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On 14 September, the California Institute for Regenerative Medicine (CIRM) appointed Australian biologist Alan Trounson as its new president. The CIRM has lacked a permanent director since neuroscientist Zach Hall departed in April, amidst rumours of tension between himself and Robert Klein, chair of the $3-billion agency's board.
What role should the federal government have in pre-college science education? David Goldston looks at why the US Congress is acting now to help define that.
Can a stage spectacular based on a TV documentary bring science to life and please the punters too? Brendan Maher joins a palaeontologist to watch the dinosaurs walk.
One strategy for reducing catastrophic floods invokes protecting or regenerating forests that lie upstream of a threatened region. Support for this approach comes from a global-scale analysis of flood risk.
For practical and ethical reasons, researchers are on the lookout for ways to reprogramme one mature cell type into another. In one case, this might be as easy as switching off a single gene.
Well-established models of nuclei describe properties such as shells and magic numbers. But how do these predictions stand up to scrutiny for exotic, unstable nuclei? Pretty well, according to the latest study.
Predictions drawn from experiments on the growth of molar teeth in mice, and applied to a wide range of related species, provide a remarkable connection between developmental and evolutionary biology.
Quantum mechanics using whole electrical circuits might seem a far-fetched idea. But make the circuits superconducting, and they can be used to send and collect single photons, rather like atoms do — only better.
A test-bed system for examining how development guides evolutionary change is the arrangement of molars in mice. The first molar is larger than the one behind, which is in turn larger than the third, hindmost molar. Experimental investigations have shown that molar development follows an inhibitory cascade model, and the results are used to show how this simple model governs the variation in molar size and number in rodent evolution.
The enzyme uracil DNA glycosylase does not actively extrude just the uracil base from the DNA helix to facilitate its removal; instead, transient, passive opening of thymine: adenine and uracil: adenine base pairs allows both thymine and uracil to become extrahelical, but only uracil can subsequently fit in the active site.
One of two papers that demonstrate the communication of individual quantum states between superconducting qubits via a quantum bus. This quantum bus is a resonant cavity formed by a superconducting transmission line of several millimetres. Quantum information, initially defined in one qubit on one end, can be stored in this quantum bus and at a later time retrieved by a second qubit at the other end.
One of two papers that demonstrate the communication of individual quantum states between superconducting qubits via a quantum bus. This quantum bus is a resonant cavity formed by a superconducting transmission line of several millimetres. Quantum information, initially defined in one qubit on one end, can be stored in this quantum bus and at a later time retrieved by a second qubit at the other end.
When high pressures are applied, crystals of lithium and sodium undergo a sequence of phase transitions, including a striking pressure-induced drop in the melting temperature. The cause of the unusual melting behaviour has now been identified: it emerges because liquid sodium undergoes a series of transitions similar to those seen in the solid state, but at much lower pressures. One of these transitions is driven by the opening of a 'pseudogap' in the electronic density of states.
Oxygen isotope records from stalagmites in Northern Borneo reflect changes in tropical Pacific hydrology on millennial timescales over the past 27,000 years. The records indicate that the tropical Pacific hydrological cycle is sensitive to high-latitude climate processes in both hemispheres, as well as to external radiative forcing, and that it may have played an important role in abrupt climate change events.
High-pressure experiments are used to show that large parts of the Earth's asthenosphere are metal-saturated, demonstrating that oxidation is only a shallow phenomenon restricted to an upper veneer only about 250 km depth.
Detailed evidence from the earliest known Neolithic site in eastern China, around 7,700 years ago, demonstrates that Neolithic communities selected lowland swamps for their rice cultivation. The results establish that rice cultivation began in coastal wetlands of eastern China, an ecosystem vulnerable to coastal change but of high fertility and productivity, attractions maximised for about two centuries by sustained high levels of cultural management of the environment.
A French and Italian consortium has produced sequence and analysis of Vitis vinifera PN40024, a grapevine originally derived from Pinot Noir. As you might expect, the grapevine has twice as many terpene synthases as other sequenced plants; these enzymes contribute to resins, essential oils and aromas.
In humans, there is considerable variation between individuals in their sensitivity to certain smells and their subjective experience of them. This paper identifies a potential genetic source of variability in perception of odorous steroids. OR7D4, an odorant receptor, is selectively activated in vitro by androstenone and variants of the gene are associated with differences in psychophysical performance in human subjects
Pax5 is a transcription factor important for B cell differentiation and function. Deletion of Pax5 in mature B cells causes them to de-differentiate to less differentiated progenitor cells that can give rise to T cells, demonstrating an unanticipated degree of developmental plasticity in this lineage.
Programmed DNA breaks are made and repaired at two points during the development of antibody-producing B cells. While the breaks occurring during V(D)J recombination utilize factors that promote non-homologous end joining, this study finds that breaks that happen during class switch recombination require only a subset of these factors, suggesting that there are other as-yet-unrecognized proteins that function in this process.
In the process of generating antibody diversity, DNA in the V(D)J locus undergoes programmed double-strand breaks that are made by the Rag1–Rag 2 complex. These breaks are repaired by the non-homologous end-joining (NHEJ) pathway. Cells deficient in NHEJ factors show very low levels of recombinants, so it was believed there might be another repair pathway. But this paper shows that an alternative NHEJ pathway exists, and that it functions at low levels even in wild-type cells.
Crystal structures of the amino-terminal four immunoglobulin domains of two Dscam isoforms, coupled with biochemical analysis, reveals a horseshoe-shaped configuration and an epitope that confers homophilic dimerization specificity of Dscam receptors.
AMP-activated protein kinase is a central regulator of energy homeostasis in mammals, and the Saccharomyces cerevisiae homologue SNF1 is essential for responses to nutrient starvation. This structure reveals features such as the ligand-binding site in the γ-subunit, the carbohydrate-binding domain in the β-subunit and a regulatory sequence in the α-subunit.
AMP-activated protein kinase (AMPK) is a central regulator of energy homeostasis in mammals. This crystal structure of the trimeric regulatory fragment of mammalian AMPK reveals the modes of AMP and ATP binding.
