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This press release is copyright Nature.
VOL.464 NO.7285 DATED 04 MARCH 2010
This press release contains:
· Summaries of newsworthy papers:
Genetics: Human gut microbes sequenced
Relics: Triassic fossil sheds light on dinosaur evolution
Opinion: Stop laser uranium enrichment
Cancer: Mitochondrial DNA diversity
Biology: Novel process influences energy-generating process
Astronomy: A stellar link to our Galaxy's halo
Immunology: Mitochondria cause mayhem
Physics: A superconducting hydrocarbon
And finally… Optics: Keep it down in there!
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Genetics: Human gut microbes sequenced (pp 59-65)
Scientists have sequenced millions of human microbial gut genes in an effort to help understand and exploit the impact of gut microbes on human health. The study is unveiled in this week’s Nature.
The MetaHIT Consortium analysed the microbial DNA content of faecal samples collected from 124 Europeans. Around 3.3 million genes were sequenced, making the microbial gene set around 150 times bigger than the human gene complement. The genes were largely shared among individuals and most were bacterial — around 1,000 different bacterial species were present, with each person harbouring at least 160 such species. The team also define the minimal gut metagenome including bacterial and other DNA, as well as the minimal gut bacterial genome required for a bacterium to thrive in the gut.
CONTACT
Jun Wang (BGI-Shenzhen, China)
Tel: +86 755 2527 3789; E-mail: [email protected]
[2] Relics: Triassic fossil sheds light on dinosaur evolution (pp 95-98)
Analysis of the fossilized remains of a plant-eating reptile from the Middle Triassic of Tanzania suggests that Ornithodira — the taxonomic group including dinosaurs and pterosaurs — diversified early. The find is reported in this week’s Nature.
The remains represent one of the earliest known ornithodirans, dating to not long after the split between crocodiles and the last common ancestor of dinosaurs and pterosaurs. Sterling Nesbitt and colleagues describe it as a new species of silesaurid and a close relative to the dinosaurs.
The finding clarifies the relationships among the silesaurids, assigning previously described Triassic reptiles into a properly founded clade closely related to the ancestors of dinosaurs. Their results also suggest that silesaurids were not two-legged carnivores, as one might expect, but larger and more herbivorous.
CONTACT
Sterling Nesbitt (The University of Texas at Austin, TX, USA)
Tel: +1 480 215 6114; E-mail: [email protected]
Opinion: Stop laser uranium enrichment (pp 32-33)
The US Congress should take the lead on discouraging efforts to advance uranium-enrichment technology, argue Francis Slakey and Linda R. Cohen in an Opinion piece in this week’s Nature. They believe that the newest laser enrichment technology – called separation of isotopes by laser excitation (SILEX) – offers more potential risks than benefits. It is not critical for expansion of the nuclear power industry today, or in a future where greenhouse-gas emissions are tightly capped and the nuclear industry favoured. Capital costs and regulatory policies will determine the size of that industry. “Rather, the development and potential risk of misappropriation of an enrichment facility too small and efficient to be detected could be a game changer for further nuclear proliferation,” say the duo.
The US Nuclear Regulatory Commission (NRC) is considering an application to operate a full-scale commercial SILEX plant in North Carolina; this is open to public petition until 15 March. A final decision is expected to take at least another year. Slakey and Cohen urge Congress to require that proliferation risks be evaluated as part of the NRC licensing process, starting with the SILEX application. If the proliferation risks of such technologies beyond the licensee’s control are deemed too high, requested users should not be licensed, they say. Such a barrier would discourage commercial research and development in this area.
CONTACT
Francis Slakey (Georgetown University, Washington, DC, USA)
Tel: +1 202 687 7870; E-mail: [email protected]
[3] Cancer: Mitochondrial DNA diversity (AOP)
DOI: 10.1038/nature08800
*** This paper will be published electronically on Nature's website on 3 March 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 4 March, but at a later date. ***
Mitochondrial DNA is more heterogeneous than was thought, a study of normal and cancerous human cells shows. The paper, published in this week’s Nature, provides new insights into the nature and variability of mitochondrial DNA sequences, and has implications for cancer biomarker development and forensic analysis.
Human cells can house hundreds of mitochondria, each containing up to 10 copies of presumed identical mitochondrial DNA. Bert Vogelstein and colleagues show that these copies are often not identical, and can vary dramatically from tissue to tissue within individuals. The study shows that our tissues contain a mix of mitochondrial genotypes, cautioning the value of forensic tests that exclude identity on the basis of a mismatch between mitochondrial DNA isolated two different tissue types — for example sperm vs hair.
CONTACT
Bert Vogelstein (Howard Hughes Medical Institute, Baltimore, MD, USA)
Tel: +1 410 955 8878; E-mail: [email protected]
[4] Biology: Novel process influences energy-generating process (pp 121-125)
The protein SIRT3 regulates fatty acid oxidation by a novel mechanism — the reversible removal of acetyl groups from target enzymes. The results, revealed in this week’s Nature, may have therapeutic relevance for metabolic disorders such as diabetes and cardiovascular disease.
SIRT3, a protein deacetylase found in mitochondria, is induced in the liver and brown adipose tissue during fasting, where it mediates the deacetylation of several mitochondrial proteins, Eric Verdin and colleagues report. One such protein, called long-chain acyl CoA dehydrogenase (LCAD), is involved in fatty acid oxidation, the process by which the body metabolises fatty acids to release energy.
Without SIRT3, LCAD becomes hyperacetylated, which diminishes its activity and reduces fatty acid oxidation, the team shows. And mice lacking SIRT3 display all the hallmarks of fatty acid oxidation disorders during fasting, including reduced ATP levels and intolerance to cold. Dysregulated fatty acid oxidation has been linked with various metabolic diseases, so if these results could be replicated in humans, it is possible that SIRT3-boosting therapies could prove useful.
CONTACT
Eric Verdin (Gladstone Institute of Virology and Immunology, San Francisco, CA, USA)
Tel: +1 415 734 4808; E-mail: [email protected]
[5] Astronomy: A stellar link to our Galaxy's halo (pp 72-75)
A recently discovered star in the Sculptor dwarf galaxy is chemically very similar to the metal-poor stars of our Galaxy’s stellar halo, according to a paper in this week’s Nature. This similarity supports the idea that the halo was assembled from objects related to present-day dwarf galaxies.
Our Galaxy’s stellar halo contains stars that are very deficient in metals, compared to typical stars in the rest of the Galaxy. Current cosmological models indicate that the Galactic halo was formed by the accretion of many smaller systems, yet the failure to find such metal-poor stars in present-day dwarf galaxies seemed to exclude their progenitors as significant contributors to the halo.
Following the recent discovery of an extremely iron-poor star in the Sculptor dwarf galaxy, Anna Frebel and colleagues have measured the abundances of 11 elements in the star, using high-resolution spectroscopy. The abundance pattern follows that seen in metal-poor halo stars, indicating that the systems destroyed to form the Galactic halo billions of years ago were not fundamentally different from the progenitors of present-day dwarf galaxies.
CONTACT
Anna Frebel (Harvard University, Cambridge, MA, USA)
Tel: +1 512 461 7907; E-mail: [email protected]
[6] Immunology: Mitochondria cause mayhem (pp 104-107; N&V)
Mitochondrial debris from damaged cells can trigger inflammation, a Nature study suggests. The finding helps explain how apparent sepsis can sometimes be caused by severe trauma even when no infection is present.
Mitochondrial debris can be found in the circulation of seriously injured trauma patients who show no signs of bacterial infection, Carl J. Hauser and colleagues show. Such debris can activate white blood cells called neutrophils, triggering systemic inflammation and damaging organs.
Mitochondria, energy-generating cellular organelles, are thought to be derived from bacteria and their DNA shares similarities. These similarities may be enough, the authors speculate, for the immune system to trigger a sepsis-like state when it encounters mitochondrial debris.
CONTACT
Carl Hauser (Beth Israel Deaconess Medical Center, Boston, MA, USA)
Tel: +1 617 632 9931; E-mail: [email protected]
Michael Matthay (University of California, San Francisco, CA, USA) N&V Author
Tel: +1 415 353 1206; E-mail: [email protected]
[7] Physics: A superconducting hydrocarbon (pp 76-79; N&V)
Superconductivity at temperatures up to 18 kelvin has been discovered in crystals of a simple hydrocarbon molecule, intercalated with potassium or rubidium. The discovery, reported in this week’s Nature, opens up a new family of organic molecules to the search for high-temperature superconductors, and to the study of superconducting mechanisms.
The new superconductor is picene (C22H14), a molecule made of five benzene rings sharing edges with one another, which crystallizes into an ordered molecular solid. By introducing alkali metal atoms into the crystal lattice, Yoshihiro Kubozono and colleagues were able to induce metallic behaviour, and superconductivity, in this normally semiconducting material. In potassium-doped picene, the authors present evidence for two different superconducting phases with approximate composition K3picene, with superconducting transition temperatures (Tcs) of 7 kelvin and 18 kelvin.
The Tc of 18 kelvin is promisingly high, as compared with most other organic superconductors; of these, only alkali-metal-intercalated C60 (fullerene) compounds exhibit higher Tcs. As picene belongs to a large family of molecules based on fused benzene rings, other superconducting hydrocarbons may be awaiting discovery.
CONTACT
Yoshihiro Kubozono (Okayama University, Japan)
Tel: +81 86 251 7850; E-mail: [email protected]
Matthew Rosseinsky (University of Liverpool, UK) N&V Author
Tel: +44 151 794 3499; E-mail: [email protected]
[8] And finally… Optics: Keep it down in there! (pp 80-84)
By using nano-engineering techniques to integrate optical communications circuits with high-performance microprocessors, the intolerable amplification noise usually generated at the interface can be reduced by over 70 per cent. Presented in this week’s Nature, this new method for integrating optical and electrical fields in photodetectors could prove crucial in powerful computer systems and telecommunications.
Germanium photodetectors are often used in telecommunication and other optical devices because, unlike silicon photodetectors, they can detect light in the near-infrared region of the spectrum. Though germanium avalanche photodetectors — named for their charge amplification system — can achieve high input gain from low-power optical signals, they also generate intolerably high intrinsic noise.
Yurii A. Vlasov and colleagues generated strongly non-uniform electric fields in the germanium amplification layer of photodetectors. This reduced the region of impact ionization to just 30 nanometres, thus significantly lowering the amplification noise that is commonly generated.
CONTACT
Yurii Vlasov (IBM Watson Research Center, Yorktown Heights, NY, USA)
Tel: +1 914 9452 028; E-mail: [email protected]
ALSO IN THIS ISSUE…
[9] Quantum computers (pp 45-53)
[10] Helical crack-front instability in mixed-mode fracture (pp 85-89; N&V)
[11] Changes in Hox genes’ structure and function during the evolution of the squamate body plan (pp 99-103)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 3 March 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 4 March, but at a later date. ***
[12] Transcriptional Control of Preadipocyte Determination by Zfp423
DOI: 10.1038/nature08816
[13] IL-25 elicits a multi-potent progenitor cell population that promotes Th2 cytokine response
DOI: 10.1038/nature08901
[14] Nuocytes represent a new innate effector leukocyte that mediates type-2 immunity
DOI: 10.1038/nature08900
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
CANADA
Waterloo: 9
CHINA
Guangzhou: 1
Shenzhen: 1
DENMARK
Aarhus: 1
Copenhagen: 1
Kongens Lyngby: 1
FRANCE
Evry: 1
Illkirch: 11
Jouy en Josas: 1
Palaiseau: 1
GERMANY
Berlin: 2
Heidelberg: 1
Pfaffenwaldring: 9
IRELAND
Dublin: 14
ITALY
Milan: 1
JAPAN
Fukuoka: 7
Hachioji: 1
Ibaraki: 9
Ishikawa: 1
Kiryu: 1
Okayama: 7
Saitama: 9
NETHERLANDS
Ede: 1
NEW ZEALAND
Wellington: 11
SOUTH AFRICA
Cape Town: 2
SPAIN
Barcelona: 1, 10
Madrid: 1
SWITZERLAND
Geneva: 11
Lausanne: 11
UNITED KINGDOM
Bristol: 9
Cambridge: 1, 14
London: 6
UNITED STATES OF AMERICA
California
Malibu: 9
Palo Alto: 13
Pasadena: 5
San Francisco: 4
Stanford: 9
Illinois
Chicago: 2
Maryland
Baltimore: 3, 12
Beltsville: 13
College Park: 9
Massachusetts
Boston: 4, 6, 10, 12
Cambridge: 5
Danvers: 4
Missouri
Kansas City: 11
New York
New York: 2
Palisades: 2
Yorktown Heights: 8
North Carolina
Durham: 4
Ohio
Cleveland: 3
Pennsylvania
Philadelphia: 13
Pittsburgh: 4
Radnor: 14
Texas
Austin: 2
Utah
Salt Lake City: 2
Washington
Seattle: 2, 13
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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