When going to the movies with friends, one small action can make a big difference to be on the same page after the movie: eye contact. A simple conversation before the movie sets you up to be more in sync with your friends after the movie. These findings, being presented at the CNS conference in San Francisco, come from an unlikely place -- not the lab, or even a movie theater, but a classroom.
Researchers have identified more than 100 genes important for memory in people. The study, being presented at the CNS annual conference in San Francisco, is the first to identify correlations between gene data and brain activity during memory processing, providing a new window into human memory. It is part of the nascent but growing field of 'imaging genetics,' which aims to relate genetic variation to variation in brain anatomy and function.
Study is the latest in the long-running dispute over which lineage — sponges or comb jellies — is the oldest branch in the animal tree.
Nature News doi: 10.1038/nature.2017.21703
Collision sent billion-Sun-sized object speeding away from galactic core
Today's selection of need-to-know updates from the world of physics
We describe an approach to bottom-up fabrication that allows integration of the functional diversity of proteins into designed three-dimensional structural frameworks. A set of custom staple proteins based on transcription activator–like effector proteins folds a double-stranded DNA template into a user-defined shape. Each staple protein is designed to recognize and closely link two distinct double-helical DNA sequences at separate positions on the template. We present design rules for constructing megadalton-scale DNA-protein hybrid shapes; introduce various structural motifs, such as custom curvature, corners, and vertices; and describe principles for creating multilayer DNA-protein objects with enhanced rigidity. We demonstrate self-assembly of our hybrid nanostructures in one-pot mixtures that include the genetic information for the designed proteins, the template DNA, RNA polymerase, ribosomes, and cofactors for transcription and translation.
Authors: Florian Praetorius, Hendrik Dietz
Volcanoes are an expression of their underlying magmatic systems. Over the past three decades, the classical focus on upper crustal magma chambers has expanded to consider magmatic processes throughout the crust. A transcrustal perspective must balance slow (plate tectonic) rates of melt generation and segregation in the lower crust with new evidence for rapid melt accumulation in the upper crust before many volcanic eruptions. Reconciling these observations is engendering active debate about the physical state, spatial distribution, and longevity of melt in the crust. Here we review evidence for transcrustal magmatic systems and highlight physical processes that might affect the growth and stability of melt-rich layers, focusing particularly on conditions that cause them to destabilize, ascend, and accumulate in voluminous but ephemeral shallow magma chambers.
Authors: Katharine V. Cashman, R. Stephen J. Sparks, Jonathan D. Blundy
Neural activity in vivo is primarily measured using extracellular somatic spikes, which provide limited information about neural computation. Hence, it is necessary to record from neuronal dendrites, which can generate dendritic action potentials (DAPs) in vitro, which can profoundly influence neural computation and plasticity. We measured neocortical sub- and suprathreshold dendritic membrane potential (DMP) from putative distal-most dendrites using tetrodes in freely behaving rats over multiple days with a high degree of stability and submillisecond temporal resolution. DAP firing rates were several-fold larger than somatic rates. DAP rates were also modulated by subthreshold DMP fluctuations, which were far larger than DAP amplitude, indicating hybrid, analog-digital coding in the dendrites. Parietal DAP and DMP exhibited egocentric spatial maps comparable to pyramidal neurons. These results have important implications for neural coding and plasticity.
Authors: Jason J. Moore, Pascal M. Ravassard, David Ho, Lavanya Acharya, Ashley L. Kees, Cliff Vuong, Mayank R. Mehta
Transport of fluid through a pipe is essential for the operation of macroscale machines and microfluidic devices. Conventional fluids only flow in response to external pressure. We demonstrate that an active isotropic fluid, composed of microtubules and molecular motors, autonomously flows through meter-long three-dimensional channels. We establish control over the magnitude, velocity profile, and direction of the self-organized flows and correlate these to the structure of the extensile microtubule bundles. The inherently three-dimensional transition from bulk-turbulent to confined-coherent flows occurs concomitantly with a transition in the bundle orientational order near the surface and is controlled by a scale-invariant criterion related to the channel profile. The nonequilibrium transition of confined isotropic active fluids can be used to engineer self-organized soft machines.
Authors: Kun-Ta Wu, Jean Bernard Hishamunda, Daniel T. N. Chen, Stephen J. DeCamp, Ya-Wen Chang, Alberto Fernández-Nieves, Seth Fraden, Zvonimir Dogic
N-methyl-d-aspartate receptors (NMDARs) are heterotetrameric ion channels assembled as diheteromeric or triheteromeric complexes. Here, we report structures of the triheteromeric GluN1/GluN2A/GluN2B receptor in the absence or presence of the GluN2B-specific allosteric modulator Ro 25-6981 (Ro), determined by cryogenic electron microscopy (cryo-EM). In the absence of Ro, the GluN2A and GluN2B amino-terminal domains (ATDs) adopt “closed” and “open” clefts, respectively. Upon binding Ro, the GluN2B ATD clamshell transitions from an open to a closed conformation. Consistent with a predominance of the GluN2A subunit in ion channel gating, the GluN2A subunit interacts more extensively with GluN1 subunits throughout the receptor, in comparison with the GluN2B subunit. Differences in the conformation of the pseudo-2-fold–related GluN1 subunits further reflect receptor asymmetry. The triheteromeric NMDAR structures provide the first view of the most common NMDA receptor assembly and show how incorporation of two different GluN2 subunits modifies receptor symmetry and subunit interactions, allowing each subunit to uniquely influence receptor structure and function, thus increasing receptor complexity.
Authors: Wei Lü, Juan Du, April Goehring, Eric Gouaux
Nine months since the British vote to exit the European Union (“Brexit”), the UK science community's initial dismay has given way to hard-boiled determination to limit the damage it will do to universities and research. On 29 March, Prime Minister Theresa May is expected to give formal notification of the UK's intention to withdraw under Article 50 of the Lisbon Treaty, the constitutional basis of the EU. This will set in motion a 2-year period of intense negotiation on the terms of the UK's divorce, and any future agreements with the EU—with research just one line item on a long list of issues to be resolved.
Author: James Wilsdon
In science news around the world, the San people of Southern Africa release a code of ethics to guide researchers wanting to study their culture or genes, a series of films documenting nuclear tests from the 1945 to 1962 is released on YouTube, U.K. regulators grant the first license for mitochondrial replacement therapy, a researcher is accused of putting his name to a paper partially ghost-written by employees at chemical giant Monsanto, and more. Also, the administration of U.S. President Donald Trump will reopen a review of a 2012 fuel efficiency agreement by automakers that would double efficiency by 2025. And the Trump administration also plans to rescind an Obama-era rule requiring public disclosure of the chemicals used in fracking on public lands.
The 2018 budget proposal that President Donald Trump unveiled last week confirms two things that U.S. scientists have long suspected: The new president is no fan of research, and his administration has no overarching strategy for funding science. Deep proposed cuts to research at several agencies offer evidence that Trump doesn't see science—of any kind—as a spending priority. And along with neglect there's indifference. There's no telling how the National Science Foundation would fare, for example, because the budget blueprint doesn't mention it. In the meantime, scientists are also worried about the fate of this year's research budgets after Trump proposed cuts to the category that funds all civilian research. More angst: There's no word yet on whether the president will even appoint a science adviser, much less when he will fill dozens of senior slots at research agencies.
Author: Jeffrey Mervis
Two new clinical trials are testing whether flu vaccines increase the effectiveness of in vitro fertilization (IVF). The studies draw on new discoveries about the immune system's role in reproduction. Doctors used to think that the immune system had to shut down during pregnancy so that it wouldn't destroy the embryo. Now, researchers realize that the immune system remains active but learns to accept the embryo, developing what's known as tolerance. The trials will test whether flu shots increase tolerance toward the embryo and improve the success rate of IVF. One trial includes women undergoing IVF with embryos created from their own eggs, and the other trial includes women who receive embryos created from donor eggs.
Author: Mitch Leslie
A new study gives the long-standing dinosaur family tree an overhaul. Based on analyses of hundreds of traits gleaned from existing studies and fossils, the study strikes down a fundamental split of dinosaurs into "bird-hipped" and "reptile-hipped"; it also shifts the charismatic theropods—the group that includes Tyrannosaurus rex and eventually gave rise to birds—to a new spot on the tree, closer to the bird-hipped dinos. The reorganization of the tree suggests that hypercarnivory evolved in different groups through convergent evolution, and may upend the picture of where dinosaurs arose. But don't throw out your dog-eared dino books just yet, other researchers caution: This new family tree is likely to be debated for some time to come.
Author: Carolyn Gramling
A reassuring rule of thumb about earthquakes is breaking down. For decades, seismologists had assumed that individual faults—as well as isolated segments of longer faults—rupture independently of one another. That limits the maximum size of the potential earthquake that a fault zone can generate. But the magnitude-7.8 earthquake that struck New Zealand just after midnight on 14 November 2016—among the largest in the islands' modern history—has reduced that thinking to rubble. According to a new study, published online this week in Science, the heavy shaking in the Kaikoura quake was amassed by ruptures on at least 12 different faults, in some cases so far apart that they were thought to be immune to each other's influence.
Author: Betsy Mason
Scientists hunting unseen dark matter are looking deeper into the shadows. With searches for a favored dark matter candidate—weakly interacting massive particles (WIMPs)—coming up empty, physicists are now turning to the hypothetical "dark sector": an entire shadow realm of hidden particles. This week, physicists will meet at the University of Maryland in College Park for a workshop, sponsored by the U.S. Department of Energy (DOE), to mull ideas for a possible $10 million short-term experiment that would complement the agency's current WIMP search and other dark-matter efforts. And many researchers believe DOE should focus on the dark sector. Whereas WIMPs would be a single massive particle tacked onto the standard model of known particles, the dark sector would consist of a slew of lighter particles and forces—such as a dark version of electromagnetism—with tenuous connections to known particles. To spot dark-sector particles, physicists will have to rethink their detection techniques, but the new experiment could be small and cheap, physicists say. Still, DOE officials warn that the $10 million isn't a sure thing.
Author: Adrian Cho
A small fix made in the name of "stockpile stewardship" is turning U.S. submarine–launched missiles into more precise weapons. An improved mechanism installed in aging warhead now makes it possible to adjust the height at which they detonate, according to three experts writing in The Bulletin of the Atomic Scientists. This vastly increases the weapons' efficiency, the experts say, creating the impression that submarine-launched weapons could be used in a first strike against Russia's fixed missile silos. About 500 such warheads have been deployed on submarines; more than 1000 updated warheads are in production. The innovation could create "a deeply destabilizing and dangerous strategic nuclear situation," the authors warn.
Author: Eliot Marshall
Two Swedish fish researchers, with the aid of five colleagues elsewhere in the world, have alleged fraud in a study on the effects of microplastics on larval fish published in Science by two scientists at Uppsala University (UU) in June 2016. The study supposedly took place at the Ar Research Station in Gotland, but the whistleblowers say it never happened, based on eyewitness testimony and other evidence. A preliminary investigation by UU dismissed the claims in August 2016; a second investigation, by an expert panel at Sweden's Central Ethical Review Board, is still ongoing. An expert hired by that panel filed a more damning report last February that raised the possibility of fraud. Now, both sides are awaiting the expert panel's final verdict, which may influence an ongoing debate about how Swedish institutions investigate research misconduct.
Author: Martin Enserink