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This press release is copyright Nature.
VOL.450 NO.7173 DATED 20 DECEMBER 2007
This press release contains:
· Summaries of newsworthy papers:
Neuroscience: Brain cells are smarter than you think
Fossil record: Terrestrial ancestors of whales
Medicine: Looking for cancer in all the right places
Optics: A fine-tooth comb
Stem cells: A case of mistaken functional identity
Superconductors: Who needs phonons?
Palaeoclimate: Early warming signs
Planetary science: Dating the Moon's formation
And finally... Making the most of melodious mistakes
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] [2] & [3] Neuroscience: Brain cells are smarter than you think (pp 1195-1200 & AOP)
DOI:10.1038/nature06447
DOI:10.1038/nature06445
***Papers [2] & [3] will be published electronically on Nature's website on 19 December 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 December, but at a later date.***
Individual brain cells can make a bigger contribution to behaviour and are capable of more computations than previously thought, suggest three papers published in this week’s Nature. The mammalian brain faces a serious resource problem - there aren’t enough neurons to have one responsible for every single perception, behaviour or memory. To increase its storage capacity the brain is thought to use overlapping patterns of activity across many interconnected neurons instead, but new research indicates that this underestimates the part individual cells can play.
Using a new method for stimulating neurons in the part of the mouse brain involved in whisker-touch with light, a team led by Karel Svoboda demonstrate that brief bursts of activity in a few neurons are all it takes to trigger learning and decision-making. In another study, Michael Brecht and Arthur R. Houweling managed to pin down the influence of a single cell on a rat’s ability to sense touch. By electrically stimulating neurons in the barrel cortex they found that slightly increasing a neuron’s activity directly affected whether or not rats reported a touch-like sensation. In a third technically impressive study, Karel Svoboda and Christopher D. Harvey zoomed in on the individual connections - or ‘synapses’ - between neurons. Each neuron has many synapses, scattered across its branch-like dendrites. As an animal learns, synapses become stronger or weaker, changing the pattern of connections thought to store information. Previous experiments showed that stimulating a single synapse can change its strength, but computer models predict ‘crosstalk’ between neighbouring synapses. Harvey and Svoboda confirmed this prediction, showing that the neighbours of recently strengthened connections were themselves easier to potentiate. This hints at a kind of neuronal filing system, in which connections relevant to similar kinds of behaviour might cluster together.
These papers add to our growing understanding of the complex processing that can go on within a single cell, and raise interesting questions about how widespread these effects are.
CONTACT
Karel Svoboda (Howard Hughes Medical Institute, Ashburn, VA, USA) Author papers [1] & [3]
Tel: +1 571 209 4113; E-mail: [email protected]
Michael Brecht (Humboldt University, Berlin, Germany) Author paper [2]
Tel: +49 30 2093 6772; E-mail: [email protected]
Bernado Sabatini (Harvard Medical School, Boston, MA, USA) N&V Author
Tel: +1 617 432 5670; E-mail: [email protected]
[4] Fossil record: Terrestrial ancestors of whales (pp 1190-1194)
The marine mammals known as cetaceans - whales, dolphins and porpoises - originated about 50 million years ago in south Asia, but their terrestrial ancestor is something of a mystery. A paper in this week’s Nature suggests that it is likely to have been a racoon-sized animal from India known as a raoellid, which probably took to the water in times of danger.
J Thewissen and his colleagues present evidence for a close relationship between whales and raoellids, which lived at about the same time as the earliest whales. The structures of the skull and ear region of raoellids are very similar to those of early whales, and their bone thickness and isotope evidence both indicate that these creatures spent much of their time in water. Raoellids, however, were mainly herbivorous on land, so the spur for the ancestors of whales to take to the water was probably an abundance of aquatic prey.
According to independent molecular evidence, hippos are the closest relatives of today’s whales. However, hippos don’t appear in the fossil record until some 35 million years after whales diverged from their terrestrial ancestors. Thewissen and colleagues’ raoellid Indohyus now provides the missing Eocene piece of the jigsaw.
CONTACT
J Thewissen (Northeastern Ohio Universities College of Medicine, Rootstown, OH, USA)
Tel: +1 330 325 6295; E-mail: [email protected]
Commentary: Brain-enhancing drugs: in sickness and in health?
Two scientists writing a Commentary in this week's issue of Nature want to stimulate readers' brains - in more ways than one. Barbara Sahakian and Sharon Morein-Zamir discuss the increasing use of cognitive-enhancing drugs by healthy individuals.
Doctors already prescribe these drugs to treat cognitive disabilities and improve quality of life for patients with neuropsychiatric disorders and brain injury. Now, prescription use is being extended to other situations, including for shift-workers and for jetlag. Meanwhile, non-prescription use by the general public is becoming increasingly commonplace.
A questionnaire that Sahakian and Morein-Zamir sent to scientific colleagues on both sides of the Atlantic revealed fairly casual use by some academics, and the authors believe that such usage raises ethical questions that cannot be ignored. While the appeal of brain-boosting drugs - to help one study longer, work more effectively or better manage everyday stresses - is understandable, potential users must consider the pros and cons of their choices.
To trigger broader discussion of the ethical issues of using enhancing drugs, Sahakian and Morein-Zamir challenge readers with several questions, to which they hope readers will respond in an online forum on the social-networking site, Nature Network. http://network.nature.com/forums/naturenewsandopinion/
Their questions include: Would you boost your own brain power? How would you react if you knew your colleagues - or your students - were taking cognitive enhancers? How should society react? The authors will be available to answer questions raised by visitors to the online forum for two weeks following publication.
CONTACT
Sharon Morein-Zamir (Addenbrooke's Hospital, Cambridge, UK)
Tel: +44 1223 767 035; E-mail: [email protected]
[5] Medicine: Looking for cancer in all the right places (pp 1235-1239)
Viable tumour-derived epithelial cells (also known as circulating tumour cells or CTCs) have been identified in the blood of cancer patients, and the hope is that these CTCs will enable physicians to characterize and monitor certain kinds of cancer in a non-invasive manner. A paper published in this week’s Nature describes the development of a unique microfluidic platform (the ‘CTC-chip’) that can efficiently and selectively separate CTCs from peripheral blood samples.
Mehmet Toner and colleagues have used the device to identify CTCs successfully in the peripheral blood of patients with metastatic lung, prostate, pancreas, breast and colon cancer, and they have shown that they can use the CTC-chip to monitor an individual’s response to anti-cancer therapy. The approach seems to isolate more viable CTCs - and is simpler - than other methods that have been used to isolate these rare cells, so the hope is that this device could be used in clinical settings to diagnose cancer patients rapidly and monitor them while they are undergoing treatment.
CONTACT
Mehmet Toner (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 724 5336; E-mail: [email protected]
Jonathan W. Uhr (University of Texas Southwestern Medical Center, Dallas, TX, USA) N&V Author
Tel: +1 214 648 1226; E-mail: [email protected]
[6] Optics: A fine-tooth comb (pp 1214-1217)
Optical frequency 'combs' - light sources that emit a spectrum of separate, equally spaced frequencies - are revolutionizing spectroscopy and measurement techniques. A paper in this week’s Nature has come up with a new, much simpler way to generate these combs, which until now have been cumbersome to produce.
Tobias Kippenberg and colleagues use a tiny disc-like structure on a silicon chip and illuminate it with a conventional laser diode. The laser light and the resonator then interact to produce an optical frequency comb that emits in the infrared. Previously, a bulky, mode-locked femtosecond laser had to be commandeered and carefully stabilized before a comb could be generated.
The simplicity of the scheme - combined with the prospect of a reduction in size, cost and power used - should open up a wide variety of applications for optical frequency combs.
CONTACT
Tobias Kippenberg (Max Planck Institut fuer Quantenoptik, Garching, Germany)
Tel: +49 89 32905 727; E-mail: [email protected]
Steven T Cundiff (University of Colorado, Boulder, CO, USA) N&V Author
Tel: +1 303 492 7858; E-mail: [email protected]
[7] Stem cells: A case of mistaken functional identity (pp 1230-1234)
Stem cells are pluripotent - in other words, they have the potential to develop into all kinds of other cells. Until now, a key contributor to this incipient state was thought to be a protein known as Nanog, which disappears once the cells start to differentiate. It turns out that Nanog has a rather different role to play, as revealed in a paper published in this week's Nature.
Ian Chambers and colleagues show that Nanog safeguards the pluripotent state of embryonic stem cells, resetting them if they start to differentiate when they shouldn't - it is not an essential cog in the machinery responsible for pluripotency, as previously believed. It also has another, hitherto unsuspected, part to play in helping egg and sperm cells to develop correctly.
Nanog seems to appear in waves during early development and implantation of the embryo. Before too long we may have a clearer picture of how this molecule brings its talents together.
CONTACT
Ian Chambers (University of Edinburgh, Scotland, UK)
Tel: +44 131 651 7242; E-mail: [email protected]
[8] Superconductors: Who needs phonons? (pp 1177-1183)
‘Classic’ superconductivity was explained in the 1950s, with vibrations of the crystal lattice (phonons) identified as playing the key role. But theorists started to investigate whether the involvement of phonons was strictly necessary - could one have a superconductor in which phonons didn't play a role? A review article in Nature this week presents a restatement of a model that is emerging as a powerful framework for interpreting superconductivity without phonons.
In the 1950s Nobel-winning BCS (Bardeen, Cooper, Schrieffer) theory, a superfluid of electron pairs interacts via the exchange of phonons. The subsequent discovery of a series of unconventional superconductors demonstrates that the lattice vibrations or phonons are not vital. Gilbert Lonzarich and colleagues argue that attraction between electron pairs without phonons can be more sensitive to the precise crystal structure and electronic and magnetic properties of a material.
CONTACT
Gilbert Lonzarich (University of Cambridge, UK)
Tel: + 44 1223 337 391; E-mail: [email protected]
[9] Palaeoclimate: Early warming signs (pp 1218-1221)
A period of intense global warming happened 55 million years ago and - like the current warming - it was associated with the release of greenhouse gases into the oceans and the atmosphere. But which came first? A paper in this week’s Nature shows that, around North America’s east coast at least, warming probably began before the main injection of greenhouse gases took place.
Appy Sluijs and co-workers analysed two sections of sediment from the New Jersey shelf that provide exceptionally high-resolution records of environmental change at the boundary between the Palaeocene and Eocene epochs of the Tertiary period. They found that the environment started to change and the ocean surface began to warm several thousand years before the type of greenhouse gas that can be detected in the geological record built up.
One explanation for this sequence of events is that when eventually the deep ocean grew warmer as well, submarine gas hydrates decomposed and released massive amounts of the greenhouse gas methane. But the cause of the early warming itself is unclear and could be due to the release of greenhouse gases that can’t be ‘seen’ in the geological record.
CONTACT
Appy Sluijs (Utrecht University, Netherlands)
Tel: +31 30 253 2638; E-mail: [email protected]
[10] Planetary science: Dating the Moon's formation (pp 1206-1209)
The Moon probably formed from molten debris ejected from the ‘proto’-Earth as a result of a mighty impact from a body the size of Mars. A paper in this week’s Nature analyses the processes that could have happened in the Moon immediately afterwards, as well as giving a better idea of just when the the Moon might have formed.
M Touboul and colleagues measured the tungsten isotopes in lunar metals to determine the age of the magma ocean created immediately after the impact as a result of the high energies involved. The analysis of lunar metals, rather than rocks, allowed the authors to avoid contamination from a different source - that produced by cosmic rays at the lunar surface.
The team found that the Moon’s magma ocean solidified between about 50 and 150 million years after the Solar System formed. They also discovered that the ratio of two tungsten isotopes was the same for the lunar and terrestrial mantles, indicating either that the Moon is derived mainly from Earth’s material or that they equilibrated in the aftermath of the giant impact.
CONTACT
M Touboul (Swiss Federal Institute of Technology, Zurich, Switzerland)
Tel: +41 1 632 6441; E-mail: [email protected]
Alan Brandon (Johnson Space Center, Houston, TX, USA) N&V Author
Tel: +1 281 224 6408; E-mail: [email protected]
[11] And finally... Making the most of melodious mistakes (pp 1240-1244)
Why is it that even the best athletes and musicians do not always perform highly practiced movements as well as they could? One suggestion is that this is all part of a natural variation. But a paper in this week’s Nature indicates that subtle variability is a means of achieving a trial-and-error improvement in performance.
Evren Tumer and Michael Brainard investigated changes in the song of adult bengalese finches (Lonchura striata). Birdsong is a complex learned skill requiring precise and rapid vocal control. The team showed that the birds were continuously monitoring the consequences of minute variations in their song and were using the information to optimize their output.
The researchers suggest that these tiny variations reflect experimentation by the nervous system to optimize performance.
CONTACT
Evren Tumer (University of California, San Francisco, CA, USA)
Tel: +1 415 502 3279; E-mail: [email protected]
ALSO IN THIS ISSUE
[12] After a dozen years of progress the origin of angiosperms is still a great mystery (pp 1184-1189)
[13] Structural basis for gate-DNA recognition and bending by type IIA topoisomerases (pp 1201-1205)
[14] Internal motions of a quasiparticle governing its ultrafast nonlinear response (pp 1210-1213)
[15] Trench-parallel flow and seismic anisotropy in the Mariana and Andean subduction systems
(pp 1222-1225)
[16] Allometric degree distributions facilitate food-web stability (pp 1226-1229)
[17] High-fidelity transmission of sensory information by single cerebellar mossy fibre boutons
(pp 1245-1248)
[18] Stochastic gene expression out-of-steady-state in the cyanobacterial circadian clock (pp 1249-1252)
[19] Toll-like receptor signalling in macrophages links the autophagy pathway to phagocytosis (pp 1253-1257)
[20] Cdc48/p97 promotes reformation of the nucleus by extracting the kinase Aurora B from chromatin (pp 1258-1262)
[21] Visualizing spatially correlated dynamics that directs RNA conformational transitions (pp 1263-1267; N&V)
[22] Segrosome structure revealed by a complex of ParR with centromere DNA (pp 1268-1271)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 19 December 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 December, but at a later date.***
[23] Host genome surveillance for retrotransposons by transposon-derived proteins
DOI: 10.1038/nature06499
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 seethe PDF of the paper for full details.
AUSTRALIA
Sydney: 22
GERMANY
Berlin: 14
Cologne: 10
Darmstadt: 16
Garching: 6
INDIA
Uttarakhand: 4
JAPAN
Tokyo: 19
NETHERLANDS
Texel: 9
Utrecht: 9
NEW ZEALAND
Lower Hutt: 9
SWITZERLAND
Geneva: 20
Zurich: 10, 20
UNITED KINGDOM
Cambridge: 7, 8
Edinburgh: 7, 8
London: 17
Richmond: 12
UNITED STATES OF AMERICA
California
Berkeley: 13, 16
Davis: 8
San Francisco: 11
Santa Cruz: 9
Florida
Jupiter: 19
Maryland
Bethesda: 5
Massachusetts
Boston: 5
Cambridge: 18
Michigan
Ann Arbor: 5, 15, 21
New Mexico
Los Alamos: 8
New York
Cold Spring Harbor: 1
Ohio
Kent: 4
Rootstown: 4
Tennessee
Memphis: 19
Texas
College Station: 9
Houston: 9, 22
Virginia
Ashburn: 1
Wyoming
Laramie: 4
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
Rachel Twinn, Nature London
Tel: +44 20 7843 4658; E-mail [email protected]
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