Volume 457 Issue 7229, 29 January 2009

The conviction of two Iranian AIDS physicians violates international norms of justice and threatens to undermine collaborations between Iranian scientists and their colleagues elsewhere.

Obama's pledge to set US science in its rightful place requires a dose of reality from researchers.

How to evaluate a nation's scientific integrity.

US regulatory agency gives the go-ahead for first clinical trials of a human embryonic stem-cell treatment.

US nuclear-fusion project prepares to mimic the Sun.

Prison sentence threatens to undermine scientific cooperation.

The international treaty drawn up to tackle ozone-destroying substances is gearing up to curb greenhouse gases. Jeff Tollefson reports.

Drug giant chases stake in biologics.

Study casts doubt on iron-induced carbon sequestration.

John Beddington under fire for defending government policy.

Package aims to entice high-flyers back home.

By turning neurons technicolour, Jeff Lichtman exposed the brain's wiring. Jonah Lehrer meets the 'unapologetic cell biologist' with ambitions to map every connection in the human brain.

Are people's interactions driven by a primitive, non-linguistic type of communication? Mark Buchanan looks at how modern technology can reveal the basis of our powers of persuasion.

For human-subjects research, maximum regulation does not mean maximum protection. Stop regulating minimal risk research, say Scott Kim, Peter Ubel and Raymond De Vries.

The global problem of a safe and reliable supply of radioactive isotopes for use in critical hospital procedures can be solved with accelerators, not nuclear reactors, says Thomas Ruth.

Palaeontology in China has been invigorated by highly organized efforts to dig up bones for use in traditional Chinese medicine, explains Xu Xing.

Can visual arts stimulate creativity in the science laboratory? A new biochemistry building for the University of Oxford might provide the answer, finds Georgina Ferry.

Which human genes have been hotspots for positive selection? Analyses of the top candidates reveal, not genes subject to such selection, but genes that have probably been subject to biased DNA repair.

Cells of the adaptive immune system hold a grudge: on re-encountering a pathogen, they show a robust protective response. It seems that natural killer cells of the innate immune system might also have this ability.

Hopes are that the emergent family of iron-based superconductors, the pnictides, could act as a Rosetta stone in decoding the two-decade mystery of superconductivity observed at high temperatures.

The drought tolerance of sorghum is just one of the features that make it a valuable crop plant. There is much for agronomists to learn from the complete genome sequence of this type of grass.

The development of synthetic routes to unusual and complex molecules frequently leads to surprising lessons about chemical reactivity. The first synthesis of a marine toxin provides just such a lesson.

A rare example of gene incompatibility between two species of budding yeast has been found. This discovery of elusive 'speciation' genes adds to other reproductive-isolation mechanisms operating in yeasts.

Sorghum is an African grass that is grown for food, animal feed and fuel. The current paper presents an initial analysis of the ∼730 megabase genome of Sorghum bicolor. Genome analysis and its comparison with maize and rice shed light on grass genome evolution and also provide insights into the evolution of C₄ photosynthesis, as well as protein coding genes and miRNAs that might contribute to sorghum's drought tolerance.

Recent evidence has suggested the existence of immunological memory in natural killer (NK) cells. This paper confirms and extends the earlier observation, providing direct evidence that memory NK cells are more effective than naive NK cells in controlling viral infection in vivo.

This paper reports 8-µm photometric observations of the planet HD 80606b during a 30-hour interval bracketing the periastron passage of its extremely eccentric 111.4 day orbit. As the planet received its strongest irradiation its 8-µm brightness temperature increased from ∼800 K to ∼1500 K over a six-hour period. The radiative time constant at the planet's 8-µm photosphere is ∼4.5 hours, as compared to 3–5 days in Earth's stratosphere.

It is shown that the superconducting properties of (Ba,K)Fe₂As₂ are quite isotropic. Such behaviour is strikingly different from all previously known layered superconductors, and indicates that reduced dimensionality in these compounds is not a prerequisite for 'high-temperature' superconductivity.

Electron density waves have been observed in many families of superconductors. Recent measurements seem to show that the properties of the iron pnictides are in good agreement with band structure calculations that do not include additional ordering, implying no relation between density waves and superconductivity in those materials. It is reported that the electronic structure of Ba_1-xK_xFe₂As₂ is in sharp disagreement with those band structure calculation, instead revealing a reconstruction characterized by a (π, π) wave vector.

This paper presents the total synthesis of a chlorosulpholipid cytotoxin, leading to confirmation of the proposed structure and the discovery of unanticipated reactivity of polychlorinated hydrocarbons. The concise synthetic approach should enable synthetic chemists to prepare sufficient quantities to facilitate biological studies.

It is found that carbon export fluxes to the deep ocean from a highly productive, naturally iron-fertilized region of the sub-Antarctic Southern Ocean are two to three times larger than the carbon export fluxes from an adjacent high-nutrient low-chlorophyll area not fertilized by iron. These findings support the hypothesis that increased iron supply to the glacial sub-Antarctic may have directly enhanced carbon export to the deep ocean.

Eutrophication of coastal waters can cause sulphide blooms, which are toxic to marine life. It is shown that these blooms can be rapidly detoxified by sulphide-oxidizing bacteria. This finding suggests that sulphide blooms may occur more frequently than previously appreciated and that the responsible bacterial groups are important to protect coastal ecosystems.

The common dust mite allergen Der p 2 is shown to replace MD-2 as the lipopolysaccharide-binding component and facilitates signalling through TLR4. It is suggested that Der p 2 tends to be targeted by adaptive immune responses because of its auto-adjuvant properties.

This paper shows that during early myogenesis, Wnt11 plays an essential role in the oriented elongation of the myocytes. In addition, Wnt11 mediates this effect through the evolutionary conserved planar cell polarity pathway (PCP), which is downstream of the Wnt/β-catenin-dependent pathway. It is also shown that localized ectopic source of Wnt11 can change the orientation of myocytes, indicating that Wnt11 acts as a directional cue in this process.

Adhesion to host cells is essential for virulence of many bacterial pathogens, including pathogenic Escherichia coli. An adhesion mechanism that relies on the secreted protein EtpA is now presented. EtpA attaches to both the bacterial flagella tip and the host cell, providing an adherence mechanism that is important for E. coli pathogenesis and may be present in many other pathogens that possess EtpA homologues.

Mutations in BRAF and NRAS that lead to constitutive activation of MAP kinase signalling have been found at high frequencies in many melanomas. However, they have not been found in the uveal melanomas and blue nevi subtypes of melanoma. This paper shows that these subtypes instead show frequent activating mutations in the G protein α-subunit GNAQ, also leading to the activation of the MAP kinase pathway.

It is shown that the cell surface protein prominin 1 (also known as CD133) marks stem cells in the mouse intestine. Using lineage-tracing experiments, it is shown that intestinal tumours can originate in these cells when the Wnt signalling pathway is aberrantly activated.

Intestinal tumours can originate from Lgr5⁺ intestinal stem cells after genetic activation of the Wnt signalling pathway.

It is shown that type of repair pathway, known as postreplication repair, permits cells to replicate their DNA when it is damaged, thereby avoiding the activation of a cellular response that would inhibit proliferation.

Carbohydrates are important in many biological processes, but the full extent of their distribution and function remains unclear. Advances in technology are now reveal those secrets. Nathan Blow reports.

The government's assessment of UK colleges and universities sets up a waiting game for new funds and recruitment. Karen Kaplan reports.

The improbable dream.