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This press release is copyright Nature.
VOL.442 NO.7101 DATED 27 JULY 2006
This press release contains:
* Summaries of newsworthy papers:
Cell biology: Electrical signalling genes identified
Planetary science: Methane storms on Titan
Microbiology: Acid-loving microbes thrive in deep-sea heat baths
Geology: Faulting the ocean floor
Solid-state physics: Spin doctors leave their mark/produce material benefit
Neuroscience: Choosing Face
And finally… How fishy fins arise
* Mention of papers to be published at the same time with the same embargo
* Geographical listing of authors
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[1] Cell biology: Electrical signalling genes identified (pp 444-447)
Two of the genes essential to wound healing mediated by endogenous electrical currents are revealed for the first time in Nature this week. Scientists have visualized wound healing guided by an electric field (EF) and identified the genes governing this process as PI(3)Kgamma and PTEN.
Previous research has shown that damage to epithelial tissue - for example, skin - results in strong, directional ion flow and generates an internal EF. These EFs are thought to guide moving cells, by a process known as electrotaxis, in order to heal the wound. However, direct evidence of such electrically guided cell movement has been lacking until now.
A team of researchers led by Min Zhao and Josef Penninger used time-lapse photography to visualize electrotaxis in animal cell and tissue cultures. They found that wounds may close faster or be driven open, depending on the direction of externally applied electrical signals similar in strength to those occurring naturally. The authors also identified the genes that control electrotaxis as PI(3)Kgamma and PTEN, and propose that electrical signals may be used in the future to direct cell growth during wound healing in cell and tissue engineering.
CONTACT
Min Zhao (University of Aberdeen, UK)
Tel: +44 1224 555732; E-mail: [email protected]
[2] & [3] Planetary science: Methane storms on Titan (pp 428-431; 432-435; N&V)
Methane rain - ranging from drizzle to intense storms - falls upon the surface of Titan, according to two studies, one theoretical and one based on data from the Huygens probe that landed on Titan around 18 months ago.
In this week's Nature, R. Hueso and A. Sánchez-Lavega report that the strongest storms will occur when methane humidity in the middle atmosphere tops 80%, producing updrafts as fast as 72 kilometres per hour that create thick clouds at altitudes of about 30 kilometres in a matter of hours.
Hydrocarbon raindrops up to a centimetre across can then fall, delivering up to 110 kilograms of liquid on each square metre of Titan's surface below. The Cassini probe, currently in orbit around Saturn, should be able to spot these sudden storms and observe the cooling effect that their rain has on the moon's surface, the astronomers predict.
A related paper in the same issue of Nature by Tetsuya Tokano and colleagues uses the data obtained by the Huygens lander to investigate how the methane behaves around the moon and its effects on weather and surface geology. They show thin layers of cloud - an upper methane ice cloud and a lower, liquid methane-nitrogen one. The lower layer produces a drizzle that wets the moon’s surface and actively shapes its geology - despite low levels of rainfall, the drizzle keeps the surface wet. The researchers argue that it is this drizzle and not the clouds that shape Titan’s methane cycle.
CONTACT
Ricardo Hueso (Universidad del Pais Vasco, Bilbao, Spain) Author paper [2]
Tel: +34 94601 4269 wk; E-mail: [email protected]
Tetsuya Tokano (Cologne University, Germany) Author paper [3]
Tel: +49 221 470 4489; E-mail: [email protected]
Caitlin A Griffith (University of Arizona, Tucson, AZ, USA) N&V author
Tel: +1 520 626 3806; E-mail: [email protected]
[4] Microbiology: Acid-loving microbes thrive in deep-sea heat baths (pp 444-447)
The water around deep-sea hydrothermal vents is hot and acidic, which makes it surprising that no microbial species had so far been isolated that takes advantage of these conditions. But now researchers have successfully grown the first such specialist microbe, taken from a vent on the Pacific Ocean floor, in the laboratory.
This 'thermoacidophilic' microbe, belonging to the DHVE2 group of Archaea, is described by Anna-Louise Reysenbach and her colleagues in this week’s Nature. They cultivated the organism and found that it thrives at acidic pH values between 3.3 and 5.8, and at temperatures between 55 and 75 degrees Celsius - enough to kill off most organisms.
What's more, the researchers discovered that this isolate represents around 15% of archaeal species present at these hydrothermal vents, suggesting that thermoacidophiles may be the most important players in recycling iron and sulphur in the ocean depths.
CONTACT
Anna-Louise Reysenbach (Portland State University, OR, USA)
Tel: +1 503 725 3864; E-mail: [email protected]
[5] Geology: Faulting the ocean floor (pp 440-443)
New insights into the generation and evolution of oceanic crust are published this week in Nature. The survey, of a segment of the Mid-Atlantic Ridge, looks at the topography of active faults extending from the ridge axis, whereas previous studies have been based mainly on inactive sites further away.
The Mid-Atlantic Ridge is characterized by spreading along low-angle detachment faults, exposing lower-crustal and upper-mantle rocks as they well up through the centre. The nature of this type of faulting has until recently been difficult to understand owing to the lack of observations of active detachment faults at different stages of growth.
Deborah Smith and colleagues used data from a new survey of the ridge along with previously recorded maps and seismicity to reveal how these faults begin and evolve, giving a clearer picture of the whole process of sea-floor spreading. The data from the survey, together with the seismic observations, suggest that a 75-km-long chain of detachment faults on the western side of the valley is still active.
They conclude that this type of faulting is more important in the generation of oceanic crust at the Mid-Atlantic Ridge than was previously thought. The processes identified in this area may help researchers understand other regions of similar faulting in oceans and also on land, where erosion makes interpretation difficult.
CONTACT
Deborah K Smith (Woods Hole Oceanographic Institute, MA, USA)
Tel: +1 508 289 2472; E-mail: [email protected]
[6] Solid-state physics: Spin doctors leave their mark (pp 436-439; N&V)
Spintronics, a potential new form of electronics which exploits a quantum property of electrons called spin, needs new materials that fill the same kind of role as semiconductors in conventional silicon electronics. In this week’s Nature, Ali Yazdani and colleagues report on a version of such a material tailored atom by atom, which has allowed them to figure out how such materials can be grown on a larger scale with the properties needed for spintronic devices.
The researchers studied a material called manganese-doped gallium arsenide (Ga1-xMnxAs), which has been identified previously as a candidate spintronic fabric. Its key characteristic is that the manganese atoms, which are sparsely distributed throughout the gallium arsenide matrix, are magnetic, and can interact with one another to form a magnetically ordered state that can be used to manipulate the spins of electrons.
But this magnetic state forms only when the substance is cooled well below room temperature. Yazdani and colleagues investigate how each manganese (Mn) atom interacts magnetically with those nearby, by using a device called the scanning tunnelling microscope to position individual Mn atoms within a thin film of gallium arsenide (GaAs). Voltage pulses from the microscope’s needle-like tip fix a Mn atom into the film at a specific position.
This allows the researchers to see that the interactions between neighbouring Mn atoms is stronger in one particular direction, corresponding to the alignment of rows of Ga and As atoms in the crystalline film, than in others. They say that growing Ga1-xMnxAs in a way that creates neighbouring Mn atoms along this direction might raise the temperature at which it becomes magnetically ordered.
CONTACT
Ali Yazdani (Princeton University, NJ, USA)
Tel: +1 609 258 4390; E-mail: [email protected]
Nitin Samarth (Penn State University, University Park, PA, USA)
Tel: +1 814 863 0136; E-mail: [email protected]
[7] Neuroscience: Choosing Face (AOP)
DOI: 10.1038/nature04982
***This paper will be published electronically on Nature's website on 26 July 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 27 July, but at a later date.***
The role of particular neurons in a region of monkeys’ brains known to be important for object recognition is more clearly established by a study appearing online in Nature this week. The research shows that artificially activating these nerve cells biases the monkey’s choices in face categorization tasks.
Hossein Esteky and colleagues studied face perception in two adult monkeys (Macaca mulatta) trained to complete a task in which they had to judge whether noisy visual images, some of which were faces, belonged to “face” or “non-face” categories. The researchers electrically stimulated clusters of neurons in the inferotemporal cortex that were shown to respond selectively to faces, with the result that the decisions made by the monkeys were biased towards the face category. The authors report that this effect depended upon the size of the brain area stimulated and the exact time at which stimulation occurred.
The precise role of face-selective neurons in behaviour has been under debate. The authors suggest that their research, at very high spatial resolution, establishes a causal link between the activity of face-selective neurons and face perception.
CONTACT
Hossein Esteky (Institute for Studies in Theoretical Physics and Mathematics, Tehran, Iran)
Tel: +98 21 2229 4035; E-mail: [email protected]
[8] And finally… How fishy fins arise (AOP)
DOI: 10.1038/nature04984
***This paper will be published electronically on Nature's website on 26 July 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 27 July, but at a later date.***
From the scariest shark to the tiniest tiddler, all fish use the same genetic template to produce their different styles of fins, biologists have discovered. Even lampreys, which have their own distinctive look, share the same pattern of gene expression that gives rise to their primitive fins - suggesting that this template was in place long before the different fish groups began to evolve and diverge.
In a paper appearing online in Nature, Martin Cohn and his colleagues show that median fins - which run along the centre line of a fish's back and belly - arise from the same 'finfold'. This finfold is defined by the presence of cells expressing genes called Hoxd and Tbx18, which help to dictate where fins should develop.
What's more, the pattern of cells in which these genes are expressed also determines where the symmetrical pairs of fins on the animals' sides emerge. This suggests that although lateral and median fins appear to develop in different ways, they use the same genetic cues to specify their positions. The fact that lampreys, a primitive 'living fossil' species, also adhere to this template suggests that this pattern may predate fish themselves.
CONTACT
Martin Cohn (University of Florida, Gainesville, FL, USA)
Tel: +1 352 392 8738; E-mail: [email protected]
ALSO IN THIS ISSUE…
[9] Snapshots of tRNA sulphuration via an adenylated intermediate (pp 419-424)
[10] A low fraction of nitrogen in molecular form in a dark cloud (pp 425-427)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 26 July 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 27 July, but at a later date.***
[11] The nitrate/proton antiporter AtCLCa mediates nitrate accumulation in plant vacuoles
DOI: 10.1038/nature05013
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: 1
CANADA
Guelph: 4
FRANCE
Gif-sur-Yvette: 11
Meudon: 3
Paris: 3, 5, 11
GERMANY
Cologne: 3
IRAN
Tehran: 7
ITALY
Padua: 3
JAPAN
Akita: 1
Kanagawa: 9
Saitama: 9
Tokyo: 9
Yokohama: 9
SPAIN
Bilbao: 2
THE NETHERLANDS
Texel: 4
UNITED KINGDOM
Aberdeen: 1
Leeds: 5
UNITED STATES OF AMERICA
California
Moffett Field: 3
San Francisco: 1
Florida
Gainesville: 8
Illinois
Urbana: 1, 6
Iowa
Iowa City: 6
Maryland
Baltimore: 1
Greenbelt: 3
Massachusetts
Cambridge: 10
Woods Hole: 4, 5
Michigan
Ann Arbor: 3, 10
New Hampshire
Durham: 4
New Jersey
Princeton: 6
Oregon
Portland: 4
Virginia
Reston: 4
PRESS CONTACTS…
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Tel: +1 202 737 2355; E-mail: [email protected] <mailto:[email protected]>
For Japan, Korea, China, Singapore and Taiwan
Rinoko Asami, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected] <mailto:[email protected]>
For the UK/Europe/other countries not listed above
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Tel: +44 20 7843 4658; E-mail [email protected] <mailto:[email protected]>
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