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Article Released Wed-9th-August-2006 17:01 GMT
Contact: Ruth Institution: Nature Publishing Group
 Submersible rice offers crop safeguard against flood

Summaries of newsworthy papers from Nature. Frozen rocks spotted by X-ray blocking, New technique glimpses half-billion-year-old embryos, Egg donation, compensation and regulation, The case of the missing lithium may be solved, Watching a crystal shake with light, Controlling the super-traffic, Origins of body patterning


This press release is copyright Nature. VOL.442 NO.7103 DATED 10 AUGUST 2006

This press release contains:

· Summaries of newsworthy papers:

- Genetics: Submersible rice offers crop safeguard against flood

- Astronomy: Frozen rocks spotted by X-ray blocking

- Palaeontology: New technique glimpses half-billion-year-old embryos

- Stem cells: Egg donation, compensation and regulation

- Stellar Chemistry: The case of the missing lithium may be solved

- Optics: Watching a crystal shake with light

- Quantum physics: Controlling the super-traffic

- Genetics: Origins of body patterning

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

· Geographical listing of authors

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[1] Genetics: Submersible rice offers crop safeguard against flood (pp 705-708; N&V)

Geneticists have identified a gene that allows rice plants to survive complete submersion in water for up to two weeks. Introducing this gene into other strains of rice could offer much-needed protection against flooding in paddy fields, which can destroy vulnerable crops.

Most rice cultivars (Oryza sativa) die within a week of complete submersion — such flooding costs farmers in south and southeast Asia more than US$1 billion a year. But some cultivars are highly tolerant, by virtue of a genetic sequence called Sub1 on one of their chromosomes.

David Mackill and his colleagues have discovered a gene variant called Sub1A-1 within this region that specifically confers resistance to flooding. Introducing this gene variant into previously vulnerable rice strains allows them to withstand a soaking, they report in this week’s Nature.


David Mackill (International Rice Research Institute, Manila, Philippines)
Tel: + 63 2580 5600; E-mail:

Takuji Sasaki (National Institute of Agrobiological Sciences, Ibaraki, Japan)
Tel: + 81 29 838 7097; E-mail:

[2] Astronomy: Frozen rocks spotted by X-ray blocking (pp 660-663; N&V)

Frozen chunks of rock in the outer reaches of the Solar System can be spotted when they obscure starlight, astronomers report in this week's Nature.

Almost a thousand trans-neptunian objects (TNOs), found beyond the orbit of the planet Neptune, have been seen with conventional telescopes. The size distribution of these frosty remnants gives astronomers important clues about the formation of the Solar System. But direct observation is only possible for TNOs bigger than a few tens of kilometres across.

Hsiang-Kuang Chang and colleagues now report that they have identified 58 TNOs smaller than 100 metres across, by looking at X-rays coming from the star Scorpius X-1. As the TNOs move, they block the line of sight of NASA's orbiting telescope, the Rossi X-ray Timing Explorer, for a few milliseconds while it looks at Scorpius. That's long enough to identify the objects and estimate their size, the scientists say.


Hsiang-Kuang Chang (National Tsing Hua University, Hsinchu, Taiwan)
Tel: +886 35 74 29 52; E-mail:

Asantha Cooray (University of California, Irvine, CA, USA)
Tel: +1 949 824 6832; E-mail:

[3] Palaeontology: New technique glimpses half-billion-year-old embryos (pp 680-683)

Palaeontologists have ushered in a revolution in their field, with the first detailed visualization of the structures of tiny fossilized embryos dating back to the very dawn of multicellular life. Using a technique called synchrotron-radiation X-ray tomography (SRXTM), researchers have picked out the features of tiny unborn creatures from more than 500 million years ago.

Previous attempts to study such fossils were hampered by a reliance either on finely slicing the specimens, giving only a two-dimensional view, or simply studying their exteriors only. Using the new method, Philip Donoghue and his colleagues give the first three-dimensional glimpse inside these embryos, found in China and Siberia, which are less than a millimetre across and are members of worm-like ancient species called Markuelia and Pseudooides.

The advance is of similar significance to that brought about several decades ago by the advent of the electron microscope, the researchers write in this week's Nature. Viewing the finer points of embryological development allows minute differences between related species to be resolved, and should be suitable for a wide range of similar fossilized structures.

Philip Donoghue (University of Bristol, UK)
Tel: +44 117 954 5440; E-mail:

Please note the author is travelling and it may be easier to contact him on his mobile phone:
Mobile: +44 7941 857 881

Stem cells: Egg donation, compensation and regulation (pp 629-630)

Women who donate their eggs for stem cell research should be compensated in the same way as other healthy research volunteers, according to a Commentary in Nature this week. Insoo Hyun argues that most volunteers participating in biomedical research are compensated when there are no direct benefits to them, and that these women should be remunerated in the same way.

Egg donation is demanding of women’s energy and time; some giving up as many as 40 hours to provide eggs for research. They endure painful hormone injections, often with unpleasant side effects, and their eggs are retrieved via a minor surgical procedure.

Some ethicists are concerned that offering money for egg donation could undermine informed consent, by creating an undue inducement to donate; however, Hyun argues that regulating the process presents the perfect opportunity to reduce such risks. Furthermore, he believes that even in the absence of compensation, informed consent can be impaired, as was the case with several women who donated to Woo Suk Hwang’s research.

Currently, the International Society for Stem Cell Research (ISSCR) is planning public consultations surrounding egg donation for research purposes. Hyun believes that ethical guidelines should recognize what women endure when donating their eggs, and that local ethical review bodies should decide how best to determine compensation levels and ensure a well monitored recruitment and informed consent process.


Insoo Hyun (Case Western Reserve University, Cleveland, OH, USA)
Tel: +1 216 368 8658; E-mail:

[4] Stellar chemistry: The case of the missing lithium may be solved (pp 657-659; N&V)

There doesn't seem to be as much lithium in the Universe as there ought to be. In Nature this week, an international team of astronomers try to explain where it all went.

The problem is that old stars, which ought to be made from a mixture of elements close to the 'primordial' blend generated in the Big Bang, don't appear to have as much lithium as this would require. Although most of the matter produced by the Big Bang was hydrogen and helium, theories of element production predict that there should also be a fair proportion of lithium. But the amount predicted is a factor of two or three times larger than that seen in old stars. This implies that our understanding of the physics either of the Big Bang or of stars - or both - is lacking.

Andreas Korn and colleagues look at 18 stars in a cluster of old stars to see how the elemental content of their atmospheres changes with evolutionary stage. They find that various elemental abundances depend on a star's temperature. This, the researchers say, is because heavy elements tend to diffuse deep into the star. For those stars that have evolved into giants, the elements are mixed back into the stellar atmosphere by convection, so that the stars' composition is restored. Not so for lithium: it does not survive the trip through the stellar interior, as it is burnt when temperatures exceed 2 million degrees.

Korn and colleagues estimate that the original lithium abundance in these stars was around 78 percent higher than that suggested by current average values - which is enough to make up the discrepancy with the predicted primordial abundance.


Andreas Korn (Uppsala Astronomical Observatory, Sweden)
Tel: +46 184 715 994; E-mail:

Corrine Charbonnel (Observatoire Midi-Pyrenees, Toulouse, France)
Tel: +33 5 61 33 27 87; E-mail:

[5] Optics: Watching a crystal shake with light (pp 664-666)

In this week’s Nature, researchers watch light riding through a crystal on the back of vibrations of the atomic lattice. These light signals coupled to atomic motions are known as polaritons. Andrea Cavalleri and colleagues use X-rays in a lithium tantalate crystal to see the coordinated vibrations of its ions, linked to the passage of particles of low-frequency light called terahertz radiation.

Lithium tantalate is a material in which an electric field induces a change in the positions of the ions that make up the crystal. It is this behaviour that creates the coupling of vibrations in the ion lattice to the oscillating electromagnetic fields of light waves. The lattice vibrations can be induced by shining a laser pulse onto the crystal. As the lattice oscillates, this sets up a fluctuating electromagnetic field which takes the form of a light polariton with a frequency close to that of the lattice vibration: at terahertz frequencies, lower than infrared but higher than microwaves.

The researchers watch the ion vibrations by bouncing very short pulses of X-rays off the crystal. In X-ray crystallography, the pattern of X-rays scattered from a crystal reveals the average positions of the atoms. In this experiment, the pulsed X-ray beam allows the changes in the atomic positions as a result of vibration to be seen. This is the first time that such polariton-linked vibrations of a crystal have been tracked directly.


Andrea Cavalleri (University of Oxford, UK)
Tel: +44 1865 272 365; E-mail:

[6] Quantum physics: Controlling the super-traffic (pp 667-670)

If you want an electrical current to reverse the direction in which it flows rounds a circuit, you have to switch the voltage driving it — by, for example, putting in the battery the other way round. But in Nature this week researchers show that in a quantum-mechanical circuit — a superconducting quantum interference device (SQUID) — the current can be reversed by far subtler means: specifically, by placing a single electron on a 'weak link' where the current has to jump across a kind of barrier.

In the SQUID made by Leo Kouwenhoven and colleagues, the current circulates around a ring-shaped circuit made from microscopic aluminium wire. There are two breaks in this loop, each of them bridged by much narrower wires, just 60 nanometres wide and made from the semiconductor indium arsenide. At very low temperatures — about a degree above absolute zero — the aluminium becomes superconducting, and the current is carried by pairs of electrons moving in concert, with zero electrical resistance. The nanowires form weak links, like bottlenecks, in the circuit.

The team have used electric fields to turn the semiconductor nanowires into 'quantum dots' — isolated islands of electrical charge. Electron pairs can jump to and from the islands, so that the supercurrent becomes 'chopped' into discrete parcels of two electrons. But by adding a single electron to the quantum dot, the researchers found that they could reverse the direction of the supercurrent: it is as if the electron acts as a traffic controller, sending the superconducting electron pairs in the opposite direction.


Leo Kouwenhoven (Delft University of Technology, Netherlands)
Tel: +31 15 278 6064; E-mail:

Please note the author is travelling and it may be easier to reach Jorden van Dam
Tel: +31 15 278 6085; E-mail:

[7] Genetics: Origins of body patterning (pp 684-687)

Hox and ParaHox genes have a key role in the development of bilateral animals by helping to determine the layout of the main body axis. But the evolutionary history of these genes is uncertain. A paper in this week’s Nature now suggests that the Hox/ParaHox precursor was simpler than originally thought.

Daniel Chourrout and colleagues studied Hox/ParaHox genes in a sea anemone (Nematostella vectensis) and a freshwater polyp (Hydra magnipapillata). Both creatures are members of the Cnidaria phylum, the sister group to bilateral animals, so their genetic makeup can be used to help reconstruct the early history of Hox/ParaHox genes.

The team think that the common ancestor of cnidarians and bilaterians contained relatively uncomplicated versions of the Hox and ParaHox clusters, and that the Hox/ParaHox precursor — ProtoHox — contained just two anterior genes to specify the front end of the body. Non-anterior genes, they suggest, evolved later, possibly after the bilaterian and cnidarian family trees split.


Daniel Chourrout (University of Bergen, Norway)
Tel: +47 55 58 43 13; E-mail:


[8] Card9 controls a non-TLR signaling pathway for innate anti-fungal immunity

[9] Arctic hydrology during global warming at the Palaeocene/Eocene thermal maximum

[10] The dynamics of melt and shear localization in partially molten aggregates


***This paper will be published electronically on Nature's website on 09 August 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 10 August, but at a later date.***

[11] Nutrient regulates Tor1 nuclear localization and association with rDNA promoter
DOI: 10.1038/nature05020

[12] The emergence of geometric order in proliferating metazoan epithelia
DOI: 10.1038/nature05014


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.

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Munich: 8

Trieste: 6

Bergen: 7

Manila: 1

Moscow: 4

Uppsala: 4

Villigen: 3

Hsinchu: 2
Taipei: 2

Delft: 6
Eindhoven: 6
Texel: 9
Utrecht: 9

Bristol: 3
Liverpool: 3
Oxford: 5

Berkeley: 5
Davis: 1
Irvine: 7
Oakland: 7
Riverside: 1

New Haven: 9

West Lafayette: 9

Boston: 12
Cambridge: 5, 12

Kansas City: 12
St Louis: 11

New Jersey
Piscataway: 11

New York
Palisades: 10

Houston: 9

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Rinoko Asami, Nature Tokyo
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Keywords associated to this article: Genetics, Submersible rice, flood, Astronomy, Frozen rocks, X-ray, Palaeontology, embryos, Stem cells, Egg donation, compensation, regulation, Stellar Chemistry, lithium, Optics, crystal, Quantum physics, body
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