Biomaterials: A silken trap for water

Summaries of newsworthy papers: An exoplanet's atmosphere probed from the ground, ‘Missing DNA’ link to obesity, Smells like a human, Protein marks malarial proteins for export, Signalling pathway crucial for cancer stem-cell survival, The quantum glow of photosynthesis, A more complex role for RAF inhibitors

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This press release is copyright Nature.

VOL.463 NO.7281 DATED 04 FEBRUARY 2010

This press release contains:

· Summaries of newsworthy papers:

Astronomy: An exoplanet's atmosphere probed from the ground

Genetics: ‘Missing DNA’ link to obesity

Neuroscience: Smells like a human

Biology: Protein marks malarial proteins for export

Oncology: Signalling pathway crucial for cancer stem-cell survival

Biophysics: The quantum glow of photosynthesis

Cell biology: A more complex role for RAF inhibitors

And finally…Biomaterials: A silken trap for water

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

· Geographical listing of authors

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[1] Astronomy: An exoplanet's atmosphere probed from the ground (pp 637-639; N&V)

A ground-based telescope has been used to detect probable fluorescent emission from methane in the atmosphere of a 'hot Jupiter'-type extrasolar planet. The result has implications for understanding the atmospheres of other strongly irradiated planets, and promises a wealth of future measurements of molecular abundances in exoplanet atmospheres.

In the past few years, infrared spectrometers mounted on space telescopes have been used to probe the compositions and physical conditions of exoplanet atmospheres — revealing the presence of water, methane, carbon dioxide and carbon monoxide in the atmospheres of two hot-Jupiter-type planets.

In this week's Nature, Mark Swain and colleagues report measurements of the emission spectrum of one of these planets, HD 189733b, obtained using a ground-based telescope in Hawaii. In a spectral region not accessible to the space-based instruments, the authors find an unexpected, bright emission feature that seems to arise from the fluorescence of atmospheric methane — which has also been observed in the atmospheres of Jupiter, Saturn and Titan. The presence of fluorescent emission requires a departure from local thermodynamic equilibrium — a possibility that may therefore need to be considered when interpreting measurements from other exoplanets that are strongly irradiated by their host stars.

The authors' results were made possible by a new calibration technique that should be readily applicable to many other telescopes, promising a bright future for ground-based exoplanet spectroscopy.

CONTACT
Mark Swain (Jet Propulsion Laboratory, Pasadena, CA, USA)
Tel: +1 818 455 2396; E-mail: [email protected]

Seth Redfield (Wesleyan University, Middletown, CT, USA) N&V author
Tel: +1 860 685 3669; E-mail: [email protected]

[2] Genetics: ‘Missing DNA’ link to obesity (pp 671-675)

A rare genetic deletion may cause a highly-penetrant form of obesity, a Nature paper suggests.

The 593 kilobase deletion on chromosome 16 was initially noted in a small group of obese individu. als, but a follow-up genome-wide association study (GWAS) of over 16,000 individuals suggests the mutation may account for around 0.7% of morbid obesity cases.

Numerous single base pair changes, or single nucleotide polymorphisms (SNPs) as they are known, have been linked with obesity, but these account only for a small fraction of the known heritable component. This cleverly designed study, performed by R. G. Walters and colleagues, highlights the value of small cohort studies and large-scale follow-up GWASs to identify missing heritability in obesity and other complex traits.

CONTACT
Robin Walters (Imperial College London, UK)
Tel: +44 20 7594 6531; E-mail: [email protected]

[3] Neuroscience: Smells like a human (AOP)
DOI: 10.1038/nature08834

***This paper will be published electronically on Nature's website on 03 February 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 04 February, but at a later date. ***

The repertoire of odorant receptor proteins that malaria-transmitting mosquitoes use to identify their human hosts has been characterized, as reported in a study published online this week in Nature. The analysis of the human-emitted odorants recognized by the mosquitoes may prove useful in tracking and controlling the transmission of malaria.

Malaria afflicts hundreds of millions of people each year, especially in sub-Saharan Africa. Similar to other insects that are disease carriers, the malaria-transmitting mosquito locates its human host primarily through olfaction. Although it is known that human odour is detected by olfactory sensory neurons, the molecular basis of the process has been unknown.

John Carlson and colleagues engineered mosquito olfactory receptor genes into transgenic fruitflies to study odours one by one. This allowed the scientists to identify those receptors responding to human odours. They also compared the complete odorant repertoires of mosquitoes and fruitflies in relation to the different ecological lifestyles of the two species. These studies will provide new potential molecular targets in the struggle against malaria.

CONTACT
John Carlson (Yale University, New Haven, CT, USA)
Tel: +1 203 432 3541; E-mail: [email protected]

[4] & [5] Biology: Protein marks malarial proteins for export (pp 627-631; 632-636)

A key enzyme that determines whether malaria parasite proteins are released into host cells is revealed in this week’s Nature. The protein is an attractive molecule for antimalarial drug development.

In order to survive and avoid detection by the host, the malaria parasite releases hundreds of proteins into host red blood cells. Two groups, led by Alan Cowman and Daniel Goldberg, have discovered that the protease plasmepsin V cleaves a common structural motif found on the malarial proteins, thus marking them for export. Development of a potent inhibitor of this protein may be a valid strategy to block the virulence and intracellular survival program of the malaria parasite.

CONTACT
Alan Cowman (The Walter & Eliza Hall Institute of Medical Research, Melbourne, Australia)
Tel: +61 3 9345 2446; E-mail: [email protected] Author paper [4]

Daniel Goldberg (Washington University School of Medicine, St Louis, MO, USA)
Tel: +1 314 362 1514; E-mail: [email protected] Author paper [5]

[6] Oncology: Signalling pathway crucial for cancer stem-cell survival (pp 676-680)

The discovery of a signalling pathway that promotes the survival of cancer-initiating cells in chronic myeloid leukaemia (CML) could aid the design of new treatment regimes. The find is reported in this week’s Nature.

Leukaemia-initiating cells (LICs) are the small, slowly dividing subset of cells that drive the recurrence of certain types of leukaemia. Atsushi Hirao and colleagues show that the TGF-–FOXO signalling pathway has an essential role in the maintenance of these cells, and that treatment with a TGF- inhibitor impairs the ability of cultured LICs to cause cancer growth.

CML occurs when specific regions of two particular chromosomes swap over, yielding a cancer-causing tyrosine kinase that is permanently ‘switched on’. But although the tyrosine-kinase-blocking drug imatinib kills leukaemia cells, it fails to target LICs, meaning that remission can sometimes be short-lived. Combining imatinib with a TGF- inhibitor could be a potential answer, the authors speculate, as the strategy appears promising in a mouse model of CML.

CONTACT
Atsushi Hirao (Kanazawa University Cancer Research Institute, Ishikawa, Japan)
Tel: +81 76 265 2726; E-mail: [email protected]

[7] Biophysics: The quantum glow of photosynthesis (pp 644-647; N&V)

The efficiency with which energy is transferred by photosynthetic proteins can be explained by quantum mechanics instead of classical laws, states a study published online this week in Nature. This conclusion comes from the observation that distant molecules within photosynthetic proteins are 'wired' together by quantum coherence for more efficient light-harvesting.

Though the vital role of photosynthesis in harvesting life on the Earth is well known, it has been a mystery how the proteins involved work so efficiently in capturing and transferring energy. Previous work on energy transfer of photosynthetic proteins found evidence of quantum-mechanical effects at play, though these studies were conducted at lower temperatures, of up to 180 K, where such effects should be less important.

Gregory Scholes and colleagues used spectroscopy to study a five-nanometre-wide photosynthetic protein from marine algae. They found direct evidence of quantum-coherent sharing of electronic excitation in the proteins under biologically relevant room-temperature conditions.

CONTACT
Gregory Scholes (University of Toronto, Ontario, Canada)
Tel: +1 416 946 7532; E-mail: [email protected]

Rienk van Grondelle (VU University, Amsterdam, Netherlands) N&V author
Tel: +31 20 598 7930; E-mail: [email protected]

[8] Cell biology: A more complex role for RAF inhibitors (AOP)
DOI: 10.1038/nature08833

***This paper will be published electronically on Nature's website on 03 February 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 04 February, but at a later date. ***

A class of kinase inhibitors with promise in cancer treatments may have a more complex role than previously believed, according to research published online in Nature this week. In mouse models, RAF inhibitors are shown to have opposing roles depending on the cellular context, which has implications for their clinical use.

Abnormal activation of the RAS–RAF signalling pathway occurs in many cancers, and is an attractive target for therapeutic development in oncology. Shiva Malek and colleagues demonstrate that in tumours with BRAF mutations, RAF inhibitors block the signalling pathway and decrease tumour growth as expected. However, the team go on to show that in another class of tumours where BRAF is not mutated, the same inhibitors can promote signalling and in some cases increase tumour growth. Furthermore, insights are provided into how these opposing roles occur mechanistically. Although these are early findings, they highlight the importance of selecting patients with BRAF mutations in clinical trials with these inhibitors.

CONTACT
Shiva Malek (Genentech Inc, South San Francisco, CA, USA)
Tel: +1 650 467 3784; E-mail: [email protected]

[9] And finally… A silken trap for water (pp 640-643)

The water-capturing ability of spider silk is due to the unique fibre structure that forms after wetting, a Nature study suggests. It’s thought the discovery, which has already led to the production of artificial fibres with similar abilities, might find industrial applications in processes requiring water collection or liquid aerosol filtering.

The dew-adorned appearance of spider webs on misty mornings beautifully illustrates how efficiently webs can collect water from air. Lei Jiang and colleagues show that this skill is due to the unique fibre structure that forms after wetting — periodic spindle-knots made of random nanofibrils are separated by joints made of aligned nanofibrils.

The structure gives rise to a surface energy gradient between the spindle-knots and joints, and a difference in the pressure acting on the water droplets. Together these features drive the continuous condensation and directional collection of water drops around spindle-knots. Inspired by their findings, the team also fabricate artificial fibres that successfully mimic the structural features and water-collecting ability of spider silk.

CONTACT
Lei Jiang (The Chinese Academy of Sciences, Beijing, China)
Tel: +86 10 8262 1396; E-mail: [email protected]

ALSO IN THIS ISSUE…

[10] Migrating tremors illuminate complex deformation beneath the seismogenic San Andreas fault (pp 648-652)
DOI: 10.1038/nature08755

[11] Multiple native states reveal persistent ruggedness of an RNA folding landscape (pp 681-684)
DOI: 10.1038/nature08717

[12] Experimental evidence for a frustrated energy landscape in a three-helix-bundle protein family (pp 685-688)
DOI: 10.1038/nature08743

[13] Structure of the amantadine binding site of influenza M2 proton channels in lipid bilayers (pp 689-692)
DOI: 10.1038/nature08722

ADVANCE ONLINE PUBLICATION

***This paper will be published electronically on Nature's website on 03 February 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 04 February, but at a later date. ***

[14] CHD7 cooperates with PBAF to control multipotent neural crest formation
DOI: 10.1038/nature08733

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
Melbourne: 4
Sydney: 7
Waurn Ponds: 4

BELGIUM
Edegem: 2

CANADA
Montreal: 2
Toronto: 7

CHINA
Beijing: 9

ESTONIA
Tartu: 2

FINLAND
Helsinki: 2
Oulu: 2

FRANCE
Amiens: 2
Arras: 2
Caen: 2
Lille: 2
Lyon: 2
Nancy: 2
Nantes: 2
Nimes : 2
Paris: 2
Rouen: 2
Saint Etienne: 2
Strasbourg: 2
Villejuif: 2

GERMANY
Heidelberg: 1
Stuttgart: 1

ITALY
Padova: 7
Perugia: 5

JAPAN
Aichi: 6
Ishikawa: 6
Tokyo: 6

NETHERLANDS
Utrecht: 2

SWEDEN
Gothenburg: 2

SWITZERLAND
Lausanne: 2
Zurich: 12

UNITED KINGDOM
Cambridge: 2, 12
Harrow: 2
Hinxton: 2
London: 1, 2
Oxford: 2

UNITED STATES OF AMERICA

Arizona
Tucson: 1

California
Berkeley: 11
Los Angeles: 1
Menlo Park: 10
Pasadena: 1
Stanford: 11, 14

Colorado
Boulder: 8

Connecticut
New Haven: 3

District of Columbia
Washington: 11

Georgia
Atlanta: 1

Illinois
Chicago: 14

Iowa
Ames: 13

Massachussetts
Cambridge: 2
Charlestown: 2

Missouri
St Louis: 5

Pennsylvania
Philadelphia: 2, 13

Tennessee
Nashville : 3

Texas
Dallas: 14

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
Rachel Twinn, Nature, London
Tel: +44 20 7843 4658; E-mail: [email protected]

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Published: 04 Feb 2010

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