Volume 458 Issue 7236, 19 March 2009

On the cover, a pollen tube has been lured into growth in an ‘N-like’ pattern, following a trail of the newly discovered chemical attractant LURE1. The elusive secreted guidance factors, critical for the successful fertilization of flowering plants, have now been identified by Okuda et al. as cysteine-rich polypeptides belonging to the sub group of defensin-like proteins. [Cover image: Satohiro Okuda]

Authors

Editorial

  • Editorial |

    Turkey's government has done more for science than many. A row over a censored magazine and a sacked editor could put the good work at risk.

  • Editorial |

    President Obama's funds for electronic health records should prompt research — and controversy.

  • Editorial |

    As science journalism declines, scientists must rise up and reach out.

Research Highlights

Correction

Journal Club

News

News in Brief

News Feature

  • News Feature |

    The switch to electronic medical records opens up a potential wealth of data for researchers, if major obstacles can be overcome, reports Katharine Gammon.

    • Katharine Gammon

Correspondence

Essay

  • Essay |

    Wendy Barnaby was asked to write a book about water wars — then the facts got in the way of her story.

    • Wendy Barnaby

Books & Arts

News & Views

  • News & Views |

    The handedness of chiral molecules can be probed spectroscopically, but acquiring data can take hours, which is a problem for time-resolved studies. The latest method records such data in a flash.

    • Patrick H. Vaccaro
  • News & Views |

    Oncologists use drugs that limit a tumour's blood supply to prevent its growth. Although the initial effects of these drugs are beneficial to patients, new data suggest that their long-term effects warrant further study.

    • Lee M. Ellis
    •  & David A. Reardon
  • News & Views |

    Studies of rocks from Earth's crust suggest that the lower crust is a good thermal insulator. The knock-on effects of this finding are many — one being the crust's increased potential to generate more magma.

    • Jean Braun
  • News & Views |

    Cretaceous fossil deposits in China are famous for their feathered dinosaurs. But the surprising discovery of a herbivorous dinosaur with a filamentous coat raises fresh questions about the evolution of feathers.

    • Lawrence M. Witmer
  • News & Views |

    During the past five million years, the West Antarctic ice sheet has waxed and waned in size. A two-pronged reconstruction of that history provides clues to the ice sheet's future behaviour.

    • Philippe Huybrechts
  • News & Views |

    How does the brain organize all of the information stored in memory? On the basis of a state-of-the-art imaging study of neuronal activity in real time, the answer seems to be, through specificity in space and time.

    • Scott M. Thompson
    •  & Hayley A. Mattison

Article

  • Article |

    This study has developed a new imaging technology to track the activation of CaMKII locally within an individual dendritic spine. CaMKII is transiently activated during synaptic potentiation and does not spread to neighbouring dendritic domains, thus ensuring that synaptic changes remain localized.

    • Seok-Jin R. Lee
    • , Yasmin Escobedo-Lozoya
    • , Erzsebet M. Szatmari
    •  & Ryohei Yasuda
  • Article |

    The authors used de novo protein design to generate a simple unnatural oxygen transport protein, akin to human neuroglobin; the design strategy involved the assembly of a short helix-forming sequence into a four-helix bundle that contained histidine residues at key positions. The O2 on-rate, off-rate and dissociation constants are similar to those of human neuroglobin and other naturally occurring globins.

    • Ronald L. Koder
    • , J. L. Ross Anderson
    • , Lee A. Solomon
    • , Konda S. Reddy
    • , Christopher C. Moser
    •  & P. Leslie Dutton

Letter

  • Letter |

    Circular dichroism spectroscopy can determine optical activity in a time-resolved manner, raising the exciting prospect of directly mapping structural changes of important chemical or biological processes involving chiral molecules. Rhee et al. have overcome experimental difficulties to show that optical activity in the infrared can be detected with femtosecond time-resolution by heterodyned spectral interferometry, setting the stage for making 'molecular motion pictures' of fundamental processes from a chiral perspective.

    • Hanju Rhee
    • , Young-Gun June
    • , Jang-Soo Lee
    • , Kyung-Koo Lee
    • , Jeong-Hyon Ha
    • , Zee Hwan Kim
    • , Seung-Joon Jeon
    •  & Minhaeng Cho
  • Letter |

    Rotaxanes, in which ring-shaped subunits encircle the 'axles' of molecular dumb-bells, have been mooted as possible components of molecular machines. To date, most rotaxanes are organic, but David Leigh and colleagues now report hybrid rotaxanes, which are expected to offer a far wider range of useful physical properties to molecular engineers than purely organic rotaxanes.

    • Chin-Fa Lee
    • , David A. Leigh
    • , Robin G. Pritchard
    • , David Schultz
    • , Simon J. Teat
    • , Grigore A. Timco
    •  & Richard E. P. Winpenny
  • Letter |

    The thermal evolution of planetary crust and lithosphere is governed by the rate of heat transfer by conduction, which is determined by the rock's thermal diffusivity, usually assumed to remain constant. Alan Whittington and colleagues show that thermal diffusivity in fact decreases strongly with increasing temperature, concluding that the hot middle and lower crust is a much more effective thermal insulator than previously thought; this removes the requirement for unusually high radiogenic heat production to achieve crustal melting temperatures.

    • Alan G. Whittington
    • , Anne M. Hofmeister
    •  & Peter I. Nabelek
  • Letter |

    The response of the vast West Antarctic Ice Sheet (WAIS) to climate shifts due to changes in Earth's orbit is uncertain, but there is potential for several metres of sea level change. Naish and co-authors extracted a sediment core from beneath the Ross Ice Shelf and found evidence that the WAIS periodically collapsed during the early Pliocene (3-5 million years ago); and the pattern of collapse suggests an influence of 40,000-year cycles in the tilt of Earth's rotational axis.

    • T. Naish
    • , R. Powell
    • , R. Levy
    • , G. Wilson
    • , R. Scherer
    • , F. Talarico
    • , L. Krissek
    • , F. Niessen
    • , M. Pompilio
    • , T. Wilson
    • , L. Carter
    • , R. DeConto
    • , P. Huybers
    • , R. McKay
    • , D. Pollard
    • , J. Ross
    • , D. Winter
    • , P. Barrett
    • , G. Browne
    • , R. Cody
    • , E. Cowan
    • , J. Crampton
    • , G. Dunbar
    • , N. Dunbar
    • , F. Florindo
    • , C. Gebhardt
    • , I. Graham
    • , M. Hannah
    • , D. Hansaraj
    • , D. Harwood
    • , D. Helling
    • , S. Henrys
    • , L. Hinnov
    • , G. Kuhn
    • , P. Kyle
    • , A. Läufer
    • , P. Maffioli
    • , D. Magens
    • , K. Mandernack
    • , W. McIntosh
    • , C. Millan
    • , R. Morin
    • , C. Ohneiser
    • , T. Paulsen
    • , D. Persico
    • , I. Raine
    • , J. Reed
    • , C. Riesselman
    • , L. Sagnotti
    • , D. Schmitt
    • , C. Sjunneskog
    • , P. Strong
    • , M. Taviani
    • , S. Vogel
    • , T. Wilch
    •  & T. Williams
  • Letter |

    If the West Antarctic Ice Sheet (WAIS) melted, sea levels would rise by about 5 m; such changes are thought to have occurred in the past but could not be simulated by models. Pollard and DeConto combine ice-sheet with ice-shelf modelling, and show that over the past 5 million years, the WAIS transitioned among full, intermediate, and collapsed states in only a few thousand years, suggesting possible disintegration of the WAIS if ocean temperatures in the area rise by 5 °C.

    • David Pollard
    •  & Robert M. DeConto
  • Letter |

    All the dinosaurs with feathers or similar integumentary structures have been theropods, and such feathery appurtenances have been absent among the distantly related ornithischian dinosaurs, with the possible exception of Psittacosaurus. In this paper the authors describe an ornithischian, belonging to a group of primitive ornithischian dinosaurs called heterodontosaurs, that has an all-over covering of feather-like structures, much more like those seen in theropods.

    • Xiao-Ting Zheng
    • , Hai-Lu You
    • , Xing Xu
    •  & Zhi-Ming Dong
  • Letter |

    By sequencing over seventy isolates of the domesticated baker's yeast Saccharomyces cerevisiae and its closest relative, S. paradoxus, this study describes variation in gene content, SNPs, indels, copy numbers and transposable elements, providing insights into the evolution of different lineages, phenotypic variation, domestication and population structure of Saccharomyces.

    • Gianni Liti
    • , David M. Carter
    • , Alan M. Moses
    • , Jonas Warringer
    • , Leopold Parts
    • , Stephen A. James
    • , Robert P. Davey
    • , Ian N. Roberts
    • , Austin Burt
    • , Vassiliki Koufopanou
    • , Isheng J. Tsai
    • , Casey M. Bergman
    • , Douda Bensasson
    • , Michael J. T. O’Kelly
    • , Alexander van Oudenaarden
    • , David B. H. Barton
    • , Elizabeth Bailes
    • , Alex N. Nguyen
    • , Matthew Jones
    • , Michael A. Quail
    • , Ian Goodhead
    • , Sarah Sims
    • , Frances Smith
    • , Anders Blomberg
    • , Richard Durbin
    •  & Edward J. Louis
  • Letter |

    This study provides a nucleotide-level survey of genome variation in 63 Saccharomyces cerevisiae strains sampled from different ecological niches and geographical locations. The analysis of genome-wide patterns of the nucleotide polymorphism and deletion variants discovered lays the foundation for genome-wide association studies in yeast.

    • Joseph Schacherer
    • , Joshua A. Shapiro
    • , Douglas M. Ruderfer
    •  & Leonid Kruglyak
  • Letter |

    RNA silencing is an important player in antiviral defence mechanisms. This paper provides evidence that RNA silencing possesses a systemic arm not only in plants but also in insects; systemic spread of dsRNA from cell to cell is an important component of the antiviral immune response in Drosophila.

    • Maria-Carla Saleh
    • , Michel Tassetto
    • , Ronald P. van Rij
    • , Bertsy Goic
    • , Valérie Gausson
    • , Bassam Berry
    • , Caroline Jacquier
    • , Christophe Antoniewski
    •  & Raul Andino
  • Letter |

    This paper shows that regulatory T (Treg) cells express the transcription factor IRF4, which is essential for the differentiation of TH2 effector cells. IRF4 depletion in Treg cells induces TH2-driven autoimmune disease, leading the authors to suggest that IRF4 directs a module within Treg cells that selectively suppresses TH2 responses.

    • Ye Zheng
    • , Ashutosh Chaudhry
    • , Arnold Kas
    • , Paul deRoos
    • , Jeong M. Kim
    • , Tin-Tin Chu
    • , Lynn Corcoran
    • , Piper Treuting
    • , Ulf Klein
    •  & Alexander Y. Rudensky
  • Letter |

    In this study, Higashiyama and colleagues examine pollen tube guidance in Torenia fournieri and identify the secreted guidance factors. These are cysteine-rich polypeptides belonging to the subgroup of defensin-like proteins (designated as LUREs), which are predominantly expressed in synergid cells and are required for pollen tube guidance.

    • Satohiro Okuda
    • , Hiroki Tsutsui
    • , Keiko Shiina
    • , Stefanie Sprunck
    • , Hidenori Takeuchi
    • , Ryoko Yui
    • , Ryushiro D. Kasahara
    • , Yuki Hamamura
    • , Akane Mizukami
    • , Daichi Susaki
    • , Nao Kawano
    • , Takashi Sakakibara
    • , Shoko Namiki
    • , Kie Itoh
    • , Kurataka Otsuka
    • , Motomichi Matsuzaki
    • , Hisayoshi Nozaki
    • , Tsuneyoshi Kuroiwa
    • , Akihiko Nakano
    • , Masahiro M. Kanaoka
    • , Thomas Dresselhaus
    • , Narie Sasaki
    •  & Tetsuya Higashiyama
  • Letter | | Open Access

    This study tests the importance of the intrinsic DNA sequence preferences of nucleosomes by measuring the genome-wide occupancy of nucleosomes assembled on purified yeast genomic DNA. The resulting map is similar to in vivo nucleosome maps, indicating that the organization of nucleosomes in vivo is largely governed by the underlying genomic DNA sequence.

    • Noam Kaplan
    • , Irene K. Moore
    • , Yvonne Fondufe-Mittendorf
    • , Andrea J. Gossett
    • , Desiree Tillo
    • , Yair Field
    • , Emily M. LeProust
    • , Timothy R. Hughes
    • , Jason D. Lieb
    • , Jonathan Widom
    •  & Eran Segal
  • Letter |

    In this paper Hearn et al. present the structure of an Escherichia coli long-chain fatty acid importer, FadL, which reveals an opening in the wall of its transmembrane beta-barrel. They further show that a mutant in which this opening is constricted is unable to transport substrate, and conclude that importers, like exporters, may exploit lateral diffusion for the transport of hydrophobic substrates.

    • Elizabeth M. Hearn
    • , Dimki R. Patel
    • , Bryan W. Lepore
    • , Mridhu Indic
    •  & Bert van den Berg

Prospects

  • Prospects |

    Lifting the stem-cell ban has repercussions that go beyond science ethics and disease cures.

    • Gene Russo

Special Report

  • Special Report |

    The hiring of US science faculty members has slowed considerably. Karen Kaplan tracks the administrators who are trying to keep programmes intact.

    • Karen Kaplan

Movers

Networks and Support

  • Networks and Support |

    Congresswoman seeks legislation to provide grant extensions for federally funded scientists who need extended family leave.

    • Heidi Ledford

Career View

  • Career View |

    Is my marketability more important than my curiosity?

    • Sam Walcott

Futures

  • Futures |

    A word to the wise.

    • Tony Ballantyne

Brief Communications Arising

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