Volume 459 Issue 7244, 14 May 2009

qiRNAs are a novel class of small RNAs identified by Heng-Chi Lee et al. in the filamentous fungus Neurospora, where they may play a role in DNA repair as inhibitors of protein translation. The cover shows a rosette of maturing Neurospora asci with fluorescing binucleate ascospores, indicated by GFP-histone H1. [Cover photo by Namboori B. Raju, and modified by Heng-chi Lee and Allen Tsai.]

Authors

Editorials

  • Editorial |

    The European Parliament has reaffirmed its legislative value by reversing the potentially disruptive restrictions in the draft directive for protecting laboratory animals.

  • Editorial |

    Last year's earthquake in China is a salutary reminder about preparing for risk in the face of uncertainty.

  • Editorial |

    The extraordinary emerging images of ocean microbiology need the fourth dimension of time.

Research Highlights

Journal Club

News

News in Brief

Features

  • News Feature |

    The great Sichuan earthquake of 12 May 2008 caught Earth scientists off guard. A year on, Alexandra Witze reports from the shattered towns on how researchers have learned from their failures.

    • Alexandra Witze
  • News Feature |

    Bacteria and their hosts may reside in different kingdoms, but that doesn't stop them from intercepting each other's communications. Asher Mullard reports.

    • Asher Mullard

Correspondence

Essay

  • Essay |

    Scientists and philosophers are using new discoveries in neuroscience to question the idea of free will. They are misguided, says Martin Heisenberg. Examining animal behaviour shows how our actions can be free.

    • Martin Heisenberg

Books and Arts

  • Books & Arts |

    As scientists discover more about the genomes of marine microorganisms, new views of their physiology and ecosystem networks are opening up, explain Alexandra Z. Worden and Darcy McRose.

    • Alexandra Z. Worden
    •  & Darcy McRose
  • Books & Arts |

    In her documentary Between the Folds, film director Vanessa Gould explores the expression of mathematics through origami. She tells Nature how she became captivated by the art and science of transforming sheets of paper into three-dimensional geometric shapes — and exposed a hidden subculture.

    • Roxanne Khamsi

News & Views

  • News & Views |

    Understanding how life emerged on Earth is one of the greatest challenges facing modern chemistry. A new way of looking at the synthesis of RNA sidesteps a thorny problem in the field.

    • Jack W. Szostak
  • News & Views |

    The parasitic microorganism Trypanosoma brucei evades recognition by its host's immune system by repeatedly changing its surface coat. The switch in coat follows a risky route, though: DNA break and repair.

    • Dave Barry
    •  & Richard McCulloch
  • News & Views |

    The outburst of a Sun-like star offers a rare opportunity to witness the making of silicate crystals in the star's planet-forming disk, providing key information about the formation of comets and the Solar System.

    • Aigen Li
  • News & Views |

    Discovery of the sexually explicit figurine of a woman, dating to 35,000 years ago, provides striking evidence of the symbolic explosion that occurred in the earliest populations of Homo sapiens in Europe.

    • Paul Mellars

Insight

Articles

  • Article |

    The differentiation of the parasite Trypanosoma brucei, the cause of sleeping sickness, from the human blood to the tsetse fly stage is known to require two signals – low temperature and citrate and/or cis-aconitate – but how these signals were perceived was unknown. The trypanosome carboxylate-transporter family PAD is now revealed to be essential in this process.

    • Samuel Dean
    • , Rosa Marchetti
    • , Kiaran Kirk
    •  & Keith R. Matthews
  • Article |

    Individual odorant molecules have been shown to activate several distinct classes of olfactory neurons at once, suggesting a combinatorial code. Using a new behavioural assay and cutting-edge genetic control of specific neurons in the fruitfly, attraction to low concentrations of vinegar is now shown to rely exclusively on one or two of the six activated neuronal centres.

    • Julia L. Semmelhack
    •  & Jing W. Wang

Letters

  • Letter |

    Our Solar System originated in a cloud of interstellar gas and amorphous dust, but cometary dust is mainly crystalline—and it is not clear how this crystallization occurred. The outburst spectrum of the young solar-like star EX Lupi shows mid-infrared features, attributed to crystalline forsterite, that were not present in quiescence, suggesting that crystals were produced via thermal annealing by heat from the outburst. This represents a new mechanism of crystal formation in protoplanetary disks.

    • P. Ábrahám
    • , A. Juhász
    • , C. P. Dullemond
    • , Á. Kóspál
    • , R. van Boekel
    • , J. Bouwman
    • , Th. Henning
    • , A. Moór
    • , L. Mosoni
    • , A. Sicilia-Aguilar
    •  & N. Sipos
  • Letter |

    Dusty disks around young stars are formed out of interstellar dust that consists of amorphous submicrometre grains. Yet the grains found in comets, meteorites and traced in the spectra of young stars include big crystalline grains in environments considered too cold for crystallinity to occur. Here it is shown that infrared light arising from the dusty disk can loft grains bigger than one micrometre out of the hot inner disk, whereupon they are pushed outwards by stellar radiation pressure.

    • Dejan Vinković
  • Letter |

    When the packing fraction is increased sufficiently, loose particulates jam together to form a rigid solid in which the constituents are no longer free to move. Although in typical granular materials and foams the thermal energy is too small to produce structural rearrangements, thermal motion becomes relevant when the particles are small enough. Here, colloidal experiments and computer simulations are used to investigate the overlap distance between neighbouring particles beyond the zero-temperature limit, revealing some surprising behaviour.

    • Zexin Zhang
    • , Ning Xu
    • , Daniel T. N. Chen
    • , Peter Yunker
    • , Ahmed M. Alsayed
    • , Kevin B. Aptowicz
    • , Piotr Habdas
    • , Andrea J. Liu
    • , Sidney R. Nagel
    •  & Arjun G. Yodh
  • Letter |

    Light-emitting diodes based on organic materials (known as OLEDs) have a number of attractive qualities that could make them the light sources of choice for the future. Unfortunately until now they have never reached the power efficiencies of fluorescent tubes. Here, the engineering of white OLEDs with power efficiencies at least as high as that of standard fluorescent tubes brings the future a little closer.

    • Sebastian Reineke
    • , Frank Lindner
    • , Gregor Schwartz
    • , Nico Seidler
    • , Karsten Walzer
    • , Björn Lüssem
    •  & Karl Leo
  • Letter |

    At some stage in the origin of life, an information-carrying polymer must have formed by purely chemical means. That polymer might have been RNA, but until now this theory has been hampered by a lack of evidence for a plausible route in which the ribonucleotides could have formed on prebiotic Earth. Here, just such a route is reported.

    • Matthew W. Powner
    • , Béatrice Gerland
    •  & John D. Sutherland
  • Letter |

    Labrador Sea Water (LSW) is an important determinant of the strength of the Atlantic meridional overturning circulation and thus of the main oceanic mechanism of energy redistribution. By using a combination of neutral buoyancy floats and modelling 'e-floats', the dominant pathway of export of LSW into the North Atlantic is shown to be via internal pathways rather than the Deep Western Boundary Current, as previously thought.

    • Amy S. Bower
    • , M. Susan Lozier
    • , Stefan F. Gary
    •  & Claus W. Böning
  • Letter |

    Yeast secrete invertase to break down sucrose into monosaccharides that they can metabolize. However, 99% of the monosaccharides diffuse away where they can be used by other yeast cells, making this a cooperative behaviour that is susceptible to cheating by cells that do not secrete invertase. Here this is shown to be a snowdrift game, in which cheating can be profitable, but is not necessarily the best strategy if others are cheating too.

    • Jeff Gore
    • , Hyun Youk
    •  & Alexander van Oudenaarden
  • Letter |

    Human infants preferentially look at motions that make sense biologically as opposed to non-biological movements within the first days of life, an ability which is seen as a precursor for attributing intentions to others. Here it is shown that two-year-olds with autism fail to look towards point-light displays of biological motion but are attracted by other properties ignored by control children, a behavioural difference which may reflect changes in the functioning of autistic brains.

    • Ami Klin
    • , David J. Lin
    • , Phillip Gorrindo
    • , Gordon Ramsay
    •  & Warren Jones
  • Letter |

    Lrg5+ is a protein which has been shown to mark cycling stem cells that renew the tissue of the intestine. Here, Lrg5+ stem cells were used in the establishment of long-term culture conditions capable of generating organoids with all the cell types and architecture of intestinal crypts present in adult mammals.

    • Toshiro Sato
    • , Robert G. Vries
    • , Hugo J. Snippert
    • , Marc van de Wetering
    • , Nick Barker
    • , Daniel E. Stange
    • , Johan H. van Es
    • , Arie Abo
    • , Pekka Kujala
    • , Peter J. Peters
    •  & Hans Clevers
  • Letter |

    Microbial gene expression in the environment has recently been assessed via pyrosequencing of total RNA extracted directly from natural, uncultured microbial communities. This technique, known as metatranscriptomics, is used to show that a significant fraction of transcripts extracted from an oceanic sample are small RNAs.

    • Yanmei Shi
    • , Gene W. Tyson
    •  & Edward F. DeLong
  • Letter |

    Malaria drug development remains an important public health goal, especially in light of the emergence of drug resistance. Here a new class of malaria drugs is presented: an acridone derivative containing a chemosensitizing domain that may prevent the occurrence of parasite drug resistance.

    • Jane X. Kelly
    • , Martin J. Smilkstein
    • , Reto Brun
    • , Sergio Wittlin
    • , Roland A. Cooper
    • , Kristin D. Lane
    • , Aaron Janowsky
    • , Robert A. Johnson
    • , Rozalia A. Dodean
    • , Rolf Winter
    • , David J. Hinrichs
    •  & Michael K. Riscoe
  • Letter |

    High-throughput sequencing has highlighted a vast reservoir of small non-coding RNAs, the function of which, for the most part, remains to be determined. Here a new class of small RNAs, termed qiRNAs, is identified from the fungus Neurospora. The production of qiRNAs is dependent on DNA damage, and it is proposed that they may have a role in the DNA damage response.

    • Heng-Chi Lee
    • , Shwu-Shin Chang
    • , Swati Choudhary
    • , Antti P. Aalto
    • , Mekhala Maiti
    • , Dennis H. Bamford
    •  & Yi Liu
  • Letter |

    Sleeping sickness is caused by the parasite Trypanosoma brucei. This parasite outwits the human immune system by periodically changing its coat protein in a process known as VSG switching. Here, the first in vitro system that recapitulates VSG switching is established, indicating that a spontaneous double-stranded DNA break upstream of the gene encoding the code protein initiates the process.

    • Catharine E. Boothroyd
    • , Oliver Dreesen
    • , Tatyana Leonova
    • , K. Ina Ly
    • , Luisa M. Figueiredo
    • , George A. M. Cross
    •  & F. Nina Papavasiliou

Futures

  • Futures |

    A Friend for life.

    • Madeline Ashby

Naturejobs

  • News |

    New US energy research centres will create 1,100 new posts for postdocs, graduate students and technicians.

    • Virginia Gewin
  • Postdoc Journal |

    Could attending an annual meeting help me decide on academia versus industry?

    • Bryan Venters
  • Career Brief |

    US legislators aim to boost number of federally supported teaching-hospital posts.

  • Career Brief |

    US biomedical research coalition launches pages on Facebook and Twitter.

  • Regions |

    The Boston-area biotechnology cluster is one of the most successful on the planet. But competition is growing from other states and countries. Heidi Ledford reports on what the region is doing to maintain its edge.

    • Heidi Ledford

Insight

  • Insight |

    Microbial oceanography

    Microorganisms are the most abundant lifeforms in the ocean, and as such have a very important role in many ecosystems. New technologies are allowing scientists to dig deeper than ever before into the composition and activity of microbial communities.

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