| | Neuroscience: Dragonflies predict and plan their hunts
An analysis reveals that the dragonfly's impressive ability to catch its prey arises from internal calculations about its own movements and those of its target — the first example of such predictions in invertebrates.
| Biophysics: Enzymes surf the heat wave
Molecular diffusion of some enzymes is enhanced when they catalyse reactions, but the reason for this was obscure. Dissipation of heat generated by catalysis through the protein is now thought to propel the molecules.
| Cell cycle: It takes three to find the exit
Mitotic cell division separates chromosome pairs into two genetically identical daughter cells. A study in fission yeast reveals that this separation is guided by the sequential activation of three phosphatase enzymes.
| Ocean biogeochemistry: Carbon at the coastal interface
The extent to which coastal-ocean regions act as a sink for carbon dioxide has been enigmatic. An estimate based on more than 3 million observations suggests a smaller sink than was thought, concentrated at high latitudes.
| Microbiology: Diverted on the way to memory
The finding that protein A of Staphylococcus aureus diverts the immune response so that it ineffectively responds to other structures from the bacterium explains the failure of ongoing attempts to develop working S. aureus vaccines.
| Internal models direct dragonfly interception steering
This study tracks dragonfly head and body movements during high-velocity and high-precision prey-capture flights, and shows that the dragonfly uses predictive internal models and reactive control to build an interception trajectory that complies with biomechanical constraints.
| Genome-scale transcriptional activation by an engineered CRISPR-Cas9 complex
The CRISPR-Cas9 system, a powerful tool for genome editing, has been engineered to specifically and potently activate endogenous gene transcription on a genome-wide scale and applied to a large-scale gain-of-function screen for studying melanoma drug resistance.
| Exome sequencing identifies rare LDLR and APOA5 alleles conferring risk for myocardial infarction
Exome sequence analysis of nearly 10,000 people was carried out to identify alleles associated with early-onset myocardial infarction; mutations in low-density lipoprotein receptor (LDLR) or apolipoprotein A-V (APOA5) were associated with disease risk, identifying the key roles of low-density lipoprotein cholesterol and metabolism of triglyceride-rich lipoproteins.
| Role of TP53 mutations in the origin and evolution of therapy-related acute myeloid leukaemia
Somatic TP53 mutations are highly prevalent in therapy-related acute myeloid leukaemia and myelodysplastic syndrome, which arise as complications of cytotoxic chemotherapy or radiotherapy; although it was believed that these TP53 mutations are directly induced by cytotoxic therapy, new data indicate that they predate cytotoxic therapy and that haematopoietic progenitors harbouring these pre-existing mutations may selectively expand after exposure to chemotherapy or radiotherapy.
| Intracellular α-ketoglutarate maintains the pluripotency of embryonic stem cells
If deprived of exogenous glutamine, naive mouse embryonic stem cells are shown to be capable of generating the amino acid from other sources to enable their proliferation; the stem cells use glutamine and glucose catabolism to maintain a high level of intracellular α-ketoglutarate and promote demethylation of chromatin and ensure sufficient expression of pluripotency-associated genes.
| Spatiotemporal transcriptomics reveals the evolutionary history of the endoderm germ layer
Studies of gene-expression levels in embryos of Caenorhabditis elegans and of other phyla reveal the timing and location of expression of all genes and support a model in which the endoderm program dates back to the origin of multicellularity while the ectoderm originated as a secondary germ layer freed from ancestral feeding functions.
| Evolution of the new vertebrate head by co-option of an ancient chordate skeletal tissue
A tissue with many of the defining features of vertebrate cellular cartilage is shown to form transiently in larvae of the invertebrate chordate amphioxus, indicating that the origin of the vertebrate head skeleton depended not on evolution of a new skeletal tissue, as is commonly thought, but on the spread of this tissue throughout the head.
| A PP1–PP2A phosphatase relay controls mitotic progression
The activation and coordination of phosphatase activity is important during mitotic exit; here, a mitotic phosphatase relay is described in fission yeast between the two major phosphatases, PP1 and PP2A, a mode of regulation that may be a feature of signalling networks across eukaryotes.
| The heat released during catalytic turnover enhances the diffusion of an enzyme
It has been traditionally assumed that the heat released during a single enzymatic catalytic event does not perturb the enzyme in any way; however, here single-molecule fluorescence correlation spectroscopy is used to show that, for enzymes that catalyse chemical reactions with large reaction enthalpies, the heat released at the protein's active site during catalysis transiently displaces the protein's centre-of-mass, essentially giving rise to a recoil effect that propels the enzyme.
| Higher-than-predicted saltation threshold wind speeds on Titan
Wind tunnel experiments designed to simulate the conditions on Saturn's moon Titan yield threshold wind speeds for particle saltation higher than those predicted by models derived from simulations of terrestrial-planet conditions; the results can be reconciled by modifying the models to take into account the low ratio of particle density to fluid density on Titan.
| | | Brief Communications Arising | | | | Catalytic enantioselective synthesis of quaternary carbon stereocentres
Carbon atoms to which four distinct carbon substituents are attached — quaternary carbon stereocentres — are common features of molecules found in nature; in this Review, the authors discuss catalytic enantioselective reactions that have been developed during the past decade for synthesizing organic molecules containing such carbon atoms.
Kyle W. Quasdorf, Larry E. Overman | | Divergent reprogramming routes lead to alternative stem-cell states
The forced expression of key transcription factors can induce somatic cells to acquire pluripotency characteristics; here high levels of reprogramming factors are used to induce mouse embryonic fibroblasts to a stable alternative pluripotent state with low intercellular adhesion.
Peter D. Tonge, Andrew J. Corso, Claudio Monetti et al. | Genome-wide characterization of the routes to pluripotency
This study presents an extensive molecular characterization of the reprograming process by analysis of transcriptomic, epigenomic and proteomic data sets describing the routes to pluripotency; it finds distinct routes towards two stable pluripotent states characterized by distinct epigenetic events.
Samer M. I. Hussein, Mira C. Puri, Peter D. Tonge et al. | X-ray structure of a calcium-activated TMEM16 lipid scramblase
The authors describe the structure of a Ca2+-activated lipid scramblase which catalyses the passive movement of lipids between the two leaflets of a lipid bilayer; the structure reveals the location of a regulatory calcium-binding site embedded within the membrane and the presence of a hydrophilic membrane-traversing cavity that is exposed to the lipid bilayer, where catalysis is likely to occur.
Janine D. Brunner, Novandy K. Lim, Stephan Schenck et al. | Structure and insights into the function of a Ca2+-activated Cl− channel
The X-ray crystal structure of a eukaryotic Ca2+-activated chloride channel, BEST1, and its function in liposomes are described; the structure shows that Ca2+ binds to the cytosolic region of this pentameric channel and reveals that the pore is approximately 95 Å long with at least 15 distinct anion-binding sites.
Veronica Kane Dickson, Leanne Pedi, Stephen B. Long | | Cell differentiation and germ–soma separation in Ediacaran animal embryo-like fossils
Spheroidal microfossils from the Ediacaran Doushantuo phosphorites show clear signs of cell differentiation, programmed cell death, and separation between soma and germline, and seem to represent a hitherto unknown experiment in multicellular life like nothing on Earth today.
Lei Chen, Shuhai Xiao, Ke Pang et al. | Dietary modulation of the microbiome affects autoinflammatory disease
Pstpip2-mutant mice fed a high-fat diet are protected against inflammatory bone disease and bone erosion; this protection is associated with reductions in intestinal Prevotella levels and pro-IL-1β expression, and is dependent on the deletion of both caspases 1 and 8.
John R. Lukens, Prajwal Gurung, Peter Vogel et al. | H2D+ observations give an age of at least one million years for a cloud core forming Sun-like stars
Observations of emission and absorption lines of the deuterated trihydrogen cation (H2D+) from a dense interstellar cloud core, combined with chemical modelling, reveal that the core needed at least one million years to form Sun-like stars.
Sandra Brünken, Olli Sipilä, Edward T. Chambers et al. | Ultrasensitive mechanical crack-based sensor inspired by the spider sensory system
A mechanical crack-based sensor inspired by the mechanism spiders use to sense minute variations in stress offers ultrahigh sensitivity to pressure and vibration and can easily be mounted on human skin for the purposes of speech recognition and the monitoring of physiological signals.
Daeshik Kang, Peter V. Pikhitsa, Yong Whan Choi et al. | Proton transport through one-atom-thick crystals
Measurements show that monolayers of graphene and hexagonal boron nitride are unexpectedly highly permeable to thermal protons and that their conductivity rapidly increases with temperature, but that no proton transport is detected for few-layer crystals.
S. Hu, M. Lozada-Hidalgo, F. C. Wang et al. | Formation and properties of ice XVI obtained by emptying a type sII clathrate hydrate
Gas hydrates are ice-like solids that have guest species encaged within a crystalline water framework, making the empty hydrate a natural — though long assumed to be inaccessible — point of reference; it is now shown that several days of continuous vacuum pumping removes all guests from neon hydrate, and the physical properties of the empty hydrate have been determined.
Andrzej Falenty, Thomas C. Hansen, Werner F. Kuhs | Isotopic constraints on marine and terrestrial N2O emissions during the last deglaciation
Analysis of air trapped in Antarctic ice between 16,000 and 10,000 years before present yields nitrous oxide concentrations and isotopic data showing that the relative contributions from marine and terrestrial sources to nitrous oxide emission changes were equal during that period, but that terrestrial emissions dominated on centennial timescales.
Adrian Schilt, Edward J. Brook, Thomas K. Bauska et al. | An evolutionary arms race between KRAB zinc-finger genes ZNF91/93 and SVA/L1 retrotransposons
The authors show that two primate-specific genes encoding KRAB domain containing zinc finger proteins, ZNF91 and ZNF93, have evolved during the last 25 million years to repress retrotransposon families that emerged during this time period; according to the new data KZNF gene expansion limits the activity of newly emerged retrotransposons, which subsequently mutate to evade repression.
Frank M. J. Jacobs, David Greenberg, Ngan Nguyen et al. | Structural and mechanistic insights into the bacterial amyloid secretion channel CsgG
CsgG and CgsE form an encaging translocon for selective, iterative diffusion of curli subunits across the non-energized bacterial outer membrane.
Parveen Goyal, Petya V. Krasteva, Nani Van Gerven et al. | Loss of signalling via Gα13 in germinal centre B-cell-derived lymphoma
Inactivation of the S1PR2–Gα13–ARHGEF1 signalling pathway in mice allows Akt activation and promotes dissemination of germinal centre B cells, consistent with a role of function-disrupting mutations in the systemic dissemination of diffuse large B-cell lymphoma.
Jagan R. Muppidi, Roland Schmitz, Jesse A. Green et al. | MapZ marks the division sites and positions FtsZ rings in Streptococcus pneumoniae
A new mechanism is identified for correct placement of the division machinery in Streptococcus pneumoniae that relies on the novel factor MapZ to form ring structures at the cell equator; these structures move apart as the cell elongates, acting as permanent markers of division sites.
Aurore Fleurie, Christian Lesterlin, Sylvie Manuse et al. | Programmable RNA recognition and cleavage by CRISPR/Cas9
In the presence of a short DNA oligonucleotide containing a protospacer adjacent motif, a guide-RNA-programmed Cas9 is able to specifically bind and/or cleave single-stranded RNA—this system can be used to isolate specific endogenous RNA transcripts from a cell lysate without any tag or modification.
Mitchell R. O'Connell, Benjamin L. Oakes, Samuel H. Sternberg et al. | Tyrosine phosphorylation of histone H2A by CK2 regulates transcriptional elongation
A conserved tyrosine residue, Tyr 57, of histone H2A is phosphorylated by an unsuspected tyrosine kinase activity of casein kinase 2, influencing a series of histone marks associated with active transcription and regulating transcription elongation.
Harihar Basnet, Xue B. Su, Yuliang Tan et al. | Regulation of RNA polymerase II activation by histone acetylation in single living cells
The interplay of histone acetylation and RNA polymerase II activity is investigated using fluorescence microscopy; acetylation of H3 at Lys 27 enhances the recruitment of a transcriptional activator and accelerates the transition of RNA polymerase II from initiation to elongation, thus indicating that histone acetylation has a causal effect on two distinct steps in transcription activation.
Timothy J. Stasevich, Yoko Hayashi-Takanaka, Yuko Sato et al. | | | | |
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