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Proceedings of the National Academy of Sciences

Glacial/interglacial wetland, biomass burning, and geologic methane emissions...
Atmospheric methane (CH4) records reconstructed from polar ice cores represent an integrated view on processes predominantly taking place in the terrestrial biogeosphere. Here, we present dual stable isotopic methane records [?13CH4 and ?D(CH4)] from four Antarctic ice cores, which provide improved ...

Hepatic ZIP14-mediated zinc transport is required for adaptation to endoplasm...
Extensive endoplasmic reticulum (ER) stress damages the liver, causing apoptosis and steatosis despite the activation of the unfolded protein response (UPR). Restriction of zinc from cells can induce ER stress, indicating that zinc is essential to maintain normal ER function. However, a role for zin...

Changes in E-cadherin rigidity sensing regulate cell adhesion [Cell Biology]
Mechanical cues are sensed and transduced by cell adhesion complexes to regulate diverse cell behaviors. Extracellular matrix (ECM) rigidity sensing by integrin adhesions has been well studied, but rigidity sensing by cadherins during cell adhesion is largely unexplored. Using mechanically tunable p...

E-cadherin and LGN align epithelial cell divisions with tissue tension indepe...
Tissue morphogenesis requires the coordinated regulation of cellular behavior, which includes the orientation of cell division that defines the position of daughter cells in the tissue. Cell division orientation is instructed by biochemical and mechanical signals from the local tissue environment, b...

FANCM, BRCA1, and BLM cooperatively resolve the replication stress at the ALT...
In the mammalian genome, certain genomic loci/regions pose greater challenges to the DNA replication machinery (i.e., the replisome) than others. Such known genomic loci/regions include centromeres, common fragile sites, subtelomeres, and telomeres. However, the detailed mechanism of how mammalian c...

High serum serotonin in sudden infant death syndrome [Medical Sciences]
Sudden infant death syndrome (SIDS), the leading cause of postneonatal infant mortality, likely comprises heterogeneous disorders with the common phenotype of sudden death without explanation upon postmortem investigation. Previously, we reported that ?40% of SIDS deaths are associated with abnormal...

Endogenous orienting in the archer fish [Neuroscience]
The literature has long emphasized the neocortex?s role in volitional processes. In this work, we examined endogenous orienting in an evolutionarily older species, the archer fish, which lacks neocortex-like cells. We used Posner?s classic endogenous cuing task, in which a centrally presented, spati...

Improved color constancy in honey bees enabled by parallel visual projections...
How can a pollinator, like the honey bee, perceive the same colors on visited flowers, despite continuous and rapid changes in ambient illumination and background color? A hundred years ago, von Kries proposed an elegant solution to this problem, color constancy, which is currently incorporated in m...

Quantification of habitat fragmentation reveals extinction risk in terrestria...
Although habitat fragmentation is often assumed to be a primary driver of extinction, global patterns of fragmentation and its relationship to extinction risk have not been consistently quantified for any major animal taxon. We developed high-resolution habitat fragmentation models and used phylogen...

Global priorities for conservation across multiple dimensions of mammalian di...
Conservation priorities that are based on species distribution, endemism, and vulnerability may underrepresent biologically unique species as well as their functional roles and evolutionary histories. To ensure that priorities are biologically comprehensive, multiple dimensions of diversity must be ...

Correction for Bahari-Javan et al., HDAC1 links early life stress to schizoph...
NEUROSCIENCE Correction for ?HDAC1 links early life stress to schizophrenia-like phenotypes,? by Sanaz Bahari-Javan, Hristo Varbanov, Rashi Halder, Eva Benito, Lalit Kaurani, Susanne Burkhardt, Heike Anderson-Schmidt, Ion Anghelescu, Monika Budde, Roman M. Stilling, Joan Costa, Juan Medina, Detlef E...

Protect coastal wetlands in China to save endangered migratory birds [Biologi...
Evaluating the significance of protected areas for biodiversity and ecosystem services is important for nature conservation. In a recent issue of PNAS, Xu et al. (1) present valuable information on provision of biodiversity and ecosystem services by China?s nature reserves. They conclude that reserv...

QnAs with Karel Svoboda [QnAs]
When Karel Svoboda describes his decades-long efforts to visualize the brain with ever-greater precision, the unmistakable impression is that of a man driven by an insatiable urge to expand the frontiers of technology in the service of science. Since the mid-1990s, when he and his colleagues develop...

QnAs with Rodolphe Barrangou [QnAs]
The past decade in biological research might well be christened the age of CRISPR, a once-curious feature of bacterial genomes that spawned a handy tool for editing genes. Using CRISPR-based tools, researchers are making leaps in basic clinical research, and biotechnology companies are racing to lau...

Tracking LINE1 retrotransposition in the germline [Genetics]
Nearly half of the mammalian genome is occupied by repetitive transposon elements, including long-interspersed nuclear elements (LINEs), short-interspersed nuclear elements, and long terminal repeat retrotransposons. The ability of these transposable elements to propagate and insert randomly through...

Tetragonal CH3NH3PbI3 is ferroelectric [Applied Physical Sciences]
Halide perovskite (HaP) semiconductors are revolutionizing photovoltaic (PV) solar energy conversion by showing remarkable performance of solar cells made with HaPs, especially tetragonal methylammonium lead triiodide (MAPbI3). In particular, the low voltage loss of these cells implies a remarkably ...

Notch1 maintains dormancy of olfactory horizontal basal cells, a reserve neur...
The remarkable capacity of the adult olfactory epithelium (OE) to regenerate fully both neurosensory and nonneuronal cell types after severe epithelial injury depends on life-long persistence of two stem cell populations: the horizontal basal cells (HBCs), which are quiescent and held in reserve, an...

Antagonistic BMP-cWNT signaling in the cnidarian Nematostella vectensis revea...
Gastrulation was arguably the key evolutionary innovation that enabled metazoan diversification, leading to the formation of distinct germ layers and specialized tissues. Differential gene expression specifying cell fate is governed by the inputs of intracellular and/or extracellular signals. Beta-c...

Disentangling the effects of selection and loss bias on gene dynamics [Evolut...
We combine mathematical modeling of genome evolution with comparative analysis of prokaryotic genomes to estimate the relative contributions of selection and intrinsic loss bias to the evolution of different functional classes of genes and mobile genetic elements (MGE). An exact solution for the dyn...

Multiparity improves outcomes after cerebral ischemia in female mice despite ...
Females show a varying degree of ischemic sensitivity throughout their lifespan, which is not fully explained by hormonal or genetic factors. Epidemiological data suggest that sex-specific life experiences such as pregnancy increase stroke risk. This work evaluated the role of parity on stroke outco...

Simulating tactile signals from the whole hand with millisecond precision [Ne...
When we grasp and manipulate an object, populations of tactile nerve fibers become activated and convey information about the shape, size, and texture of the object and its motion across the skin. The response properties of tactile fibers have been extensively characterized in single-unit recordings...

Mechanochemical feedback underlies coexistence of qualitatively distinct cell...
Cell polarization and directional cell migration can display random, persistent, and oscillatory dynamic patterns. However, it is not clear whether these polarity patterns can be explained by the same underlying regulatory mechanism. Here, we show that random, persistent, and oscillatory migration a...

Chimpanzee super strength and human skeletal muscle evolution [Anthropology]
Since at least the 1920s, it has been reported that common chimpanzees (Pan troglodytes) differ from humans in being capable of exceptional feats of ?super strength,? both in the wild and in captive environments. A mix of anecdotal and more controlled studies provides some support for this view; how...

Experimental evolution reveals an effective avenue to release catabolite repr...
Microbial production of fuels and chemicals from lignocellulosic biomass provides promising biorenewable alternatives to the conventional petroleum-based products. However, heterogeneous sugar composition of lignocellulosic biomass hinders efficient microbial conversion due to carbon catabolite repr...

High-speed acoustic communication by multiplexing orbital angular momentum [A...
Long-range acoustic communication is crucial to underwater applications such as collection of scientific data from benthic stations, ocean geology, and remote control of off-shore industrial activities. However, the transmission rate of acoustic communication is always limited by the narrow-frequenc...

Traces of surfactants can severely limit the drag reduction of superhydrophob...
Superhydrophobic surfaces (SHSs) have the potential to achieve large drag reduction for internal and external flow applications. However, experiments have shown inconsistent results, with many studies reporting significantly reduced performance. Recently, it has been proposed that surfactants, ubiqu...

Aridity and hominin environments [Earth, Atmospheric, and Planetary Sciences]
Aridification is often considered a major driver of long-term ecological change and hominin evolution in eastern Africa during the Plio-Pleistocene; however, this hypothesis remains inadequately tested owing to difficulties in reconstructing terrestrial paleoclimate. We present a revised aridity ind...

Varying and unchanging whiteness on the wings of dusk-active and shade-inhabi...
Whiteness, although frequently apparent on the wings, legs, antennae, or bodies of many species of moths and butterflies, along with other colors and shades, has often escaped our attention. Here, we investigate the nanostructure and microstructure of white spots on the wings of Carystoides escalant...

Evolution of nonspectral rhodopsin function at high altitudes [Evolution]
High-altitude environments present a range of biochemical and physiological challenges for organisms through decreases in oxygen, pressure, and temperature relative to lowland habitats. Protein-level adaptations to hypoxic high-altitude conditions have been identified in multiple terrestrial endothe...

Evolution of immune chemoreceptors into sensors of the outside world [Evolution]
Changes in gene expression patterns represent an essential source of evolutionary innovation. A striking case of neofunctionalization is the acquisition of neuronal specificity by immune formyl peptide receptors (Fprs). In mammals, Fprs are expressed by immune cells, where they detect pathogenic and...

Nonenzymatic gluconeogenesis-like formation of fructose 1,6-bisphosphate in i...
The evolutionary origins of metabolism, in particular the emergence of the sugar phosphates that constitute glycolysis, the pentose phosphate pathway, and the RNA and DNA backbone, are largely unknown. In cells, a major source of glucose and the large sugar phosphates is gluconeogenesis. This ancien...

Chimpanzees return favors at a personal cost [Psychological and Cognitive Sci...
Humans regularly provide others with resources at a personal cost to themselves. Chimpanzees engage in some cooperative behaviors in the wild as well, but their motivational underpinnings are unclear. In three experiments, chimpanzees (Pan troglodytes) always chose between an option delivering food ...

Poor caregiver mental health predicts mortality of patients with neurodegener...
Dementia and other neurodegenerative diseases cause profound declines in functioning; thus, many patients require caregivers for assistance with daily living. Patients differ greatly in how long they live after disease onset, with the nature and severity of the disease playing an important role. Car...

Free will beliefs predict attitudes toward unethical behavior and criminal pu...
Do free will beliefs influence moral judgments? Answers to this question from theoretical and empirical perspectives are controversial. This study attempted to replicate past research and offer theoretical insights by analyzing World Values Survey data from residents of 46 countries (n = 65,111 pers...

Reconstruction and evolutionary history of eutherian chromosomes [Evolution]
Whole-genome assemblies of 19 placental mammals and two outgroup species were used to reconstruct the order and orientation of syntenic fragments in chromosomes of the eutherian ancestor and six other descendant ancestors leading to human. For ancestral chromosome reconstructions, we developed an al...

Stem caecilian from the Triassic of Colorado sheds light on the origins of Li...
The origin of the limbless caecilians remains a lasting question in vertebrate evolution. Molecular phylogenies and morphology support that caecilians are the sister taxon of batrachians (frogs and salamanders), from which they diverged no later than the early Permian. Although recent efforts have d...

The Red Queen and King in finite populations [Evolution]
In antagonistic symbioses, such as host?parasite interactions, one population?s success is the other?s loss. In mutualistic symbioses, such as division of labor, both parties can gain, but they might have different preferences over the possible mutualistic arrangements. The rates of evolution of the...

Structural complexity and molecular heterogeneity of a butterfly ejaculate re...
Male ejaculates are often structurally complex, and this complexity is likely to influence key reproductive interactions between males and females. However, despite its potential evolutionary significance, the molecular underpinnings of ejaculate structural complexity have received little empirical ...

Evolutionary radiation of lanthipeptides in marine cyanobacteria [Evolution]
Lanthipeptides are ribosomally derived peptide secondary metabolites that undergo extensive posttranslational modification. Prochlorosins are a group of lanthipeptides produced by certain strains of the ubiquitous marine picocyanobacteria Prochlorococcus and Synechococcus. Unlike other lanthipeptide...

Multiple layers of heterogeneity and subset diversity in human MAIT cell resp...
Mucosa-associated invariant T (MAIT) cells are a large innate-like T-cell subset in humans defined by invariant TCR V?7.2 use and expression of CD161. MAIT cells recognize microbial riboflavin metabolites of bacterial or fungal origin presented by the monomorphic MR1 molecule. The extraordinary leve...

Hypocretin (orexin) is critical in sustaining theta/gamma-rich waking behavio...
Hcrt gene inactivation in mice leads to behavioral state instability, abnormal transitions to paradoxical sleep, and cataplexy, hallmarks of narcolepsy. Sleep homeostasis is, however, considered unimpaired in patients and narcoleptic mice. We find that whereas Hcrtko/ko mice respond to 6-h sleep dep...

Sex-specific early survival drives adult sex ratio bias in snowy plovers and ...
Adult sex ratio (ASR) is a central concept in population biology and a key factor in sexual selection, but why do most demographic models ignore sex biases? Vital rates often vary between the sexes and across life history, but their relative contributions to ASR variation remain poorly understood?an...

Monte Carlo sampling for stochastic weight functions [Applied Mathematics]
Conventional Monte Carlo simulations are stochastic in the sense that the acceptance of a trial move is decided by comparing a computed acceptance probability with a random number, uniformly distributed between 0 and 1. Here, we consider the case that the weight determining the acceptance probabilit...

Toll-like receptor pathway evolution in deuterostomes [Evolution]
Animals have evolved an array of pattern-recognition receptor families essential for recognizing conserved molecular motifs characteristic of pathogenic microbes. One such family is the Toll-like receptors (TLRs). On pathogen binding, TLRs initiate specialized cytokine signaling catered to the class...

Population-genomic inference of the strength and timing of selection against ...
The interplay of divergent selection and gene flow is key to understanding how populations adapt to local environments and how new species form. Here, we use DNA polymorphism data and genome-wide variation in recombination rate to jointly infer the strength and timing of selection, as well as the ba...

Evolutionary strata on young mating-type chromosomes despite the lack of sexu...
Sex chromosomes can display successive steps of recombination suppression known as ?evolutionary strata,? which are thought to result from the successive linkage of sexually antagonistic genes to sex-determining genes. However, there is little evidence to support this explanation. Here we investigat...

IL-2 therapy restores regulatory T-cell dysfunction induced by calcineurin in...
CD4+CD25+FOXP3+ Tregs constitute a heterogeneous lymphocyte subpopulation essential for curtailing effector T cells and establishing peripheral tolerance. Calcineurin inhibitors (CNIs) are among the most effective agents in controlling effector T-cell responses in humans. However, CNIs also reduce t...

Childhood social class and cognitive aging in the Swedish Adoption/Twin Study...
In this report we analyzed genetically informative data to investigate within-person change and between-person differences in late-life cognitive abilities as a function of childhood social class. We used data from nine testing occasions spanning 28 y in the Swedish Adoption/Twin Study of Aging and ...