Volume 520 Issue 7548

Editorials

Highway to health p.407

Africa has an ambitious and welcome plan for a continent-wide centre for disease control — but if the agency is to live up to its promise, it will need substantially better resources.

doi: 10.1038/520407a

Decoupled ideals p.407

‘Ecomodernist Manifesto’ reframes sustainable development, but the goal remains the same.

doi: 10.1038/520407b

More from Moore p.408

Moore's law is approaching physical limits: truly novel physics will be needed to extend it.

doi: 10.1038/520408a

News

News Features

The soil sleuth p.422

Forensic geologist Lorna Dawson has pioneered methods to help convict criminals using the dirt from their shoes.

doi: 10.1038/520422a

Degrees of separation p.426

Chemists hope to break China's monopoly on rare-earth elements by finding cheap, efficient ways to extract them from ore.

doi: 10.1038/520426a

News & Views

Illuminating the past p.438

The technique of optical dating was first reported 30 years ago, and has since revolutionized studies of events that occurred during the past 500,000 years. Here, two practitioners of optical dating assess its impact and consider its future.

doi: 10.1038/520438a

Pain-sensing TRPA1 channel resolved p.439

The TRPA1 ion channel activates pain pathways in response to noxious compounds. The structure of TRPA1 has now been solved, providing insight into how it functions. See Article p.511

doi: 10.1038/nature14383

Listening to quantum grains of sound p.441

An optomechanical device has allowed quanta, or 'grains', of mechanical vibration to be counted by optical means. The system may open up new possibilities in acoustics and thermal engineering. See Letter p.522

doi: 10.1038/520441a

Landscape inversion by stream piracy p.442

A model suggests that active deformation in mountains causes river networks to constantly reorganize, providing an explanation for the paradoxical formation of almost flat surfaces high in craggy mountain ranges. See Letter p.526

doi: 10.1038/520442a

The yin and yang of cortical oxytocin p.444

Female mice can learn to respond to distress calls from young mice — an ability that has now been found to be improved through signalling by the hormone oxytocin in the left auditory cortex of the brain. See Article p.499

doi: 10.1038/nature14386

Neuregulin 1 makes heart muscle p.445

Three studies reveal that augmentation of a signalling pathway involving the growth factor neuregulin 1 and its receptor protein ERBB2 can promote the generation of muscle cells in zebrafish, mice and infant heart tissue.

doi: 10.1038/520445a

Shared ancestry predicts disease levels p.446

Ecological factors such as host density are important predictors of disease incidence. But another key determinant may be the evolutionary history and relatedness of the host community. See Letter p.542

doi: 10.1038/520446a

Articles

Oxytocin enables maternal behaviour by balancing cortical inhibition p.499

A study of pup retrieval behaviour in mice shows that oxytocin modulates cortical responses to pup calls specifically in the left auditory cortex; in virgin females, call-evoked responses were enhanced, thus increasing their salience, by pairing oxytocin delivery in the left auditory cortex with the calls, suggesting enhancement was a result of balancing the magnitude and timing of inhibition with excitation.

doi: 10.1038/nature14402

Structure of the TRPA1 ion channel suggests regulatory mechanisms p.511

The high-resolution electron cryo-microscopy structure of the full-length human TRPA1 ion channel is presented; the structure reveals a unique ankyrin repeat domain arrangement, a tetrameric coiled-coil in the centre of the channel that acts as a binding site for inositol hexakisphosphate, an outer poor domain with two pore helices, and a new drug binding site, findings that collectively provide mechanistic insight into TRPA1 regulation.

doi: 10.1038/nature14367

Letters

In situ low-relief landscape formation as a result of river network disruption p.526

Landscapes on Earth retain a record of the tectonic, environmental and climatic history under which they formed. Landscapes tend towards an equilibrium in which rivers attain a stable grade that balances the tectonic production of elevation and with hillslopes that attain a gradient steep enough to transport material to river channels. Equilibrium low-relief surfaces are typically found at low elevations, graded to sea level. However, there are many examples of high-elevation, low-relief surfaces, often referred to as relict landscapes, or as elevated peneplains. These do not grade to sea level and are typically interpreted as uplifted old landscapes, preserving former, more moderate tectonic conditions. Here we test this model of landscape evolution through digital topographic analysis of a set of purportedly relict landscapes on the southeastern margin of the Tibetan Plateau, one of the most geographically complex, climatically varied and biologically diverse regions of the world. We find that, in contrast to theory, the purported surfaces are not consistent with progressive establishment of a new, steeper, river grade, and therefore they cannot necessarily be interpreted as a remnant of an old, low relief surface. We propose an alternative model, supported by numerical experiments, in which tectonic deformation has disrupted the regional river network, leaving remnants of it isolated and starved of drainage area and thus unable to balance tectonic uplift. The implication is that the state of low relief with low erosion rate is developing in situ, rather than preserving past erosional conditions.

doi: 10.1038/nature14354

Tungsten isotopic evidence for disproportional late accretion to the Earth and Moon p.530

Examination of three lunar samples reveals that the Moon’s mantle has an excess of the tungsten isotope 182W of about 20 parts per million relative to the present-day Earth’s mantle; this suggests that the two bodies had identical compositions immediately following the formation of the Moon, and that the compositions then diverged as a result of disproportional late accretion of chondritic material to the Earth and Moon.

doi: 10.1038/nature14355

Lunar tungsten isotopic evidence for the late veneer p.534

Precise measurements of the tungsten isotopic composition of lunar rocks show that the Moon exhibits a well-resolved excess of 182W of about 27 parts per million over the present-day Earth’s mantle: this excess is consistent with the expected 182W difference resulting from a late veneer with a total mass and composition inferred from previously measured highly siderophile elements.

doi: 10.1038/nature14360

Structure of the E. coli ribosome–EF-Tu complex at <3 Å resolution by Cs-corrected cryo-EM p.567

Single particle electron cryomicroscopy (cryo-EM) has recently made significant progress in high-resolution structure determination of macromolecular complexes due to improvements in electron microscopic instrumentation and computational image analysis. However, cryo-EM structures can be highly non-uniform in local resolution and all structures available to date have been limited to resolutions above 3 Å. Here we present the cryo-EM structure of the 70S ribosome from Escherichia coli in complex with elongation factor Tu, aminoacyl-tRNA and the antibiotic kirromycin at 2.65–2.9 Å resolution using spherical aberration (Cs)-corrected cryo-EM. Overall, the cryo-EM reconstruction at 2.9 Å resolution is comparable to the best-resolved X-ray structure of the E. coli 70S ribosome (2.8 Å), but provides more detailed information (2.65 Å) at the functionally important ribosomal core. The cryo-EM map elucidates for the first time the structure of all 35 rRNA modifications in the bacterial ribosome, explaining their roles in fine-tuning ribosome structure and function and modulating the action of antibiotics. We also obtained atomic models for flexible parts of the ribosome such as ribosomal proteins L9 and L31. The refined cryo-EM-based model presents the currently most complete high-resolution structure of the E. coli ribosome, which demonstrates the power of cryo-EM in structure determination of large and dynamic macromolecular complexes.

doi: 10.1038/nature14275