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This press release is copyright Nature. VOL.440 NO.7087 DATED 20 April 2006
This press release contains:
* Summaries of newsworthy papers:
- Glaciology: Antarctic plumbing revealed
- Medicine: Metabolic phenotype predicts drug response
- Climate: Very high climate sensitivity looks unlikely
- Genetics: Keeping stem cells in check
- Evolution: Snake-hipped fossil shows how earliest snakes used their legs
- Social evolution: how exactly did we all start cooperating?
- Astronomy: Where's all that light coming from?
- Evolution: Evolutionary pathways lead to same destination
- And finally… Invisible skeleton
* Mention of papers to be published at the same time with the same embargo
* Geographical listing of authors
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[1] Glaciology: Antarctic plumbing revealed (pp1033-1036; N&V)
Lakes underneath the surface of the Antarctic ice sheets may be connected to one another by a plumbing system beneath the ice, according to Martin Siegert and his colleagues in Nature this week.
During satellite studies of lakes under the East Antarctic Ice Sheet, the team saw the ice surface lower by about 3 metres over a subglacial lake and bulge at two other subglacial lakes some 290 kilometres away. They believe these changes in ice elevation may be accounted for by the flow of around 1.8 cubic kilometres of water over a 16-month period beneath the 3-kilometre-thick ice sheet.
These changes in ice elevation may be accounted for by the movement of around 1.8 cubic kilometres of water over a 16-month period: a flow that, at its heaviest, was equal to about threequarters of the discharge of London's River Thames. These subglacial lakes in Antarctica were previously thought to be relatively isolated and long-lived. Siegert argues that they may be regularly flushed in response to build-ups in water pressure. Some flows might even carry the lake water all the way to the coast of Antarctica, allowing the lakes to discharge into the sea. The rapid transfer of water between subglacial lakes would diminish the likelihood that any single lake would contain an isolated ecosystem and also indicates that contamination of one lake by drilling may result in widespread contamination.
CONTACT
Martin Siegert (University of Bristol, UK)
Tel: +44 117 928 8902; E-mail: [email protected]
Garry Clarke (University of British Columbia, Vancouver, Canada)
Tel: +1 604 822 3602; E-mail: [email protected]
[2] Medicine: Metabolic phenotype predicts drug response (pp1073-1077)
In this week's Nature, a team from Europe proposes a new way to personalize drug therapy based on a patient's metabolic phenotype. They show that this method can predict damage caused by high-dose paracetamol in rats.
Many biomedical researchers are excited about pharmacogenomics, in which drug treatment is tailored to a patient's genetic profile. But the utility of this method may be limited, partly because it does not take into account how quickly a person reacts to and breaks down the drug, which itself is influenced by genes, diet, gut bacteria, age, disease and other drugs in the body.
Jeremy Nicholson and colleagues propose an alternative approach called 'pharmaco-metabonomics'. They used nuclear magnetic resonance spectroscopy to analyse the metabolites in rat urine, and found that certain metabolic signatures can be used to predict the severity of liver damage caused by a toxic dose of paracetamol, perhaps because they indicate how well equipped the body is to protect itself from the drug.
The proof-of-principle experiment suggests that this approach might be used to screen people and decide which drugs they can safely take, and at what doses. It might also find a use predicting people's responses to all kinds of other medical, dietary or physiological challenges.
CONTACT
Jeremy Nicholson (Imperial College London, UK)
Tel: +44 20 7594 3195; E-mail: [email protected]
[3] Climate: Very high climate sensitivity looks unlikely (pp1029-1032)
A reconstruction of the Northern Hemisphere's climate over the past 700 years suggests that our planet's temperature may be less sensitive to carbon dioxide increases than some scientists had predicted.
The temperature change induced by a doubling of the carbon dioxide concentration in the atmosphere is known as 'climate sensitivity'. Although the generally accepted value for this parameter ranges from 1.5 to 4.5 degrees Celsius, some estimates from observational studies have estimated that the temperature change may be as high as 9 degrees Celsius.
But in this week's Nature, Gabriele Hegerl and colleagues report that climate reconstructions using data extending back some seven centuries imply that the sensitivity is unlikely to be above 6.2 degrees Celsius, substantially reducing the probability of very high climate sensitivity.
CONTACT
Gabriele Hegerl (Duke University, Durham, NC, USA)
Tel: +1 919 684 6167; E-mail: [email protected]
[4] Genetics: Keeping stem cells in check (AOP)
DOI: 10.1038/nature04733
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 19 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 it on this release to avoid multiple mailings it will not appear in print on 20 April, but at a later date.***
A group of proteins has been shown to help hold the reins on embryonic stem (ES) cell differentiation. ES cells are unique in their ability to self-renew while maintaining the ability to develop into virtually all adult cell types. Researchers report online this week in Nature that Polycomb group (PcG) proteins suppress the activation of many genes involved in cell developmental pathways.
Specifically, Rudolph Jaenisch and colleagues use a genome-wide location analysis in mouse ES cells to determine the genomic sites occupied by PcG protein complexes. They find that these complexes occupy the regulatory regions of a large number of target genes involved in cell differentiation - genes whose expression is repressed in undifferentiated ES cells. However, these genes are activated when the ES cells are induced to differentiate, and so it seems that the role of the PcG complexes is to keep their expression (and thus cell differentiation) in check in undifferentiated cells. When PcG complexes are disrupted in ES cells, expression of the target genes becomes activated and the cells tend to differentiate.
This research continues to build on our understanding of how ES cells are maintained and their potential as a therapeutic for many diseases.
CONTACT
Rudolph Jaenisch (Massaschusetts Institute of Technology, Cambridge, MA, USA)
Tel: +1 617 258 5186; E-mail: [email protected]
[5] Evolution: Snake-hipped fossil shows how earliest snakes used their legs (pp1037-1040)
Snakes probably evolved on land rather than slinking up out of the sea, suggests a fossil that represents the very dawn of this group. The snake, found in Patagonia in Argentina, is the most primitive snake ever found and the only one ever discovered with hips.
The discovery suggests that the very earliest snakes were burrowing land animals, rather than marine animals that later crawled onto land, say Sebastián Apesteguía and Hussam Zaher, who report the find in this week's Nature. The fossil's 'hips' - a skeletal component called the sacral region that links the hindlimbs to the backbone - show that the snake's legs would have been adapted to digging or crawling.
The newly discovered species lived in the Late Cretaceous period more than 65 million years ago. Later snakes subsequently lost their hips and then their legs as they became more specialized and gradually adopted their current range of aquatic and terrestrial lifestyles.
CONTACT
Hussam Zaher (Museu de Zoologia da Universidade de Sao Paulo, SP, Brazil)
Tel: +55 11 61 65 80 90; E-mail: [email protected]
[6] Social evolution: how exactly did we all start cooperating? (pp1045-1049)
Human societies are notable for the prevalence of cooperation, but the origins of this behaviour are confusing, especially given the potential benefits for anyone prepared to take advantage of others' kindness. Traditionally, this has been investigated using simple 'game theory' tests in which people or computers are given a simple choice of different strategies, such as cheating or helping a fellow player. But these models lack the sophistication of the real world.
A new, more sophisticated computer model now shows that a range of cooperative strategies can arise spontaneously, as long as people are free to see whether others are similarly imbued with community spirit. Agents in the computer model occupy a matrix of virtual squares, and can 'choose' either to rest, eat, reproduce or attack a neighbour.
A range of different strategies emerges, say the model's developers Mikhail Burtsev and Peter Turchin in this week's Nature. Alongside the aggressive 'hawks' and docile 'doves' seen in previous game-theory exercises, other options arise, such as 'ravens', which fight with others but get along fine with their own kind, and 'starlings', which clump together and share resources in the knowledge that their strength of numbers allows them to repel invaders.
CONTACT
Mikhail Burtsev (Keldysh Institute of Applied Mathematics of RAS, Moscow, Russia)
Tel: +7 903 561 4149; E-mail: [email protected]
Commentary: Learning from Chernobyl (pp933-934) (pp982-983)
As the 20-year anniversary of Chernobyl approaches, a Commentary and Special News Report in Nature this week investigate the health effects of radioactive fallout, particularly in the light of a United Nations (UN) report assessing the effects of the disaster.
Last year's prediction by the UN Chernobyl Forum of a maximum of 9,000 radiation-related deaths in regions heavily contaminated by Chernobyl is too reassuring, given the massive uncertainties, argue Dillwyn Williams and Keith Baverstock. The lesson of the atomic bombs in Nagasaki and Hiroshima is that 20 years is too soon to be able to predict all the consequences of fallout.
Although the type of radiation exposure was different in Japan, the Radiation Effects Research Foundation set up to study the bombs' legacy should be a model for coordinated monitoring of possible health consequences, they argue. At the very least, say the authors, there should be comprehensive studies on the hundreds of thousands of people in the most affected areas of Belarus, Ukraine and Russia. Williams and Baverstock believe that unless a full and independent study of the consequences of Chernobyl is established, public mistrust of the nuclear industry will continue.
In a Special News Report on the same topic, Mark Peplow further explores the arguments over the disaster's death toll. Scientists cited in the UN report are concerned about how their figures are presented. They argue that the true cost of the disaster will not be known for decades, if ever. The report investigates how these figures were reached, and what further monitoring should be done before further predictions can be made.
CONTACT
Dillwyn Williams (Strangeways Research Laboratories, Cambridge, UK)
Tel: +44 1223 740 180; E-mail: [email protected]
[7] & [8] Cell biology: Regular recycling saves lives (AOP)
DOI: 10.1038/nature04723
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 19 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 20 April, but at a later date.***
The process of protein degradation and clearance of cellular components may be more important in maintaining the nervous system and keeping neurodegeneration at bay than was previously understood, according to two papers to be published online by Nature this week.
Autophagy - protein degradation and recycling of cellular components - is important for the normal growth and development of a cell. Two research teams now show that inhibiting this process in mouse brain cells results in neurodegeneration and early death.
In the first paper, Keiji Tanaka and colleagues create mice with a neural-cell-specific deficiency in the Atg7 gene, which encodes a key enzyme essential for autophagosome formation. These mice exhibited a reduction in coordinated movement, and a massive buildup of proteins and loss of neurons in the cerebral and cerebellar cortices, which led to a premature death 28 weeks after birth. In the second paper, Noboru Mizushima and colleagues knocked out the Atg5 gene. These mice also developed progressive motor-function impairment and tremors, which were accompanied by the accumulation of cytoplasmic protein-containing inclusion bodies in neurons. Both papers show that the continual clearance of cellular components is essential for maintaining neuronal health and opens new avenues of research to tackle neurodegenerative disease.
CONTACT
Keiji Tanaka (The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan)
Tel: +81 3 3823 2237; E-mail: [email protected] Paper [7]
Noboru Mizushima (The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan)
Tel: +81 3 4463 7590; E-mail: [email protected] Paper [8]
[9] Astronomy: Where's all that light coming from? (pp1018-1021; N&V)
Looking out into the vastness of space, astronomers can see plenty of light in the darkness.
Until now they have been unsure how much is due to local starlight and what comes from the early Universe. In this week’s Nature Luigi Costamante and collaborators have found a way to cut through these difficulties to identify the major sources of near-infrared light by measuring this background light indirectly.
The sum of all this light is called the extragalactic background light (EBL). Some comes from the observable stars in galaxies beyond our own - that is, from our 'local' neighbourhood - but some comes from very ancient objects, such as the first stars ever formed.
The problem is made harder by the fact that dust in our Solar System radiates light at the same wavelengths - in the infrared - at which the EBL is brightest, flooding the EBL signal with 'light pollution'.
The team detected the gamma rays coming from two blazars, a class of galaxies in which very violent processes produce intense high-energy radiation. These gamma rays are slightly dimmed by the time they reach the Earth, thanks to a process like Compton scattering that involves the gamma rays bouncing off photons of infrared light on their journey. The researchers are able to estimate the minimum extent of this dimming by considering the maximum plausible brightness of the blazars, which enables them to calculate the infrared EBL between us and the blazars.
They find that this contribution is close to the lower limit of the estimate of all the near-infrared light produced by the intervening, 'local' galaxies. In other words, that's where most of the EBL comes from - there’s not much coming from the earliest stars.
CONTACT
Luigi Costamante (Max Planck Institut fuer Kernphysik Astrophysics, Heidelberg, Germany)
Tel: +49 622 151 6470; E-mail: [email protected]
Piero Madau (University of California, Santa Cruz, CA, USA)
Tel: +1 831 459 3839; E-mail: [email protected]
[10] Evolution: Evolutionary pathways lead to same destination (pp1050-1053; N&V)
A long-standing issue in evolutionary biology is whether a trait is constrained to evolve via the same genetic path, or whether there can be more than one route to a trait. A study in this week's Nature suggests that the latter can occur.
Sean Carroll and his colleagues show that a wing spot of dark pigment involved in male courtship display has been gained at least twice and lost at least five times in different species of Drosophila flies as they evolved from an unspotted common ancestor.
By detailed genetic analysis, the team shows that wing spots arose in two different lineages using the same yellow pigmentation gene, but that each lineage co-opted different regulatory gene sequences to do so - in other words, evolution took different routes to the same destination. The mechanism is an example of the sort of evolutionary tinkering with available genetic components envisioned by Francois Jacob three decades ago, the authors say.
CONTACT
Sean Carroll (University of Wisconsin-Madison, Madison, WI, USA)
Tel: +1 608 262 6191; E-mail: [email protected]
Gregory Wray (Duke Unversity, Durham, NC, USA)
Tel: +1 919 684 6696; E-mail: [email protected]
[11] And finally… Invisible skeleton (p1055)
Scientists have discovered that the land crab Gecarcinus lateralis uses a novel 'skeleton' of gas and water to prop itself up during moulting. Reported in a Brief Communication in this week's Nature, the study describes how these land crabs support themselves without the luxury of an aquatic environment.
Crabs have hard exoskeletons, which have to be shed in order to allow them to grow. Moulting takes place when a new exoskeleton starts growing beneath the old one. Meanwhile, the crabs have to inflate their bodies so that the new exoskeleton hardens to a size larger than that of their old armour. Unlike their aquatic counterparts, which rely on a water-based, hydrostatic system, land crabs have the dilemma of how to support their soft bodies during this time and in a situation where water is limited. Jennifer Taylor and William Kier now demonstrate that the land crab G. lateralis makes use of compressed gas in its gut as a booster to increase the rigidity of its body.
The authors suggest that this adaptation may not only be a result of low water availability but also that it may have been crucial for early crustaceans learning to live on land.
CONTACT
Jennifer Taylor (University of North Carolina, Chapel Hill, NC, USA)
Tel: +1 919 843 5868; E-mail: [email protected]
ALSO IN THIS ISSUE…
[12] Crystal structure of an Hsp90- nucleotide-p23/Sba1 closed chaperone complex (pp1077-1012)
[13] Experimental determination of entanglement with a single measurement (pp1022-1024)
[14] Polarons and confinement of electronic motion to two dimensions in a layered manganite (pp1025-1028)
[15] DNA sequence of human chromosome 17 and analysis of rearrangement in the human lineage (pp1045-1049)
[16] Unique features of action potential initiation in cortical neurons (pp1060-1063; N&V)
[17] Enhanced bacterial clearance and sepsis resistance in caspase-12-deficient mice (pp1064-1068)
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
Buenos Aires: 5
ARMENIA
Yerevan: 9
BRAZIL
Rio de Janeiro: 13
Sao Paulo: 5
CANADA
Montreal: 15, 17
FRANCE
Amboise: 2
Gif sur Yvette: 12
Grenoble: 9
Meudon: 9
Montpellier: 9
Paris: 9
Toulouse: 9
GERMANY
Berlin: 9
Bochum: 16
Dresden: 13
Gottingen: 16
Hamburg: 9
Heidelberg: 9
IRELAND
Dublin: 9
JAPAN
Fukushima: 7
Kawaguchi: 8
Nagahama: 8
Niigata: 8
Okazaki: 8
Osaka: 7
Tsukuba: 14
Tokyo: 8, 7
Yokohoma: 8
RUSSIA
Moscow: 6, 16
SOUTH AFRICA
Potchefstroom: 9
SPAIN
Madrid: 4
SWITZERLAND
Villigen: 14
THE NETHERLANDS
Amsterdam: 4
UNITED KINGDOM
Bristol: 1
Cambridge: 1, 15, 10
Durham: 9
Edinburgh: 1
Kent: 2
London: 12, 14, 1, 15, 2
Oxford: 3
Sheffield: 12
UNITED STATES OF AMERICA
California
Los Angeles: 4
Oakland: 15
San Diego: 17
Connecticut
Storrs: 6
Massachusetts
Cambridge: 13, 15, 10, 4
Michigan
Ann Arbor: 2
New Jersey
Murray Hill: 14
New York
New York: 15
Stony brook: 10
North Carolina
Chapel Hill: 11
Durham: 3
Tennessee
Memphis: 17
Texas
Houston: 15
Wisconsin
Madison: 15, 10
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
Rinoko Asami, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
For the UK/Europe/other countries not listed above
Ruth Francis, Nature London
Tel: +44 20 7843 4562; E-mail [email protected]
Victoria Picknell, Nature London
Tel: +44 20 7843 4502; E-mail: [email protected]
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