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This press release is copyright Nature.
VOL.438 NO.7065 DATED 10 NOVEMBER 2005
This press release contains:
* Summaries of newsworthy papers:
* Gene expression: Use it, or lose it
* Seismology: Earthquake initiation predicts its ultimate strength
* Neuroscience: Sex on the brain
* Neuroscience: Resetting the clock in flies
* Neurobiology: The pathway of disgust in worms
* Phylogeny: Pacific birds rewrite evolutionary textbook
* Physics: Wafer-thin graphite is a quantum conundrum
* Green chemistry: Efficient catalyst for making 'biodiesel'
* And finally... Gravity tractor could move dangerous asteroids
* Mention of papers to be published at the same time with the same embargo
* Geographical listing of authors
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[1] Gene expression: Use it, or lose it (pp220-223)
Two primary mechanisms driving evolution are believed to be mutation and
selection. But what is the degree of mutation alone when there is no or
little selection? It's surprisingly big in fruitflies, say Kevin White and
colleagues in a paper in Nature this week. They found that flies mated in
the laboratory, under conditions of low selection pressure, become more
different than expected in comparison with the differences in wild
fruitflies belonging to different species that are, effectively, millions of
generations apart.
The authors report that they kept 12 separate lines of fruitflies that were
initially identical. After 200 generations, they found that about a third of
their genes showed significant variation in their expression levels. This
variation is much higher than what is observed in the wild after a similar
number of generations. The researchers speculate that in wild flies,
selection probably eliminates many of the mutations that cause such
variations in gene expression.
The experiments also showed that gene expression between the 12 fruitfly
lines differed less after 200 generations for genes that encode important
developmental cellular proteins. The researchers speculate that selection
weeds out mutations in such genes.
CONTACT
Kevin P White (Yale University, New Haven, CT USA)
Tel: + 1 203 785 5572; E-mail: [email protected]
[2] Seismology: Earthquake initiation predicts its ultimate strength
(pp212-215; N&V)
The first few seconds of an earthquake may hold the key to its ultimate
magnitude, an analysis in this week's Nature shows.
Erik Olson and Richard Allen studied records of 71 large earthquakes from
the past few decades. They find that the frequency content of radiated
seismic energy within the first few seconds of rupture scales with the final
magnitude of the event.
The discovery goes against the widely accepted idea that the magnitude of an
earthquake cannot be determined before the rupture is complete. The new
analysis instead suggests that an earthquake's ultimate strength can be
predicted to some degree from its initial characteristics, raising the hope
that we may one day understand how faults rupture in enough detail to
predict the severity of an earthquake when it is initiated. A related News &
Views article by Rachel Abercrombie accompanies this research.
CONTACT
Richard M Allen (University of California Berkeley, Berkeley, CA, USA)
Tel: + 1 510 642 1275, E-mail: [email protected]
Rachel Abercrombie (Boston University, MA, USA)
Tel: +1 617 358 2571; E-mail: [email protected]
[3] Neuroscience: Sex on the brain (pp229-233)
A cluster of neurons in the fruitfly brain has been found to differ between
male and females, according to research in this week's Nature. Kimura and
colleagues show that this difference is produced by active elimination of
neuronal precursor cells in females.
The fruitless gene in the fruitfly Drosophila was first identified
because males with fruitless mutations show homosexual courtship behaviours.
The gene products of fruitless differ between males and females, but no
obvious neuroanatomical differences between male and female fruitfly brains
had previously been found.
Kimura and colleagues now show that the male-specific Fruitless
protein inhibits programmed cell death in a cluster of neurons, allowing
them to form a neural circuit that directs male fruitflies to court females
and not males. This research shows how a single gene can direct brain
development and subsequently a sex-specific behaviour. In this framework,
sexual orientation can be understood in relation to an identified neuronal
circuit and defined actions of a sex-determination gene. The cover image
shows neurons in this key brain region.
CONTACT
Ken-Ichi Kimura (Hokkaido University of Education, Hokkaido, Japan)
Tel: + 81 126 32 0341; E-mail: [email protected]
[4] Neuroscience: Resetting the clock in flies (pp238-242; N&V)
Scientists have found evidence for a resetting signal that enables
Drosophila fruitflies to keep their daily rhythm up to speed. In a paper
appearing in this week's issue of Nature, Michael Rosbash and his colleagues
have genetically engineered fruitflies to have altered circadian periods in
the two groups of clock neurons that regulate morning and evening activity.
The research team found that the 'morning' cells determine the
period of the entire system by providing a daily reset signal to the evening
cells. The findings indicate that the coherence of the circadian network in
flies is maintained by intercellular communication signals. In the future,
biologists hope to find out if similar circuits also operate to maintain
mammalian circadian rhythms. A related News & Views article by Michael N.
Nitabach accompanies this research.
CONTACT
Michael Rosbash (Brandeis University, Waltham, MA, USA)
Tel: +1 781 736 3160; E-mail: [email protected]
Michael N. Nitabach (Yale School of Medicine, New Haven, CT, USA)
Tel: +1 203 737 2939; E-mail: [email protected]
[5] Neurobiology: The pathway of disgust in worms (pp179-184)
Just as in humans, pathogenic bacteria can invade the intestines of
Caenorhabditis elegans nematode worms and cause them to fall sick. But a new
study appearing in Nature this week shows that these nematode worms can
remember the smell of the offending soil bacteria and avoid the scent in the
future.
Cornelia Bargmann and her colleagues found that the odour of the
pathogenic bacteria upregulates the neurotransmitter serotonin after
infection. This is particularly interesting because serotonin signalling in
the gut is associated with the nausea brought about by chemotherapy in
people. In fact, serotonin signalling is a major target of anti-nausea
drugs. From an evolutionary perspective, the results suggest that the role
of serotonin in signalling intestinal malaise evolved early on and is
conserved in many animals.
CONTACT
Cornelia L Bargmann (Rockefeller University/Howard Hughes Medical Institute,
New York, NY, USA)
Tel: +1 212 327 7242; E-mail: [email protected]
[6] Phylogeny: Pacific birds rewrite evolutionary textbook (pp216-219)
Evolutionary biologists have long assumed that species in island-rich areas
such as the Pacific Rim diverge and evolve in a series of 'stepping-stone'
dispersals from one island to the next. But a new analysis of the family
tree of tropical Pacific birds suggests that this cherished assumption is
not true.
Christopher Filardi and Robert Moyle analysed DNA from a host of bird
species from the family Monarchidae, commonly called Monarch flycatchers. As
they report in this week's Nature, the species seem to have colonized the
area not in a series of separate stepping-stone excursions from continental
land masses, but in a single, even spread across all Pacific archipelagos.
The researchers support their conclusion by pointing out that, of the six
different species groups that are confined to a single island chain, all are
embedded within a group, or genus, called Monarcha. This genus is spread
across the entire tropical Pacific, showing that all of these remote species
arose from a single lineage. What's more, the authors point out, some
species show evidence of having recolonized continental areas such as
Australia - contrary to the previous idea that that species colonize island
chains only by moving away from continents.
CONTACT
Christopher E Filardi (American Museum of Natural History, New York, NY,
USA)
Tel: +1 212 313 7431; E-mail: [email protected]
[7] & [8] Physics: Wafer-thin graphite is a quantum conundrum (pp197-200 &
201-204; N&V)
Exotic electronic behaviour in sheets of graphite just one atom thick,
reported by two groups in this week's Nature, reveals quantum-mechanical
effects never seen before, and could find applications in microelectronics.
The two groups, one led by Andre Geim and the other by Philip Kim, both
study the way that electrons moving through electrically conducting
materials behave differently when they are confined to a two-dimensional
'flatland' in very thin slabs or films.
Such behaviour have been known for many years in thin metal films. But
graphite is different, as the two teams discover. They have used microscopic
and micromanipulation techniques to separate out the individual sheets of
carbon atoms that are layered on top of one another in normal graphite.
These layers are electrically conducting because they contain electrons that
are free to roam across a layer. But a single graphite layer, called
graphene, proves to be unlike a two-dimensional metal in its electronic
behaviour.
For example, the conductivity of a graphene sheet never falls below a
minimum value, even when there should be no mobile electrons at all in the
sheet. Geim and colleagues point out that graphene behaves as if the
electrical current, rather than being carried by normal electrons, is being
borne by charged particles with no mass at all when they are at rest, like
photons of light. All of this makes graphene a rich system for exploring
unusual quantum-mechanical electronic behaviour. A related News & Views
article by Charles L. Kane accompanies this research.
CONTACT
Andre K Geim (University of Manchester, Manchester, UK) paper no: [7]
Tel: + 44 161 275 4120; E-mail: [email protected]
Philip Kim (Columbia University, New York, NY, USA) paper no: [8]
Tel: +1 212 854 0102; E-mail: [email protected]
Charles L. Kane (University of Pennsylvania, Philadelphia, PA, USA)
Tel: +1 215 898 8149; E-mail: [email protected]
[9] Green chemistry: Efficient catalyst for making 'biodiesel' (p178)
A solid acid catalyst that can convert vegetable oils into 'biodiesel' fuel
could replace the expensive and inefficient process used today, according to
a Brief Communication in this week's Nature.
Fatty acids, such as oleic acid and stearic acid, must be converted into
chemicals called esters before they can be used to fuel vehicles. Sulphuric
acid is commonly used as a catalyst to make this process happen, but
separating the products from the liquid acid is costly and chemically
wasteful. More expensive solid acids have been tried, but they tend to be
difficult to recycle.
Michikazu Hara and colleagues have now shown that a charred mixture of
sugars, starch or cellulose can be treated with sulphuric acid to create a
solid acid that is completely insoluble, very cheap to prepare, and easy to
recycle. It is more than half as catalytically active as liquid sulphuric
acid, and a great improvement over other solid acid catalysts tried
previously.
CONTACT
Michikazu Hara (Tokyo Institute of Technology, Yokohama, Japan)
Tel: +81 45 924 5239, E-mail: [email protected]
[10] And finally... Gravity tractor could move dangerous asteroids
(pp177-178)
The next time an asteroid threatens to crash into the Earth, forget about
calling Bruce Willis - send for the gravity tractor instead. Designs for the
innovative space tug are unveiled in a Brief Communication to this week's
Nature.
Because a large asteroid could cause widespread damage if it hit the Earth,
scientists are looking for ways to nudge these chunks of rock away from a
potential collision course.
Stanley G. Love and Edward T. Lu, both NASA astronauts point out that
attaching a spacecraft to the surface of an asteroid and pushing on it
directly could be tricky, as these objects tend to be little more than
collections of rubble.
They argue that a spacecraft could simply hover over the surface and use its
gravitational interaction as a towline instead. The tractor's thrusters
would be angled outwards so that they do not blast the asteroid's surface
and reduce the towing force. The authors calculate that, with sufficient
warning, a 20-tonne gravity tractor could safely deflect an asteroid 200
metres across in about a year of such 'towing'.
CONTACT
Edward T. Lu (NASA, Johnson Space Center, Houston, TX, USA)
Tel: +1 281 244 8901, E-mail: [email protected]
Stanley G. Love (NASA, Johnson Space Center, Houston, TX, USA)
Tel: +1 281 244 2618, E-mail: [email protected]
ALSO IN THIS ISSUE...
[11] Subunit arrangement and function in NMDA receptors (pp185-192)
[12] Simulation of equatorial and high-latitude jets on Jupiter in a deep
convection model (pp193-196)
[13] A record of Permian subaqueous vent activity in southeastern Brazil
(pp205-207)
[14] Possible solar origin of the 1,470-year glacial climate cycle
demonstrated in a coupled model (pp208-211)
[15] Suppression of Polycomb group proteins by JNK signalling induces
transdetermination in Drosophila imaginal discs (pp234-237)
[16] Cis-trans isomerization at a proline opens the pore of a
neurotransmitter-gated ion channel (pp248-252; N&V)
[17] Principal pathway coupling agonist binding to channel gating in
nicotinic receptors (pp243-247)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 9
November 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 10 November, but at a later date.***
[18] Functional waters in intraprotein proton transfer monitored by FTIR
difference spectroscopy
DOI: 10.1038/nature04231
[19] Wnt-Ry signalling mediates medial-lateral retinotectal topographic
mapping
DOI: 10.1038/nature04334
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.
BRAZIL
Curitiba: 13
Rio de Janeiro: 13
Sao Paulo: 13
CANADA
Edmonton: 12
GERMANY
Katlenburg-Lindau: 12
Potsdam: 14
Bochum: 18
Bremerhaven: 14
Heidelberg: 14, 15
JAPAN
Iwamizawa: 3
Sendai: 3
Tokyo: 3, 9
Tsukuba: 9
Yokohama: 9
THE NETHERLANDS
Nijmegen: 7
RUSSIA
Chernogolovka: 7
UNITED KINGDOM
Cambridge: 16
London: 15
Manchester: 7
UNITED STATES OF AMERICA
California
Berkeley: 2
Los Angeles: 12
Pasadena: 16
Connecticut
New Haven: 1
Florida
Tallahassee: 1
Illinois
Chicago: 19
Massachusetts
Cambridge: 1
Minnesota
Rochester: 17
New York
New York: 5, 6, 8, 11
Oregon
Portland: 11
Pennsylvania
Philadelphia: 1
Texas
Houston: 10
Wisconsin
Madison: 2
PRESS CONTACTS...
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Tel: +1 202 737 2355; E-mail: [email protected]
<mailto:[email protected]>
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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