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This press release is copyright Nature.
VOL.446 NO.7133 DATED 15 MARCH 2007
This press release contains:
* Summaries of newsworthy papers:
Developmental biology: Fruit flies shed light on blood cell development
Evolution: Fossil sheds light on middle ear evolution
Planetary science: The aftermath of a catastrophic collision
Plate tectonics: The shape and evolution of subduction zones
Quantum physics: Life history of a photon
Optics: Light fantastic
Seismology: Tracking tremor beneath Japan
And finally… Surprise addition to flowering plant family tree
* Mention of papers to be published at the same time with the same embargo
* Geographical listing of authors
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[1] & [2] Developmental biology: Fruit flies shed light on blood cell development (pp 320-324; 325-328)
Researchers have shown that a signalling centre in the fruitfly lymph gland controls the maintenance of blood cell precursors. The findings suggest that Drosophila could prove a useful model for studying blood development and immunity.
Blood precursor cells yield all of the different cells found in the blood system. In fruitflies, at least, this system is controlled by signals generated in part of the lymph gland called the posterior signalling centre (PSC), two Nature papers report. Signalling occurs via the JAK/STAT and Notch pathways, already well known for their roles in cell proliferation and differentiation, teams lead by Utpal Banerjee and Michele Crozatier report. And the PSC starts to form early in embryonic development.
Drosophila is relatively easy to modify genetically and so widely used in research. Modification of the genes highlighted in these papers is likely to shed light on the mechanics of blood development. And Drosophila studies also yield the prospect of direct in vivo imaging of blood cell precursors interacting with their stem cell niche.
CONTACT
Utpal Banerjee (University of California, Los Angeles, CA, USA) Author paper [1]
Tel: +1 310 206 5439; E-mail: [email protected]
Please note the author is travelling until 12 March, but should have email access before then.
Michele Crozatier (CNRS-Centre de Biologie du Developpement, Toulouse, France) Author paper [2]
Tel: +33 5 61 55 82 90; E-mail: [email protected]
[3] Evolution: Fossil sheds light on middle ear evolution (pp 288-293)
The three tiny bones found in the mammalian middle ear are known to have evolved from components of the reptilian lower jaw. But the transition can now be seen in fossil form.
In this week’s Nature, Zhe-Xi Luo and colleagues describe the fossilized remains of a primitive mammal that probably lived around 125 million years ago. The animal’s middle-ear bones remain connected to the lower jaw by Meckel’s cartilage, and the transition to the mammalian state is associated with a corresponding remodelling of the lower back region.
But the situation is not as clear-cut as it seems. The evolutionary relationships of the fossil suggest that either the modern-style middle ear evolved independently twice, or evolved and then was lost in at least one ancient lineage.
CONTACT
Zhe-Xi Luo (Carnegie Museum of Natural History, Pittsburgh, PA, USA)
Tel: +1 412 622 6578; E-mail: [email protected]
Leigh Kish (Media Contact, Carnegie Museum of Natural History, Pittsburgh, PA, USA)
Tel: +1 412 578 2571; E-mail: [email protected]
[4] Planetary science: The aftermath of a catastrophic collision (pp 294-296; N&V)
Scientists have discovered a new family of bodies in the Kuiper belt that they think are the remnants of a catastrophic collision with the belt's third largest object, 2003 EL61. The discovery may have implications for understanding the dynamics of the outer Solar System and the surfaces of Kuiper belt objects.
Michael E. Brown and colleagues found bodies with similar surface properties and orbital dynamics to the dwarf-planet-sized object 2003 EL61. From this, they inferred that something hit this large Kuiper belt object and created a family of objects, along with its satellite system.
There are many families of asteroids in the main asteroid belt that are the remnants of a catastrophic impact. But in the region beyond Neptune, no collisionally created families have hitherto been found. The newly spotted objects are probably fragments of the ejected ice mantle of 2003 EL61.
CONTACT
Michael E. Brown (California Institute of Technology, Pasadena, CA, USA)
Tel: +1 626 395 8423; E-mail: [email protected] <mailto:[email protected]>
Alessandro Morbidelli (Laboratoire Cassiopee, Nice, France) N&V author
Tel: +33 4 92 00 31 26; E-mail: [email protected]
[5] Plate tectonics: The shape and evolution of subduction zones (pp 308-311)
A report in this week’s Nature presents an analysis of subduction zones - one of the most important features of plate tectonics - and reveals the factors that affect their migration velocities and how their shape changes with time. The study explains the curvature of oceanic trenches and volcanic island arcs and presents a possible explanation for mountain building in the Andes.
Subduction zones are found where one of the Earth’s tectonic plates plunges down beneath another into the mantle - often with a denser oceanic plate being subducted beneath the lighter, more buoyant, continental crust. Wouter P. Schellart and colleagues developed a three-dimensional numerical model of mantle dynamics, and found that the width of the subducting slab and the distance from the edge of the subduction zone control both the curvature and the retreat velocity of the trench.
The team show that maximum trench retreat velocities are only observed close to slab edges, and that far from edges the retreat velocities are always slow. They find that very wide slabs are nearly stationary in the centre and develop a convex geometry. Narrow slabs, on the other hand, retreat much faster and develop a more concave geometry. They also suggest that the model may explain mountain building in the central Andes as a consequence of being far from a slab edge - mountain building in the region has presented an enigma because the South American plate borders a subduction zone rather than a continental collision zone such as in the Himalayas.
CONTACT
Wouter P. Schellart (The Australian National University, Canberra, Australia)
Tel: +61 2 6125 9959; E-mail: [email protected]
[6] Quantum physics: Life history of a photon (pp 297-300; N&V)
Physicists have 'watched' the birth, life and death of a single photon in real time. Their clever technique, described in this week's Nature, allows single light quanta to be continuously monitored without destroying them, and may help those who wish to study the quantum-to-classical boundary.
Microscopic quantum systems can unexpectedly jump between states - an atom, for example, can change from its ground state to an excited one. Physicists have detected the quantum jumps of electrons, ions and other particles, but have struggled to see the effect in photons, which are usually destroyed when measured.
Michel Brune and colleagues have got round this problem by storing photons in a superconducting cavity. The photons were continually probed by a stream of non-absorbing rubidium atoms, allowing the team to detect and monitor single light quanta. The times when a photon suddenly appears and disappears reveal the random quantum jumps of light. And the experiment realizes Einstein's dream of storing a single photon in a box for times in the second range.
CONTACT
Michel Brune (Laboratoire Kastler Brossel, Paris, France)
Tel: +33 1 44 32 33 65; E-mail: [email protected]
Serge Haroche (Laboratoire Kastler Brossel, Paris, France) Co-author
Tel: +33 1 44 32 34 20
Jean-Michel Raimond (Laboratoire Kastler Brossel, Paris, France) Co-author
Tel: +33 1 44 32 34 88
Ferdinand Schmidt-Kaler (University of Ulm, Germany) N&V author
E-mail: [email protected]
[7] Optics: Light fantastic (pp 301-304)
The size of a mechanical tool usually limits its spatial resolution, an example being a drill that cannot make holes smaller than its own diameter. But in this week's Nature, researchers unveil just such a resolution-busting feat performed with light.
The ‘shaping’ of fundamental properties of very fast laser pulses is already widely used to control how light waves interfere with one another and with other quantum systems - so-called ‘coherent control’. But it’s hard to control interference to a point much finer than the wavelength of the laser light. Tobias Brixner and colleagues have now extended the coherent control method to make it possible to control how light interacts with matter at spatial resolutions much smaller than the wavelength of the light being used.
They achieve this by shining their laser pulses on nanometre-sized silver disks, which creates an optical near field. This approach is well known, but combining it with coherent control now allows the researchers to dictate the distribution of the optical field over the nanostructure and to switch between different distributions with high speed.
CONTACT
Tobias Brixner (Universit�t Wuerzburg, Germany)
Tel: +49 931 888 5705; E-mail: [email protected]
[8] Seismology: Tracking tremor beneath Japan (pp 305-307)
Non-volcanic tremor consists of swarms of small, low-frequency earthquakes (LFEs) caused by shear faulting at a plate boundary, according to a study in this week’s Nature.
Seismic tremor in volcanic regions is thought to be due to movements of magma, but the mechanisms involved in non-volcanic tremor are unclear. The tremor is also more difficult to locate than an earthquake because it lacks the impulsive body wave arrivals, which are normally used to pinpoint an earthquake’s position.
Gregory Beroza and colleagues studied tremor beneath Shikoku, Japan, where earthquakes are located at the interface of the subducting Philippine Sea plate at depths of 30-35 kilometres. They used the waveforms of previously recorded LFEs in the region as templates to see if they matched the tremor events. The technique revealed a nearly continuous sequence of LFEs during active tremor. The authors were therefore able to track the source of the tremor with unprecedented spatial and temporal resolution. They suggest that the method could prove useful in monitoring slow slip events, which may load adjacent portions of a fault, bringing it closer to failure.
CONTACT
Gregory Beroza (Stanford University, CA, USA)
Please contact co-author:
David Shelly (Stanford University, CA, USA)
Tel: +1 650 723 6658; E-mail: [email protected]
[9] And finally… Surprise addition to flowering plant family tree (pp 312-315; N&V)
Biologists have added a new addition to the base of the flowering plant family tree. The classification, reported in this week’s Nature, should help those trying to fathom the evolutionary history of angiosperms.
Hydatellaceae are a small, obscure family of aquatic herb usually reckoned to be flowering plants akin to grasses. But a new study of their anatomy and molecular biology by Sean W. Graham and co-workers now places them, surprisingly, next to the water lilies as among the most primitive flowering plants.
Although the relationship of flowering plants to other seed plants remains controversial, great progress has been made in identifying some of the most primitive members of the angiosperm family tree. These include water lilies, magnolias and the New Caledonian shrub Amborella trichopoda. The addition of Hydatellaceae at the same level should help biologists as they puzzle over the evolution of the distinctive reproductive structures whose appearance led to the dominance of flowering plants seen in modern ecosystems.
This week’s Nature also includes a package of features about Carl Linnaeus’ legacy as it applies to modern debates concerning conservation and taxonomy. Celebrating the 300th anniversary of Linnaeus’ birthday, the package also includes two commentaries on the future of Linnaean science - not to mention a portrait of his pet racoon.
CONTACT
Sean W. Graham (University of British Columbia, Vancouver, Canada)
Tel: +1 604 822 4816; E-mail: [email protected]
James A. Doyle (University of California Davis, CA, USA) Co-author
Tel: +1 530 752 7591; E-mail: [email protected]
Else Marie Friis (The Swedish Museum of Natural History, Stockholm, Sweden) N&V author
Tel: +46 8 5195 4155; E-mail: [email protected]
ALSO IN THIS ISSUE…
[10] Hybrid speciation (pp 279-283)
[11] The molecular choreography of a store-operated calcium channel (pp 284-287)
[12] 14-3-3sigma controls mitotic translation to facilitate cytokinesis (pp 329-332; N&V)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 14 March at 1800 London time / 1400 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 15 March, but at a later date.***
[13] Backtracking determines the force sensitivity of RNAP II in a factor-dependent manner
DOI: 10.1038/nature05701
[14] Epithelial NEMO links innate immunity to chronic intestinal inflammation
DOI: 10.1038/nature05698
[15] Unproductive splicing of SR genes associated with highly conserved and ultraconserved DNA elements
DOI: 10.1038/nature05676
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
Melbourne: 5
CANADA
Montreal: 12
Ottawa: 9
Vancouver: 9
CHINA
Nanjing: 3
FRANCE
Paris: 6
Strasbourg: 2
Toulouse: 2
GERMANY
Bielefeld: 7
Cologne: 14
Dresden: 13
Kaiserslautern: 7
Kiel: 7
Leipzig: 15
Mainz: 6, 14
Wurzburg: 7
ITALY
Milan: 14
Monterotondo: 14
JAPAN
Tokyo: 8
POLAND
Krakow: 2
SPAIN
Madrid: 7
SWITZERLAND
Zurich: 9
UNITED KINGDOM
London: 10
UNITED STATES OF AMERICA
California
Berkeley: 13, 15
Davis: 9
Los Angeles: 1
Pasadena: 4
Stanford: 8, 11
Maryland
Frederick: 13
Massachusetts
Cambridge: 9, 12
Michigan
Ann Arbor: 14
Pennsylvania
Pittsburgh: 3
PRESS CONTACTS…
For North America and Canada
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected]
For Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
For the UK/Europe/other countries not listed above
Helen Jamison, Nature London
Tel: +44 20 7843 4658; E-mail [email protected]
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