Volume 512 Issue 7512, 7 August 2014

The next research commissioner for the European Union will need the drive and confidence to clear a daunting in-tray, argues Colin Macilwain.

The week in science: Death of top Japanese stem-cell scientist; instruments picked for Mars rover; and drought tightens grip on California.

Close approach and violent interaction of stars in η Carinae system will provide rare insight into stellar enigma.

Immunization against pneumococcus in Africa also reduces levels of antibiotic resistance.

Leading directory tightens listing criteria to weed out rogue journals.

PCORI clinical-research initiative will collect information on some 30 million people.

The race is on to build a machine that can synthesize any organic compound. It could transform chemistry.

Mahlon C. Kennicutt II, Steven L. Chown and colleagues outline the most pressing questions in southern polar research, and call for greater collaboration and environmental protection in the region.

Philip Ball unveils the scientific iconography in Albrecht Dürer's enigmatic engraving Melencolia I.

'Seed' molecules have been made that enable synthesis of just one kind of single-walled carbon nanotube, rather than a mixture of species. This paves the way for the preparation of pure samples of any nanotube species. See Letter p.61

A comparison of colorectal cancer and normal cells from 103 patients identifies dozens of genes that are differently expressed in tumour cells as a result of altered regulation of transcription. See Letter p.87

Two studies of amyloid-β protein aggregates, which cause Alzheimer's disease, find that different conformations of the aggregates can define different strains of the disorder, drawing parallels with prion diseases.

Some stars explode in thermonuclear supernovae, but understanding of why this occurs comes mainly from indirect clues. Now, the progenitor of a member of a strange class of such explosions may have been detected directly. See Letter p.54

Giving monkeys antiretroviral therapy from just three days after exposure to simian immunodeficiency virus does not prevent a subsequent rebound of viral replication, suggesting that viral reservoirs are established early. See Letter p.74

Mice deficient in the EDA protein lack normal tooth features. Restoring EDA in embryonic teeth at increasing doses has now been found to recover these dental features in a stepwise pattern that mimics evolution. See Article p.44

Net primary production is affected by temperature and precipitation, but whether this is a direct kinetic effect on plant metabolism or an indirect ecological effect mediated by changes in plant age, plant biomass or growing season length is unclear — this study develops metabolic scaling theory to be able to answer this question and applies it to a global data set of plant productivity, concluding that it is indirect effects that explain the influence of climate on productivity, which is characterized by a common scaling relationship across climate gradients.

Gradual changes that occur to mammalian tooth morphology across evolutionary time were modelled in vitro and in vivo by modulation of signalling pathways in the mouse, and computer modelling was used to provide further analysis of the parameters influencing tooth morphology.

The crystal structures of thalidomide and its derivatives bound to the E3 ligase subcomplex DDB1–CRBN are shown; these drugs are found to have dual functions, interfering with the binding of certain cellular substrates to the E3 ligase but promoting the binding of others, thereby modulating the degradation of cellular proteins.

The detection of the luminous, blue progenitor system of the type Iax supernova 2012Z suggests that this supernova was the explosion of a white dwarf accreting material from a helium-star companion.

The ability of individual ions trapped in separate potential wells to simulate spin–spin interactions is demonstrated by tuning the Coulomb interaction between two ions, independently controlling their local wells and entangling their internal states with a fidelity of approximately 0.82.

Present preparation methods fail to meet fully the demand for structurally pure single-walled carbon nanotubes; surface-catalysed cyclodehydrogenation reactions are now shown to convert precursor molecules deposited on a platinum(111) surface into ultrashort nanotube seeds that can then be grown further into defect-free and structurally pure single-walled carbon nanotubes of single chirality.

GEOTRACES sampling of deep water from the Atlantic, Pacific and Southern oceans allows an estimate of the amount (tripled in surface waters) and distribution (two-thirds increase in water less than a thousand metres deep) of anthropogenic mercury accumulating in the global ocean.

Pathogenesis of rheumatoid arthritis depends critically on the NLRP3 inflammasome/interleukin-1 signalling axis.

Reservoirs of virus infection represent the most important reason why HIV-1 cannot be cured with current antiretroviral drugs; now the refractory viral reservoir is shown to be seeded as early as 3 days after infection in a monkey model, even before the virus is detected in the blood.

Myeloproliferative neoplasms are caused by mutations in the haematopoietic stem cell (HSC) compartment, and here the authors show that the HSC niche contributes to the pathogenesis; sympathetic innervation of mesenchymal stem cells (MSCs) is reduced in the bone marrow of patients, which leads to reduced MSC numbers and increased mutant HSC expansion, and restoring sympathetic regulation of MSCs with neuroprotective/sympathomimetic drugs prevents mutant HSC expansion.

Pvt1 overexpression in mice contributes to high Myc levels due to 8q24.21 gain and to MYC-driven tumorigenesis.

Examination of allele-specific expression identifies 71 genes with excess somatic cis-regulatory effects in colorectal cancer (CRC), and 1,693 and 948 expression quantitative trait loci (eQTLs) in normal samples and tumours, respectively (with 36% of tumour eQTLs exclusive to CRC); tumour-specific eQTLs are more enriched for low CRC genome-wide association study P values and accumulate more somatic mutations than shared eQTLs, suggesting a role as germline-derived cancer regulatory drivers.

Systematically assaying the activity of 7,705 candidate enhancers during Drosophila embryogenesis shows that nearly half are active in the embryo and display dynamic spatial patterns during development; enhancer activity is matched to expression patterns of putative target genes and predictive cis-regulatory motifs are identified.

A high-resolution map of enhancer three-dimensional contacts during Drosophila embryogenesis shows that although local regulatory interactions are frequent, long-range interactions are also very common; unexpectedly, most interactions appear unchanged between tissues and across development and are formed prior to gene expression, indicating that transcription initiates from preformed enhancer–promoter loops, which are associated with paused polymerase.

In the transport cycle of Yiip, zinc(ii) binding triggers a highly localized, all-or-nothing change of water accessibility to the transport site and an adjacent hydrophobic gate.

Interest in energy-storage research is growing, opening up opportunities for chemists with interdisciplinary skills.

US contract research organizations are multiplying to meet drug-makers' outsourcing needs.

US association argues for graduate assistants' right to unionize.

All that matters.