Japan has introduced an unproven system to make patients pay for clinical trials.
The US Senate has just voted to defund one of the providers of aborted fetal tissue for research. Such research is too valuable to become embroiled in the bitter abortion debate.
Hard decisions on issues that will affect future generations should not be sidestepped.
Dwindling algae harvest imperils reagent essential for culturing microbes.
Representatives discuss ethical, social and legal issues that unite and divide them.
Five years after a failed insertion into the planet’s orbit, Akatsuki finally reaches its target.
Turquoise killifish genomes help to explain their 'live fast, die young' lifestyle.
Woods Hole Oceanographic Institution will spend insurance money for destroyed vehicle on lower-risk projects.
Decision throws construction of the Thirty Meter Telescope into question.
The use of aborted fetal tissue has sparked controversy in the United States, but many scientists say it is essential for studies of HIV, development and more.
Researchers are gaining insight into the causes of a devastating form of muscle wasting that is often the final stage of cancer and other diseases.
News & Views
Robust quantitative analyses of asymmetric division in certain cells in flies identify the major molecular players and, most interestingly, define a simple equation to explain this complex cellular process. See Letter p.280
Catalysts that contain two types of active site split long hydrocarbon molecules into more-useful shorter ones. Research into controlling the nanoscale separation of the sites challenges accepted design rules for such catalysts. See Letter p.245
Two bi-specific protein constructs have been designed that direct the body's T cells to kill HIV-infected cells. The feat provides a step on the path to removing the latent virus reservoir that persists in patients on antiretroviral therapy.
A study shows that, as Earth warms, global precipitation will increase by less than many models predict, because of increases in the amount of near-infrared sunlight absorbed by water vapour. See Letter p.249
The TOM complex guides precursor proteins from the cell's cytosolic fluid into organelles called mitochondria. Biochemical analyses reveal the architecture of this complex and show how precursor proteins pass through its narrow pores.
Standard planet-formation models have been unable to reconstruct the distributions of the Solar System's small, rocky planets and asteroids in the same simulation. A new analysis suggests that it cannot be done.
Three structures of the enzyme RNA polymerase III, which is responsible for the synthesis of abundant short RNAs, reveal the specializations that make it an adept terminator and reinitiator of transcription. See Article p.231
Regulatory T cells help to prevent autoimmune responses. A new imaging technique reveals that activation of these cells requires clustering with self-reactive effector T cells and sensing of the signalling protein interleukin-2. See Article p.225
The spectral gap problem—whether the Hamiltonian of a quantum many-body problem is gapped or gapless—is rigorously proved to be undecidable; there exists no algorithm to determine whether an arbitrary quantum many-body model is gapped or gapless, and there exist models for which the presence or absence of a spectral gap is independent of the axioms of mathematics.
Drosophila intestinal stem cells (ISCs) respond to changes in diet, particularly L-glutamate levels, by modulating Ca2+ signalling to adapt their proliferation rate; furthermore, Ca2+ is shown to be central to the response of ISCs to a wide range of dietary and stress stimuli.
RNA interference screens were used to identify chromatin-associated factors that impede reprogramming of somatic cells into iPS cells; suppression of the chromatin assembly factor CAF-1 enhances the generation of iPS cells by rendering chromatin more accessible to pluripotency transcription factors.
Autoantigen-presenting dendritic cells are shown to interact with both effector and regulatory T cells, and effector-produced IL-2 activates the transcription factor STAT5 in regulatory T cells, which in turn upregulates suppressive molecules and prevents autoimmunity.
RNA polymerase III (Pol III), the largest eukaryote polymerase yet characterized, transcribes structured small non-coding RNAs; here cryo-electron microscopy structures of budding yeast Pol III allow building of an atomic-level model of the complete 17-subunit complex, both unbound and while elongating RNA.
The dwarf planet (1) Ceres, the largest object in the main asteroid belt, is found to have localized bright areas on its surface; particularly interesting is a bright pit on the floor of the crater Occator that exhibits what is likely to be water ice sublimation, producing crater-bound haze clouds with a diurnal rhythm.
Infrared spectra of (1) Ceres acquired at distances of 82,000 to 4,300 kilometres from the surface indicate widespread ammoniated phyllosilicates; the presence of ammonia suggests that material from the outer Solar System was incorporated into Ceres.
The conversion of hydrocarbons to produce high-quality diesel fuel can be catalysed by bifunctional materials that contain a metal site and an acid site; it has been assumed that these sites should be as close as possible in order to enhance catalysis, but it is now shown that having them too close together can be detrimental to selectivity.
The magnitude of global precipitation increase predicted by climate models has a large uncertainty that has been difficult to constrain, but much of the range in predictions is now shown to arise from shortcomings in the modelling of atmospheric absorption of shortwave radiation; if the radiative transfer algorithms controlling the absorption were more accurate, the model spread would narrow and the mean estimate could be about 40% lower.
In metre-sized rock specimens, rock friction starts to decrease at a much smaller work rate than in centimetre-sized rock specimens, thus demonstrating that rock friction is scale-dependent.
An analysis of when children develop a sense of fairness (receiving less or more than a peer) is compared across seven different societies; aversion to receiving less emerges early in childhood in all societies, whereas aversion to receiving more emerges later in childhood and only in three of the seven societies studied.
Growing evidence from metagenome-wide association studies link multiple common disorders to microbial dysbiosis but effects of drug treatment are often not accounted for; here, the authors re-analyse two previous metagenomic studies of type 2 diabetes mellitus patients together with a novel cohort to determine the effects of the widely prescribed antidiabetic drug metformin and highlight the need to distinguish the effects of a disease from the effects of treatment on the gut microbiota.
The first formal evidence of the shared and independent ability of basal cells and luminal pro-genitors isolated from normal human mammary tissue and transduced with a single oncogene to initiate tumorigeneses when introduced into mice.
During postnatal development in mice, the growth factor FGF18 induces autophagy in the chondrocyte cells of the growth plate to regulate the secretion of type II collagen, a process required for bone growth.
It is widely accepted that contraction of skeletal muscle and the heart involves structural changes in actin-containing thin filaments to allow binding of myosin motors from neighbouring thick filaments, thus driving filament sliding; here, X-ray diffraction of single skeletal muscle cells reveals that this thin-filament mechanism can regulate muscle contraction against low load, but high-load contraction requires a second permissive step involving a structural change in the thick filament.
Central spindle asymmetry, generated by the kinesin Klp10A and its antagonist Patronin, polarizes endosome motility and provides a mechanism for the asymmetric segregation of signalling endosomes observed in a variety of asymmetrically dividing cell types.
Common fragile sites (CFSs) are difficult-to-replicate regions of eukaryotic genomes that are sensitive to replication stress and that require resolution by the MUS81–EME1 endonuclease to re-initiate POLD3-dependent DNA synthesis in early mitosis; this study defines the specific pathway of events causing the CFS fragility phenotype.