Science news

• [Working Life] The transcontinental scientist

  19-01-2017 23:52
  Author: Wim Delva
  
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• [This Week in Science] Working as a pair

  19-01-2017 23:52
  Author: Valda Vinson
  
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• [This Week in Science] Using technology to beat corruption

  19-01-2017 23:52
  Author: Julia Fahrenkamp-Uppenbrink
  
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• [This Week in Science] Small peptides allow rapid responses

  19-01-2017 23:52
  Author: Pamela J. Hines
  
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• [This Week in Science] Sea surface temperatures of the past

  19-01-2017 23:52
  Author: H. Jesse Smith
  
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• [This Week in Science] Robots have a change of heart

  19-01-2017 23:52
  Author: Caitlin Czajka
  
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• [This Week in Science] Moving transistors downscale

  19-01-2017 23:52
  Author: Phil Szuromi
  
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• [This Week in Science] Locking TNFR2 to kill ovarian cancer

  19-01-2017 23:52
  Author: Leslie K. Ferrarelli
  
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• [This Week in Science] Keeping roots water-tight

  19-01-2017 23:52
  Author: Pamela J. Hines
  
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• [This Week in Science] Impending primate extinction

  19-01-2017 23:52
  Author: Michael Hochberg
  
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• [This Week in Science] Filling in the protein fold picture

  19-01-2017 23:52
  Author: Valda Vinson
  
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• [This Week in Science] Ethics of organoid research

  19-01-2017 23:52
  Author: Beverly A. Purnell
  
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• [This Week in Science] Deformation powers the nucleosome slide

  19-01-2017 23:52
  Author: Guy Riddihough
  
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• [This Week in Science] Deciding a protein's fate

  19-01-2017 23:52
  Author: Valda Vinson
  
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• [This Week in Science] Chromosomal chaos and tumor immunity

  19-01-2017 23:52
  Author: Paula A. Kiberstis
  
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• [This Week in Science] An x-ray view of C–F and S–F bond breaks

  19-01-2017 23:52
  Author: Jake Yeston
  
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• [This Week in Science] Alcohols remove lithium to make nanowires

  19-01-2017 23:52
  Author: Marc S. Lavine
  
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• [Review] Human tissues in a dish: The research and ethical implications of organoid technology

  19-01-2017 23:52
  The ability to generate human tissues in vitro from stem cells has raised enormous expectations among the biomedical research community, patients, and the general public. These organoids enable studies of normal development and disease and allow the testing of compounds directly on human tissue. Organoids hold the promise to influence the entire innovation cycle in biomedical research. They affect fields that have been subjects of intense ethical debate, ranging from animal experiments and the u
  
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• [Research Article] Tumor aneuploidy correlates with markers of immune evasion and with reduced response to immunotherapy

  19-01-2017 23:52
  Immunotherapies based on immune checkpoint blockade are highly effective in a subset of patients. An ongoing challenge is the identification of biomarkers that predict which patients will benefit from these therapies. Aneuploidy, also known as somatic copy number alterations (SCNAs), is widespread in cancer and is posited to drive tumorigenesis. Analyzing 12 human cancer types, we find that, for most, highly aneuploid tumors show reduced expression of markers of cytotoxic infiltrating immune cel
  
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• [Research Article] The role of dimer asymmetry and protomer dynamics in enzyme catalysis

  19-01-2017 23:52
  Freeze-trapping x-ray crystallography, nuclear magnetic resonance, and computational techniques reveal the distribution of states and their interconversion rates along the reaction pathway of a bacterial homodimeric enzyme, fluoroacetate dehalogenase (FAcD). The crystal structure of apo-FAcD exhibits asymmetry around the dimer interface and cap domain, priming one protomer for substrate binding. This asymmetry is dynamically averaged through conformational exchange on a millisecond time scale. D
  
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• [Research Article] Distortion of histone octamer core promotes nucleosome mobilization by a chromatin remodeler

  19-01-2017 23:52
  Adenosine 5′-triphosphate (ATP)–dependent chromatin remodeling enzymes play essential biological roles by mobilizing nucleosomal DNA. Yet, how DNA is mobilized despite the steric constraints placed by the histone octamer remains unknown. Using methyl transverse relaxation–optimized nuclear magnetic resonance spectroscopy on a 450-kilodalton complex, we show that the chromatin remodeler, SNF2h, distorts the histone octamer. Binding of SNF2h in an activated ATP state changes the dynamics of
  
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• [Report] Transformation of bulk alloys to oxide nanowires

  19-01-2017 23:52
  One dimensional (1D) nanostructures offer prospects for enhancing the electrical, thermal, and mechanical properties of a broad range of functional materials and composites, but their synthesis methods are typically elaborate and expensive. We demonstrate a direct transformation of bulk materials into nanowires under ambient conditions without the use of catalysts or any external stimuli. The nanowires form via minimization of strain energy at the boundary of a chemical reaction front. We show t
  
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• [Report] Time-resolved x-ray absorption spectroscopy with a water window high-harmonic source

  19-01-2017 23:52
  Time-resolved x-ray absorption spectroscopy (TR-XAS) has so far practically been limited to large-scale facilities, to subpicosecond temporal resolution, and to the condensed phase. We report the realization of TR-XAS with a temporal resolution in the low femtosecond range by developing a tabletop high-harmonic source reaching up to 350 electron volts, thus partially covering the spectral region of 280 to 530 electron volts, where water is transmissive. We used this source to follow previously u
  
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• [Report] The receptor kinase FER is a RALF-regulated scaffold controlling plant immune signaling

  19-01-2017 23:52
  In plants, perception of invading pathogens involves cell-surface immune receptor kinases. Here, we report that the Arabidopsis SITE-1 PROTEASE (S1P) cleaves endogenous RAPID ALKALINIZATION FACTOR (RALF) propeptides to inhibit plant immunity. This inhibition is mediated by the malectin-like receptor kinase FERONIA (FER), which otherwise facilitates the ligand-induced complex formation of the immune receptor kinases EF-TU RECEPTOR (EFR) and FLAGELLIN-SENSING 2 (FLS2) with their co-receptor BRASSI
  
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• [Report] Scaling carbon nanotube complementary transistors to 5-nm gate lengths

  19-01-2017 23:52
  High-performance top-gated carbon nanotube field-effect transistors (CNT FETs) with a gate length of 5 nanometers can be fabricated that perform better than silicon complementary metal-oxide semiconductor (CMOS) FETs at the same scale. A scaling trend study revealed that the scaled CNT-based devices, which use graphene contacts, can operate much faster and at much lower supply voltage (0.4 versus 0.7 volts) and with much smaller subthreshold slope (typically 73 millivolts per decade). The 5-nano
  
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• [Report] Root diffusion barrier control by a vasculature-derived peptide binding to the SGN3 receptor

  19-01-2017 23:52
  The root endodermis forms its extracellular diffusion barrier by developing ringlike impregnations called Casparian strips. A factor responsible for their establishment is the SCHENGEN3/GASSHO1 (SGN3/GSO1) receptor-like kinase. Its loss of function causes discontinuous Casparian strips. SGN3 also mediates endodermal overlignification of other Casparian strip mutants. Yet, without ligand, SGN3 function remained elusive. Here we report that schengen2 (sgn2) is defective in an enzyme sulfating pept
  
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• [Report] Regional and global sea-surface temperatures during the last interglaciation

  19-01-2017 23:52
  The last interglaciation (LIG, 129 to 116 thousand years ago) was the most recent time in Earth’s history when global mean sea level was substantially higher than it is at present. However, reconstructions of LIG global temperature remain uncertain, with estimates ranging from no significant difference to nearly 2°C warmer than present-day temperatures. Here we use a network of sea-surface temperature (SST) records to reconstruct spatiotemporal variability in regional and global SSTs during t
  
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• [Report] Protein structure determination using metagenome sequence data

  19-01-2017 23:52
  Despite decades of work by structural biologists, there are still ~5200 protein families with unknown structure outside the range of comparative modeling. We show that Rosetta structure prediction guided by residue-residue contacts inferred from evolutionary information can accurately model proteins that belong to large families and that metagenome sequence data more than triple the number of protein families with sufficient sequences for accurate modeling. We then integrate metagenome data, con
  
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• [Report] Mechanistic basis for a molecular triage reaction

  19-01-2017 23:52
  Newly synthesized proteins are triaged between biosynthesis and degradation to maintain cellular homeostasis, but the decision-making mechanisms are unclear. We reconstituted the core reactions for membrane targeting and ubiquitination of nascent tail-anchored membrane proteins to understand how their fate is determined. The central six-component triage system is divided into an uncommitted client-SGTA complex, a self-sufficient targeting module, and an embedded but self-sufficient quality contr
  
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• [Report] Evolutionary drivers of thermoadaptation in enzyme catalysis

  19-01-2017 23:52
  With early life likely to have existed in a hot environment, enzymes had to cope with an inherent drop in catalytic speed caused by lowered temperature. Here we characterize the molecular mechanisms underlying thermoadaptation of enzyme catalysis in adenylate kinase using ancestral sequence reconstruction spanning 3 billion years of evolution. We show that evolution solved the enzyme’s key kinetic obstacle—how to maintain catalytic speed on a cooler Earth—by exploiting transition-state hea
  
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• [Report] A peptide hormone required for Casparian strip diffusion barrier formation in Arabidopsis roots

  19-01-2017 23:52
  Plants achieve mineral ion homeostasis by means of a hydrophobic barrier on endodermal cells called the Casparian strip, which restricts lateral diffusion of ions between the root vascular bundles and the soil. We identified a family of sulfated peptides required for contiguous Casparian strip formation in Arabidopsis roots. These peptide hormones, which we named Casparian strip integrity factor 1 (CIF1) and CIF2, are expressed in the root stele and specifically bind the endodermis-expressed leu
  
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• [Policy Forum] Closing global achievement gaps in MOOCs

  19-01-2017 23:52
  Advocates for free massive open online courses (MOOCs) have heralded them as vehicles for democratizing education and bridging divides within and across countries (1). More than 25 million people enrolled in MOOCs between 2012 and 2015, including 39% from less-developed countries (LDCs) (2). But the educated and affluent in all countries enroll in and complete MOOCs at relatively higher rates (3, 4). Judged by completion rates, MOOCs do not spread benefits equitably across global regions. Rather
  
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• [Perspective] Unlocking the nucleosome

  19-01-2017 23:52
  Almost all eukaryotic genomes are packaged as nucleosomal building blocks that are assembled from an octameric core of histone proteins around which nearly two turns of DNA are wrapped. The apparent homogeneity and stability of nucleosomes has led to their depiction as beads, balls, and other simplifications that imply a largely static histone structural surface on which DNA wraps and unwraps. On page 263 of this issue, Sinha et al. (1) enrich our understanding of nucleosome behavior with direct
  
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• [Perspective] Technology beats corruption

  19-01-2017 23:52
  More than 1.9 billion individuals in the developing world benefit from social safety net programs: noncontributory transfer programs that distribute cash or basic in-kind products to the poor. But despite their importance, high levels of corruption often stifle the effectiveness of these programs. If cash transfer programs are particularly prone to graft, then in-kind programs should be preferred in practice. In a recent paper, Muralidharan et al. report evidence to the contrary by showing that
  
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• [Perspective] Enzymes at work are enzymes in motion

  19-01-2017 23:52
  Enzymes provide the necessary impetus for chemical reactions to occur at a rate that can support biological life. They do so by forming a unique enzyme-substrate complex and thus lowering the energy required for a substrate to convert to a product. Numerous approaches have been used for more than 50 years to unravel the mechanisms of enzyme-mediated catalysis (1). Initial kinetic experiments helped to ascertain substrate specificity. Spectroscopic data have shown that enzymes are not static, and
  
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• [Perspective] Chromosomal chaos silences immune surveillance

  19-01-2017 23:52
  Not all cancers, and not all individuals with the same cancer type, respond equally to immunotherapy—the use of antibodies to block so-called immune checkpoints in T cells—thereby unleashing immune responses against tumor cells. This can be partially explained by nonsynonymous mutations, which can create neoantigen epitopes that induce T cell responses against cancer cells (1). However, such mutations scattered throughout the genome may or may not activate the immune system, and if they do,
  
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• [Perspective] Big-data approaches to protein structure prediction

  19-01-2017 23:52
  A protein's structure determines its function. Experimental protein structure determination is cumbersome and costly, which has driven the search for methods that can predict protein structure from sequence information (1). About half of the known proteins are amenable to comparative modeling; that is, an evolutionarily related protein of known structure can be used as a template for modeling the unknown structure. For the remaining proteins, no satisfactory solution had been found. On page 294
  
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• [Letter] Wildlife-snaring crisis in Asian forests

  19-01-2017 23:52
  Authors: Thomas N. E. Gray, Antony J. Lynam, Teak Seng, William F. Laurance, Barney Long, Lorraine Scotson, William J. Ripple
  
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• [Letter Letters letters Outside the Tower] Young science officers lead by example

  19-01-2017 23:52
  Author: Dhruv Iyer
  
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• [Letter] Building community for deaf scientists

  19-01-2017 23:52
  Authors: Gerry Buckley, Scott Smith, James DeCaro, Steve Barnett, Steve Dewhurst
  
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• [In Depth] Your self-driving car could kill radio astronomy

  19-01-2017 23:52
  Add energy-saving streetlights, self-driving cars, and balloon-borne internet services to the threats facing astronomers needing dark skies free of electromagnetic smog. The rise of all three technologies is posing new challenges to ground-based researchers who use the optical and radio spectrum to observe the universe, speakers warned earlier this month at the annual meeting of the American Astronomical Societ in Grapevine, Texas. The main problem with light-emitting diodes (LEDs) is not that t
  
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• [In Depth] Unique free electron laser laboratory opens in China

  19-01-2017 23:52
  China has become the latest country making a free electron laser available to its scientists. Researchers around the world want access to these lasers because they are an advance on the synchrotron light sources that have been the workhorses of protein crystallography, cell biology, and materials science. The completion of the $30 million Dalian Coherent Light Source, announced this week in Beijing, has a twist that makes it unique: It is the only large laser light source in the world dedicated
  
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• [In Depth] Science suffers in cold war over polar base

  19-01-2017 23:52
  It's summer in Antarctica, the season for science. But at the Princess Elisabeth Antarctica research station, Belgium's futuristic research outpost in East Antarctica, not a single Belgian researcher is at work. A protracted dispute between the Belgian government and the International Polar Foundation, which built and operates the station, has resulted in the cancellation of this year's Belgian expedition to Antarctica. The only scientists to pay a visit so far this year are two scientists from
  
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• [In Depth] Mixed results from cancer replications unsettle field

  19-01-2017 23:52
  The first results of a high-profile effort to replicate dozens of influential papers in cancer biology are roiling the biomedical community. Of the five studies the project has tackled so far, some involving experimental treatments already in clinical trials, only two could be repeated; one could not, and technical problems stymied the remaining two replication efforts. Some scientists say these early findings from the Reproducibility Project: Cancer Biology, which appear this week in eLife, bol
  
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• [In Depth] How do gut microbes help herbivores? Counting the ways

  19-01-2017 23:52
  No matter what a vegan may tell you, a solely plant-based diet is a tough way to get all the calories and nutrients you need. Unless you have the right microbial partners. At the recent annual meeting of the Society for Integrative and Comparative Biology, researchers made it clear that microbes lend a wide array of other talents to herbivores. One gut microbe helps a tropical ant recycle nitrogen, which is scarce in plant matter and is vital for making proteins. Another aids leaf beetles by bre
  
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• [In Depth] A half-billion-dollar bid to head off emerging diseases

  19-01-2017 23:52
  In the wake of the Ebola crisis that erupted in West Africa in 2014, many public health leaders recognized that a more aggressive effort to develop vaccines could have moved a vaccine forward more quickly and prevented that outbreak from becoming an epidemic. A new organization was formed last year, the Coalition for Epidemic Preparedness Innovations (CEPI), to speed development of vaccines against emerging infectious diseases—but it had no serious financial backing. Now, CEPI has att
  
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• [Feature] Taming rabies

  19-01-2017 23:52
  An estimated 59,000 people die from rabies around the world every year. Their horrible suffering—including convulsions, terror, and aggression—and the fact that many victims are children led the World Health Organization and others to announce a goal to eliminate rabies deaths worldwide by 2030. The plan calls for cheaper and faster treatment for people. But its long-term bet is on vaccinating domestic dogs, which cause more than 99% of infections. The challenges are enormous in sub-Saharan
  
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• [Editors' Choice] Making garnets the hard way

  19-01-2017 23:52
  Author: Brent Grocholski
  
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• [Editors' Choice] Know who you are asking for money

  19-01-2017 23:52
  Author: Gilbert Chin
  
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• [Editors' Choice] DNA methylation in hematopoietic cascade

  19-01-2017 23:52
  Author: Beverly A. Purnell
  
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