Planets, Proteins and Palaeoclimate

Latest news ftom Nature 22 December 2011

This press release contains:

---Summaries of newsworthy papers:

Planetary science: A compact system of hardy planets

Neuroscience: Potential treatment for imprinting disorders

Outlook: How to test and regulate traditional Asian medicine

Virology: New host proteins that interact with HIV-1

Cancer: Immunotherapy comes of age

Palaeoclimate: A cold northern driver for southeast African wet phases

Electronics: Organic semiconductors gain through strain

Physics: Elusive 'Verwey' structure of magnetite uncovered

Organic chemistry: Making amide bonds

And finally... Beyond ultracold

---Mention of papers to be published at the same time with the same embargo

---Geographical listing of authors

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[1] Planetary science: A compact system of hardy planets (pp 496-499; N&V)

The discovery of a compact system of planets orbiting a former red-giant star is reported in this week’s Nature. These bodies must have survived engulfment in the red-giant envelope and may be the cores of giant planets whittled down by the evolving star.

When a main-sequence star evolves into a red giant, any planets orbiting in close proximity (less than the Earth–Sun distance) are expected to be swallowed up by the star. Whether planets can endure this engulfment and how this may affect star evolution has remained unclear. Observations of the former red giant KIC 05807616, a ‘hot B subdwarf’ star, reveal unusual signals. Stéphane Charpinet and colleagues propose that these oscillations indicate the presence of two nearly Earth-sized bodies orbiting KIC 05807616.

The authors suggest that these bodies could be the cores of giant planets that diminished in size when dragged into the red-giant envelope. Moreover, they infer that these bodies may have triggered the mass loss necessary for the formation of the hot B subdwarf.

CONTACT

Stéphane Charpinet (Université de Toulouse, France)
E-mail: [email protected]
Please note this author is travelling in the US and can also be contacted via the following telephone number until 20 December: +1 805 893 6358

Valerie Van Grootel (Université de Liège, Belgium) Co-author
Tel: +32 4366 9730; E-mail: [email protected]

Eliza Kempton (University of California, Santa Cruz, CA, USA) N&V author
Tel: +1 831 459 3809; E-mail: [email protected]

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[2] Neuroscience: Potential treatment for imprinting disorders (AOP; N&V)
DOI: 10.1038/nature10726

A method for reactivating dormant alleles of a gene disrupted in Angelman syndrome may offer a therapeutic strategy for this so-called imprinting disorder, a report in Nature this week suggests. Agents that can activate the silenced gene in mice are identified, including an FDA-approved cancer drug.

Angelman syndrome is a rare neurodevelopmental disorder caused by dysfunction of the maternal allele of the Ube3a gene. The paternal copy is typically intact, but silenced in neurons, thus restoring function to this copy may offer a potential therapeutic strategy against Angelman syndrome. Performing a drug screen on mouse neurons with the dormant allele, Benjamin Philpot and colleagues discover that a group of drugs called topoisomerase inhibitors are capable of activating paternal Ube3a. When delivered to live mice, these agents activate paternal Ube3a in multiple regions of the nervous system, and the effects persist for at least 12 weeks after ending treatment.

The authors suggest that topoisomerase inhibitors may have the potential to rescue various symptoms associated with loss of Ube3a function. Although some drugs from this family are approved for cancer therapy and are well tolerated, the authors caution that potential off-target effects of these drugs remain to be investigated.

CONTACT
Benjamin Philpot (University of North Carolina, Chapel Hill, NC, USA)
Tel: +1 919 966 0025; E-mail: [email protected]

Arthur Beaudet (Baylor College of Medicine, Houston, TX, USA) N&V author
Tel: +1 713 798 4795; E-mail: [email protected]

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Outlook: How to test and regulate traditional Asian medicine (pp S98-S100)

For regulatory agencies to approve the use of traditional herbal remedies, they need to be rigorously tested in clinical trials. However, existing randomized controlled trial designs do not take the unique aspects of traditional medicines into account, argue Liang Liu, Elaine Lai-Han Leung and Xiaoying Tian.

In a Perspective in Nature Outlook: Traditional Asian Medicine, the authors draw a parallel between the way that traditional Asian medicine is practised and the trend in modern medicine towards personalized treatments. New clinical trial designs that are appropriate for personalized medicine might well be suitable for traditional Asian medicines too. “Redesigning clinical trials will accelerate the blending of these two styles of healing, for the benefit of humankind,” they claim.

Other regulatory issues restrict the use of traditional Asian medicines worldwide. Reporter Natasha Gilbert investigates whether Western rules can govern Eastern traditions. In Europe, many Asian medicines used to be sold as dietary supplements and subject to lighter regulation — yet they can be potent drugs. A new European directive aims to close this loophole, putting the onus on makers of herbal remedies to perform complex biological analyses to characterize their products — a requirement beyond the capabilities and resources of many manufacturers — and could result in popular herbal remedies being banned.

CONTACT
Liang Liu (Macau University of Science and Technology, China)

E-mail: [email protected]

For background information on Natasha Gilbert's article, please contact the press office.

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[3], [4] & [5] Virology: New host proteins that interact with HIV-1 (AOP)

DOI: 10.1038/nature10719

DOI: 10.1038/nature10693

DOI: 10.1038/nature10718

*** These papers will be published electronically on Nature's website on 21 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 22 December, but at a later date. ***

New interactions between HIV-1 and human proteins are revealed in three papers published in Nature this week.

In a comprehensive screen, Nevan Krogan and colleagues have determined several human protein interaction partners of all 18 proteins from HIV-1, discovering many new human proteins and complexes targeted by HIV-1, including 11 proteins that act to inhibit HIV-1 replication.

In a second paper they follow up on one of these interactions, between the HIV protein Vif and its newly identified interaction partner CBF-b. Proteins known as restriction factors protect cells from infection by blocking virus replication, but most retroviruses have developed counter-defence mechanisms. One such counter-defence mechanism is mediated by the HIV-1 protein Vif, which targets the restriction factor APOBEC3G for degradation. Krogan and colleagues show that the transcription factor CBF-b associates with Vif and is needed for Vif to counteract APOBEC3G.

Xiaofang Yu and colleagues also make this finding in a separate study. Both groups agree that antiviral therapies targeting the CBF-b–Vif interaction represent a promising intervention against HIV-1 infection.

CONTACT
Nevan Krogan (University of California, San Francisco, CA, USA) Author papers [3] & [4]
Tel: +1 415 476 2980; E-mail: [email protected]

Xiaofang Yu (Johns Hopkins University, Baltimore, MD, USA) Author paper [5]
Tel: +1 410 955 3768; E-mail: [email protected]

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[6] Cancer: Immunotherapy comes of age (pp 480-489)

Cancer therapies that work by activating the patient’s immune system can yield long-lasting, positive results, and may even succeed where conventional cancer therapies have failed, a Review published in this week’s Nature suggests.

Cancer immunotherapeutics, which include antibody therapies and vaccination, have long been a goal of some immunologists. But after decades of disappointment, it seems that therapy is finally coming of age with various successful proof-of-concept clinical trials.

Ira Mellman and colleagues provide an overview of recent results including the anti-CTLA4 antibody ipilimumab, which significantly boosts the survival of patients with metastatic melanoma. The review attempts to unravel the reasons why so many immunotherapeutics have failed, describes the biology underpinning current immunotherapeutic design, and highlights the various hurdles that remain.

CONTACT
Ira Mellman (Genentech, South San Francisco, CA, USA)
Tel: +1 650 467 9514; E-mail: [email protected]

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[7] Palaeoclimate: A cold northern driver for southeast African wet phases (pp 509-512)

Cold events in the remote Northern Hemisphere, rather than the surface temperature of the nearby Indian Ocean, appear to have been the main driver of wet periods in tropical southeast Africa over the past 17,000 years. This conclusion, reported in this week’s Nature, comes from a continuous environmental record preserved in a marine sediment core offshore of one of Africa’s largest rivers.

Considerable debate surrounds the relative importance of atmospheric and oceanic influences on the hydrology and climate of southeast Africa since the peak of the last glaciation, about 20,000 years ago. Rainfall in this region is sensitive to latitudinal shifts in the location of the atmospheric region known as the intertropical convergence zone (ITCZ), which can occur in response to northern high-latitude climate changes. Another important forcing mechanism is thought to be the surface temperature of the southwest Indian Ocean, with warmer temperatures promoting wetter conditions.

Enno Schefuß and colleagues disentangle these two influences with the help of a sediment core from the Indian Ocean floor, near the outflow of the Zambezi River. This river’s large catchment area and its location at the current southern limit of seasonal ITCZ migration makes its discharge a sensitive indicator of the region’s terrestrial climate. The sediments of the 6.5-metre-long core provide a record of this climate, and of sea surface temperature, stretching back 17,000 years. The authors show that phases of high rainfall and river discharge correlate well with cold events in the Northern Hemisphere, known from Greenland ice cores, and cannot be explained by changes in local sea surface temperature.

CONTACT
Enno Schefuß (University of Bremen, Germany)
Tel: +49 421 2186 5526; E-mail: [email protected]

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[8] Electronics: Organic semiconductors gain through strain (pp 504-508)

A new method for improving the performance of organic semiconductors is reported online in Nature this week. Borrowing an idea from conventional silicon electronics, Zhenan Bao and colleagues show that introducing strain into the crystal lattice of an organic semiconductor film during processing can significantly increase the mobility of the charge carriers, setting the stage for faster devices.

Thin films of organic semiconductors, deposited from solution, show great promise for the development of cheap and flexible electronic devices, but generally suffer from much lower charge-carrier mobility than their inorganic counterparts. Strained films of inorganic semiconductors, such as silicon or germanium, have long been known to exhibit increased mobility, but until now this avenue has not been explored in solution-processed organic materials.

Bao and colleagues prepare strained thin films of the organic semiconductor TIPS-pentacene, by shearing the solution containing the material during film deposition. The authors show that the resulting strain changes the molecular packing of the molecules, increasing the overlap of electronic orbitals, and increasing the carrier mobility. The highest mobility achieved was more than twice the highest value previously reported in this material — boding well for future applications.

CONTACT
Zhenan Bao (Stanford University, CA, USA)

Tel: +1 650 723 2419; E-mail: [email protected]

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[9] Physics: Elusive 'Verwey' structure of magnetite uncovered (AOP)
DOI: 10.1038/nature10704

The complex structure of the charge-ordered transition state in magnetite — first observed in 1939 — has finally been determined. This solution confirms aspects of some early models and identifies dynamics that contribute to the properties of the distorted structure, according to a report in Nature this week.

The first example of a charge-ordering transition in a solid at low temperatures was described in magnetite (Fe3O4) and was named the Verwey transition after the author who made the discovery. This general class of behaviour, which changes electronic conducting properties, has since been observed in other transition metal oxides; however, the precise structure of the Verwey state in magnetite has remained elusive. J. Paul Attfield and colleagues use X-ray analysis to study single crystals of magnetite and determine the complex structural distortions that characterize the enigmatic Verwey state. Understanding such ordering in this experimental structure may provide a basis for further investigation of the properties of the Verwey state in magnetite and related phenomena in other transition metal oxides, the researchers conclude.

CONTACT
J. Paul Attfield (University of Edinburgh, UK)
Tel: +44 131 651 7229; E-mail: [email protected]

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[10] Organic chemistry: Making amide bonds (pp 471-479)

A Review article in this week's issue of Nature describes recently discovered amide-bond-forming reactions and explores how organic chemists are using these new methods to synthesize small molecules, peptides, polymers and proteins. It concludes Nature’s year-long compilation of news features, primary research and Review articles to commemorate the UNESCO/IUPAC International Year of Chemistry.

Amide bonds form the backbone of peptides and proteins, and these chemical motifs are also found in many pharmaceutical agents and some polymers. Despite their prevalence, many existing methods used to synthesize amide bonds have severe limitations, including the use of expensive reagents and the generation of significant quantities of waste products.

In their Review article, Vijaya Pattabiraman and Jeffrey Bode discuss the advantages and limitations of well-known amide-bond-forming reactions and assess the potential of newly discovered methods to make these compounds. The hope is that some of these new methodologies will facilitate the synthesis of previously unattainable small-molecule pharmaceuticals, therapeutic peptides, and non-natural proteins in a cost-effective and environmentally sustainable manner.

CONTACT
Jeffrey Bode (ETH Zürich, Switzerland)
Tel: +41 44 633 2103; E-mail: [email protected]

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[11] And finally... Beyond ultracold (pp 500-503; N&V)

A method for cooling quantum gases to even colder temperatures, by reducing their entropy, is presented in this week’s Nature. The technique relies on a new form of ‘blockade’ effect between neutral atoms, which may also enable the implementation of controlled quantum gates in a scalable computing architecture.

Ultracold quantum gases, comprising neutral atoms confined in an ‘optical lattice’, hold great potential for simulating the physics of solid materials. Although quantum gases are now routinely cooled to nanokelvin temperatures, still further cooling will be necessary to simulate strongly correlated electron systems, such as quantum magnets and high-temperature superconductors. At such low temperatures, with the atoms already in their lowest-energy state, further cooling requires a way of removing entropy from the system.

Markus Greiner and colleagues report a new phenomenon, called ‘orbital excitation blockade’, that makes such cooling possible. The authors show that, when two atoms occupy the same lattice site, the excitation of one of them to a higher energy level (orbital) suppresses the excitation of the other. Excited atoms can then be removed from the system, taking entropy with them.

This ability to control the number of atoms occupying each lattice site is also of interest for quantum computing, as it should allow the creation of quantum registers with thousands of lattice-trapped atoms, and, in principle, the implementation of two-quantum-bit gates for generalized computing.

CONTACT
Markus Greiner (Harvard University, Cambridge, MA, USA)
Tel: +1 617 595 3811; E-mail: [email protected]

Gretchen Campbell (National Institute of Standards and Technology and University of Maryland, Gaithersburg, MD, USA) N&V author
Tel: +1 301 975 4271; [email protected]

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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
Brussels: 1
Leuven: 1
Liège: 1

CANADA
Montréal: 1

CHINA
Jilin: 5

FRANCE
Toulouse: 1

GERMANY
Bremen: 7
Bremerhaven: 7
Garching: 1

IRELAND
Dublin: 4

ITALY
Pino Torinese: 1

POLAND
Krakow: 1

SOUTH KOREA
Kyunggi-Do: 8

SPAIN
Santa Cruz de La Palma: 1

SWITZERLAND
Zürich: 10

UNITED KINGDOM
Edinburgh: 9

UNITED STATES OF AMERICA
Arizona
Tucson: 1
California
Berkeley: 4
La Jolla: 4
Menlo Park: 8
San Francisco: 3, 4
South San Francisco: 6
Stanford: 8
Iowa
Ames: 1
Idaho
Rexburg: 8
Maryland
Baltimore: 5
Massachusetts
Boston: 6
Cambridge: 8, 11
Minnesota
Minneapolis: 3
North Carolina
Chapel Hill: 2
Pennsylvania
Philadelphia: 4, 6
Texas
Dallas: 4
Utah
Salt Lake City: 4

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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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Published: 22 Dec 2011

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