Linking the pseudogap in the cuprates with local symmetry breaking: A commentary [Physics]
In the last 2 decades, increasingly precise measurements have established that the cuprate high-temperature superconductors exhibit numerous ordering tendencies. In addition to the “big 2”—Néel antiferromagnetism (AF) and d-wave superconductivity (SC)—a variety of other orders have been observed, especially in the enigmatic “pseudogap” regime of the phase diagram. The term... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: S. A. Kivelson, Samuel Lederer Tags: Commentaries Source Type: research

Supermolecules steer electrons down a wrong-way street [Chemistry]
The controlled movement of electrons is of paramount importance for solving current technological problems that will have broad societal impact. Batteries for electric vehicles, quantum computers, efficient solar energy conversion devices, and nanoscale machines for biomedical applications represent just a handful of such possible advances. A current research thrust is... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Malcolm D. E. Forbes Tags: Commentaries Source Type: research

Domesticated species: It takes one to know one [Evolution]
Darwin was fascinated by both the process and outcome of our own species’ efforts toward the domestication of the plethora of others that became so central to our unparalleled success (1). In fact, he documented many of the various traits and behaviors that we have so purposefully selected. He was... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Mary Ann Raghanti Tags: Commentaries Source Type: research

Neuroscience for architecture: The evolving science of perceptual meaning [Psychological and Cognitive Sciences]
Besides its traditional reliance on the tacit knowledge of timeless practices of construction, architecture relies largely on theories and findings of other areas of research and knowledge, instead of possessing an independent theoretical foundation of its own. During the past decades, architecture has been viewed from various theoretical perspectives, provided... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Sergei Gepshtein, Joseph Snider Tags: Commentaries Source Type: research

Nonparametric inference of interaction laws in systems of agents from trajectory data [Applied Mathematics]
Inferring the laws of interaction in agent-based systems from observational data is a fundamental challenge in a wide variety of disciplines. We propose a nonparametric statistical learning approach for distance-based interactions, with no reference or assumption on their analytical form, given data consisting of sampled trajectories of interacting agents. We... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Fei Lu, Ming Zhong, Sui Tang, Mauro Maggioni Tags: PNAS Plus Source Type: research

Motile curved bacteria are Pareto-optimal [Biophysics and Computational Biology]
Curved rods are a ubiquitous bacterial phenotype, but the fundamental question of why they are shaped this way remains unanswered. Through in silico experiments, we assessed freely swimming straight- and curved-rod bacteria of a wide diversity of equal-volume shapes parameterized by elongation and curvature, and predicted their performances in tasks... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Rudi Schuech, Tatjana Hoehfurtner, David J. Smith, Stuart Humphries Tags: PNAS Plus Source Type: research

High-frequency microrheology in 3D reveals mismatch between cytoskeletal and extracellular matrix mechanics [Biophysics and Computational Biology]
Mechanical homeostasis describes how cells sense physical cues from the microenvironment and concomitantly remodel both the cytoskeleton and the surrounding extracellular matrix (ECM). Such feedback is thought to be essential to healthy development and maintenance of tissue. However, the nature of the dynamic coupling between microscale cell and ECM mechanics... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Jack R. Staunton, Woong Young So, Colin D. Paul, Kandice Tanner Tags: PNAS Plus Source Type: research

Ambidextrous helical nanotubes from self-assembly of designed helical hairpin motifs [Chemistry]
Tandem repeat proteins exhibit native designability and represent potentially useful scaffolds for the construction of synthetic biomimetic assemblies. We have designed 2 synthetic peptides, HEAT_R1 and LRV_M3Δ1, based on the consensus sequences of single repeats of thermophilic HEAT (PBS_HEAT) and Leucine-Rich Variant (LRV) structural motifs, respectively. Self-assembly of the peptides... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Spencer A. Hughes, Fengbin Wang, Shengyuan Wang, Mark A. B. Kreutzberger, Tomasz Osinski, Albina Orlova, Joseph S. Wall, Xiaobing Zuo, Edward H. Egelman, Vincent P. Conticello Tags: PNAS Plus Source Type: research

Gas phase formation of c-SiC3 molecules in the circumstellar envelope of carbon stars [Chemistry]
Complex organosilicon molecules are ubiquitous in the circumstellar envelope of the asymptotic giant branch (AGB) star IRC+10216, but their formation mechanisms have remained largely elusive until now. These processes are of fundamental importance in initiating a chain of chemical reactions leading eventually to the formation of organosilicon molecules—among them key... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Tao Yang, Luke Bertels, Beni B. Dangi, Xiaohu Li, Martin Head-Gordon, Ralf I. Kaiser Tags: PNAS Plus Source Type: research

Redox control on nitrogen isotope fractionation during planetary core formation [Earth, Atmospheric, and Planetary Sciences]
The present-day nitrogen isotopic compositions of Earth’s surficial (15N-enriched) and deep reservoirs (15N-depleted) differ significantly. This distribution can neither be explained by modern mantle degassing nor recycling via subduction zones. As the effect of planetary differentiation on the behavior of N isotopes is poorly understood, we experimentally determined N-isotopic fractionations... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Celia Dalou, Evelyn Furi, Cecile Deligny, Laurette Piani, Marie–Camille Caumon, Mickael Laumonier, Julien Boulliung, Mattias Eden Tags: PNAS Plus Source Type: research

A modern maximum-likelihood theory for high-dimensional logistic regression [Statistics]
Students in statistics or data science usually learn early on that when the sample size n is large relative to the number of variables p, fitting a logistic model by the method of maximum likelihood produces estimates that are consistent and that there are well-known formulas that quantify the variability... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Pragya Sur, Emmanuel J. Candes Tags: PNAS Plus Source Type: research

Ingroup vigilance in collectivistic cultures [Psychological and Cognitive Sciences]
Collectivistic cultures have been characterized as having harmonious, cooperative ingroup relationships. However, we find evidence that people in collectivistic cultures are more vigilant toward ingroup members, mindful of their possible unethical intentions. Study 1 found that Chinese participants were more vigilant than Americans in within-group competitions, anticipating more unethical behaviors... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Shi S. Liu, Michael W. Morris, Thomas Talhelm, Qian Yang Tags: PNAS Plus Source Type: research

Crystal structure of jumping spider rhodopsin-1 as a light sensitive GPCR [Applied Biological Sciences]
Light-sensitive G protein-coupled receptors (GPCRs)—rhodopsins—absorb photons to isomerize their covalently bound retinal, triggering conformational changes that result in downstream signaling cascades. Monostable rhodopsins release retinal upon isomerization as opposed to the retinal in bistable rhodopsins that “reisomerize” upon absorption of a second photon. Understanding the mechanistic differences between these light-sensitive... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Niranȷan Varma, Eshita Mutt, Jonas Muhle, Valerie Panneels, Akihisa Terakita, Xavier Deupi, Przemyslaw Nogly, Gebhard F. X. Schertler, Elena Lesca Tags: PNAS Plus Source Type: research

Replication fork stalling elicits chromatin compaction for the stability of stalling replication forks [Biochemistry]
In this study, a cellular mechanism was uncovered that regulates chromatin structures to stabilize stalling forks. When... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Gang Feng, Yue Yuan, Zeyang Li, Lu Wang, Bo Zhang, Jiechen Luo, Jianguo Ji, Daochun Kong Tags: PNAS Plus Source Type: research

Selective targeting of PARP-2 inhibits androgen receptor signaling and prostate cancer growth through disruption of FOXA1 function [Biochemistry]
Androgen receptor (AR) is a ligand-activated transcription factor and a key driver of prostate cancer (PCa) growth and progression. Understanding the factors influencing AR-mediated gene expression provides new opportunities for therapeutic intervention. Poly(ADP-ribose) Polymerase (PARP) is a family of enzymes, which posttranslationally modify a range of proteins and regulate many... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Bin Gui, Fu Gui, Tomoaki Takai, Chao Feng, Xiao Bai, Ladan Fazli, Xuesen Dong, Shuai Liu, Xiaofeng Zhang, Wei Zhang, Adam S. Kibel, Li Jia Tags: PNAS Plus Source Type: research

Paf1C regulates RNA polymerase II progression by modulating elongation rate [Biochemistry]
Elongation factor Paf1C regulates several stages of the RNA polymerase II (Pol II) transcription cycle, although it is unclear how it modulates Pol II distribution and progression in mammalian cells. We found that conditional ablation of Paf1 resulted in the accumulation of unphosphorylated and Ser5 phosphorylated Pol II around promoter-proximal... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Liming Hou, Yating Wang, Yu Liu, Nan Zhang, Ilya Shamovsky, Evgeny Nudler, Bin Tian, Brian David Dynlacht Tags: PNAS Plus Source Type: research

Quantifying the transmission dynamics of MRSA in the community and healthcare settings in a low-prevalence country [Biophysics and Computational Biology]
Methicillin-resistant Staphylococcus aureus (MRSA) is a primarily nosocomial pathogen that, in recent years, has increasingly spread to the general population. The rising prevalence of MRSA in the community implies more frequent introductions in healthcare settings that could jeopardize the effectiveness of infection-control procedures. To investigate the epidemiological dynamics of MRSA... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Francesco Di Ruscio, Giorgio Guzzetta, Jorgen Vildershoȷ Bȷornholt, Truls Michael Leegaard, Aina Elisabeth Fossum Moen, Stefano Merler, Birgitte Freiesleben de Blasio Tags: PNAS Plus Source Type: research

Mapping the native organization of the yeast nuclear pore complex using nuclear radial intensity measurements [Cell Biology]
Selective transport across the nuclear envelope (NE) is mediated by the nuclear pore complex (NPC), a massive ∼100-MDa assembly composed of multiple copies of ∼30 nuclear pore proteins (Nups). Recent advances have shed light on the composition and structure of NPCs, but approaches that could map their organization in live... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Pascal Vallotton, Sasikumar Rajoo, Matthias Wojtynek, Evgeny Onischenko, Annemarie Kralt, Carina Patrizia Derrer, Karsten Weis Tags: PNAS Plus Source Type: research

Long noncoding RNA EMS connects c-Myc to cell cycle control and tumorigenesis [Cell Biology]
Deregulated expression of c-Myc is an important molecular hallmark of cancer. The oncogenic function of c-Myc has been largely attributed to its intrinsic nature as a master transcription factor. Here, we report the long noncoding RNA (lncRNA) E2F1 messenger RNA (mRNA) stabilizing factor (EMS) as a direct c-Myc transcriptional target.... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Chenfeng Wang, Yang Yang, Guang Zhang, Jingxin Li, Xianning Wu, Xiaoling Ma, Ge Shan, Yide Mei Tags: PNAS Plus Source Type: research

Long-term expansion and differentiation of adult murine epidermal stem cells in 3D organoid cultures [Cell Biology]
Mammalian epidermal stem cells maintain homeostasis of the skin epidermis and contribute to its regeneration throughout adult life. While 2D mouse epidermal stem cell cultures have been established decades ago, a long-term, feeder cell- and serum-free culture system recapitulating murine epidermal architecture has not been available. Here we describe an... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Kim E. Boonekamp, Kai Kretzschmar, Dominique J. Wiener, Priyanca Asra, Sepideh Derakhshan, Jens Puschhof, Carmen Lopez–Iglesias, Peter J. Peters, Onur Basak, Hans Clevers Tags: PNAS Plus Source Type: research

An unbiased approach elucidates variation in (S)-(+)-linalool, a context-specific mediator of a tri-trophic interaction in wild tobacco [Ecology]
Plant volatile organic compounds (VOCs) mediate many interactions, and the function of common VOCs is especially likely to depend on ecological context. We used a genetic mapping population of wild tobacco, Nicotiana attenuata, originating from a cross of 2 natural accessions from Arizona and Utah, separated by the Grand Canyon,... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Jun He, Richard A. Fandino, Rayko Halitschke, Katrin Luck, Tobias G. Kollner, Mark H. Murdock, Rishav Ray, Klaus Gase, Markus Knaden, Ian T. Baldwin, Meredith C. Schuman Tags: PNAS Plus Source Type: research

Unexpected host dependency of Antarctic Nanohaloarchaeota [Ecology]
We report cultivation of 2 strains of Antarctic Nanohaloarchaeota and show that they require the haloarchaeon Halorubrum lacusprofundi for growth. By performing growth using enrichments and fluorescence-activated cell sorting, we demonstrated successful cultivation... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Joshua N. Hamm, Susanne Erdmann, Emiley A. Eloe-Fadrosh, Allegra Angeloni, Ling Zhong, Christopher Brownlee, Timothy J. Williams, Kirston Barton, Shaun Carswell, Martin A. Smith, Sarah Brazendale, Alyce M. Hancock, Michelle A. Allen, Mark J. Raftery, Rica Tags: PNAS Plus Source Type: research

Ecomorphological diversification in squamates from conserved pattern of cranial integration [Evolution]
Factors intrinsic and extrinsic to organisms dictate the course of morphological evolution but are seldom considered together in comparative analyses. Among vertebrates, squamates (lizards and snakes) exhibit remarkable morphological and developmental variations that parallel their incredible ecological spectrum. However, this exceptional diversity also makes systematic quantification and analysis of their... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Akinobu Watanabe, Anne–Claire Fabre, Ryan N. Felice, Jessica A. Maisano, Johannes Muller, Anthony Herrel, Anȷali Goswami Tags: PNAS Plus Source Type: research

Predicting microbial growth in a mixed culture from growth curve data [Evolution]
Determining the fitness of specific microbial genotypes has extensive application in microbial genetics, evolution, and biotechnology. While estimates from growth curves are simple and allow high throughput, they are inaccurate and do not account for interactions between costs and benefits accruing over different parts of a growth cycle. For this... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Yoav Ram, Eynat Dellus-Gur, Maayan Bibi, Kedar Karkare, Uri Obolski, Marcus W. Feldman, Tim F. Cooper, Judith Berman, Lilach Hadany Tags: PNAS Plus Source Type: research

Cell-autonomous FLT3L shedding via ADAM10 mediates conventional dendritic cell development in mouse spleen [Immunology and Inflammation]
Conventional dendritic cells (cDCs) derive from bone marrow (BM) precursors that undergo cascades of developmental programs to terminally differentiate in peripheral tissues. Pre-cDC1s and pre-cDC2s commit in the BM to each differentiate into CD8α+/CD103+ cDC1s and CD11b+ cDC2s, respectively. Although both cDCs rely on the cytokine FLT3L during development, mechanisms... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Kohei Fujita, Svetoslav Chakarov, Tetsuro Kobayashi, Keiko Sakamoto, Benjamin Voisin, Kaibo Duan, Taneaki Nakagawa, Keisuke Horiuchi, Masayuki Amagai, Florent Ginhoux, Keisuke Nagao Tags: PNAS Plus Source Type: research

p110{gamma} deficiency protects against pancreatic carcinogenesis yet predisposes to diet-induced hepatotoxicity [Medical Sciences]
Pancreatic ductal adenocarcinoma (PDAC) is notorious for its poor survival and resistance to conventional therapies. PI3K signaling is implicated in both disease initiation and progression, and specific inhibitors of selected PI3K p110 isoforms for managing solid tumors are emerging. We demonstrate that increased activation of PI3K signals cooperates with oncogenic... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Carolina Torres, Georgina Mancinelli, Jose Cordoba-Chacon, Navin Viswakarma, Karla Castellanos, Sam Grimaldo, Sandeep Kumar, Daniel Principe, Matthew J. Dorman, Ronald McKinney, Emilio Hirsch, David Dawson, Hidayatullah G. Munshi, Ajay Rana, Paul J. Gripp Tags: PNAS Plus Source Type: research

Pandemic fluoroquinolone resistant Escherichia coli clone ST1193 emerged via simultaneous homologous recombinations in 11 gene loci [Microbiology]
Global growth in antibiotic resistance is a major social problem. A high level of resistance to fluoroquinolones requires the concurrent presence of at least 3 mutations in the target proteins—2 in DNA gyrase (GyrA) and 1 in topoisomerase IV (ParC), which occur in a stepwise manner. In the Escherichia coli... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Veronika Tchesnokova, Matthew Radey, Sujay Chattopadhyay, Lydia Larson, Jamie Lee Weaver, Dagmara Kisiela, Evgeni V. Sokurenko Tags: PNAS Plus Source Type: research

Insula serotonin 2A receptor binding and gene expression contribute to serotonin transporter polymorphism anxious phenotype in primates [Neuroscience]
Genetic variation in the serotonin transporter gene (SLC6A4) is associated with vulnerability to affective disorders and pharmacotherapy efficacy. We recently identified sequence polymorphisms in the common marmoset SLC6A4 repeat region (AC/C/G and CT/T/C) associated with individual differences in anxiety-like trait, gene expression, and response to antidepressants. The mechanisms underlying the... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Andrea M. Santangelo, Steve J. Sawiak, Tim Fryer, Young Hong, Yoshiro Shiba, Hannah F. Clarke, Patrick J. Riss, Valentina Ferrari, Roger Tait, John Suckling, Franklin I. Aigbirhio, Angela C. Roberts Tags: PNAS Plus Source Type: research

Sensorimotor brain dynamics reflect architectural affordances [Psychological and Cognitive Sciences]
Anticipating meaningful actions in the environment is an essential function of the brain. Such predictive mechanisms originate from the motor system and allow for inferring actions from environmental affordances, and the potential to act within a specific environment. Using architecture, we provide a unique perspective on the ongoing debate in... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Zakaria Djebbara, Lars Brorson Fich, Laura Petrini, Klaus Gramann Tags: PNAS Plus Source Type: research

Disentangling lattice and electronic contributions to the metal-insulator transition from bulk vs. layer confined RNiO3 [Applied Physical Sciences]
In complex oxide materials, changes in electronic properties are often associated with changes in crystal structure, raising the question of the relative roles of the electronic and lattice effects in driving the metal–insulator transition. This paper presents a combined theoretical and experimental analysis of the dependence of the metal–insulator transition... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Alexandru B. Georgescu, Oleg E. Peil, Ankit S. Disa, Antoine Georges, Andrew J. Millis Tags: Physical Sciences Source Type: research

De novo design of symmetric ferredoxins that shuttle electrons in vivo [Biochemistry]
A symmetric origin for bacterial ferredoxins was first proposed over 50 y ago, yet, to date, no functional symmetric molecule has been constructed. It is hypothesized that extant proteins have drifted from their symmetric roots via gene duplication followed by mutations. Phylogenetic analyses of extant ferredoxins support the independent evolution... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Andrew C. Mutter, Alexei M. Tyryshkin, Ian J. Campbell, Saroj Poudel, George N. Bennett, Jonathan J. Silberg, Vikas Nanda, Paul G. Falkowski Tags: Biological Sciences Source Type: research

Interspecies analysis of MYC targets identifies tRNA synthetases as mediators of growth and survival in MYC-overexpressing cells [Cell Biology]
Aberrant MYC oncogene activation is one of the most prevalent characteristics of cancer. By overlapping datasets of Drosophila genes that are insulin-responsive and also regulate nucleolus size, we enriched for Myc target genes required for cellular biosynthesis. Among these, we identified the aminoacyl tRNA synthetases (aaRSs) as essential mediators of... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Jonathan Zirin, Xiaochun Ni, Laura M. Sack, Donghui Yang-Zhou, Yanhui Hu, Roderick Brathwaite, Martha L. Bulyk, Stephen J. Elledge, Norbert Perrimon Tags: Biological Sciences Source Type: research

Engineering opposite electronic polarization of singlet and triplet states increases the yield of high-energy photoproducts [Chemistry]
Efficient photosynthetic energy conversion requires quantitative, light-driven formation of high-energy, charge-separated states. However, energies of high-lying excited states are rarely extracted, in part because the congested density of states in the excited-state manifold leads to rapid deactivation. Conventional photosystem designs promote electron transfer (ET) by polarizing excited donor electron density... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Nicholas F. Polizzi, Ting Jiang, David N. Beratan, Michael J. Therien Tags: Physical Sciences Source Type: research

Optimal control strategies for inhibition of protein aggregation [Chemistry]
Protein aggregation has been implicated in many medical disorders, including Alzheimer’s and Parkinson’s diseases. Potential therapeutic strategies for these diseases propose the use of drugs to inhibit specific molecular events during the aggregation process. However, viable treatment protocols require balancing the efficacy of the drug with its toxicity, while accounting... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Thomas C. T. Michaels, Christoph A. Weber, L. Mahadevan Tags: Biological Sciences Source Type: research

Diversification of small RNA amplification mechanisms for targeting transposon-related sequences in ciliates [Developmental Biology]
The silencing of repetitive transposable elements (TEs) is ensured by signal amplification of the initial small RNA trigger, which occurs at distinct steps of TE silencing in different eukaryotes. How such a variety of secondary small RNA biogenesis mechanisms has evolved has not been thoroughly elucidated. Ciliated protozoa perform small... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Masatoshi Mutazono, Tomoko Noto, Kazufumi Mochizuki Tags: Biological Sciences Source Type: research

Direct detection of atmospheric atomic bromine leading to mercury and ozone depletion [Earth, Atmospheric, and Planetary Sciences]
Bromine atoms play a central role in atmospheric reactive halogen chemistry, depleting ozone and elemental mercury, thereby enhancing deposition of toxic mercury, particularly in the Arctic near-surface troposphere. However, direct bromine atom measurements have been missing to date, due to the lack of analytical capability with sufficient sensitivity for ambient... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Siyuan Wang, Stephen M. McNamara, Christopher W. Moore, Daniel Obrist, Alexandra Steffen, Paul B. Shepson, Ralf M. Staebler, Angela R. W. Raso, Kerri A. Pratt Tags: Physical Sciences Source Type: research

Bovine tuberculosis disturbs parasite functional trait composition in African buffalo [Ecology]
Novel parasites can have wide-ranging impacts, not only on host populations, but also on the resident parasite community. Historically, impacts of novel parasites have been assessed by examining pairwise interactions between parasite species. However, parasite communities are complex networks of interacting species. Here we used multivariate taxonomic and trait-based approaches... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Brianna R. Beechler, Kate S. Boersma, Peter E. Buss, Courtney A. C. Coon, Erin E. Gorsich, Brian S. Henrichs, Adam M. Siepielski, Johannie M. Spaan, Robert S. Spaan, Vanessa O. Ezenwa, Anna E. Jolles Tags: Biological Sciences Source Type: research

Wind farm power optimization through wake steering [Engineering]
Global power production increasingly relies on wind farms to supply low-carbon energy. The recent Intergovernmental Panel on Climate Change (IPCC) Special Report predicted that renewable energy production must leap from 20% of the global energy mix in 2018 to 67% by 2050 to keep global temperatures from rising 1.5°C above... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Michael F. Howland, Sanjiva K. Lele, John O. Dabiri Tags: Physical Sciences Source Type: research

A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic [Environmental Sciences]
Following over 3 decades of gradual but uneven increases in sea ice coverage, the yearly average Antarctic sea ice extents reached a record high of 12.8 × 106 km2 in 2014, followed by a decline so precipitous that they reached their lowest value in the 40-y 1979–2018 satellite multichannel passive-microwave... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Claire L. Parkinson Tags: Inaugural Articles Physical Sciences Source Type: research

News Feature: Do hosts and their microbes evolve as a unit? [Evolution]
A group of evolutionary biologists sees evidence for a hologenome whereas others dismiss it entirely. One thing’s certain: the debate remains heated. Tilapias like their baths balmy. These tropical fish are happiest in warm pools. But they can be made to adapt to tanks as cold as 12 °C, where... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Jyoti Madhusoodanan Tags: News Features, Front Matter Source Type: research

Contemporary loss of migration in monarch butterflies [Evolution]
The annual migration of the monarch butterfly Danaus plexippus is in peril. In an effort to aid population recovery, monarch enthusiasts across North America participate in a variety of conservation efforts, including captive rearing and release of monarch butterflies throughout the summer and autumn. However, the impact of captive breeding... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Ayşe Tenger–Trolander, Wei Lu, Michelle Noyes, Marcus R. Kronforst Tags: Biological Sciences Source Type: research

Evolution of facial muscle anatomy in dogs [Evolution]
Domestication shaped wolves into dogs and transformed both their behavior and their anatomy. Here we show that, in only 33,000 y, domestication transformed the facial muscle anatomy of dogs specifically for facial communication with humans. Based on dissections of dog and wolf heads, we show that the levator anguli oculi... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Juliane Kaminski, Bridget M. Waller, Rui Diogo, Adam Hartstone-Rose, Anne M. Burrows Tags: Biological Sciences Source Type: research

Female bed bugs (Cimex lectularius L) anticipate the immunological consequences of traumatic insemination via feeding cues [Evolution]
In this study we show that female insects (bed bugs) up-regulate immune function in their copulatory organ... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Michael T. Siva-Jothy, Weihao Zhong, Richard Naylor, Louise Heaton, William Hentley, Ewan Harney Tags: Biological Sciences Source Type: research

Two modes of cis-activation of switch transcription by the IgH superenhancer [Immunology and Inflammation]
B cell isotype switching plays an important role in modulating adaptive immune responses. It occurs in response to specific signals that often induce different isotype (I) promoters driving transcription of switch regions, located upstream of the Ig heavy chain (IgH) constant genes. The transcribed switch regions can recombine, leading to... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Joana M. Santos, Fatima–Zohra Braikia, Chloe Oudinet, Audrey Dauba, Ahmed Amine Khamlichi Tags: Biological Sciences Source Type: research

Characterizing round spheres using half-geodesics [Mathematics]
A half-geodesic is a closed geodesic realizing the distance between any pair of its points. All geodesics in a round sphere are half-geodesics. Conversely, this paper establishes that Riemannian spheres with all geodesics closed and sufficiently many half-geodesics are round. (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Ian M. Adelstein, Benjamin Schmidt Tags: Physical Sciences Source Type: research

Epistasis between antibiotic tolerance, persistence, and resistance mutations [Microbiology]
Understanding the evolution of microorganisms under antibiotic treatments is a burning issue. Typically, several resistance mutations can accumulate under antibiotic treatment, and the way in which resistance mutations interact, i.e., epistasis, has been extensively studied. We recently showed that the evolution of antibiotic resistance in Escherichia coli is facilitated by... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Irit Levin-Reisman, Asher Brauner, Irine Ronin, Nathalie Q. Balaban Tags: Biological Sciences Source Type: research

AAV2/9-mediated overexpression of MIF inhibits SOD1 misfolding, delays disease onset, and extends survival in mouse models of ALS [Neuroscience]
Mutations in superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by the loss of upper and lower motor neurons. Transgenic mice that overexpress mutant SOD1 develop paralysis and accumulate misfolded SOD1 onto the cytoplasmic faces of intracellular organelles, including mitochondria and endoplasmic reticulum (ER). Recently, macrophage... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Marcel F. Leyton-Jaimes, Joy Kahn, Adrian Israelson Tags: Biological Sciences Source Type: research

Strong quantum fluctuations in a quantum spin liquid candidate with a Co-based triangular lattice [Physics]
Currently under active study in condensed matter physics, both theoretically and experimentally, are quantum spin liquid (QSL) states, in which no long-range magnetic ordering appears at low temperatures due to strong quantum fluctuations of the magnetic moments. The existing QSL candidates all have their intrinsic disadvantages, however, and solid evidence... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Ruidan Zhong, Shu Guo, Guangyong Xu, Zhijun Xu, Robert J. Cava Tags: Physical Sciences Source Type: research

Visualization of an axion insulating state at the transition between 2 chiral quantum anomalous Hall states [Physics]
Quantum-relativistic materials often host electronic phenomena with exotic spatial distributions. In particular, quantum anomalous Hall (QAH) insulators feature topological boundary currents whose chirality is determined by the magnetization orientation. However, understanding the microscopic nature of edge vs. bulk currents has remained a challenge due to the emergence of multidomain states... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Monica Allen, Yongtao Cui, Eric Yue Ma, Masataka Mogi, Minoru Kawamura, Ion Cosma Fulga, David Goldhaber-Gordon, Yoshinori Tokura, Zhi-Xun Shen Tags: Physical Sciences Source Type: research

Neural adaptation to faces reveals racial outgroup homogeneity effects in early perception [Psychological and Cognitive Sciences]
A hallmark of intergroup biases is the tendency to individuate members of one’s own group but process members of other groups categorically. While the consequences of these biases for stereotyping and discrimination are well-documented, their early perceptual underpinnings remain less understood. Here, we investigated the neural mechanisms of this effect... (Source: Proceedings of the National Academy of Sciences)
Source: Proceedings of the National Academy of Sciences - July 16, 2019 Category: Science Authors: Brent L. Hughes, Nicholas P. Camp, Jesse Gomez, Vaidehi S. Natu, Kalanit Grill-Spector, Jennifer L. Eberhardt Tags: Social Sciences Source Type: research