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Journal Cover Science
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   ISSN (Print) 0036-8075 - ISSN (Online) 1095-9203
   Published by AAAS Homepage  [6 journals]
  • [Perspective] A matter of tree longevity
    • Authors: Christian Körner
      Abstract: There is much scientific and political interest in using the transfer of carbon from the atmosphere to the biosphere, or carbon sequestration, to help mitigate the greenhouse effect (1). Because plants fix carbon dioxide (CO2) by photosynthesis and store carbon in their body (close to half of plant dry matter is carbon), faster carbon uptake by plants through faster growth is widely held to increase carbon sequestration. Yet, this assumption is supported by neither theory nor evidence. Any gain in carbon storage from faster tree growth will be transitory.Author: Christian Körner
      Keywords: Carbon Sequestration
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2449
       
  • [Policy Forum] The irreversible momentum of clean energy
    • Authors: Barack Obama
      Abstract: The release of carbon dioxide (CO2) and other greenhouse gases (GHGs) due to human activity is increasing global average surface air temperatures, disrupting weather patterns, and acidifying the ocean (1). Left unchecked, the continued growth of GHG emissions could cause global average temperatures to increase by another 4°C or more by 2100 and by 1.5 to 2 times as much in many midcontinent and far northern locations (1). Although our understanding of the impacts of climate change is increasingly and disturbingly clear, there is still debate about the proper course for U.S. policy—a debate that is very much on display during the current presidential transition. But putting near-term politics aside, the mounting economic and scientific evidence leave me confident that trends toward a clean-energy economy that have emerged during my presidency will continue and that the economic opportunity for our country to harness that trend will only grow. This Policy Forum will focus on the four reasons I believe the trend toward clean energy is irreversible.Author: Barack Obama
      Keywords: Climate and Energy
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam6284
       
  • [Policy Forum] The irreversible momentum of clean energy
    • Authors: Barack Obama
      Abstract: The release of carbon dioxide (CO2) and other greenhouse gases (GHGs) due to human activity is increasing global average surface air temperatures, disrupting weather patterns, and acidifying the ocean (1). Left unchecked, the continued growth of GHG emissions could cause global average temperatures to increase by another 4°C or more by 2100 and by 1.5 to 2 times as much in many midcontinent and far northern locations (1). Although our understanding of the impacts of climate change is increasingly and disturbingly clear, there is still debate about the proper course for U.S. policy—a debate that is very much on display during the current presidential transition. But putting near-term politics aside, the mounting economic and scientific evidence leave me confident that trends toward a clean-energy economy that have emerged during my presidency will continue and that the economic opportunity for our country to harness that trend will only grow. This Policy Forum will focus on the four reasons I believe the trend toward clean energy is irreversible.Author: Barack Obama
      Keywords: Climate and Energy
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam6284
       
  • [Report] Plant-soil feedbacks and mycorrhizal type influence temperate
           forest population dynamics
    • Authors: Jonathan A. Bennett
      Abstract: Feedback with soil biota is an important determinant of terrestrial plant diversity. However, the factors regulating plant-soil feedback, which varies from positive to negative among plant species, remain uncertain. In a large-scale study involving 55 species and 550 populations of North American trees, the type of mycorrhizal association explained much of the variation in plant-soil feedbacks. In soil collected beneath conspecifics, arbuscular mycorrhizal trees experienced negative feedback, whereas ectomycorrhizal trees displayed positive feedback. Additionally, arbuscular mycorrhizal trees exhibited strong conspecific inhibition at multiple spatial scales, whereas ectomycorrhizal trees exhibited conspecific facilitation locally and less severe conspecific inhibition regionally. These results suggest that mycorrhizal type, through effects on plant-soil feedbacks, could be an important contributor to population regulation and community structure in temperate forests.
      Authors : Jonathan A. Bennett, Hafiz Maherali, Kurt O. Reinhart, Ylva Lekberg, Miranda M. Hart, John Klironomos
      PubDate: 2017-01-13
      DOI: 10.1126/science.aai8212
       
  • [Report] Superficial layers of the medial entorhinal cortex replay
           independently of the hippocampus
    • Authors: J. O’Neill
      Abstract: The hippocampus is thought to initiate systems-wide mnemonic processes through the reactivation of previously acquired spatial and episodic memory traces, which can recruit the entorhinal cortex as a first stage of memory redistribution to other brain areas. Hippocampal reactivation occurs during sharp wave–ripples, in which synchronous network firing encodes sequences of places. We investigated the coordination of this replay by recording assembly activity simultaneously in the CA1 region of the hippocampus and superficial layers of the medial entorhinal cortex. We found that entorhinal cell assemblies can replay trajectories independently of the hippocampus and sharp wave–ripples. This suggests that the hippocampus is not the sole initiator of spatial and episodic memory trace reactivation. Memory systems involved in these processes may include nonhierarchical, parallel components.
      Authors : J. O’Neill, C.N. Boccara, F. Stella, P. Schoenenberger, J. Csicsvari
      PubDate: 2017-01-13
      DOI: 10.1126/science.aag2787
       
  • [Report] Plant-soil feedbacks and mycorrhizal type influence temperate
           forest population dynamics
    • Authors: Jonathan A. Bennett
      Abstract: Feedback with soil biota is an important determinant of terrestrial plant diversity. However, the factors regulating plant-soil feedback, which varies from positive to negative among plant species, remain uncertain. In a large-scale study involving 55 species and 550 populations of North American trees, the type of mycorrhizal association explained much of the variation in plant-soil feedbacks. In soil collected beneath conspecifics, arbuscular mycorrhizal trees experienced negative feedback, whereas ectomycorrhizal trees displayed positive feedback. Additionally, arbuscular mycorrhizal trees exhibited strong conspecific inhibition at multiple spatial scales, whereas ectomycorrhizal trees exhibited conspecific facilitation locally and less severe conspecific inhibition regionally. These results suggest that mycorrhizal type, through effects on plant-soil feedbacks, could be an important contributor to population regulation and community structure in temperate forests.
      Authors : Jonathan A. Bennett, Hafiz Maherali, Kurt O. Reinhart, Ylva Lekberg, Miranda M. Hart, John Klironomos
      PubDate: 2017-01-13
      DOI: 10.1126/science.aai8212
       
  • [Technical Response] Response to Comment on “Ribose and related sugars
           from ultraviolet irradiation of interstellar ice analogs”
    • Authors: Cornelia Meinert
      Abstract: We detected ribose and related sugars in the organic residues of simulated interstellar ices using multidimensional gas chromatography. Kawai questions the formation of sugar compounds in the ices and suggests that they arise from a classical formose reaction during sample workup for analysis. We disagree with this hypothesis and present additional data to argue that Kawai’s criticism does not apply.
      Authors : Cornelia Meinert, Iuliia Myrgorodska, Pierre de Marcellus, Thomas Buhse, Laurent Nahon, Søren V. Hoffmann, Louis Le Sergeant d’Hendecourt, Uwe J. Meierhenrich
      PubDate: 2017-01-13
      DOI: 10.1126/science.aah3756
       
  • [This Week in Science] Better living through water-splitting
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Electrochemistry
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-i
       
  • [This Week in Science] A machine for building ribosomes
    • Authors: Guy Riddihough
      Abstract: Author: Guy Riddihough
      Keywords: Ribosome Assembly
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-j
       
  • [This Week in Science] A machine for building ribosomes
    • Authors: Guy Riddihough
      Abstract: Author: Guy Riddihough
      Keywords: Ribosome Assembly
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-j
       
  • [This Week in Science] Squeezing out the oddness
    • Authors: Jelena Stajic
      Abstract: Author: Jelena Stajic
      Keywords: Superconductivity
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-k
       
  • [This Week in Science] Squeezing out the oddness
    • Authors: Jelena Stajic
      Abstract: Author: Jelena Stajic
      Keywords: Superconductivity
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-k
       
  • [In Depth] NASA missions aim at asteroid oddballs
    • Authors: Paul Voosen
      Abstract: On 4 January, the agency picked two $450 million missions for Discovery, its low-cost planetary program, and, like several recent probes, both target small bodies. Set for a 2021 launch, Lucy will fly past Jupiter's Trojan asteroids, which share the gas giant's orbit but precede and follow it. Two years later, Psyche will set out for a rare iron and nickel asteroid of the same name. Little is known about Lucy's targets, but the Trojans appear to be too diverse to be simply leftovers from Jupiter's formation. Psyche will orbit the stripped-bare, metallic core of an embryonic planet. The selection of two missions helps the Discovery program get back on track after delays to its most recent selection, the InSight probe to Mars.Author: Paul Voosen
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.117-a
       
  • [In Depth] Pioneering study images activity in fetal brains
    • Authors: Greg Miller
      Abstract: Babies born prematurely are prone to problems later in life—they're more likely to develop autism or attention deficit hyperactivity disorder, and more likely to struggle in school. A new study that's among the first to investigate brain activity in human fetuses suggests that the underlying neurological issues may begin in the womb. The research, led by Moriah Thomason, a developmental neuroscientist at Wayne State University School of Medicine in Detroit, Michigan, and published this week in Scientific Reports, provides the first direct evidence of altered brain function in fetuses that go on to be born prematurely. Thomason and others hope the work might ultimately point to ways to remediate or even prevent such early injuries.Author: Greg Miller
      Keywords: Neuroscience
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.117-b
       
  • [In Depth] Pioneering study images activity in fetal brains
    • Authors: Greg Miller
      Abstract: Babies born prematurely are prone to problems later in life—they're more likely to develop autism or attention deficit hyperactivity disorder, and more likely to struggle in school. A new study that's among the first to investigate brain activity in human fetuses suggests that the underlying neurological issues may begin in the womb. The research, led by Moriah Thomason, a developmental neuroscientist at Wayne State University School of Medicine in Detroit, Michigan, and published this week in Scientific Reports, provides the first direct evidence of altered brain function in fetuses that go on to be born prematurely. Thomason and others hope the work might ultimately point to ways to remediate or even prevent such early injuries.Author: Greg Miller
      Keywords: Neuroscience
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.117-b
       
  • [In Depth] Life-saving diphtheria drug is running out
    • Authors: Kai Kupferschmidt
      Abstract: Two children have died in Europe in the past 2 years because they suffered from diphtheria and did not get an antiserum that neutralizes the deadly toxin produced by Corynebacterium diphtheriae in time. The antitoxin, produced in horses, is in short supply worldwide; the market is too small to make production profitable. The European Center for Disease Control and Prevention is planning to highlight the shortage in a report expected early in 2017 that will also address Europe's diagnostic capacity for diphtheria. Meanwhile, researchers are trying to make the antitoxin in cell culture, which could help shore up production and improve quality.Author: Kai Kupferschmidt
      Keywords: Infectious Diseases
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.118
       
  • [Report] Vectorial representation of spatial goals in the hippocampus of
           bats
    • Authors: Ayelet Sarel
      Abstract: To navigate, animals need to represent not only their own position and orientation, but also the location of their goal. Neural representations of an animal’s own position and orientation have been extensively studied. However, it is unknown how navigational goals are encoded in the brain. We recorded from hippocampal CA1 neurons of bats flying in complex trajectories toward a spatial goal. We discovered a subpopulation of neurons with angular tuning to the goal direction. Many of these neurons were tuned to an occluded goal, suggesting that goal-direction representation is memory-based. We also found cells that encoded the distance to the goal, often in conjunction with goal direction. The goal-direction and goal-distance signals make up a vectorial representation of spatial goals, suggesting a previously unrecognized neuronal mechanism for goal-directed navigation.
      Authors : Ayelet Sarel, Arseny Finkelstein, Liora Las, Nachum Ulanovsky
      PubDate: 2017-01-13
      DOI: 10.1126/science.aak9589
       
  • [Report] Plant-soil feedback and the maintenance of diversity in
           Mediterranean-climate shrublands
    • Authors: François P. Teste
      Abstract: Soil biota influence plant performance through plant-soil feedback, but it is unclear whether the strength of such feedback depends on plant traits and whether plant-soil feedback drives local plant diversity. We grew 16 co-occurring plant species with contrasting nutrient-acquisition strategies from hyperdiverse Australian shrublands and exposed them to soil biota from under their own or other plant species. Plant responses to soil biota varied according to their nutrient-acquisition strategy, including positive feedback for ectomycorrhizal plants and negative feedback for nitrogen-fixing and nonmycorrhizal plants. Simulations revealed that such strategy-dependent feedback is sufficient to maintain the high taxonomic and functional diversity characterizing these Mediterranean-climate shrublands. Our study identifies nutrient-acquisition strategy as a key trait explaining how different plant responses to soil biota promote local plant diversity.
      Authors : François P. Teste, Paul Kardol, Benjamin L. Turner, David A. Wardle, Graham Zemunik, Michael Renton, Etienne Laliberté
      PubDate: 2017-01-13
      DOI: 10.1126/science.aai8291
       
  • [Report] Vectorial representation of spatial goals in the hippocampus of
           bats
    • Authors: Ayelet Sarel
      Abstract: To navigate, animals need to represent not only their own position and orientation, but also the location of their goal. Neural representations of an animal’s own position and orientation have been extensively studied. However, it is unknown how navigational goals are encoded in the brain. We recorded from hippocampal CA1 neurons of bats flying in complex trajectories toward a spatial goal. We discovered a subpopulation of neurons with angular tuning to the goal direction. Many of these neurons were tuned to an occluded goal, suggesting that goal-direction representation is memory-based. We also found cells that encoded the distance to the goal, often in conjunction with goal direction. The goal-direction and goal-distance signals make up a vectorial representation of spatial goals, suggesting a previously unrecognized neuronal mechanism for goal-directed navigation.
      Authors : Ayelet Sarel, Arseny Finkelstein, Liora Las, Nachum Ulanovsky
      PubDate: 2017-01-13
      DOI: 10.1126/science.aak9589
       
  • [Technical Comment] Comment on “Ribose and related sugars from
           ultraviolet irradiation of interstellar ice analogs”
    • Authors: Jun Kawai
      Abstract: Meinert et al. (Reports, 8 April 2016, p. 208) reported the formation of prebiotic molecules, including ribose, in an interstellar ice analog experiment. We show that if their experimental procedure is accurately described, much or most of their products may have been formed during their analysis process, not in the parent ice.Author: Jun Kawai
      PubDate: 2017-01-13
      DOI: 10.1126/science.aag2990
       
  • [Letter] Pipelines imperil Canada's ecosystem
    • Authors: Juan José Alava
      Abstract:
      Authors : Juan José Alava, Nastenka Calle
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam5609
       
  • [Technical Comment] Comment on “Ribose and related sugars from
           ultraviolet irradiation of interstellar ice analogs”
    • Authors: Jun Kawai
      Abstract: Meinert et al. (Reports, 8 April 2016, p. 208) reported the formation of prebiotic molecules, including ribose, in an interstellar ice analog experiment. We show that if their experimental procedure is accurately described, much or most of their products may have been formed during their analysis process, not in the parent ice.Author: Jun Kawai
      PubDate: 2017-01-13
      DOI: 10.1126/science.aag2990
       
  • [Letter] Europe's biodiversity avoids fatal setback
    • Authors: Arie Trouwborst
      Abstract:
      Authors : Arie Trouwborst, Guillaume Chapron, Floor Fleurke, Yaffa Epstein, José Vicente López-Bao
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam6200
       
  • [Letter] Europe's biodiversity avoids fatal setback
    • Authors: Arie Trouwborst
      Abstract:
      Authors : Arie Trouwborst, Guillaume Chapron, Floor Fleurke, Yaffa Epstein, José Vicente López-Bao
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam6200
       
  • [Letter] Pipelines imperil Canada's ecosystem
    • Authors: Juan José Alava
      Abstract:
      Authors : Juan José Alava, Nastenka Calle
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam5609
       
  • [Report] Pyocyanin degradation by a tautomerizing demethylase inhibits
           Pseudomonas aeruginosa biofilms
    • Authors: Kyle C. Costa
      Abstract: The opportunistic pathogen Pseudomonas aeruginosa produces colorful redox-active metabolites called phenazines, which underpin biofilm development, virulence, and clinical outcomes. Although phenazines exist in many forms, the best studied is pyocyanin. Here, we describe pyocyanin demethylase (PodA), a hitherto uncharacterized protein that oxidizes the pyocyanin methyl group to formaldehyde and reduces the pyrazine ring via an unusual tautomerizing demethylation reaction. Treatment with PodA disrupts P. aeruginosa biofilm formation similarly to DNase, suggesting interference with the pyocyanin-dependent release of extracellular DNA into the matrix. PodA-dependent pyocyanin demethylation also restricts established biofilm aggregate populations experiencing anoxic conditions. Together, these results show that modulating extracellular redox-active metabolites can influence the fitness of a biofilm-forming microorganism.
      Authors : Kyle C. Costa, Nathaniel R. Glasser, Stuart J. Conway, Dianne K. Newman
      PubDate: 2017-01-13
      DOI: 10.1126/science.aag3180
       
  • [Report] Plant-soil feedback and the maintenance of diversity in
           Mediterranean-climate shrublands
    • Authors: François P. Teste
      Abstract: Soil biota influence plant performance through plant-soil feedback, but it is unclear whether the strength of such feedback depends on plant traits and whether plant-soil feedback drives local plant diversity. We grew 16 co-occurring plant species with contrasting nutrient-acquisition strategies from hyperdiverse Australian shrublands and exposed them to soil biota from under their own or other plant species. Plant responses to soil biota varied according to their nutrient-acquisition strategy, including positive feedback for ectomycorrhizal plants and negative feedback for nitrogen-fixing and nonmycorrhizal plants. Simulations revealed that such strategy-dependent feedback is sufficient to maintain the high taxonomic and functional diversity characterizing these Mediterranean-climate shrublands. Our study identifies nutrient-acquisition strategy as a key trait explaining how different plant responses to soil biota promote local plant diversity.
      Authors : François P. Teste, Paul Kardol, Benjamin L. Turner, David A. Wardle, Graham Zemunik, Michael Renton, Etienne Laliberté
      PubDate: 2017-01-13
      DOI: 10.1126/science.aai8291
       
  • [Feature] Fateful imprints
    • Authors: Jennifer Couzin-Frankel
      Abstract: Imprinting means that in some places along the human genome—about 100 genes in all—the way DNA behaves depends on which parent passes it to the offspring. Some of the genes in sperm and egg cells have chemicals called methyl molecules that attach to them, a process called methylation; these molecules can either activate or silence a gene. In some cases, the mother's copy of the gene is activated, and the father's silenced. In others the opposite is true. The function of each of the dozens of human imprinted genes isn't yet known, but many appear to guide metabolism and growth prior to birth. When imprinting goes awry—and researchers don't understand yet why that happens—the outcome can be health problems in the baby. The last several years have seen imprinting disorders emerge from the shadows, and with them a deeper appreciation for the human genome's ability to modulate gene expression in the earliest stages of development. Scientists are also considering how imprinting errors could cause cancer or stunt fetal growth.Author: Jennifer Couzin-Frankel
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.122
       
  • [Feature] Fateful imprints
    • Authors: Jennifer Couzin-Frankel
      Abstract: Imprinting means that in some places along the human genome—about 100 genes in all—the way DNA behaves depends on which parent passes it to the offspring. Some of the genes in sperm and egg cells have chemicals called methyl molecules that attach to them, a process called methylation; these molecules can either activate or silence a gene. In some cases, the mother's copy of the gene is activated, and the father's silenced. In others the opposite is true. The function of each of the dozens of human imprinted genes isn't yet known, but many appear to guide metabolism and growth prior to birth. When imprinting goes awry—and researchers don't understand yet why that happens—the outcome can be health problems in the baby. The last several years have seen imprinting disorders emerge from the shadows, and with them a deeper appreciation for the human genome's ability to modulate gene expression in the earliest stages of development. Scientists are also considering how imprinting errors could cause cancer or stunt fetal growth.Author: Jennifer Couzin-Frankel
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.122
       
  • [In Depth] Birds don't need exercise to stay fit for epic flights
    • Authors: Elizabeth Pennisi
      Abstract: Anyone who rose morning after morning this week for an exhausting and ache-generating exercise class to fulfill a New Year's resolution will envy the bar-headed goose. The bird has the strength and endurance to fly 4000 kilometers over the Himalayas without having to do a lick of exercise to prepare. Reported last week at the annual meeting of the Society for Integrative and Comparative Biology, the goose study is one of several examples of birds that can, in effect, get up from the couch ready to run a marathon—a painful contrast to humans, with our need for regular exercise to stay in shape. They may be able to avoid training because their bodies are so well adapted to make sure enough oxygen gets to their muscles. And extra exercise can have a downside, work in zebra finches shows. More work needs to be done, however, to determine whether any other animals are like us and need to use it or lose it when it comes to being fit.Author: Elizabeth Pennisi
      Keywords: Physiology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.121
       
  • [In Depth] Birds don't need exercise to stay fit for epic flights
    • Authors: Elizabeth Pennisi
      Abstract: Anyone who rose morning after morning this week for an exhausting and ache-generating exercise class to fulfill a New Year's resolution will envy the bar-headed goose. The bird has the strength and endurance to fly 4000 kilometers over the Himalayas without having to do a lick of exercise to prepare. Reported last week at the annual meeting of the Society for Integrative and Comparative Biology, the goose study is one of several examples of birds that can, in effect, get up from the couch ready to run a marathon—a painful contrast to humans, with our need for regular exercise to stay in shape. They may be able to avoid training because their bodies are so well adapted to make sure enough oxygen gets to their muscles. And extra exercise can have a downside, work in zebra finches shows. More work needs to be done, however, to determine whether any other animals are like us and need to use it or lose it when it comes to being fit.Author: Elizabeth Pennisi
      Keywords: Physiology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.121
       
  • [In Depth] Observations hint at a new recipe for giant black holes
    • Authors: Joshua Sokol
      Abstract: Astronomers have glimpsed a new solution to a long-standing puzzle: how black holes could have grown fast enough to explain the monsters a billion times the mass of the sun seen soon after the big bang. Most black holes are thought to start out as collapsed stars, but they grow too slowly to fit the bill. Instead, theorists have suggested, the behemoth black holes in the early universe could have gotten a head start when huge gas clouds left by the big bang quickly shrank under their own gravity and condensed into black hole seeds 10 thousand to 100 thousand times heavier than the sun. Those seeds would have grown further by sucking in stars and gas. Last week, at the American Astronomical Society meeting in Grapevine, Texas, astronomers reported hints of such "direct collapse" black holes in x-ray and infrared surveys of the early universe.Author: Joshua Sokol
      Keywords: Astrophysics
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.120
       
  • [In Depth] Life-saving diphtheria drug is running out
    • Authors: Kai Kupferschmidt
      Abstract: Two children have died in Europe in the past 2 years because they suffered from diphtheria and did not get an antiserum that neutralizes the deadly toxin produced by Corynebacterium diphtheriae in time. The antitoxin, produced in horses, is in short supply worldwide; the market is too small to make production profitable. The European Center for Disease Control and Prevention is planning to highlight the shortage in a report expected early in 2017 that will also address Europe's diagnostic capacity for diphtheria. Meanwhile, researchers are trying to make the antitoxin in cell culture, which could help shore up production and improve quality.Author: Kai Kupferschmidt
      Keywords: Infectious Diseases
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.118
       
  • [In Depth] Observations hint at a new recipe for giant black holes
    • Authors: Joshua Sokol
      Abstract: Astronomers have glimpsed a new solution to a long-standing puzzle: how black holes could have grown fast enough to explain the monsters a billion times the mass of the sun seen soon after the big bang. Most black holes are thought to start out as collapsed stars, but they grow too slowly to fit the bill. Instead, theorists have suggested, the behemoth black holes in the early universe could have gotten a head start when huge gas clouds left by the big bang quickly shrank under their own gravity and condensed into black hole seeds 10 thousand to 100 thousand times heavier than the sun. Those seeds would have grown further by sucking in stars and gas. Last week, at the American Astronomical Society meeting in Grapevine, Texas, astronomers reported hints of such "direct collapse" black holes in x-ray and infrared surveys of the early universe.Author: Joshua Sokol
      Keywords: Astrophysics
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.120
       
  • [In Depth] Expedition probes ocean trench's deepest secrets
    • Authors: Jane Qiu
      Abstract: The Mariana Trench, a scythe-shaped cleft in the western Pacific sea floor, plunges nearly 11 kilometers—deeper than any other place in the oceans. The trench marks a subduction zone, where one slab of crust slides beneath another. But whereas many other subducting plates slope gradually downward, in the Mariana the Pacific Plate dives nearly vertically. Scientists have long wondered what accounts for that precipitous dive, and why massive earthquakes that generate long-ranging tsunamis at other subduction zones have not been recorded in the trench. Now, a Chinese-U.S. team has planted an array of seismometers on the Mariana's slopes. By listening for seismic waves, the 5-year, $12 million Mariana Trench initiative aims to image in fine detail the warped rock layers in and around the trench, looking for clues as to what shapes them.Author: Jane Qiu
      Keywords: Geophysics
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.115
       
  • [In Depth] Jilted again, Venus scientists pine for their neglected planet
    • Authors: Paul Voosen
      Abstract: A probe from NASA has not targeted Venus, Earth's closest neighbor in solar system, since the early 1990s, although missions to Mars continue to pile up. Scientists had thought it likely that NASA would select a Venus mission for its next low-cost planetary probe, but on 4 January the agency selected two projects targeting asteroids instead. There are a host of scientific questions to be answered about Venus's origins, potential active volcanism, and hints of primordial oceans, but the planet's crushing pressure and veil of clouds may simply make it too risky for $450 million missions. Scientists are now targeting NASA's next competition, for a more expensive Venus lander, with bids due in April.Author: Paul Voosen
      Keywords: Planetary Science
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.116
       
  • [In Depth] Jilted again, Venus scientists pine for their neglected planet
    • Authors: Paul Voosen
      Abstract: A probe from NASA has not targeted Venus, Earth's closest neighbor in solar system, since the early 1990s, although missions to Mars continue to pile up. Scientists had thought it likely that NASA would select a Venus mission for its next low-cost planetary probe, but on 4 January the agency selected two projects targeting asteroids instead. There are a host of scientific questions to be answered about Venus's origins, potential active volcanism, and hints of primordial oceans, but the planet's crushing pressure and veil of clouds may simply make it too risky for $450 million missions. Scientists are now targeting NASA's next competition, for a more expensive Venus lander, with bids due in April.Author: Paul Voosen
      Keywords: Planetary Science
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.116
       
  • [In Depth] NASA missions aim at asteroid oddballs
    • Authors: Paul Voosen
      Abstract: On 4 January, the agency picked two $450 million missions for Discovery, its low-cost planetary program, and, like several recent probes, both target small bodies. Set for a 2021 launch, Lucy will fly past Jupiter's Trojan asteroids, which share the gas giant's orbit but precede and follow it. Two years later, Psyche will set out for a rare iron and nickel asteroid of the same name. Little is known about Lucy's targets, but the Trojans appear to be too diverse to be simply leftovers from Jupiter's formation. Psyche will orbit the stripped-bare, metallic core of an embryonic planet. The selection of two missions helps the Discovery program get back on track after delays to its most recent selection, the InSight probe to Mars.Author: Paul Voosen
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.117-a
       
  • [In Depth] Expedition probes ocean trench's deepest secrets
    • Authors: Jane Qiu
      Abstract: The Mariana Trench, a scythe-shaped cleft in the western Pacific sea floor, plunges nearly 11 kilometers—deeper than any other place in the oceans. The trench marks a subduction zone, where one slab of crust slides beneath another. But whereas many other subducting plates slope gradually downward, in the Mariana the Pacific Plate dives nearly vertically. Scientists have long wondered what accounts for that precipitous dive, and why massive earthquakes that generate long-ranging tsunamis at other subduction zones have not been recorded in the trench. Now, a Chinese-U.S. team has planted an array of seismometers on the Mariana's slopes. By listening for seismic waves, the 5-year, $12 million Mariana Trench initiative aims to image in fine detail the warped rock layers in and around the trench, looking for clues as to what shapes them.Author: Jane Qiu
      Keywords: Geophysics
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.115
       
  • [Report] Hydrogen positions in single nanocrystals revealed by electron
           diffraction
    • Authors: L. Palatinus
      Abstract: The localization of hydrogen atoms is an essential part of crystal structure analysis, but it is difficult because of their small scattering power. We report the direct localization of hydrogen atoms in nanocrystalline materials, achieved using the recently developed approach of dynamical refinement of precession electron diffraction tomography data. We used this method to locate hydrogen atoms in both an organic (paracetamol) and an inorganic (framework cobalt aluminophosphate) material. The results demonstrate that the technique can reliably reveal fine structural details, including the positions of hydrogen atoms in single crystals with micro- to nanosized dimensions.
      Authors : L. Palatinus, P. Brázda, P. Boullay, O. Perez, M. Klementová, S. Petit, V. Eigner, M. Zaarour, S. Mintova
      PubDate: 2017-01-13
      DOI: 10.1126/science.aak9652
       
  • [Report] Pyocyanin degradation by a tautomerizing demethylase inhibits
           Pseudomonas aeruginosa biofilms
    • Authors: Kyle C. Costa
      Abstract: The opportunistic pathogen Pseudomonas aeruginosa produces colorful redox-active metabolites called phenazines, which underpin biofilm development, virulence, and clinical outcomes. Although phenazines exist in many forms, the best studied is pyocyanin. Here, we describe pyocyanin demethylase (PodA), a hitherto uncharacterized protein that oxidizes the pyocyanin methyl group to formaldehyde and reduces the pyrazine ring via an unusual tautomerizing demethylation reaction. Treatment with PodA disrupts P. aeruginosa biofilm formation similarly to DNase, suggesting interference with the pyocyanin-dependent release of extracellular DNA into the matrix. PodA-dependent pyocyanin demethylation also restricts established biofilm aggregate populations experiencing anoxic conditions. Together, these results show that modulating extracellular redox-active metabolites can influence the fitness of a biofilm-forming microorganism.
      Authors : Kyle C. Costa, Nathaniel R. Glasser, Stuart J. Conway, Dianne K. Newman
      PubDate: 2017-01-13
      DOI: 10.1126/science.aag3180
       
  • [Report] Macrocyclic bis-thioureas catalyze stereospecific glycosylation
           reactions
    • Authors: Yongho Park
      Abstract: Carbohydrates are involved in nearly all aspects of biochemistry, but their complex chemical structures present long-standing practical challenges to their synthesis. In particular, stereochemical outcomes in glycosylation reactions are highly dependent on the steric and electronic properties of coupling partners; thus, carbohydrate synthesis is not easily predictable. Here we report the discovery of a macrocyclic bis-thiourea derivative that catalyzes stereospecific invertive substitution pathways of glycosyl chlorides. The utility of the catalyst is demonstrated in the synthesis of trans-1,2-, cis-1,2-, and 2-deoxy-β-glycosides. Mechanistic studies are consistent with a cooperative mechanism in which an electrophile and a nucleophile are simultaneously activated to effect a stereospecific substitution reaction.
      Authors : Yongho Park, Kaid C. Harper, Nadine Kuhl, Eugene E. Kwan, Richard Y. Liu, Eric N. Jacobsen
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal1875
       
  • [Report] Hydrogen positions in single nanocrystals revealed by electron
           diffraction
    • Authors: L. Palatinus
      Abstract: The localization of hydrogen atoms is an essential part of crystal structure analysis, but it is difficult because of their small scattering power. We report the direct localization of hydrogen atoms in nanocrystalline materials, achieved using the recently developed approach of dynamical refinement of precession electron diffraction tomography data. We used this method to locate hydrogen atoms in both an organic (paracetamol) and an inorganic (framework cobalt aluminophosphate) material. The results demonstrate that the technique can reliably reveal fine structural details, including the positions of hydrogen atoms in single crystals with micro- to nanosized dimensions.
      Authors : L. Palatinus, P. Brázda, P. Boullay, O. Perez, M. Klementová, S. Petit, V. Eigner, M. Zaarour, S. Mintova
      PubDate: 2017-01-13
      DOI: 10.1126/science.aak9652
       
  • [In Brief] News at a glance
    • Abstract: In science news around the world, U.S. officials release a plan to help agencies decide whether to fund controversial studies that make viruses more dangerous, a new survey of U.K. academics finds that 90% still think universities will be harmed by the country's departure from the European Union, members of the U.S. Congress call for a ban on federal funding of research with fetal tissue donated after elective abortions, internet entrepreneur Yuri Milner's Breakthrough Starshot initiative signs up for telescope time at the European Southern Observatory to get a better look at its target, the Alpha Centauri system, and more. Also, PLOS ONE is poised to lose its title as the world's largest peer-reviewed journal to another open-access publication, Scientific Reports, published by Springer Nature. And scientists explore the many unusual skills of the eellike hagfish, from surviving shark bites to tying itself into knots to tear apart its prey.
      Keywords: SCI COMMUN
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.112
       
  • [Report] Macrocyclic bis-thioureas catalyze stereospecific glycosylation
           reactions
    • Authors: Yongho Park
      Abstract: Carbohydrates are involved in nearly all aspects of biochemistry, but their complex chemical structures present long-standing practical challenges to their synthesis. In particular, stereochemical outcomes in glycosylation reactions are highly dependent on the steric and electronic properties of coupling partners; thus, carbohydrate synthesis is not easily predictable. Here we report the discovery of a macrocyclic bis-thiourea derivative that catalyzes stereospecific invertive substitution pathways of glycosyl chlorides. The utility of the catalyst is demonstrated in the synthesis of trans-1,2-, cis-1,2-, and 2-deoxy-β-glycosides. Mechanistic studies are consistent with a cooperative mechanism in which an electrophile and a nucleophile are simultaneously activated to effect a stereospecific substitution reaction.
      Authors : Yongho Park, Kaid C. Harper, Nadine Kuhl, Eugene E. Kwan, Richard Y. Liu, Eric N. Jacobsen
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal1875
       
  • [Report] Braiding a molecular knot with eight crossings
    • Authors: Jonathan J. Danon
      Abstract: Knots may ultimately prove just as versatile and useful at the nanoscale as at the macroscale. However, the lack of synthetic routes to all but the simplest molecular knots currently prevents systematic investigation of the influence of knotting at the molecular level. We found that it is possible to assemble four building blocks into three braided ligand strands. Octahedral iron(II) ions control the relative positions of the three strands at each crossing point in a circular triple helicate, while structural constraints on the ligands determine the braiding connections. This approach enables two-step assembly of a molecular 819 knot featuring eight nonalternating crossings in a 192-atom closed loop ~20 nanometers in length. The resolved metal-free 819 knot enantiomers have pronounced features in their circular dichroism spectra resulting solely from topological chirality.
      Authors : Jonathan J. Danon, Anneke Krüger, David A. Leigh, Jean-François Lemonnier, Alexander J. Stephens, Iñigo J. Vitorica-Yrezabal, Steffen L. Woltering
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal1619
       
  • [Report] Braiding a molecular knot with eight crossings
    • Authors: Jonathan J. Danon
      Abstract: Knots may ultimately prove just as versatile and useful at the nanoscale as at the macroscale. However, the lack of synthetic routes to all but the simplest molecular knots currently prevents systematic investigation of the influence of knotting at the molecular level. We found that it is possible to assemble four building blocks into three braided ligand strands. Octahedral iron(II) ions control the relative positions of the three strands at each crossing point in a circular triple helicate, while structural constraints on the ligands determine the braiding connections. This approach enables two-step assembly of a molecular 819 knot featuring eight nonalternating crossings in a 192-atom closed loop ~20 nanometers in length. The resolved metal-free 819 knot enantiomers have pronounced features in their circular dichroism spectra resulting solely from topological chirality.
      Authors : Jonathan J. Danon, Anneke Krüger, David A. Leigh, Jean-François Lemonnier, Alexander J. Stephens, Iñigo J. Vitorica-Yrezabal, Steffen L. Woltering
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal1619
       
  • [Report] Strong coupling of a single electron in silicon to a microwave
           photon
    • Authors: X. Mi
      Abstract: Silicon is vital to the computing industry because of the high quality of its native oxide and well-established doping technologies. Isotopic purification has enabled quantum coherence times on the order of seconds, thereby placing silicon at the forefront of efforts to create a solid-state quantum processor. We demonstrate strong coupling of a single electron in a silicon double quantum dot to the photonic field of a microwave cavity, as shown by the observation of vacuum Rabi splitting. Strong coupling of a quantum dot electron to a cavity photon would allow for long-range qubit coupling and the long-range entanglement of electrons in semiconductor quantum dots.
      Authors : X. Mi, J. V. Cady, D. M. Zajac, P. W. Deelman, J. R. Petta
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2469
       
  • [Report] Strong coupling of a single electron in silicon to a microwave
           photon
    • Authors: X. Mi
      Abstract: Silicon is vital to the computing industry because of the high quality of its native oxide and well-established doping technologies. Isotopic purification has enabled quantum coherence times on the order of seconds, thereby placing silicon at the forefront of efforts to create a solid-state quantum processor. We demonstrate strong coupling of a single electron in a silicon double quantum dot to the photonic field of a microwave cavity, as shown by the observation of vacuum Rabi splitting. Strong coupling of a quantum dot electron to a cavity photon would allow for long-range qubit coupling and the long-range entanglement of electrons in semiconductor quantum dots.
      Authors : X. Mi, J. V. Cady, D. M. Zajac, P. W. Deelman, J. R. Petta
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2469
       
  • [Research Article] Structure of a yeast step II catalytically activated
           spliceosome
    • Authors: Chuangye Yan
      Abstract: Each cycle of precursor messenger RNA (pre-mRNA) splicing comprises two sequential reactions, first freeing the 5′ exon and generating an intron lariat–3′ exon and then ligating the two exons and releasing the intron lariat. The second reaction is executed by the step II catalytically activated spliceosome (known as the C* complex). Here, we present the cryo–electron microscopy structure of a C* complex from Saccharomyces cerevisiae at an average resolution of 4.0 angstroms. Compared with the preceding spliceosomal complex (C complex), the lariat junction has been translocated by 15 to 20 angstroms to vacate space for the incoming 3′-exon sequences. The step I splicing factors Cwc25 and Yju2 have been dissociated from the active site. Two catalytic motifs from Prp8 (the 1585 loop and the β finger of the ribonuclease H–like domain), along with the step II splicing factors Prp17 and Prp18 and other surrounding proteins, are poised to assist the second transesterification. These structural features, together with those reported for other spliceosomal complexes, yield a near-complete mechanistic picture on the splicing cycle.
      Authors : Chuangye Yan, Ruixue Wan, Rui Bai, Gaoxingyu Huang, Yigong Shi
      PubDate: 2017-01-13
      DOI: 10.1126/science.aak9979
       
  • [This Week in Science] Prions enter another domain of life
    • Authors: Stella M. Hurtley
      Abstract: Author: Stella M. Hurtley
      Keywords: Bacterial Prions
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-g
       
  • [This Week in Science] Channeling pain through GPCRs
    • Authors: Nancy R. Gough
      Abstract: Author: Nancy R. Gough
      Keywords: Neuroscience
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-h
       
  • [This Week in Science] Channeling pain through GPCRs
    • Authors: Nancy R. Gough
      Abstract: Author: Nancy R. Gough
      Keywords: Neuroscience
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-h
       
  • [This Week in Science] Better living through water-splitting
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Electrochemistry
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-i
       
  • [This Week in Science] Inducing strong coupling
    • Authors: Ian S. Osborne
      Abstract: Author: Ian S. Osborne
      Keywords: Quantum Electronics
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-e
       
  • [This Week in Science] Inducing strong coupling
    • Authors: Ian S. Osborne
      Abstract: Author: Ian S. Osborne
      Keywords: Quantum Electronics
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-e
       
  • [This Week in Science] Phages build themselves a wall
    • Authors: Stella M. Hurtley
      Abstract: Author: Stella M. Hurtley
      Keywords: Cell Biology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-f
       
  • [This Week in Science] Phages build themselves a wall
    • Authors: Stella M. Hurtley
      Abstract: Author: Stella M. Hurtley
      Keywords: Cell Biology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-f
       
  • [This Week in Science] Prions enter another domain of life
    • Authors: Stella M. Hurtley
      Abstract: Author: Stella M. Hurtley
      Keywords: Bacterial Prions
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-g
       
  • [This Week in Science] Poised for the second step of splicing
    • Authors: Valda Vinson
      Abstract: Author: Valda Vinson
      Keywords: Structural Biology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-d
       
  • [This Week in Science] Poised for the second step of splicing
    • Authors: Valda Vinson
      Abstract: Author: Valda Vinson
      Keywords: Structural Biology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-d
       
  • [This Week in Science] Designing proteins with cavities
    • Authors: Valda Vinson
      Abstract: Author: Valda Vinson
      Keywords: Protein Design
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-b
       
  • [This Week in Science] Designing proteins with cavities
    • Authors: Valda Vinson
      Abstract: Author: Valda Vinson
      Keywords: Protein Design
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-b
       
  • [This Week in Science] Initiating an antitumor attack
    • Authors: Yevgeniya Nusinovich
      Abstract: Author: Yevgeniya Nusinovich
      Keywords: Cancer
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-c
       
  • [This Week in Science] Initiating an antitumor attack
    • Authors: Yevgeniya Nusinovich
      Abstract: Author: Yevgeniya Nusinovich
      Keywords: Cancer
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-c
       
  • [Letter] A big, bug science party
    • Authors: Cara M. Gibson
      Abstract: Author: Cara M. Gibson
      Keywords: Outside the Tower
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam6439
       
  • [Letter] A big, bug science party
    • Authors: Cara M. Gibson
      Abstract: Author: Cara M. Gibson
      Keywords: Outside the Tower
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam6439
       
  • [This Week in Science] Are you aware how well you remember?
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Brain Research
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-a
       
  • [This Week in Science] Are you aware how well you remember?
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Brain Research
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-a
       
  • [Technical Response] Response to Comment on “Ribose and related sugars
           from ultraviolet irradiation of interstellar ice analogs”
    • Authors: Cornelia Meinert
      Abstract: We detected ribose and related sugars in the organic residues of simulated interstellar ices using multidimensional gas chromatography. Kawai questions the formation of sugar compounds in the ices and suggests that they arise from a classical formose reaction during sample workup for analysis. We disagree with this hypothesis and present additional data to argue that Kawai’s criticism does not apply.
      Authors : Cornelia Meinert, Iuliia Myrgorodska, Pierre de Marcellus, Thomas Buhse, Laurent Nahon, Søren V. Hoffmann, Louis Le Sergeant d’Hendecourt, Uwe J. Meierhenrich
      PubDate: 2017-01-13
      DOI: 10.1126/science.aah3756
       
  • [Editors' Choice] Observing peculiar vortices
    • Authors: Jelena Stajic
      Abstract: Author: Jelena Stajic
      Keywords: Quantum Fluids
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-b
       
  • [Editors' Choice] Fast point-of-care detection of biomarkers
    • Authors: Julia Fahrenkamp-Uppenbrink
      Abstract: Author: Julia Fahrenkamp-Uppenbrink
      Keywords: Medical Diagnostics
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-c
       
  • [Editors' Choice] Fast point-of-care detection of biomarkers
    • Authors: Julia Fahrenkamp-Uppenbrink
      Abstract: Author: Julia Fahrenkamp-Uppenbrink
      Keywords: Medical Diagnostics
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-c
       
  • [Editors' Choice] Cancer and nerves: A tuf(t) partnership
    • Authors: Paula A. Kiberstis
      Abstract: Author: Paula A. Kiberstis
      Keywords: Cancer Biology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-d
       
  • [Editors' Choice] Cancer and nerves: A tuf(t) partnership
    • Authors: Paula A. Kiberstis
      Abstract: Author: Paula A. Kiberstis
      Keywords: Cancer Biology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-d
       
  • [Editors' Choice] Did Phaethon father the Geminids?
    • Authors: Keith T. Smith
      Abstract: Author: Keith T. Smith
      Keywords: Meteoroid Streams
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-e
       
  • [Editors' Choice] Did Phaethon father the Geminids?
    • Authors: Keith T. Smith
      Abstract: Author: Keith T. Smith
      Keywords: Meteoroid Streams
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-e
       
  • [Editors' Choice] Gut communities form a history of connection
    • Authors: Caroline Ash
      Abstract: Author: Caroline Ash
      Keywords: Microbiota
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-f
       
  • [Editors' Choice] Gut communities form a history of connection
    • Authors: Caroline Ash
      Abstract: Author: Caroline Ash
      Keywords: Microbiota
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-f
       
  • [Editors' Choice] Speedy sperm
    • Authors: Sacha Vignieri
      Abstract: Author: Sacha Vignieri
      Keywords: Sperm Competition
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-g
       
  • [Editors' Choice] Speedy sperm
    • Authors: Sacha Vignieri
      Abstract: Author: Sacha Vignieri
      Keywords: Sperm Competition
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-g
       
  • [Research Article] Structure of a yeast step II catalytically activated
           spliceosome
    • Authors: Chuangye Yan
      Abstract: Each cycle of precursor messenger RNA (pre-mRNA) splicing comprises two sequential reactions, first freeing the 5′ exon and generating an intron lariat–3′ exon and then ligating the two exons and releasing the intron lariat. The second reaction is executed by the step II catalytically activated spliceosome (known as the C* complex). Here, we present the cryo–electron microscopy structure of a C* complex from Saccharomyces cerevisiae at an average resolution of 4.0 angstroms. Compared with the preceding spliceosomal complex (C complex), the lariat junction has been translocated by 15 to 20 angstroms to vacate space for the incoming 3′-exon sequences. The step I splicing factors Cwc25 and Yju2 have been dissociated from the active site. Two catalytic motifs from Prp8 (the 1585 loop and the β finger of the ribonuclease H–like domain), along with the step II splicing factors Prp17 and Prp18 and other surrounding proteins, are poised to assist the second transesterification. These structural features, together with those reported for other spliceosomal complexes, yield a near-complete mechanistic picture on the splicing cycle.
      Authors : Chuangye Yan, Ruixue Wan, Rui Bai, Gaoxingyu Huang, Yigong Shi
      PubDate: 2017-01-13
      DOI: 10.1126/science.aak9979
       
  • [Review] Combining theory and experiment in electrocatalysis: Insights
           into materials design
    • Authors: Zhi Wei Seh
      Abstract: Electrocatalysis plays a central role in clean energy conversion, enabling a number of sustainable processes for future technologies. This review discusses design strategies for state-of-the-art heterogeneous electrocatalysts and associated materials for several different electrochemical transformations involving water, hydrogen, and oxygen, using theory as a means to rationalize catalyst performance. By examining the common principles that govern catalysis for different electrochemical reactions, we describe a systematic framework that clarifies trends in catalyzing these reactions, serving as a guide to new catalyst development while highlighting key gaps that need to be addressed. We conclude by extending this framework to emerging clean energy reactions such as hydrogen peroxide production, carbon dioxide reduction, and nitrogen reduction, where the development of improved catalysts could allow for the sustainable production of a broad range of fuels and chemicals.
      Authors : Zhi Wei Seh, Jakob Kibsgaard, Colin F. Dickens, Ib Chorkendorff, Jens K. Nørskov, Thomas F. Jaramillo
      PubDate: 2017-01-13
      DOI: 10.1126/science.aad4998
       
  • [Research Article] Strong peak in Tc of Sr2RuO4 under uniaxial pressure
    • Authors: Alexander Steppke
      Abstract: Sr2RuO4 is an unconventional superconductor that has attracted widespread study because of its high purity and the possibility that its superconducting order parameter has odd parity. We study the dependence of its superconductivity on anisotropic strain. Applying uniaxial pressures of up to ~1 gigapascals along a 〈100〉 direction (a axis) of the crystal lattice results in the transition temperature (Tc) increasing from 1.5 kelvin in the unstrained material to 3.4 kelvin at compression by ≈0.6%, and then falling steeply. Calculations give evidence that the observed maximum Tc occurs at or near a Lifshitz transition when the Fermi level passes through a Van Hove singularity, and open the possibility that the highly strained, Tc = 3.4 K Sr2RuO4 has an even-parity, rather than an odd-parity, order parameter.
      Authors : Alexander Steppke, Lishan Zhao, Mark E. Barber, Thomas Scaffidi, Fabian Jerzembeck, Helge Rosner, Alexandra S. Gibbs, Yoshiteru Maeno, Steven H. Simon, Andrew P. Mackenzie, Clifford W. Hicks
      PubDate: 2017-01-13
      DOI: 10.1126/science.aaf9398
       
  • [Research Article] Strong peak in Tc of Sr2RuO4 under uniaxial pressure
    • Authors: Alexander Steppke
      Abstract: Sr2RuO4 is an unconventional superconductor that has attracted widespread study because of its high purity and the possibility that its superconducting order parameter has odd parity. We study the dependence of its superconductivity on anisotropic strain. Applying uniaxial pressures of up to ~1 gigapascals along a 〈100〉 direction (a axis) of the crystal lattice results in the transition temperature (Tc) increasing from 1.5 kelvin in the unstrained material to 3.4 kelvin at compression by ≈0.6%, and then falling steeply. Calculations give evidence that the observed maximum Tc occurs at or near a Lifshitz transition when the Fermi level passes through a Van Hove singularity, and open the possibility that the highly strained, Tc = 3.4 K Sr2RuO4 has an even-parity, rather than an odd-parity, order parameter.
      Authors : Alexander Steppke, Lishan Zhao, Mark E. Barber, Thomas Scaffidi, Fabian Jerzembeck, Helge Rosner, Alexandra S. Gibbs, Yoshiteru Maeno, Steven H. Simon, Andrew P. Mackenzie, Clifford W. Hicks
      PubDate: 2017-01-13
      DOI: 10.1126/science.aaf9398
       
  • [Editorial] Global clean energy in 2017
    • Authors: David King
      Abstract: During the November 2016 Climate Change Conference in Marrakesh, much talk centered on implementation of the political commitments made in Paris in 2015. Governments are now focused on putting their words into action as they prepare for the first official stocktake in 2018. Innovation will have an essential role to play.Author: David King
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam7088
       
  • [This Week in Science] More light on dopamine receptors
    • Authors: Philip Yeagle
      Abstract: Author: Philip Yeagle
      Keywords: Neurophysiology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-s
       
  • [This Week in Science] TAMpering with tumors
    • Authors: Angela Colmone
      Abstract: Author: Angela Colmone
      Keywords: Immunotherapy
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-t
       
  • [This Week in Science] TAMpering with tumors
    • Authors: Angela Colmone
      Abstract: Author: Angela Colmone
      Keywords: Immunotherapy
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-t
       
  • [This Week in Science] Three strands ironed closely together
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Molecular Knots
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-u
       
  • [This Week in Science] Three strands ironed closely together
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Molecular Knots
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-u
       
  • [Editors' Choice] Effects of drought on tree performance
    • Authors: Andrew M. Sugden
      Abstract: Author: Andrew M. Sugden
      Keywords: Plants and Climate
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-a
       
  • [Editors' Choice] Effects of drought on tree performance
    • Authors: Andrew M. Sugden
      Abstract: Author: Andrew M. Sugden
      Keywords: Plants and Climate
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-a
       
  • [Editors' Choice] Observing peculiar vortices
    • Authors: Jelena Stajic
      Abstract: Author: Jelena Stajic
      Keywords: Quantum Fluids
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.144-b
       
  • [This Week in Science] How to get to place B
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Brain Research
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-p
       
  • [This Week in Science] How to get to place B
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Brain Research
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-p
       
  • [This Week in Science] Parallel computation in memory-making
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Memory Processing
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-q
       
  • [This Week in Science] Parallel computation in memory-making
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Memory Processing
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-q
       
  • [This Week in Science] Faster tree growth is no panacea
    • Authors: Julia Fahrenkamp-Uppenbrink
      Abstract: Author: Julia Fahrenkamp-Uppenbrink
      Keywords: Climate Change
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-r
       
  • [This Week in Science] Faster tree growth is no panacea
    • Authors: Julia Fahrenkamp-Uppenbrink
      Abstract: Author: Julia Fahrenkamp-Uppenbrink
      Keywords: Climate Change
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-r
       
  • [This Week in Science] More light on dopamine receptors
    • Authors: Philip Yeagle
      Abstract: Author: Philip Yeagle
      Keywords: Neurophysiology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-s
       
  • [This Week in Science] A cyclic catalyst to pair up sugars
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Organic Chemistry
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-l
       
  • [This Week in Science] A cyclic catalyst to pair up sugars
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Organic Chemistry
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-l
       
  • [This Week in Science] Pin the tail on the hydrogens
    • Authors: Marc S. Lavine
      Abstract: Author: Marc S. Lavine
      Keywords: Materials Science
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-m
       
  • [This Week in Science] Pin the tail on the hydrogens
    • Authors: Marc S. Lavine
      Abstract: Author: Marc S. Lavine
      Keywords: Materials Science
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-m
       
  • [This Week in Science] Redox metabolite role in biofilms
    • Authors: Caroline Ash
      Abstract: Author: Caroline Ash
      Keywords: Structural Biology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-n
       
  • [This Week in Science] Redox metabolite role in biofilms
    • Authors: Caroline Ash
      Abstract: Author: Caroline Ash
      Keywords: Structural Biology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-n
       
  • [This Week in Science] Soil biota and plant diversity
    • Authors: Andrew M. Sugden
      Abstract: Author: Andrew M. Sugden
      Keywords: Plant Ecology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-o
       
  • [This Week in Science] Soil biota and plant diversity
    • Authors: Andrew M. Sugden
      Abstract: Author: Andrew M. Sugden
      Keywords: Plant Ecology
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.143-o
       
  • [Review] Combining theory and experiment in electrocatalysis: Insights
           into materials design
    • Authors: Zhi Wei Seh
      Abstract: Electrocatalysis plays a central role in clean energy conversion, enabling a number of sustainable processes for future technologies. This review discusses design strategies for state-of-the-art heterogeneous electrocatalysts and associated materials for several different electrochemical transformations involving water, hydrogen, and oxygen, using theory as a means to rationalize catalyst performance. By examining the common principles that govern catalysis for different electrochemical reactions, we describe a systematic framework that clarifies trends in catalyzing these reactions, serving as a guide to new catalyst development while highlighting key gaps that need to be addressed. We conclude by extending this framework to emerging clean energy reactions such as hydrogen peroxide production, carbon dioxide reduction, and nitrogen reduction, where the development of improved catalysts could allow for the sustainable production of a broad range of fuels and chemicals.
      Authors : Zhi Wei Seh, Jakob Kibsgaard, Colin F. Dickens, Ib Chorkendorff, Jens K. Nørskov, Thomas F. Jaramillo
      PubDate: 2017-01-13
      DOI: 10.1126/science.aad4998
       
  • [Editorial] Global clean energy in 2017
    • Authors: David King
      Abstract: During the November 2016 Climate Change Conference in Marrakesh, much talk centered on implementation of the political commitments made in Paris in 2015. Governments are now focused on putting their words into action as they prepare for the first official stocktake in 2018. Innovation will have an essential role to play.Author: David King
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam7088
       
  • [In Brief] News at a glance
    • Abstract: In science news around the world, U.S. officials release a plan to help agencies decide whether to fund controversial studies that make viruses more dangerous, a new survey of U.K. academics finds that 90% still think universities will be harmed by the country's departure from the European Union, members of the U.S. Congress call for a ban on federal funding of research with fetal tissue donated after elective abortions, internet entrepreneur Yuri Milner's Breakthrough Starshot initiative signs up for telescope time at the European Southern Observatory to get a better look at its target, the Alpha Centauri system, and more. Also, PLOS ONE is poised to lose its title as the world's largest peer-reviewed journal to another open-access publication, Scientific Reports, published by Springer Nature. And scientists explore the many unusual skills of the eellike hagfish, from surviving shark bites to tying itself into knots to tear apart its prey.
      Keywords: SCI COMMUN
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.112
       
  • [Errata] Erratum for the Letter “Response to ‘Forest value: More than
           commercial’” by C. B. Barrett, M. Zhou, P. B. Reich, T. W. Crowther,
           J. Liang
    • PubDate: 2017-01-13
      DOI: 10.1126/science.aam7177
       
  • [Errata] Erratum for the Letter “Response to ‘Forest value: More than
           commercial’” by C. B. Barrett, M. Zhou, P. B. Reich, T. W. Crowther,
           J. Liang
    • PubDate: 2017-01-13
      DOI: 10.1126/science.aam7177
       
  • [Research Article] Architecture of the yeast small subunit processome
    • Authors: Malik Chaker-Margot
      Abstract: The small subunit (SSU) processome, a large ribonucleoprotein particle, organizes the assembly of the eukaryotic small ribosomal subunit by coordinating the folding, cleavage, and modification of nascent pre–ribosomal RNA (rRNA). Here, we present the cryo–electron microscopy structure of the yeast SSU processome at 5.1-angstrom resolution. The structure reveals how large ribosome biogenesis complexes assist the 5′ external transcribed spacer and U3 small nucleolar RNA in providing an intertwined RNA-protein assembly platform for the separate maturation of 18S rRNA domains. The strategic placement of a molecular motor at the center of the particle further suggests a mechanism for mediating conformational changes within this giant particle. This study provides a structural framework for a mechanistic understanding of eukaryotic ribosome assembly in the model organism Saccharomyces cerevisiae.
      Authors : Malik Chaker-Margot, Jonas Barandun, Mirjam Hunziker, Sebastian Klinge
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal1880
       
  • [Research Article] Architecture of the yeast small subunit processome
    • Authors: Malik Chaker-Margot
      Abstract: The small subunit (SSU) processome, a large ribonucleoprotein particle, organizes the assembly of the eukaryotic small ribosomal subunit by coordinating the folding, cleavage, and modification of nascent pre–ribosomal RNA (rRNA). Here, we present the cryo–electron microscopy structure of the yeast SSU processome at 5.1-angstrom resolution. The structure reveals how large ribosome biogenesis complexes assist the 5′ external transcribed spacer and U3 small nucleolar RNA in providing an intertwined RNA-protein assembly platform for the separate maturation of 18S rRNA domains. The strategic placement of a molecular motor at the center of the particle further suggests a mechanism for mediating conformational changes within this giant particle. This study provides a structural framework for a mechanistic understanding of eukaryotic ribosome assembly in the model organism Saccharomyces cerevisiae.
      Authors : Malik Chaker-Margot, Jonas Barandun, Mirjam Hunziker, Sebastian Klinge
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal1880
       
  • [Book Review] Travels through time
    • Authors: Christopher Kemp
      Abstract: Time is what everybody agrees the time is," a researcher says a few pages into Why Time Flies: A Mostly Scientific Investigation. It sounds like something the Mad Hatter might have said in Alice's Adventures in Wonderland. But it's the truth. Time is such a fundamental part of modern life that sometimes we forget how it insinuates itself into everything that we do. In this, his second book, New Yorker staff writer Alan Burdick deftly counts the waysAuthor: Christopher Kemp
      Keywords: Multidisciplinary Studies
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2864
       
  • [Book Review] Travels through time
    • Authors: Christopher Kemp
      Abstract: Time is what everybody agrees the time is," a researcher says a few pages into Why Time Flies: A Mostly Scientific Investigation. It sounds like something the Mad Hatter might have said in Alice's Adventures in Wonderland. But it's the truth. Time is such a fundamental part of modern life that sometimes we forget how it insinuates itself into everything that we do. In this, his second book, New Yorker staff writer Alan Burdick deftly counts the waysAuthor: Christopher Kemp
      Keywords: Multidisciplinary Studies
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2864
       
  • [Book Review] Life in the age of the algorithm
    • Authors: Cathy O'Neil
      Abstract: Andreas Weigend, former chief scientist of Amazon, has written a book— Data for the People: How to Make Our Post-Privacy Economy Work for You—that offers techno-insiders a guide for making the world a more efficient self-branding mechanism. Reviewer Cathy O'Neil dissects Weigend's vision of the future of big data, with an eye toward questions of class, discrimination, and access.Author: Cathy O'Neil
      Keywords: Big Data
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2885
       
  • [Book Review] Life in the age of the algorithm
    • Authors: Cathy O'Neil
      Abstract: Andreas Weigend, former chief scientist of Amazon, has written a book— Data for the People: How to Make Our Post-Privacy Economy Work for You—that offers techno-insiders a guide for making the world a more efficient self-branding mechanism. Reviewer Cathy O'Neil dissects Weigend's vision of the future of big data, with an eye toward questions of class, discrimination, and access.Author: Cathy O'Neil
      Keywords: Big Data
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2885
       
  • [Perspective] Electron diffraction and the hydrogen atom
    • Authors: Lynne B. McCusker
      Abstract: The humble hydrogen atom, with just a single proton and a single electron, is the key to many chemical and biological processes, but precisely because of its low number of electrons, it is difficult to detect even in a single-crystal x-ray diffraction (XRD) experiment. If the material is polycrystalline (crystal volume
      Keywords: Materials Science
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal4570
       
  • [Perspective] Electron diffraction and the hydrogen atom
    • Authors: Lynne B. McCusker
      Abstract: The humble hydrogen atom, with just a single proton and a single electron, is the key to many chemical and biological processes, but precisely because of its low number of electrons, it is difficult to detect even in a single-crystal x-ray diffraction (XRD) experiment. If the material is polycrystalline (crystal volume
      Keywords: Materials Science
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal4570
       
  • [Perspective] Belowground drivers of plant diversity
    • Authors: Wim H. van der Putten
      Abstract: Long before Ernst Haeckel coined the term “ecology” in 1866, nature explorers, such as Alexander von Humboldt, observed that vegetation composition changes with climate. However, it still remains unclear what determines the local composition and species richness of vegetation. Understanding the roles of belowground invertebrates and microbes is particularly challenging. On pages 173 and 181 of this issue, respectively, Teste et al. (1) and Bennett et al. (2) report field studies that elucidate the role of soil microorganisms as drivers of plant community composition.Author: Wim H. van der Putten
      Keywords: Ecology
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal4549
       
  • [Perspective] Belowground drivers of plant diversity
    • Authors: Wim H. van der Putten
      Abstract: Long before Ernst Haeckel coined the term “ecology” in 1866, nature explorers, such as Alexander von Humboldt, observed that vegetation composition changes with climate. However, it still remains unclear what determines the local composition and species richness of vegetation. Understanding the roles of belowground invertebrates and microbes is particularly challenging. On pages 173 and 181 of this issue, respectively, Teste et al. (1) and Bennett et al. (2) report field studies that elucidate the role of soil microorganisms as drivers of plant community composition.Author: Wim H. van der Putten
      Keywords: Ecology
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal4549
       
  • [Perspective] Putting the squeeze on superconductivity
    • Authors: Kyle M. Shen
      Abstract: Superconductivity is a fascinating quantum state of matter that has captured the imagination of physicists for over a century. The pioneering theoretical work of Bardeen, Cooper, and Schrieffer described the superconducting state as a phase-coherent condensate of electrons bound into Cooper pairs, whose distinguishing hallmark, the order parameter, reflects the symmetry of the pair wave function. According to the laws of quantum mechanics, the wave function describing a pair of electrons must possess either even or odd parity. The vast majority of conventional low-temperature superconductors possess order parameters that are approximately isotropic (s-wave), in which the electron spins form a singlet state and hence are of even parity. The small handful of high-temperature superconductors, such as the cuprate and iron-based families, have more complex pairing symmetries (such as d-wave symmetry) but nonetheless are also described by an even-parity state. Odd-parity superconductors are much more elusive and may harbor exotic properties such as Majorana fermions and non-Abelian statistics. On page 148 of this issue, Steppke et al. (1) apply extremely large uniaxial pressures to single crystals of Sr2RuO4, one of the strongest candidates for odd-parity superconductivity, and find a dramatic enhancement of the superconducting transition temperature (Tc) as well as an unexpected change in the superconducting properties under large strains.Author: Kyle M. Shen
      Keywords: Physics
      PubDate: 2017-01-13
      DOI: 10.1126/science.aak9803
       
  • [Perspective] Putting the squeeze on superconductivity
    • Authors: Kyle M. Shen
      Abstract: Superconductivity is a fascinating quantum state of matter that has captured the imagination of physicists for over a century. The pioneering theoretical work of Bardeen, Cooper, and Schrieffer described the superconducting state as a phase-coherent condensate of electrons bound into Cooper pairs, whose distinguishing hallmark, the order parameter, reflects the symmetry of the pair wave function. According to the laws of quantum mechanics, the wave function describing a pair of electrons must possess either even or odd parity. The vast majority of conventional low-temperature superconductors possess order parameters that are approximately isotropic (s-wave), in which the electron spins form a singlet state and hence are of even parity. The small handful of high-temperature superconductors, such as the cuprate and iron-based families, have more complex pairing symmetries (such as d-wave symmetry) but nonetheless are also described by an even-parity state. Odd-parity superconductors are much more elusive and may harbor exotic properties such as Majorana fermions and non-Abelian statistics. On page 148 of this issue, Steppke et al. (1) apply extremely large uniaxial pressures to single crystals of Sr2RuO4, one of the strongest candidates for odd-parity superconductivity, and find a dramatic enhancement of the superconducting transition temperature (Tc) as well as an unexpected change in the superconducting properties under large strains.Author: Kyle M. Shen
      Keywords: Physics
      PubDate: 2017-01-13
      DOI: 10.1126/science.aak9803
       
  • [Perspective] Multiple mechanisms for memory replay?
    • Authors: Richard J. Gardner
      Abstract: Cast your mind back to your childhood. A stream of mental images of events and places appears, like photographs in an album. How do our brains capture and preserve these episodes, and then vividly recall them at will many years later? On page 184 of this issue, O'Neill et al. (1) show that a region of the brain called the medial entorhinal cortex can replay waking experiences. Their work thus challenges the prevailing view that the hippocampus is the sole initiator of spatial and episodic memory reactivation.
      Authors : Richard J. Gardner, May-Britt Moser
      Keywords: Brain Function
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam5404
       
  • [Business Office Feature] Editing the editor: Genome editing gets a
           makeover with CRISPR 2.0
    • Authors: Caitlin Smith
      Abstract: Applications of the genome editing system CRISPR are appearing at a furious pace, and gathering momentum toward therapeutic use in human cells. Indeed, Chinese scientists recently began a human clinical trial using CRISPR-edited cells to fight lung cancer, and U.S. clinical trials are slated to begin in 2017. But leading up to this exciting milestone, researchers performed some editing on the CRISPR system itself. Here's a look at some recent CRISPR upgrades that are helping to move it closer toward use in clinics.Read the Feature (Full-Text HTML)Read the Feature (PDF)Read New Products (PDF)Author: Caitlin Smith
      Keywords: Business Office Feature
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.210-c
       
  • [Working Life] Choosing the hard road
    • Authors: Katharina Henke
      Abstract: Author: Katharina Henke
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.218
       
  • [Working Life] Choosing the hard road
    • Authors: Katharina Henke
      Abstract: Author: Katharina Henke
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.218
       
  • [Business Office Feature] Editing the editor: Genome editing gets a
           makeover with CRISPR 2.0
    • Authors: Caitlin Smith
      Abstract: Applications of the genome editing system CRISPR are appearing at a furious pace, and gathering momentum toward therapeutic use in human cells. Indeed, Chinese scientists recently began a human clinical trial using CRISPR-edited cells to fight lung cancer, and U.S. clinical trials are slated to begin in 2017. But leading up to this exciting milestone, researchers performed some editing on the CRISPR system itself. Here's a look at some recent CRISPR upgrades that are helping to move it closer toward use in clinics.Read the Feature (Full-Text HTML)Read the Feature (PDF)Read New Products (PDF)Author: Caitlin Smith
      Keywords: Business Office Feature
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.210-c
       
  • [Business Office Feature] Webinar Deciphering cancer: Modulating
           immunoregulatory pathways to treat tumors
    • Authors: Jedd D. Wolchok
      Abstract: In addition to being the first line of defense against pathogenic attack, the immune system seeks out aberrant cells within the body that may become cancerous. In response, precancerous and cancerous cells may exploit immune checkpoint pathways to evade immune detection and destruction. In order to block these tumorigenic cells, novel therapeutics that modulate immune checkpoint signaling have been developed, with some already available and others in clinical trials. Further development of effective therapeutics for use in personalized medicine requires the identification and characterization of a diverse range of immune checkpoint biomarkers. This webinar will explore recent progress and future directions in translational and clinical efforts centered on checkpoint modulators and combination therapies matched to the molecular profile of individual tumors and the genetic background of patients.View the Webinar
      Authors : Jedd D. Wolchok, E. John Wherry
      Keywords: Science Webinar Series
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.210-b
       
  • [New Products] New Products
    • Abstract: A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.210-a
       
  • [New Products] New Products
    • Abstract: A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.210-a
       
  • [Business Office Feature] Webinar Deciphering cancer: Modulating
           immunoregulatory pathways to treat tumors
    • Authors: Jedd D. Wolchok
      Abstract: In addition to being the first line of defense against pathogenic attack, the immune system seeks out aberrant cells within the body that may become cancerous. In response, precancerous and cancerous cells may exploit immune checkpoint pathways to evade immune detection and destruction. In order to block these tumorigenic cells, novel therapeutics that modulate immune checkpoint signaling have been developed, with some already available and others in clinical trials. Further development of effective therapeutics for use in personalized medicine requires the identification and characterization of a diverse range of immune checkpoint biomarkers. This webinar will explore recent progress and future directions in translational and clinical efforts centered on checkpoint modulators and combination therapies matched to the molecular profile of individual tumors and the genetic background of patients.View the Webinar
      Authors : Jedd D. Wolchok, E. John Wherry
      Keywords: Science Webinar Series
      PubDate: 2017-01-13
      DOI: 10.1126/science.355.6321.210-b
       
  • [Report] Principles for designing proteins with cavities formed by curved
           β sheets
    • Authors: Enrique Marcos
      Abstract: Active sites and ligand-binding cavities in native proteins are often formed by curved β sheets, and the ability to control β-sheet curvature would allow design of binding proteins with cavities customized to specific ligands. Toward this end, we investigated the mechanisms controlling β-sheet curvature by studying the geometry of β sheets in naturally occurring protein structures and folding simulations. The principles emerging from this analysis were used to design, de novo, a series of proteins with curved β sheets topped with α helices. Nuclear magnetic resonance and crystal structures of the designs closely match the computational models, showing that β-sheet curvature can be controlled with atomic-level accuracy. Our approach enables the design of proteins with cavities and provides a route to custom design ligand-binding and catalytic sites.
      Authors : Enrique Marcos, Benjamin Basanta, Tamuka M. Chidyausiku, Yuefeng Tang, Gustav Oberdorfer, Gaohua Liu, G. V. T. Swapna, Rongjin Guan, Daniel-Adriano Silva, Jiayi Dou, Jose Henrique Pereira, Rong Xiao, Banumathi Sankaran, Peter H. Zwart, Gaetano T. Montelione, David Baker
      PubDate: 2017-01-13
      DOI: 10.1126/science.aah7389
       
  • [Report] Principles for designing proteins with cavities formed by curved
           β sheets
    • Authors: Enrique Marcos
      Abstract: Active sites and ligand-binding cavities in native proteins are often formed by curved β sheets, and the ability to control β-sheet curvature would allow design of binding proteins with cavities customized to specific ligands. Toward this end, we investigated the mechanisms controlling β-sheet curvature by studying the geometry of β sheets in naturally occurring protein structures and folding simulations. The principles emerging from this analysis were used to design, de novo, a series of proteins with curved β sheets topped with α helices. Nuclear magnetic resonance and crystal structures of the designs closely match the computational models, showing that β-sheet curvature can be controlled with atomic-level accuracy. Our approach enables the design of proteins with cavities and provides a route to custom design ligand-binding and catalytic sites.
      Authors : Enrique Marcos, Benjamin Basanta, Tamuka M. Chidyausiku, Yuefeng Tang, Gustav Oberdorfer, Gaohua Liu, G. V. T. Swapna, Rongjin Guan, Daniel-Adriano Silva, Jiayi Dou, Jose Henrique Pereira, Rong Xiao, Banumathi Sankaran, Peter H. Zwart, Gaetano T. Montelione, David Baker
      PubDate: 2017-01-13
      DOI: 10.1126/science.aah7389
       
  • [Report] A bacterial global regulator forms a prion
    • Authors: Andy H. Yuan
      Abstract: Prions are self-propagating protein aggregates that act as protein-based elements of inheritance in fungi. Although prevalent in eukaryotes, prions have not been identified in bacteria. Here we found that a bacterial protein, transcription terminator Rho of Clostridium botulinum (Cb-Rho), could form a prion. We identified a candidate prion-forming domain (cPrD) in Cb-Rho and showed that it conferred amyloidogenicity on Cb-Rho and could functionally replace the PrD of a yeast prion-forming protein. Furthermore, its cPrD enabled Cb-Rho to access alternative conformations in Escherichia coli—a soluble form that terminated transcription efficiently and an aggregated, self-propagating prion form that was functionally compromised. The prion form caused genome-wide changes in the transcriptome. Thus, Cb-Rho functions as a protein-based element of inheritance in bacteria, suggesting that the emergence of prions predates the evolutionary split between eukaryotes and bacteria.
      Authors : Andy H. Yuan, Ann Hochschild
      PubDate: 2017-01-13
      DOI: 10.1126/science.aai7776
       
  • [Report] A bacterial global regulator forms a prion
    • Authors: Andy H. Yuan
      Abstract: Prions are self-propagating protein aggregates that act as protein-based elements of inheritance in fungi. Although prevalent in eukaryotes, prions have not been identified in bacteria. Here we found that a bacterial protein, transcription terminator Rho of Clostridium botulinum (Cb-Rho), could form a prion. We identified a candidate prion-forming domain (cPrD) in Cb-Rho and showed that it conferred amyloidogenicity on Cb-Rho and could functionally replace the PrD of a yeast prion-forming protein. Furthermore, its cPrD enabled Cb-Rho to access alternative conformations in Escherichia coli—a soluble form that terminated transcription efficiently and an aggregated, self-propagating prion form that was functionally compromised. The prion form caused genome-wide changes in the transcriptome. Thus, Cb-Rho functions as a protein-based element of inheritance in bacteria, suggesting that the emergence of prions predates the evolutionary split between eukaryotes and bacteria.
      Authors : Andy H. Yuan, Ann Hochschild
      PubDate: 2017-01-13
      DOI: 10.1126/science.aai7776
       
  • [Report] Assembly of a nucleus-like structure during viral replication in
           bacteria
    • Authors: Vorrapon Chaikeeratisak
      Abstract: We observed the assembly of a nucleus-like structure in bacteria during viral infection. Using fluorescence microscopy and cryo-electron tomography, we showed that Pseudomonas chlororaphis phage 201φ2-1 assembled a compartment that separated viral DNA from the cytoplasm. The phage compartment was centered by a bipolar tubulin-based spindle, and it segregated phage and bacterial proteins according to function. Proteins involved in DNA replication and transcription localized inside the compartment, whereas proteins involved in translation and nucleotide synthesis localized outside. Later during infection, viral capsids assembled on the cytoplasmic membrane and moved to the surface of the compartment for DNA packaging. Ultimately, viral particles were released from the compartment and the cell lysed. These results demonstrate that phages have evolved a specialized structure to compartmentalize viral replication.
      Authors : Vorrapon Chaikeeratisak, Katrina Nguyen, Kanika Khanna, Axel F. Brilot, Marcella L. Erb, Joanna K. C. Coker, Anastasia Vavilina, Gerald L. Newton, Robert Buschauer, Kit Pogliano, Elizabeth Villa, David A. Agard, Joe Pogliano
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2130
       
  • [Report] Assembly of a nucleus-like structure during viral replication in
           bacteria
    • Authors: Vorrapon Chaikeeratisak
      Abstract: We observed the assembly of a nucleus-like structure in bacteria during viral infection. Using fluorescence microscopy and cryo-electron tomography, we showed that Pseudomonas chlororaphis phage 201φ2-1 assembled a compartment that separated viral DNA from the cytoplasm. The phage compartment was centered by a bipolar tubulin-based spindle, and it segregated phage and bacterial proteins according to function. Proteins involved in DNA replication and transcription localized inside the compartment, whereas proteins involved in translation and nucleotide synthesis localized outside. Later during infection, viral capsids assembled on the cytoplasmic membrane and moved to the surface of the compartment for DNA packaging. Ultimately, viral particles were released from the compartment and the cell lysed. These results demonstrate that phages have evolved a specialized structure to compartmentalize viral replication.
      Authors : Vorrapon Chaikeeratisak, Katrina Nguyen, Kanika Khanna, Axel F. Brilot, Marcella L. Erb, Joanna K. C. Coker, Anastasia Vavilina, Gerald L. Newton, Robert Buschauer, Kit Pogliano, Elizabeth Villa, David A. Agard, Joe Pogliano
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2130
       
  • [Report] Causal neural network of metamemory for retrospection in primates
    • Authors: Kentaro Miyamoto
      Abstract: We know how confidently we know: Metacognitive self-monitoring of memory states, so-called “metamemory,” enables strategic and efficient information collection based on past experiences. However, it is unknown how metamemory is implemented in the brain. We explored causal neural mechanism of metamemory in macaque monkeys performing metacognitive confidence judgments on memory. By whole-brain searches via functional magnetic resonance imaging, we discovered a neural correlate of metamemory for temporally remote events in prefrontal area 9 (or 9/46d), along with that for recent events within area 6. Reversible inactivation of each of these identified loci induced doubly dissociated selective impairments in metacognitive judgment performance on remote or recent memory, without impairing recognition performance itself. The findings reveal that parallel metamemory streams supervise recognition networks for remote and recent memory, without contributing to recognition itself.
      Authors : Kentaro Miyamoto, Takahiro Osada, Rieko Setsuie, Masaki Takeda, Keita Tamura, Yusuke Adachi, Yasushi Miyashita
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal0162
       
  • [Report] Causal neural network of metamemory for retrospection in primates
    • Authors: Kentaro Miyamoto
      Abstract: We know how confidently we know: Metacognitive self-monitoring of memory states, so-called “metamemory,” enables strategic and efficient information collection based on past experiences. However, it is unknown how metamemory is implemented in the brain. We explored causal neural mechanism of metamemory in macaque monkeys performing metacognitive confidence judgments on memory. By whole-brain searches via functional magnetic resonance imaging, we discovered a neural correlate of metamemory for temporally remote events in prefrontal area 9 (or 9/46d), along with that for recent events within area 6. Reversible inactivation of each of these identified loci induced doubly dissociated selective impairments in metacognitive judgment performance on remote or recent memory, without impairing recognition performance itself. The findings reveal that parallel metamemory streams supervise recognition networks for remote and recent memory, without contributing to recognition itself.
      Authors : Kentaro Miyamoto, Takahiro Osada, Rieko Setsuie, Masaki Takeda, Keita Tamura, Yusuke Adachi, Yasushi Miyashita
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal0162
       
  • [Report] Superficial layers of the medial entorhinal cortex replay
           independently of the hippocampus
    • Authors: J. O’Neill
      Abstract: The hippocampus is thought to initiate systems-wide mnemonic processes through the reactivation of previously acquired spatial and episodic memory traces, which can recruit the entorhinal cortex as a first stage of memory redistribution to other brain areas. Hippocampal reactivation occurs during sharp wave–ripples, in which synchronous network firing encodes sequences of places. We investigated the coordination of this replay by recording assembly activity simultaneously in the CA1 region of the hippocampus and superficial layers of the medial entorhinal cortex. We found that entorhinal cell assemblies can replay trajectories independently of the hippocampus and sharp wave–ripples. This suggests that the hippocampus is not the sole initiator of spatial and episodic memory trace reactivation. Memory systems involved in these processes may include nonhierarchical, parallel components.
      Authors : J. O’Neill, C.N. Boccara, F. Stella, P. Schoenenberger, J. Csicsvari
      PubDate: 2017-01-13
      DOI: 10.1126/science.aag2787
       
  • [Perspective] A matter of tree longevity
    • Authors: Christian Körner
      Abstract: There is much scientific and political interest in using the transfer of carbon from the atmosphere to the biosphere, or carbon sequestration, to help mitigate the greenhouse effect (1). Because plants fix carbon dioxide (CO2) by photosynthesis and store carbon in their body (close to half of plant dry matter is carbon), faster carbon uptake by plants through faster growth is widely held to increase carbon sequestration. Yet, this assumption is supported by neither theory nor evidence. Any gain in carbon storage from faster tree growth will be transitory.Author: Christian Körner
      Keywords: Carbon Sequestration
      PubDate: 2017-01-13
      DOI: 10.1126/science.aal2449
       
  • [Perspective] Multiple mechanisms for memory replay?
    • Authors: Richard J. Gardner
      Abstract: Cast your mind back to your childhood. A stream of mental images of events and places appears, like photographs in an album. How do our brains capture and preserve these episodes, and then vividly recall them at will many years later? On page 184 of this issue, O'Neill et al. (1) show that a region of the brain called the medial entorhinal cortex can replay waking experiences. Their work thus challenges the prevailing view that the hippocampus is the sole initiator of spatial and episodic memory reactivation.
      Authors : Richard J. Gardner, May-Britt Moser
      Keywords: Brain Function
      PubDate: 2017-01-13
      DOI: 10.1126/science.aam5404
       
 
 
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