Volume 465 Issue 7295, 13 May 2010

The University of Virginia should fight a witch-hunt by the state's attorney general.

Europe's Joint Research Centre needs to find its place alongside the new chief scientific adviser.

The week in science.

Yunnan's worst drought for many years has been exacerbated by destruction of forest cover and a history of poor water management.

Appointment of new chief may trigger wider changes.

A technology that simultaneously reads a DNA sequence and its crucial modifications makes its debut.

The eruption of Mount St Helens in 1980 left an indelible mark on the field of volcanology. Janet Fang reports.

Discovery that some humans are part-Neanderthal reveals the promise of comparing genomes old and new.

Legislators opt for pragmatism over nationalism.

In February, a biologist gunned down three colleagues at the University of Alabama, Huntsville. Meredith Wadman reports how their department is trying to move past the tragedy.

The climate community must work together to create a single, clean, comprehensive and open repository of detailed temperature data, say Peter A. Stott and Peter W. Thorne.

Klaus Stöhr of Novartis argues that pre-pandemic immunization with a cocktail of likely strains could be a cheap, practical and equitable way to protect people against influenza.

Deborah M. Gordon enjoys a photographic paean to individual ants and their rarely glimpsed exploits on behalf of the collective.

Oceanographer and underwater explorer Sylvia Earle served as chief scientist of the US National Oceanic and Atmospheric Administration during 1990–92, and is a US national committee member of the Census of Marine Life, due to conclude this October. Earle advised on Disney's newly released cut of the documentary film Oceans; here she explains why films are important for raising awareness of the state of our seas.

Robots have to store lots of information in order to coordinate their actions, but how can this be done for nanometre-scale robots? One answer is to program data into the robots' environment instead.

The question of whether or not all life on Earth has an ultimate common origin is a subtle one, complicated by the phenomenon of lateral gene transfer. It has now been tackled with a formal statistical analysis.

Increased erosion associated with the rise of the world's great mountain ranges has been held to be the cause of a prolonged episode of past climate cooling. That connection is now brought into doubt.

Membrane transporter proteins switch between conformational states to move substrates across membranes. The transition between these states can now be studied using single-molecule experiments.

For many potential applications, carbon nanotubes must be chemically modified, but the reactions involved aren't easily controlled. The discovery of a reversible modification process is a step towards such control.

Genomes don't just encode protein-coding RNAs. They also give rise to various groups of RNAs that can regulate gene expression. Short RNAs that form from enhancer sequences might be one such class of regulatory RNA.

Induced pluripotent stem cells (iPSCs) are generated by the enforced expression of particular transcription factors in somatic cells. The extent to which such cells are equivalent to embryonic stem (ES) cells is an open question. Here, genetically identical mouse ES cells and iPSCs have been compared; the overall expression patterns of messenger RNAs and microRNAs are the same, with the exception of a few transcripts encoded within an imprinted gene cluster on chromosome 12qF1.

Regulatory proteins bind non-coding DNA either at promoters (near to a gene's transcription start site) or at enhancers (far away). Binding at enhancers helps to bring the transcription enzyme RNA polymerase to promoters. Here, studies of some 12,000 enhancers that respond to electrical activity in neurons show that binding to enhancers also brings the polymerase to the enhancers themselves, where it transcribes a novel class of non-coding RNAs. Enhancers may thus be more similar to promoters than hitherto appreciated.

Neurotransmitter:Na⁺ symporters (NSS) remove neurotransmitters from the synapse in a reuptake process that is driven by the Na⁺ gradient. Here, single-molecule fluorescence imaging assays have been combined with molecular dynamics simulations to probe the conformational changes that are associated with substrate binding and transport by a prokaryotic NSS homologue, LeuT. The findings are interpreted in the context of an allosteric mechanism that couples ion and substrate binding to transport.

NGC 6791 is a well studied open cluster that is so close to us that it can be imaged down to very faint luminosities. Two different ages have been proposed for this cluster, one based on the white dwarf luminosity function and one derived from its main-sequence stars. The discrepancy in age is now resolved by the finding that, as theoretically anticipated, physical separation processes occur in the core of white dwarfs.

Interactions between microscopic particles are usually described as two-body interactions, although it has been shown that higher-order multi-body interactions could give rise to new quantum phases with intriguing properties. Here, effective six-body interactions are demonstrated in a system of ultracold bosonic atoms in a three-dimensional optical lattice.

Many new functional materials and devices could be made if it were possible to rationally combine nanometre-scale particles into larger structures. An assembly line operating on the nanometre scale has now been demonstrated. It uses a DNA origami tile as a framework and track for the assembly process, three distinct DNA machines attached to the tile as programmable cargo-donating devices, and a DNA walker to generate the target product by moving along the track and collecting cargo from those devices that are switched on.

Traditional robots need to store internal representations of their goals and environment, and to coordinate sensing and the movement of components required in response. Individual molecules are limited in their ability to store complex information, but robotic behaviour can still be realized — as has now been shown with DNA walkers, which can carry out a sequence of actions such as 'start', 'follow', 'turn' and 'stop' that are programmed into the DNA landscape on which the walkers move.

Accelerated uplift and global cooling have been suggested as possible causes for a fourfold increase in global sedimentation rates, and by inference in erosion rates or weathering fluxes, during the past 5 million years. Here, proxy evidence is provided that indicates stable weathering fluxes in the late-Cenozoic era. It is proposed that processes different from an increase in denudation caused Cenozoic global cooling.

The Burgess Shales of British Columbia are famous for having yielded fossils of soft-bodied creatures from the Middle Cambrian period. Although similar faunas are now known from localities as far apart as China and Greenland, they seem to have died out before the end of the Cambrian. Or did they? Here, the discovery of a Burgess Shale-type fauna from the Ordovician period in Morocco is reported, showing that creatures of this type persisted beyond the end of the Cambrian.

It is generally assumed that life had a single origin — or, at least, that all extant life descended from a 'universal common ancestor' (UCA) — although this view has been called into question by evidence for extensive horizontal gene transfer. Here, the UCA view is framed as a formal hypothesis and tested (crucially, without assuming that genetic similarity reflects genetic kinship). The UCA view triumphs: a single origin of life is overwhelmingly more likely than any competing hypothesis.

Amyotrophic lateral sclerosis (ALS) is a disorder characterized by the degeneration of motor neurons. About 10% of cases are familial, but the mutations identified in these families account for only 20–30% of such cases. Here a new set of mutations in familial ALS is found — in the gene encoding optineurin. Given the effect of optineurin mutations on the NF-κB protein, it is suggested that inhibiting NF-κB might be useful in treating ALS.

The main reason why tumours are not controlled by the immune system is that they do not express potent tumour rejection antigens. Tumour vaccination aims to provoke a response to any antigens that are expressed. Here, a new approach is described: nonsense-mediated messenger RNA decay in tumour cells is inhibited, leading to the expression of new antigens and to significant inhibition of tumour growth in mice.

GABA_B receptors are the G-protein-coupled receptors for γ-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain. Here, functional proteomics is used to show that GABA_B receptors in the brain are complexes of GABA_B1, GABA_B2 and members of a subfamily of KCTD proteins. The KCTD proteins increase the potency of agonists and markedly alter the G-protein signalling of the receptors, suggesting that they determine the pharmacology and kinetics of the receptor response.

Spider silk proteins are remarkably soluble when stored at high concentration and yet can be converted to extremely sturdy fibres, through unknown molecular mechanisms. Here, the X-ray structure of the amino-terminal domain of a silk protein is presented, revealing how evolutionarily conserved polar surfaces might control self-assembly as the pH is lowered along the spider's silk extrusion duct. Such a mechanism might be applicable to the design of versatile fibrous materials.

Spider silk proteins are remarkably soluble when stored at high concentration and yet can be converted to extremely sturdy fibres, through unknown molecular mechanisms. Here, the structure of the evolutionarily conserved carboxy-terminal domain of a silk protein is presented. The results provide evidence that the structural state of this domain is essential for controlled switching between the storage and assembly forms of silk proteins. Such molecular switches might see application in the design of versatile fibrous materials.

Polycomb group (PcG) proteins are transcriptional repressors that modify chromatin and regulate important developmental genes. One PcG-associated, chromatin-modifying activity is an enzyme that ubiquitinates histone H2A of chromatin. Here, a fruitfly PcG complex that is associated with H2A deubiquitination, and thereby with gene repression, is identified. PcG-mediated gene silencing might thus involve a dynamic balance between ubiquitination and deubiquitination of H2A.

Hydrogen metabolism is facilitated by the activity of three hydrogenase enzymes. The catalytic core of the [FeFe]-hydrogenase (HydA), called the H-cluster, exists as a [4Fe4S] subcluster linked to a modified 2Fe subcluster. Here, Chlamydomonas reinhardtii HydA was expressed in a genetic background that did not contain the other hydrogenase biosynthetic genes. The structure of this HydA was then solved, revealing the stepwise manner by which the H-cluster is synthesized, and offering insight into how HydA might have evolved.

Leo Gross, a surface chemist at IBM Research-Zurich in Switzerland, has received the first annual Gerhard Ertl Young Investigator Award for atomic-resolution images of molecules using non-contact atomic force microscopy.

Tough economy forces scaled-down grants at Science Foundation Ireland.

University rankings seem to sway academics' opinions of institutions, says study.

Report calls for changes to US education.

Rapid technological developments have spurred big changes in the requisite genome-sequencing jobs. Kelly Rae Chi assesses the sequencing assembly line.

Early learning.