Volume 527 Issue 7577

Editorials

Universities’ value p.133

Proposals for UK higher education contain some positive points amid the financial gloom.

doi: 10.1038/527133b

A breath of fresh air p.133

The decision to use the Montreal Protocol to reduce the impact of refrigerants on global warming is a step forward ahead of the Paris climate summit.

doi: 10.1038/527133a

Radio interference p.134

Conflict at the Arecibo Observatory highlights the need for funders to become more flexible.

doi: 10.1038/527134a

News

News Features

News & Views

DNA repair without flipping out p.168

Time-resolved molecular snapshots of the bacterial enzyme AlkD reveal an unprecedented mechanism for the recognition and removal of damaged bases in DNA, with implications for cell biology and cancer therapy. See Letter p.254

doi: 10.1038/nature15646

A small star with an Earth-like planet p.169

A rocky planet close in size to Earth has been discovered in the cosmic vicinity of our Sun. The small size and proximity of the associated star bode well for studies of the planet's atmosphere. See Letter p.204

doi: 10.1038/527169a

The enemy of my enemy is my friend p.170

Reactive oxygen species have been viewed as stress-inducing molecules that promote cancer initiation. But new evidence indicates that oxidative stress can be beneficial — inhibiting the spread of a cancer to other sites. See Article p.186

doi: 10.1038/nature15644

Deadly combination p.172

New evidence suggests that seismic waves from the Chicxulub meteorite impact doubled the eruption rate of lavas on the opposite side of the planet — a combination that led to the mass extinction at the end of the Cretaceous period.

doi: 10.1038/527172a

A rewired food web p.173

Climate change is causing large fish species to move into arctic marine environments. A network analysis finds that these fishes, with their generalist diets, add links to the existing food web that may alter biodiversity and web stability.

doi: 10.1038/nature16311

Liquefied molecular holes p.174

Porous solids have many uses in the chemical industry, which has stimulated the development of several generations of such materials. A new generation has now arrived, with the report of permanently porous liquids. See Letter p.216

doi: 10.1038/527174a

Human sleep before the industrial era p.176

A quantitative study of sleep patterns in three pre-industrial societies implies that our natural sleep duration is close to seven hours, and that sleep cycles are determined by environmental temperature as well as the light–dark cycle.

doi: 10.1038/527176a

Higher costs of climate change p.177

An attempt to reconcile the effects of temperature on economic productivity at the micro and macro levels produces predictions of global economic losses due to climate change that are much higher than previous estimates. See Letter p.235

doi: 10.1038/nature15643

Articles

Basomedial amygdala mediates top-down control of anxiety and fear p.179

Activation of the ventral medial prefrontal cortex–basomedial amygdala pathway is shown to suppress anxiety and fear-related freezing in mice, thus identifying the basomedial amygdala (and not intercalated cells, as posited by earlier models) as a novel target of top-down control.

doi: 10.1038/nature15698

Oxidative stress inhibits distant metastasis by human melanoma cells p.186

Human melanoma cells grown in mice experience high levels of oxidative stress in the bloodstream such that few metastasizing cells survive to form tumours; the rare melanoma cells that successfully metastasize undergo metabolic changes that increase their capacity to withstand this stress, and antioxidant treatments increase metastasis formation by human melanoma cells, while inhibiting antioxidant pathways had the reverse effect.

doi: 10.1038/nature15726

BCL11A enhancer dissection by Cas9-mediated in situ saturating mutagenesis p.192

A CRISPR-Cas9 approach is used to perform saturating mutagenesis of the human and mouse BCL11A enhancers, producing a map that reveals critical regions and specific vulnerabilities; BCL11A enhancer disruption is validated by CRISPR-Cas9 as a therapeutic strategy for inducing fetal haemoglobin by applying it in both mice and primary human erythroblast cells.

doi: 10.1038/nature15521

Letters

A rocky planet transiting a nearby low-mass star p.204

A low-mass star that is just 12 parsecs away from Earth is shown to be transited by an Earth-sized planet, GJ 1132b, which probably has a rock/iron composition and might support a substantial atmosphere.

doi: 10.1038/nature15762

Entangling two transportable neutral atoms via local spin exchange p.208

Spin-entangled states between two neutral atoms in different optical tweezers are prepared by combining them in the same optical tweezer and allowing for controlled interactions, after which the particles are dynamically separated in space and their entanglement is maintained.

doi: 10.1038/nature16073

Liquids with permanent porosity p.216

Porous materials find use in applications such as gas separation, drug delivery and energy storage, but have hitherto been solid rather than liquid; now a combination of cage molecules and a crown-ether solvent that cannot enter the cage molecules is used to create a porous liquid that can solubilize methane gas better than non-porous liquids.

doi: 10.1038/nature16072

Deep-time evolution of regeneration and preaxial polarity in tetrapod limb development p.231

Salamanders are the only tetrapod that can fully regenerate their limbs and tail, a capacity that might be linked to their unique preaxial mode of limb development; here, data from fossils reveal the existence of preaxial polarity in various amphibians from the Carboniferous and Permian periods, suggesting that salamander-like regeneration is an ancient feature of tetrapods that was subsequently lost at least once in the lineage leading to amniotes.

doi: 10.1038/nature15397

The DNA glycosylase AlkD uses a non-base-flipping mechanism to excise bulky lesions p.254

Crystal structures of the DNA glycosylase AlkD with DNA containing various modified bases show that neither substrate recognition nor catalysis use a base-flipping mechanism; instead, AlkD scans the phosphodeoxyribose backbone for increased cationic charge imparted by the alkylated base, and then uses the positive charge to facilitate cleavage of the glycosidic bond, thus explaining the specificity of AlkD for cationic lesions.

doi: 10.1038/nature15728