Table of contents
Volume 461 Number 7260 pp11-134
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Editorials
Dangerous nuclear whispers p11
Voices within the Obama administration threaten to undermine non-proliferation efforts. They should be ignored.
doi:10.1038/461011a
Cash costs p11
Massive funding for Pakistan's ailing universities holds many lessons for other developing nations.
doi:10.1038/461011b
US visa nightmares p12
Barriers faced by foreign scientists seeking entry to the United States do more harm than good.
doi:10.1038/461012a
Research Highlights
Microscopy: Seeing the honeycomb p14
doi:10.1038/461014a
Exoplanets: Explaining the eccentricities p14
doi:10.1038/461014b
Biology: A colourful past p14
doi:10.1038/461014c
Immunology: Killer fat p14
doi:10.1038/461014d
Pain: Deep, deep in your head p14
doi:10.1038/461014e
Chemistry: Bacterial factories p14
doi:10.1038/461014f
Cancer biology: Cilia's dual role p15
doi:10.1038/461015a
Genetics: Y-rated p15
doi:10.1038/461015b
Microbiology: Resistance is futile p15
doi:10.1038/461015c
Food chemistry: Bee-devilled by corn syrup p15
doi:10.1038/461015d
News
News briefing: 3 September 2009 p16
The week in science.
doi:10.1038/461016a
Climate-control plans scrutinized p19
The Royal Society reviews options for fighting global warming with geoengineering.
Geoff Brumfiel
doi:10.1038/461019a
Pandemic flu: from the front lines p20
As the novel H1N1 pandemic flu virus infects people worldwide, researchers in some of the affected countries describe in their own words the scientific and public-health challenges they face.
doi:10.1038/461020a
Keeping genes out of terrorists' hands p22
Gene-synthesis industry at odds over how to screen DNA orders.
Erika Check Hayden
doi:10.1038/461022a
Stem-cell projects falter p23
Ailing economy leaves California struggling to build research labs.
Rex Dalton
doi:10.1038/461023a
Cost of climate change underestimated p24
Framework convention figure overlooks key expenses.
Anjali Nayar
doi:10.1038/461024a
Column
Party of OneBudget instructions p25
US science agencies may need to prove they are solving national problems. David Goldston explains.
David Goldston
doi:10.1038/461025a
News Features
GM crops: Battlefield p27
Papers suggesting that biotech crops might harm the environment attract a hail of abuse from other scientists. Emily Waltz asks if the critics fight fair.
doi:10.1038/461027a
Arctic ecology: Tundra's burning p34
Lightning and fires on the Arctic tundra seem to be on the rise. Jane Qiu meets the researchers learning from the scorched earth in Alaska.
doi:10.1038/461034a
Correspondence
Conservation: a small price for long-term economic well-being p37
Boris M. Hillmann & Jan Barkmann
doi:10.1038/461037a
Conservation: the world's religions can help p37
Shonil Bhagwat & Martin Palmer
doi:10.1038/461037b
Defining numbers in terms of their divisors p37
D. Speijer
doi:10.1038/461037c
Opinion
Pakistan's reform experiment p38
In 2002, Pakistan began an ambitious overhaul of its higher-education system. The successes and failures of the experience hold lessons for other countries, say Athar Osama and co-authors.
Athar Osama, Adil Najam, Shamsh Kassim-Lakha, Syed Zulfiqar Gilani & Christopher King
doi:10.1038/461038a
Books and Arts
Like minds can be small minds p40
An adviser to US President Barack Obama argues that people's tendency to seek out those with similar views can entrench extreme opinions. But many other forces can fuel outlandish beliefs, says Herbert Gintis.
Herbert Gintis reviews Going to Extremes: How Like Minds Unite and Divide by Cass R. Sunstein
doi:10.1038/461040a
Society need not be selfish p41
Michael Tomasello reviews The Age of Empathy: Nature's Lessons for a Kinder Society by Frans de Waal
doi:10.1038/461041a
Pop artist displays primitive instincts p42
A retrospective of Todd Schorr's huge oil-painted comic-book visions features his garish image of a hunter-gatherer. Is it a deliberate allegory of consumer culture, asks Martin Kemp?
Martin Kemp reviews Todd Schorr: American Surreal
doi:10.1038/461042a
News and Views
Astrophysics: Hidden chaos in cosmic order p43
"Galaxies, like elephants, have long memories," says an influential article from the 1980s. Tapping into these memories has revealed some surprising facts about the history of our neighbouring Andromeda galaxy.
Nickolay Y. Gnedin
doi:10.1038/461043a
See also: Editor's summary
Cancer: The fat and the furious p44
Evidence linking metabolic alterations to cancer progression is accumulating. It seems that cancer cells must sustain their energy production and remain well fed to survive detachment from their normal habitat.
Eyal Gottlieb
doi:10.1038/461044a
See also: Editor's summary
Materials science: Pulsating vesicles p45
During her travels through Wonderland, Alice finds several ways of growing and shrinking in size. A polymeric vesicle plays the same trick in response to pH, in a process that might one day be useful for drug delivery.
Jan C. M. van Hest
doi:10.1038/461045a
Structural biology: A channel with a twist p47
Mechanosensitive channels release tension in cell membranes by opening 'pressure relief' pores. The structure of a partially open channel suggests a gating mechanism and delivers an unexpected architectural twist.
Valeria Vásquez & Eduardo Perozo
doi:10.1038/461047a
See also: Editor's summary
50 & 100 years ago p48
doi:10.1038/461048a
Nitrogen cycle: Oceans apart p49
Reactive nitrogen is lost from the oceans as dinitrogen — N2 — produced by microbial metabolism. The latest twist in an ongoing story is that different pathways dominate in two of the oceanic regions concerned.
Maren Voss & Joseph P. Montoya
doi:10.1038/461049a
See also: Editor's summary
Neuroscience: Persistent feedback p50
How does the brain remember the consequences of our actions? Persistent activity in the prefrontal cortex and basal ganglia may be crucial for learning correct actions through experience.
Hyojung Seo & Daeyeol Lee
doi:10.1038/461050a
Correction p51
doi:10.1038/461051a
Review
Early-warning signals for critical transitions p53
Marten Scheffer, Jordi Bascompte, William A. Brock, Victor Brovkin, Stephen R. Carpenter, Vasilis Dakos, Hermann Held, Egbert H. van Nes, Max Rietkerk & George Sugihara
doi:10.1038/nature08227
First paragraph | Full Text | PDF (1,015K)
See also: Editor's summary
Brief Communications Arising
Scaling of BMP gradients in Xenopus embryos pE1
Paul Francois, Alin Vonica, Ali H. Brivanlou & Eric D. Siggia
doi:10.1038/nature08305
First paragraph | Full Text | PDF (253K)
Reply to Francois et al. pE2
Danny Ben-Zvi, Ben-Zion Shilo, Abraham Fainsod & Naama Barkai
doi:10.1038/nature08306
First paragraph | Full Text | PDF (253K)
Article
Structures of the tRNA export factor in the nuclear and cytosolic states p60
After transcription and processing, transfer RNAs must be exported from the nucleus to the cytoplasm, where translation occurs. This process is mediated by a dedicated nucleo-cytoplasmic transport factor called Xpot. Here, the structure of Schizosaccharomyces pombe Xpot is reported, unbound and in complex with both tRNA and another factor required for transport, RanGTP.
Atlanta G. Cook, Noemi Fukuhara, Martin Jinek & Elena Conti
doi:10.1038/nature08394
Abstract | Full Text | PDF (1,390K) | Supplementary information
See also: Editor's summary
Letters
The remnants of galaxy formation from a panoramic survey of the region around M31 p66
In hierarchical cosmological models, galaxies grow in mass through the continual accretion of smaller ones. The tidal disruption of these systems is expected to result in loosely bound and distant stars surrounding the galaxy. A panoramic survey of the Andromeda galaxy (M31) now reveals stars and coherent structures that are almost certainly remnants of dwarf galaxies destroyed by the tidal field of M31.
Alan W. McConnachie, Michael J. Irwin, Rodrigo A. Ibata, John Dubinski, Lawrence M. Widrow, Nicolas F. Martin, Patrick Côté, Aaron L. Dotter, Julio F. Navarro, Annette M. N. Ferguson, Thomas H. Puzia, Geraint F. Lewis, Arif Babul, Pauline Barmby, Olivier Bienaymé, Scott C. Chapman, Robert Cockcroft, Michelle L. M. Collins, Mark A. Fardal, William E. Harris, Avon Huxor, A. Dougal Mackey, Jorge Peñarrubia, R. Michael Rich, Harvey B. Richer, Arnaud Siebert, Nial Tanvir, David Valls-Gabaud & Kimberly A. Venn
doi:10.1038/nature08327
First paragraph | Full Text | PDF (450K) | Supplementary information
See also: Editor's summary | News and Views by Gnedin
Laser cooling by collisional redistribution of radiation p70
Collisional redistribution of radiation has been proposed as a cooling mechanism for atomic two-level systems. Here, a proof-of-principle demonstration is reported in which a relative cooling of 66 K is achieved in an ultradense vapour of rubidium atoms and argon buffer gas. This technique may facilitate fundamental studies of supercooling and have applications in optical refrigeration.
Ulrich Vogl & Martin Weitz
doi:10.1038/nature08203
First paragraph | Full Text | PDF (366K)
See also: Editor's summary
From molecular to macroscopic via the rational design of a self-assembled 3D DNA crystal p74
Although we live in a macroscopic three-dimensional (3D) world, our best description of the structure of matter is at the atomic and molecular scale. Reconciling these two scales with atomic precision requires high spatial control of the 3D structure of matter, with the simplest practical route to achieving this being to form a crystalline arrangement by self-assembly. Here, the crystal structure of a designed, self-assembled 3D crystal based on the DNA tensegrity triangle is reported.
Jianping Zheng, Jens J. Birktoft, Yi Chen, Tong Wang, Ruojie Sha, Pamela E. Constantinou, Stephan L. Ginell, Chengde Mao & Nadrian C. Seeman
doi:10.1038/nature08274
PDB code
3D view
First paragraph | Full Text | PDF (888K) | Supplementary information
See also: Editor's summary
Denitrification as the dominant nitrogen loss process in the Arabian Sea p78
Fixed nitrogen availability limits primary production in over half of the world's oceans. Oceanic oxygen minimum zones (OMZs) are responsible for about 35% of oceanic dinitrogen gas (N2) production and up to half of that occurs in the Arabian Sea. It has recently been argued that anaerobic ammonia oxidation (anammox) alone is responsible for fixed nitrogen loss in the OMZs; however, here it is shown that denitrification rather than anammox dominates the N2 loss term in the Arabian Sea.
B. B. Ward, A. H. Devol, J. J. Rich, B. X. Chang, S. E. Bulow, Hema Naik, Anil Pratihary & A. Jayakumar
doi:10.1038/nature08276
First paragraph | Full Text | PDF (346K) | Supplementary information
See also: Editor's summary | News and Views by Voss & Montoya
The oldest hand-axes in Europe p82
A key development in the history of technology was the transition to hand-axes and bifacial chopping tools during the Early Pleistocene (about 1.5 million years ago) in Africa. Puzzlingly, the earliest records in Europe of hand-axes lag behind this date by a million years, at around 0.5 million years ago. Here, palaeomagnetic analysis of two sites in southeastern Spain where hand-axes have been found yields revised dates of up to 0.9 million years ago, significantly closing the time gap.
Gary R. Scott & Luis Gibert
doi:10.1038/nature08214
First paragraph | Full Text | PDF (450K) | Supplementary information
See also: Editor's summary
iPS cells produce viable mice through tetraploid complementation p86
Induced pluripotent stem (iPS) cells were first created by forced expression of four transcription factors in mouse fibroblasts, a technique that has since been widely used to generate embryonic stem (ES)-cell-like pluripotent cells from a variety of cell types in other species. The generation of several iPS cell lines in mice that are capable of generating viable, fertile live-born progeny by tetraploid complementation — a technique where chimaeric mice are generated using injected pluripotent cells — is now reported.
Xiao-yang Zhao, Wei Li, Zhuo Lv, Lei Liu, Man Tong, Tang Hai, Jie Hao, Chang-long Guo, Qing-wen Ma, Liu Wang, Fanyi Zeng & Qi Zhou
doi:10.1038/nature08267
First paragraph | Full Text | PDF (871K) | Supplementary information
See also: Editor's summary
Adult mice generated from induced pluripotent stem cells p91
Differentiated cells can be reprogrammed into induced pluripotent stem (iPS) cells through the transient overexpression of a small number of transcription factors. These iPS cells resemble embryonic stem (ES) cells but, until now, they had not passed the most stringent test of pluripotency by generating full-term or adult mice in tetraploid complementation assays. Here, fertile adult mice derived entirely from iPS cells are reported.
Michael J. Boland, Jennifer L. Hazen, Kristopher L. Nazor, Alberto R. Rodriguez, Wesley Gifford, Greg Martin, Sergey Kupriyanov & Kristin K. Baldwin
doi:10.1038/nature08310
First paragraph | Full Text | PDF (772K) | Supplementary information
See also: Editor's summary
Reptilian heart development and the molecular basis of cardiac chamber evolution p95
The hearts of birds, mammals and crocodiles have two ventricles serving separate pulmonary and systemic circulations, whereas the hearts of amphibians have only one ventricle. In most reptiles, however, the situation is unclear, which is of interest in the context of the evolution of cardiac septation. Here, gene expression in the developing ventricles of two reptiles is analysed; the results suggest a role for the T-box transcription factor Tbx5.
Kazuko Koshiba-Takeuchi, Alessandro D. Mori, Bogac L. Kaynak, Judith Cebra-Thomas, Tatyana Sukonnik, Romain O. Georges, Stephany Latham, Laural Beck, R. Mark Henkelman, Brian L. Black, Eric N. Olson, Juli Wade, Jun K. Takeuchi, Mona Nemer, Scott F. Gilbert & Benoit G. Bruneau
doi:10.1038/nature08324
First paragraph | Full Text | PDF (1,405K) | Supplementary information
See also: Editor's summary
Coordination of Rho GTPase activities during cell protrusion p99
The Rho GTPase family is involved in the control of cytoskeleton dynamics, but the spatiotemporal coordination of each element (Rac1, RhoA and Cdc42) remains unknown. Here, GTPase coordination in mouse embryonic fibroblasts is examined both through simultaneous visualization of two GTPase biosensors and using a computational approach.
Matthias Machacek, Louis Hodgson, Christopher Welch, Hunter Elliott, Olivier Pertz, Perihan Nalbant, Amy Abell, Gary L. Johnson, Klaus M. Hahn & Gaudenz Danuser
doi:10.1038/nature08242
First paragraph | Full Text | PDF (879K) | Supplementary information
See also: Editor's summary
A genetically encoded photoactivatable Rac controls the motility of living cells p104
The precise spatiotemporal dynamics of protein activity remain poorly understood, yet they can be critical in determining cell behaviour. A genetically encoded, photoactivatable version of the protein Rac1, a key GTPase regulating actin cytoskeletal dynamics, has now been produced; this approach enables the manipulation of the activity of Rac1 at precise times and places within a living cell, thus controlling motility.
Yi I. Wu, Daniel Frey, Oana I. Lungu, Angelika Jaehrig, Ilme Schlichting, Brian Kuhlman & Klaus M. Hahn
doi:10.1038/nature08241
First paragraph | Full Text | PDF (947K) | Supplementary information
See also: Editor's summary
Antioxidant and oncogene rescue of metabolic defects caused by loss of matrix attachment p109
Normal mammary epithelial cells require attachment to the extracellular matrix (ECM) for survival, but in breast cancers tumour cells acquire the ability to survive outside their natural ECM niches. Here it is found that cell detachment induces metabolic defects which can be rescued by both the expression of the oncogene ERBB2 and — unexpectedly — by antioxidants, which, in this context, help promote cancer cell survival and proliferation.
Zachary T. Schafer, Alexandra R. Grassian, Loling Song, Zhenyang Jiang, Zachary Gerhart-Hines, Hanna Y. Irie, Sizhen Gao, Pere Puigserver & Joan S. Brugge
doi:10.1038/nature08268
First paragraph | Full Text | PDF (558K) | Supplementary information
See also: Editor's summary | News and Views by Gottlieb
Direct activation of protein kinases by unanchored polyubiquitin chains p114
The ubiquitin ligase TRAF6 is essential for the activation of NF-
B and MAP kinases in several signalling pathways important for a range of cellular processes including immune function. TRAF6 functions together with a ubiquitin-conjugating enzyme complex to activate the TAK1 kinase complex downstream, which in turn leads to the activation of NF-B. Here, by reconstituting TAK1 activation in vitro, free Lys 63 polyubiquitin chains are shown to activate TAK1 directly.
Zong-Ping Xia, Lijun Sun, Xiang Chen, Gabriel Pineda, Xiaomo Jiang, Anirban Adhikari, Wenwen Zeng & Zhijian J. Chen
doi:10.1038/nature08247
First paragraph | Full Text | PDF (663K) | Supplementary information
See also: Editor's summary
Structure of a tetrameric MscL in an expanded intermediate state p120
Mechanosensitive channels protect bacteria from osmotic shock by allowing ions to flow across the membrane in response to changes in membrane tension. MscL is one such channel with a large conductance. Although understanding of its closed and open states has been increasing, little is known about the structures of the important intermediate states. Here, the 3.8 Å crystal structure of MscL in what is probably a non-conductive, partially expanded intermediate state, is presented.
Zhenfeng Liu, Chris S. Gandhi & Douglas C. Rees
doi:10.1038/nature08277
PDB code
3D view
First paragraph | Full Text | PDF (1,175K) | Supplementary information
See also: Editor's summary | News and Views by Vásquez & Perozo
Direct observation of the binding state of the kinesin head to the microtubule p125
Kinesin is a dimeric motor protein which is known to move along microtubule filaments by using its twin motor domains (heads) to carry out an asymmetric, 'hand-over-hand' walk. However, the extent of individual head interactions with the microtubule has remained controversial. Here, a single-molecule assay is developed that can directly report head binding and unbinding during kinesin movement.
Nicholas R. Guydosh & Steven M. Block
doi:10.1038/nature08259
First paragraph | Full Text | PDF (911K) | Supplementary information
See also: Editor's summary
Naturejobs
Careers and RecruitmentWaiting game p131
Visa problems continue to frustrate scientists seeking entry to the United States. Karen Kaplan investigates the roadblocks.
Karen Kaplan
doi:10.1038/nj7260-131a
Futures
Fine-tuning the Universe p134
Touched by the hand of God.
Merrie Haskell
doi:10.1038/461134a
