This press release contains:
· Summaries of newsworthy papers:
Relics: Burgess Shale-like fossils live on
Nanotechnology: DNA robots get to work
Opinion: Taking the global temperature
Astronomy: White dwarfs — the inside story
Opinion: Let’s vaccinate before the next pandemic
Earth science: Erosion of confidence
Physics: A quantum-optical transistor
Neuroscience: Phosphatase helps maintain brain integrity
And finally… Spider silk’s dual identity
· Mention of papers to be published at the same time with the
same embargo
· Geographical listing of authors
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[1] Relics: Burgess Shale-like fossils live on (pp 215-218)
Soft-bodied Burgess Shale-like creatures may have persisted beyond the Cambrian period, new fossil finds suggest.
The Burgess Shale of British Columbia is famous for having yielded fossils of soft-bodied creatures from the Middle Cambrian, offering a window onto early animal life in the sea. Similar faunas have been found in localities as far apart as China and Greenland, but it's unclear whether these creatures died out before the end of the Cambrian.
In this week's Nature, Derek Briggs and colleagues describe numerous, diverse soft-bodied fauna found in southeastern Morocco and dated to the post-Cambrian Ordovician period. The finds indicate that poor preservation rather than mass extinction is the reason for the apparent disappearance of Burgess Shale-type fauna from the post-Cambrian fossil record.
Autho contact
Derek Briggs (Yale University, New Haven, CT, USA)
Tel: +1 203 432 8590
E-mail: [email protected]
[2] & [3] Nanotechnology: DNA robots get to work (pp 202-210; N&V)
Molecular machines based on DNA have attained new levels of autonomy and complexity in the tasks they can perform, as shown in two Nature papers this week.
The new studies both use DNA walkers — motile molecules with DNA ‘legs’, which can move from one binding site to another across a DNA-covered surface. Milan Stojanovic and colleagues show that a type of DNA walker called a ‘molecular spider’ can act as an autonomous robot by following cues programmed into its environment. The spider’s legs are DNA enzymes, which can cleave a particular substrate sequence of DNA. The authors lay a track of substrate molecules on a two-dimensional surface, which the spider follows, modifying the surface as it goes. A ‘stop’ command is encoded by a region containing uncleavable strands. The authors observe their robots traversing distances of up to 100 nanometres (up to 50 cleavage steps), guided by the DNA landscape.
In another study, Nadrian Seeman and colleagues create a nanoscale ‘assembly line’, in which DNA walkers move past programmable DNA machines that can deliver ‘cargo’ (gold nanoparticles) to the walkers. In addition to four ‘legs’, the DNA walkers have three ‘hands’ that accept the cargo. The assembly line has three DNA machines, each of which holds a different type of cargo, and can be set either to transfer its cargo to the walker, or to withhold it. In this way, the nano-assembler can be programmed to produce eight (23 ) different ‘products’, all with usefully high yields.
In an accompanying News and Views article, Lloyd Smith notes that the assembly line of Seeman and colleagues marks a milestone in DNA nanotechnology, in using ‘systems of nanomachines, rather than individual devices’ to perform an operation. He also discusses the trade-off between autonomy and complexity in the two studies.
Author contact
Milan Stojanovic (Columbia University, New York, NY, USA) – Author paper [2]
Tel: +1 212 342 5610
E-mail: [email protected]
Nadrian Seeman (New York University, NY, USA) – Author paper [3]
Tel: +1 212 998 8395
E-mail: [email protected]
Lloyd Smith (University of Wisconsin, Madison, WI, USA) N&V author
Tel: +1 608 263 2594
E-mail: [email protected]
Opinion: Taking the global temperature (pp 158-159)
In February, scientists from the UK Met Office called for a new international project to standardize global temperature records. In an Opinion piece in this week’s Nature, Peter Stott from the Met Office in Exeter, and Peter Thorne, now at the NOAA Cooperative Institute for Climate and Satellites in North Carolina, USA, explain why this is necessary and how it might work.
The climate community needs to gather all local daily and sub-daily temperature measurements into a single global database and then correct that data (for variations caused by changes in instrument location, for example) in a transparent way, they say. The results would show temperature changes on an hourly level, within distances of a few kilometres. Such fine-scale data will be critical for monitoring and predicting local climate effects.
This project will build on the World Data Center archive, which already holds detailed observations from more than 6,000 weather stations. The hard part will be to add data currently protected by commercial rights. Some national weather services are obliged to make a profit and they do so by selling their detailed weather observations, making it hard for scientists to get free access to the data, Stott and Thorne say. Correcting the data also requires new techniques that will need development.
The Met Office’s plan has been endorsed by the World Meteorological Organization, and a workshop will be held in September to work out the details.
Author contact
Peter Stott (Met Office, Exeter, UK)
Tel: +44 7753 880683
E-mail: [email protected]
Peter Thorne (Cooperative Institute for Climate and Satellites,
Asheville, NC, USA)
Tel: +44 7834 034418
E-mail: [email protected]
[4] Astronomy: White dwarfs — the inside story (pp194-196)
A detailed model of the internal evolution of white dwarf stars has solved a puzzle regarding the age of a well studied star cluster in our Galaxy. The result, reported in this week’s Nature, provides evidence for the segregation of elements from one another in the cores of cooling white dwarfs.
The open star cluster NGC 6791 seems to have formed about 8 billion years ago, based on the age of its oldest main-sequence stars. But another dating method, based on the cooling history of white dwarfs, has yielded a much younger age, of only 6 billion years. A possible explanation for the discrepancy is that physical separation of elements in the cooling white dwarfs releases gravitational energy, which heats the stars, prolonging their cooling times. In this case, models that neglect such separation effects would underestimate a star’s age.
Enrique García-Berro and colleagues have now calculated the evolution of the white-dwarf population of NGC 6791, using a physical model that includes sinking of neon-22 in the star’s liquid interior, followed by separation of solid carbon-12 and oxygen-16 when the core has cooled further. Using this model, they derive a cooling age of 8 ± 0.2 billion years for the white dwarfs in NGC 6791 — resolving the age discrepancy, and showing that white dwarfs can be used as reliable chronometers.
Author contact
Enrique García-Berro (Universitat Politècnica de Catalunya, Castelldefels, Spain)
Tel: +34 93 413 41 43
E-mail: [email protected]
Opinion: Let’s vaccinate before the next pandemic (p. 161)
In an Opinion piece this week in Nature, Klaus Stöhr of Novartis argues that pre-pandemic immunization with a cocktail of likely strains is a cheaper, more practical and equitable way to protect people against influenza. “This could limit the spread of the virus in the early stages of a pandemic and significantly reduce the peak demand for vaccine,” Stöhr writes. He argues that this approach would free up supply during a pandemic for countries where vaccination had been patchy beforehand, or that do not have the infrastructure or budget to purchase any vaccine.
During the recent H1N1 flu pandemic, despite a record rate of vaccine production, only enough was produced to cover 10% of the world’s population. In the aftermath of this, the stage is set, says Stöhr, for a global public-health leader, such as the World Health Organization, to carry out an in-depth assessment into the practicalities and cost-effectiveness of this contentious approach and its long-term effect on public health. One thing is clear, he concludes, “something has to change, because the current approach leaves at least 80% of the world’s population unprotected in the face of a new pandemic, most of them in developing countries — and that is unacceptable”.
Author contact
Klaus Stöhr (Novartis Vaccines and Diagnosis, Cambridge, MA, USA)
Tel: +1 617 259 6132
E-mail: [email protected]
[5] Earth science: Erosion of confidence (pp 211-214; N&V)
A long-standing question for Earth scientists has been the cause of an apparent fourfold increase in global sedimentation rates during the past five million years. Mountains forming at a faster rate and a decrease in global temperatures have both been suggested as possible causes.
In this week’s Nature, Jane Willenbring and Friedhelm von Blanckenburg reanalyse original data sets and use ocean records of beryllium isotope ratios to obtain an indirect measure of past erosion rates. Their observations indicate that no increase in global erosion over the past 12 million years has occurred. They propose that processes other than increased denudation have caused Cenozoic global cooling and that global cooling had on average no significant effect on the Earth’s erosion rates.
Author contact
Jane Willenbring (Deutsches GeoForschungsZentrum, Potsdam, Germany)
Tel: +49 331 288 286000
E-mail: [email protected]
Yves Goddéris (Université de Toulouse III, France) N&V author
Tel: +33 5 61 33 26 15
E-mail: [email protected]
[6] Physics: A quantum-optical transistor (AOP)
DOI: 10.1038/nature09093
This paper will be published electronically on Nature's website on 12 May at 1800 London time / 1300 US Eastern Time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 13 May, but at a later date.
A single atom, trapped in an optical cavity, has been used as a ‘quantum-optical transistor’, to control the transmission of light through the cavity. The result, published online this week in Nature, lays the groundwork for full quantum control of the generation, propagation and absorption of light.
Eden Figueroa and colleagues based their work on the phenomenon of lectromagnetically induced transparency, in which the transmission of laser light through an optically dense medium is controlled by a second laser beam. The authors succeeded in scaling the effect down to just a single atom, by taking advantage of the strong interaction between matter and light provided by an appropriately designed optical cavity.
The single-atom system can switch the intensity of transmitted light by 20% — a figure that the authors say can be improved to 90% or more. This ability of single atoms to control the light field, when extended to systems of many individually addressable atoms, will provide a basis for true quantum networks, in which quantum information can be transferred in a coherent fashion between matter and light. It may also lead to novel applications, such as precise control of the number of photons in a propagating light beam.
Author contact
Eden Figueroa (Max Planck Institut für Quantenoptik, Garching, Germany)
Tel: +49 89 32905 333
E-mail: [email protected]
[7] Neuroscience: Phosphatase helps maintain brain integrity (AOP)
DOI: 10.1038/nature09023
This paper will be published electronically on Nature's website on 12 May at 1800 London time / 1300 US Eastern Time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 13 May, but at a later date.
A newly discovered link between an enzyme involved in phosphate removal and the regulation of neurodegeneration is published online in Nature this week. Understanding the neuroprotective role of this enzyme boosts our knowledge of the progression of neurodegenerative disorders.
Inositol polyphosphate phosphatase 4A (INPP4A) protects neurons from a kind of cell death, where excessive glutamate receptor activation becomes toxic to nerve cells. Mice lacking the enzyme suffer neuronal cell death in the striatum and experience severe involuntary movements, a picture that tallies with this ‘excitotoxic’ mode of cell death.
Excitotoxic cell death has previously been implicated in various neurodegenerative disorders including Huntington’s chorea an Parkinson’s disease. Junko Sasaki and colleagues suspect that the protein helps to keep neurons alive by downregulating specific glutamate receptors and so decreasing cell sensitivity to glutamate. The authors hope that their work will aid the development of new approaches for the treatment of these types of disorders.
Author contact
Junko Sasaki (Akita University, Japan)
Tel: +81 18 884 6080
E-mail: [email protected]
[8] & [9] And finally… Spider silk’s dual identity (pp 236-242)
The mechanism behind spider silk’s versatility is investigated by two papers in Nature this week. The research reveals a molecular switch that could be applicable to the design of versatile fibrous materials.
Nature’s very own high-performance polymer, spider silk, consists of proteins known as spidroins that are stored as a highly concentrated fluid. When the silk is formed, intermolecular interactions provide strength and elasticity.
Stefan Knight and colleagues present the tri-dimensional structure of the N-terminal domain of silk proteins from the nursery web spider Euprosthenops australis. They show that this domain can regulate silk assembly by preventing premature aggregation of spidroins and triggering polymerization as the pH falls along the spider’s spinning apparatus.
Meanwhile, Horst Kessler and his team publish the structure of the C-terminal domain from the common orb-weaver Araneus diadematus. They observe a conformational switch in the C-terminal domain in response to chemical or mechanical stimuli, between storage and assembly forms of the protein. The work helps to explain why this material is remarkably soluble when stored at high concentration yet can convert to extremely sturdy fibres on demand.
Author contact
Stefan Knight (Swedish University of Agricultural Sciences, Uppsala, Sweden) – Author paper [8]
Tel: +46 18 47 14554
E-mail: [email protected]
Horst Kessler (University of Technology Munich, Germany) – Author paper [9]
Tel: +49 89 289 13300
E-mail: [email protected]
ALSO IN THIS ISSUE…
[10] A formal test of the theory of universal common ancestry (pp 219-222; N&V)
[11] Single-molecule dynamics of gating in a neurotransmitter transporter homologue (p188-193; N&V)
[12] Time-resolved observation of coherent multi-body interactions in quantum phase revivals (pp197-201)
[13] Induction of tumour immunity by targeted inhibition of nonsense-mediated mRNA decay (pp 227-230)
ADVANCE ONLINE PUBLICATION…
This paper will be published electronically on Nature's website on 12 May at 1800 London time / 1300 US Eastern Time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 13 May, but at a later date.
[14] Affinity gradients drive copper to cellular destinations
DOI: 10.1038/nature09018
GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.
ARGENTINA
La Plata: 4
San Juan: 4
AUSTRALIA
Clayton: 7
BRAZIL
São Paulo: 6
CHINA
Nanjing: 3
ESTONIA
Tallinn: 14
FRANCE
Villeurbanne: 1
GERMANY
Bayreuth: 9
Garching: 6, 9, 12
Hamburg: 12
Mainz: 12
Munich: 12
Potsdam: 5
Tübingen: 9
IRELAND
Dublin: 1
ITALY
Florence: 14
JAPAN
Akita: 7
Fukuoka: 7
Gunma: 7
Kobe: 7
Tokyo: 7
MOROCCO
Marrakech: 1
NORWAY
Oslo: 8
SPAIN
Barcelona: 4
Bellaterra: 4
Castelldefels: 4
Madrid: 8
SWEDEN
Uppsala: 8
UNITED KINGDOM
Birkenhead: 4
Huddersfield: 1
Leeds: 1
UNITED STATES OF AMERICA
Arizona
Tempe: 2
California
Pasadena: 2
Connecticut
New Haven: 1
Florida
Miami: 13
Iowa
Iowa City: 13
Massachusetts
Waltham: 10
Michigan
Ann Arbor: 2
New York
New York: 3, 11
PRESS CONTACTS…
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From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, (Nature Tokyo)
Tel: +81 3 3267 8751
E-mail: [email protected]
From the UK
Rebecca Walton, (Nature, London)
Tel: +44 20 7843 4502
E-mail: [email protected]
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