Summaries of newsworthy papers include Moonlets create waves around Saturn, Neuroscience: The future’s bright, Cancer: Host of new genes spotted, Explosive spectrometry, Developmental biology: The eyes have it, Physics: See how they run, Auxin’s roots, Nuclear physics: Extending the drip line and Lévy flights called into question
This press release is copyright Nature.
VOL.449 NO.7165 DATED 25 OCTOBER 2007
This press release contains:
· Summaries of newsworthy papers:
Planetary science: Moonlets create waves around Saturn
Climate policy: Time to ditch Kyoto
Neuroscience: The future’s bright
Cancer: Host of new genes spotted
Chemistry: Explosive spectrometry
Developmental biology: The eyes have it
Physics: See how they run
Plant biology: Auxin’s roots
Nuclear physics: Extending the drip line
And finally… Lévy flights called into question
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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 Planetary science: Moonlets create waves around Saturn (pp 1019-1021)
Wavelike disturbances in one of Saturn’s rings reported in this week’s Nature provide evidence for the ring system’s origins.
The wavelike features are the wakes of little moonlets orbiting in Saturn’s A ring, in a narrow band 130,000 kilometres from the planet. Gravitational forces from the boulder-sized bodies perturb the surrounding ring material, creating the waves observed by Miodrag Sremčević and colleagues. These moonlets must be remnants of a larger moon, rather than having a co-genetic origin with Saturn. This supports the theory that the rings formed from large icy moons that subsequently broke into smaller pieces over a long period of time.
Miodrag Sremčević (University of Colorado, Boulder, CO, USA)
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Climate policy: Time to ditch Kyoto
The Kyoto Protocol has failed in several ways, argue Gwyn Prins and Steve Rayner in their Commentary in this week's Nature, and not just in its failure to deliver emissions cuts. The fundamental failing is that it is the wrong tool for the job. Prins and Rayner are concerned that climate policy after 2012 — when the Protocol expires — risks repeating the same mistake if a 'bigger' version of Kyoto with more stringent targets and timetables is negotiated. Instead the attendees at the Bali conference in December need to radically rethink climate policy.
If Kyoto is a bad investment, then the rational thing to do is cut our losses. To help climate policymakers wipe the slate clean and start again, the authors suggest five elements that they think should be central to the looming round of climate negotiations. These include focusing emissions cuts on the biggest polluters, a bottom-up approach to emissions trading, massively increasing spending on clean-energy technologies and on adapting to the unavoidable consequences of climate change.
Gwyn Prins (LSE, London, UK)
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Steve Rayner (University of Oxford, UK)
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 Neuroscience: The future’s bright
***This paper will be published electronically on Nature's website on 24 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 25 October, but at a later date.***
As human beings, we tend to expect to live longer and be healthier than average, whereas we might underestimate our likelihood of getting divorced. Researchers have now linked this tendency for future optimism to activity in a small network of areas in the brain, and report their findings in this week’s Nature.
Optimism for the future is a common human trait. We often expect positive events to occur without any direct evidence to support these expectations. In the current study, Elizabeth A. Phelps and colleagues used functional magnetic resonance imaging (fMRI) to examine how the brain generates this optimism bias. They find that when individuals imagine positive future events relative to negative ones, enhanced activation occurs in the amygdala and rostral anterior cingulate cortex — brain areas whose function may be disrupted in depression. Activation levels in these areas are also found to correlate with individual tendencies towards optimism.
This study highlights the brain mechanisms underlying our inclination to engage in the projection of future positive events. The authors suggest it might also provide insight into those mechanisms underlying depression, which has been related to pessimism.
Elizabeth A. Phelps (New York University, NY, USA)
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 Cancer: Host of new genes spotted (pp 1073-1077)
Scientists have uncovered a complex network of genes involved in the conversion of normal cells to cancerous ones — potentially opening up a range of new strategies for developing drugs to tackle the disease.
The research, described in this week's Nature by Michael Green and his colleagues, investigates the changes that are needed to make cells cancerous. Cancer cells’ runaway growth arises partly from the ‘silencing’ of certain genes. In this study, cultured cells that have the same genetic changes as cancer cells in the body were screened for genes necessary to silence another gene Fas, which in healthy tissues ensures that cells die off when necessary, rather than growing out of control, and is silenced by Ras. They identified 28 genes, termed 'Ras epigenetic silencing factors', with a range of different functions; these genes comprise a common pathway that suppresses expression of Fas.
Michael Green (University of Massachusetts Medical School, Worcester, MA, USA)
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 Chemistry: Explosive spectrometry (pp 1033-1036)
A new and sensitive method of analysing blood, urine and single cells is presented in Nature this week. Gary Siuzdak and colleagues hope that this could be developed for biomedical applications such as fundamental studies on single cells.
Their method involves ‘initiator’ molecules that violently erupt when targeted by a laser or ion beam. A surface specially prepared for mass spectrometry is used and the initiator molecules release and ionize intact molecules on the surface so they are ready for detection.
The new method is capable of detecting metabolites such as codeine in urine at extremely low levels and the researchers hope that this technique can be developed for use in pharmacokinetics and drug localization in tissue.
Gary Siuzdak (The Scripps Research Institute, La Jolla, CA, USA)
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 Developmental biology: The eyes have it (pp 1058-1062)
A new mechanism crucial to eye development is identified in a study in this week’s Nature. The report suggests that signalling pathways mediated by purine — a nitrogenous base — might trigger the genes necessary to make the eye.
Understanding the signalling pathways that initiate organ development is of fundamental importance to medicine. Nicholas Dale and colleagues studied the pathways involved in eye development in the frog Xenopus laevis. A network of transcription factors — known as eye field transcription factors — underlies eye development in vertebrates and invertebrates, but the mechanism controlling their expression is poorly understood. The authors here report that purine-mediated signalling triggers the expression of eye field transcription factors, and thus eye development.
Dale and colleagues suggest that the role of purine-mediated signalling pathways might be widely conserved across species, because alterations to the human equivalent of an enzyme involved in these pathways cause severe head and eye defects.
Nicholas Dale (University of Warwick, Coventry, UK)
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 Physics: See how they run (pp 1029-1032; N&V)
The speed at which an electron moves across and then leaves a crystal that is hit with light is dependent on whether it started off tightly bound to one atom, or was held in an orbital containing several atoms, F. Krausz and colleagues report in Nature this week.
Electrons move in solids with very high speeds, swishing between atomic layers and across interfaces within tens to hundreds of attoseconds—billionths of a billionth of a second. But Krausz and colleagues have kept pace: they demonstrate that when exposing a tungsten crystal to intense light, the travel times of electron times within the crystal can differ by 110 attoseconds, depending on their starting position.
The researchers believe that this ability to experimentally probe fundamental aspects of electron behaviour in solids could help in the development of modern electronics and information processing technologies, all of which rely on the control of electron transport in solids.
F. Krausz (Max PIanck für Quantenoptik, Garching, Germany)
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David M Villeneuve (National Research Council of Canada, Ottawa, Ontario, Canada)
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 &  Plant biology: Auxin’s roots (pp 1008-1013, N&V; 1053-1057)
The hormone auxin is dependent on a simple regulatory factor to control the pattern of root development in plants. An article published in this week’s Nature explains how it settles in the correct location in the roots, the auxin maximum, and demonstrates what happens if this process is interfered with. A related paper looks downstream at genes that affect whether cells divide or differentiate during plant development.
Auxin has been linked to virtually every developmental process in plants. It accumulates at a specific point, the auxin maximum. If the maximum or associated gradients are disturbed root patterns are affected. Ben Scheres and colleagues use computer modelling and experiments to investigate how this location is defined, and show that PIN proteins are responsible for regulating auxin’s transport in and across cells. The authors go on to demonstrate how the maximum is generated by the pattern of these PIN proteins, and what happens when they are disturbed.
In a second paper, the same group reveals how PLETHORA (PLT) proteins, principal factors in root cell development, affect this development. The concentration of PLT proteins affects their function, with high numbers creating stem cells, medium numbers promoting cell division and low numbers generating differentiation in root cells. This is the first evidence for this kind of gradient action in plant development.
Ben Scheres (Utrecht University, Netherlands)
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Bruce Veit (AgResearch,Palmerston North, New Zealand)
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 Nuclear physics: Extending the drip line (pp 1022-1024; N&V)
Two new neutron-rich isotopes presented in Nature this week shed new light on a fundamental question in nuclear physics; the limit of how many neutrons a given number of protons can bind. This is known as the neutron drip line. Thomas Baumann and colleagues report the experimental detection of the isotopes magnesium 40 (40Mg) and aluminium 42 (42Al), which suggests that the neutron drip line may be located towards heavier isotopes than currently believed.
Attempts to determine this limit for neutrons have been unsuccessful in all but the very lightest of elements. Here the team observe 40Mg and 42Al, giving a clearer indication of where the line may lie in this region of the periodic table — but conclude that producing rare drip line isotopes for nuclei with atomic numbers greater than 12 may be beyond the reach of current facilities.
Thomas Baumann (Michigan State University, East Lansing, MI, USA)
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Paul-Henri Heenen (Universite Libre de Bruxelles, Belgium
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 And finally… Lévy flights called into question (pp 1044-1048)
The behaviour of wandering albatrosses when searching for prey is not as previously thought, according to a report in this week’s issue of Nature.
Lévy flights are a type of random walk — a mathematical expression of a series of steps taken in random directions. They are characterized by many short steps and rare long steps, have no typical scale and can occur in physical and chemical systems. Previous attempts to demonstrate their existence in a natural biological system suggested that wandering albatrosses perform Lévy flights when searching for prey on the ocean surface — a finding followed by similar inferences about the search strategies of deer and bumblebees. Andrew M. Edwards and colleagues here present their evidence that this is not the case. Based on new high-resolution data and new analyses, the authors show that previous claims about the Lévy flight behaviour of wandering albatrosses were unfounded.
The authors also re-analyse existing data sets for deer and bumblebee, again finding that none exhibits evidence of Lévy flights. They suggest their results question the strength of empirical evidence for biological Lévy flights, and propose a novel method for testing the mathematical models of such behaviour.
Andrew M. Edwards (Fisheries and Oceans Canada, Nanaimo, BC, Canada)
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From Sunday 21 Oct the author will be travelling so email is the easiest way to organise an interview.
Note to reporters
On Friday 25 October, the Editor in Chief of Nature, Dr Philip Campbell, and the Chief Executive of Macmillan Publishers, Dr Annette Thomas, will accept the prestigious Principe de Asturias Award for Communications and Humanities. The award is given to “the person, group of people or institution whose work or research constitutes a significant contribution to universal culture in these fields”. It consists of a certificate, a sculpture especially designed for the Foundation by Joan Miró and 50,000 euros. http://www.fundacionprincipedeasturias.org/ing/
The award is to be given to two publications, Nature and Science. Commenting on the award, Philip Campbell said: ‘our mission ever since we were founded in 1869 has been to inspire scientists and citizens alike with the glories of science, as a truly independent voice. This prestigious award is an unprecedented accolade not only for us but for the inspiration provided by science for our culture.’
Please contact Ruth Francis, Senior Press Officer, Nature for further information.
ALSO IN THIS ISSUE…
 Kinetic redistribution of native and misfolded RNAs by a DEAD-box chaperone
(pp 1014-1018; N&V)
 Probable heat capacity signature of the supersolid transition (pp 1025-1028)
 Non-equilibrium degassing and a primordial source for helium in ocean-island volcanism
(pp 1037-1040; N&V)
 Group formation stabilizes predator–prey dynamics (pp 1041-1043; N&V)
 Regulation of cell cycle progression and gene expression by H2A deubiquitination
 Open-to-closed transition in apo maltose-binding protein observed by paramagnetic NMR
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 24 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 them on this release to avoid multiple mailings they will not appear in print on 25 October, but at a later date.***
 Hedgehog regulates smoothened activity by inducing a conformational switch
 Identification of Tim4 as a phosphatidylserine receptor
 BAI1 is an engulfment receptor for apoptotic cells upstream of the ELMO/Dock180/Rac module
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.
Utrecht: 7, 8
San Sebastian: 6
UNITED STATES OF AMERICA
La Jolla: 4
Santa Barbara: 4
East Lansing: 9
St Paul: 14
New York: 2, 10, 15
University Park: 12
For North America and Canada
Katie McGoldrick, Nature Washington
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For the UK/Europe/other countries not listed above
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