News & Views in 2013

The implications of the X-ray emission patterns of galaxies hosting supermassive black holes have been contentious. Data from NASA's NuSTAR telescope seem to resolve the issue — at least for one such galaxy. See Letter p.449

The discovery that some viruses use a defence mechanism known as a CRISPR/Cas system beautifully illustrates the evolutionary tit-for-tat between viruses and the bacteria they infect. See Letter p.489

Rhesus macaques' responses to computer-animated images of lip-smacking monkey faces suggest that the jaw, tongue and lip oscillations that characterize human speech may have evolved from rhythmic primate facial expressions.

A ruthenium catalyst has been developed that, at a few parts per million, releases hydrogen gas from methanol, a simple bulk chemical. The advance might allow methanol to be used as a hydrogen source for fuelling vehicles. See Letter p.85

Exactly when motor-planning neurons function to produce a bird's song is debatable. New data suggest that bursts of activity in these cells mark sudden changes in the commands to the vocal organ. See Article p.59

The impact of a diet, no matter how rich it is, depends crucially on the host's resident gut microbes. Treatment of severe malnutrition with antibiotics may affect the composition of this microbiota to favour better use of nutrients.

The versatility of RNA seems limitless. The latest surprise comes from circular RNAs, which are found to counteract the function of another class of regulatory RNA — the microRNAs. See Article p.333 & Letter p.384

Chromosome-segregation errors during cell division may play a key part in tumour evolution. The long-awaited identification of a common genetic defect causing such errors comes with an interesting conceptual twist. See Letter p.492

A long-standing ambiguity has been whether quiescent cells located in intestinal crypt structures are stem cells. The answer seems to be yes and no, depending on how one defines the term stem cell. See Article p.65

The discovery that schistosomes possess adult stem cells could explain the long-term persistence of these parasitic worms in humans. Targeting a protein produced by the cells might damage schistosome defences. See Letter p.476

Genomic data hint at the possibility of human migration from India to Australia 4,230 years ago. However, the inference that these humans took along their dogs and tools is difficult to reconcile with previous reports.

Fast-growing 'defector mutants' can threaten the success of a bacterial infection. But one bacterial species prevails over these cheats by forming a subpopulation that has shut down expression of virulence genes. See Letter p.353

An analysis reveals the huge impact of human activity on the nitrogen cycle in China. With global use of Earth's resources rising per head, the findings call for a re-evaluation of the consumption patterns of developed societies. See Letter p.459

A bacterium and a fungus both use gene sequences that fail to optimize the production of circadian-clock proteins. Two studies reveal different reasons for the advantages of producing less protein. See Letters p.111 & p.116

Viruses that infect the SAR11 group of oceanic bacteria have finally been found and sequenced. Because SAR11 is ubiquitous, these viruses may be the most abundant in the oceans — and perhaps in the entire biosphere. See Letter p.357

A boron complex catalyses the addition of allyl groups — hydrocarbon motifs — to 'activated imines' in a relay-like process, generating synthetically useful compounds as single mirror-image isomers. See Letter p.216

An innovative use of measurements of atmospheric carbon dioxide constrains the possible range of carbon–cycle responses to climate change during the twenty-first century, lowering expectations of tropical-forest dieback. See Letter p.341

When massive stars die as supernovae, these explosions can be seen out to the 'edge of the Universe'. But the stars' nature is often unclear. New observations provide insight into the life of one such star before it exploded. See Letter p.65