Research articles

In mice, provision of butyrate—a short-chain fatty acid produced by commensal microorganisms during starch fermentation—facilitates extrathymic generation and differentiation of Foxp3⁺ regulatory T cells, demonstrating that metabolic by-products are sensed by cells of the immune system and affect the balance between pro- and anti-inflammatory cells.

Most known ferroelectric photovoltaic materials have very wide electronic bandgaps (that is, they absorb only high-energy photons) but here a family of perovskite oxides is described that have tunable bandgaps, allowing their use across the whole visible-light spectrum.

Plants defend themselves against attackers by producing bioactive secondary metabolites such as triterpene saponins; here, the endoplasmic-reticulum-associated degradation (ERAD) system is shown to control the activity of HMGR, the rate-limiting enzyme in the supply of the terpene precursor isopentenyl diphosphate, thereby preventing unrestrained saponin production and ensuring the integrity of plant development.

Growth of a flagellum outside the bacterial cell proceeds by successive subunit acquisition from the cell export machinery to form a chain that is pulled to the flagellum tip, where subunit crystallization provides the entropic force to drive the process.

A chromatin interaction analysis with paired-end tagging (ChIA-PET) approach is used to delineate chromatin interactions mediated by RNA polymerase II in several different stem-cell populations; putative long-range promoter–enhancer interactions are inferred, indicating that linear juxtaposition does not necessarily guide enhancer target selection and prevalent cell-specific enhancer usage.

Two private, heterozygous mutations in two functionally related genes, GUCY1A3 and CCT7, are identified in an extended family with myocardial infarction; these genes encode proteins that work together to inhibit platelet activation after nitric oxide stimulation, suggesting a link between impaired nitric oxide signalling and myocardial infarction risk.

Although olivine was expected to occur within the deep, south-pole basins of asteroid Vesta, which are thought to be excavated mantle rocks, spectral data from NASA’s Dawn spacecraft show that it instead occurs as near-surface materials in Vesta’s northern hemisphere.

Analysis of video records of the Chelyabinsk superbolide of 15 February 2013 show that its orbit was sufficiently similar to the orbit of asteroid 86039 (1999 NC43) to suggest that the two were once part of the same object.

Populations of millions of colloidal rolling particles are shown to self-organize to achieve coherent motion; comparison between experiment and theory based on the microscopic interactions between these ‘rollers’ suggests that hydrodynamic interactions promote the emergence of the collective motion.

The damage caused by the asteroid 17–20 metres in diameter that exploded over Chelyabinsk, Russia, on 15 February 2013 is estimated here to have an energy equivalent to about 500 kilotons of TNT.

The structure of molten basalt up to 60 GPa by means of in situ X-ray diffraction is described, with the coordination of silicon increasing from four under ambient conditions to six at 35 GPa, and subsequent reduced melt compressibility, which seems to affect siderophile-element partitioning.

The spliceosome is shown to catalyse splicing through the RNA and not the protein components of the spliceosome; pre-messenger RNA splicing requires U6 snRNA acting by a mechanism similar to that used by group II self-splicing introns.

Human immunodeficiency virus (HIV)-1 is shown here to depend on the recruitment to the HIV-1 capsid of specific cofactors involved in orchestrating nuclear entry and targeting; when these capsid–cofactor interactions are prevented either by virus mutation, cofactor depletion or pharmacological inhibition of cofactor recruitment, viral DNA can be detected by innate immune sensors.

This study shows that in monkeys making context-dependent decisions, task-relevant and task-irrelevant signals are confusingly intermixed in single units of the prefrontal cortex, but are readily understood in the framework of a dynamical process unfolding at the level of the population; a recurrently connected neural network model reproduces key features of the data and suggests a novel mechanism for selection and integration of task-relevant evidence towards a decision.

Using in vivo lineage tracing in mice and sorted cells in culture, the ability of stably committed cells to dedifferentiate into basal stem cells in the mouse trachea is investigated: the findings suggest that the dedifferentiation of committed cell types into stem cells may contribute generally to regeneration in higher vertebrates in different organ and injury contexts.

In neonatal mice, susceptibility to infection is due to an enriched subset of arginase-2-expressing CD71⁺ erythroid cells, which suppresses the systemic activation of immune cells, thereby protecting neonates against aberrant inflammation triggered by colonization with commensal microbes.

A prospective longitudinal study identifies the earliest known indicator of social disability in human infancy: decline in attention to others’ eyes in infants who are later diagnosed with autism; the decline is evident already within the first 2 to 6 months of life, which reveals the early unfolding of the disorder but also offers a promising opportunity for the future of early intervention.

The crystal structures of three forms of Escherichia coli acyl carrier protein engaging LpxD, an acyltransferase in the lipid A biosynthetic pathway, are reported.

Brown adipose tissue-enriched lysine methyltransferase EHMT1 is an essential enzyme in the PRDM16–C/EBP-β transcriptional complex that controls brown adipose cell fate and energy metabolism.

Acceleration of relativistic electrons in a dielectric laser accelerator at high electric field gradients is reported, setting the stage for the development of future multi-staged accelerators of this type.