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High-energy physics: Proton smasher spots rare particle decays
The extremely rare decays of particles known as neutral B mesons have been observed at CERN's Large Hadron Collider. The result may be a glimpse of physics beyond that of the standard model of particle physics.
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Molecular biology: Splicing does the two-step
An intricate recursive RNA splicing mechanism that removes especially long introns (non-coding sequences) from genes has been found to be evolutionarily conserved and more prevalent than previously thought.
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Neurotransmitter and psychostimulant recognition by the dopamine transporter
Here the X-ray crystal structures of the Drosophila dopamine transporter bound to dopamine, D-amphetamine, methamphetamine and cocaine are solved; these structures show how a neurotransmitter, small molecule stimulants and cocaine bind to a biogenic amine transporter, and are examples of how the ligand binding site of a neurotransmitter transporter can remodel itself to accommodate structurally unrelated small molecules that are different in shape, size and polarity or charge.
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PPAR-α and glucocorticoid receptor synergize to promote erythroid progenitor self-renewal
Some types of anaemia do not respond to erythropoietin (Epo) treatment because patients do not have sufficient numbers of Epo-sensitive erythroid precursor cells; here, two agonists of PPAR-α are found to synergize with glucocorticoid treatment to promote early erythroid progenitor self-renewal, increasing the production of mature red blood cells in both human and mouse cultures and alleviating anaemia in mouse models.
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Mechanical induction of the tumorigenic β-catenin pathway by tumour growth pressure
Magnetically induced mechanical strain mimicking the pressure exerted by a growing tumour in the mouse colon is shown to activate the tumorigenic β-catenin pathway in healthy epithelia, suggesting an alternative pathway, mechanotransductive in nature, in the propagation of tumorigenesis and growth from tumour to healthy tissue.
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MYC regulates the core pre-mRNA splicing machinery as an essential step in lymphomagenesis
The critical effectors of MYC overexpression during lymphomagenesis in transgenic mice are defined.
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Cytosolic extensions directly regulate a rhomboid protease by modulating substrate gating
Calcium potently stimulates proteolysis by endogenous rhomboid-4, an intramembrane protease that contains a cytoplasmic calcium-binding EF-hand domain.
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Melanoma-intrinsic β-catenin signalling prevents anti-tumour immunity
Only a subset of patients with melanoma responds to new immunotherapeutic therapies; here, β-catenin signalling is identified as an important pathway that confers resistance to this type of approach, with implications for future treatment strategies.
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Recursive splicing in long vertebrate genes
Highly conserved recursive splice sites are identified in vertebrates, particularly within long genes encoding proteins that are involved in neuronal development; analysis of the splicing mechanism reveals that such recursive splicing sites can be used to dictate different mRNA isoforms.
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Observation of the rare Bsͦ
→µ+µ− decay from the combined analysis of CMS and LHCb data OPEN
Combined analysis of proton-proton collision data from the Large Hadron Collider at CERN by the CMS and LHCb collaborations leads to the observation of the extremely rare decay of the strange B meson into muons; the result is compatible with the standard model of particle physics, and does not show any signs of new physics, such as supersymmetry.
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Genome-wide identification of zero nucleotide recursive splicing in Drosophila
In flies, some introns contain internal splice sites that cause ‘recursive splicing’, a multi-step removal of a single intron; this study demonstrates that the scope of this regulatory mechanism is much more extensive in flies than had been appreciated, and provides details about the recursive splicing process.
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Genetic diversity and evolutionary dynamics of Ebola virus in Sierra Leone
The genome sequences of 175 Ebola virus from five districts in Sierra Leone, collected during September–November 2014, show that the rate of virus evolution seems to be similar to that observed during previous outbreaks and that the genetic diversity of the virus has increased substantially, with the emergence of several novel lineages.
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Complex archaea that bridge the gap between prokaryotes and eukaryotes
This study identifies a clade of archaea that is the immediate sister group of eukaryotes in phylogenetic analyses, and that also has a repertoire of proteins otherwise characteristic of eukaryotes—proteins that would have provided the first eukaryotes with a ‘starter kit’ for the genomic and cellular complexity characteristic of the eukaryotic cell.
Anja Spang, Jimmy H. Saw, Steffen L. Jørgensen et al. |
Neurons for hunger and thirst transmit a negative-valence teaching signal
Cell-type-specific electrical activity manipulations and deep-brain imaging in mice of neuronal populations associated with homeostasis of nutrient or fluid intake reveals that learning is conditioned by a negative-valence signal from the hunger-mediating AGRP neurons and also from the thirst-mediating neurons in the subfornical organ.
J. Nicholas Betley, Shengjin Xu, Zhen Fang Huang Cao et al. |
Neural dynamics for landmark orientation and angular path integration
Calcium imaging of the brain of tethered flies walking in a virtual reality arena showed that a population of neurons with dendrites that tile the ‘ellipsoid body’ use information from visual landmarks and the fly's own rotation to compute heading; this suggests insects possess neurons with similarities to ‘head direction cells’ known to contribute to spatial navigation in mammalian brains.
Johannes D. Seelig, Vivek Jayaraman |
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Strangulation as the primary mechanism for shutting down star formation in galaxies
An analysis of the stellar metallicity of local galaxies reveals that strangulation (halting of cold gas supply) rather than sudden removal of gas (through outflows or stripping) is the primary mechanism responsible for the quenching of star formation.
Y. Peng, R. Maiolino, R. Cochrane |
Electron pairing without superconductivity
Evidence is presented for electron pairing in strontium titanate far above the superconducting transition temperature; such pairs are thought to be the long-sought pre-formed pairs that condense at lower temperatures to give rise to the unconventional superconducting state in this system.
Guanglei Cheng, Michelle Tomczyk, Shicheng Lu et al. |
Quantum coherent optical phase modulation in an ultrafast transmission electron microscope
The coherent manipulation of electron quantum states using light, commonly employed in atoms and molecules, is extended to the case of free electron beams using ultrafast transmission electron microscopy; this approach may enable a range of applications in ultrafast electron imaging and spectroscopy down to attosecond precision.
Armin Feist, Katharina E. Echternkamp, Jakob Schauss et al. |
Global carbon export from the terrestrial biosphere controlled by erosion
Particulate organic carbon export from the terrestrial biosphere is primarily controlled by physical erosion, and tectonic and climatic forcing of physical erosion may favour biospheric particulate organic carbon sequestration over silicate weathering as a long-term atmospheric carbon dioxide sink.
Valier Galy, Bernhard Peucker-Ehrenbrink, Timothy Eglinton |
Multi-omics of permafrost, active layer and thermokarst bog soil microbiomes
A multi-omics approach, integrating metagenomics, metatranscriptomics and metaproteomics, determines the phylogenetic composition of the microbial community and assesses its functional potential and activity along a thaw transition from intact permafrost to thermokast bog.
Jenni Hultman, Mark P. Waldrop, Rachel Mackelprang et al. |
Pathogen-secreted proteases activate a novel plant immune pathway
In Arabidopsis thaliana, pathogen-secreted proteases trigger a previously unknown defence response involving heterotrimeric G-protein complexes upstream of a mitogen-activated protein kinase cascade.
Zhenyu Cheng, Jian-Feng Li, Yajie Niu et al. |
YAP is essential for tissue tension to ensure vertebrate 3D body shape
D’Arcy Thompson predicted a century ago that animal body shape is conditioned by gravity, but there has been no animal model to study how cellular forces are coordinated to generate body shapes that withstand gravity; the hirame medaka fish mutant, with pronounced body flattening, reveals how the hirame/YAP gene controls gravity-resisting cellular forces to produce complex 3D organs and body shapes.
Sean Porazinski, Huijia Wang, Yoichi Asaoka et al. |
Clinical improvement in psoriasis with specific targeting of interleukin-23
A proof-of-concept phase I clinical trial demonstrates that targeting interleukin (IL)-23 with an antibody that binds to the p19 subunit leads to clinical improvement of disease in patients with moderate to severe psoriasis.
Tamara Kopp, Elisabeth Riedl, Christine Bangert et al. |
Nuclear architecture dictates HIV-1 integration site selection
HIV-1 integration into the host cell genome occurs in the outer shell of the nucleus in close correspondence with the nuclear pore, in which a series of cellular genes are preferentially targeted by the virus.
Bruna Marini, Attila Kertesz-Farkas, Hashim Ali et al. |
The Xist lncRNA interacts directly with SHARP to silence transcription through HDAC3
The mechanisms by which Xist, a long non-coding RNA, silences one X chromosome in female mammals are unknown; here a mass spectrometry-based approach is developed to identify several proteins that interact directly with Xist, including the transcriptional repressor SHARP that is required for transcriptional silencing through the histone deacetylase HDAC3.
Colleen A. McHugh, Chun-Kan Chen, Amy Chow et al. |
Horizontal membrane-intrinsic α-helices in the stator a-subunit of an F-type ATP synthase
Electron cryomicroscopy of a complete mitochondrial ATP-synthase dimer reveals the elusive structure of the essential a-subunit.
Matteo Allegretti, Niklas Klusch, Deryck J. Mills et al. |
Electron cryomicroscopy observation of rotational states in a eukaryotic V-ATPase
Electron cryomicroscopy shows structures of three distinct rotational states of the V-ATPase from Saccharomyces cerevisiae.
Jianhua Zhao, Samir Benlekbir, John L. Rubinstein |
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