Science (Vol. 307, No. 5707, January 2005)

117 Pages·2005·9.428 MB·English

by  Donald (Ed) Kennedy

14 January 2005

Volume 307
Number 5707

Testing Hypothesis Strength
New Drug Hope for TB
Spintronic Theory Confirmed
Hormone Determines Heart Size
Epilepsy Drugs Lengthen Worm Life-Span

RESEARCH

This Week in Science
Caged Gas * New Tool for the TB Armory * Variation on a Theme * Spin Switching Nanomagnets *
Tuning Superatom Chemistry * A Tamed Radical * Resolved Bump * An Albatross's Life * Retinoic Acid
and Heart Development * Gut Antigen Sampling and Host Defense * Anticonvulsant Medications and
Aging in Worms * Another Route to Stat Regulation * Testing the Strength of Hypothesis * Directions
Home * A Clock by Another Mechanism * Form and Function? 177
Editors' Choice: Highlights of the recent literature
APPLIED PHYSICS: Chip-Scale Magnetic Measurements * NEUROSCIENCE: Making Memories *
CLIMATE SCIENCE: Twinned Thinning * CHEMISTRY: Maintaining Chains * ECOLOGY/EVOLUTION:

Eats Roots or Shoots * BIOTECHNOLOGY: Library Science * STKE: Specificity Through Degradation
182
Review
Testing Hypotheses: Prediction and Prejudice
Peter Lipton 219-221.
Brevia
The First Glacial Maximum in North America
Greg Balco, Charles W. Rovey, II, and John O. H. Stone 222.
Research Article
A Diarylquinoline Drug Active on the ATP Synthase of Mycobacterium tuberculosis
Koen Andries, Peter Verhasselt, Jerome Guillemont, Hinrich W. H. Göhlmann, Jean-Marc Neefs, Hans
Winkler, Jef Van Gestel, Philip Timmerman, Min Zhu, Ennis Lee, Peter Williams, Didier de Chaffoy,
Emma Huitric, Sven Hoffner, Emmanuelle Cambau, Chantal Truffot-Pernot, Nacer Lounis, and Vincent
Jarlier 223-227.
Reports
I
Time-Domain Measurements of Nanomagnet Dynamics Driven by Spin-Transfer Torques
I. N. Krivorotov, N. C. Emley, J. C. Sankey, S. I. Kiselev, D. C. Ralph, and R. A. Buhrman
228-231.

Al Cluster Superatoms as Halogens in Polyhalides and as Alkaline Earths in Iodide Salts
D. E. Bergeron, P. J. Roach, A. W. Castleman, Jr., N. O. Jones, and S. N. Khanna 231-235.

A Stable Aminyl Radical Metal Complex
Torsten Büttner, Jens Geier, Gilles Frison, Jeffrey Harmer, Carlos Calle, Arthur Schweiger, Hartmut
Schönberg, and Hansjörg Grützmacher 235-238.

Encapsulation of Molecular Hydrogen in Fullerene C by Organic Synthesis
60
Koichi Komatsu, Michihisa Murata, and Yasujiro Murata 238-240.

Corrected Late Triassic Latitudes for Continents Adjacent to the North Atlantic
Dennis V. Kent and Lisa Tauxe 240-244.

An Astronomical 2175 Å Feature in Interplanetary Dust Particles
John Bradley, Zu Rong Dai, Rolf Erni, Nigel Browning, Giles Graham, Peter Weber, Julie Smith, Ian
Hutcheon, Hope Ishii, Sasa Bajt, Christine Floss, Frank Stadermann, and Scott Sandford
244-247.

Retinoic Acid Signaling Restricts the Cardiac Progenitor Pool
Brian R. Keegan, Jessica L. Feldman, Gerrit Begemann, Philip W. Ingham, and Deborah Yelon
247-249.

Global Circumnavigations: Tracking Year-Round Ranges of Nonbreeding Albatrosses
John P. Croxall, Janet R. D. Silk, Richard A. Phillips, Vsevolod Afanasyev, and Dirk R. Briggs
249-250.

No Transcription-Translation Feedback in Circadian Rhythm of KaiC Phosphorylation
Jun Tomita, Masato Nakajima, Takao Kondo, and Hideo Iwasaki 251-254.

CX3CR1-Mediated Dendritic Cell Access to the Intestinal Lumen and Bacterial Clearance
Jan Hendrik Niess, Stephan Brand, Xiubin Gu, Limor Landsman, Steffen Jung, Beth A. McCormick, Jatin
M. Vyas, Marianne Boes, Hidde L. Ploegh, James G. Fox, Dan R. Littman, and Hans-Christian Reinecker
254-258.

Anticonvulsant Medications Extend Worm Life-Span
Kimberley Evason, Cheng Huang, Idella Yamben, Douglas F. Covey, and Kerry Kornfeld
258-262.

Self-Propagating, Molecular-Level Polymorphism in Alzheimer's ß-Amyloid Fibrils
Aneta T. Petkova, Richard D. Leapman, Zhihong Guo, Wai-Ming Yau, Mark P. Mattson, and Robert
Tycko 262-265.

Semaphorin 3E and Plexin-D1 Control Vascular Pattern Independently of Neuropilins
Chenghua Gu, Yutaka Yoshida, Jean Livet, Dorothy V. Reimert, Fanny Mann, Janna Merte, Christopher
E. Henderson, Thomas M. Jessell, Alex L. Kolodkin, and David D. Ginty 265-268.

II
Stat3 Dimerization Regulated by Reversible Acetylation of a Single Lysine Residue
Zheng-long Yuan, Ying-jie Guan, Devasis Chatterjee, and Y. Eugene Chin 269-273.

COMMENTARY

Editorial
The Science of Social Diseases
Christopher Dye 181.
Letters
Retraction Owen N. Witte, Janusz H. Kabarowski, Yan Xu, Lu Q. Le, and Kui Zhu ; Scientific Priorities
in North Korea Courtland Robinson, Myung-Ken Lee, Gilbert Burnham;, and Norman P.
Neureiter ; North Korea and Renewable Energy David F. Von Hippel and Peter Hayes ; Inflammation
and Life-Span Calogero Caruso, Giuseppina Candore, Giuseppina Colonna-Romano, Domenico Lio,
Claudio Franceschi;, Anthony G. Payne;, Caleb E. Finch, and Eileen M. Crimmins 206.
Policy Forum
ECOLOGY:
The Convention on Biological Diversity's 2010 Target
Andrew Balmford, Leon Bennun, Ben ten Brink, David Cooper, Isabelle M. Cue, Peter Crane, Andrew
Dobson, Nigel Dudley, Ian Dutton, Rhys E. Green, Richard D. Gregory, Jeremy Harrison, Elizabeth T.
Kennedy, Claire Kremen, Nigel Leader-Williams, Thomas E. Lovejoy, Georgina Mace, Robert May,
Phillipe Mayaux, Paul Morling, Joanna Phillips, Kent Redford, Taylor H. Ricketts, Jon Paul Rodríguez,
M. Sanjayan, Peter J. Schei, Albert S. van Jaarsveld, and Bruno A. Walther 212-213.
Books et al.
HISTORY OF SCIENCE: Lost in Translation?
Stuart McCook 210-211.
MARINE ECOLOGY: Voice of the Turtle
Fredric J. Janzen 211.
Perspectives
MICROBIOLOGY: Enhanced: TB--A New Target, a New Drug
Stewart T. Cole and Pedro M. Alzari 214-215.
APPLIED PHYSICS: A Ringing Confirmation of Spintronics Theory
Mark Covington 215-216.
CHEMISTRY: Odd Electron on Nitrogen: A Metal-Stabilized Aminyl Radical
Wolfgang Kaim 216-217.
CELL SIGNALING: Stat Acetylation--A Key Facet of Cytokine Signaling?
John J. O'Shea, Yuka Kanno, Xiaomin Chen, and David E. Levy 217-218.

NEWS

News of the Week
ATMOSPHERIC SCIENCES: NOAA Loses Funding to Gather Long-Term Climate Data
Jeffrey Mervis 188.
RAINFALL MONITORING: Report Bucks NASA's Plan to End Mission
Andrew Lawler 189.
CLINICAL TRIALS: Facing Criticism, Industry Offers to Share Data
Jennifer Couzin 189.
INFECTIOUS DISEASE: Polio Eradication Effort Adds New Weapon to Its Armory
Leslie Roberts 190.
SOUTH ASIA TSUNAMI: U.S. Clamor Grows for Global Network of Ocean Sensors
III
Eli Kintisch 191.
PALEONTOLOGY: New Fossils Show Dinosaurs Weren't the Only Raptors
Erik Stokstad 192.
ITALY: Synchrotron Staff Protests Funding Cuts
Alexander Hellemans 192.
BIOMEDICINE: As the Worm Ages: Epilepsy Drugs Lengthen Nematode Life Span
Ingrid Wickelgren 193.
ACADEMIC AFFAIRS: Plan for Chiropractic School Riles Florida Faculty
Yudhijit Bhattacharjee 194.
DEVELOPMENTAL BIOLOGY: Bird Wings Really Are Like Dinosaurs' Hands
Elizabeth Pennisi 194.
STEM CELLS: California's Bold $3 Billion Initiative Hits the Ground Running
Constance Holden 195.
News Focus
DRUG SAFETY: Gaps in the Safety Net
Jennifer Couzin 196-198.
RADIATION HAZARDS: Kyrgyzstan's Race to Stabilize Buried Ponds of Uranium Waste
Richard Stone 198-200.
SOUTH ASIA TSUNAMI: Failure to Gauge the Quake Crippled the Warning Effort
Richard A. Kerr 201.
AMERICAN GEOPHYSICAL UNION MEETING: A Lively Core Turns Mercury Into an
Enormous Electromagnet
Richard A. Kerr 202.
AMERICAN GEOPHYSICAL UNION MEETING: What's Going On in Saturn's E Ring?
Richard A. Kerr 202-203.
AMERICAN GEOPHYSICAL UNION MEETING: Scary Arctic Ice Loss? Blame the Wind
Richard A. Kerr 203.
AMERICAN GEOPHYSICAL UNION MEETING: Snapshots From the Meeting
Richard A. Kerr 203.
Departments
Quarterly Author Index 1-12.
Products
NEW PRODUCTS 274.
NetWatch
EXHIBITS: A Century of Relativity * DIRECTORIES: Is There a Cartographer in the House? *

RESOURCES: Answering Age-Old Questions * DATABASE: Atomic Alter Egos 187
ScienceScope
Perchlorate Study Suggests Lower Risk * Is NASA Ready for Readdy? * Swansea U. Goes Deep Into

Supercomputing * NIH Wants More Pioneering Women 191
Random Samples
A Clean Sweep * Monumental Makeover * Primordial Fungus * Jobs * Honors * Deaths

204

IV
T W
HIS EEK IN
edited by Stella Hurtley and Phil Szuromi
New Tool for the TB Armory
clusters can form with a distinct number of valence-electrons
There is an urgent need for new drugs to combat the advancing (one such shell occurs at 40 electrons).Bergeron et al. (p.231)
scourge of tuberculosis that is inexorably linked with the HIV epi- build on recent work showing that Al I− forms such a superatom.
13
demic.Andries et al.(p.223,published online 9 December 2004;see They now show that Al cluster anions bearing an even number
13
the cover and Perspective by Coleand Alzari) have developed a lead of iodine atoms show halogen-like stability,and that Al cluster
14
compound from a series of recently patented anions bearing an odd number of iodine
diarylquinolines,known as R207910.This atoms show an alkaline earth–like stability.
compound has good selectivity and potency The delineation of these additional families
Caged Gas
for several mycobacterial species,including indicates that other superatom systems
Mycobacterium tuberculosis, and retains Endohedral fullerenes contain guest may also be realized.
activity against M. tuberculosisstrains that atoms or molecules within their cages
are singly or multiply resistant to com- that are trapped during the synthesis of
A Tamed Radical
monlyused drugs.In contrast to other anti- the fullerene. Komatsu et al. (p. 238)
mycobacterial drugs,R207910 targets an show that a C derivative that contained Radicals,or compounds in which a single
60
adenosine triphosphate synthase.R207910 a large opening (a 13-membered ring) electron is missing from the valence shell
enhanced mycobacterial killing in a mouse could be closed in a series of synthetic of one of the atoms, act as short-lived
model of established infection compared steps. In this manner, they are able to intermediates in many chemical reactions.
with isoniazid,rifampicin,or pyrazinamide, create C trapping H in high yield. A series of important oxidative enzymes
60 2
which are used in current therapeutic regi- stabilize O-centered phenoxyl radicals by
mens.It is hoped that this new drug candi- coordination to a transition metal in the
date will allow the treatment of tuberculosis active site.Whether a comparable mech-
in as little as 2 months. anism pertains with N-centered radicals
has been an open question.Now Büttner
et al.(p.235;see the Perspective by Kaim)
Variation on a Theme
have prepared a rhenium complex with a
The semaphorins and their plexin-neuropilin coordinated N-centered aminyl radical.The
coreceptors are established players in axon complex is stable as a solid and in a room-
guidance.More recently,they have also been temperature solution.Spectroscopy,theory,
implicated in vascular development.Gu et al. and its reactivity supports a structure in
(p.265,published online 18 November 2004) which it is mainly N,not the metal center,
report that semaphorin 3E (Sema3E) does that has lost an electron,consistent with
not require neuropilin as a coreceptor in radical stabilization by the rhenium.
patterning the developing mouse vascular
system,but instead interacts directly with
Resolved Bump
the plexin-D1-expressing cells.The repulsive
effect of Sema3E-bearing somites on vas- Astronomers have repeatedly noted a 2175
cular endothelial cells expressing plexin-D1 angstrom extinction feature (or bump) in
was observed in the absence of neuropilins, spectra of dust in the interstellar medium.
indicating that neuro- pilins are not,after all, The unknown source of this bump must be
obligatory semaphorin coreceptors in mammalian vasculogenesis. the most abundant species in the interstellar medium,as the feature
is ubiquitous.Bradley et al.(p.244) identified organic carbon and
amorphous silica-rich material as the carriers of the 2175 angstrom
Spin Switching Nanomagnets
bump in laboratory spectra of interplanetary dust particles that were
Injecting a polarized spin current into a magnetic material can exert collected in Earth’s stratosphere.
a torque on the magnetic moment,causing it to precess.Under the
right conditions,the magnetic moment can be flipped,potentially
An Albatross’s Life
allowing electrically controlled magnetic memories. However,
details of the dynamics of this precession and switching have been Albatrosses are well known for their extreme wide ranging foraging
lacking.Kirivortov et al.(p.228;see the Perspective by Covington) trips around the Southern Ocean from their colonies during the
now present a time-domain technique for looking at these processes. breeding season. Using leg-mounted loggers on 22 individual
Using a magnetic nanopillar sandwich structure,they show that the gray albatrosses over periods of 18 months,Croxall et al.(p.249)
precession and magnetic reversal processes are coherent processes provide evidence of the spectacular circumpolar migrations of
driven by polarized spin injection. albatrosses and reveal the underlying structure and strategies of
these journeys. Migration strategies differed between individual
birds. Some regularly circumnavigated the globe, while others
Tuning Superatom Chemistry
ET AL.U Much of chemical reactivity can be understood in terms of the driving etoit hae rre rgeimona iinne dth ien Itnhdei avnic iOnicteya onf. tAhlbe abtrreoesdseinsg a grero aumndosn ogr tmheig mratoesdt
MATS force provided by the stability of bonding arrangements that provide endangered of all pelagic seabirds,and these data help to identify
O
K each atom with a closed atomic shell of electrons.For small atomic the critical habitats where protection is most required.
CREDIT: clusters,the so-called “jellium”model predicts that stable superatom CONTINUEDONPAGE179
www.sciencemag.org SCIENCE VOL 307 14 JANUARY 2005 177
Published by AAAS
it takes
T W
CONTINUEDFROM177 HIS EEK IN
both sides of
the brain.
Retinoic Acid and Heart Development
Model systems such as the zebrafish heart can be used to shed light on the normal
development and function of the cardiac system in vertebrates and to assist in our
understanding of heart injury and disease. Retinoic acid is critical for late steps in
heart development,including terminal myocardial differentiation,cardiac looping,and
ventricular maturation and growth.Using zebrafish genetics and embryology,Keegan
et al.(p.247) now show that there is also an early function of retinoic acid in cardiac
specification. Retinoic acid signaling is involved in selecting the number of cardiac
progenitors from within a multipotential pool,and organ size is controlled by retinoic
acid-mediated restriction of the early cardiac progenitor pool.
Gut Antigen Sampling and Host Defense
A complex interplay has evolved between the cells of the immune system and the
mucosal barrier that interfaces with the intestinal lumen and its contents.A good
example of this are the specialised antigen-presenting
CALL FOR ENTRIES
dendritic cells (DC) that reside below the intestinal
epithelium “sampling” luminal contents via dendritic
Science & Engineering
extrusions as they extend through the epithelial barrier.
Niess et al. (p.254) examined the behavior and activity Visualization Challenge
of these myeloid-derived DC.The DC were regulated in
the extrusion of trans-epithelial dendrites and in their
phagocytic activity by the chemokine receptor CX3CR1.
When theleft braincollaborates with
Loss of these activities in the absence of CX3CR1 corre-
the right brain, science merges with
lated with an increase in susceptibility to Salmonella
art to enhance communication and
typhimurium, suggesting a direct link between trans-
understanding of research results—
epithelial sampling of antigen by DC and immune-
illustrating concepts, depicting
mediated protection of the intestinal mucosa. phenomena,drawingconclusions.
TheNationalScienceFoundationand
Anticonvulsant Medications and Aging in Worms Science, published by the American
Association for the Advancement of
Drugs used to treat human seizures have been found to extend the life-span of worms.
Science, invite you to participate in
Evason et al.(p. 258; see the news story by Wickelgren) report that adult worms the annual Science and Engineering
exposed to three structurally similar anticonvulsant drugs had a life-span increase of VisualizationChallenge.Thecompetition
nearly 50%. In addition to delaying age-related degenerative changes in worms, the recognizes scientists,engineers, visu-
drugs also increased neuromuscular activity, a behavior associated with increased alization specialists, and artists for
life-span in the worm.The drugs may act by a common mechanism both to affect producingor commissioninginnova-
neural activity and aging,and provide potential leads as therapeutics to treat human aging. tive workin visualcommunications.
ENTRYDEADLINE:
Another Route to Stat Regulation May 31, 2005
AWARDSCATEGORIES:
Stats (signal transducers and activators of transcription) efficiently carry information from
Photos/StillImages,Illustrations,
cell surface cytokine receptors (which cause Stat phosphorylation) to the nucleus (where
Explanatory Graphics,Interactive
Stats work as transcriptional activators).Yuan et al.(p.269;see the Perspective by O’Shea et
Media,Non-interactivemedia
al.) report that Stat3 is also regulated by acetylation of a specific lysine residue.Stat3
associated with the transcriptional coactivators CBP and p300,which have histone acetyl- COMPLETEINFORMATION:
www.nsf.gov/od/lpa/events/sevc
transferase activity and can modify Stat3 in vitro.Acetylation of the key lysine residue
appears to be required for dimerization of Stat3 and for transcriptional activation of genes in Awards ineachcategory willbepublished
cells treated with the cytokine,oncostatin M.Cells expressing a mutant form of Stat3 that is in theSeptember 23, 2005issueof
not acetylated were insensitive to gene regulation and growth promotion by oncostatin M. ScienceandScienceOnlineand
displayedon theNSF website.
Testing the Strength of Hypothesis
Whether a hypothesis gets credit for predicting new data versus for when it merely accommo-
dates old data is a controversial matter among philosophers of science. Lipton
(p.219) reviews several attempts to answer this question before presenting his own arguments
ET AL.NIESS as to how and why the ability to predict trumps the ability to accommodate existing data. Accept thechallenge.
CREDIT: Show how you’vemastered
theart of understanding.
www.sciencemag.org SCIENCE VOL 307 14 JANUARY 2005
Published by AAAS
E
DITORIAL
The Science of Social Diseases
T
he misery of life for many inhabitants of the former Soviet Union has been made shockingly plain by a
grim succession of health statistics. One of the most thoroughly documented phenomena is the high
death rate of young and middle-aged Russian men, linked to poor nutrition, alcoholism, cardiovascular
disease, the resurgence of syphilis and tuberculosis (TB), and the spread of AIDS. This catalog of ill
health is not merely a list of different ailments with separate causes, it is symptomatic of large-scale social
disruption, with elements including poor education, psychological stress, rising crime and violence, high
rates of unemployment, and a very unequal distribution of income among those employed.
Among these “social diseases,” TB plays a leading role as the ubiquitous indicator of failing health and health
services. Remarkably, Soviet health reporting systems remained intact through the turmoil of the 1990s. As a result,
we know that the TB incidence rate roughly trebled in Russia between 1990 and 2000,
approaching 0.1% annually by the turn of the millennium (see www.who.int/tb). A similar
thing happened in all the ex-Soviet states, but not in central Europe. No one has dared to
forecast how much worse the resurgent TB epidemic will get. However, as a key indicator
of population health at the European Union’s eastwardly mobile frontier, TB trends are
being closely watched.
Against this dark background, a few bright spots are visible in the latest surveillance
statistics. The 2003 data confirm that TB incidence rates in Belarus, Estonia, Latvia,
Lithuania, and Russia have been falling for the past 3 to 4 years. Although this is reassuring,
there will be some hesitation in accepting that the worst is over as long as the data cannot
explain why. Was it because revitalized TB control programs stopped disease transmission?
Or because a general recovery in population health lowered susceptibility to TB? Or did
the new epidemic exhaust the supply of susceptible people to infect? Russia had actually
taken steps to contain TB by 1994, when reviving treatment programs cut patient death
rates. The downturn in incidence since 2000 could be the delayed effect of preventing
transmission. On the other hand, the same epidemiological pattern is seen in several
newly independent states, indicating that wider epidemiological processes are at work.
Wealth appears to be relevant, because the fall in incidence is more conspicuous in the
richer states of Soviet Europe than in the poorer countries of central Asia.
The general problem is that we often cannot know to what extent large-scale interventions contribute to observed
improvements in health, because these interventions are not carried out as controlled experiments. In this context, a
blueprint for reaching the UN Millennium Development Goals, to be submitted to the United Nations Secretary
General on 17 January this month, will recommend a battery of specific actions to alleviate poverty. The scientific
hitch is that we may never be able to prove that they succeeded, even if they are all implemented. The same difficulty
faces those who will evaluate the success of the $150 million World Bank loan to Russia for TB and AIDS control
and the large-scale projects now supported by the Global Fund to Fight AIDS, Tuberculosis and Malaria. The
strength of the link between cause and effect will depend, in part, on how convincingly we can generalize from the
original experimental proof.
Despite the complex interactions between TB and various social, biological, and economic factors, there is at least
one simple message for those who are devising new health technologies. It is that without effective systems for
delivery, new tools will be of little value. For instance, a new kind of drug to treat TB, such as the one reported by
Andries et al. in this issue (see also the Perspective by Cole), would undoubtedly be a huge step forward, especially in
the treatment of drug-resistant disease. But patients must want it and health services must be able to provide it. From
Vilnius to Vladivostock, the typical TB sufferer is, in some combination, male, unemployed, alcoholic, HIV-positive,or
in prison. The science required to make technology work in this and other social settings is tractable and could be
hugely beneficial. But scientists, like patients and physicians, need incentives, and operational research remains an
N undervalued, and therefore underexploited, discipline.
O
OLLIS Christopher Dye
NE/J.M CSwhriitszteorplahnedr. Dye is coordinator of Tuberculosis Monitoring and Evaluation at the World Health Organization,CH-1211 Geneva 27,
MAGAZI 10.1126/science.1109116
ORS
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O/STB/C
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www.sciencemag.org SCIENCE VOL 307 14 JANUARY 2005 181
Published by AAAS
E C
DITORS’ HOICE
HIGHLIGHTS OF THE RECENT LITERATURE
edited by Stella Hurtley
cause of the observed
APPLIED PHYSICS thinning and find that the
Chip-Scale Magnetic Measurements thinning of coastal ice shelves
is transmitted rapidly to the
The ability to measure tiny magnetic fields with good sensitivity can be found in many appli- grounded ice streams above,
cations,from biological imaging to prospecting for buried treasure.However,the most sensitive revealing a tight coupling
magnetometers that operate in ambient conditions tend to be power-hungry,bulky,and heavy. between the ice sheet
Shrinking the size to just several millimeters and the power consumption to hundreds of milli- interior and surrounding
watts,Schwindt et al.have fabricated a sensitive magnetometer using microelectromechanical ocean.— HJS
technology. A cloud of rubidium atoms Geophys.Res.Lett.31,
trapped in a micromachined vapor cell is 10.1029/2004GL021106;
used to sense the magnetic field.The mag- 10.1029/2004GL021284 (2004).
netic field splits the energy levels of rubid-
ium atoms,and the extent of the splitting CHEMISTRY
depends on the strength of the magnetic Maintaining Chains
field. Changes in the magnetic field are
then detected and tracked optically by the Coupling reactions of organic
relative absorption changes of a laser light molecules on surfaces can
tuned to the split energy levels.It could proceed at modest tempera-
be that in the not-too-distant future we tures.McCarty and Weiss
could be using handheld battery-operated have used low-temperature
magnetometers.— ISO scanning tunneling microscopy
The miniaturized magnetometer. Appl.Phys.Lett.85,6409 (2004). (STM) to observemolecules
aligning into chains before
such reactions can proceed.
NEUROSCIENCE activation promoted nuclear majority of the ice mass lost At room temperature,
Making Memories accumulation of importin. presently from the WAIS flows diiodobenzene dissociates on
The changes in importin to the sea as ice streams,of the atomically flat Cu(111)
During learning,in a process distribution were not which that of Pine Island surface to create mobile
termed long-term potentiation observed when only short- Glacier is the most important. phenylene radicals that can
or long-term facilitation, term synapticchanges were The Pine Island Glacier,and be pinned at defect sites.
synapses are specifically modi- induced (changes that are the adjoining ice shelves of Images taken at 77 kelvin
fied by a process that involves known not to involve changes Pine Island Bay,have thinned show that the phenylene
tsf—arryxoanosnmaenspp c tosraheirrpe adit tntiesoeeennduldf. r bBroiisyetn aecatta—hl u aecs t edeehli llseto tnh nnaeungeccauleetreoudns itmmtnroa ea tbnymreas blo noderscey caam-rstirpsieonotlngaicos tiitanemrtd)ae.p tIsdoteu rdwrbte siiwmntthrshaa, ititbcnhehuses t s3paainra gdepdne ee iecfxraifsacfd,eamtecnhsittne.slI ye enod xo ft. tvtwSehehnoreet strspehe,h leccaea htpruedaasdn seetgts e ,asl. sbtpipohpeen ccndoiyeeulsdel d anc lhebig aemni nu oissnn—e nodom tthnoeec rp oS ouvTulalM ltae onft ly 10.1021/JA038930G (2004)
must possess mechanisms to a role for the classical nuclear use satellite data altimetry to OC.
transmit synaptically activated import pathway in generating document how ice shelves in M.S
second messengers and tran- long-lasting memories seems that region have thinned,and CHE
M.
sTaAcshprpoliyepmsctiitasoson sone ff nea tstch otaiorsly. rps nna otetowhu iwr tdosain synss u eianccnltedu isn. lCikLeIlyM.—AT SEM SHNCeIuEroNn 4C4,E997 (2004). tmowhcaeeerlyamt inane tcgrtu rtcirhabraesuenntde tfs rbt ethyehe zta ihttnh eagi nra oencn ti0ni o.5gn °t Coof ET AL.,J.AM) WEISS
mouse hippocampal neurons. Twinned Thinning average.The pattern of shelf OTTO
I(ntnpyu rpbcoelotestea)hi rna cipsma pisnpeevaosor ri ltmtv oienp db om eirn tai innanvcysot cilvveeelld. TAtohn egta lrorecbstapiclo wnIcsaeer m Sohfien teght ei s( WW ofeA sgItSre) at tgisnhergonin ustnihntiadinvtege Ad mt ntoirt riacbrrhoucarttsnia ctgr hiiiecnasegt, isocsulf im gmtghoaeertsieert-s Phenylene chains hang 85,6409 (2004);(B
Iimn bpootrhti ntys pweesr oe ff onuenudro lnosc,alized ctoo nmceerltn c boemcapulestee,liyf ,iitt wise lraer ge tPhaaynn ep eret vailo.utesslyt tthheo uhgyhpot.thesis tsotegpest.her,even over surface HYS.LETT.
aaSnltoidmn igun l ais xytohnnaastp tatirncigd cg odemerenpdda rlriottmnesge -nts. eampnaposrusogivxheim tmoa etrealtliiysne 7g s imesa .u Slneulvickehel lbyy tbah yna tuth mtehe earsdiecj aoclhi niacinnegg-ef olso cawerea m ntr,oiugdgseienlr tgeod tchoev ecrhaagine.sA,at hseigchoenrd s luaryfearc e ET AL.,APPL.P
DT
lasting facilitation in Aplysia to occur soon;nevertheless, simulate its effects on the of chains can align on a WIN
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Similarly,in hippocampal of sea level rise due to accel- that recent increases in local the upper-level chains could DITS:(T
neurons synaptic receptor erated ice loss.The great ocean temperature are the be nudged to new locations CRE
182 14 JANUARY 2005 VOL 307 SCIENCE www.sciencemag.org
Published by AAAS
on the surface,where they would return competitive interactions among the
to their original length by recruiting more plant species within the communities,
monomer units.— PDS eventually producing the nonadditive
J.Am.Chem.Soc.126,16672 (2004). effects observed.Differential distributions
of above- and below-ground herbivores
ECOLOGY/EVOLUTION may well contribute to locally hetero-
Eats Roots or Shoots geneous diversity levels.— AMS
Ecol.Lett.8,30 (2005).
Recently,plant ecologists have increasingly
focused on the role of soil organisms in BIOTECHNOLOGY
determining plant community processes. Library Science
Below-ground herbivores,such as worms,
tend to promote plant diversity when they Bacteria are everywhere and can eat
feed on dominant plant species.However, just about anything,including such
van Ruijven et al.show that the combined unappetizing fare as petroleum sludge.
effects of above- and below-ground Therefore,they must possess the
herbivores cannot be predicted from their enzymes (and the genes encoding the
separate effects.Different combinations of enzymes) that catabolize hydrocarbons.
invertebrate herbivores (nematodes and In the past,the challenge has been to
identify and cultivate the desired species;
advances in technology have made it
feasible to bypass cultivation and to
browse for specific genes (enzyme
activities) in metagenome (expression)
libraries.Uchiyama et al.take the next
step in devising a method of sorting the
library contents on the basis of substrate
specificity and then searching for genes
of interest.Their approach succeeds
because bacteria rely on gene regulatory
Experimental plot. networks (and even riboswitches) that,
in many cases,are induced or repressed
wireworms below ground,and grasshoppers by small molecules—either the substrate
above ground) were added to experimental itself or chemically related compounds.
species-rich grassland plant communities. Starting with a metagenome library
When added separately,the nematodes and made from petroleum-contaminated
wireworms had positive effects on diversity, groundwater,they end up with a P450
whereas the grasshoppers had neutral enzyme that catalyzes hydroxylation
effects.When added together,however,the (which makes hydrocarbons more polar
combined effect on diversity was negative. and amenable to catabolism) of
The different feeding preferences of the two 4-hydroxybenzoate.— GJC
groups of herbivores appeared to alter the Nature Biotechnol.23,88 (2005).
HIGHLIGHTED IN SCIENCE’S SIGNAL TRANSDUCTION KNOWLEDGE ENVIRONMENT
Specificity Through Degradation
Yeast use partially overlapping kinase modules to specify
discrete cellular responses.For example,the upstream kinases
in the mitogen-activated protein kinase (MAPK) cascade,
Ste11 and Ste7,are both activated during mating response signaling and during
filamentous growth signaling.The MAPK Kss1 then triggers the filamentous growth
transcriptional cascade and the MAPK Fus3 triggers the mating response genes.In
the absence of Fus3,pheromone signaling stimulates Kss1 and filamentous growth
N
DO gene expression,suggesting that Fus3 has a role in suppressing filamentous growth
N
LO responses during pheromone signaling.Chou et al.and Bao et al.now report that
N,IMPERIAL COLLEGE, FgTdurheossewt3 aa ttbbhriu,ilgiTnzegdaceat1irnos,cn tteo hr eoemqf duaTeiierngcet1rdaa idFdnuea sscti3rigoe nbanaus lteoi ndnf g oaa ts f tptKreeasrcsn 1imsf.icTcareititpciyn1t gti Toh shnrtor i2fmua7guc3htl a owttrhae ersde p sqbhhyuao irpsreephddhe oMrforoAymrlP aofKtinle apedma abtenhyndw Ft uatohsyu3isss..
VE Degradation was mediated by a SCF ubiquitin ligase complex.Thus,selective
UIJ
R degradation of a transcriptional regulator represents a mechanism for generating
N
VA specificity during intracellular signaling.— NG
DITS:J. Cell 119,981 (2004).
CRE
www.sciencemag.org SCIENCE VOL 307 14 JANUARY 2005
Published by AAAS