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Researchers have rallied round a promising molecule for rescuing dying nerves. But getting it into the brain remains a daunting challenge, finds Brian Vastag.
A bold attempt to tell the complicated story behind the human DNA sequence highlights that social change is needed before personalized medicine can take off, finds Jan Witkowski.
Vannevar Bush's pivotal report that marked the beginning of modern science policy catapulted the phrase 'basic research' into popular usage, explains Roger Pielke Jr.
Air pollution can cause a widespread haze in the Arctic. A study of the lower atmosphere there suggests that haze particles might take up free radicals, and so extend the lifetime of air pollutants in the region.
Different versions of the same gene can be either dominant or recessive. A small non-coding RNA mediates such differences in dominance as part of a system that prevents inbreeding in plants.
Waves have been discovered in the molecular cloud surrounding the Orion nebula, generated by shearing flows in the cloud. This finding provides clues to the way filamentary substructures form in the interstellar medium.
The protein OTUB1 inhibits DNA repair without using its enzymatic activity. Instead, it sequesters a protein that is required for the assembly of certain forms of ubiquitin chain, which function as key signals during repair.
Help from earlier offspring in rearing a subsequent brood should evolve more easily when the mother is strictly monogamous. A comparative study of birds provides evidence in support of this view.
A puzzling case is presented by the occurrence of two large but dissimilar earthquakes at almost the same time and place. One must have acted as the trigger, but which one and how did it do so?
Enzymes that move along DNA, such as DNA and RNA polymerases, cause the DNA ahead of them to become supercoiled. This would lead to the DNA becoming overwound, were the stress not relieved by topoisomerases. Topoisomerase inhibitors have been used as antibacterial and anticancer drugs, but the structural basis for their activity has been unclear. Here, the crystal structures are presented of a topoisomerase on DNA, either alone or in the presence of a new type of antibiotic.
When double-strand breaks occur in eukaryotic DNA, the chromatin that protects and organizes the genome must be removed from the vicinity of the break to allow repair factors to bind. Such chromatin displacement involves the addition of ubiquitin groups to histone proteins near the break by the ubiquitin ligases RNF8 and RNF168. Here it is shown that the enzyme OTUB1 prevents RNF168-dependent poly-ubiquitination. Pharmacological targeting of this process might enhance the DNA damage response.
It has long been suspected that the development of hydrodynamical instabilities can compress or fragment a molecular cloud (in which stars are born). One key signature of an instability would be a wave-like structure in the gas, although this has not yet been seen. Now, the presence of 'waves' is reported at the surface of the Orion cloud, near where massive stars are forming. The waves probably arise as gas that is heated and ionized by massive stars is blown over pre-existing molecular gas.
The superconducting phase of a superconductor is often one of several competing types of electronic order, including antiferromagnetism and charge density waves. For some superconductors, the superconducting transition temperature can be maximized by forcing the critical temperature of the competing order down to zero. Now, a related effect has been identified in a high-temperature superconductor, with the application of pressure yielding a striking two-step increase in the transition temperature.
Ferroelectric ferromagnets — materials that are both ferroelectric and ferromagnetic — are of significant technological interest. But they are rare, and those that do exist have weak ferroelectric and ferromagnetic properties. Recently a new way of fabricating such materials was proposed, involving strain from the underlying substrate. This route has now been realized experimentally for EuTiO3. The work shows that a single experimental parameter, strain, can simultaneously control multiple order parameters.
On 29 September 2009, a tsunami devastated the Samoan and northern Tongan islands. It is shown here that an unusual earthquake sequence preceded this tsunami. A magnitude-8 earthquake in the outer-rise intraplate region occurred almost simultaneously with rupture of the shallow subduction interplate interface, equivalent to a magnitude-8 earthquake. The findings provide information on strain release mechanisms at subduction zones, and a possible mechanism for the occasional large tsunamis generated at the Tonga subduction zone.
On 29 September 2009, a tsunami devastated the Samoan and northern Tongan islands. Here, an unusual earthquake sequence that preceded this tsunami is analysed. A magnitude-8.1 intraplate faulting event in the outer trench-slope at the northern end of the Tongan subduction zone was followed by extensive interplate faulting, with total moment equivalent to that of a magnitude-8.0 earthquake. Overlap of the seismic signals had obscured the fact that distinct faults had ruptured with different geometries.
A phylogenetic analysis of breeding behaviour in birds shows that cooperation is more likely when promiscuity is low — a circumstance in which helpers can be more certain that they are offering aid to relatives. Intermediate levels of promiscuity favour the ability to distinguish relatives from non-relatives. At high levels of promiscuity, no form of cooperation is favoured. Levels of promiscuity therefore provide an explanation for differences between species in levels of cooperation.
Here, the human immune response to infection with Mycobacterium tuberculosis has been characterized by transcriptional profiling. The results show that active tuberculosis correlates with a particular transcriptional signature that is dominated by a neutrophil-driven interferon-inducible gene profile. The study provides a broad range of transcriptional biomarkers with potential as diagnostic and prognostic tools to combat the tuberculosis epidemic.
The thymus contains thymic epithelial cells (TECs), which form a complex three-dimensional network organized into cortical and medullary compartments. It is shown here that these cells are plastic. Clonogenic TECs can acquire new properties when exposed to the skin microenvironment; under such conditions, they can permanently adopt the fate of hair follicle multipotent stem cells. Hence, microenvironmental cues can be sufficient to re-direct epithelial cell fate.
A diploid organism has two copies of each gene, one inherited from each parent. The expression levels of the two alleles can be biased by dominant/recessive relationships. In Brassica, self-incompatibility in pollen is determined by dominance relationships between the two alleles of the gene SP11; the recessive allele is methylated and hence silenced. Here it is shown that such methylation is controlled by a small non-coding RNA encoded in the flanking region of the dominant allele.
DNA replication occurs only once per cell cycle, and numerous pathways prevent re-replication. Here it is shown that mutations in ARABIDOPSIS TRITHORAX-RELATED PROTEIN5 (ATXR5) and ATXR6 — which encode histone methyltransferases — lead to re-replication of specific genomic locations, notably those corresponding to transposons and other repetitive and silenced elements. ATXR5 and ATXR6 are proposed to be components of a pathway that prevents over-replication of heterochromatin in Arabidopsis.
Here, a new type of behaviour of receptor–ligand bonds has been identified, by using a new method that links receptor and ligand in a single molecule to measure binding and unbinding. The binding of von Willebrand factor to the glycoprotein Ib α subunit on the surface of platelets is important for coagulation. This receptor–ligand bond is now shown to have two distinct states, one seen at low force and a second that has greater force resistance. This has implications for how increased blood flow activates platelet plug formation.
The bacterial flagellar motor drives the rotation of flagellar filaments, propelling bacteria through viscous media. The rotation can switch from an anticlockwise to a clockwise direction, determining a smooth or tumbling motion. A protein called FliG forms a ring in the motor's rotor, and has been proposed to adopt distinct conformations that induce switching. Here, the full-length structure of FliG is presented, and conformational changes are identified that are involved in switching between clockwise and anticlockwise rotations.
Propionyl-coenzyme A carboxylase (PCC) is a biotin-dependent enzyme that is essential for the catabolism of several amino acids, cholesterol and some fatty acids. Here, the crystal structure of a bacterial PCC is presented, along with a cryo-electron microscopy reconstruction showing a similar structure for human PCC. The structural information establishes a molecular basis for understanding the known disease-causing mutations in PCC, and is relevant to the holoenzymes of other biotin-dependent carboxylases.
Stefania Mondello, a postdoc at the University of Florida, received the 2010 Premio Award, presented to outstanding female Italian scientists working in North America, at the annual conference of the Italian Association for Women Inventors and Innovators in Bari, Italy, in June.
Comparative-effectiveness research answers questions that could transform medical policy and practice. Tamar Nordenberg examines the opportunities for researchers to find both funding and fulfilment.
