Tạp chí khoa học số 2006-03-03

TeAM YYeP G Digitally signed by TeAM YYePG DN: cn=TeAM YYePG, c=US, o=TeAM YYePG, ou=TeAM YYePG, email=yyepg@ms n.com Date: 2006.03.07 11:11:38 +08'00' 3 March 2006 | $10 YYePG Proudly Presents,Thx for Support YYePG Proudly Presents,Thx for Support YYePG Proudly Presents,Thx for Support GE Healthcare To 100,000 scientists worldwide, the name ÄKTA ™ has always meant outstanding protein purification, and now it’s brought to you by GE Healthcare. With the ability to purify virtually 100% of all biomolecules, the ÄKTAdesign ™ platform can handle the toughest of challenges. Whatever the scale, from laboratory, to process development and manufacturing, there’s an ÄKTAdesign system to meet every need. All systems in the ÄKTAdesign family work with the intelligent UNICORN ™ software, which makes it easy to control every stage of your purification processes. Accurate, reproducible results just take a little pure imagination. Visit www.amershambiosciences.com/aktadesign Why do 100,000 scientists trust GE Healthcare for all their protein purification needs? Here’s Ä clue. © 2005 General Electric Company - All rights reserved. Amersham Biosciences AB, a General Electric company going to market as GE Healthcare. GE15-05 YYePG Proudly Presents,Thx for Support www.sciencemag.org SCIENCE VOL 311 3 MARCH 2006 1201 CONTENTS CONTENTS continued >> NEWS OF THE WEEK As H5N1 Keeps Spreading, a Call to Release 1224 More Data Evidence Points to Migratory Birds in H5N1 Spread 1225 DOE Hits Potholes on the Road to Systems Biology 1226 Canadian Editors Fired in Row With Association 1226 Despite a Chilly Reception, the ‘European MIT’ 1227 Advances SCIENCESCOPE 1227 NSF Presents the Wide World of Science 1228 Indian Chemist Receives a Visa and an Apology 1229 Protesters March to a Different Drummer 1229 NEWS FOCUS The Lost World of the Kihansi Toad 1230 Great Balls of Fat 1232 Getting Women Scientists Back on the Career Track 1235 in Japan A $214 Billion Plan of Action A Passion for Teaching Leads to Engineering Change 1237 in Schools DEPARTMENTS 1207 Science Online 1209 This Week in Science 1214 Editors’ Choice 1218 Contact Science 1221 NetWatch 1223 Random Samples 1239 Newsmakers 1304 New Products 1305 Science Careers COVER The enzymes that catalyze fatty acid formation are large protein complexes with multiple active sites. The architecture of the mammalian multienzyme (catalytic domains in various colors) is quite different from that of the fungal fatty acid synthase (in gray). Nonetheless, they catalyze the same conserved reaction pathway. See pages 1258 and 1263. Image: S. Jenni and T. Maier EDITORIAL 1213 The Mailbag by Donald Kennedy 1230 LETTERS Crucial Choices for the Nascent ERC Initiative for 1240 Science in Europe Objectivity in Science K. R. Gordon Influenza Mutation from Equine to Canine M. von Grotthuss and L. Rychlewski Response P. C. Crawford et al. CORRECTIONS AND CLARIFICATIONS 1242 BOOKS ET AL. René Dubos, Friend of the Good Earth 1243 Microbiologist, Medical Scientist, Environmentalist C. L. Moberg, reviewed by J. Strick Civilized Life in the Universe 1244 Scientists on Intelligent Extraterrestrials G. Basalla, reviewed by M. Shermer POLICY FORUM A National Tuberculosis Archive 1245 D. Gessler et al. A Portfolio Model of Drug Development 1246 for Tuberculosis S. W. Glickman et al. PERSPECTIVES Who Are More Helpful, Humans or Chimpanzees? 1248 J. B. Silk >> Reports pp. 1297 and 1301 An Example of Preclassic Mayan Writing? 1249 S. D. Houston >> Report p. 1281 Creep and Flow on the Icy Moons 1250 of the Outer Planets P. R. Sammonds >> Report p. 1267 Architectural Options for a Fatty Acid Synthase 1251 S. Smith >> Research Articles pp. 1258 and 1263 Volume 311, Issue 5765 1245 YYePG Proudly Presents,Thx for Support Success with proteins — made possible by QIAGEN’s expertise! QIAGEN’s experience in sample preparation technology will help you rise to the challenge of working with proteins. QIAGEN provides easy-to-use, integrated solutions to help you succeed with: ■ Expression ■ Purification ■ Detection ■ Assay ■ Crystallization ■ MALDI sample prep ■ Proteomics ■ Automation For up-to-date trademarks and disclaimers, see www.qiagen.com . PROTTAG0106S1WW © 2006 QIAGEN, all rights reserved. Systems Biology — Proteins and Proteomics Standardized solutions for proteins WWW.QIAGEN.COM Find a standardized solution for your protein challenge at www.qiagen.com/protein ! E. coli gyrase A C-terminal domain crystals. Courtesy of Alex Ruthenburg from Prof. Verdine’s laboratory, Harvard University, Boston, USA. Ni-NTA matrices offer highly specific and selective binding of 6xHis-tagged proteins YYePG Proudly Presents,Thx for Support YYePG Proudly Presents,Thx for Support YYePG Proudly Presents,Thx for Support www.sciencemag.org SCIENCE VOL 311 3 MARCH 2006 1203 CONTENTS continued >> REVIEW NEUROSCIENCE Auxiliary Subunits Assist AMPA-Type 1253 Glutamate Receptors R. A. Nicoll, S. Tomita, D. S. Bredt BREVIA MEDICINE Cellular Senescence in Aging Primates 1257 U. Herbig, M. Ferreira, L. Condel, D. Carey, J. M. Sedivy As baboons age, cells that have become irreversibly senescent accumulate in various tissues, likely contributing to the aging of the whole animal. RESEARCH ARTICLES STRUCTURAL BIOLOGY Architecture of Mammalian Fatty Acid Synthase 1258 at 4.5 Å Resolution T. Maier, S. Jenni, N. Ban Architecture of a Fungal Fatty Acid Synthase 1263 at 5 Å Resolution S. Jenni, M. Leibundgut, T. Maier, N. Ban The large multiprotein complexes that synthesize fatty acids in mammals and fungi have radically different architectures. >> Perspective p. 1251 REPORTS PLANETARY SCIENCE Grain Size–Sensitive Creep in Ice II 1267 T. Kubo, W. B. Durham, L. A. Stern, S. H. Kirby Experiments show that grain size influences the deformation speed of ice under high pressure, modifying models of the evolution and internal dynamics of icy moons. >> Perspective p. 1250 APPLIED PHYSICS Giant Electrocaloric Effect in Thin Film 1270 PbZr 0.95 Ti 0.05 O 3 A. S. Mischenko et al. Application of an electric field to a thin lead zirconium titanium oxide produces a surprisingly large drop in its temperature, suggesting a potential refrigeration technology. MATERIALS SCIENCE Surface Self-Organization Caused by 1272 Dislocation Networks K. Thürmer, R. Q. Hwang, N. C. Bartelt The organization of silver ions on a ruthenium surface depends on dislocations below the surface and not on strain or surface tension as had been thought. CONTENTS SCIENCE EXPRESS www.sciencexpress.org CLIMATE CHANGE Changes in Surface Water Supply Across Africa with Predicted Climate Change M. de Wit and J. Stankiewicz Simulations of future precipitation imply that reduced stream flow will further restrict water availability across much of sub-Saharan Africa over the next century. 10.1126/science.1119929 CLIMATE CHANGE Measurements of Time-Variable Gravity Show Mass Loss in Antarctica I. Velicogna and J. Wahr Satellite measurements of Earth’s gravity reveal that the mass of ice in Antarctica decreased from 2002 to 2005, mainly from losses in the West Antarctic Ice Sheet. 10.1126/science.1123785 CHEMISTRY Probing Proton Dynamics in Molecules on an Attosecond Time Scale S. Baker et al. Nuclear motion in H 2 and methane could be clocked less than a femtosecond after ionization by analysis of the photons released through electron-ion recombination. 10.1126/science.1123904 IMMUNOLOGY Evidence for a Functional Second Thymus in Mice G. Terszowski et al. Mice have a second thymus in the neck that contributes functional T cells to the immune system, forcing a rethinking of previous experiments that assumed a single thymus. 10.1126/science.1123497 IMMUNOLOGY Naïve and Memory CD4 + T Cell Survival Controlled by Clonal Abundance J. Hataye, J. J. Moon, A. Khoruts, C. Reilly, M. K. Jenkins Clonal subpopulations of immune T cells—each of which binds to a different antigen— are more stable if they contain smaller numbers of cells. 10.1126/science.1124228 YYePG Proudly Presents,Thx for Support . Schools DEPARTMENTS 1207 Science Online 1209 This Week in Science 1214 Editors’ Choice 1218 Contact Science 1221 NetWatch 1223 Random Samples 1239 Newsmakers 1304 New Products 1305 Science Careers COVER The. detection experiments. YYePG Proudly Presents,Thx for Support www.sciencemag.org SCIENCE VOL 311 3 MARCH 2006 1207 ONLINE SCIENCENOW www.sciencenow.org DAILY NEWS COVERAGE Knocked Off Balance by Faulty. AND www.sciencemag.org/prizes/ Call for Entries Science and Engineering’s most powerful statements are not made from words alone YYePG Proudly Presents,Thx for Support www.sciencemag.org SCIENCE