This press release is copyright Nature.
VOL.470 NO.7335 DATED 24 FEBRUARY 2011
This press release contains:
Summaries of newsworthy papers:
Climate science: Not a drop to drink
Neuroscience: Enzyme link to PTSD
News Features and Comment: The animal-testing conflict
Immunology: New vaccine boosts immune response
Biology: Stem cell model may yield ageing clues
Neuroscience: Helpless neurons
Biology: How prions propagate
Earth science: Volcanic tremor explained
Physics: Coupled quantum pendulums
Cell cycle: Nutrition and the developing brain
And finally… A leg-up for arthropod evolution
Mention of papers to be published at the same time with the same embargo
Geographical listing of authors
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[1] Climate science: Not a drop to drink (pp 518-521; N&V)
‘Megadroughts’ that lasted for millennia were a regular feature of Pleistocene interglacial periods in the southwestern United States (US), reports a paper in Nature this week. The study suggests that in the absence of anthropogenic climate change, this region would probably now be entering a cooler, wetter phase.
The southwestern US is known to have experienced decades-long droughts over the past two millennia but it has been unclear whether there were longer megadroughts, lasting for hundreds or thousands of years, and if so, how regular and intense they were. Peter Fawcett and colleagues analysed a lake sediment core from Valles Caldera, New Mexico. Using molecular palaeotemperature proxies to reconstruct the mean average temperatures and other indicators of shifts in ecosystem structure, they show that extended periods of drought occurred in the region during two long interglacials in the mid-Pleistocene — when mean average temperatures were similar to or above present-day values.
The authors suggest that these megadroughts, which had profound effects on water availability and ecosystem composition, were caused by the poleward expansion of the subtropical dry zone in response to warming. This climatic mechanism is similar to that predicted for the southwestern US as a result of anthropogenic warming and these Pleistocene arid periods may therefore be suggestive of future climate change in the region.
CONTACT
Peter Fawcett (University of New Mexico, Albuquerque, NM, USA)
Tel: +1 505 277 3867; E-mail: [email protected]
John Williams (University of Wisconsin, Madison, WI, USA) N&V author
Tel: +1 608 265 5537; E-mail: [email protected]
[2] Neuroscience: Enzyme link to PTSD (pp 492-497; N&V)
A new Nature paper linking female post-traumatic stress disorder (PTSD) to abnormal levels of a specific enzyme is helping unravel the sex-specific differences in fear physiology, and may aid the development of a biomarker for PTSD.
Levels of the enzyme pituitary adenylate cyclase-activating polypeptide (PACAP) are associated with PTSD diagnosis and symptoms in women (but not men) from a highly traumatized background, Kerry Ressler and colleagues demonstrate. And a mutation in the PACAP receptor predicts PTSD.
PACAP helps regulate the stress response in several species, but its role in humans is unclear. The current results, which are backed up by data showing that PACAP and its receptor are regulated by fear and oestrogen in rats and mice, hint that faulty PACAP signalling may contribute to the abnormal stress response that underlies PTSD in women.
CONTACT
Kerry Ressler (Emory University, Atlanta, GA, USA)
Tel: +1 404 727 7739; E-mail: [email protected]
Murray Stein (University of California, San Diego, CA, USA) N&V author
Tel: +1 858 534 6400; E-mail: [email protected]
News Features and Comment: The animal-testing conflict (pp 452-459)
Nearly a quarter of researchers, or people they know, have been affected negatively by protestors or activists, suggests an informal online poll conducted by Nature. The results of the poll of nearly 1,000 biologists are published in this week’s Nature as part of a special package on animal research.
Animal researchers who participated in the survey cited incidents including protests outside laboratories, vandalism, the ‘liberation’ of research animals and physical attacks. The findings also indicate that although more than 90% of respondents think that the use of animals in research is important, nearly one-third of researchers conducting animal research say they have ethical concerns about their work.
The content also includes a first-time, exclusive interview with Joseph Harris — a cancer researcher by day and a radical anti-animal-testing activist by night. Harris was arrested in 2006 while vandalizing a company with ties to animal testing and was the first person to be convicted under a UK law designed to protect companies terrorized by activists.
Finally, a Comment article examines whether scientists should ignore the possibility of attacks by activists and go on television to discuss the value of animal testing. Tipu Aziz and John Stein argue that in this electronic age, remaining silent isn’t an option. “Anyone can use Google to look up what a researcher does,” they say. “The sensible thing is to be proactive and prepared to defend our work.” Ranga Yogeshwar, on the other hand, advises scientists involved in the ethically complex field of animal research to “stay as far away from the camera as possible”. “On television,” he says, “emotionally-charged pictures rule. Scientists are charged with cruelty and the accusation cannot be countered with arguments: the screech of a monkey or whine of a dog drowns out every possible justification.”
Contact for background information on the News Features:
Brendan Maher (Features Editor, Nature, New York, NY, USA)
E-mail: [email protected]
Contacts for Comment articles:
John Stein (John Radcliffe Hospital, Oxford, UK)
E-mail: [email protected]
Tipu Aziz (John Radcliffe Hospital, Oxford, UK)
E-mail: [email protected]
Ranga Yogeshwar (Science journalist, Cologne, Germany)
E-mail: [email protected]
[3] Immunology: New vaccine boosts immune response (pp 543-547)
A new nanoparticle-based vaccine can boost the magnitude and persistence of vaccine-elicited antibody responses, a Nature paper reveals. The novel vaccine design offers a potential means of improving vaccine-mediated protection against the influenza virus.
The vaccine, developed by Bali Pulendran and colleagues, is made up of nanoparticles that contain the antigen and two different Toll-like receptor (TLR) ligands. Immunization protected completely against lethal avian and swine influenza virus strains in mice, and induced robust immunity against pandemic H1N1 influenza in rhesus macaques.
This new vaccine outperformed control vaccines that contained only one of the two TLR ligands, and intriguingly, the two TLR ligands and antigens needed to be delivered on two separate particles. From a practical point of view, this offers flexibility — a generic adjuvant-containing particle could be coupled with another particle containing the antigen of choice. Furthermore, as the various vaccine components are already licensed for human use, it is thought that this vaccine formulation might offer a universal platform for vaccine design against pandemics and emerging infections.
CONTACT
Bali Pulendran (Emory Vaccine Center, Atlanta, GA, USA)
Tel: +1 404 727 8945; E-mail: [email protected]
[4] Neuroscience: Helpless neurons (pp 535-539)
Increased presynaptic action onto certain neurons in the brain contributes to the learned helplessness behaviour in rats, reports work published in Nature this week. This behaviour, in which animals give up trying to escape from an inevitable foot shock, has been proposed as a model for major depression, suggesting that changes in these synapses may contribute to depression.
The cellular basis of depressive disorders is poorly understood; however, it has recently been shown that neurons in the lateral habenula (LHb) — a nucleus that projects to midbrain reward areas — can signal aversive outcomes and may be disrupted in depressive disorders. Roberto Malinow and colleagues examined the synaptic circuitry in the LHb of rats displaying learned helplessness — a model of depression whereby animals show reduced mobility and escape from an escapable situation. They found that there was enhanced signal transmission from excitatory synapses onto LHb neurons.
The team also show that depleting transmitter release in LHb with stimulation patterns similar to those used for deep brain stimulation reduces synaptic change and can also significantly reduce learned helplessness in rats.
CONTACT
Roberto Malinow (University of California, San Diego, CA, USA)
Tel: +1 858 246 0274; E-mail: [email protected]
[5] Biology: Stem cell model may yield ageing clues (AOP)
DOI: 10.1038/nature09879
***This paper will be published electronically on Nature's website on 23 February at 1800 London time / 1300 US Eastern Time (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 24 February, but at a later date. ***
A stem cell model of the premature ageing disorder Hutchinson–Gilford progeria syndrome is reported in Nature this week. The findings could aid the study of the mechanisms that regulate premature and normal ageing.
Hutchinson–Gilford progeria syndrome (HGPS) is a rare genetic disorder characterized by a rapid acceleration of the phenotypes associated with normal ageing, such as atherosclerosis and the degeneration of vascular smooth muscle cells (SMCs). Juan Carlos Izpisua Belmonte and colleagues generated induced pluripotent stem cells (iPSCs) from fibroblasts taken from patients with HGPS. Upon reprogramming, the HGPS-iPSCs lack the nuclear and epigenetic changes normally associated with premature ageing, the authors report. Directed differentiation of HGPS-iPSCs to SMCs led to the appearance of characteristics associated with premature ageing.
CONTACT
Juan Carlos Izpisua Belmonte (The Salk Institute for Biological Studies, La Jolla, CA, USA)
Tel: +1 858 453 4100, ext. 1130; E-mail: [email protected]
[6] Biology: How prions propagate (pp 540-542; N&V)
A new model of prion disease may represent a paradigm shift in the mechanisms thought to underlie these infectious, neurodegenerative disorders.
Prion diseases, such as Creutzfeldt–Jacob disease, have a clinically silent incubation period that can go on for years or decades, followed by an aggressive, short clinical phase. The new model, based on mouse studies, indicates that the spread of prions in the brain occurs in two distinct phases. In the first, longer, clinically silent phase, non-neurotoxic prions multiply exponentially until a defined limit is reached. Then the second, shorter plateau phase sees the amassed prions catalyse the formation of toxic prion particles. And whereas the length of the infectious phase is not dependent on prion concentration, the time it takes for the mouse to succumb after the plateau of infectivity is reached is inversely correlated with the amount of prion protein that it produces.
The model, proposed by John Collinge and colleagues in this week's Nature, hints that prion infectivity and toxicity are separate processes and, remarkably, that infectious and toxic particles may not be the same.
CONTACT
John Collinge (University College London, UK)
Tel: +44 20 7837 4888; E-mail: [email protected]
Reed Wickner (National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA) N&V author
Tel: +1 301 496 3452; E-mail: [email protected]
[7] Earth science: Volcanic tremor explained (pp 522-525; N&V)
The long-period seismicity known as volcanic tremor finds an appealingly simple explanation in this week’s Nature. A model of a rising plug of viscous magma, ‘wagging’ back and forth in its conduit, can reproduce the salient characteristics of tremor observed at explosive volcanoes around the world.
Volcanic tremor is a ubiquitous feature of explosive eruptions, which is of value for eruption forecasting. Yet, despite the consistent characteristics of tremor at different volcanoes, most models of tremor origin rely on specific properties of the volcanic conduit, and on the gas content of the erupting magma — properties that vary widely among volcanoes.
In formulating their new model, Mark Jellinek and David Bercovici start from a physical description that appears to be common to all explosive volcanic systems: a stiff, columnar plug of magma, surrounded by a gas-rich annulus of sheared bubbles near the conduit wall. The authors note that this structure will lend itself to an oscillation, or ‘wagging’, of the magma plug inside the annulus, which acts like a springy foam, resisting the motion of the plug. The model is able to explain the narrow band of tremor frequencies observed at volcanoes of widely varying structure and geometry, and also predicts the changes in the tremor frequency spectrum observed as an eruption proceeds.
CONTACT
Mark Jellinek (University of British Columbia, Vancouver, Canada)
Tel: +1 604 822 5079; E-mail: [email protected]
Stephen McNutt (University of Alaska, Fairbanks, AK, USA) N&V author
Tel: +1 907 474 7131; E-mail: [email protected]
[8] & [9] Physics: Coupled quantum pendulums (AOP)
DOI: 10.1038/nature09721
DOI: 10.1038/nature09800
***This paper will be published electronically on Nature's website on 23 February at 1800 London time / 1300 US Eastern Time 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 24 February, but at a later date. ***
The quantum analogue of two pendulums coupled by a spring is demonstrated for the first time in Nature this week. The results, published online by two independent groups, provide a new building block for quantum computing and simulation, and opportunities for coupling different types of object in hybrid quantum systems.
The simple harmonic oscillator — such as a pendulum, or a mass suspended on a spring — is a fundamental and ubiquitous physical system. Harmonic oscillators in the quantum realm include the mechanical vibrations of nanoscale cantilevers, or the vibrational motions of trapped atoms or ions. In previous experiments, information has been transported between quantized mechanical oscillators, but direct, controllable coupling — analogous to the spring connecting two macrosopic pendulums — has not previously been demonstrated.
In the two new experiments, single ions trapped in separate electrical potential wells play the part of the pendulums, and the electrical force between them (the ‘Coulomb interaction’) acts as the spring. Kenton Brown and colleagues trap single beryllium ions in wells separated by 40 micrometres; Rainer Blatt and colleagues trap calcium ions at a separation of 54 micrometres, and use additional ions in each trap as ‘antennae’ to amplify the coupling interaction. Both groups observe the expected flow of mechanical energy back and forth between the two wells, at the quantum level. The authors envisage a range of applications, including the ability to read out the state of one ion species with another, and a method for transferring information between different types of quantum bit.
CONTACT
Kenton Brown (National Institute of Standards and Technology, Boulder, CO, USA) Author paper [8]
Tel: +1 303 497 4364; E-mail: [email protected]
Rainer Blatt (University of Innsbruck, Austria) Author paper [9]
Tel: +43 512 507 6350; E-mail: [email protected]
[10] Cell cycle: Nutrition and the developing brain (AOP)
DOI: 10.1038/nature09867
***This paper will be published electronically on Nature's website on 23 February at 1800 London time / 1300 US Eastern Time 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 24 February, but at a later date. ***
Dietary nutrients are crucial for stimulating non-dividing neural stem cells into re-entering the cell cycle, according to research published online this week in Nature. This work, in the developing fruitfly, demonstrates how nutrients activate a signal from a tissue called fat body that trigger the reactivation of neuroblasts — or neural progenitors — and the research gives clues to how these cells avoid under or over proliferation in the body.
Little is known about how nutritional cues are detected by non-dividing neural stem cells and how this signal is relayed to reactivate their cell cycle to exit this state. Alex Gould and colleagues identify the relay mechanism regulating this nutritional checkpoint. They show that specific insulin-like peptides produced within the brain as a result of signals derived from the fat body induce the cell division once again — and the exit from this non-dividing state. The authors hope their approach will work in other animals, particularly mammals.
CONTACT
Alex Gould (MRC National Institute for Medical Research, London, UK)
Tel: +44 20 8816 2103; E-mail: [email protected]
[11] And finally… A leg-up for arthropod evolution (pp 526-530)
The discovery of an unusual creature — nicknamed the ‘walking cactus’ — in China may add to understanding of arthropod evolution. The finding, described in this week’s Nature, adds to the debate over whether the development of the characteristic hardened external skeleton began with the acquisition of robust legs.
Most groups of animals alive today first appeared in the fossil record during the Cambrian explosion, a period of rapid evolution some 500 million years ago. Jianni Liu and colleagues report the discovery of a previously unknown species of lobopodian from the Cambrian of southwest China. The creature, which is about six centimetres long, resembles a thin, soft-bodied worm and has ten pairs of robust, spiny and, probably, jointed appendages.
The authors suggest that the organism may be the closest known fossil relative of modern arthropods (animals with jointed legs, like spiders and crustaceans). Although the walking cactus may not be the common ancestor of these creatures, it has the most robust and arthropod-like limbs of any lobopodian so far. This could indicate that this branch of lobopodians evolved hardened legs before their bodies hardened, but it remains unclear whether this also applies to arthropods in general.
CONTACT
Jianni Liu (Free University of Berlin, Germany)
Tel: +49 30 83870187; E-mail: [email protected]
ALSO IN THIS ISSUE…
[12] Climate change and evolutionary adaptation (pp 479-485)
[13] An open-system quantum simulator with trapped ions (pp 486-491)
[14] Co-directional replication–transcription conflicts lead to replication restart (pp 554-557)
[15] Crystal structure of the CusBA heavy-metal efflux complex of Escherichia coli (pp 558-562)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 23 February at 1800 London time / 1300 US Eastern Time 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 24 February, but at a later date. ***
[16] Structural basis of RNA polymerase II backtracking, arrest and reactivation
DOI: 10.1038/nature09785
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.
AUSTRALIA
Bentley: 1
Crawley: 1
Melbourne: 12
AUSTRIA
Innsbruck: 9, 13
CANADA
Vancouver: 7
CHINA
Beijing: 11
Xi’an: 11
GERMANY
Berlin: 11
Martinsried: 9
Munich: 16
NETHERLANDS
Den Burg: 1
SPAIN
Barcelona: 5
UNITED KINGDOM
London: 6, 10
Nottingham: 14
UNITED STATES OF AMERICA
Arizona
Flagstaff: 1
California
La Jolla: 4, 5
Colorado
Boulder: 8
Connecticut
New Haven: 7
Florida
Miami: 2
Georgia
Athens: 3
Atlanta: 2, 3
Illinois
Argonne: 15
Iowa
Ames: 15
Maryland
Chevy Chase: 2
Massachusetts
Cambridge: 14
Minnesota
Duluth: 1
New Mexico
Albuquerque: 1
Los Alamos: 1
New York
New York: 3
Upton: 4
North Carolina
Durham: 3
Rhode Island
Providence: 1
Vermont
Burlington: 2
PRESS CONTACTS…
From North America and Canada
Neda Afsarmanesh, Nature New York
Tel: +1 212 726 9231; E-mail: [email protected]
From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
From the UK
Rebecca Walton, Nature, London
Tel: +44 20 7843 4502; E-mail: [email protected]
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