Research articles

An electronic analogue of a Michelson–Morley experiment, in which an electron wave packet bound inside a calcium ion is split into two parts and subsequently recombined, demonstrates that the relative change in orientation of the two parts that results from the Earth’s rotation reveals no anisotropy in the electron dispersion; this verification of Lorentz symmetry improves on the precision of previous tests by a factor of 100.

The Cancer Genome Atlas presents an integrative genome-wide analysis of genetic alterations in 279 head and neck squamous cell carcinomas (HNSCCs), which are classified by human papillomavirus (HPV) status; alterations in EGFR, FGFR, PIK3CA and cyclin-dependent kinases are shown to represent candidate targets for therapeutic intervention in most HNSCCs.

A subset of lung cancer cells with EGFR or BRG1 mutations shows selective sensitivity to a combination of EZH2 inhibitors with topoisomerase II inhibitors such as the commonly used chemotherapeutic drug etoposide.

Grains collected from comet 67P/Churyumov-Gerasimenko by the Rosetta mission come from a dusty crust that is predicted to be imminently shed as the comet nears the Sun; the grains are high in sodium and fluffy, not icy, suggesting that they are the precursors of interplanetary dust particles.

The emRiboSeq sequencing method is used to track polymerase activity genome-wide in vivo; despite Okazaki fragment processing, DNA synthesized by error-prone polymerase-α (Pol-α) is retained in vivo and comprises ∼1.5% of the genome, establishing Pol-α as an important source of genomic variability and providing a mechanism for site-specific variation in nucleotide substitution rates.

Parasites of the Theileria genus infect cattle and transform their host cells, a transformation that can be reversed by treatment with the drug buparvaquone; here, a Theileria homologue of the peptidyl-prolyl isomerase PIN1 is shown to be secreted into the host cell, where it promotes transformation and can be directly inhibited by buparvaquone.

The monocyclic β-lactam rings of the nocardicin family of antibiotics are biosynthesized by an unprecedented activity of non-ribosomal peptide synthetases, a mechanism that is distinct from the pathways to the other classes of β-lactam antibiotics.

A sub-ångström-resolution X-ray crystal structure of [NiFe] hydrogenase, with direct detection of the products of the heterolytic splitting of dihydrogen into a hydride bridging the Ni and Fe and a proton attached to the sulphur of a cysteine ligand.

Two genetically distinct populations of neurons in the subfornical organ of mice can either induce thirst and water-seeking behaviour or suppress thirst, regardless of the hydration status of the animal.

The facile synthesis of a stable Au(III) cationic complex is described; this gold catalyst exhibits hard, oxophilic Lewis acidity, enabling selective conjugate additions and a [2 + 2] cycloaddition reaction.

Observations of rapid, persistent elevation gains that occur on the ice surface above a subglacial lake as the lake is refilled with surface meltwater during the summer melt period in Greenland show that surface meltwater may be trapped and stored at the bed of an ice sheet, affecting ice dynamics downstream.

Genome-wide association studies are used to identify common genetic variants that affect the structure of selected subcortical regions of the human brain; their identification provides insight into the causes of variability in brain development and may help to determine mechanisms of neuropsychiatric dysfunction.

Apoptotic cell death is required for morphogenesis of the developing leg joint of fruitflies; using this model system, the authors show here that within apoptotic cells a transient pulling force exerted through a highly dynamic apico-basal myosin II cable-like structure acts as a mechanical signal to increase tissue tension and modify tissue shape.

Essential enzymes in genetically modified organisms are computationally redesigned to functionally depend on non-standard amino acids, thereby achieving biocontainment with unprecedented resistance to escape by evolution or by supplementation with environmental metabolites.

Time-resolved resonance Raman vibrational spectroscopy was used to study the mechanism of soluble methane monooxygenase and obtain structural information on the key reaction cycle intermediate, compound Q, which contains a unique dinuclear Fe^IV cluster that breaks the strong C-H bond of methane and inserts an oxygen atom (from O₂) to form methanol.

Construction of a series of genomically recoded organisms whose growth is restricted by the expression of essential genes dependent on exogenously supplied synthetic amino acids introduces novel orthogonal barriers between these engineered organisms and the environment, thereby creating safer genetically modified organisms.

Genome-wide localization and activity analysis of the de novo DNA methyltransferases DNMT3A and DNMT3B in mouse embryonic stem cells identifies overlapping and individual targeting preferences to the genome, including a role for DNMT3B in gene body methylation.

Initially weak episodic memories in humans can be selectively enhanced and consolidated following later emotional learning involving conceptually related information, suggesting a mechanism for how we can remember initially inconsequential information after a relevant later experience.

Nanomagnetic imaging has been used to obtain a palaeomagnetic time series of two pallasite meteorites, revealing that their convection was driven by core solidification, which would have caused long-lived magnetic fields in the cores of early Solar System planetary bodies.

Dissociating early from late fear memory retrieval in rats reveals that while the projection from the prelimbic prefrontal cortex to the amygdala is critical for fear memory retrieval at early time points, a separate circuit involving the paraventricular region of the dorsal midline thalamus is critical for fear memory retrieval at late time points, establishing the paraventricular region as a critical maintenance/retrieval node during the transition from short- to long-term fear memory.