WWW.NATURE.COM/NATURE
This press release is copyright Nature. VOL.446 NO.7136 DATED 05 APRIL 2007
This press release contains:
· Summaries of newsworthy papers:
Neuroscience: A light-switch for brain cells
Planetary science: Winds of change
Microbiology: Antibiotic-resistant bacteria meet their match?
Geology: Geomagnetic data captured in crystals
Earth sciences: A salty solution
Atom spectroscopy: The great electron escape
And finally… Algorithm for group success?
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
Editorial contacts: While the best contacts for stories will always be the authors themselves, in some cases the Nature editor who handled the paper will be available for comment if an author is unobtainable. Editors are contactable via Ruth Francis on +44 20 7843 4562. Feel free to get in touch with Nature's press contacts in London, Washington and Tokyo (as listed at the end of this release) with any general editorial inquiry.
Warning: This document, and the Nature papers to which it refers, may contain information that is price sensitive (as legally defined, for example, in the UK Criminal Justice Act 1993 Part V) with respect to publicly quoted companies. Anyone dealing in securities using information contained in this document or in advanced copies of Nature’s content may be guilty of insider trading under the US Securities Exchange Act of 1934.
The Nature journals press site is at http://press.nature.com
· PDFs for the Articles, Letters, Progress articles, Review articles, Insights and Brief Communications in this issue will be available on the Nature journals press site from 1400 London time / 0900 US Eastern time on the Friday before publication.
· PDFs of News & Views, News Features, Correspondence and Commentaries will be available from 1400 London time / 0900 US Eastern time on the Monday before publication
PICTURES: While we are happy for images from Nature to be reproduced for the purposes of contemporaneous news reporting, you must also seek permission from the copyright holder (if named) or author of the research paper in question (if not).
HYPE: We take great care not to hype the papers mentioned on our press releases, but are sometimes accused of doing so. If you ever consider that a story has been hyped, please do not hesitate to contact us at [email protected], citing the specific example.
PLEASE CITE NATURE AND OUR WEBSITE www.nature.com/nature AS THE SOURCE OF THE FOLLOWING ITEMS. IF PUBLISHING ONLINE, PLEASE CARRY A HYPERLINK TO http://www.nature.com/nature
[1] Neuroscience: A light-switch for brain cells (pp 633-639; N&V)
An elegant technique using light to control the activity of brain cells is described in this week’s Nature. By expressing a light-responsive membrane protein in neurons, researchers can inhibit neural activity on a millisecond timescale.
Karl Deisseroth and colleagues introduced NpHR — a light-driven chloride pump that occurs naturally in microorganisms known as archaea — into cultured mammalian neurons and brain tissue in the laboratory. Training light pulses of a particular wavelength onto these cells effectively inhibited neural activity. This builds on the authors’ previous work using the protein ChR2 — a light-responsive channel found in algae — to optically excite nerve cells with light of a different wavelength. By simultaneously expressing both membrane proteins in the muscle cells or motor neurons of the nematode worm Caenorhabditis elegans, the authors were able to control its locomotive behaviour — the worms stopped and started muscle contractions when yellow and blue lights were shone on them.
These findings demonstrate that light-responsive proteins can be used simultaneously to permit fast, bidirectional and reversible control over living neural circuits. They can also be used in conjunction with calcium imaging techniques and, together, provide a powerful tool for studying and manipulating brain activity with high precision.
CONTACT
Karl Deisseroth (Stanford University, CA, USA)
Tel: +1 650 736 4325; E-mail: [email protected]
Michael Hausser (University College London, UK) N&V author
Tel: +44 207 679 6756; E-mail: [email protected]
[2] Planetary science: Winds of change (pp 646-649)
Variations in the radiation reflected from the surface of Mars are contributing to climate change on the planet, by causing increased dust transport and wind circulation. A study in this week’s Nature predicts that the planet has warmed by around 0.65 degrees Celsius from the 1970s to the 1990s, which may in part have caused the recent retreat of the southern polar ice cap.
The fraction of solar radiation reflected from an object is called its albedo — and on Mars, large areas on the surface show a contrast in brightness or darkness with the areas next to them, resulting in albedo patterns, which can change in appearance over time. These changes in brightness have been generally attributed to the presence of dust, but until now their effect on wind circulation and climate has not been clear.
Lori K. Fenton and colleagues present predictions from a Mars global circulation model which show that these changes are having a much larger than expected effect on climate. Large swaths of the surface have darkened over the past three decades as they were swept free of dust, leading to elevated air temperatures and increased wind stresses. This creates a positive feedback loop between dust erosion and albedo. The authors conclude that albedo variations interact with, and can in part drive, other climate-influencing processes on Mars, and should be considered as an important component in future atmospheric and climate studies of the planet.
CONTACT
Lori K. Fenton (Carl Sagan Center, NASA Ames Reserach Centre, Moffett Field, CA, USA)
Tel: +1 510 786 7199; E-mail: [email protected] or [email protected]
[3] Microbiology: Antibiotic-resistant bacteria meet their match? (pp 668-671)
Researchers may have found a way of keeping drug-resistant bacteria in check — certain combinations of antibiotics favour the growth of non-resistant strains at the expense of resistant ones. The finding, reported in this week’s Nature, may help combat the spread of these microbes, as well as shed light on microbial ecology and evolution.
Antagonistic drug combinations, in which the drugs' cumulative effects are less than when they are given separately, show such effects, say Roy Kishony and colleagues. At sublethal concentrations, a mixture of doxycycline and ciprofloxacin preferentially selects for wild-type Escherichia coli bacteria over that of a doxycyline-resistant strain in a laboratory culture.
The finding is surprising and counter-intuitive, as the use of antibiotic drugs is responsible for the generation and selection of resistant bacterial pathogen strains. But this study shows that, with the right combinations and concentrations, non-resistant bacterial strains can be selected for.
CONTACT
Roy Kishony (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 432 6390; E-mail: [email protected]
[4] Geology: Geomagnetic data captured in crystals (pp 657-660; N&V)
Researchers have used silicate crystals to determine the strength of the Earth’s geomagnetic field around 3.2 billion years ago. Their findings, revealed in this week's Nature, should help to shed light on the evolution of the Earth’s deep interior, surface environment and atmosphere.
John A. Tarduno and colleagues studied silicate crystals from well preserved igneous rocks found in South Africa’s Archaean Kaapvaal craton. The crystals contain minute magnetic inclusions, and the team calculate that 3.2 billion years ago, the Earth’s geomagnetic field strength was within fifty per cent of the present-day value. This means that there was probably a viable magnetosphere to shelter the planet from solar wind erosion at that time.
Little is known about the strength of the Earth’s geomagnetic field before 2.8 billion years ago, so the new data offer a welcome insight into the Earth’s geomagnetic history.
CONTACT
John A. Tarduno (University of Rochester, NY, USA)
Tel: +1 585 275 5713; E-mail: [email protected]
David J. Dunlop (University of Toronto, Canada) N&V author
Tel: +1 905 828 3968; E-mail: [email protected]
[5] Earth sciences: A salty solution (pp 654-656)
A new modelling study in this week's Nature offers an elegant explanation for a curious anomaly seen in the carbon and sulphur isotope records of the Early Cretaceous period.
In modern-day sediments, the rates of pyrite (iron sulphide) and carbon-based organic matter burial are positively related. But during the Early Cretaceous period, which began approximately 140 million years ago, they appear to be negatively related — a relationship that has, until now, been difficult to explain.
Ulrich G. Wortmann and Boris M. Chernyavsky show that this puzzling relationship could be due to the deposition of evaporites — mineral sediments that precipitate from water as it evaporates — on the ocean floor as South Africa and South America moved apart and the South Atlantic Ocean basin formed. The evaporites contain sulphate, so their production removed sulphate from the surrounding waters. Enough, the model suggests, to reduce significantly the rate at which organisms in marine sediments formed pyrite and broke down organic matter, thus explaining the negative relationship between the amount of pyrite and organic matter buried in marine sediments at this time.
Evaporite deposition may have had a similar effect at other times in Earth’s history, and so may explain other changes in carbon and sulphur cycling. These are important to understand because alterations in these cycles can have a direct effect on atmospheric oxygen levels.
CONTACT
Ulrich G. Wortmann (University of Toronto, Canada)
Tel: +1 416 978 7084; E-mail: [email protected]
[6] Atom spectroscopy: The great electron escape (pp 627-632; N&V)
Researchers have 'observed' electrons being stripped away from atoms by intense light fields, and report the results in this week’s Nature. The technique used should offer control over, and provide insights into, the dynamics of electrons inside atoms and molecules.
Given enough energy, electrons can ‘tunnel’ through the potential barrier that normally binds them to their nucleus, and escape. Ferenc Krausz and colleagues have now ‘seen’ this light-induced electron tunnelling happen in real time on the attosecond — that’s one billionth of one billionth of a second — timescale.
The team ionized neon atoms with ultrafast far-ultraviolet pulses, and then probed them with near-infrared pulses. From the observed spectra, they were then able to reconstruct the electron tunnelling.
CONTACT
Ferenc Krausz (Max-Planck-Institut für Quantenoptik, Garching, Germany)
Tel: +49 89 3290 5602; E-mail: [email protected]
Jonathan P. Marangos (Imperial College London, UK) N&V author
Tel: +44 20 7594 7857; E-mail: [email protected]
[7] And finally… Algorithm for group success? (pp 664-667)
Want to know how to make your clique, group or organization last? A new algorithm, published in this week’s Nature, can help you do just that.
Tamás Vicsek and colleagues studied the patterns of information exchange within two groups of individuals — collaborating scientists and mobile phone users — over time. From this, they devised an algorithm to let them study how information exchange affects group stability.
Small groups, they report, have a few strong relationships at their core. And as long as these persist, the clique remains. But the strategy doesn’t work for large communities, where change seems a good thing. Continuous change helps large groups to remain stable, and over time, nearly all members are exchanged.
The findings help shed light on the basic relationships behind community evolution, and offer insights into the fundamental differences between the dynamics of small groups and large institutions.
CONTACT
Tamás Vicsek (Eötvös Loránd University, Budapest, Hungary)
Tel: +36 1 372 2755; E-mail: [email protected]
ALSO IN THIS ISSUE…
[8] Mechanism of auxin perception by the TIR1 ubiquitin ligase (pp 640-645; N&V)
[9] Lanthanide contraction and magnetism in the heavy rare earth elements (pp 650-653)
[10] Doushantuo embryos preserved inside diapause egg cysts (pp 661-663)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 04 April 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 them on this release to avoid multiple mailings they will not appear in print on 05 April, but at a later date.***
[11] Phosphorylation of Erp1 by p90rsk is required for cytostatic factor arrest in Xenopus laevis eggs
DOI: 10.1038/nature05696
[12] A new perceptual illusion reveals mechanisms of sensory decoding
DOI: 10.1038/nature05739
[13] Template switching during break-induced replication
DOI: 10.1038/nature05723
[14] UDP acting at P2Y6 receptors is a mediator of microglial phagocytosis (N&V)
DOI: 10.1038/nature05704
[15] A direct link of the Mos–MAPKpathway to Erp1/Emi2 in meiotic arrest of Xenopus laevis eggs
DOI: 10.1038/nature05688
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.
AUSTRIA
Vienna: 6
CANADA
Toronto: 5
CHINA
Nanjing: 10
DENMARK
Aarhus: 9
FRANCE
Paris: 13
GERMANY
Bielefeld: 6
Frankfurt: 1
Garching: 6
Halle: 9
Hamburg: 6
Wurzburg: 1
JAPAN
Fukuoka: 14, 15
Saitama: 15
Tokyo: 14
Yamanashi: 14
Yokohama: 11
NETHERLANDS
Amsterdam: 6
RUSSIA
Moscow: 6
SOUTH AFRICA
Durban: 4
THAILAND
Bangkok: 9
UNITED KINGDOM
Cambridge: 8
Coventry: 9
Warrington: 9
UNITED STATES OF AMERICA
Arizona
Flagstaff: 22
California
Moffett Field: 2
Stanford: 1
Indiana
Bloomington: 8
Maryland
Bethesda: 14
Massachusetts
Boston: 3
Cambridge: 3
New York
New York: 12, 13
Rochester: 4
Washington
Seattle: 8
PRESS CONTACTS…
For North America and Canada
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected]
For Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
For the UK/Europe/other countries not listed above
Helen Jamison, Nature London
Tel: +44 20 7843 4658; E-mail [email protected]
About Nature Publishing Group
Nature Publishing Group (NPG) is a division of Macmillan Publishers Ltd, dedicated to serving the academic, professional scientific and medical communities. NPG's flagship title, Nature, was first published in 1869. Other publications include Nature research journals, Nature Reviews, Nature Clinical Practice and a range of prestigious academic journals including society-owned publications. NPG also provides news content through [email protected] and scientific career information through Naturejobs.
NPG is a global company with headquarters in London and offices in New York, San Francisco, Washington DC, Boston, Tokyo, Paris, Munich, Hong Kong, Melbourne, Delhi, Mexico City and Basingstoke. For more information, please go to <www.nature.com>
