Volume 468 Issue 7323, 25 November 2010

Moves to price new pharmaceuticals sensibly shouldn't damage the industry's health.

Scientists should speak out on the environmental effects of ventures such as tar-sands mining.

Next week's climate meeting in Mexico should avoid talk of more ambitious targets, says Yvo de Boer. First, we need people to believe in green growth.

The week in science.

Those tackling the epidemic are struggling to keep pace with an escalating crisis.

Cases highlight the challenge of policing multinational trade in stem-cell treatments.

Critics say that explanation of the 2010 award in physics slights other contributions to graphene research.

A once much-touted technique faces a difficult transition to the clinic.

With nations in gridlock over emissions, UN negotiators are concentrating on side deals to revive an ailing process.

Learning how melanoma fights back may yield new therapies.

What can microbiologists who study human bowels learn from those who study the bowels of Earth?

The ancient Greeks' vision of a geometrical Universe seemed to come out of nowhere. Could their ideas have come from the internal gearing of an ancient mechanism?

As Canada exploits its oil sands ever faster, David Schindler calls for industry-independent environmental monitoring to back up better water-quality regulation.

A critical mass of female voices changes the tenor of political and corporate decisions — and should be used to galvanize climate policy, says Susan Buckingham.

The panda's plight shows how protection often vies with economic necessity, finds Jane Qiu.

Douglas Gough enjoys a wide-ranging tour of the many influences of our nearest star.

Alfred Keller's fastidious models of insects highlight his skill as an observer and a sculptor, finds Martin Kemp.

Jascha Hoffman reads about some creative research environments that led to unexpected discoveries.

A type of sugar transporter has been discovered that exports glucose from cells. In plants, these transporters are targeted by disease-causing microbes that divert sugar production for their own use. See Article p.527

A neat way of measuring the geometry of the Universe offers a new test of the standard cosmological model. It probes, among other things, the elusive dark energy thought to be driving the Universe's expansion. See Letter p.539

The timing of the dispersal of our species from Africa is a continuing and lively topic of debate. Evidence that modern humans existed in China more than 100,000 years ago is both equivocal and thought-provoking.

The size of a cell's nucleus is usually proportional to the size of the cell itself. How are the two linked? The answer lies, at least in part, in the import of one or more cytoplasmic cargoes into the nucleus.

A simple peptide that assembles into desirable nanoscale structures is a striking example of how the whole can be greater than the sum of its parts. What's more, the assembly process is controllably reversible.

Bose–Einstein condensation, which demonstrates the wave nature of material particles, now offers further illumination of wave–particle duality: it has been observed in light itself. See Letter p.545

Accurate cell division depends on proper attachment of chromosomes to the microtubule-based division apparatus. An impressive in vitro study shows how applied force plays a pivotal part in regulating such attachment. See Letter p.576

It is hoped that reactivating the tumour-suppressor protein p53 will help to combat cancer. However, fresh evidence suggests it is unlikely that all cells in a tumour will respond to such treatment. See Letters p.567 & p.572

Mouse fibroblasts expressing a small subset of transcription factors can be induced to differentiate towards specified lineages without reverting to an embryonic state. Now direct conversion of dermal fibroblasts to multipotent blood progenitors has been achieved in vitro in the human, using just one factor.

Sugar efflux transporters are essential for diverse processes such as nectar production and seed and pollen development, as well for the maintenance of blood glucose levels in animals. These authors identify and characterize a novel sugar transporter family, SWEET, and show that several Arabidopsis, rice and metazoan homologues mediate glucose transport. In addition, some of these transporters are exploited by plant pathogens for nutritional gain and virulence.

In cells, WAVE protein, a central regulator of actin dynamics during cell motility, is constitutively incorporated into WAVE regulatory complex (WRC), is normally present in an inactive state and can be activated by a number of inputs. These authors present the structure and mechanistic analysis of WRC. The combined data reveal how the WAVE protein is inhibited within the WRC complex and provide mechanisms for WRC activation at the plasma membrane.

The acceleration of the expansion of the Universe is attributed to a 'dark energy' component that opposes gravity. These authors report an analysis of the symmetry properties of distant pairs of galaxies from archival data. This allows them to determine that the Universe is flat, and by alternately fixing its spatial geometry and the dark energy equation-of-state parameter, w_X, they establish at the 68.3 per cent confidence level that −0.85 > w_X > −1.12 and 0.60 < Ω_X < 0.80, where Ω_X is the abundance of dark energy.

Masses of pulsating classical Cepheid supergiants derived from stellar pulsation theory are smaller than the masses derived from stellar evolution theory. An independent determination for a classical Cepheid in a binary system is needed to determine which is correct. These authors report the discovery of a classical Cepheid in the Large Magellanic Cloud. They determine the mass to a precision of one per cent and show that it agrees with its pulsation mass.

Bose–Einstein condensation has been observed in several physical systems, but is not predicted to occur for blackbody radiation such as photons. However, it becomes theoretically possible in the presence of thermalization processes that conserve photon number. These authors experimentally realise such conditions, observing Bose–Einstein condensation of photons in a dye-filled optical microcavity. The effect is of interest for fundamental studies and may lead to new coherent ultraviolet sources.

The past few years have seen a spectacular growth of interest in graphene. Efforts to produce large sheets of monolayer (or few-layer) graphene could receive a welcome boost from the simple procedure reported by these authors. They show how baking various solid carbon sources (for example polymer films) deposited on a metal catalyst substrate can produce either pristine graphene or doped graphene in a single step.

The effects of biodiversity on ecosystem function are usually studied within trophic levels. These authors conduct a large experiment across trophic levels to show how manipulations of plant diversity affect function in different groups. The effects are consistent across groups, but are stronger at adjacent trophic levels and in above-ground rather than below-ground groups.

The blood–brain barrier (BBB) is made up of vascular endothelial cells and was thought to have formed postnatally from astrocytes. Two independent studies demonstrate that this barrier forms during embryogenesis, with pericyte/endothelial cell interactions being critical to regulate the BBB during development. A better understanding of the relationship among pericytes, neuroendothelial cells and astrocytes in BBB function will contribute to our understanding of BBB breakdown during central nervous system injury and disease.

The blood–brain barrier (BBB) is made up of vascular endothelial cells and was thought to have formed postnatally from astrocytes. Two independent studies demonstrate that this barrier forms during embryogenesis, with pericyte/endothelial cell interactions being critical to regulate the BBB during development. A better understanding of the relationship among pericytes, neuroendothelial cells and astrocytes in BBB function will contribute to our understanding of BBB breakdown during central nervous system injury and disease.

p53 is an important tumour suppressor gene. Two papers now show in a Kras-driven lung cancer model that p53-mediated tumour suppression is only engaged late during tumour progression, when the Kras oncogenic signal reaches a threshold sufficient to activate the ARF–p53 pathway. Therefore, p53 re-expression in p53-deficient lung tumours does not restrict early stages of tumorigenesis, but induces tumour regression of more aggressive tumours.

p53 is an important tumour suppressor gene. Two papers now show in a Kras-driven lung cancer model that p53-mediated tumour suppression is only engaged late during tumour progression, when the Kras oncogenic signal reaches a threshold sufficient to activate the ARF–p53 pathway. Therefore, p53 re-expression in p53-deficient lung tumours does not restrict early stages of tumorigenesis, but induces tumour regression of more aggressive tumours.

The kinetochore is a large protein complex that assembles on centromeric DNA and captures microtubules to mediate chromosome separation. These authors report the first purification of functional kinetochores. They also show that kinetochore particles maintain load-bearing associations with assembling and disassembling ends of single microtubules and that tension increases the lifetimes of the attachments directly. These results provide evidence that tension selectively stabilises kinetochore–microtubule interactions.

Focal adhesions link the extracellular matrix by integrin receptors to cytoplasmic actin filaments and are fundamental to human physiology. These authors determine the molecular architecture of focal adhesions by mapping protein organization at the nanoscale level. The results demonstrate that focal adhesions possess a well-organized ultrastructure made up of at least three spatial and functional compartments that mediate their interdependent functions.

Mutations in ryanodine receptors can lead to severe genetic conditions in both cardiac and skeletal muscles. These authors report the X-ray crystal structure of a type 1 ryanodine receptor and pinpoint the exact locations of more than 50 disease-related mutations in the full-length receptor. The disease mutations seem to cause misfolding of an individual domain, to destabilize interactions between the three amino-terminal domains, or to otherwise affect one of the other domain interfaces.

Nanomaterials have evolved from innovation to application — and the career possibilities have blossomed.

How to thrive as a plant biologist in a biomedical research environment.

A 30% rise in students from China is behind record highs at US institutions.

Emerging nations challenging for top research spots.

Junior staff want more grant-applications help from institutions.

Pig in the middle.