Letters in 2012

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  • The crystal structure of prolyl tRNA synthetase simultaneously bound to its substrate ATP and its inhibitor halofuginone, a derivative of a compound used to treat malaria, indicates that (through interactions with ATP) halofuginone occupies both the amino acid and tRNA binding sites on the synthetase, revealing a new model for developing synthetase inhibitors.

    • Huihao Zhou
    • Litao Sun
    • Paul Schimmel
    Letter
  • Topologically distinct colloidal particles introduced into a nematic liquid crystal align and generate topology-constrained three-dimensional director fields and defects in the liquid crystal fluid that can be manipulated with a variety of methods, opening up a new area of exploration in the field of soft matter.

    • Bohdan Senyuk
    • Qingkun Liu
    • Ivan I. Smalyukh
    Letter
  • To identify comprehensively factors involved in RNAi and microRNA-mediated gene expression regulation, this study performed a phylogenetic analysis of 86 eukaryotic species; the candidates this approach highlighted were subjected to Bayesian analysis with transcriptional and proteomic interaction data, identifying protein orthologues of already known RNAi silencing factors, as well as other hits involved in splicing, suggesting a connection between the two processes.

    • Yuval Tabach
    • Allison C. Billi
    • Gary Ruvkun
    Letter
  • When an odour activates a fly′s antennae asymmetrically, more neurotransmitter is released from olfactory receptor neuron axon branches ipsilateral to the antenna than from contralateral branches. This causes ipsilateral central olfactory neurons to begin spiking earlier and at a higher rate than contralateral neurons, thereby enabling a walking fly to turn towards the odour.

    • Quentin Gaudry
    • Elizabeth J. Hong
    • Rachel I. Wilson
    Letter
  • Lymphocyte migration in the spleen is visualized live in mice using a real-time two-photon laser-scanning microscopy approach revealing that marginal zone and follicular B cells are highly motile and can shuttle between compartments, and integrin adhesion is the key to cellular retention in the marginal zone.

    • Tal I. Arnon
    • Robert M. Horton
    • Jason G. Cyster
    Letter
  • A thermal analogue of a superconducting quantum interference device (SQUID, widely used to measure small magnetic fields) is realized, in which the flow of heat between the superconductors is dependent on the quantum phase difference between them.

    • Francesco Giazotto
    • María José Martínez-Pérez
    Letter
  • Evaporative cooling of molecules has not been achieved so far, owing to unfavourable collision properties and trap losses; microwave-forced evaporative cooling of hydroxyl molecules loaded in a magnetic quadrupole trap is now reported.

    • Benjamin K. Stuhl
    • Matthew T. Hummon
    • Jun Ye
    Letter
  • Globular clusters can be grouped into a few distinct families on the basis of the radial distribution of ‘blue stragglers’, stars with masses greater than those at the turn-off point on the main sequence; this grouping can yield a direct measure of the cluster’s dynamical age purely from observed properties.

    • F. R. Ferraro
    • B. Lanzoni
    • A. Mucciarelli
    Letter
  • Neutron scattering measurements on single-crystal samples of the mineral herbertsmithite, which is a spin-1/2 kagome-lattice antiferromagnet, provide evidence of fractionalized spin excitations at low temperatures, indicating that the ground state of herbertsmithite may be a quantum spin liquid.

    • Tian-Heng Han
    • Joel S. Helton
    • Young S. Lee
    Letter
  • Measurements of the viscous anisotropy of highly deformed polycrystalline olivine find it to be approximately an order of magnitude larger than that predicted by grain-scale simulations; the maximum degree of anisotropy is reached at geologically low shear strain, such that deforming regions of the Earth’s upper mantle should exhibit significant viscous anisotropy.

    • L. N. Hansen
    • M. E. Zimmerman
    • D. L. Kohlstedt
    Letter
  • An ex vivo primary culture assay is developed that recapitulates mouse embryonic mesodermal patterning and segment formation; using this approach, it is shown that oscillating gene activity is central to maintain stable proportions during development.

    • Volker M. Lauschke
    • Charisios D. Tsiairis
    • Alexander Aulehla
    Letter
  • The Gossypium genus is used to investigate emergent consequences of polyploidy in cotton species; comparative genomic analyses reveal a complex evolutionary history including interactions among subgenomes that result in genetic novelty in elite cottons and provide insight into the evolution of spinnable fibres.

    • Andrew H. Paterson
    • Jonathan F. Wendel
    • Jeremy Schmutz
    LetterOpen Access
  • Comparative analysis of the genomes of one mollusc (Lottia gigantea) and two annelids (Capitella teleta and Helobdella robusta) enable a more complete reconstruction of genomic features of the last common ancestors of protostomes, bilaterians and metazoans; against this conserved background they provide the first glimpse into lineage-specific evolution and diversity of the lophotrochozoans.

    • Oleg Simakov
    • Ferdinand Marletaz
    • Daniel S. Rokhsar
    LetterOpen Access
  • Rare truncating mutations in the p53-inducible protein phosphatase PPM1D are shown to be associated with predisposition to breast cancer and ovarian cancer; notably, all of the mutations are mosaic in white blood cells but are not present in tumours, and probably have a gain-of-function effect.

    • Elise Ruark
    • Katie Snape
    • Nazneen Rahman
    Letter