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This press release is copyright Nature.
VOL.452 NO.7187 DATED 03 APRIL 2008
This press release contains:
· Summaries of newsworthy papers:
Astrophysics: Combing the skies for earths
Commentary: IPCC underestimates challenge of global warming
Molecular pharmacology: Moving in on drug resistance
Climate change: Another core bites the dust
Cancer biology: Route to thwarting skin cancer stem cells?
Materials: Superinsulators and superconductors
Tectonics: In pole position
And finally… Insight into short-term information storage
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Astrophysics: Combing the skies for earths (pp 610-612; N&V)
An ‘astro-comb’ to help scientists scour the skies for Earth-like planets is reported in Nature this week. The device improves on current technology, allowing greater precision in astronomical radial velocity measurements — and actual astronomical measurements should become a reality in May 2008.
The current count of extrasolar planets stands at 277, none of them Earth-like. Most were detected by a method that ‘sees’ planets down to about five times the mass of the Earth. Chih-Hao Li and colleagues describe a stable wavelength reference comb for astronomical spectrographs that will enable them to enhance the sensitivity of such measurements by a substantial degree, in principle allowing them to detect the tiny accelerations induced by Earth-sized planets orbiting in the habitable zones of other stars.
In a related News and Views article, RW Walker says that although the concept has been around for some time, its realization in practice ‘could be a major breakthrough in precision for astronomical spectroscopy.’
CONTACT
Chih-Hao Li (Harvard University, Cambridge, MA, USA)
Tel: +1 516 784 8986; E-mail: [email protected]
Ronald Walsworth (Harvard-Smithsonian, Cambridge, MA, USA)
Tel: +1 617 495 7274; E-mail: [email protected]
Gordon Walker (University of British Columbia, Victoria, Canada) N&V author
Tel: +1 250 592 6205; E-mail: [email protected]
Commentary: IPCC underestimates challenge of global warming (pp 531-532)
Stabilizing atmospheric carbon-dioxide concentrations to help mitigate the effects of global warming is one of the greatest challenges our world faces. In a commentary in this week’s Nature, Roger Pielke Jr, Tom Wigley and Christopher Green argue that the Intergovernmental Panel on Climate Change (IPCC) has underestimated the need for new efforts directed at reducing emissions.
They contend that the emissions scenarios that the IPCC has developed for looking at future climate change assume that “business as usual” will include continuous significant increases in energy efficiency, and that the emissions of carbon for a given amount of energy generation will continually decrease.
These spontaneous changes should instead be included in any assessment of the technology required to achieve climate stabilization, the authors point out. Thus, they conclude, the scenarios can lead users to drastically underestimate the amount of “decarbonization” required in the economy. “The IPCC plays a risky game in assuming that spontaneous advances in technological innovation will carry most of the burden of achieving future emissions reductions,” the authors write.
CONTACT
Roger Pielke (University of Colorado, Boulder, CO, USA)
E-mail: [email protected]
Tom Wigley (National Center for Atmospheric Research, Boulder, CO, USA)
Tel: +1 303 497 2690; E-mail: [email protected]
Christopher Green (McGill University, Montréal, Québec, Canada)
E-mail: [email protected]
[2] Molecular pharmacology: Moving in on drug resistance (pp 604-609; N&V)
People with weakened immune systems — such as transplant recipients or cancer patients undergoing chemotherapy — are often plagued by fungal infections. Antifungal drugs do not always work because some organisms can pump them out of their cells before they do any damage. A paper in this week’s Nature reveals a mechanism of how such drugs have the unwanted effect of boosting the fungus’ arsenal of pumps used to fight them off.
Anders Näär and colleagues have identified a crucial protein — known as Pdr1p — in pathogenic fungi such as yeast (Saccharomyces cerevisiae) and the organism responsible for thrush-like infections (Candida glabrata) that directly binds the drug once it has gained entry into the cell. This binding stimulates the fungus to step up production of its defensive pumping gear, and the drug is ejected.
Pdr1p can bind different types of antifungal drug, giving rise to multidrug resistance. The authors hope that understanding the mechanism behind this resistance will help in the design of drugs to thwart it.
CONTACT
Anders Näär (Harvard Medical School, Charlestown, MA, USA)
Tel: +1 617 724 7942; E-mail: [email protected]
André Goffeau (Université de Louvain, Louvain-la-Neuve, Belgium) N&V author
Tel: +32 10 47 36 14; E-mail: [email protected]
[3] Climate change: Another core bites the dust (pp 616-619)
A high-resolution dust record from an ice core in East Antarctica sheds new light on the interplay between dust flux and climate. The ice core, which provides an undisturbed climate sequence for the past 800,000 years, shows that dust flux is strongly correlated with Antarctic temperature during glacial periods.
Dust particles in the atmosphere can affect temperature by absorbing or reflecting incoming solar radiation. Moreover, previous studies have suggested that production, transport and deposition of dust can be influenced by climatic changes on glacial–interglacial timescales.
In Nature this week, Fabrice Lambert and colleagues present a high-resolution record of dust from the EPICA (European Project for Ice Coring in Antarctica) Dome C ice core in East Antarctica. They then match this record to climate indicators such as stable isotopes from ice cores and marine sediments. The record confirms increased atmospheric dust loading during cold episodes in the Quaternary period. The data suggest that dust is linked to temperature as the climate becomes colder, pointing to a gradual influence of the glacial Antarctic climate on lower-latitude climate.
The authors propose that the observed increase in glacial dust flux over the last eight glacial periods can be attributed to a strengthening of South American dust sources, together with a longer atmospheric dust particle lifetime in the upper troposphere resulting from a reduced hydrological cycle during the ice ages.
CONTACT
Fabrice Lambert (University of Bern, Switzerland)
Tel: + 41 31 631 4465; E-mail: [email protected]
[4] Cancer biology: Route to thwarting skin cancer stem cells? (pp 650-653)
Skin cancers in which the upper layers of the skin grow uncontrollably — known as epithelial tumours — are maintained by special cancer stem cells. A paper in this week’s Nature has identified how the cells in these tumours signal to one another in order to keep the population of rogue stem cells topped up.
Joerg Huelsken and colleagues studied this type of skin cancer in mice. They found that transplanting material derived from the cancer stem cells to a cancer-free mouse caused identical cancer development in the recipient. And they pinpoint a protein known as beta-catenin as being crucial for sustaining these cancer stem cells — in genetically engineered animals without the protein, the tumours shrink because there is no longer a signal to tell the cells to keep renewing themselves.
The team’s discovery may open up a possible route to treating this type of skin cancer in humans. They show that squamous cell carcinomas — the human equivalent of the mouse tumours — also rely on beta-catenin. As the stem cells responsible for renewing normal skin do not depend on beta-catenin, targeting this molecule could help wipe out the cancer stem cells in a malignant tumour.
CONTACT
Joerg Huelsken (Ecole Polytechnique Federale de Lausanne, Switzerland)
Tel: +41 21 652 5885; E-mail: [email protected]
[5] Materials: Superinsulators and superconductors (pp 613-615; N&V)
Disorder in thin superconducting films enforces their electronic texture of droplet-like superconducting islands — and fine-tuning this disorder will drive the system from behaving as a superconductor to becoming an insulator. A paper in this week’s Nature homes in on events at the transition and identifies a new ‘superinsulating’ state that has infinite resistance.
Valerii Vinokur and colleagues knew that a distinct conductivity state — known as a Cooper-pair insulator — forms in the vicinity of the transition. They studied this in films of titanium nitride and discovered a condition where a Cooper-pair insulator becomes a superinsulator. The superinsulating state is destroyed by a strong critical magnetic field, and breaks down at a critical voltage that is analogous to the critical current in superconductors.
CONTACT
Valerii Vinokur (Argonne National Laboratory, Argonne, IL, USA)
Tel: +1 773 627 9615; E-mail: [email protected]
Rosario Fazio (Scuola Normale Superiore, Pisa, Italy) N&V author
Tel: +39 50 509 059; E-mail: [email protected]
[6] Tectonics: In pole position (pp620-623)
Scientists present a new palaeomagnetic reconstruction of the motion of the Earth’s tectonic plates over the past 320 million years, to reveal the global average of continental motion and rotation through time, finding evidence for true polar wander.
The observed motion of continents relative to the Earth’s spin axis is a combination of two factors: rotation of the entire Earth relative to its spin axis, ‘true polar wander’, and the motion of individual tectonic plates. Hotspots — thought to arise from relatively fixed thermal plumes of material that rise up from the deep mantle — are useful reference points and are commonly used to track the paths of plates. However, geological records of suitable hotspot chains, such as Hawaii, only exist back to about 130 million years ago.
In Nature this week, Bernhard Steinberger and Trond Torsvik overcome this problem by computing the global average of continental motion and rotation in a palaeomagnetic reference frame over the past 320 million years. They identify two components: a steady northward motion and, during certain time intervals, clockwise and anticlockwise rotations, which they interpret as true polar wander. The authors propose that this could be used as a new reference frame, appropriate for relating surface to deep-mantle processes from 320 million years ago until hotspot tracks become useful.
CONTACT
Bernhard B Steinberger (Geological Survey of Norway, Trondheim, Norway)
Tel: +47 7390 4371; E-mail: [email protected]
[7] And finally… Insight into short-term information storage (AOP)
DOI: 10.1038/nature06860
***This paper will be published electronically on Nature's website on 2 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 3 April, but at a later date. ***
The human brain can create short-term memories that last only a few seconds — for example, for performing tasks such as adding two numbers or comparing the attractiveness of two faces. A paper in this week’s Nature investigates how the brain allocates its limited capacity for visual working memory, and in doing so begins to resolve a long-standing uncertainty.
This uncertainty hinges on whether we store high-quality representations of a small number of objects (as in a small number of high-resolution digital photographs) or low-quality representations of a large number of objects (as in a large number of low-resolution digital photographs). Weiwei Zhang and Steven Luck have tested these alternatives by using a short-term colour-recall task in which capacity and resolution were measured independently. They found that the observers stored a high-resolution representation of a subset of the objects and retained no information about the others.
The team concludes that short-term information storage does not discard quality in favour of quantity.
CONTACT
Weiwei Zhang (University of California, Davis, CA, USA)
Tel: +1 530 297 4420; E-mail: [email protected]
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 2 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 3 April, but at a later date. ***
[8] A deadenylation negative feedback mechanism governs meiotic metaphase arrest
DOI: 10.1038/nature06809
[9] Imaging of Rab5 activity identifies essential regulators for phagosome maturation
DOI: 10.1038/nature06857
[10] Genetic variation in human NPY expression affects stress response and emotion
10.1038/nature06858
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.
BELGIUM
Leuven: 5
DENMARK
Copenhagen: 3
FRANCE
Illkirch: 4
Saint-Martin-d’Heres: 3
GERMANY
Bochum: 5
Bremerhaven: 3
Regensberg: 5
ITALY
Milan: 3
NORWAY
Oslo: 6
Trondheim: 6
RUSSIA
Novosibirsk: 5
SOUTH AFRICA
Johannesburg: 6
SPAIN
Madrid: 4
SWITZERLAND
Bern: 3
Epalinges: 4
Lausanne: 4
UNITED KINGDOM
Cambridge: 3
UNITED STATES OF AMERICA
California
Davis: 7
Illinois
Argonne: 5
Iowa
Iowa City: 2, 7
Maryland
Baltimore: 2
Massachusetts
Boston: 2
Cambridge: 1
Charlestown: 2
New Jersey
Newton: 1
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
Jen Middleton, Nature London
Tel: +44 20 7843 4502; E-mail [email protected]
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