Tạp chí khoa học số 2005-09-16

Table of Contents 16 September 2005 Volume 309 Science in Iran Number 5742 Adaptive Insect Immunity? Stronger Hurricanes to Come? Mouse Hormone Prolongs Life RESEARCH This Week in Science Blow Me Down * Klotho for Eternal Youth? * Right After the Burst * Stronger Under Pressure * Adaptive Immunity in Insects? * Rings of Uranium * Connecting Craters * Evolving Sequence and Expression * Protein Sequence Structure Prediction * Temporal Controls in Inflammatory Responses * SARS Spike, Up Close and Personal * New Salt * Two Ways to Longer Life (for Yeast) * DNA Damage Comes to Light 1785 Editors' Choice: Highlights of the recent literature MATERIALS SCIENCE: Large Nanotemplates * IMMUNOLOGY: Diabetes on Display * BIOCHEMISTRY: Some Like It Briny * PSYCHOLOGY: A Cooling-Off Period * ECOLOGY/EVOLUTION: Bleaching in Hot Water * CHEMISTRY: Site-Specific Catalysis * STKE: Fateful Feedback 1790 Brevia Characterization of a Phytophthora Mating Hormone Jianhua Qi, Tomoyo Asano, Masashi Jinno, Kouhei Matsui, Keisuke Atsumi, Youji Sakagami, and Makoto Ojika 1828 Research Article Suppression of Aging in Mice by the Hormone Klotho Hiroshi Kurosu, Masaya Yamamoto, Jeremy D Clark, Johanne V Pastor, Animesh Nandi, Prem Gurnani, Owen P McGuinness, Hirotaka Chikuda, Masayuki Yamaguchi, Hiroshi Kawaguchi, Iichiro Shimomura, Yoshiharu Takayama, Joachim Herz, C Ronald Kahn, Kevin P Rosenblatt, and Makoto Kuro-o 1829-1833 Reports Bright X-ray Flares in Gamma-Ray Burst Afterglows D N Burrows, P Romano, A Falcone, S Kobayashi, B Zhang, A Moretti, P T O'Brien, M R Goad, S Campana, K L Page, L Angelini, S Barthelmy, A P Beardmore, M Capalbi, G Chincarini, J Cummings, G Cusumano, D Fox, P Giommi, J E Hill, J A Kennea, H Krimm, V Mangano, F Marshall, P Mészáros, D C Morris, J A Nousek, J P Osborne, C Pagani, M Perri, G Tagliaferri, A A Wells, S Woosley, and N Gehrels 1833-1835 Molecular Octa-Uranium Rings with Alternating Nitride and Azide Bridges William J Evans, Stosh A Kozimor, and Joseph W Ziller 1835-1838 Ultrahigh Strength in Nanocrystalline Materials Under Shock Loading Eduardo M Bringa, Alfredo Caro, Yinmin Wang, Maximo Victoria, James M McNaney, Bruce A Remington, Raymond F Smith, Ben R Torralva, and Helena Van Swygenhoven 1838-1841 Influence of the Atlantic Subpolar Gyre on the Thermohaline Circulation Hjálmar Hátún, Anne Britt Sandø, Helge Drange, Bogi Hansen, and Heðinn Valdimarsson 1841-1844 Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment P J Webster, G J Holland, J A Curry, and H.-R Chang 1844-1846 I The Origin of Planetary Impactors in the Inner Solar System Robert G Strom, Renu Malhotra, Takashi Ito, Fumi Yoshida, and David A Kring 1847-1850 Parallel Patterns of Evolution in the Genomes and Transcriptomes of Humans and Chimpanzees Philipp Khaitovich, Ines Hellmann, Wolfgang Enard, Katja Nowick, Marcus Leinweber, Henriette Franz, Gunter Weiss, Michael Lachmann, and Svante Pääbo 1850-1854 Achieving Stability of Lipopolysaccharide-Induced NF- B Activation Markus W Covert, Thomas H Leung, Jahlionais E Gaston, and David Baltimore 1854-1857 Stimulus Specificity of Gene Expression Programs Determined by Temporal Control of IKK Activity Shannon L Werner, Derren Barken, and Alexander Hoffmann 1857-1861 HST2 Mediates SIR2-Independent Life-Span Extension by Calorie Restriction Dudley W Lamming, Magda Latorre-Esteves, Oliver Medvedik, Stacy N Wong, Felicia A Tsang, Chen Wang, Su-Ju Lin, and David A Sinclair 1861-1864 Structure of SARS Coronavirus Spike Receptor-Binding Domain Complexed with Receptor Fang Li, Wenhui Li, Michael Farzan, and Stephen C Harrison 1864-1868 Toward High-Resolution de Novo Structure Prediction for Small Proteins Philip Bradley, Kira M S Misura, and David Baker 1868-1871 Azathioprine and UVA Light Generate Mutagenic Oxidative DNA Damage Peter O'Donovan, Conal M Perrett, Xiaohong Zhang, Beatriz Montaner, Yao-Zhong Xu, Catherine A Harwood, Jane M McGregor, Susan L Walker, Fumio Hanaoka, and Peter Karran 1871-1874 Extensive Diversity of Ig-Superfamily Proteins in the Immune System of Insects Fiona L Watson, Roland Püttmann-Holgado, Franziska Thomas, David L Lamar, Michael Hughes, Masahiro Kondo, Vivienne I Rebel, and Dietmar Schmucker 1874-1878 COMMENTARY Editorial Climate Equity for All Chris Huntingford and John Gash 1789 Letters A Strongly Held, But Wrong Conviction Richard G Pearson ; Early Uses of the Ivory-Billed Woodpecker Alex Barker ; Are Polar Bears Threatened? Øystein Wiig ; Using Words Carefully William H Danforth and William B Neaves ; The Slide of Education Leonid Teytelman ; An Archaeological Dilemma David I Owen ; Corrections and Clarifications 1814 Policy Forum CLIMATE: Enhanced: A Madisonian Approach to Climate Policy David G Victor, Joshua C House, and Sarah Joy 1820-1821 Books et al ASTRONOMY: People, Stars, and Scopes Vera Rubin 1817-1818 GEOLOGY: The Grand Question John C Schmidt 1818-1819 Books Received 1818 Perspectives STRUCTURAL BIOLOGY: Adaptation of SARS Coronavirus to Humans Kathryn V Holmes 1822-1823 CHEMISTRY: Bridging a Gap in Actinide Chemistry Carol J Burns 1823-1824 CHEMISTRY: Palladium-Catalyzed Oxidation of Organic Chemicals with O2 Shannon S Stahl 1824-1826 IMMUNOLOGY: Insects Diversify One Molecule to Serve Two Systems Louis Du Pasquier 1826-1827 NEWS News of the Week TEACHING EVOLUTION: ID Goes on Trial This Month in Pennsylvania School Case Constance Holden 1796 INTELLECTUAL PROPERTY: Court Tightens Patent Rules on Gene Tags Eli Kintisch 1797-1799 II PLANETARY SCIENCE: Beaming to Itokawa Richard A Kerr 1797 RESEARCH MISCONDUCT: China Science Foundation Takes Action Against 60 Grantees Gong Yidong 1798-1799 RUSSIAN SCIENCE: Government Offers Pay Raise, but Demands Reform Andrey Allakhverdov and Vladimir Pokrovsky 1798 PEDIATRIC MEDICINE: Europe Follows U.S in Testing Drugs for Children Xavier Bosch 1799 PLANETARY SCIENCE: Another Hint of Planetary Marauders Richard A Kerr 1800 BIOETHICS: Pellegrino to Succeed Kass on U.S Panel Constance Holden 1800 THEORETICAL PHYSICS: To Escape From Quantum Weirdness, Put the Pedal to the Metal Adrian Cho 1801 News Focus SCIENCE IN IRAN: An Islamic Science Revolution? Richard Stone 1802-1804 SCIENCE IN IRAN: Attack of the Killer Jellies Richard Stone 1805-1806 SCIENCE IN IRAN: The Sturgeon's Last Stand Richard Stone 1806 ATMOSPHERIC SCIENCE: Is Katrina a Harbinger of Still More Powerful Hurricanes? Richard A Kerr 1807 HURRICANE KATRINA: Scientists Weigh Options for Rebuilding New Orleans John Bohannon and Martin Enserink 1808-1809 HURRICANE KATRINA: Questioning the 'Dutch Solution' Martin Enserink and John Bohannon 1809 AMERICAN CHEMICAL SOCIETY MEETING: Safer Alternative Could Replace Widespread Contaminant Robert F Service 1810 AMERICAN CHEMICAL SOCIETY MEETING: New Techniques Aim to Thwart Terrorists Yudhijit Bhattacharjee 1810-1811 AMERICAN CHEMICAL SOCIETY MEETING: New Routes Toward Practical Hydrogen? Robert F Service 1811 Products New Products 1879 NetWatch DATABASE: To Know the Worm * COMMUNITY SITE: Focus on a Killer * RESOURCES: Breaking the Patent Barrier * RESOURCES: Making Light Coherent * DATABASE: Eating Pollution 1795 ScienceScope Audit Slams French Research * U.S to Bar Caviar * EPA Revises Pesticide Human Testing Rules * Hall In * Dale Too * And Klausner Out 1799 Random Samples Egypt in China * Crème de la Crème * A Choir of Wrens * Renewables in the Doldrums * Survivors * Politics * Awards * They Said It 1812 III EDITORIAL Climate Equity for All CREDIT: FINBARR O'REILLY/REUTERS R ecent natural catastrophes have catapulted climate into the headlines again As we witness the devastation wreaked by Hurricane Katrina, we are also reminded of numerous floods, droughts, and storms seen across the world in recent years Are these linked to climate change? Questions about climate change, its global effects, and whether and how we can tackle this issue can no longer be avoided Fortunately, this summer at the G8 Summit in Scotland, the leaders of the world’s major industrialized nations agreed on the need to reduce carbon emissions; and although there is argument about the mechanism and timing, the case for moving to a low-carbon economy is essentially won But we are faced with a rapidly changing global economy As developing countries industrialize—China and India in Asia and Brazil and Mexico in Latin America—greenhouse gas–related climate stresses are expected to increase At the same time, the environments, economies, and societies of the least-developed countries, such as those in Africa, are the most vulnerable to climate change because their ability to adapt is poor Reaching international agreement on actions to minimize the dangerous impacts of climate change requires not only negotiations among developed nations but dialogue with the developing world How we involve these developing countries in the ongoing climate change discussions, and what information is needed to inform both developing-country policies and international decisions? Local scientists could help formulate developing-country perspectives on climate change by conducting regional climate model experiments These are essentially high-resolution weather forecast models that are used to calculate the environmental impacts of predicted changed weather patterns Only when there are estimates of the economic and social impacts of changes in flood and drought frequency can possible increases in global mean temperature be translated into estimates of changes in food security and livelihoods Scientists in the developing countries concerned are best placed to undertake these detailed local analyses This work would also provide incentives to governments to maintain the long-term climate data sets that are needed for verification of climate simulations at the present levels of greenhouse gas concentrations Technologies to run modeling experiments are now being made available to scientists in developing countries But this initial technical capacity is of little use without the human scientific capacity to design and interpret the experiments Creating this expertise is a long process that, for each individual, requires continual personal development in a vibrant research environment There is strong argument for concentrating scientists at centers of excellence in the developing world When Carlos Nobre directed the Brazilian Center for Weather Forecasting and Climate Research in the 1990s, he initiated collaborations with experts in the United Kingdom and United States, building a critical mass of local expertise As a result, Brazil now includes climate change in its long-term planning for economic and land use development Earlier this year, speakers at a Royal Society meeting in London indicated that climate change is likely to increase the frequency of crop failure in Africa Other research presented this month at the British Association’s Festival of Science in Dublin warned that an extra 50 million people will be at risk of hunger by 2050, and the majority of these will be in Africa This alarming forecast begs for an Africa-based research program to investigate the possible impacts of regional climate change This need to strengthen climate change research in the developing world can be filled by establishing regional centers of excellence in developing countries and arranging training, staff exchanges, and shared research projects with developed nations The Global Environment Facility, which provides grants to developing countries for projects that benefit the environment, has a mandate to address the issue of climate change It is well placed to fund this initiative by either financing new institutions or strengthening and expanding existing organizations The African Centre of Meteorological Application for Development, a pan-African center located in Niger, is one clear candidate for this role Developing countries need to become more engaged and empowered in the international negotiations on managing global climate change This should be done quickly if we are to outrun the pace of that change Chris Huntingford and John Gash Chris Huntingford and John Gash are at the Centre for Ecology and Hydrology, Wallingford, UK 10.1126/science.1115898 www.sciencemag.org SCIENCE VOL 309 Published by AAAS 16 SEPTEMBER 2005 1789 THIS WEEK IN edited by Stella Hurtley and Phil Szuromi Klotho for Eternal Youth? A defect in Klotho gene expression in mice leads to a syndrome resembling aging Kurosu et al (p 1829, published online 25 August 2005; see the 26 August news story by Couzin) now find that Klotho overexpression extends life span in mice Klotho protein functions as a circulating hormone that binds to a cellsurface receptor and suppresses insulin and insulin-like growth factor–1 (IGF-1) signaling in an evolutionarily conserved mechanism for extending life span in worms, flies, and mice Furthermore, perturbing insulin/IGF-1 signaling slows aging in Klothodeficient mice Thus, it appears that Klotho protein may function as an antiaging hormone of Dscam, a single gene locus in insects, that has the potential to generate an exceptional level of protein diversity Originally identified as a neuronal receptor, splice products of this gene were also found in various immune tissues of Drosophila Functional studies suggest that some isotypes of Dscam could assist in the phagocytosis of bacteria, pointing to a direct and adaptable form of insect immunity Rings of Uranium Right After the Burst Apart from the Big Bang, gamma-ray bursts are the most powerful explosions in the universe and are thought to be massive stars collapsing to form black holes Such events are followed by an extended afterglow over a range of wavelengths from x-rays down to radio frequencies In the past, the afterglows were only detected several hours after the event, which resulted in missed opportunities to study this important phase of the burst Burrows et al (p 1833, published online 18 August 2005) report their detection of energetic x-ray flares in the afterglows of recent gamma-ray bursts with the Swift x-ray telescope The flares appear to be evidence of strong shock waves and extended activity in the central region of the burst CREDITS (TOP TO BOTTOM): NASA; BRINGA ET AL Stronger Under Pressure Blow Me Down It has been suggested that global warming could lead to an increase in the general level of storminess Evidence t h a t s u c h a n e f fe c t i s occurring has been elusive, however, and the links between increasing atmospheric and sea surface temperatures and hurricane activity have been debated Webster et al (p 1844; see news story by Kerr) examine the frequency and strength of tropical storms and hurricanes worldwide during the past 35 years Although there has not been an increase in the number or frequency of events, the proportion of hurricanes reaching the most energetic categories increased significantly, particularly in the Pacific and Indian Oceans For certain applications, materials need to be designed to sustain extreme shocks, as might be experienced, for example, at national ignition facilities; some nanocrystalline materials are showing promise Bringa et al (p 1838) report molecular dynamics simulations on nanocrystalline copper subjected to shock loading At high pressures, the active deformation mechanisms change from those that are thermally activated to those that are pressure mediated The results show that the copper strengthens because grain boundary sliding is suppressed by the pressure Experiments on nanocrystalline nickel confirm the behavior seen in the simulations Adaptive Immunity in Insects? Refined and complex genetic mechanisms generate huge levels of diversity in the B cell and T cell receptors of the adaptive immune system, but this diversity generation has been thought to be restricted to some higher vertebrates Watson et al (p 1874, published online 18 August 2005; see the Perspective by Du Pasquier) now describe a mechanism of alternative splicing www.sciencemag.org SCIENCE The actinide elements are well known for their nuclear instability, which leads to radioactivity and atomic energy applications However, they also engage in unusual c hemical bonding , resulting from their occupied f-orbitals and the relativistic effects of their high nuclear c harge, allowing unusual compounds to be formed and studied Evans et al (p 1835; see the Perspective by Burns) have isolated and characterized a ring of eight uranium atoms connected through alternating nitride and azide (N 3) groups Prepared by mixing an organo-uranium precursor with sodium azide in solution, the compound sheds light o n molecular uraniumnitride bonding and also models the electronics of extended lattice uranium nitride materials Connecting Craters The record of impact cratering observed on the Moon and Mars, calibrated with age determinations from Apollo samples, is the primary means for dating surfaces on the terrestrial planets Strom et al (p 1847; see news story by Kerr) have reexamined the distribution of sizes of craters, inferred the sizes of causative asteroids, and show that an older population of craters, before about 3.8 billion years ago, has the same distribution as observed asteroids in the main asteroid belt Younger craters seem to be caused by near-Earth asteroids These data imply that a process early in the history of the solar system, perhaps outward migration of the giant planets, ejected asteroids from the main belt, but that this process ceased about 3.8 billion years ago CONTINUED ON PAGE 1787 VOL 309 Published by AAAS 16 SEPTEMBER 2005 1785 CONTINUED FROM 1785 THIS WEEK IN Evolving Sequence and Expression An analysis of the evolution of both gene sequences and expression patterns in humans and chimpanzees by Khaitovich et al (p 1850, published online September 2005; see the September Editorial by Jolly, the Perspectives by Hauser and by McConkey and Varki, and the news story by Culotta) show that in the brain, heart, liver, kidneys, and testes, the general patterns of evolution conform to a neutral theory Similar patterns of selection were seen for protein sequence and gene expression Genes that are expressed in more tissues have diverged less between species than genes expressed in fewer tissues, which suggests neutral evolution with negative selections, but genes on the X chromosome that are expressed in testes showed evidence of positive selection Surprisingly, genes expressed in the brain have changed more on the human lineage than on the chimpanzee lineage, not only in terms of gene expression but also in terms of amino acid sequences Protein Sequence Structure Prediction It has long been known that the amino acid sequence of a protein defines its structure; however, the prediction of structure from sequence remains a challenge Now Bradley et al (p 1868) have achieved highresolution structure prediction (