How the Earth's wobble makes mammals go extinct

Vaccinating the Ethiopian wolf, Titan's ocean lost forever?, Oxygen puzzle solved?, Modelling the early Universe, Controlling the insulin-degrading enzyme may relieve Alzheimer’s disease, Towards a quantum network and finally… Salamanders see red


This press release is copyright Nature.

VOL.443 NO.7112 DATED 12 OCTOBER 2006

This press release contains:

· Summaries of newsworthy papers:

Extinction: How the Earth's wobble makes mammals go extinct

Conservation: Vaccinating the Ethiopian wolf

Astronomy: Titan's ocean lost forever?

Earth sciences: Oxygen puzzle solved?

Particle physics: Modelling the early Universe

Biology: Controlling the insulin-degrading enzyme may relieve Alzheimer’s disease

Physics: Towards a quantum network

And finally… Salamanders see red

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

· Geographical listing of authors

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[1] Extinction: How the Earth's wobble makes mammals go extinct (pp 687-691)

Wobbles in the Earth’s orbit may be responsible for the puzzling regularity with which new mammalian species appear and then go extinct in the fossil record. Palaeontologists have surveyed some 22 million years' worth of fossil data, and show that peaks of species turnover seem to correspond to changes in the Earth’s orbit that produce global cooling.
Jan van Dam and colleagues studied the fossil record of rodents in Spain, which provides a detailed account of when these species rose and fell. As they report in Nature, the rate of species turnover showed a complex pattern consisting of two different cycles — a longer one with peaks roughly every 2.5 million years, and a shorter one that peaked every 1 million years.

What’s more, the timing of these peaks mirrors oscillations in the Earth’s behaviour — peaks roughly every 2.5 million years occur at times when the Earth’s orbit is closer to being a perfect circle, whereas 1-million-year peaks come at times when the Earth is shifting its degree of tilt on its axis. Both of these processes result in ice-sheet expansion, global cooling and changes to precipitation patterns, which may explain the previously puzzling observation that mammalian species tend to survive for an average of 2.5 million years before being snuffed out.


Jan van Dam (Utrecht University, Netherlands)
Tel: +31 302 535 178; E-mail: [email protected]

[2] Conservation: Vaccinating the Ethiopian wolf (pp 692-695)

Researchers have mapped out a vaccination strategy to protect the endangered Ethiopian wolf, Canis simensis, from rabies. They present their strategy in this week’s Nature.

The Ethiopian wolf is the world’s rarest dog. Several subpopulations live in the Bale Mountains of Ethiopia, connected by narrow corridors of habitat. Two large rabies outbreaks were detected in 1992 and 2003, and the dogs remain threatened by future outbreaks.

But the high level of vaccination required to eliminate rabies in an endangered population can be impractical and require potentially undesirable intervention. It’s thought that wildlife populations can tolerate limited outbreaks of disease. So rather than focusing on eliminating rabies entirely, Dan Haydon and colleagues focus on protecting the endangered Ethiopian wolf from extinction.

They aim to control the spread of disease through habitat corridors between subpopulations using only low vaccination coverage. This approach should reduce the extent of rabies outbreaks, and significantly enhance the long-term persistence of the population.


Dan Haydon (University of Glasgow, UK)
Tel: +44 141 330 6637; E-mail: [email protected]

[3] Astronomy: Titan's ocean lost forever? (pp 669-670)

When the Cassini-Huygens space probe touched down on Titan last year, it failed to find any evidence of the liquid ethane that was expected to be present on the surface. In this week's Nature, Donald Hunten explains why this ethane ocean is unlikely to exist.

Titan, Saturn's largest moon, has a dense atmosphere of nitrogen and methane. Its surface is hidden under thick orange-brown smog, produced as methane is dissociated by solar ultraviolet light. The most abundant product of this reaction is ethane, and scientists estimate that enough of it should have been generated over the life of the Solar System to form a satellite-wide ocean one kilometre deep.

Instead of condensing into liquid drops, Hunten believes that Titan's ethane condenses onto the dusty smog particles. This dusty combination of smog and ethane, which he dubs ‘smust’, forms deposits several kilometres thick on the satellite's surface.


Donald Hunten (University of Arizona, Tucson, AZ, USA)

Tel: +1 520 621 4002; E-mail: [email protected]

[4] Earth sciences: Oxygen puzzle solved? (pp 683-686; N&V)

Scientists may have solved a puzzling conundrum. In this week's Nature, they explain why there was a 300 million year gap between the evolution of oxygen-producing organisms and the first significant rise in atmospheric oxygen levels.

The so-called 'Great Oxidation' occurred some 2.4 billion years ago, paving the way for the dawn of multicellular life. Colin Goldblatt and colleagues used a modelling study to show that atmospheric oxygen levels could have remained at either a low or a high steady state after oxygen-producing photosynthesis first evolved. A relatively small environmental change, such as a small increase in net primary productivity, could then have triggered a switch between these states, causing oxygen levels to rocket.


Colin Goldblatt (University of East Anglia, Norwich, UK)
Tel: +44 1603 591 343; E-mail: [email protected]

James Kasting (Pennsylvania State University, PA, USA)

Tel: +1 814 865 3207; E-mail: [email protected]

[5] Particle physics: Modelling the early Universe (pp 675-678; N&V)

Researchers have characterized the moment, early in the history of the Universe, when the subunits of matter condensed into the familiar forms we know today.

The hot early Universe was a soup of quarks and gluons, but as the temperature dropped, these subunits became bound together to form protons and neutrons. Sandor Katz and colleagues have characterized this transition, inputting the real values of quark masses to help model the shift better.

In this week’s Nature, the team suggest that the transition was a rapid change rather than a jump, known as an analytic crossover. Unfortunately, this sort of transition is unlikely to leave an observable astronomical signature behind, so those wishing to find physical evidence of this transition may be disappointed.


Sandor Katz (Eotvos University, Budapest, Hungary)
Tel: +36 1 372 2747; E-mail: [email protected]

Frank Wilczek (MIT, Cambridge, MA, USA)
Tel: +1 617 253 0284; E-mail: [email protected]

[6] Biology: Controlling the insulin-degrading enzyme may relieve Alzheimer’s disease
(AOP; N&V)

DOI: 10.1038/nature05143

***This paper will be published electronically on Nature's website on 11 October 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 12 October, but at a later date.***

The structure of an enzyme that degrades insulin and amyloid-beta suggests a possible way to design drugs that combat the abnormal levels of these proteins in sufferers of diabetes or Alzheimer’s disease.

Insulin-degrading enzyme (IDE) is unusual because it binds and cleaves diverse substrates. In research to be published online by Nature this week, Wei-Jen Tang and his colleagues determine the structure of the enzyme in complex with four substrates, including a subunit of insulin or amyloid. They show that the enzyme undergoes a conformational change when it binds its substrate such that the two ends form an enclosed chamber shaped like a triangular prism. Small proteins that do not have significant positive charges at a certain end make better substrates.

Mutations that disrupt the interaction of the two ends of IDE promote the opening of the chamber to substrates and increase the rate of substrate breakdown 40-fold; hence, drugs similarly designed to disrupt the shape of IDE might help clear the accumulation of amyloid-beta that is characteristic of Alzheimer’s disease.


Wei-Jen Tang (University of Chicago, IL, USA)
Tel: +1 773 702 4331; E-mail: [email protected]

Dennis Selkoe (Harvard Medical School, Boston, MA, USA)

Tel: +1 617 525 5200; E-mail: [email protected]

[7] Physics: Towards a quantum network (pp 671-674)

In Nature this week, scientists announce a technological advance in the field of cavity quantum electrodynamics (CQED) — the interactions of light and matter. In CQED, the matter is as small as a single atom, trapped by light as faint as a single photon, resonating back and forth inside a tiny cavity. Each resonator cavity, with its trapped atom(s), could in theory act as a quantum information store connected via optical fibres to a large-scale quantum network, taking advantage of light and matter interactions.

For some years this delicate science has been restricted to technologically complex cavity resonators. But Jeff Kimble and colleagues demonstrate the first strong interaction between single atoms and photons confined to a toroid-shaped microresonator. Such resonators can be manufactured in large numbers on silicon chips, by standard lithography techniques.

The researchers drop chilled caesium atoms through the electric fields of microresonators arranged on a silicon wafer. The interaction between atom and resonator allows light — which had been blocked by coupling with a resonator mode — to pass through an optical fibre. This system is a proof-of-principle step toward the still distant targets of quantum networks, quantum logic gates, and quantum computing.


Jeff Kimble (California Institute of Technology, Pasadena, CA, USA)
Tel: +1 626 395 8340; E-mail: [email protected]

[8] And finally… Salamanders see red (p 649)

Salamanders may use a derivative of chlorophyll to help them detect red light, a Brief Communication in this week's Nature suggests.

Clint Makino and colleagues measured the absorbance spectra of individual light-sensitive rod cells taken from the eyes of tiger salamanders — Ambystoma tigrinum. When green-sensitive rod cells were incubated with the chlorophyll derivative chlorin e6, it rendered the cells as sensitive to red light as they are to green.

It is known that deep-sea dragon fish, which lack a red-sensitive visual pigment altogether, use a chlorophyll derivative in their green-sensitive rod cells in order to see deep red light. This co-opting of an accessory molecule to enhance red vision could therefore be a general phenomenon in vertebrate photoreception, the authors suggest.


Clint Makino (Massachusetts Eye & Ear Infirmary, Boston, MA, USA)
Tel: +1 617 573 4462; E-mail: [email protected]


[9] Phosphoinositides in cell regulation and membrane dynamics (pp 651-657)

[10] Origin of the dielectric dead layer in nanoscale capacitors (pp 679-682)


***This paper will be published electronically on Nature's website on 11 October 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 12 October, but at a later date.***

[11] Crystal structure of a rhomboid family intramembrane protease (N&V)

DOI: 10.1038/nature05255


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.

Changchun: 11

Robe: 2


Lyon: 1


Garching: 7

Munich: 1

Wuppertal: 5


Budapest: 5


Tokyo: 7


Auckland: 7

Dunedin: 7


Madrid: 1

Arusha: 2


Leiden: 1

Utrecht: 1


Edinburgh: 2

Glasgow: 2

Midlothian: 2, 4

Norwich: 4

Oxford: 2

Swansea: 2



Tuscon: 3

Los Angeles: 2

Pasadena: 7

Santa Barbara: 10

New Haven: 9, 11

Argonne: 6

Chicago: 6

Boston: 8
New York

New York: 8, 9


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From Japan, Korea, China, Singapore and Taiwan

Itsumi Kitahara, Nature Tokyo

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For the UK/Europe/other countries not listed above

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Published: 11 Oct 2006

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