Proceedings of the Natural Academy of Sciences

Proceedings of the National Academy of Sciences RSS feed -- current issue
  • Antibody persistence and T-cell balance [Medical Sciences]
    [Nov 2014]

    The quest for a prophylactic AIDS vaccine is ongoing, but it is now clear that the successful vaccine must elicit protective antibody responses. Accordingly, intense efforts are underway to identify immunogens that elicit these responses. Regardless of the mechanism of antibody-mediated protection, be it neutralization, Fc-mediated effector function, or both,...
    Categories: Journal Articles
  • Long-term pesticide applications and soil erosion [Agricultural Sciences]
    [Nov 2014]

    Agricultural pesticide use has increased worldwide during the last several decades, but the long-term fate, storage, and transfer dynamics of pesticides in a changing environment are poorly understood. Many pesticides have been progressively banned, but in numerous cases, these molecules are stable and may persist in soils, sediments, and ice....
    Categories: Journal Articles
  • OsABCC1 reduces As accumulation in rice grain [Agricultural Sciences]
    [Nov 2014]

    Arsenic (As) is a chronic poison that causes severe skin lesions and cancer. Rice (Oryza sativa L.) is a major dietary source of As; therefore, reducing As accumulation in the rice grain and thereby diminishing the amount of As that enters the food chain is of critical importance. Here, we...
    Categories: Journal Articles
  • Bioinspired micrograting arrays [Applied Biological Sciences]
    [Nov 2014]

    Recently, diffraction elements that reverse the color sequence normally observed in planar diffraction gratings have been found in the wing scales of the butterfly Pierella luna. Here, we describe the creation of an artificial photonic material mimicking this reverse color-order diffraction effect. The bioinspired system consists of ordered arrays of...
    Categories: Journal Articles
  • CpGV resistance in codling moth depends on viral pe38 [Applied Biological Sciences]
    [Nov 2014]

    The baculovirus Cydia pomonella granulovirus (CpGV) is widely applied as a biocontrol agent of codling moth. After field resistance of codling moth populations had been observed against the commercially used Mexican (M) isolate of CpGV, infection experiments of larvae of the resistant codling moth strain CpRR1 showed that several other...
    Categories: Journal Articles
  • Engineering epoxide hydrolase for bulky substrates [Applied Biological Sciences]
    [Nov 2014]

    Optically pure epoxides are essential chiral precursors for the production of (S)-propranolol, (S)-alprenolol, and other β-adrenergic receptor blocking drugs. Although the enzymatic production of these bulky epoxides has proven difficult, here we report a method to effectively improve the activity of BmEH, an epoxide hydrolase from Bacillus megaterium ECU1001 toward...
    Categories: Journal Articles
  • Argonaute-1 binds transcriptional enhancers [Biochemistry]
    [Nov 2014]

    The roles of Argonaute proteins in cytoplasmic microRNA and RNAi pathways are well established. However, their implication in small RNA-mediated transcriptional gene silencing in the mammalian cell nucleus is less understood. We have recently shown that intronic siRNAs cause chromatin modifications that inhibit RNA polymerase II elongation and modulate alternative...
    Categories: Journal Articles
  • Fam20B activates proteoglycan synthesis [Biochemistry]
    [Nov 2014]

    Most eukaryotic cells elaborate several proteoglycans critical for transmitting biochemical signals into and between cells. However, the regulation of proteoglycan biosynthesis is not completely understood. We show that the atypical secretory kinase family with sequence similarity 20, member B (Fam20B) phosphorylates the initiating xylose residue in the proteoglycan tetrasaccharide linkage...
    Categories: Journal Articles
  • Proteolytic control of NOGO-A by praja2 [Biochemistry]
    [Nov 2014]

    Protein kinase A (PKA) controls major aspects of neurite outgrowth and morphogenesis and plays an essential role in synaptic plasticity and memory. However, the molecular mechanism(s) of PKA action on neurite sprouting and activity are still unknown. Here, we report that in response to neurotrophin or cAMP stimulation the RING...
    Categories: Journal Articles
  • Supercomplexes are not catalytically relevant [Biochemistry]
    [Nov 2014]

    In mitochondria, four respiratory-chain complexes drive oxidative phosphorylation by sustaining a proton-motive force across the inner membrane that is used to synthesize ATP. The question of how the densely packed proteins of the inner membrane are organized to optimize structure and function has returned to prominence with the characterization of...
    Categories: Journal Articles
  • Ligand for leukocyte tyrosine kinase [Biochemistry]
    [Nov 2014]

    There are many transmembrane receptor-like proteins whose ligands have not been identified. A strategy for finding ligands when little is known about their tissue source is to screen each extracellular protein individually expressed in an array format by using a sensitive functional readout. Taking this approach, we have screened a...
    Categories: Journal Articles
  • An N-terminal scaffold stabilizes S. mutans P1 [Biochemistry]
    [Nov 2014]

    The cariogenic bacterium Streptococcus mutans uses adhesin P1 to adhere to tooth surfaces, extracellular matrix components, and other bacteria. A composite model of P1 based on partial crystal structures revealed an unusual complex architecture in which the protein forms an elongated hybrid alpha/polyproline type II helical stalk by folding back...
    Categories: Journal Articles
  • Volta phase plate for TEM [Biophysics and Computational Biology]
    [Nov 2014]

    We describe a phase plate for transmission electron microscopy taking advantage of a hitherto-unknown phenomenon, namely a beam-induced Volta potential on the surface of a continuous thin film. The Volta potential is negative, indicating that it is not caused by beam-induced electrostatic charging. The film must be heated to ∼200...
    Categories: Journal Articles
  • Flagellar motor switching dynamics [Biophysics and Computational Biology]
    [Nov 2014]

    Switching dynamics of flagellar motors of Escherichia coli is commonly observed through markers attached to the flagellar filaments. To eliminate possible complications resulting from the conformational transitions of these filaments and to look at the output of motors more directly, we monitored motor rotation by attaching nanogold spheres to the...
    Categories: Journal Articles
  • GPR56-G{alpha}12/13 signaling and muscle hypertrophy [Cell Biology]
    [Nov 2014]

    Peroxisome proliferator-activated receptor gamma coactivator 1-alpha 4 (PGC-1α4) is a protein isoform derived by alternative splicing of the PGC1α mRNA and has been shown to promote muscle hypertrophy. We show here that G protein-coupled receptor 56 (GPR56) is a transcriptional target of PGC-1α4 and is induced in humans by resistance...
    Categories: Journal Articles
  • Cog5-Cog7 crystal structure [Cell Biology]
    [Nov 2014]

    The conserved oligomeric Golgi (COG) complex is required, along with SNARE and Sec1/Munc18 (SM) proteins, for vesicle docking and fusion at the Golgi. COG, like other multisubunit tethering complexes (MTCs), is thought to function as a scaffold and/or chaperone to direct the assembly of productive SNARE complexes at the sites...
    Categories: Journal Articles
  • Fe atom catalysis and diffusion at graphene edges [Chemistry]
    [Nov 2014]

    Single-atom catalysts are of great interest because of their high efficiency. In the case of chemically deposited sp2 carbon, the implementation of a single transition metal atom for growth can provide crucial insight into the formation mechanisms of graphene and carbon nanotubes. This knowledge is particularly important if we are...
    Categories: Journal Articles
  • Mammalian adaptation of two-component signaling [Computer Sciences]
    [Nov 2014]

    Signaling pathway engineering is a promising route toward synthetic biological circuits. Histidine–aspartate phosphorelays are thought to have evolved in prokaryotes where they form the basis for two-component signaling. Tyrosine-serine–threonine phosphorelays, exemplified by MAP kinase cascades, are predominant in eukaryotes. Recently, a prokaryotic two-component pathway was implemented in a plant species...
    Categories: Journal Articles
  • Oct4 regulates mitosis [Developmental Biology]
    [Nov 2014]

    Rapid progression through the cell cycle and a very short G1 phase are defining characteristics of embryonic stem cells. This distinct cell cycle is driven by a positive feedback loop involving Rb inactivation and reduced oscillations of cyclins and cyclin-dependent kinase (Cdk) activity. In this setting, we inquired how ES...
    Categories: Journal Articles
  • Direct numerical simulations of wind ripples [Earth, Atmospheric, and Planetary Sciences]
    [Nov 2014]

    Aeolian sand beds exhibit regular patterns of ripples resulting from the interaction between topography and sediment transport. Their characteristics have been so far related to reptation transport caused by the impacts on the ground of grains entrained by the wind into saltation. By means of direct numerical simulations of grains...
    Categories: Journal Articles