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Article Released Wed-29th-July-2009 17:15 GMT
Contact: Ruth Institution: Nature Publishing Group
 Obesity: A recipe for ‘good’ fat

Newsworthy papers include Northern peatlands contribute to climate change, A new spin on Saturn’s atmosphere, The making of dwarf galaxies, Looking for clues to extending life, Alzheimer’s gene linked to neurotransmitter release, Chromosomes, know your place, Moving the oceans, one jellyfish at a time

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This press release is copyright Nature.

VOL.460 NO.7255 DATED 30 JULY 2009

This press release contains:

· Summaries of newsworthy papers:

Obesity: A recipe for ‘good’ fat

Climate change: Northern peatlands contribute to climate change

Planetary science: A new spin on Saturn’s atmosphere

Astronomy: The making of dwarf galaxies

Ageing: Looking for clues to extending life

Neuroscience: Alzheimer’s gene linked to neurotransmitter release

Genetics: Chromosomes, know your place

Early Earth: Arrival of the late veneer and mantle mixing

And finally… Moving the oceans, one jellyfish at a time

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

· Geographical listing of authors


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[1] Obesity: A recipe for ‘good’ fat (AOP)
DOI: 10.1038/nature08262

***This paper will be published electronically on Nature's website on 29 July 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 30 July, but at a later date. ***

The recipe for brown fat formation is described online this week in Nature. Brown fat specializes in burning calories to generate body heat, in contrast to white fat which acts as an energy store. It’s hoped that the findings could pave the way for new approaches to combat metabolic disorders such as obesity and type-2 diabetes.

Bruce Spiegelman and colleagues reported in Nature last year that brown fat cells are closely related to skeletal muscle, and that the protein PRDM16 can instruct muscle stem cells to become brown fat cells. The team now dissect the mechanism further and show that PRDM16 acts together with another protein, C/EBP-beta, to switch on the expression of PPARgamma — a regulator of fat formation.

Using this recipe, the team created fully functional brown fat cells in the lab from both mouse and human stem cells. When transplanted into mice, the mouse cells formed a brown ‘fat pad’ that acted as a glucose ‘sink’, soaking up extra energy.

Although further experiments are needed to assess how the transplanted cells expend the extra energy they take up, the researchers are optimistic that their recipe could one day be used to drive brown fat development in a therapeutic setting.

CONTACT
Bruce Spiegelman (Harvard Medical School and Dana-Farber Cancer Institute, Boston, MA, USA)
Tel: +1 617 632 3567; E-mail: bruce_spiegelman@dfci.harvard.edu


[2] Climate change: Northern peatlands contribute to climate change (pp 616-619)

Global warming is accelerating the release of carbon dioxide from subsurface peatlands in the subarctic, a Nature paper suggests.

Around one-third of the world’s soil organic carbon is stored in northern peatlands, raising concerns that global warming could boost respiration of thick, old peat deposits, and accelerate carbon dioxide release into the atmosphere. Ellen Dorrepaal and colleagues show that a warming of around one degree celsius accelerates total ecosystem respiration rates by up to 60 per cent and that the effect can last for at least eight years.

This is greater than was previously thought, highlighting the extreme sensitivity of northern peatland carbon reservoirs to climate warming. The findings suggest an important, long-lasting positive feedback of carbon stored in northern peatlands to the global climate system.

CONTACT
Ellen Dorrepaal (Vrije University, Amsterdam, Netherlands)
Tel: +31 6 22 23 16 02; E-mail: ellen.dorrepaal@ecology.falw.vu.nl


[3] Planetary science: A new spin on Saturn’s atmosphere (pp 608-610; N&V)

A new way of estimating Saturn’s rotation rate is reported in this week’s Nature. The result offers a solution to a long-standing puzzle regarding the winds of Saturn and Jupiter, and sheds light on Saturn’s deep interior.

Like the rocky planets, gas giant planets such as Jupiter and Saturn spin on their axes with well defined rotation periods. But, with no solid surface features to track, measuring the rotation period of a gas giant is a challenge. The approach that has worked for Jupiter, Uranus and Neptune — using the rotation of the planet’s magnetic field to infer its bulk rotation — gives results for Saturn that change with time, and implies a pattern of atmospheric winds that is very different from that seen on Jupiter.

Peter Read and colleagues use a new approach, based on an analysis of atmospheric dynamics, to derive a rotation rate for Saturn that is faster than those inferred from magnetic measurements. When Saturn’s atmospheric winds are viewed relative to this new interior reference frame, they show a pattern of alternating eastward and westward jets similar to the pattern seen on Jupiter. The new rotation rate also places important constraints on Saturn’s interior structure, including its density and the mass of a possible rocky core.

CONTACT
Peter Read (University of Oxford, UK)
Tel: +44 1865 272082; E-mail: p.read1@physics.ox.ac.uk

Adam Showman (University of Arizona, Tucson, AZ, USA) N&V author
Tel: +1 520 621 4021; E-mail: showman@lpl.arizona.edu


[4] Astronomy: The making of dwarf galaxies (pp 605-607)

An explanation for the origin of dwarf spheroidal galaxies is offered in a study published this week in Nature. The research may settle an outstanding puzzle in understanding galaxy formation.

Dwarf spheroidal galaxies have very low luminosity. They contain little gas and have very few stars relative to their dark matter content, which has made it difficult for astronomers to explain their origin. Previous theories require that dwarf spheroidals orbit near giant galaxies like the Milky Way, but this does not explain how dwarfs that have been observed in the outskirts of the ‘Local Group’ of galaxies could have formed.

Elena D’Onghia and colleagues report simulations of encounters between dwarf disk-shaped galaxies and larger dwarfs. They find that the encounters excite a gravitational process which they term 'resonant stripping', leading to the removal of stars from the smaller dwarf over the course of the interaction and transforming it into a dwarf spheroidal. According to their model, dwarf spheroidals should form and interact in pairs or small groups, thereby leaving long stellar streams that should be detectable.

CONTACT
Elena D’Onghia (University of Munich, Germany)
Tel: +49 89 21806034; E-mail: donghia@usm.uni-muenchen.de


[5] Ageing: Looking for clues to extending life (pp 587-591)

Though they are known to prolong lifespan in lower organisms, the role of sirtuin enzymes in mammals is unknown. In this week’s Nature, Toren Finkel and colleagues discuss recent progress in mammalian sirtuin research and what role these enzymes may have in age-related diseases and how long we live.

Sirtuins are a highly conserved family of enzymes found in organisms that range from yeasts to humans. Members of this family were originally shown to prolong the lifespan of yeast cells by regulating DNA repair and gene transcription. Toren Finkel and colleagues discuss how in mice these enzymes have a significant role in cellular stress resistance and cell death, though no link has yet been found between sirtuins and prolonged lifespan in mice. The review also discusses metabolic studies and the role of sirtuins in glucose homeostasis and insulin secretion — which implies that they may also play a part in regulating susceptibility to insulin resistance and diabetes.

These studies open the door to future studies on the role of sirtuins in cellular regulation and postponement of cellular ageing.

CONTACT
Toren Finkel (National Heart, Lung and Blood Institute, Bethesda, MD, USA)
Tel: +1 301 402 4081; E-mail: finkelt@nih.gov


[6] Neuroscience: Alzheimer’s gene linked to neurotransmitter release (pp 632-636)

A gene best known for its link to Alzheimer’s disease is now shown to be essential for regulating neurotransmitter release. The finding, reported in this week’s Nature, may help shed light on the early causes of dementia.

Mutations in the presenilin genes are the major cause of early onset, familial cases of Alzheimer’s disease, but where they operate and what they do in neurons has been unclear. Jie Shen and colleagues use mouse models to show that presenilins function on the presynaptic side of synapses between two communicating neurons.

The presynaptic compartment produces neurotransmitters, the brain’s chemical messengers, which are released into the synapse to relay information to neighbouring cells. The team shows that presenilins affect neurotransmitter release in a way that may affect learning and memory. Taken together, the findings suggest that presynaptic dysfunction might be an early cause of dementia in neurodegenerative disorders.

CONTACT
Jie Shen (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 525 5561; E-mail: jshen@rics.bwh.harvard.edu

Chen Zhang (Harvard Medical School, Boston, MA, USA) Co-author paper [6]
Tel: +1 617 525 5741; E-mail: czhang@rics.bwh.harvard.edu


[7] Genetics: Chromosomes, know your place (AOP)
DOI: 10.1038/nature08217

***This paper will be published electronically on Nature's website on 29 July 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 30 July, but at a later date. ***

A catalogue of factors that help to keep the order of genes on chromosomes ‘in their place’ and so prevent genomic instability is revealed in this week’s Nature.

The human genome contains many types of repeated ‘at risk’ sequences that are inherently unstable and can undergo genomic rearrangements. The cell uses various proteins to ensure that such rearrangements do not occur often. Richard Kolodner and colleagues provide a comprehensive analysis of factors involved in suppressing large-scale chromosomal rearrangements.

They find, surprisingly, that these repetitive at-risk sequences use a pathway to suppress rearrangements that is distinct from that used to stabilize single-copy sequences. This study helps explain how genomes manage to remain stable despite containing many types of at-risk sequences.

CONTACT
Richard Kolodner (Ludwig Institute for Cancer Research, La Jolla, CA, USA)
Tel: +1 858 534 7804; E-mail: rkolodner@ucsd.edu


[8] Early Earth: Arrival of the late veneer and mantle mixing (pp 620-623; N&V)

The timing of the bombardment of meteorites onto the early Earth and the progressive mixing of this material into the mantle can be constrained by the composition of ancient komatiite eruptions, suggests a report in Nature this week. The findings may provide important constraints on the timescale of mantle convection and compositional evolution of the early Earth.

It is thought that most of the original platinum-group elements in the early Earth were sequestered into the core soon after formation, and that these elements were later replenished during a period of meteorite impacts, some time between 4.5 and 3.8 billion years ago, during the ‘late heavy bombardment’. Wolfgang Maier and colleagues trace the history of platinum-group elements in the mantle by analysing samples of komatiites from South Africa and Western Australia. These are some of the oldest volcanic rocks on Earth, thought to sample the deep mantle.

The results show that the oldest, 3.5-billion-year-old, komatiites are depleted in platinum-group elements owing to early core formation, but that the signal gradually increases over time. The authors infer that this pattern arises as the ‘late veneer’ from the meteorite bombardment was gradually mixed into the mantle, with the mantle only attaining its present platinum-group-element content some 2.7 billion years ago. The finding overturns previous assumptions about rapid incorporation of the late veneer into the mantle.

CONTACT
Wolfgang Maier (University of Western Australia, Perth, Australia)
Tel: +61 8 6488 2771; E-mail: wdmaier@cyllene.uwa.edu.au

Nicholas Arndt (University of Grenoble, St Martin d'Heres, France) N&V author
Tel: +33 4 76 63 59 31; E-mail: arndt@ujf-grenoble.fr


[9] And finally… Moving the oceans, one jellyfish at a time (pp 624-626; N&V)

Swimming jellyfish, together with other aquatic creatures, significantly contribute to ocean turbulence and nutrient transport as reported online in this week’s Nature.

The ongoing debate about ocean mixing is centred on how much wind and tides contribute to ocean turbulence and how much is caused by the movement of aquatic animals. Sir Charles Darwin — grandson of the eminent evolutionary biologist — first described a mechanism for fluid mixing that depended on the movement of solid bodies. Darwin’s mechanism took into account the size and shape of the moving body rather than simply its motion.

Kakani Katija and John Dabiri tested Darwin’s mechanism by observing the ocean turbulence caused by swimming jellyfish in the Pacific Ocean. They found that the size and shape of jellyfish was important in how its movements contributed to ocean mixing. Extrapolation of these findings showed that aquatic creatures contributed to ocean mixing in the same order of magnitude as winds and tides.

CONTACT
Kakani Katija (California Institute of Technology, Pasadena, CA, USA)
Tel: +1 626 395 4462; E-mail: kakani@caltech.edu

John Dabiri (California Institute of Technology, Pasadena, CA, USA)
Tel: +1 626 395 6294; E-mail: jodabiri@caltech.edu

William Dewar (Florida State University, Tallahassee, FL, USA) N&V author
Tel: +1 850 644 4099; E-mail: wdewar@fsu.edu

ALSO IN THIS ISSUE…

[10] Crystal structure of the ATP-gated P2X4 ion channel in the closed state (pp 592-598; N&V)

[11] Pore architecture and ion sites in acid sensing ion channels and P2X receptors (pp 599-604; N&V)

[12] A ‘granocentric' model for random packing of jammed emulsions (pp 611-615)

ADVANCE ONLINE PUBLICATION

***This paper will be published electronically on Nature's website on 29 July 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 30 July, but at a later date. ***

[13] Riboflavin Kinase couples TNF Receptor 1 to NADPH oxidase
DOI: 10.1038/nature08206

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
Canberra: 8
Perth: 8

CANADA
Saguenay: 8:

FINLAND
Espoo : 8
Helsinki: 8
Oulu : 8

GERMANY
Cologne: 13
Kiel: 13

NETHERLANDS
Amsterdam: 2

SWEDEN
Abisko: 2

SWITZERLAND
Zurich: 4

UNITED KINGDOM
Edinburgh: 2
Sheffield: 2
York: 2

UNITED STATES OF AMERICA

California
La Jolla: 7
Los Angeles: 3
Palo Alto: 6
Pasadena: 9

Kentucky
Louisville: 3

Maryland
Bethesda: 5

Massachusetts
Boston: 1, 5, 6
Cambridge: 4

New York
New York: 12

Oregon
Portland: 10, 11

Tennessee
Memphis: 6

PRESS CONTACTS…

From North America and Canada
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Tel: +1 212 726 9231; E-mail: n.afsarmanesh@natureny.com

Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: k.mcgoldrick@naturedc.com

From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: m.nakano@natureasia.com

From the UK/Europe/other countries not listed above
Jen Middleton, Nature London
Tel: +44 20 7843 4502; E-mail j.middleton@nature.com

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