WWW.NATURE.COM/NATURE
VOL.437 NO.7061 DATED 13 OCTOBER 2005
This press release contains:
* Astronomy: Deep Impact reveals comet's 'icy dirtball' composition
* Materials: Insects' super-rubber prepared in the lab
* Neurobiology: Potential insights into cocaine's effect on memory
* Nanotechnology: When noise improves hearing
* Microbiology: Antimicrobial peptides isolated in fungi
* Cancer: Abnormal chromosome numbers produce tumours
* Earth Science: Short-term earthquake prediction still elusive
* Palaeontology: South American dinosaur updates family tree
* Virology: Viruses energize host cells
* And finally... Oldest recorded noodles come from China
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[1] Astronomy: Deep Impact reveals comet's 'icy dirtball' composition (pp
987-990; N&V)
When a probe released by the Deep Impact spaceship crashed into comet Tempel
1 on 4 July this year it vaporized 4,500 tonnes of water, but surprisingly
released even more dust, scientists report in this week's Nature.
Michael Küppers and colleagues watched the collision with the OSIRIS camera
system on ESA's Rosetta spacecraft, itself en route for a comet encounter of
its own in 2014. They say that comets should now be described as 'icy
dirtballs', rather than 'dirty snowballs'.
The scientists also found that the comet's activity had returned to normal
levels a few days after the impact, suggesting that meteorite strikes are
not a cause of cometary outbursts.
CONTACT
Michael Küppers (Max-Planck Institut für Sonnensystemforschung,
Katlenburg-Lindau, Germany)
Tel: +49 5556 979 463; E-mail: [email protected]
<mailto:[email protected]>
Paul D. Feldman (Johns Hopkins University, Baltimore, MD, USA)
Tel: +1 410 516 7339; E-mail: [email protected] <mailto:[email protected]>
[2] Materials: Insects' super-rubber prepared in the lab (pp 999-1002)
A polymer based on an elastic protein called resilin that enables fleas to
jump and cicadas to chirp has been made in the laboratory. The polymer,
desribed in this week's Nature, is extremely rubbery and resilient.
Resilin is found in many insects. Christopher Elvin and colleagues made the
new material by transferring from fruitflies the gene believed to be
responsible for generating the elastic part of resilin, and incorporating it
into Escherichia coli bacteria. A brew of the bugs made a large quantity of
this elastic peptide, which was extracted and treated with light to make the
final rubbery product.
A strip of the synthetic resilin can be stretched to over three times its
original length without breaking. The scientists suggest that the material
could be useful as a replacement for similar materials in the human body,
such as the elastin in arteries.
CONTACT
Christopher M. Elvin (CSIRO Livestock Industries, St Lucia, Australia)
Tel: +61 7321 42506; E-mail: [email protected]
<mailto:[email protected]>
[3] Neurobiology: Potential insights into cocaine's effect on memory
(pp1027-1031)
Drug abuse, such as taking cocaine, can lead to a change in the plasticity
of dopamine neurons in the ventral tegmental area (VTA) of the brain. A
study appearing in Nature this week now suggests that, over time, repeated
exposure to cocaine may influence the formation of drug-associated memory in
the rat VTA. The drug apparently facilitates the long-term potentiation of
connections formed by these dopamine neurons, a process thought to promote
memory formation.
Mu-ming Poo and colleagues treated the rodents with repeated doses
of cocaine and found that neuronal connections from the midbrain tissues of
these animals could easily undergo long-term potentiation in vitro. They
also discovered that the anxiolytic drug diazepam which enhances inhibition
of such cells through the neurotransmitter GABA (gamma-aminobutyric acid),
blocked long-term potentiation. The study suggests that cocaine acts by
reducing GABA's inhibitory effect on neurons. It could also help to explain
the action of the antiepileptic drug gamma-vinyl-GABA (vigabatrin), now in
clinical trials for the treatment of cocaine addiction.
CONTACT
Mu-ming Poo (University of California, Berkeley, CA, USA)
Tel: +1 510 642 2514; E-mail: [email protected] <mailto:[email protected]>
[4] Nanotechnology: When noise improves hearing (pp 995-998)
The idea that if you want to get your message across you should surround it
with more noise sounds a little crazy. But sometimes that's the best thing
to do, as Robert Badzey and Pritiraj Mohanty show in this week's Nature.
They find that a tiny vibrating sliver of silicon about a hundred times
thinner than a human hair, cooled to within a degree or so of absolute zero,
can be switched more reliably between two stable oscillating states - rather
like resonances of a tuning fork - when some noise is mixed into the
switching signal.
This principle by which noise improves the transmission of an
information-laden signal is called stochastic resonance, and it is now a
well-known effect in physics and biology. Animals such as crickets and
crayfish that have to pick up signals (acoustic or electrical, respectively)
in a noisy environment have evolved so that their detection systems take
advantage of stochastic resonance. Too much noise will inevitably overwhelm
a signal, but when stochastic resonance operates, a little noise is better
than none at all.
The miniature beams of silicon studied by Badzey and Mohanty, called
nanomechanical oscillators (because they are just a few hundred nanometres
thick), could conceivably be used for storing and processing information
mechanically. Their two stable states of oscillation are like the two states
of binary digital information in electronic computing and memory devices. A
bank of nanomechanical oscillators could therefore hold and manipulate
binary data. Using stochastic resonance in this way might improve the
reliability of such information processing.
CONTACT
Pritiraj Mohanty (Boston University, Boston, MA, USA)
Tel: +1 617 353 9297; E-mail: [email protected]
<mailto:[email protected]>
[5] Microbiology: Antimicrobial peptides isolated in fungi (pp 975-980)
Research has revealed a special class of antibiotics in fungi that could
prove to be a powerful weapon against drug-resistant infections. Previously
scientists had only isolated these small, antimicrobial peptides called
'defensins' in vertebrates, higher plants and invertebrates. But Hans-Henrik
Kristensen and his colleagues have now shown that these exist in the fungus
Pseudoplectania nigrella as well.
The authors also show that the recombinant form of this defensin,
which they call plectasin, was especially active against Streptococcus
pneumoniae, the microbe that causes pneumonia and meningitis. Plectasin
could potentially be produced at commercially viable levels using
recombinant fungal production systems. The new findings also suggest that
the defensins of insects, molluscs and fungi arose from a common ancestral
gene.
CONTACT
Hans-Henrik Kristensen (Novozymes A/S, Bagsvaerd, Denmark)
Tel: +45 44 42 18 23; E-mail: [email protected] <mailto:[email protected]>
[6] & [7] Cancer: Abnormal chromosome numbers produce tumours (pp 1043-1047&
1038-1042)
The idea that a failure of proper cell division produces genomic instability
and promotes the development of cancer was first proposed by German
biologist Theodor Boveri in 1915. The fact that tumour cells often have
abnormal numbers of chromosomes supports this theory, and two papers
appearing this week in Nature provide new, more direct evidence to support
this.
David Pellman and colleagues tested the theory by blocking cell
division in cells that also lack the tumour suppressor gene p53, to generate
tetraploid cells - cells that contain a double quota of chromosomes.
Compared to their diploid counterparts, which have a normal set of
chromosomes, tetraploid cells were more prone to generate tumours in mice,
and these tumours showed genomic instability similar to many human cancers.
Another study by Qinghua Shi and Randall King shows how tetraploid
cells can arise. The authors show that inaccurate segregation even of a
single pair of chromosomes - an error that does occur every so often - will
halt cell division and produce tetraploid cells.
Together, these papers lend experimental support to Boveri's ideas
that errors in cell division contribute to the development of cancer.
CONTACT
David Pellman (Children's Hospital, Harvard Medical School, Boston, MA, USA)
Tel: 1 617 632 4918; E-mail: [email protected]
<mailto:[email protected]>
Randall W. King (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 432 3629; E-mail: [email protected]
<mailto:[email protected]>
[8] Earth Science: Short-term earthquake prediction still elusive (pp
969-974)
The 2004 Parkfield earthquake in California was the most closely monitored
in history, but the dense network of instruments installed in and around the
fault region picked up no warning signs.
Writing in this week's Nature, William H. Bakun and colleagues conclude that
reliable short-term earthquake prediction is still not achievable.
The 40-kilometre-long Parkfield section of the San Andreas fault has seen at
least six major earthquakes since 1857. In the mid-1980s, seismologists used
this pattern to forecast that another quake would happen by 1993 and
accordingly packed the area with sensors. Although the event actually
arrived 11 years later, which cast doubt on the 'characteristic earthquake'
model, Bakun et al. point out that the experiment's goal of observing a
large earthquake very near to the rupture has been achieved, revealing
important details of earthquake physics.
CONTACT
William. H. Bakun (US Geological Survey, Menlo Park, CA, USA)
Tel: +1 650 329 4793; E-mail: [email protected] <mailto:[email protected]>
[10] Palaeontology: South American dinosaur updates family tree (pp
1007-1011)
Fossil-hunters in Argentina have discovered the earliest and most complete
example of a dromaeosaurid - a small dinosaur related to today's birds -
ever dug up in South America. The new species, which is dated between 97
million and 88.5 million years ago, may require the reshuffling of a portion
of the dinosaur family tree.
The almost-complete skeleton, found at La Buitrera in Neuquén province,
dates from before the break-up of the supercontinent Gondwana. It is
unveiled by Peter Makovicky, Sebastián Apesteguía and Federico Agnolín in
this week's Nature.
The discovery suggests that other contemporary dinosaurs, such as
Rahonavis, may have been more closely related to the new dinosaur than to
birds, suggesting that these creatures represented their own distinct
lineage within the dromaeosaurid group.
CONTACT
Peter J. Makovicky (The Field Museum, Chicago, IL, USA)
Tel: +1 312 665 7633; E-mail: [email protected]
<mailto:[email protected]>
[11] Virology: Viruses energize host cells (AOP)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 12
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 13 October, but at a later date.***
DOI: 10.1038/nature04111
Viruses, such as influenza, force the cells they infect to make new virus
particles from viral genes injected into the host cell. Reporting in this
week's Nature, Sallie W. Chisholm and colleagues have found that certain
viruses - called phages - that infect bacteria inject viral genes to make
their bacterial host produce energy by photosynthesis. This gives the host
cell an additional energy source so it can produce more virus particles
before it dies, the researchers suggest.
They looked at phages that infect a marine cyanobacterium called
Prochlorococcus. Prochlorococcus is already capable of carrying out
photosynthesis independently. However, the phage injects an additional gene
that codes for a photosynthesis protein called D1, which enables the host to
continue the photosynthetic process even while it is dying from phage
infection.
The photosynthesis genes injected into the host cell didn't originally
belong to the phages themselves. They first got them from their
cyanobacterial host during a previous infection, and then kept them because
of the reproductive advantage these genes bestowed on the virus, the authors
speculate.
CONTACT
Sallie W. Chisholm (Massachusetts Institute of Technology, Cambridge, MA,
USA)
Tel: +1 617 253 1771; E-mail: [email protected] <mailto:[email protected]>
[12] And finally... Oldest recorded noodles come from China (p 967-968)
So you thought that noodles originated in Italy? Not true, say Houyuan Lu
and colleagues. In a Brief Communication in this week's Nature, they
describe the discovery in China of a bowl of beautifully preserved, thin
yellow noodles that are half a metre long and about 4,000 years old.
The researchers discovered the noodles inside an overturned sealed bowl
under 3 metres of floodplain sediment in Lajia, an archaeological site by
the Yellow River in northwestern China. The site harbours a settlement that
was probably destroyed 4,000 years ago by a major earthquake and flood.
To identify the plants the noodles were made from, the team looked at the
shape and patterning of starch grains and so-called seed-husk 'phytoliths'
in the bowl containing the noodles, and compared them with modern crops.
They concluded that the noodles had been prepared using grains from millet
grass. This is different from modern noodles, which are made with wheat
flour. But apart from that, the ancient noodles were produced in just the
same way as noodles today: the grains were ground into flour that was used
to make dough, which was then pulled and stretched into shape before
boiling.
CONTACT
William I. Milne (University of Cambridge, Cambridge, UK)
Tel: +44 1223 332757; E-mail: [email protected] <mailto:[email protected]>
ALSO IN THIS ISSUE...
[13] The N-end rule pathway as a nitric oxide sensor controlling the
levels of multiple regulators(pp 981-986)
[14] Geology and insolation-driven climatic history of Amazonian north
polar materials on Mars (pp 991-994)
[15] Climatic controls on central African hydrology during the past
20,000 years (pp 1003-1006)
[16] SERRATE coordinates shoot meristem function and leaf axial
patterning in Arabidopsis (pp 1022-1026)
[17] Solution structure of a protein denatured state and folding
intermediate (pp 1053-1056)
[18] Carbon nanotubes as cold cathodes (p 18)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 12
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 them on this release to avoid multiple mailings they will not
appear in print on 13 October, but at a later date.***
[19] Histone H3 serine 10 phosphorylation by Aurora B causes HP1
dissociation from heterochromatin
DOI: 10.1038/nature04254
[20] Regulation of HP1-chromatin binding by histone H3 methylation and
phosphorylation
DOI: 10.1038/nature04219
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.
ARGENTINA
Buenos Aires: 10
AUSTRALIA
Armidale: 1
Canberra: 3
Geelong: 3
St. Lucia: 3
Wollongon: 1
CHINA
Beijing: 12
Hefei: 8
Sining: 12
DENMARK
Bagsvaerd: 6
Copenhagen: 6
FRANCE
Marseille: 2
Palaiseau: 18
Velizy-Villacoublay: 18
GERMANY
Berlin: 2
Bremen: 15
Katlenburg-Lindau: 2
INDONESIA
Jakarta: 1
ITALY
Padua: 2
THE NETHERLANDS
De Bilt: 9
Noordwijk: 2
Texel: 15
SPAIN
Granada: 2
SWEDEN
Uppsala: 2
SWITZERLAND
Bern: 2
UNITED KINGDOM
Cambridge: 17
Oxford: 16
UNITED STATES OF AMERICA
Arizona
Flagstaff: 14
California
Berkeley: 3, 9
Davis: 6
Irvine: 13
Los Angeles: 6
Menlo Park: 9
Pasadena: 9, 13
Sacramento: 9
District of Columbia
Washington: 6
Illinois
Chicago: 10
Louisiana
Baton Rouge: 12
Massachusetts
Boston: 5, 7, 8
North Grafton: 7
Woods Hole: 15
New York
Palisades: 9
Washington
Vancouver: 9
PRESS CONTACTS...
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For Japan, Korea, China, Singapore and Taiwan
Rinoko Asami, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
<mailto:[email protected]>
For the UK/Europe/other countries not listed above
Ruth Francis, Nature London
Tel: +44 20 7843 4562; E-mail [email protected]
<mailto:[email protected]>
Katharine Mansell, Nature London
Tel: +44 20 7843 4658; E-mail: [email protected]
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