Two reports highlight the plight of postdocs on both sides of the pond aiming for academia.
The United States and other countries have made huge investments in fracking, but forecasts of production may be vastly overestimated.
Research into climate engineering must proceed — even if it turns out to be unnecessary.
With trials under way, scientists are working out how to give vaccines in affected regions.
The Karolinska Institute is carrying out two inquiries into an experimental transplant procedure.
Archaeopteryx’s status is changing, but the animal is still key to the dinosaur–bird transition.
Geoengineers meet to work out what research is acceptable.
Researchers gather data on innovative uses of cancer treatments.
After a 30-year struggle to harness quantum weirdness for computing, physicists finally have their goal in reach.
The United States is banking on decades of abundant natural gas to power its economic resurgence. That may be wishful thinking.
News & Views
Two studies find that an intracellular quality-control mechanism called autophagy is regulated by nuclear receptor proteins that govern the expression of autophagy genes. See Letters p.108 & p.112
Concentrations of heavy isotopes of hydrogen and oxygen decrease in rain as storms cross land. A model examines the transport of water vapour that causes this effect, and provides insight into past and present climates.
The finding that intestinal viruses can substitute for intestinal bacteria to promote the health of their mammalian hosts raises the possibility that viruses in the gut may be beneficial in some circumstances. See Letter p.94
Galaxies contain fewer stars than predicted. The discovery of a massive galactic outflow of molecular gas in a compact galaxy, which forms stars 100 times faster than the Milky Way, may help to explain why. See Letter p.68
Chronic stress can cause depression in some individuals, but leaves others untouched. Engagement of a molecular pathway controlling the production of tiny RNA snippets might help to explain the difference. See Article p.51
An imaging technique has been developed that can record non-repetitive ultrafast phenomena without strobe or flash illumination. The approach could find applications in biomedicine and security technologies. See Letter p.74
An experiment shows that although bank employees behave honestly on average, their dishonesty increases when they make decisions after having been primed to think about their professional identity. See Letter p.86
A new class of fatty acid — found in food and synthesized by mammalian tissues — enhances glucose uptake from the blood and reduces inflammation, suggesting that these fats might be used to treat diabetes.
Here β-catenin, which has been implicated in neurological and psychiatric diseases, including depression, is shown to mediate resilience to chronic stress in mice through induction of Dicer and microRNAs in nucleus accumbens, a key brain reward region.
This study uses single-cell expression profiling of pluripotent stem cells after various perturbations, and uncovers a high degree of variability that can be inherited through cell divisions—modulating microRNA or external signalling pathways induces a ground state with reduced gene expression heterogeneity and a distinct chromatin profile.
Here the structure of the membrane protein complex sodium-translocating NADH:quinone oxidoreductase (Na+-NQR) is described; as Na+-NQR is a component of the respiratory chain of various bacteria, including pathogenic ones, this structure may serve as the basis for the development of new antibiotics.
A high-velocity outflow of molecular gas from a starburst galaxy has been observed to extend about ten kiloparsecs; its velocity is consistent with the momentum flux from stellar radiation pressure, showing that bursts of star formation can eject large amounts of cold gas from the central regions of galaxies, curtailing star formation.
Terahertz-frequency optical pulses can resonantly drive selected vibrational modes in solids and deform their crystal structures. In complex oxides, this method has been used to melt electronic order, drive insulator-to-metal transitions and induce superconductivity. Strikingly, coherent interlayer transport strongly reminiscent of superconductivity can be transiently induced up to room temperature (300 kelvin) in YBa2Cu3O6+x (refs 9, 10). Here we report the crystal structure of this exotic non-equilibrium state, determined by femtosecond X-ray diffraction and ab initio density functional theory calculations. We find that nonlinear lattice excitation in normal-state YBa2Cu3O6+x at above the transition temperature of 52 kelvin causes a simultaneous increase and decrease in the Cu–O2 intra-bilayer and, respectively, inter-bilayer distances, accompanied by anisotropic changes in the in-plane O–Cu–O bond buckling. Density functional theory calculations indicate that these motions cause drastic changes in the electronic structure. Among these, the enhancement in the character of the in-plane electronic structure is likely to favour superconductivity.
A technique based on compressed imaging with a streak camera is reported that can videotape transient events in two dimensions with temporal resolution down to tens of picoseconds, and its usefulness is demonstrated using single laser shots applied to a variety of physical phenomena.
Two-dimensional titanium carbide has been produced by etching out aluminium in a lithium fluoride and hydrochloric acid mixture; it is hydrophilic and mouldable like clay and has excellent volumetric capacitance and cyclability, properties that are desirable for portable electronics.
El Niño events can transfer subsurface heat to the eastern North Pacific with a delay of several months, causing the intensification of tropical cyclones; the mechanism may lead to insights into past variations in tropical cyclone intensity and enhance seasonal predictions.
According to popular opinion, unethical business practices are common in the financial industry; here, the employees of a large, international bank are shown to behave, on average, honestly in a laboratory game to reveal dishonest behaviour, but when their professional identity as bank employees was rendered salient, the prevalence of dishonest behaviour increased.
In roots and dark-grown hypocotyls of Arabidopsis thaliana, ABP1-mediated auxin signalling induces swift re-orientation of the microtubule cytoskeleton from transverse to longitudinal, thus inhibiting cell expansion.
Commensal bacteria are known to have an important role in keeping the host healthy, but the role of eukaryotic viruses has been unknown; now, persistent infection in mice with various strains of enteric norovirus is shown to provide similar host protection.
A new role for the endosomal sorting complex required for transport (ESCRT) is identified in fly larvae, where it is shown to be essential for the secretion and long-range signalling of the embryonic development morphogen Hedgehog.
Using advanced microscopy techniques, the process of centriole amplification in multiciliated cells is explored, and the daughter centriole identified as the primary nucleation site of more than 90% of the new centrioles, contesting existing de novo theories of centriolar amplification and highlighting a new centrosome asymmetry.
The FXR–CREB axis is identified as a key physiological switch that regulates autophagy during feeding/fasting cycles; in the fed state, the nuclear receptor FXR is shown to suppress autophagy in the liver by inhibiting autophagy-associated lipid breakdown triggered under fasting conditions by the transcriptional activator CREB.
The nuclear receptors FXR and PPARα are shown to regulate autophagy by competing for binding to shared sites in the promoters of autophagic genes; in the fed state FXR suppresses hepatic autophagy, whereas in the fasted state PPARα is activated and reverses the normal suppression of autophagy.
The RING finger protein TRIM37 is encoded by a gene that is amplified in certain breast cancers, but its function is unknown; here, it is shown to mono-ubiquitinate histone H2A and repress gene expression, and to function as a breast cancer oncoprotein.
Mice lacking the mechanically activated ion channel Piezo2 in both sensory neurons and Merkel cells are almost totally incapable of light-touch sensation while other somatosensory functions, such as mechanical nociception, remain intact, implying that other mechanically activated ion channels must now be identified to account for painful touch sensation.
Activation of mechanosensitive ion channels by physical force underlies many physiological processes including the sensation of touch, hearing and pain. TRAAK (also known as KCNK4) ion channels are neuronally expressed members of the two-pore domain K+ (K2P) channel family and are mechanosensitive. They are involved in controlling mechanical and temperature nociception in mice. Mechanosensitivity of TRAAK is mediated directly through the lipid bilayer—it is a membrane-tension-gated channel. However, the molecular mechanism of TRAAK channel gating and mechanosensitivity is unknown. Here we present crystal structures of TRAAK in conductive and non-conductive conformations defined by the presence of permeant ions along the conduction pathway. In the non-conductive state, a lipid acyl chain accesses the channel cavity through a 5 Å-wide lateral opening in the membrane inner leaflet and physically blocks ion passage. In the conductive state, rotation of a transmembrane helix (TM4) about a central hinge seals the intramembrane opening, preventing lipid block of the cavity and permitting ion entry. Additional rotation of a membrane interacting TM2–TM3 segment, unique to mechanosensitive K2Ps, against TM4 may further stabilize the conductive conformation. Comparison of the structures reveals a biophysical explanation for TRAAK mechanosensitivity—an expansion in cross-sectional area up to 2.7 nm2 in the conductive state is expected to create a membrane-tension-dependent energy difference between conformations that promotes force activation. Our results show how tension of the lipid bilayer can be harnessed to control gating and mechanosensitivity of a eukaryotic ion channel.