US lawmakers are asserting their place in the human genetic-modification debate.
A failed crop trial of genetically modified wheat stil provides crucial lessons for those battling to provide the planet's growing population with a sustainable food supply.
Smartphone camera set to come to the aid of sleuths, scientists and wine lovers.
Researchers hope the genetically engineered animals will speed past regulators.
Gains from two-year fund-raising frenzy will aid the early detection of tumours.
North America’s herbaria wilt under pressure for space and cash.
Large study of nuclear workers shows that even tiny doses slightly boost risk of leukaemia.
Dutch order to cut emissions opens door for citizens' lawsuits elsewhere.
Researchers are racing to determine whether forests will continue to act as a brake on climate change by soaking up more carbon.
Working out how to build ethical robots is one of the thorniest challenges in artificial intelligence.
News & Views
The finding of pharyngeal teeth and circumoral mouthparts in fossils of the Cambrian lobopodian animal Hallucigenia sparsa improves our understanding of the deep evolutionary links between moulting animals. See Letter p.75
A smartphone camera, patterned with arrays of filters made from colloidal suspensions of coloured particles, has been transformed into a powerful tool for spectral analysis. See Letter p.67
A randomized controlled trial of four financial-incentive programmes for smoking cessation finds that reward-based schemes lead to sustained abstinence, but low public acceptability of such schemes threatens their adoption.
Analyses of images taken by the Rosetta spacecraft reveal the complex landscape of a comet in rich detail. Close-up views of the surface indicate that some dust jets are being emitted from active pits undergoing sublimation. See Letter p.63
Wild populations of an Australian lizard have sex chromosomes and also exhibit temperature-controlled sexual development, providing insight into how these two sex-determining mechanisms may evolve back and forth. See Letter p.79
Combinations of spatially and temporally restricted transcription factors are shown to coordinate movement in nematode worms by controlling the formation of synaptic connections to and from motor neurons. See Letter p.83
This study determines the structure of the spliceosomal tri-snRNP complex (containing three small nuclear RNAs and more than 30 proteins) by single-particle cryo-electron microscopy; the resolution is sufficient to discern the organization of RNA and protein components involved in spliceosome activation, exon alignment and catalysis.
Transcription-blocking DNA lesions result in chromatin displacement of core spliceosomes containing U2 and U5 snRNPs; consequently, R-loops containing the nascent transcript are formed, which activate ATM in a feed-forward fashion to influence spliceosome dynamics and alternative splicing.
Massive galaxy clusters are filled with a hot, turbulent and magnetized intra-cluster medium, whose energy is derived from gravitational energy; the energy components of this medium are now shown to be ordered according to a permanent hierarchy, in which the ratio of thermal to turbulent to magnetic energy densities remains virtually unaltered over time.
The size and spatial distribution of pits on comet 67P/Churyumov–Gerasimenko, which are active and probably created by a sinkhole process, imply that large heterogeneities exist in the physical, structural or compositional properties of the first few hundred metres below the current cometary surface.
An efficient, cost effective microspectrometer that consists of a two-dimensional absorptive filter array of 195 different colloidal quantum dots is presented, and its performance demonstrated by measuring shifts in spectral peak positions as small as one nanometre.
The North Atlantic Oscillation (NAO) is an important source of climate variability in the Northern Hemisphere; here, a model-tested reconstruction of the NAO for the past millennium reveals that positive NAO phases were predominant during the thirteenth and fourteenth centuries, but not during the whole medieval period.
A re-analysis of the 508-million-year-old stem-group onychophoran Hallucigenia sparsa from the Burgess Shale shows that its anterior gut has structures that indicate evolutionary links with more disparate phyla such as nematodes and kinorhynchs; Hallucigenia now provides concrete evidence of structures that might have existed in the last common ancestor of the Ecdysozoa, previously a matter of conjecture.
The first report of reptile sex reversal in the wild and rapid transition between genetic and environmental sex determination in the Australian bearded dragon (Pogona vitticeps)
Neuronal synapses need to be formed at the right time and the right place during nervous system development; here, three gene-regulatory factors (the UNC-30, LIN-14 and UNC-55 DNA-binding proteins) are shown to operate in an intersectional manner to control the expression of a novel synaptic organizer molecule, OIG-1.
Little is known about how individual cells within a group of cells exposed to the same external signals can produce a specific individual response to their local microenvironment; a quantitative analysis of cell crowding reveals that single cells can autonomously sense local crowding though their ability to spread and activate focal adhesion kinase (FAK), which ultimately results in changes in cellular lipid composition.
The tumour microenvironment may contribute to tumorigenesis owing to mechanical forces such as fibrotic stiffness or mechanical pressure caused by the expansion of hyper-proliferative cells. Here we explore the contribution of the mechanical pressure exerted by tumour growth onto non-tumorous adjacent epithelium. In the early stage of mouse colon tumour development in the Notch+Apc+/1638N mouse model, we observed mechanistic pressure stress in the non-tumorous epithelial cells caused by hyper-proliferative adjacent crypts overexpressing active Notch, which is associated with increased Ret and β-catenin signalling. We thus developed a method that allows the delivery of a defined mechanical pressure in vivo, by subcutaneously inserting a magnet close to the mouse colon. The implanted magnet generated a magnetic force on ultra-magnetic liposomes, stabilized in the mesenchymal cells of the connective tissue surrounding colonic crypts after intravenous injection. The magnetically induced pressure quantitatively mimicked the endogenous early tumour growth stress in the order of 1,200 Pa, without affecting tissue stiffness, as monitored by ultrasound strain imaging and shear wave elastography. The exertion of pressure mimicking that of tumour growth led to rapid Ret activation and downstream phosphorylation of β-catenin on Tyr654, imparing its interaction with the E-cadherin in adherens junctions, and which was followed by β-catenin nuclear translocation after 15 days. As a consequence, increased expression of β-catenin-target genes was observed at 1 month, together with crypt enlargement accompanying the formation of early tumorous aberrant crypt foci. Mechanical activation of the tumorigenic β-catenin pathway suggests unexplored modes of tumour propagation based on mechanical signalling pathways in healthy epithelial cells surrounding the tumour, which may contribute to tumour heterogeneity.
The critical effectors of MYC overexpression during lymphomagenesis in transgenic mice are defined.
Calcium potently stimulates proteolysis by endogenous rhomboid-4, an intramembrane protease that contains a cytoplasmic calcium-binding EF-hand domain.
Structures of actin-like ParM filaments at near-atomic resolution and their arrangements into doublets reveal how subunits and filaments come together to segregate low-copy-number plasmid R1 in Escherichia coli, producing the simplest known mitotic machinery.
The first structures of the mammalian phosphofructokinase-1 tetramer are reported, for the human platelet isoform, in complex with ATP–Mg2+ and ADP.