Nature (Vol. 436, No. 7051, 4 August 2005)

147 Pages·2005·12.169 MB·English

Volume 436 Number 7051 pp603-752
In this issue (4 August 2005) • News and Views
• Editorials • Brief Communications
• Research Highlights • Feature
• News • Review Article
• News Features • Articles
• Business • Letters
• Correspondence • Naturejobs
• Books and Arts • Futures

Editorials
Station at a crossroads p603
Frank international discussions need to start immediately if anything is to be salvaged from the space
station, whose completion currently relies on the ailing space shuttle.

Count themselves lucky p603
Mathematicians might think they have an image problem, but the public holds them in great esteem.

A dog's life p604
The first cloned dog was born at some cost, and there needn't be many more.

Research Highlights
Research highlights p606

News
Senator boosts chances of stem-cell reform p608
Majority leader changes mind over funding rules.
Erika Check

More falling foam puts shuttle programme in serious doubt p608
Fleet grounded as NASA seeks solutions.
Mark Peplow

Bone cells linked to creation of fresh eggs in mammals p609
Hackles rise over claims on ovulation.
Claire Ainsworth

Sidelines p610

Shadow hangs over research into Japan's bomb victims p610
Radiation foundation faces uncertain future.
Tom Simonite

Mars orbiter ready to scout for future landing sites as NASA looks ahead p613
Launch date approaches for next mission to red planet.
Tony Reichhardt

Drugs could head off a flu pandemic — but only if we respond fast enough p614
Models show how spread of disease might be stopped.
Declan Butler

US energy bill pushes research but fails to cut consumption p615
Critics slam policy as compromise rather than strategy.
Emma Marris

News in brief p616

News Features
Pluto voyage: A man with a mission p618
In 2015, Pluto will welcome its first visitor, a robot named New Horizons. Amanda Haag meets the planetary
scientist who nursed the mission through its darkest days.

Malyasian biotechnology: The valley of ghosts p620
While other Asian tigers are roaring ahead in biotechnology, Malaysia's BioValley is going nowhere fast.
David Cyranoski asks what went wrong.

I
Dramatizing maths: What's the plot? p622
Can mathematicians learn from the narrative approaches of the writers who popularize and dramatize their
work? Sarah Tomlin is on the story.

Business
Fatal attraction p624
Oxford Instruments has paid dear for its bold efforts to stretch the boundaries of magnet performance,
as Andrea Chipman reports.

In Brief p625

Market Watch p625

Correspondence
China building teams to tackle public-health crises p626
Yu Wang, Guang Zeng and Robert E. Fontaine

Education and penalties are key to tackling misconduct p626
Kai Wang

Academia's 'misconduct' is acceptable to industry p626
Ian Taylor

Misconduct: pressure to achieve corrodes ideals p626
Lutz P. Breitling

Books and Arts
Cool is not enough p627
There's more to life than the second law of thermodynamics.
J. Doyne Farmer reviews Into the Cool: Energy Flow, Thermodynamics and Life by Eric D. Schneider and Dorion
Sagan

Russia's secret weapons p628
Jens H. Kuhn, Milton Leitenberg and Raymond A. Zilinskas review Biological Espionage: Special Operations
of the Soviet and Russian Foreign Intelligence Services in the West by Alexander Kouzminov

Science in culture: Surface tensions p629
A reinterpretation, using damaged photographs, of a failed attempt to fly to the North Pole.
Colin Martin

News and Views
Geochemistry: On the Moon as it was on Earth p631
Does the Moon's surface contain an archive of the early history of Earth? According to an intriguing idea,
based on recently published analyses of lunar soils, it might do — and the proposal can be tested.
Bernard Marty

Neurobiology: Getting axons going p632
Neurons extend one long axon, through which they transmit electrical impulses to other cells in the nervous
system. Surprisingly, it seems that where the axon forms is determined entirely within the neuron.
Juergen A. Knoblich

Quantum Information: Putting certainty in the bank p633
A new way to manipulate quantum states resolves a long-standing conundrum about who knows what, and when
and how, in the quantum world. The result is, as one has come to expect, startling and counterintuitive.
Patrick Hayden

50 & 100 years ago p634

Ecology: Neutral theory tested by birds p635
A continental-scale analysis of habitat and bird distribution in South America provides the latest
challenge for neutral theory — a controversial idea in ecology about what determines the make-up of
communities.
Annette Ostling

Cancer: Crime and punishment p636
Cellular senescence stops the growth of cells. This process, first glimpsed in cell culture, is now
confirmed by in vivo evidence as a vital mechanism that constrains the malignant progression of many
tumours.
Norman E. Sharpless and Ronald A. DePinho

Earth science: Trouble under Tonga? p637
Earthquakes occur in cool, foundering tectonic plates deep within the Earth. But seismic data from the
southwestern Pacific indicate that the minerals that make up the plates at depth don't behave as if they
are cool.
George Helffrich

II
Cell biology: Without a raft p638
The spatial organization of signalling proteins in the cell membrane is often ascribed to lipid-based
'rafts'. But single-molecule tracking reveals that such organization probably arises by protein−protein
interactions.
Ben Nichols

Brief Communications
Dogs cloned from adult somatic cells p641
Byeong Chun Lee, Min Kyu Kim, Goo Jang, Hyun Ju Oh, Fibrianto Yuda, Hye Jin Kim, M. Hossein Shamim, Jung
Ju Kim, Sung Keun Kang, Gerald Schatten and Woo Suk Hwang

Tumour biology: Senescence in premalignant tumours p642
Manuel Collado, Jesús Gil, Alejo Efeyan, Carmen Guerra, Alberto J. Schuhmacher, Marta Barradas, Alberto
Benguría, Angel Zaballos, Juana M. Flores, Mariano Barbacid, David Beach and Manuel Serrano

Feature
What Henslow taught Darwin p643
How a herbarium helped to lay the foundations of evolutionary thinking.
David Kohn, Gina Murrell, John Parker and Mark Whitehorn

Review Article
A possible unifying principle for mechanosensation p647
Ching Kung

Articles
Terrestrial nitrogen and noble gases in lunar soils p655
M. Ozima, K. Seki, N. Terada, Y. N. Miura, F. A. Podosek and H. Shinagawa

Oncogene-induced senescence as an initial barrier in lymphoma development p660
Melanie Braig, Soyoung Lee, Christoph Loddenkemper, Cornelia Rudolph, Antoine H.F.M. Peters, Brigitte
Schlegelberger, Harald Stein, Bernd Dörken, Thomas Jenuwein and Clemens A. Schmitt

Letters
The obscuration by dust of most of the growth of supermassive black holes p666
Alejo Martínez-Sansigre, Steve Rawlings, Mark Lacy, Dario Fadda, Francine R. Marleau, Chris Simpson, Chris
J. Willott and Matt J. Jarvis

No oceans on Titan from the absence of a near-infrared specular reflection p670
R. A. West, M. E. Brown, S. V. Salinas, A. H. Bouchez and H. G. Roe

Partial quantum information p673
Micha Horodecki, Jonathan Oppenheim and Andreas Winter

Measurement of the conductance of single conjugated molecules p677
Tali Dadosh, Yoav Gordin, Roman Krahne, Ilya Khivrich, Diana Mahalu, Veronica Frydman, Joseph Sperling,
Amir Yacoby and Israel Bar-Joseph

Stability of the Larsen B ice shelf on the Antarctic Peninsula during the Holocene epoch
p681
Eugene Domack, Diana Duran, Amy Leventer, Scott Ishman, Sarah Doane, Scott McCallum, David Amblas, Jim
Ring, Robert Gilbert and Michael Prentice

Increasing destructiveness of tropical cyclones over the past 30 years p686
Kerry Emanuel

Earthquake slip weakening and asperities explained by thermal pressurization p689
Christopher A. J. Wibberley and Toshihiko Shimamoto

Dental microwear texture analysis shows within-species diet variability in fossil hominins
p693
Robert S. Scott, Peter S. Ungar, Torbjorn S. Bergstrom, Christopher A. Brown, Frederick E. Grine, Mark
F. Teaford and Alan Walker

Refractory periods and climate forcing in cholera dynamics p696
Katia Koelle, Xavier Rodó, Mercedes Pascual, Md. Yunus and Golam Mostafa

Genetic interactions between polymorphisms that affect gene expression in yeast p701
Rachel B. Brem, John D. Storey, Jacqueline Whittle and Leonid Kruglyak

Centrosome localization determines neuronal polarity p704
Froylan Calderon de Anda, Giulia Pollarolo, Jorge Santos Da Silva, Paola G. Camoletto, Fabian Feiguin
and Carlos G. Dotti

Licensing of natural killer cells by host major histocompatibility complex class I molecules
p709
Sungjin Kim, Jennifer Poursine-Laurent, Steven M. Truscott, Lonnie Lybarger, Yun-Jeong Song, Liping Yang,
Anthony R. French, John B. Sunwoo, Suzanne Lemieux, Ted H. Hansen and Wayne M. Yokoyama
III
The origin of the naked grains of maize p714
Huai Wang, Tina Nussbaum-Wagler, Bailin Li, Qiong Zhao, Yves Vigouroux, Marianna Faller, Kirsten Bomblies,
Lewis Lukens and John F. Doebley

BRAFE600-associated senescence-like cell cycle arrest of human naevi p720
Chrysiis Michaloglou, Liesbeth C. W. Vredeveld, Maria S. Soengas, Christophe Denoyelle, Thomas Kuilman,
Chantal M. A. M. van der Horst, Donné M. Majoor, Jerry W. Shay, Wolter J. Mooi and Daniel S. Peeper

Crucial role of p53-dependent cellular senescence in suppression of Pten-deficient
tumorigenesis p725
Zhenbang Chen, Lloyd C. Trotman, David Shaffer, Hui-Kuan Lin, Zohar A. Dotan, Masaru Niki, Jason A. Koutcher,
Howard I. Scher, Thomas Ludwig, William Gerald, Carlos Cordon-Cardo and Pier Paolo Pandolfi

A cytokinesis furrow is positioned by two consecutive signals p731
Henrik Bringmann and Anthony A Hyman

Transcription of mammalian messenger RNAs by a nuclear RNA polymerase of
mitochondrial origin p735
Julia E. Kravchenko, Igor B. Rogozin, Eugene V. Koonin and Peter M. Chumakov

TRBP recruits the Dicer complex to Ago2 for microRNA processing and gene silencing p740
Thimmaiah P. Chendrimada, Richard I. Gregory, Easwari Kumaraswamy, Jessica Norman, Neil Cooch, Kazuko
Nishikura and Ramin Shiekhattar

Naturejobs
Prospect
You've got to laugh... p745
Grad students get connected through comics
Paul Smaglik

Careers and Recruitment
An individual approach p746
Reduced side effects and more effective therapies are some of the benefits promised by pharmacogenomics.
But to reach these goals industry will have to marshall a broad range of skills, as Ricki Lewis explains.
Ricki Lewis

Special Report
On firm foundations p748
Flexible and relatively unfettered, non-profit foundations are able to boldly go into areas of research
funding often untouched by public bodies, says Helen Gavaghan.
Helen Gavaghan

Futures
Pigs on the wing p752
Aurorae in the sky with diamonds, just $10.99 (exc. tax).
K. Erik Ziemelis
IV
4.8 Editorials 603 MH 2/8/05 2:27 PM Page 603
www.nature.com/nature Vol 436 |Issue no. 7051|4 August 2005
Station at a crossroads
Frank international discussions need to start immediately if anything is to be salvaged from the space
station, whose completion currently relies on the ailing space shuttle.
U
ntil about a week ago, most observers of the space shuttle They have already stood by helplessly for years, watching NASA
assumed that the fleet could be kept alive until its planned make essentially unilateral decisions to scale back the design accord-
retirement in 2010. ing to the vagaries of US budget politics. Why should they continue
But the latest mission of the shuttle Discovery, with its daily litany to put up with this?
of stuck fuel gauges, falling foam and chipped tiles (see page 608), Well, for one thing, they may not have much choice. But it also
raises the prospect that this cannot happen. The ageing shuttle’s runs counter to the interests of the Japanese and European space
problems may soon become so difficult to analyse and so expensive agencies to watch NASA — which leads most international space
to fix that even its staunchest defenders will see that the time has projects and will continue to do so for the foreseeable future —
come to stop throwing good money after bad. damage its reputation in further, forlorn efforts to keep the ailing
What then? The International Space Station is at least 15 shuttle shuttle in space.
flights away from completion, and that’s just counting its largest ele- The international partners could also make use of the delay to
ments, the European and Japanese laboratory modules and the negotiate better terms for their participation in the space-station pro-
trusses for solar-power arrays. Several more flights are needed to ject. Michael Griffin, the latest
“It runs counter to the
haul up the experimental racks that would equip the laboratories. NASA administrator, has made
interests of Japan and
The Russian Soyuz crew vehicle and Progress supply ship are each no secret of his low regard for
far too small to carry these large components into orbit. Europe’s the station since his appoint- Europe to watch NASA
Automated Transfer Vehicle (ATV), a new cargo carrier scheduled ment in April. Except for med- damage its reputation in
to debut on an Ariane rocket next year, can deliver tons of supplies ical research on astronauts further forlorn efforts to
but not large sections of the station. Japan’s proposed cargo carrier, and technology tests related to
keep the shuttle in space.”
called the HTV, can handle the experiment racks, but won’t enter the Moon–Mars programme,
service until 2010. So abandoning the shuttle now would leave the NASA’s use of it is likely to be scaled back, so it ought to cede more
station in its current, half-finished state. laboratory time, more astronaut participation and more mission-
One alternative to that would be for NASA to start work as quickly control involvement to Europe and Japan.
as possible on a shuttle-derived vehicle (SDV) that would replace the Such an arrangement would assume that NASA’s long-suffering
component of the shuttle that carries astronauts with a giant cargo international partners would relish an enhanced role in the project.
pod. Such an approach is needed anyway for the proposed return Publicly, their commitment to the space station is as robust as ever.
to the Moon. In principle, the SDV could deliver the rest of the But if, in truth, they’d rather leave the project in its current state,
large pieces of the station, which astronauts, ferried to space on abandon their laboratory modules, and start spending their taxpay-
Russian vehicles, could assemble in orbit. In the four or five years ers’ money on something more useful, now is surely the time to say
it would be expected to take to design and build the SDV, Russian so. NASA could then offer something else — probably a prominent
vehicles and Europe’s ATV could keep the station aloft, lightly role in other cooperative projects — to compensate for reneging on
staffed and stocked. its obligation to complete the US end of the deal. Either way, it’s time
Such a plan would require Europe and Japan to accept yet another for some plain speaking and creative thinking, not for stubbornly
major delay to the date on which their labs will enter operation. sticking to an obsolete plan. ■
Count themselves lucky It is probably fair to say that many mathematicians feel themselves
perceived as unable to conduct the simplest practical task, unfash-
ionably attired, nerdy and isolated from the real world.
Mathematicians might think they have an image A collection of the jokes that mathematicians tell each another
problem, but the public holds them in great esteem. (Not. Am. Math. Soc.52,24; 2005) reveals an element of self-mock-
ery of their obsessive and pedantic natures. Who else would laugh
L
ike people in many disciplines, mathematicians are prone to at the suggestion that what you get by crossing an elephant with a
bouts of concern that they have an image problem. Only last banana is |elephant| ∗ |banana| ∗ sin(cid:1)?
month, some of them convened on the Greek island of Additionally, as they are never shy to tell the rest of us, mathe-
Mykonos with a group of writers to consider how a better use of maticians receive only a tiny slice of the overall research funding.
narrative could help them with their work — and with their public And although it clearly costs much less to prove a theorem than
relations (see page 622). it does to clone a cow, their small grants are inevitably interpreted
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4.8 Editorials 603 MH 2/8/05 2:27 PM Page 604
EDITORIALS NATURE|Vol 436|4 August 2005
by mathematicians as a sure sign that their work is undervalued. Hardy invited him to Cambridge, but Ramanujan caught a cold
These negative associations have been reinforced by a number of that developed into a terminal case of tuberculosis. When Hardy
popular stories about great mathematicians. The American inven- visited his ailing protégé one day by taxi, he commented that the
tor of cybernetics theory, Norbert Wiener, for example, is frequently cab’s number, 1729, was “rather dull”. On the contrary, Ramanujan
depicted as the archetypal absent-minded professor. It is said he insisted, it is the smallest number expressible as the sum of two
once lost his way walking home from the Massachusetts Institute different pairs of cubes.
of Technology. He came across a small girl in the street and asked Earlier eras have produced equally poignant anecdotes. One
if she could give him directions. “Yes, daddy,” she replied, “I'll take thinks, for example, of Évariste
“There seems to be an
you home.” Galois, the unruly French
insatiable public appetite
Kurt Gödel, whose incompleteness theorem sent shock waves mathematician who made great
through mathematics in the 1930s, was a noted misanthrope, who stridesin group theory. He fran- for tales of the almost
shunned human contact at the Institute for Advanced Study in tically scribbled down his work supernatural intellectual
Princeton, preferring colleagues to communicate via pieces of paper for posterity on the eve of his powers of mathematics’
stuffed through the crack beneath the door of his office. fatal duel in 1832 at the age of
more famous figures.”
Despite — or, perhaps, because of — such behaviour, the history just 20. Such stories have pro-
of mathematics is probably more colourful than that of any other pelled books such as Simon Singh’s on Fermat’s last theorem to
scientific discipline. And there seems to be an insatiable public bestseller status.
appetite for tales of the almost supernatural intellectual powers of its These tales are popular not just for their panache, but because
more famous figures. they celebrate mathematicians as pure intellectuals who, unlike
Srinivasa Ramanujan, for example, an Indian mathematician of physicists, biologists or chemists, are untainted by applications of
towering ability in number theory who died at the age of only 32, their work. For even though mathematics is eminently useful, its
first came to the attention of the eminent British mathematician application barely features in its public reputation. Disciplines that
G. H. Hardy by sending his notebooks to him while he worked as a are traditionally inclined to disdain pure theory — biology springs
clerk in Madras. Hardy correctly concluded that even if he couldn't to mind — should take note of the success with which mathematics,
follow all of the proofs, only a genius could have thought of the this most theoretical of disciplines, has haplessly bungled its way
theorems they were seeking to address. into people’s hearts. ■
A dog’s life mechanisms and even identifying new therapies. Deriving embry-
onic stem cells would also pave the way to therapeutic cloning in
dogs — perhaps providing a useful animal model for research into
The first cloned dog was born at some cost, and human health.
there needn’t be many more. The initial dog-cloning experiment has proven the process to be
remarkably inefficient, however,
An Afghan hound born in South Korea in June adds dogs to with only two live births — and “It is unlikely that even
the small list of animal species that have been successfully one survivor — from a total of the most obsessive
cloned (see page 641). The birth marks another first for the 1,095 embryos implanted in
pet owner would
Korean-based group that cloned the first human embryos last year. 123 surrogate mothers. This
contemplate preparing
The development has some scientific significance, on account of offers scant prospects for com-
the emerging importance of the dog as a model for the study of cer- mercial pet cloning, the applica- more than 100 failed
tain aspects of human genetics, development, behaviour and disease. tion of the work that the media pregnancies for just one
A dog genome project is being undertaken by a US team, and the is likely to make a fuss about. It successful birth.”
cloning of dogs could provide an additional tool for researchers. The is unlikely that even the most
number of cloned dogs that will be needed for such research is obsessive pet owner would contemplate preparing more than 100
probably small, however. Scientists such as Elaine Ostrander of the failed pregnancies for just one successful birth — especially when
US National Human Genome Research Institute, head of the dog- there is no guarantee that the cloned dog will behave like the one
genome project, do most of their work with pets living at home, not they hope to duplicate. In such circumstances, the cloning of dogs
with kennels of animals bred for research. So the ability to clone for pet owners remains ethically indefensible.
dogs is unlikely to have more than a marginal impact on how such The Korean researchers named their new dog Snuppy, for Seoul
research is done. National University puppy (one can almost imagine the name being
Cohorts of cloned dogs could potentially be used to study the chosen — presumably on a conference call with the university press
respective influence of genes and environment on particular traits, office). Let us wish him a long and happy life and hope that now that
however. And if it were possible to derive embryonic stem-cell lines the concept behind the birth is proven, dogs are cloned only when
from cloned dog embryos — something that’s so far only been strictly required for research purposes, and that effort is concen-
done in mice and humans — then canine diseases could be studied trated on work that carries the most likely rewards for canine and
more easily in Petri dishes, perhaps providing insights into disease human health. ■
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Vol 436|4 August 2005
RESEARCH HIGHLIGHTS
M
A fish cooperative CO
REPL.
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Biol. Lett. doi:10.1098/rsbl.2005.0344 AT
N
(2005) A /
A study of small ‘cleaner’ fish, which WM
groom larger reef fish in return for OU
D
protection, has shown the sacrifice G.
they make to maintain this precarious
cooperation.
The cleaner wrasseLabroides
dimidiatushelps its host by gobbling
parasites, but can also do damage by
tucking into its host’s tastier mucus.
Observations have suggested that reef
fish punish their cleaners for eating
mucus either by chasing them or by
finding a new cleaner.
Redouan Bshary from the University
of Neuchâtel, Switzerland, and
Alexandra Grutter from the University
of Queensland, Australia, show that L.
dimidiatuslearns to avoid punishment
by changing its feeding habits.
CHEMICAL PHYSICS Jean-Jacques Remy of the Developmental VIRAL GENETICS
Born into nobility Biology Institute of Marseille, France, and Catching the flu
Oliver Hobert of the Columbia University
Europhys. Lett. 71,276–282 (2005) Medical Center in New York, also identified PLoS Biol.3,300 (2005)
Palladium has been endowed with noble the protein required for this olfactory Influenza viruses (pictured) are known to
status by Erwin Hüger of the Technical imprinting. Called SRA-11, it belongs to a swap genes. This process, called
University of Clausthal and Krzysztof Osuch class of olfactory receptors, but shows up on reassortment, may produce more virulent
of the University of South Africa. connecting interneurons rather than on strains. To quantify the rate at which
The noble behaviour, or relative lack of sensory neurons. Its precise role is a mystery. reassortment happens, Edward Holmes of
reactivity, of metals such as copper, silver and Pennsylvania State University in College
genoledr gryes luevltesl f irno mth et hme ectoaml cpalleleted ftihllein dgb oafn adn. FEEgRTgIL bIToYxes Parskt uadnide dh itsh ceo glleenaogmueess RCE / SPL
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Lone atoms of palladium have filled dshells, of 156 H3N2 O
but in the bulk metal the band partly empties. Cell 122, 303–315 (2005) influenza A strains CE S
N
Hüger and Osuch deposited a layer of Cells from the blood collected in New CIE
S
palladium on niobium, which pushes the and bone marrow can York state between
atoms further apart, reasoning that this restock female 1999 and 2004. They
might restore electrons to the dband. The mammals’ ovaries found more gene
resulting monolayer was as unreactive as with eggs. This is the swapping than
silver — partly because the dband became controversial claim expected, and showed
more nearly filled, but also because the of Jonathan Tilly of the that a flu epidemic
band’s energy was lowered, which made Massachusetts General during winter
the electrons less available for reactions. Hospital in Boston and his 2003–04 was caused
colleagues. when a dominant strain
DEVELOPMENTAL BIOLOGY Last year Tilly’s group suggested that from the previous year picked
Scent detectors mouse ovaries contain stem cells that produce up a gene for a key surface protein from a
new eggs in adulthood, challenging the dogma less common strain.
Science309,787–790 (2005) that female mammals are born with a fixed
Caenorhabditis elegans, everyone’s favourite number of eggs. Now they have identified cells BIOTECHNOLOGY
model worm, has been shown to have a long- in bone marrow and blood that make proteins Safe delivery
lasting memory for a smell associated with characteristic of germ cells. They have also
food, providing it is exposed to the cue during shown that bone-marrow transplants or blood Nature Biotechnol. doi: 10.1038/nbt1122 (2005)
its first larval stage. Adult worms primed in transfusions result in donor-derived eggs Scientists hope to exploit the recently
their youth to respond to benzaldehyde, appearing in the ovaries of chemically discovered class of molecules called small
which smells a bit like marzipan, reacted to sterilized female mice. However, the team has interfering RNAs, which target and shut
the odour by laying more eggs and by moving not demonstrated fertilization of these eggs or down specific genes, as novel therapies.
quickly towards its source. embryo development. But a stumbling block is that introduced
606
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4.8 Research Highlights NS 29/7/05 4:37 PM Page 607
NATURE|Vol 436|4 August 2005 RESEARCH HIGHLIGHTS
NE / SPL
ZI
A
M
A
C
S.
RNAs are rapidly degraded in the body. OPTICS
Now, researchers led by David Morrissey A clearer view
at Sirna Therapeutics in Boulder, Colorado,
and at Protiva Therapeutics in Burnaby, Appl. Phys. Lett. 87, 034102 (2005)
British Columbia, have found a way to In principle, flat lenses that focus light to a
protect the RNA from destruction using a point of infinite precision can be made
lipid bilayer. using materials with a negative refractive
They enclosed siRNAs directed against the index. Such materials, which can be made
hepatitis B virus within bilayer particles, and from arrays of loops of wire, bend light in
injected the particles into mice infected with the opposite direction to classical materials.
hepatitis B. The siRNA inhibited viral But these ‘metamaterials’ also absorb much
replication for up to seven days at doses low of the light’s energy, thereby clouding the
enough to avoid toxicity. Female mouse cells with Tsixdeletions view through the lens. To counter this
randomly inactivate one or both of their X problem, Steven Anlage and his colleagues
MATERIALS chromosomes or neither of them, whereas from the University of Maryland, College
Supermarket sweep female cells with extra copies of Tsixand Xite Park, built a metamaterial from
fail to initiate inactivation. superconducting niobium metals. Using
Nature Mater.doi:10.1038/nmat1434 (2005) this material led to significantly reduced
There is a potentially vast market for cheap DRUG DISCOVERY absorption in the lens, and to better
radio frequency identification tags — which Poor resistance imaging properties.
store information like barcodes, but can be
read by radio scanners. This is driving efforts Proc. Natl Acad. Sci. USA CHEMISTRY
to make tag components from organic doi:10.1073/pnas.0504952102 (2005) Step by step
materials that could be printed directly on to Compounds that inhibit the activity of kinase
packaging. A team from the University of enzymes have been used to treat some kinds J. Am. Chem. Soc.127,10462–10463 (2005)
Leuven, Belgium, has conquered one hurdle, of cancer with dramatic success. But a The stepwise growth of a single polymer chain
manufacturing a diode from the organic drawback of their clinical introduction has has been observed inside a ‘nanoreactor’.
compound pentacene that operates quickly been the rapid emergence of mutant drug- Hagan Bayley and Seong-Ho Shin of the
enough to process current in tags read by resistant kinases in treated patients. University of Oxford, UK, studied how
high-frequency radio signals. A research team led by Patrick Zarrinkar monomers link through the formation of
and David Lockhart from Ambit in San Diego bonds between sulphur atoms. The growing
GENETICS demonstrate a strategy that could help tackle polymer chain was anchored to (cid:1)-
Generation X this trend, which takes advantage of the haemolysin, a bacterial protein that acts as
tendency of kinase inhibitors to hit multiple a nanoreactor by shepherding the units
Science309,768–771 (2005) targets. The team screened various kinase into place. As the polymer grew, the
In female mammals, each cell shuts off one of inhibitors for their effects on three drug- conductance of the protein decreased,
its two X chromosomes.But how cells know resistant kinases. Although not designed to allowing the researchers to measure the
that they have multiple copies of the X is little act on these targets, some were effective lifetime of each intermediate over ten
understood. Now, Jeannie Lee of Harvard against the mutant kinases. Therapeutic extension steps.
Medical School in Boston, Massachusetts, deployment could be quick because these The authors suggest that the same
reports that the Tsixand Xitegenes seem to compounds are already in clinical technique could be used to study the kinetics
house the ‘counting’ mechanism. development. of other polymerization reactions.
of the process is immense. Everybody believed that axon the pattern of electrical activity
JOURNAL CLUB
A consensus on what drives pathfinding was driven by signals affects the expression of
Nicholas Spitzer nerves to their targets had slowly intrinsic to the cell, defined by guidance molecules, although
University of California, San Diego emerged from decades of work. regulatory proteins known as they have yet to demonstrate a
Then research by Gartz Hanson transcription factors, in concert connection with transcription
The co-director of the Kavli
and Lynn Landmesser at Case with certain external guidance factors. This work relies on an
Institute for Brain and Mind likes
Western Reserve University molecules. The evidence is intimate knowledge of the
novel work on neural wiring.
(Neuron43,687–701; 2004) upset strong — altering the expression patterns of activity in the embryo,
Like many scientists, I’m drawn to the apple cart. Previous studies of either component leads to which the researchers went to
big questions. And in neuroscience, suggested that electrical signalling altered wiring. some pains to collect.
one of the biggest is known as the played no part in the wiring Some of my own research had It is interesting that it’s the
wiring problem. This asks how the process, but these researchers find hinted at a role for electrical pattern of activity rather than the
nervous system is wired up during that spontaneous electrical activity signalling in pathfinding, but total amount that’s important,
embryonic development. With in chick embryos is necessary to Hanson and Landmesser discover and I am delighted to reorient my
100 billion neurons each making guide the projections of motor a link that makes their result thinking on the topic. Now, what
10,000 synapses, the complexity neurons (axons) to muscles. really powerful. They show that drives the spontaneous activity?
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Vol 436|4 August 2005
NEWS
Senator boosts chances
of stem-cell reform
WASHINGTON DC And whether or not the bill passes this year,
Prospects for US stem-cell research bright- they say, Frist’s speech marks a turning point in
ened considerably last week when a key the US debate on stem-cell research, because of
Republican senator backed the idea of loosen- his highly visible role in the Republican party
ing funding restrictions on the work. and the Senate. “The ramifications of this are
In a speech on the floor of the Senate on huge,” says Kevin Wilson, director of public
29 July, majority leader Bill Frist (Republican, policy at the American Society for Cell Biology.
Tennessee) endorsed efforts to increase federal Frist had said recently that he was opposed
funding for research on newly derived human to modifying the president’s policy, and his
embryonic stem-cell lines. He said that Presi- change of mind was a surprise to many people
dent George Bush’s policy of limiting the use of involved in the stem-cell debate. But Nature
federal funds to a handful of lines derived has learned that Frist consulted with at least
before 9 August 2001 needed changing. two scientists just days before his speech.
“I believe the president’s policy should be On 27 July, Frist spoke to Irving Weissman, a
modified,” Frist said. “We should expand fed- stem-cell pioneer at Stanford University and an
eral funding and current guidelines governing outspoken critic of the president’s policy.
stem-cell research, carefully and thoughtfully Weissman told him that the stem-cell lines cur-
staying within ethical bounds.” rently approved for research cannot be used for
Frist’s announcement makes it much more therapeutic trials in people because they are
likely that the Senate will pass legislation sim- probably contaminated with mouse viruses. He
ilar to that already passed by the House of Rep- also explained that US companies are likely to
resentatives, which voted to loosen funding need licences to develop therapies using the
restrictions in May (see Nature435,544–545; best techniques in the field, which have been
2005). Research advocates even say that Frist’s pioneered by South Korean researchers. Bill Frist heads for the Senate to announce his
speech might make it possible for the Senate “I told him that prohibiting a line of research support for changes to rules on stem-cell research.
to later override a promised presidential veto has consequences, not just from a scientific
of the bill — although the return of the bill perspective, but also from both economic and emphasis on the development of potential
to the House is unlikely to gather similar levels health perspectives,” Weissman says. treatments is encouraging, Weissman adds. “I
of support. The fact that Frist’s speech placed strong knew something was going to happen, but I
More falling foam puts shuttle programme in serious doubt
After an embarrassingly large chunk of foam Although the foam that came off McDonald argues that NASA should now cut
fell off the external fuel tank of the space Discovery’s tank last week didn’t hit the craft, its losses and stop shuttle flights for good.
shuttle Discovery during its 26 July launch, the size of the chunk, which weighed about Doug Osheroff, a physicist at Stanford
NASA has suspended further shuttle flights 400 grams, shows that despite all the effort University in California, and a member of
until the problem is solved. But as the agency the problem is as big as ever. the CAIB, agrees that small tweaks won’t
has already spent two years and well over Agency administrator Michael Griffin says help much, but major changes could take
$1 billiontrying to make the shuttle safe, it will be fixed “in short order”, and has put years. “We clearly don’t understand all the
critics say there will be no quick solution. together a ‘tiger team’ to look for answers. But mechanisms for foam shedding,” he says.
A similar piece of foam fell off Columbia’s many engineers question what NASA can do The best way for NASA to quickly reduce
fuel tank during take-off in January 2003. that it hasn’t tried already. “Unless there is a the risk to the shuttle crew is to fly with
The hole it punched in the shuttle’s wing significant redesign, there will always be a fewer people, Osheroff says. “There’s no
caused the craft to burn up on re-entry, safety issue with this foam,” says Henry reason to go up with seven astronauts.”
killing all seven astronauts inside. At the McDonald, former head of the NASA Ames As Naturewent to press, Discovery’s crew
insistence of the Columbia Accident Research Center in California, and now at was preparing to make emergency repairs,
Investigation Board (CAIB), NASA has the University of Tennessee at Chattanooga. unrelated to the foam incident, to the craft’s
poured resources into ensuring the safety of Developing new foam could take at least underside. For the latest news on the
future missions, in particular to secure the a year, he says, with redesigns to the tank shuttle’s progress, see www.nature.com/
insulating foam that prevents ice from taking even longer. As the ageing shuttle news/specials/returntoflight. ■
building up on the fuel tank. fleet is due to be decommissioned in 2010, Mark Peplow
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NATURE|Vol 436|4 August 2005 NEWS
M
O
C
IVORY-BILLED WS
WOODPECKER RAPS ON NE
Sound tapes convince OL./
H
critics that the extinct T
NI
bird has survived R
O
www.nature.com/news AB
MAGES Bone cells linked to creation N/CORNELL L
VILLA/GETTY I of fresh eggs in mammals G. M. SUTTO
DE
O
M
O
C. S A claim that stem cells in bone marrow and more radical. His team found that bone-mar-
blood can restock mammalian ovaries with row stem cells in both mice and women
eggs is raising hackles among reproductive express genes typical of germ cells. In mice,
biologists. If true, the finding opens up these genes cycle in unison with the same
avenues for delaying the menopause and markers in the ovary (J. Johnson et al.Cell
preserving fertility in female chemotherapy 122, 303–315; 2005). Tilly proposes that
patients. It also raises issues for women who these stem cells can travel to the ovaries, and
have had bone-marrow transplants, by that ovaries might signal to bone marrow, via
implying that subsequent children could be an unidentified factor, for new stocks of eggs.
the genetic offspring of the donor. “That factor could be of immense value
Supporters of the work, which is headed therapeutically,” he says, for example in treat-
by Jonathan Tilly at Harvard Medical ing premature menopause (see page 606).
School, have hailed it as a compelling chal- To test the idea, his team transplanted
lenge to the standard view of how ovaries bone marrow or blood cells to mice that
work. “I see amazing impli- were either genetically ster-
cations coming from this “The paper is an ile, or which had been given
work,” says Kutluk Oktay, a doses of chemotherapy that
outstanding challenge
physician at New York Pres- should destroy their eggs.
to a dogma.”
byterian Hospital who pio- Within two months of the
neered ovarian transplants bone-marrow transplants,
in women. But critics are dismayed that Tilly the researchers say, the mice regenerated
is already discussing the implications for hundreds of follicles — eggs encased by sur-
women when, they say, he has yet to prove rounding cells — at various stages of devel-
his case in mice. opment, that persisted for at least a year.
was surprised by how far he went,” he says. Tilly first caused a stir in 2004, when his “That was amazing,” says Tilly. And just 30
But Frist’s change of heart still leaves it team published a paper suggesting that hours after the blood transfusions, several
unclear whether he will give his full support to adult mouse ovaries can produce new eggs new eggs were visible.
the core measure of the proposed bill, which (J. Johnson et al.Nature428,145–150; 2004). Such rapid restocking leaves other
would allow researchers to use federal funds to The work countered the view that female researchers incredulous. Alan Trounson,
work on any embryonic cell lines. Frist said mammals are born with a store of eggs, and a stem-cell researcher at Monash University
that he supports research into methods of pro- that when the store runs low, the ovary shuts in Melbourne, Australia, says that the
ducing human embryonic stem-cell lines that down and menopause ensues. Biologists are quick appearance of eggs is unexpected and
don’t involve the use of a viable embryo. still debating the claim. “It has never been surprising.
In recent weeks, senators have proposed a reproduced as far as I am aware,” says Allan Critics also doubt whether the new eggs
flurry of bills supporting such methods — none Spradling, a developmental biologist at the come from the transplants. Tilly labelled his
of which has yet been shown to work (see Carnegie Institution in Baltimore. blood-transfusion cells with a protein that
Nature436,309; 2005). Naturehas been told Now, Tilly has proposed something even glows green, then showed the dye was pre-
that two senators, Kay Bailey Hutchison sent in the eggs. But Spradling says the eggs
(Republican, Texas) and Norm Coleman R/SPL could have absorbed the dye from the blood.
(Republican, Minnesota), have also suggested NE Tilly’s supporters argue that such scepti-
‘compromise’ bills. One would allow funding MEISS cism is an understandable reaction to a rad-
for research on cell lines created since the pres- H ical idea. “The paper is an outstanding
C
ident’s policy was announced until now. The GS challenge to a dogma,” says Oktay, adding
S.
other would allow researchers to use only ‘spare’ that the idea is consistent with his finding
embryos created for in vitrofertilization cur- that ovarian transplant patients seem to ovu-
rently existing at fertility clinics. late for longer than expected. “I don’t think
These bills could still pull Senate support any revolution could be bloodless.”
away from the core measure — passed by To prove the case, everyone agrees that Tilly
the House and favoured by most scientists. must produce baby mice from eggs that come
As majority leader, Frist gets to decide how from bone-marrow transplants or blood
and when to put each bill to the vote when transfusions. “We have tons of experiments
the Senate reconvenes next month after a under way to address this,” he told Nature.
long recess. ■ Follicles may regenerate and produce new eggs, “Should we show that, it’s case closed.” ■
Erika Check thanks to stem cells in bone marrow and blood. Claire Ainsworth
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