleri, E. - Ciais, P. - Jung, M. - Carvalhais, N. - Rodenbeck, C. - Arain, M. A. - Baldocchi, D. - Bonan, G. B. - Bondeau, A. - Cescatti, A. - Lasslop, G. - Lindroth, A. - Lomas, M. - Luyssaert, S. - Margolis, H. - Oleson, K. W. - Roupsard, O. - Veenendaal, E. - Viovy, N. - Williams, C. - Woodward, F. I. - Papale, D.
Journal: Science

Terrestrial gross primary production (GPP) is the largest global CO(2) flux driving several ecosystem functions. We provide an observation-based estimate of this flux at 123 +/- 8 petagrams of carbon per year (Pg C year(-1)) using eddy covariance flux data and various diagnostic models. Tropical forests and savannahs account for 60%. GPP over 40% of the vegetated land is associated with precipitation. State-of-the-art process-oriented biosphere models used for climate predictions exhibit a large between-model variation of GPP's latitudinal patterns and show higher spatial correlations between GPP and precipitation, suggesting the existence of missing processes or feedback mechanisms which attenuate the vegetation response to climate. Our estimates of spatially distributed GPP and its covariation with climate can help improve coupled climate-carbon cycle process models.

MeSH Categories: Artificial Intelligence, Atmosphere, Carbon Dioxide/*metabolism, *Climate, Climatic Processes, *Ecosystem, Geography, Models, Biological, Models, Statistical, Neural Networks (Computer), Oxygen Consumption, *Photosynthesis, Plant Leaves/*metabolism, Plants/*metabolism, Temperature, Trees/metabolism, Uncertainty, Water

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Global convergence in the temperature sensitivity of respiration at ecosystem level.

Publication Date: 2010 Aug 13 PMID: 20603495
Authors: Mahecha, M. D. - Reichstein, M. - Carvalhais, N. - Lasslop, G. - Lange, H. - Seneviratne, S. I. - Vargas, R. - Ammann, C. - Arain, M. A. - Cescatti, A. - Janssens, I. A. - Migliavacca, M. - Montagnani, L. - Richardson, A. D.
Journal: Science

The respiratory release of carbon dioxide (CO(2)) from the land surface is a major flux in the global carbon cycle, antipodal to photosynthetic CO(2) uptake. Understanding the sensitivity of respiratory processes to temperature is central for quantifying the climate-carbon cycle feedback. We approximated the sensitivity of terrestrial ecosystem respiration to air temperature (Q(10)) across 60 FLUXNET sites with the use of a methodology that circumvents confounding effects. Contrary to previous findings, our results suggest that Q(10) is independent of mean annual temperature, does not differ among biomes, and is confined to values around 1.4 +/- 0.1. The strong relation between photosynthesis and respiration, by contrast, is highly variable among sites. The results may partly explain a less pronounced climate-carbon cycle feedback than suggested by current carbon cycle climate models.

MeSH Categories: Carbon/metabolism, Carbon Dioxide/*metabolism, Cell Respiration, *Climate, Ecological and Environmental Processes, *Ecosystem, Models, Biological, Models, Statistical, Photosynthesis, Plants/*metabolism, Soil/analysis, Soil Microbiology, *Temperature

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Peripheral protein quality control removes unfolded CFTR from the plasma membrane.

Publication Date: 2010 Aug 13 PMID: 20595578
Authors: Okiyoneda, T. - Barriere, H. - Bagdany, M. - Rabeh, W. M. - Du, K. - Hohfeld, J. - Young, J. C. - Lukacs, G. L.
Journal: Science

Therapeutic efforts to restore biosynthetic processing of the cystic fibrosis transmembrane conductance regulator lacking the F508 residue (DeltaF508CFTR) are hampered by ubiquitin-dependent lysosomal degradation of nonnative, rescued DeltaF508CFTR from the plasma membrane. Here, functional small interfering RNA screens revealed the contribution of chaperones, cochaperones, and ubiquitin-conjugating and -ligating enzymes to the elimination of unfolded CFTR from the cell surface, as part of a peripheral protein quality-control system. Ubiquitination of nonnative CFTR was required for efficient internalization and lysosomal degradation. This peripheral protein quality-control mechanism probably participates in the preservation of cellular homeostasis by degrading damaged plasma membrane proteins that have escaped from the endoplasmic reticulum quality control or are generated by environmental stresses in situ.

MeSH Categories: Cell Membrane/*metabolism, Cystic Fibrosis Transmembrane Conductance, Regulator/*chemistry/genetics/*metabolism, Glycosylation, HSC70 Heat-Shock Proteins/genetics/metabolism, HSP90 Heat-Shock Proteins/metabolism, Hela Cells, Homeostasis, Humans, Lysosomes/metabolism, Molecular Chaperones/metabolism, Mutant Proteins/chemistry/metabolism, Protein Conformation, *Protein Folding, Protein Stability, Protein Transport, RNA, Small Interfering, Recombinant Proteins/metabolism, Temperature, Ubiquitin-Protein Ligases/genetics/metabolism, Ubiquitinated Proteins/chemistry/metabolism, Ubiquitination

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