Articles

Aminoacyl-transfer RNA synthetases are conserved between bacteria and eukaryotes; however, bacterial enzymes cannot acylate eukaryote tRNAs. Now, fusion of a human and bacterial enzyme is shown to overcome the species barrier and confer tRNA specificity during both codon selection and proofreading on the ribosome.

Complex diseases such as multiple sclerosis have both genetic and environmental components. This study demonstrates that variants of genes implicated in multiple sclerosis, and alterations in cellular metabolism and vitamin D3 levels, alterN-glycosylation, a post-translational modification causal of the disease in mice.

Circadian rhythm is controlled by the suprachiasmatic nucleus and the mechanisms that control the rhythm are largely undiscovered. In this study, a G protein regulator, RGS16, is shown to be involved in the production of cyclic AMP that is required for the suprachiasmatic nucleus to maintain rhythm

Increasing the nutritional content of plant crops and the identification of iron transporters in rice would facilitate the improvement of rice varieties. In this study, the authors identify a mitochondrial iron transporter in rice — MIT — and suggest that this gene is important for rice growth and development.

Genomes evolve with time but the molecular mechanisms that underlie this process are poorly understood. Gontijoet al. describe a protein that was generated by the retention of an intron in the Drosophila melanogaster Rieske iron sulphur proteingene and show that the resulting protein is translated.

Phylogenetic analysis is used to identify transmission chains, but no software is available for the automated partition of large phylogenies. Prosperiet al. apply a new search algorithm to identify transmission clusters within the phylogeny of HIV-1gene sequences linking molecular and epidemiological data.

Lithium–sulphur batteries may achieve higher energy densities than conventional lithium-ion cells, but the dissolution of sulphur intermediates is a continuing challenge. Here this problem is overcome using a cathode with a mesoporous structure that is able to accommodate intermediate polysulphide anions.

Secondary metabolites are widely used in human health and nutrition, but extraction yields from plants are often low. Nakagawaet al. have engineered the metabolism of Escherichia colito develop a fermentation system that produces plant alkaloids from simple carbon sources.

The cryptic Wood White butterflies,Leptidea sinapis and Leptidea reali, represent a model for the study of speciation. Dincă et al. use DNA and chromosome data to show that this group, in fact, consists of a triplet of species, a result that provides a new perspective on cryptic biodiversity.

Two-dimensional fluid interfaces are ubiquitous, but studying their surface dynamic properties is difficult because of coupling between the film and bulk fluid. Choiet al.combine active microrheology with fluorescence microscopy to image fluid interfaces under applied stress.

The mechanisms by which animals distinguish between harsh and gentle touch are unclear. UsingCaenorhabditis elegansas a model system, the authors identify neural circuits and touch-sensitive ion channels that are required for harsh touch sensation.

Amblyopia induced by chronic monocular deprivation can be reversed by dark exposure, followed by reverse deprivation in adulthood. The authors show that dark exposure in adulthood reactivates plasticity in the visual cortex, including thalamocortical synapses, promoting recovery from deprivation amblyopia.

Global darkness from an asteroid impact 65.5 million years ago led to massive extinction of oceanic phytoplankton, but coastal groups survived. Ribeiroet al.revive coastal dinoflagellates after a century of dormancy, suggesting phytoplankton survived the extinction and helped restore photosynthesis in the ocean.

There is debate about the structural organization of the yeast centromeric nucleosome and the role of the nonhistone protein Scm3 in its assembly. Dechassaet al.find that yeast centromeric nucleosomes organize DNA in a left-handed superhelix, and show that Scm3 is a specific nucleosome assembly factor.

ADAR enzymes edit double-stranded RNA, converting adenosines to inosines, and are essential for neuronal function. Eggingtonet al. quantify edit sites in RNA using a Sanger sequencing protocol and use the resulting data to develop algorithms to predict RNA edit sites.

The molecular mechanisms that regulate T_H17 cell diversity are poorly understood. Ouyang et al. show that the transcription factor interferon regulatory factor-8 is required for T_H17-cell differentiation and that its absence increases the severity of an experimental model of colitis.

IKK kinases activate nuclear factor-κB, and the activated form of this transcription factor is found in endothelial cells in diseased tissue. In this study, mice lacking IKKβ in the endothelium are generated, and it is shown that defects in endothelial cell function are both IKK kinase activity dependent and independent.

Mitotic exit is controlled by a cell division checkpoint that prevents premature degradation of cyclin B by the anaphase-promoting complex. Saurinet al. show that Aurora B directly regulates timely establishment of this checkpoint by facilitating activation of Mps1 kinase at unattached kinetochores.

Calorie restriction has been associated with increased life span and delayed decline of memory in animals, suggesting a role in neuronal plasticity. In this study, food restriction is demonstrated to enhance plasticity in the central nervous system and trigger the recovery from ocular deprivation in adulthood.

The conductance of single-molecule junctions is affected by the structure of the molecule and how it is bound to the electrodes, which may be examined using Raman spectroscopy. Liuet al. have developed 'fishing-mode' tip-enhanced Raman spectroscopy, which allows the simultaneous determination of conductance and Raman spectra.