Volume 468 Issue 7322, 18 November 2010

A clumsy immigration cap could damage UK science by keeping skilled researchers out.

Tough lessons must be learned if NASA is to avoid repeating a costly accounting error.

Beware the urge to direct research too closely, says Nobel laureate Ahmed Zewail. History teaches us the value of free scientific inquisitiveness.

The week in science.

An independent review finds NASA's flagship James Webb observatory is perilously overspent.

Positive results inject life into strategy to treat heart disease.

Magnetically trapped atoms could test fundamental physics.

A comparison of funding level and output has captured attention at the US National Institutes of Health.

Pilot scheme paves way for university research to be awarded on the basis of society benefits.

National health-research centres take shape.

Biologists' collaborative data repositories come of age.

The release of climate-science e-mails last November ripped apart Phil Jones's life. He's now trying to patch it back together.

Sleep researcher Sara Mednick has straddled the line between media darling and respected scientist. But why is there still a line at all?

New forecasts suggest that coal reserves will run out faster than many believe. Energy policies relying on cheap coal have no future, say Richard Heinberg and David Fridley.

Our global economy must operate within planetary limits to promote stability, resilience and wellbeing, not rising GDP, argues Peter Victor.

Kevin Kelly argues compellingly that technology is taking on a life of its own, finds Zaheer Baber.

Emma Marris is intrigued by an optimistic vision of high–rise farms.

Josie Glausiusz enjoys a play capturing the zeal and backstabbing in the race to discover DNA's structure.

Alison Abbott visits an exhibition charting the artistic and scientific interests of painter and collector Gabriel von Max.

Mathematician, and father of fractal geometry, who described the roughness of nature.

An extension of synthetic biology to a medicinal plant involves the transfer of chlorination equipment from bacteria. This exercise adds implements to the enzymatic toolbox for generating natural products. See Letter p.461

Nuclear magnetic resonance is a versatile analytical technique, but acquiring well-resolved NMR spectra of chemical surfaces has been hard. The coming of age of a spectral enhancement method should change all that.

Mobile DNA sequences called L1 contribute to the brain's genetic heterogeneity and may affect neuron function. The protein MeCP2, which is mutated in Rett syndrome, seems to regulate the activity of these genomic elements. See Letter p.443

Quantum physics is known for its counter-intuitive principles. One such principle — that a single photon can be in as many as four places at the same time — has now been demonstrated. See Letter p.412

The use of catch data to determine indicators of biodiversity such as 'mean trophic level' does not adequately measure ecosystem changes induced by fishing. Improved ways to assess those changes are required. See Letter p.431

In roundworms, age-related decline in egg quality is regulated by specific humoral signalling pathways. If similar mechanisms operate in mammals, these findings may suggest ways to delay reproductive ageing in women.

Many naturally occurring substances have a 'handedness' that enables them to interact highly specifically with matter or light. The helical features responsible for this can now be replicated in solid, porous films. See Letter p.422

We know that dark matter constitutes 85 per cent of all the matter in the Universe, but we do not know of what it is made. Among the many dark matter candidates proposed, WIMPs (weakly interacting massive particles) occupy a special place. The moment of truth has now come for WIMPs: either we will discover them in the next five to ten years, or we will witness their inevitable decline.

When songbirds sing, neurons in premotor areas fire coordinated bursts precisely timed to the dynamics of the song. The cellular mechanism for such sequence generation is unknown. These authors make the technical breakthrough of recording intracellularly in HVC neurons in singing birds, allowing them to test models of burst generation. They found that membrane potential rapidly depolarizes 5–10 ms before burst onset, consistent with models in which HVC neurons form synaptically connected chains.

The F-box protein CORONATINE INSENSITIVE 1 (COI1) mediates jasmonate signalling by promoting hormone-dependent ubiquitylation and degradation of the JASMONATE ZIM DOMAIN (JAZ) family of transcriptional repressors. These authors elucidate the mechanism of jasmonate perception. They present structural and pharmacological data to show that the true jasmonate receptor is a complex of both COI1 and JAZ. In addition, inositol pentakisphosphate functions as a critical component of the hormone receptor complex.

DNA bases that are alkylated or deaminated are removed by DNA glycosylase repair enzymes. In structures of several other DNA glycosylases, the modified base inserts into the active site. These authors solve the structure of glycosylase AlkD, find that the modified base is extruded in an extrahelical position and propose a model for how this solvent-exposed position allows cleavage of N3- and N7-alkylated bases specifically.

Quantum networks are being developed for computation, communication and simulation. These authors demonstrate a quantum network capable of storing and reading out entanglement among multiple parties. It comprises four atomic memories connected by photonic channels, representing a significant increase in complexity in comparison with previous two-party networks.

Single-molecule magnets are molecular complexes with magnetic bistability, and recently it was shown that such a magnetic memory effect is retained for Fe₄ clusters when they are wired to a gold surface. These authors have tailored the clusters to have a preferential orientation and form a self-assembled monolayer on the surface. It then becomes possible to observe quantum tunnelling of the magnetization, which shows up as steps in the magnetic hysteresis loop.

Some beetle shells exhibit iridescence owing to the chiral organization of chitin making up the beetle's exoskeleton. Inspired by this, these authors fabricate thin glass films with helical pores introduced using a renewable cellulose template. The chiral structure allows the material, which can be free-standing, to selectively reflect light at a specific wavelength that can be tuned across the visible spectrum by altering the ratio of silica to cellulose during synthesis.

The deformation style at moderately active volcanoes — such as Eyjafjallajökull, Iceland, which underwent an explosive summit eruption earlier this year — is little understood. These authors show that deformation associated with the eruptions at Eyjafjallajökull was unusual as it did not relate to pressure changes within a single magma chamber, and infer that this behaviour might be attributed to its off-rift setting with a 'cold' subsurface structure and limited magma at shallow depth.

The health of marine ecosystems is traditionally assessed by measuring the mean trophic level (MTL) of fishery catches. These authors model catch MTL and actual ecosystem MTL, and show that the former is not a good measure of the latter. They then show that MTLs have actually been increasing in recent years, but that fisheries are still at risk of collapse because all trophic levels have been similarly affected.

In vertebrates, sex can be determined either genetically or by temperature, but the evolutionary causes of this variation remain unknown. These authors show how live-bearing lizards at different climatic extremes of their range differ in their sex-determining mechanisms, with temperature-dependent sex determination in the lowlands and genotypic sex determination at higher altitudes. Their results establish an adaptive explanation for intra-specific divergence in sex-determining systems driven by phenotypic plasticity and ecological selection.

Contact-dependent growth inhibition (CDI) through a two-component system was first described in Escherichia coli as a mechanism to inhibit growth of bacterial cells that do not possess this system. Now the widespread occurrence of CDI in bacteria and the molecular basis for some of these interactions have been elucidated. The data suggest that CDI is a common mechanism by which microbes compete with each other in the environment.

Long interspersed nuclear elements-1 (L1) retrotransposons affect gene expression and neuronal function throughout brain development. These authors show that the absence of methyl-CpG-binding protein 2, a modulator of DNA methylation implicated in several neurodevelopmental disorders, increases L1 retrotransposon activity in rodent models, with this increase in susceptibility duplicated in patients with Rett syndrome. These correlations suggest that disease-related genetic mutations may influence L1 retrotransposon activity.

Natural killer cells and cytotoxic T cells kill virus-infected and malignant cells, releasing the pore-forming protein perforin in the process. Perforin is required for the delivery of pro-apoptotic granzymes to the target cell. These authors present the crystal structure of a perforin monomer together with a cryo-electron microscopy reconstruction of the oligomeric pore. Perforin monomers within the pore are arranged with an inside-out orientation relative to the structurally homologous monomers of cholesterol-dependent cytolysins.

Many cellular and virus messenger RNAs are methylated at the 2′-O positions of the 5′ guanosine cap. The role of 2′-O methylation in virus infection has been unclear. These authors show that this form of methylation enables several unrelated viruses to evade the antiviral effects of genes stimulated by type I interferon.

Reprogramming of X-chromosome inactivation during the acquisition of pluripotency is accompanied by repression of Xist, the trigger of X-inactivation, and by upregulation of its antisense counterpart, Tsix. In undifferentiated embryonic stem cells (ESCs), key transcription factors that support pluripotency repress Xist transcription. These authors show that upregulation of Tsix in ESCs depends on a different subset of pluripotency factors. Therefore, two distinct ESC-specific complexes couple reprogramming of X-inactivation to pluripotency.

Halogen atoms have been observed in several different classes of natural product, but very few halogenated natural products have been isolated from terrestrial plants. These authors show that biosynthetic machinery responsible for chlorination events in bacteria could be introduced into the medicinal plant Catharanthus roseus. Prokaryotic halogenases function within the plant cells to generate chlorinated tryptophan, which is then used by the monoterpene indole alkaloid metabolic pathways to yield chlorinated alkaloids.

Some scientists embrace the media; others bristle. All should know how to reach out, and how their careers can benefit.

Keeping a visible record of your rejected applications can help others to deal with setbacks, says Melanie Stefan.

Information at your fingertips.