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This press release is copyright Nature.
VOL.461 NO.7266 DATED 15 OCTOBER 2009
This press release contains:
· Summaries of newsworthy papers:
Neuroscience: Place in space
Neuroscience: Learning literacy
Physics: The magnetic equivalent of electricity
Quantum physics: Entangled electrons at a crossroads
Immunology: Silent attack caught on camera
Physics: Charge break-up in grapheme
Organic chemistry: New route to non-natural amino acids
Materials: Quasicrystals self-assemble
And finally… How to make flies sexually irresistible
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Neuroscience: Place in space (pp 941-946; N&V)
Patterns of electrical activity related to movement have been recorded in brain cells of awake, mobile mice. The results, published in this week’s Nature, boost our understanding of how the brain processes movement and spatial information.
David Tank and colleagues used a previously reported visual virtual-reality system in which mice move around on top of a spherical treadmill in response to a virtual environment projected around them. In this system, the mice can move their limbs but their heads stay relatively still, enabling the researchers to record from single nerve cells for minutes at a time. Three characteristic electrical ‘signatures’ related to movement were identified from place-sensitive nerve cells inside the hippocampus — the brain’s centre of learning and memory — which help the animals to determine their location in space.
The team’s set-up has the potential to be combined with two-photon laser scanning microscopy to image movement-related changes in living tissue. The virtual-reality system also offers the ability to design highly customized and changeable environments, making new types of experiments exploring spatial information possible.
CONTACT
David Tank (Princeton Universisty, NJ, USA)
Tel: +1 609 258 7371; E-mail: [email protected]
Douglas Nitz (University of California, San Diego, CA, USA) N&V author
Tel: +1 858 534 1132; E-mail: [email protected]
[2] Neuroscience: Learning literacy (pp 983-986)
Various brain regions are found to be involved in the acquisition of literacy. The study, published this week in the journal Nature, looked at changes in the brains of former Colombian guerrillas learning reading and writing for the first time.
It is difficult to study brain changes that occur due to literacy, as these skills are usually learned during childhood — a time when there are many other developmental changes in the brain. By comparing the brains of adult illiterates and literates, Manuel Carreiras and colleagues were able to focus on changes due solely to literacy.
The researchers found that the guerillas learning to read and write have greater connectivity between specific areas of the brain that are implicated in language processing. When comparing reading to a similar task, object naming, the team found that the extent of connectivity changes found in literates was exclusive to learning to read.
CONTACT
Manuel Carreiras (Basque Center on Cognition Brain and Language, Donostia, Spain)
Tel: +34 944052660; E-mail: [email protected]
[3] Physics: The magnetic equivalent of electricity (pp 956-959; N&V)
Magnetic monopoles — single magnetic charges that act like an isolated north or south pole of a bar magnet — have been observed to behave and interact just like more familiar electric charges, demonstrating a perfect symmetry between electricity and magnetism.
Steven Bramwell and colleagues, who report their findings in this week’s Nature, used an elegant combination of theory and experiment to probe the behaviour of magnetic monopoles in a type of material called spin ice. Magnetic monopoles were first predicted to exist in 1931, but despite many searches, they have never yet been observed as freely roaming elementary particles. The monopoles observed by the team arise as disturbances of the ordered magnetic state of the spin ice Dy2Ti2O7, and can exist only inside the material.
In a nice illustration of the fundamental nature of electromagnetism, the authors adapted a theory first developed to describe the behaviour of electric charges in a liquid to the case of magnetic charges in a ‘sea’ of magnetic dipoles — the lattice of the spin ice. The experimental demonstration of this electricity–magnetism equivalence allowed them to detect magnetic charges in Dy2Ti2O7, to measure their currents, and to determine the elementary unit of the magnetic charge in the material.
CONTACT
Steven Bramwell (London Centre for Nanotechnology, University College London, UK)
Tel: +44 20 7679 7463; E-mail: [email protected]
Shivaji Sondhi (Princeton University, NJ, USA) N&V author
Tel: +1 609 258 4326; E-mail: [email protected]
[4] Quantum physics: Entangled electrons at a crossroads (pp 960-963)
A tiny electronic device, less than two thousandths of a millimetre across, has been used to produce and then split ‘entangled’ pairs of electrons. The demonstration, published in this week’s Nature, opens the way to new tests of quantum mechanics in the solid state, and provides a possible component for quantum computing on a chip.
One of the most striking features of quantum systems is entanglement — a linking of the quantum states of spatially separated objects that cannot be explained by classical processes. Many realizations and tests of this quantum mechanical ‘cross-talk’ have been performed on pairs of photons. It has been predicted that one could do similar experiments with entangled electrons and potentially use them for quantum computing, but until now it has not been possible to prepare such electrons on demand.
Christian Schönenberger and colleagues have built a device that at its heart has a superconducting contact, in which the electrons are naturally entangled in pairs. The superconductor is connected in a ‘Y’-configuration to two quantum dots — nanoscale semiconducting islands that can be configured to accept only one electron at a time. In this way, entangled electron pairs from the superconductor can be split apart, with each one travelling down a different branch of the ‘Y’. The split pairs are produced at a sufficient rate to be used in tests of quantum theory and, in principle, for quantum computing.
CONTACT
Christian Schönenberger (University of Basel, Switzerland)
Tel: +41 61 267 3690; E-mail: [email protected]
[5] Immunology: Silent attack caught on camera (AOP)
DOI: 10.1038/nature08478
***This paper will be published electronically on Nature's website on 14 October 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 15 October, but at a later date. ***
Autoimmune-disease-triggering white blood cells have been tracked as they enter the brain in a rat model of multiple sclerosis. The study, reported in this week’s Nature, sheds new light on the brain’s immune surveillance mechanisms, as well as the steps underpinning autoimmune disease.
To enter the brain, these brain-specific T cells must first cross the protective blood-brain barrier. They do so, Alexander Flügel and colleagues show, by directly attaching to and then systematically scanning the inside of local blood vessels, sometimes crawling against the blood flow. After crossing the vessels walls, they continue to scan the outer vascular surface, and then finally, the surface of the local brain tissue. Inside the brain, the T cells come into contact with white blood cells called phagocytes, which provide crucial signals that help guide the T cells towards their final destination.
CONTACT
Alexander Flügel (Institute for Multiple-Sclerosis-Research, Göttingen, Germany)
Tel: +49 551 3913331; E-mail: [email protected]
[6] Physics: Charge break-up in graphene (AOP)
DOI: 10.1038/nature08522
***This paper will be published electronically on Nature's website on 14 October 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 15 October, but at a later date. ***
Researchers confirm that charge carriers in graphene interact strongly with each other and exhibit collective behaviour manifesting as fractions of an electron’s elementary charge. Graphene is expected to find a range of applications in future electronics and these findings are important for understanding its complex physical properties.
When charge carriers such as electrons are confined to moving in a two-dimensional plane and subject to a perpendicular magnetic field, they can form new quasi-particles with a fraction of the electron’s elementary charge. This is known as the fractional quantum Hall effect — FQHE. Graphene could be considered such a ‘perfect’ two-dimensional system because the carbon atomic constituents are arranged in a single plane. Its charge carriers are remarkably mobile and have been predicted to interact strongly with each other. But firm evidence of collective behaviour such as the FQHE has been difficult to obtain.
Eva Andrei and colleagues report the experimental observation of FQHE using devices containing suspended sheets of graphene probed in a two-terminal measurement set-up. Their approach removes disturbances from impurities that would normally obscure the effects of electron interactions, and may explain why previous searches have failed.
CONTACT
Eva Andrei (Rutgers University, Piscataway, NJ, USA)
Tel: +1 732 445 2509; E-mail: [email protected]
[7] Organic chemistry: New route to non-natural amino acids (pp 968-970)
A new method of making non-natural alpha-amino acids is revealed in this week’s Nature. The procedure should be adaptable to the large-scale synthesis of these compounds, which are needed to produce many pharmaceutical agents and other biologically active molecules.
Eric Jacobsen and his colleagues have adapted their previous Strecker synthesis with a new catalyst to replace the current relatively precious and complex ones. They identify a simple organic molecule that can catalyse the addition of cyanide to imines; the resulting compound can easily be converted into an alpha-amino acid. Their catalyst is robust and does not contain sensitive functional groups, so it is possible to use aqueous cyanide salts in this reaction, which are much safer and easier to handle than hydrogen cyanide.
Efficient methods for making alpha-amino acids do exist, but making large quantities of non-natural alpha-amino acids has been challenging until now. This new method appears to be an easier, and more environmentally friendly, way of obtaining these important compounds.
CONTACT
Eric Jacobsen (Harvard University, Cambridge, MA, USA)
Tel: +1 617 496 3688; E-mail: [email protected]
[8] Materials: Quasicrystals self-assemble (pp 964-967; N&V)
Nanoparticles can self-assemble into quasicrystalline structures, a Nature paper reveals. The new structures provide useful insights into the formation of these exquisite forms that are, by definition, both ordered and aperiodic.
Quasicrystals combine indefinite numbers of regularly repeating elements with packing symmetries, like five- and twelve-fold rotations, that are forbidden in classical crystallography. But until now, they had only been found in specific systems such as intermetallic compounds or tri-block copolymers. Dmitri Talapin and colleagues have now self-assembled nanoparticles into twelve-sided quasicrystalline superlattices by carefully tailoring their sizes and using a previously untried packing motif.
The quasicrystals can be formed from nanoparticles made from several different combinations of materials, suggesting that their formation does not require a unique combination of interparticle interactions, but is a general sphere-packing motif governed by simple interparticle potentials. The structures can also be connected to ordinary crystalline binary superlattices via a thin ‘wetting layer’, the like of which was first discussed by German mathematician Johannes Kepler in the early 17th century.
CONTACT
Dmitri Talapin (University of Chicago, IL, USA)
Tel: +1 773 834 260; E-mail: [email protected]
Alfons van Blaaderen (Utrecht University, Netherlands) N&V author
Tel: +31 30 2532 204; E-mail: [email protected]
[9] And finally… How to make flies sexually irresistible (pp 987-991; N&V)
Male and female fruitflies lacking pheromone-producing cells become hyperattractive to normal males, a Nature paper reveals. The study sheds light on the role of pheromones in mating behaviour, and identifies a single specialized cell type responsible for sexual and species recognition in fruitflies.
Joel Levine and colleagues genetically destroyed the cells that produce hydrocarbon pheromones in the cuticle of fruitflies (oenocytes), effectively creating a ‘blank slate’ with which to study chemical communication. The resulting male and female flies became sexually hyperattractive to normal male flies, and also to male flies from a different species.
Normal social and species boundaries can be restored by treating the oenocyte-less flies with individual synthetic chemicals. The study thus shows that a single compound from one specific cell type suffices to communicate sexual identity among fruitflies, and also defines a reproductive barrier that prevents D. melanogaster fruitflies from mating with sibling species.
CONTACT
Joel Levine (University of Toronto, Mississauga, Canada)
Tel: +1 905 569 4931; E-mail: [email protected]
Nicolas Gompel (Developmental Biology Institute of Marseille, France) N&V author
Tel: +33 491 269 206; E-mail: [email protected]
ALSO IN THIS ISSUE…
[10] Asymmetric centrosome inheritance maintains neural progenitors in neocortex (pp 947-955; N&V)
[11] Integrin-linked kinase (ILK) is an adaptor with essential functions during mouse development (pp 1002-1006)
[12] DNA demethylation in hormone-induced transcriptional derepression (pp 1007-1012)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 14 October 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 15 October, but at a later date. ***
[13] Human DNA methylomes at single-base resolution reveal widespread cell-specific epigenetic signatures
DOI: 10.1038/nature08514
*** The following paper will be published electronically on Nature’s website on 09 October at 1400 London time / 0900 US Eastern time, which is when the embargo will lift. Please note that the rest of the above articles on this press release remain under embargo until 14 October at 1800 London time / 1300 US Eastern time ***
[14] RNA polymerase II–TFIIB structure and mechanism of transcription initiation
DOI: 10.1038/nature08548
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.
AUSTRALIA
Perth: 13
CANADA:
Halifax: 5
Mississauga: 9
COLOMBIA
Bogota: 2:
DENMARK
Copenhagen: 4
FINLAND
Helsinki: 11
FRANCE
Grenoble: 3
GERMANY
Erlangen: 5
Goettingen: 5
Martinsried: 5, 11
Munich: 5, 14
Regensberg: 14:
HUNGARY
Budapest: 4
JAPAN
Saitama: 12
Tokyo: 12
SPAIN
Donostia: 2
Tenerife: 2
SWITZERLAND
Basel: 4
UNITED KINGDOM
London: 2, 3
Oxford: 3
UNITED STATES OF AMERICA
California
La Jolla: 13
Riverside: 9
Illinois
Argonne: 8
Chicago: 8
Massachusetts
Boston: 14
Cambridge: 7
New Jersey
Piscataway: 6
Princeton: 1
New York
New York: 10
Pennsylvania
Philadelphia: 8
Tennessee
Nashville: 11
Wisconsin
Madison: 13
PRESS CONTACTS…
From North America and Canada
Neda Afsarmanesh, Nature New York
Tel: +1 212 726 9231; E-mail: [email protected]
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected]
From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
From the UK/Europe/other countries not listed above
Jen Middleton, Nature London
Tel: +44 20 7843 4502; E-mail [email protected]
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