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[Editors' Choice] Threading the needle with manganese

Thu, 10/29/2015 - 23:00
Author: Jake Yeston
Categories: Journal Articles

[Editors' Choice] Skin cell–derived neurons act their age

Thu, 10/29/2015 - 23:00
Author: Stella M. Hurtley
Categories: Journal Articles

[Editors' Choice] Tweaking atomic interactions optically

Thu, 10/29/2015 - 23:00
Author: Jelena Stajic
Categories: Journal Articles

[Editors' Choice] A suite in flux

Thu, 10/29/2015 - 23:00
Author: H. Jesse Smith
Categories: Journal Articles

[Editors' Choice] Yeast reveal the secrets for a long life

Thu, 10/29/2015 - 23:00
Author: Barbara R. Jasny
Categories: Journal Articles

[Editors' Choice] Trusting robots but not androids

Thu, 10/29/2015 - 23:00
Author: Gilbert Chin
Categories: Journal Articles

[Review] The realities of risk-cost-benefit analysis

Thu, 10/29/2015 - 23:00
Formal analyses can be valuable aids to decision-making if their limits are understood. Those limits arise from the two forms of subjectivity found in all analyses: ethical judgments, made when setting the terms of an analysis, and scientific judgments, made when conducting it. As formal analysis has assumed a larger role in policy decisions, awareness of those judgments has grown, as have methods for making them. The present review traces these developments, using examples that illustrate the issues that arise when designing, executing, and interpreting analyses. It concludes with lessons learned from the science and practice of analysis. One common thread in these lessons is the importance of collaborative processes, whereby analysts and decision-makers educate one another about their respective needs and capabilities. Author: Baruch Fischhoff
Categories: Journal Articles

[Research Article] Miocene small-bodied ape from Eurasia sheds light on hominoid evolution

Thu, 10/29/2015 - 23:00
Miocene small-bodied anthropoid primates from Africa and Eurasia are generally considered to precede the divergence between the two groups of extant catarrhines—hominoids (apes and humans) and Old World monkeys—and are thus viewed as more primitive than the stem ape Proconsul. Here we describe Pliobates cataloniae gen. et sp. nov., a small-bodied (4 to 5 kilograms) primate from the Iberian Miocene (11.6 million years ago) that displays a mosaic of primitive characteristics coupled with multiple cranial and postcranial shared derived features of extant hominoids. Our cladistic analyses show that Pliobates is a stem hominoid that is more derived than previously described small catarrhines and Proconsul. This forces us to reevaluate the role played by small-bodied catarrhines in ape evolution and provides key insight into the last common ancestor of hylobatids (gibbons) and hominids (great apes and humans). Authors: David M. Alba, Sergio Almécija, Daniel DeMiguel, Josep Fortuny, Miriam Pérez de los Ríos, Marta Pina, Josep M. Robles, Salvador Moyà-Solà
Categories: Journal Articles

[Research Article] Structure of Tetrahymena telomerase reveals previously unknown subunits, functions, and interactions

Thu, 10/29/2015 - 23:00
Telomerase helps maintain telomeres by processive synthesis of telomere repeat DNA at their 3′-ends, using an integral telomerase RNA (TER) and telomerase reverse transcriptase (TERT). We report the cryo–electron microscopy structure of Tetrahymena telomerase at ~9 angstrom resolution. In addition to seven known holoenzyme proteins, we identify two additional proteins that form a complex (TEB) with single-stranded telomere DNA-binding protein Teb1, paralogous to heterotrimeric replication protein A (RPA). The p75-p45-p19 subcomplex is identified as another RPA-related complex, CST (CTC1-STN1-TEN1). This study reveals the paths of TER in the TERT-TER-p65 catalytic core and single-stranded DNA exit; extensive subunit interactions of the TERT essential N-terminal domain, p50, and TEB; and other subunit identities and structures, including p19 and p45C crystal structures. Our findings provide structural and mechanistic insights into telomerase holoenzyme function. Authors: Jiansen Jiang, Henry Chan, Darian D. Cash, Edward J. Miracco, Rachel R. Ogorzalek Loo, Heather E. Upton, Duilio Cascio, Reid O’Brien Johnson, Kathleen Collins, Joseph A. Loo, Z. Hong Zhou, Juli Feigon
Categories: Journal Articles

[Research Article] Cycling Li-O2 batteries via LiOH formation and decomposition

Thu, 10/29/2015 - 23:00
The rechargeable aprotic lithium-air (Li-O2) battery is a promising potential technology for next-generation energy storage, but its practical realization still faces many challenges. In contrast to the standard Li-O2 cells, which cycle via the formation of Li2O2, we used a reduced graphene oxide electrode, the additive LiI, and the solvent dimethoxyethane to reversibly form and remove crystalline LiOH with particle sizes larger than 15 micrometers during discharge and charge. This leads to high specific capacities, excellent energy efficiency (93.2%) with a voltage gap of only 0.2 volt, and impressive rechargeability. The cells tolerate high concentrations of water, water being the dominant proton source for the LiOH; together with LiI, it has a decisive impact on the chemical nature of the discharge product and on battery performance. Authors: Tao Liu, Michal Leskes, Wanjing Yu, Amy J. Moore, Lina Zhou, Paul M. Bayley, Gunwoo Kim, Clare P. Grey
Categories: Journal Articles

[Report] Geophysical imaging reveals topographic stress control of bedrock weathering

Thu, 10/29/2015 - 23:00
Bedrock fracture systems facilitate weathering, allowing fresh mineral surfaces to interact with corrosive waters and biota from Earth’s surface, while simultaneously promoting drainage of chemically equilibrated fluids. We show that topographic perturbations to regional stress fields explain bedrock fracture distributions, as revealed by seismic velocity and electrical resistivity surveys from three landscapes. The base of the fracture-rich zone mirrors surface topography where the ratio of horizontal compressive tectonic stresses to near-surface gravitational stresses is relatively large, and it parallels the surface topography where the ratio is relatively small. Three-dimensional stress calculations predict these results, suggesting that tectonic stresses interact with topography to influence bedrock disaggregation, groundwater flow, chemical weathering, and the depth of the “critical zone” in which many biogeochemical processes occur. Authors: J. St. Clair, S. Moon, W. S. Holbrook, J. T. Perron, C. S. Riebe, S. J. Martel, B. Carr, C. Harman, K. Singha, D. deB. Richter
Categories: Journal Articles

[Report] Mobile metallic domain walls in an all-in-all-out magnetic insulator

Thu, 10/29/2015 - 23:00
Magnetic domain walls are boundaries between regions with different configurations of the same magnetic order. In a magnetic insulator, where the magnetic order is tied to its bulk insulating property, it has been postulated that electrical properties are drastically different along the domain walls, where the order is inevitably disturbed. Here we report the discovery of highly conductive magnetic domain walls in a magnetic insulator, Nd2Ir2O7, that has an unusual all-in-all-out magnetic order, via transport and spatially resolved microwave impedance microscopy. The domain walls have a virtually temperature-independent sheet resistance of ~1 kilohm per square, show smooth morphology with no preferred orientation, are free from pinning by disorders, and have strong thermal and magnetic field responses that agree with expectations for all-in-all-out magnetic order. Authors: Eric Yue Ma, Yong-Tao Cui, Kentaro Ueda, Shujie Tang, Kai Chen, Nobumichi Tamura, Phillip M. Wu, Jun Fujioka, Yoshinori Tokura, Zhi-Xun Shen
Categories: Journal Articles

[Report] Quantum Griffiths singularity of superconductor-metal transition in Ga thin films

Thu, 10/29/2015 - 23:00
The Griffiths singularity in a phase transition, caused by disorder effects, was predicted more than 40 years ago. Its signature, the divergence of the dynamical critical exponent, is challenging to observe experimentally. We report the experimental observation of the quantum Griffiths singularity in a two-dimensional superconducting system. We measured the transport properties of atomically thin gallium films and found that the films undergo superconductor-metal transitions with increasing magnetic field. Approaching the zero-temperature quantum critical point, we observed divergence of the dynamical critical exponent, which is consistent with the Griffiths singularity behavior. We interpret the observed superconductor-metal quantum phase transition as the infinite-randomness critical point, where the properties of the system are controlled by rare large superconducting regions. Authors: Ying Xing, Hui-Min Zhang, Hai-Long Fu, Haiwen Liu, Yi Sun, Jun-Ping Peng, Fa Wang, Xi Lin, Xu-Cun Ma, Qi-Kun Xue, Jian Wang, X. C. Xie
Categories: Journal Articles

[Report] Peer effects on worker output in the laboratory generalize to the field

Thu, 10/29/2015 - 23:00
We compare estimates of peer effects on worker output in laboratory experiments and field studies from naturally occurring environments. The mean study-level estimate of a change in a worker’s productivity in response to an increase in a co-worker’s productivity (γ) is γ^ = 0.12 (SE = 0.03, nstudies = 34), with a between-study standard deviation τ = 0.16. The mean estimated γ^-values are close between laboratory and field studies (γ^lab−γ^field = 0.04, P = 0.55, nlab = 11, nfield = 23), as are estimates of between-study variance τ2 (τ^lab2−τ^field2=−0.003, P = 0.89). The small mean difference between laboratory and field estimates holds even after controlling for sample characteristics such as incentive schemes and work complexity (γ^lab−γ^field = 0.03, P = 0.62, nsamples = 46). Laboratory experiments generalize quantitatively in that they provide an accurate description of the mean and variance of productivity spillovers. Authors: Daniel Herbst, Alexandre Mas
Categories: Journal Articles

[Report] Gate control of mechanical itch by a subpopulation of spinal cord interneurons

Thu, 10/29/2015 - 23:00
Light mechanical stimulation of hairy skin can induce a form of itch known as mechanical itch. This itch sensation is normally suppressed by inputs from mechanoreceptors; however, in many forms of chronic itch, including alloknesis, this gating mechanism is lost. Here we demonstrate that a population of spinal inhibitory interneurons that are defined by the expression of neuropeptide Y::Cre (NPY::Cre) act to gate mechanical itch. Mice in which dorsal NPY::Cre-derived neurons are selectively ablated or silenced develop mechanical itch without an increase in sensitivity to chemical itch or pain. This chronic itch state is histamine-independent and is transmitted independently of neurons that express the gastrin-releasing peptide receptor. Thus, our studies reveal a dedicated spinal cord inhibitory pathway that gates the transmission of mechanical itch. Authors: Steeve Bourane, Bo Duan, Stephanie C. Koch, Antoine Dalet, Olivier Britz, Lidia Garcia-Campmany, Euiseok Kim, Longzhen Cheng, Anirvan Ghosh, Qiufu Ma, Martyn Goulding
Categories: Journal Articles

[Report] A GABAergic projection from the zona incerta to cortex promotes cortical neuron development

Thu, 10/29/2015 - 23:00
γ-Aminobutyric acid (GABA) is the major inhibitory transmitter in the mature brain but is excitatory in the developing cortex. We found that mouse zona incerta (ZI) projection neurons form a GABAergic axon plexus in neonatal cortical layer 1, making synapses with neurons in both deep and superficial layers. A similar depolarizing GABAergic plexus exists in the developing human cortex. Selectively silencing mouse ZI GABAergic neurons at birth decreased synaptic activity and apical dendritic complexity of cortical neurons. The ZI GABAergic projection becomes inhibitory with maturation and can block epileptiform activity in the adult brain. These data reveal an early-developing GABAergic projection from the ZI to cortical layer 1 that is essential for proper development of cortical neurons and balances excitation with inhibition in the adult cortex. Authors: Jiadong Chen, Arnold R. Kriegstein
Categories: Journal Articles

[Report] Disease tolerance mediated by microbiome E. coli involves inflammasome and IGF-1 signaling

Thu, 10/29/2015 - 23:00
Infections and inflammation can lead to cachexia and wasting of skeletal muscle and fat tissue by as yet poorly understood mechanisms. We observed that gut colonization of mice by a strain of Escherichia coli prevents wasting triggered by infections or physical damage to the intestine. During intestinal infection with the pathogen Salmonella Typhimurium or pneumonic infection with Burkholderia thailandensis, the presence of this E. coli did not alter changes in host metabolism, caloric uptake, or inflammation but instead sustained signaling of the insulin-like growth factor 1/phosphatidylinositol 3-kinase/AKT pathway in skeletal muscle, which is required for prevention of muscle wasting. This effect was dependent on engagement of the NLRC4 inflammasome. Therefore, this commensal promotes tolerance to diverse diseases. Authors: Alexandria M. Palaferri Schieber, Yujung Michelle Lee, Max W. Chang, Mathias Leblanc, Brett Collins, Michael Downes, Ronald M. Evans, Janelle S. Ayres
Categories: Journal Articles

[Report] Retroviruses use CD169-mediated trans-infection of permissive lymphocytes to establish infection

Thu, 10/29/2015 - 23:00
Dendritic cells can capture and transfer retroviruses in vitro across synaptic cell-cell contacts to uninfected cells, a process called trans-infection. Whether trans-infection contributes to retroviral spread in vivo remains unknown. Here, we visualize how retroviruses disseminate in secondary lymphoid tissues of living mice. We demonstrate that murine leukemia virus (MLV) and human immunodeficiency virus (HIV) are first captured by sinus-lining macrophages. CD169/Siglec-1, an I-type lectin that recognizes gangliosides, captures the virus. MLV-laden macrophages then form long-lived synaptic contacts to trans-infect B-1 cells. Infected B-1 cells subsequently migrate into the lymph node to spread the infection through virological synapses. Robust infection in lymph nodes and spleen requires CD169, suggesting that a combination of fluid-based movement followed by CD169-dependent trans-infection can contribute to viral spread. Authors: Xaver Sewald, Mark S. Ladinsky, Pradeep D. Uchil, Jagadish Beloor, Ruoxi Pi, Christin Herrmann, Nasim Motamedi, Thomas T. Murooka, Michael A. Brehm, Dale L. Greiner, Leonard D. Shultz, Thorsten R. Mempel, Pamela J. Bjorkman, Priti Kumar, Walther Mothes
Categories: Journal Articles

[Report] DNA tumor virus oncogenes antagonize the cGAS-STING DNA-sensing pathway

Thu, 10/29/2015 - 23:00
Cyclic guanosine monophosphate–adenosine monophosphate synthase (cGAS) detects intracellular DNA and signals through the adapter protein STING to initiate the antiviral response to DNA viruses. Whether DNA viruses can prevent activation of the cGAS-STING pathway remains largely unknown. Here, we identify the oncogenes of the DNA tumor viruses, including E7 from human papillomavirus (HPV) and E1A from adenovirus, as potent and specific inhibitors of the cGAS-STING pathway. We show that the LXCXE motif of these oncoproteins, which is essential for blockade of the retinoblastoma tumor suppressor, is also important for antagonizing DNA sensing. E1A and E7 bind to STING, and silencing of these oncogenes in human tumor cells restores the cGAS-STING pathway. Our findings reveal a host-virus conflict that may have shaped the evolution of viral oncogenes. Authors: Laura Lau, Elizabeth E. Gray, Rebecca L. Brunette, Daniel B. Stetson
Categories: Journal Articles

[New Products] New Products

Thu, 10/29/2015 - 23:00
A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.
Categories: Journal Articles