Science news

• [Working Life] How I'm standing up for science

  23-02-2017 23:57
  Author: Susan J. Cheng
  
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• [This Week in Science] What's in a fold?

  23-02-2017 23:57
  Author: Stella M. Hurtley
  
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• [This Week in Science] Very clever bees use tools

  23-02-2017 23:57
  Author: Sacha Vignieri
  
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• [This Week in Science] Spinning up an extragalactic neutron star

  23-02-2017 23:57
  Author: Keith T. Smith
  
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• [This Week in Science] Shining a light on cell signaling

  23-02-2017 23:57
  Author: Valda Vinson
  
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• [This Week in Science] Resistance on a background of tolerance

  23-02-2017 23:57
  Author: Caroline Ash
  
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• [This Week in Science] How will this molecule smell?

  23-02-2017 23:57
  Author: Peter Stern
  
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• [This Week in Science] How to make opposites compatible

  23-02-2017 23:57
  Author: Marc S. Lavine
  
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• [This Week in Science] How red berries reduce inflammation

  23-02-2017 23:57
  Author: John F. Foley
  
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• [This Week in Science] How dinosaurs took to the air

  23-02-2017 23:57
  Author: Julia Fahrenkamp-Uppenbrink
  
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• [This Week in Science] Faulty blood cells and heart disease

  23-02-2017 23:57
  Author: Paula A. Kiberstis
  
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• [This Week in Science] DNA charged with regulating replication

  23-02-2017 23:57
  Authors: Guy Riddihough, Jake Yeston
  
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• [This Week in Science] Diverse molecular choreography of replication

  23-02-2017 23:57
  Authors: Guy Riddihough, Caroline Ash
  
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• [This Week in Science] Defining the tree rings of T cells

  23-02-2017 23:57
  Author: Anand Balasubramani
  
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• [This Week in Science] Bacterial battles on your skin

  23-02-2017 23:57
  Author: Lindsey Pujanandez
  
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• [Technical Response] Response to Comments on “Ducklings imprint on the relational concept of ‘same or different’”

  23-02-2017 23:57
  Two Comments by Hupé and by Langbein and Puppe address our choice of statistical analysis in assigning preference between sets of stimuli to individual ducklings in our paper. We believe that our analysis remains the most appropriate approach for our data and experimental design.
  Authors: Antone Martinho, Alex Kacelnik
  
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• [Technical Comment] Comment on “Ducklings imprint on the relational concept of ‘same or different'”

  23-02-2017 23:57
  Martinho and Kacelnik’s (Reports, 15 July 2016, p. 286) finding that mallard ducklings can deal with abstract concepts is important for understanding the evolution of cognition. However, a statistically more robust analysis of the data calls their conclusions into question. This example brings to light the risk of drawing too strong an inference by relying solely on P values.
  Author: Jean-Michel Hupé
  
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• [Technical Comment] Comment on “Ducklings imprint on the relational concept of ‘same or different’”

  23-02-2017 23:57
  Martinho and Kacelnik (Reports, 15 July 2016, p. 286) reported that newly hatched ducklings imprinted on relational concepts. We argue that reanalyzing the data at the individual level shows that this conclusion cannot be applied for all sets of stimuli presented and that the ability to grasp relational concepts is limited to the stimulus category that is most beneficial for survival.
  Authors: Jan Langbein, Birger Puppe
  
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• [Review] Mechanisms for initiating cellular DNA replication

  23-02-2017 23:57
  Cellular DNA replication factories depend on ring-shaped hexameric helicases to aid DNA synthesis by processively unzipping the parental DNA helix. Replicative helicases are loaded onto DNA by dedicated initiator, loader, and accessory proteins during the initiation of DNA replication in a tightly regulated, multistep process. We discuss here the molecular choreography of DNA replication initiation across the three domains of life, highlighting similarities and differences in the strategies used
  
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• [Research Article] The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport

  23-02-2017 23:57
  DNA charge transport chemistry offers a means of long-range, rapid redox signaling. We demonstrate that the [4Fe4S] cluster in human DNA primase can make use of this chemistry to coordinate the first steps of DNA synthesis. Using DNA electrochemistry, we found that a change in oxidation state of the [4Fe4S] cluster acts as a switch for DNA binding. Single-atom mutations that inhibit this charge transfer hinder primase initiation without affecting primase structure or polymerization. Generating a
  
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• [Research Article] Cell-wide analysis of protein thermal unfolding reveals determinants of thermostability

  23-02-2017 23:57
  Temperature-induced cell death is thought to be due to protein denaturation, but the determinants of thermal sensitivity of proteomes remain largely uncharacterized. We developed a structural proteomic strategy to measure protein thermostability on a proteome-wide scale and with domain-level resolution. We applied it to Escherichia coli, Saccharomyces cerevisiae, Thermus thermophilus, and human cells, yielding thermostability data for more than 8000 proteins. Our results (i) indicate that temper
  
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• [Report] The cytotoxic Staphylococcus aureus PSMα3 reveals a cross-α amyloid-like fibril

  23-02-2017 23:57
  Amyloids are ordered protein aggregates, found in all kingdoms of life, and are involved in aggregation diseases as well as in physiological activities. In microbes, functional amyloids are often key virulence determinants, yet the structural basis for their activity remains elusive. We determined the fibril structure and function of the highly toxic, 22-residue phenol-soluble modulin α3 (PSMα3) peptide secreted by Staphylococcus aureus. PSMα3 formed elongated fibrils that shared the morpholo
  
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• [Report] Predicting human olfactory perception from chemical features of odor molecules

  23-02-2017 23:57
  It is still not possible to predict whether a given molecule will have a perceived odor or what olfactory percept it will produce. We therefore organized the crowd-sourced DREAM Olfaction Prediction Challenge. Using a large olfactory psychophysical data set, teams developed machine-learning algorithms to predict sensory attributes of molecules based on their chemoinformatic features. The resulting models accurately predicted odor intensity and pleasantness and also successfully predicted 8 among
  
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• [Report] Optical control of cell signaling by single-chain photoswitchable kinases

  23-02-2017 23:57
  Protein kinases transduce signals to regulate a wide array of cellular functions in eukaryotes. A generalizable method for optical control of kinases would enable fine spatiotemporal interrogation or manipulation of these various functions. We report the design and application of single-chain cofactor-free kinases with photoswitchable activity. We engineered a dimeric protein, pdDronpa, that dissociates in cyan light and reassociates in violet light. Attaching two pdDronpa domains at rationally
  
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• [Report] Combining polyethylene and polypropylene: Enhanced performance with PE/iPP multiblock polymers

  23-02-2017 23:57
  Polyethylene (PE) and isotactic polypropylene (iPP) constitute nearly two-thirds of the world’s plastic. Despite their similar hydrocarbon makeup, the polymers are immiscible with one another. Thus, common grades of PE and iPP do not adhere or blend, creating challenges for recycling these materials. We synthesized PE/iPP multiblock copolymers using an isoselective alkene polymerization initiator. These polymers can weld common grades of commercial PE and iPP together, depending on the molecul
  
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• [Report] Clonal hematopoiesis associated with TET2 deficiency accelerates atherosclerosis development in mice

  23-02-2017 23:57
  Human aging is associated with an increased frequency of somatic mutations in hematopoietic cells. Several of these recurrent mutations, including those in the gene encoding the epigenetic modifier enzyme TET2, promote expansion of the mutant blood cells. This clonal hematopoiesis correlates with an increased risk of atherosclerotic cardiovascular disease. We studied the effects of the expansion of Tet2-mutant cells in atherosclerosis-prone, low-density lipoprotein receptor–deficient (Ldlr–/
  
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• [Report] Bumblebees show cognitive flexibility by improving on an observed complex behavior

  23-02-2017 23:57
  We explored bees’ behavioral flexibility in a task that required transporting a small ball to a defined location to gain a reward. Bees were pretrained to know the correct location of the ball. Subsequently, to obtain a reward, bees had to move a displaced ball to the defined location. Bees that observed demonstration of the technique from a live or model demonstrator learned the task more efficiently than did bees observing a “ghost” demonstration (ball moved via magnet) or without demons
  
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• [Report] Antibiotic tolerance facilitates the evolution of resistance

  23-02-2017 23:57
  Controlled experimental evolution during antibiotic treatment can help to explain the processes leading to antibiotic resistance in bacteria. Recently, intermittent antibiotic exposures have been shown to lead rapidly to the evolution of tolerance—that is, the ability to survive under treatment without developing resistance. However, whether tolerance delays or promotes the eventual emergence of resistance is unclear. Here we used in vitro evolution experiments to explore this question. We fou
  
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• [Report] An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907

  23-02-2017 23:57
  Ultraluminous x-ray sources (ULXs) in nearby galaxies shine brighter than any x-ray source in our Galaxy. ULXs are usually modeled as stellar-mass black holes (BHs) accreting at very high rates or intermediate-mass BHs. We present observations showing that NGC 5907 ULX is instead an x-ray accreting neutron star (NS) with a spin period evolving from 1.43 seconds in 2003 to 1.13 seconds in 2014. It has an isotropic peak luminosity of ~1000 times the Eddington limit for a NS at 17.1 megaparsec. Sta
  
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• [Policy Forum] To slow or not? Challenges in subsecond networks

  23-02-2017 23:57
  Fall 2016 brought a fundamental change to the United States. Its fastest and largest network—the decentralized network of electronic market exchanges—began to experience its first ever intentional delay. Specifically, a 38-mile coil of fiber-optic cable was embedded into a new exchange network node, which, given the finite speed of light, introduced a systematic 350-µs (microsecond) delay in signal transmission (1). The future impacts this might have at the systems level are unknown.
  Author
  
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• [Perspective] Why tolerance invites resistance

  23-02-2017 23:57
  Bacteria use two strategies to avoid being killed by antibiotics: resistance and tolerance. Resistance mechanisms such as destruction of a drug or modification of its target allow bacteria to grow in the presence of antibiotics. Tolerance is a property of dormant, nongrowing bacterial cells in which antibiotic targets are inactive, allowing bacteria to survive. The two phenomena are mechanistically distinct and assumed to be unrelated. On page 826 of this issue, Levin-Reisman et al. (1) show tha
  
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• [Perspective] Thomas Crombie Schelling (1921–2016)

  23-02-2017 23:57
  Thomas Schelling, the distinguished economist, died on 13 December 2016 at his home in Bethesda, Maryland. He was 95 years old. Schelling applied his prolific work in game theory to arms control and deterrence, negotiation strategy, and most recently, global warming. His strategic insights made the world a much safer place.
  Author: Richard Zeckhauser
  
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• [Perspective] Quantifying protein (dis)order

  23-02-2017 23:57
  Twenty-five years ago, Chothia predicted that the structural domains of all proteins can be classified into about 1000 folds (1). Later studies refined this number; however, scientists also found that some proteins or parts of proteins never assume a specific fold. These regions are called intrinsically unstructured or disordered (2). Oncogenes such as p53 or breast cancer 1 (BRCA1) contain long disordered stretches, and aggregation of the disordered α-synuclein is thought to underlie Parkinson
  
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• [Perspective] Molecular stitches for enhanced recycling of packaging

  23-02-2017 23:57
  Polymers made of even slightly different repeat units are usually immiscible and form materials with two separate phases, like oil and water. Not only do different polymers not mix, but the interfaces between them are very sharp and mechanically weak. This lack of interfacial strength poses a very serious challenge to the recycling of blends of different polymers and, notably, polyethylene (PE) and isotactic polypropylene (iPP), the two polymers most commonly found in the industrial and domestic
  
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• [Perspective] Hematopoietic stem cells gone rogue

  23-02-2017 23:57
  Cardiovascular disease is considered to be an aging-related disease and is the leading cause of death in the elderly in developed countries (1). As of 2013, 65% of deaths attributed to cardiovascular disease occurred among patients 75 years and older. A hallmark of aging is the accumulation of somatic DNA mutations in proliferative tissue. Although somatic mutations in the hematopoietic (blood cell) system are frequently observed in patients with hematological cancers, there is also a close corr
  
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• [Perspective] A Mesozoic aviary

  23-02-2017 23:57
  The evolution of birds from a group of small dinosaurs between 170 million and 150 million years ago has emerged as a textbook example of a major evolutionary transformation in the fossil record (1). The attainment of powered flight—that is, active flapping that generates thrust—has been widely regarded, sometimes explicitly but often implicitly, as a long evolutionary march in which natural selection progressively refined one subgroup of dinosaurs into ever-better aerialists. However, recen
  
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• [Letter] Photos belong in the taxonomic Code

  23-02-2017 23:57
  Authors: André Rinaldo Senna Garraffoni, André Victor Lucci Freitas
  
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• [Letter] Lee Rubin: Our mentor and role model

  23-02-2017 23:57
  Authors: Chantal Bazenet, Howard Desmond, Eric Frank, Patrick Doherty, Andreas Eilers, Christine Gatchalian, Marcie Glicksman, Piotr Graczyk, Fabian Gusovsky, Jonathan Ham, David Kaplan, Michael Klymkoswsky, Karen Kotkow, Richard Krolewski, Paul Lang, Alison Linsley O'Neil, Mary Jane McCarthy, Karina Meiri, Freda Miller, Monica Mota Neumage, Ceren Ozek, Karen Philpott, Silvia Piccinotti, Feodor Price, Martin Raff, Marianne Ratcliffe, Jane Relton, Ken Rhodes, James Schwob, Caroline Smales, Terren
  
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• [Letter] Dams threaten rare Mekong dolphins

  23-02-2017 23:57
  Authors: Robert L. Brownell, Randall R. Reeves, Peter O. Thomas, Brian D. Smith, Gerard E. Ryan
  
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• [In Depth] California rains put spotlight on atmospheric rivers

  23-02-2017 23:57
  In just a few months, California has moved from extreme drought to dangerous flooding, thanks to atmospheric rivers: long, narrow ribbons of water vapor in the sky. Just a few hundred kilometers wide, atmospheric rivers stretch thousands of kilometers from the tropical oceans toward the poles, carrying up to 20 times as much water as the Mississippi River. That moisture gets tugged along by the windy paddle wheels of spinning storms ahead of its path. When the atmospheric rivers make landfall an
  
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• [Editors' Choice] Polarity reversal during tissue remodeling

  23-02-2017 23:57
  Author: Megan Eldred
  
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• [Editors' Choice] How tissues can take the heat

  23-02-2017 23:57
  Author: Laura M. Zahn
  
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• [Editors' Choice] How animals sense CO2 in blood

  23-02-2017 23:57
  Author: Julia Fahrenkamp-Uppenbrink
  
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• [Editors' Choice] DNA methylation curbs mast cell response

  23-02-2017 23:57
  Author: Priscilla Kelly
  
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• [Editors' Choice] CO2 reduction off base

  23-02-2017 23:57
  Author: Phil Szuromi
  
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• [Editors' Choice] An old motif with new specificity

  23-02-2017 23:57
  Author: Valda Vinson
  
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• [Editors' Choice] A supermassive black hole awakes

  23-02-2017 23:57
  Author: Keith M. Smith
  
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• [Editorial] Approving new drugs

  23-02-2017 23:57
  As the Trump administration takes shape, there is much speculation as to what major changes will be made. A dominant theme of the Trump campaign was to cut through bureaucracy in Washington, D.C., thereby enhancing innovation and bringing new technology to Americans more quickly. Nowhere could such a philosophical change have more impact than on Food and Drug Administration (FDA) approval of new drugs.
  Author: John L. LaMattina
  
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• [Association Affairs] New AAAS president emphasizes making the case for science

  23-02-2017 23:57
  Susan Hockfield has built support for major research initiatives
  Author: Michaela Jarvis
  
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• Scat secrets: Edmonton study explores role of predator poop in spreading plant seeds

  23-02-2017 23:44 via cbc.ca
  
  Some of the world's most ferocious predators — natural-born killers such as cougars and bears — are sort of gardeners in disguise, according to a new study from the University of Alberta.
  
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