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This press release is copyright Nature.
VOL.472 NO.7341 DATED 07 APRIL 2011
This press release contains:
· Summaries of newsworthy papers:
Developmental biology: Stem cells generate eye-like structure
Biology: Gut flora and heart disease
Ecology: Biodiversity improves water quality *BRIEFING*
Materials science: High-frequency graphene transistors on diamond-like carbon
Cancer: Understanding lung cancer progression
And finally… How to switch off ‘the X factor’
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Developmental biology: Stem cells generate eye-like structure (pp 51-56; N&V)
Cultured stem cells can spontaneously organize themselves into a complex structure that resembles the developing embryonic eye, a Nature paper demonstrates. It is hoped the study will aid the development of stem cell-derived transplants for retinal repair.
Yoshiki Sasai and colleagues grew floating clusters of mouse embryonic stem cells in a carefully-designed tissue culture medium. The cells organized themselves into a three-dimensional, layered structure reminiscent of the optic cup, a two-walled pouch-like structure, which develops into the inner and outer layers of the retina during embryogenesis.
The self-directed organization of stem cells seen here was unexpected, because the culture started as patternless aggregates of homogeneous cells that were not pushed, pulled or ‘pressurized’ into any particular shape. Instead the study shows how formation of the optic cup depends on an intrinsic, sequential, self-organizing program that directs cell fate and position, and the overall shape of the optic cup.
CONTACT
Yoshiki Sasai (RIKEN Center for Developmental Biology, Kobe, Japan)
Tel: +81 78 306 1841; E-mail: yoshikisasai(at)cdb.riken.jp
Robin Ali (University College London, UK) N&V author
Tel: +44 207 608 6817; E-mail: r.ali(at)ucl.ac.uk
[2] Biology: Gut flora and heart disease (pp 57-63; N&V)
The ability of our gut flora to metabolize the dietary phospholipid phosphatidylcholine may influence how susceptible we are to cardiovascular disease (CVD), indicates a Nature paper published this week.
Plasma levels of three phosphatidylcholine metabolites — choline, betaine and trimethylamine N-oxide (TMAO) — are associated with an increased risk of CVD in humans, Stanley Hazen and colleagues demonstrate. Supplementing the diet of atherosclerosis-prone mice with choline accelerates atherosclerosis, but the effect is blocked if the animals’ gut flora is suppressed with antibiotics.
Consuming a lipid-rich diet is a known risk factor for CVD, but the influence of phospholipids — a subtype of lipid — is less clear. This study indicates that strategies designed to alter the gut’s microbial makeup may help prevent and treat atherosclerotic heart disease and its complications.
CONTACT
Stanley Hazen (Cleveland Clinic Foundation, OH, USA)
Tel: +1 216 445 9763; E-mail: hazens(at)ccf.org
Daniel Rader (University of Pennsylvania, Philadelphia, PA, USA) N&V author
Tel: +1 215 573 4176; E-mail: rader(at)mail.med.upenn.edu
[3] Ecology: Biodiversity improves water quality (pp 86-89; N&V) *BRIEFING*
Habitats with high levels of species biodiversity can harness a greater proportion of biologically active nutrients, such as nitrogen, than less diverse ecosystems, and a paper published in this week’s Nature explains how. The findings suggest that conserving species richness may help to buffer natural ecosystems against the ecological impacts of nutrient pollution.
Controlling excess nitrogen in water and maximizing its removal is an important goal for environmental policy. More diverse stream communities are known to extract nutrients more efficiently, but the mechanisms are poorly understood. Bradley Cardinale manipulated algal species diversity in models of stream ecosystems and found that nitrogen uptake increased linearly with species richness. Habitats with more species are able to take greater advantage of the niche opportunities in the environment, Cardinale suggests, in this case allowing them to take up more nitrates. This relationship disappeared when the niche structure was experimentally removed.
CONTACT
Bradley Cardinale (University of Michigan, Ann Arbor, MI, USA)
Tel: +1 805 893 4157; E-mail: bradcard(at)umich.edu
Andy Hector (University of Zurich, Switzerland) N&V author
Tel: +41 1 635 4804; E-mail: andrew.hector(at)uzh.ch
**The NSF are holding a webcast UNDER STRICT EMBARGO on Tuesday 05 April at 1900 London time / 1400 US ET; author Bradley Cardinale will discuss how biodiversity promotes water quality. To participate in the teleconference, please call +1 800 369 2182 or join the webcast at http://live.science360.gov. To obtain passwords providing access to the teleconference and/or webcast, e-mail Lily Whiteman ([email protected]). During the event, you can e-mail questions for Bradley Cardinale to: [email protected].**
[4] Materials science: High-frequency graphene transistors on diamond-like carbon (pp 74-78; N&V)
Diamond-like carbon is identified as a potential new substrate for graphene transistors in a paper in this week’s Nature. The devices exhibit stable high-frequency performance down to very low temperatures, providing a much larger operation window than conventional devices.
Transistors made from graphene — a flat sheet of carbon just one atom thick — have potential applications in radio-frequency microelectronic devices. The devices can be made by transferring high-quality graphene sheets, produced by chemical vapour deposition, to a suitable insulating substrate, such as silicon dioxide. However, the substrate can degrade the electronic properties and uniformity of the devices.
Phaedon Avouris and colleagues have identified diamond-like carbon, which is already used in the semiconductor industry, as a new substrate for graphene devices as they find it is less likely than silicon dioxide to lead to the deterioration of the device’s electronic properties. The authors demonstrate graphene transistors operating at radio frequencies with a cut-off as high as 155 gigahertz and with scalable gate length. Unlike conventional semiconductor devices, the high-frequency performance of the graphene devices exhibits little temperature dependence down to 4.3 kelvin.
CONTACT
Phaedon Avouris (IBM Thomas J. Watson Research Center, Yorktown Heights, NY, USA)
Tel: +1 914 945 2722; E-mail: avouris(at)us.ibm.com
Frank Schwierz (Ilmenau University of Technology, Germany) N&V author
E-mail: frank.schwierz(at)e-technik.tu-ilmenau.de
[5] Cancer: Understanding lung cancer progression (AOP)
DOI: 10.1038/nature09881
***This paper will be published electronically on Nature's website on 06 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 07 April, but at a later date. ***
A molecular mechanism involved in the progression of lung cancer is described in a paper in Nature this week. The newly identified mechanism has allowed scientists to determine the gene expression alterations that distinguish metastatic from non-metastatic tumours.
In a mouse model of lung cancer, Tyler Jacks and colleagues demonstrate that the gene encoding Nkx2-1 is downregulated during tumour progression. Nkx2-1 is a transcription factor that is a crucial regulator of lung development and can also suppress progression and metastasis in lung cancer, the researchers show. Downregulation of this transcription factor is associated with poorer outcome in patients with lung cancer. Nkx2-1 loss promotes metastasis at least in part by removing the Nkx2-1-mediated repression of a protein called Hmga2, which has a role in altering gene expression and tumour differentiation.
These findings reveal that Nkx2-1, previously identified as a lung cancer oncogene, can also function as a suppressor of lung cancer progression. This dual function seems to have a role in the mechanisms involved in tumour progression and metastasis.
CONTACT
Tyler Jacks (Massachusetts Institute of Technology, Cambridge, MA, USA)
Tel: +1 617 253 0262; E-mail: tjacks(at)mit.edu
[6] And finally… How to switch off ‘the X factor’ (AOP)
DOI: 10.1038/nature09872
***This paper will be published electronically on Nature's website on 06 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 07 April, but at a later date. ***
X-chromosome inactivation (XCI) — the process by which one of two copies of the X chromosome present in female mammals is ‘switched off’ — differs radically between placental mammal species, a Nature paper reveals.
During development, female placental mammals inactivate one copy of the X chromosome to avoid receiving a double dose of X chromosome gene products. Most XCI studies have focussed on mouse embryos, but Edith Heard and colleagues show that mouse XCI differs significantly from rabbit and human XCI.
Overall the study highlights the remarkable diversity in X-inactivation regulation, probably reflecting the changing nature of developmental processes during evolution.
CONTACT
Edith Heard (Institut Curie, Paris, France)
Tel: +33 1 56 24 66 91; E-mail: Edith.Heard(at)curie.fr
ALSO IN THIS ISSUE…
[7] Streptococcal M1 protein constructs a pathological host fibrinogen network (pp 64-68)
[8] Evidence for mechanical coupling and strong Indian lower crust beneath southern Tibet (pp 79-81N&V)
[9] Dampening of death pathways by schnurri-2 is essential for T-cell development (pp 105-109)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 06 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 07 April, but at a later date. ***
[10] DISC1-dependent switch from progenitor proliferation to migration in the developing cortex
DOI: 10.1038/nature09859
[11] Thermal history of Mars inferred from orbital geochemistry of volcanic provinces
DOI: 10.1038/nature09903
[12] Crystal structure of a phosphorylation-coupled saccharide transporter
DOI: 10.1038/nature09939
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
St Lucia: 7
FRANCE
Dijon: 7
Grenoble: 7
Jouy en Josas: 7
Paris: 6
Toulouse: 11
GERMANY
Munich: 12
JAPAN
Kobe: 1
Kyoto: 1
Suita: 1
Tokyo: 10
Tsukuba: 9
Wako: 1
SWITZERLAND
Zurich: 7
UNITED KINGDOM
Cambridge: 8
Glasgow: 10
UNITED STATES OF AMERICA
California
La Jolla: 7, 12
Los Angeles: 2
Pasadena: 8
Illinois
Argonne: 12
Maryland
Baltimore: 10
Massachusetts
Boston: 9
Cambridge: 5
Charlestown: 9
North Grafton: 5
Michigan
Ann Arbor: 3
New York
New York: 12
Yorktown Heights: 4
North Carolina
Chapel Hill: 5
Durham: 10
Ohio
Cleveland: 2
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From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: m.nakano(at)natureasia.com
From the UK
Rebecca Walton, Nature, London
Tel: +44 20 7843 4502; E-mail: r.walton(at)nature.com
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