Highly pathogenic avian influenza viruses (HPAIVs) derive from H5 and 周论H7 low pathogenic avian influenza viruses (LPAIVs). Although insertion of a furin-cleavable multibasic cleavage site (MBCS) in the hemagglutinin gene was identified decades ago as the genetic basis for the LPAIV-to-HPAIV transition, the mechanisms underlying the occurrence of insertion are unknown. Here, we show that transient H5 RNA structures, predicted to trap the influenza virus polymerase on purine-rich sequences, drive nucleotide insertions, providing empirical evidence of RNA structure involvement in MBCS acquisition. Introduction of H5-like sequences and structures into an H6 hemagglutinin resulted in MBCS-yielding insertions. Our results show that nucleotide insertions that underlie H5 HPAIV emergence result from an RNA structure–driven diversity-generating mechanism, which could also occur in other RNA viruses.
Global warming is altering the fisheries that underpin food security, but projections of these impacts generally exclude evolutionary processes. We describe a model that forecasts how fish will adapt to future climates and the consequences of that evolution for fisheries yields. We predict that fish in warmer waters will grow faster but evolve earlier maturation, decreasing their maximum size. We predict that evolution ameliorates the impacts of climate change on fish fitness but exacerbates its impacts on fisheries yields—worsening losses by ~50%. Excluding evolution overestimates future yields under all emissions scenarios, but evolution’s impacts are greatest under the most extreme scenarios. All life histories may evolve in response to global change—this evolution should be considered in projections of ecosystems and their services.
动物学Zoology
Seal and sea lion brains have evolved to support volitional control of vocal behavior and learning
海豹和海狮的大脑已进化出支持自主发声控制以及发声学习的能力
▲ 作者：PETER F. COOK, ANDREW A. ROUSE, EVA SAWYER, KARLA MILLER AND GREGORY BERNS
Scavengers generally rely on patchily distributed, unpredictable carrion. A long-standing hypothesis suggests scavenging ravens reliably locate such food by directly following large carnivores to their kills. However, by satellite tracking 69 ravens, 20 wolves, and 11 cougars in Yellowstone National Park, we found that following of predators over large distances rarely occurred. Instead, ravens routinely revisited sites where wolf kills were common—returning from distances of up to 155 kilometers to find carrion. Much like navigating to permanent anthropogenic subsidies, ravens appear to remember potential sources of carrion shaped by previous encounters with wolves or their kills. These findings suggest that spatial memory and navigation play a considerably greater role than previously assumed among scavengers, and possibly other wide-ranging species, in search of ephemeral resources.
公共卫生Public Health
Polymerase trapping as the mechanism of H5 highly pathogenic avian influenza virus genesis
聚合酶捕获导致H5高致病性禽流感病毒产生
▲ 作者：MATHIS FUNK, MONIQUE I. SPRONKEN , ROY M. HUTCHINSON, BENOIT ARRAGAIN, PAULINE JUYOUX, THEO M. BESTEBROER, ET AL.
The growth and penetration of lithium dendrites through electrolytes and separators remain key challenges to realizing high–energy density lithium-metal batteries. Using mechanically strong electrolytes and separators has been considered a promising strategy based on the commonly believed softness of lithium. However, dendrite formation persists in stiff solid electrolytes, suggesting distinct mechanical behaviors. We measured the mechanical properties of individual lithium dendrites using an air-free protocol. We found that lithium dendrites are unexpectedly strong and brittle, with fracture stress greater than ~150 megapascals, unlike the ductile bulk metal. Cryo–transmission electron microscopy and mechanical modeling showed that this behavior arises from solid electrolyte interface constraints and nanoscale strengthening. These findings provide alternative mechanisms for dendrite penetration and dead lithium formation as well as guidance for design strategies for lithium-metal batteries.
环境科学Environmental Science
Rapid evolution predicts demographic recovery after extreme drought
快速进化可预测极端干旱后的种群数量复苏
▲ 作者：DANIEL N. ANSTETT, JULIA ANSTETT, SEEMA N. SHETH, DYLAN R. MOXLEY, HALEY A. BRANCH, MOJTABA JAHANI, ET AL.
Populations that are declining as a result of climate change may need to evolve to persist. Although evolutionary rescue has been demonstrated in theory and in the laboratory, its relevance to natural populations facing climate change remains unknown. Here we link rapid evolution and population dynamics in scarlet monkeyflower, Mimulus cardinalis, during exceptional drought. We leverage whole-genome sequencing across 55 populations to identify climate-associated loci. Simultaneously we track demography and allele frequency change throughout the drought. We establish range-wide population decline during the drought, geographically variable rapid evolution, and variable population recovery that is predictable by standing genetic variation in, and rapid evolution at, climate-associated loci. These findings demonstrate the possibility of evolutionary rescue in the wild, showing that genetic variation at adaptive, but not neutral, loci predicts population recovery.
Evolutionary adaptation to global change reduces sustainable fisheries yields
对全球变化的进化适应性降低了可持续渔业的捕捞产量
▲ 作者：TAN Koz?owski , DUSTIN J. MARSHALL AND CRAIG R. WHITE
Seals and sea lions have highly developed volitional breathing control, to which the phocid seals add vocal production learning, including mimicry. In this work, using histology and ex vivo diffusion magnetic resonance imaging tractography, we provide evidence for a phylogenetic spectrum of accumulative neural adaptations supporting aspects of volitional vocal control across pinnipeds. Otariids and phocid seals, but not coyotes, have a direct connection between the vocal motor cortex and phonatory brainstem nuclei. Harbor seals showed hypertrophic connectivity between the anterior ventrolateral thalamus and the vocal premotor cortex—part of a forebrain circuit related to vocal learning in birds and mimicry in humans and parrots. We demonstrate that phocid seals have auditory-premotor pathways potentially related to developmental call learning.
Ravens anticipate wolf kill sites across broad scales
乌鸦预测大规模的狼群捕杀地点
▲ 作者：MATTHIAS-CLAUDIO LORETTO, KRISTINA B. BECK, DOUGLAS W. SMITH, DANIEL R. STAHLER, LAUREN E. WALKER, MARTIN WIKELSKI, ET AL.
