The sources of sodium escaping from Io revealed by spectral high definition imaging

On Jupiter's moon Io, volcanic plumes and evaporating lava flows provide hot gases to form an atmosphere that is subsequently ionized. Some of Io's plasma is captured by the planet's strong magnetic field to form a co-rotating torus at Io's distance; the remaining ions and electrons form Io's ionosphere. The torus and ionosphere are also depleted by three time-variable processes that produce a banana-shaped cloud orbiting with Io, a giant nebula extending out to about 500 Jupiter radii, and a jet close to Io. No spatial constraints exist for the sources of the first two; they have been inferred only from modelling the patterns seen in the trace gas sodium observed far from Io. Here we report observations that reveal a spatially confined stream that ejects sodium only from the wake of the Io-torus interaction, together with a visually distinct, spherically symmetrical outflow region arising from atmospheric sputtering. The spatial extent of the ionospheric wake that feeds the stream is more than twice that observed by the Galileo spacecraft and modelled successfully. This implies considerable variability, and therefore the need for additional modelling of volcanically-driven, episodic states of the great jovian nebula.     

Overview of bat species reported in Albania with the first country records for eight species

The bat fauna of Albania, a country located in a Balkan glacial refugium and a Mediterranean biodiversity hotspot, has remained poorly studied although as many as 21 species and representatives of three species complexes had been reported before 2003. It was expected that several new species would be added to the country’s list of fauna, not only due to their occurrence in adjacent regions but to the splitting of already known taxa into sibling species and the discovery of new, cryptic species. Altogether, we recorded 32 bat species in Albania, including all of those previously reported (21) and 11 new species for the country, as a result of field work conducted in 2003–2012. Here, we report on eight bat species including Rhinolophus mehelyi, Nyctalus lasiopterus, Plecotus kolombatovici, Barbastella barbastellus, Myotis brandtii that had not been reported previously in Albania while three species (Pipistrellus pipistrellus, Plecotus austriacus, Myotis mystacinus) had been reported before changes to their taxonomy and so could be treated only as representatives of a particular species complex (i.e. sensu lato). We greatly extended the known geographic ranges of five species in the south of Europe.     

Bayesian integration in sensorimotor learning

When we learn a new motor skill, such as playing an approaching tennis ball, both our sensors and the task possess variability. Our sensors provide imperfect information about the ball's velocity, so we can only estimate it. Combining information from multiple modalities can reduce the error in this estimate. On a longer time scale, not all velocities are a priori equally probable, and over the course of a match there will be a probability distribution of velocities. According to bayesian theory, an optimal estimate results from combining information about the distribution of velocities-the prior-with evidence from sensory feedback. As uncertainty increases, when playing in fog or at dusk, the system should increasingly rely on prior knowledge. To use a bayesian strategy, the brain would need to represent the prior distribution and the level of uncertainty in the sensory feedback. Here we control the statistical variations of a new sensorimotor task and manipulate the uncertainty of the sensory feedback. We show that subjects internally represent both the statistical distribution of the task and their sensory uncertainty, combining them in a manner consistent with a performance-optimizing bayesian process. The central nervous system therefore employs probabilistic models during sensorimotor learning.     

Genetic analysis of the mouse brain proteome

Proteome analysis is a fundamental step in systematic functional genomics. Here we have resolved 8,767 proteins from the mouse brain proteome by large-gel two-dimensional electrophoresis. We detected 1,324 polymorphic proteins from the European collaborative interspecific backcross. Of these, we mapped 665 proteins genetically and identified 466 proteins by mass spectrometry. Qualitatively polymorphic proteins, to 96%, reflect changes in conformation and/or mass. Quantitatively polymorphic proteins show a high frequency (73%) of allele-specific transmission in codominant heterozygotes. Variations in protein isoforms and protein quantity often mapped to chromosomal positions different from that of the structural gene, indicating that single proteins may act as polygenic traits. Genetic analysis of proteomes may detect the types of polymorphism that are most relevant in disease-association studies.     

Sirtuin activators mimic caloric restriction and delay ageing in metazoans

Caloric restriction extends lifespan in numerous species. In the budding yeast Saccharomyces cerevisiae this effect requires Sir2 (ref. 1), a member of the sirtuin family of NAD+-dependent deacetylases. Sirtuin activating compounds (STACs) can promote the survival of human cells and extend the replicative lifespan of yeast. Here we show that resveratrol and other STACs activate sirtuins from Caenorhabditis elegans and Drosophila melanogaster, and extend the lifespan of these animals without reducing fecundity. Lifespan extension is dependent on functional Sir2, and is not observed when nutrients are restricted. Together these data indicate that STACs slow metazoan ageing by mechanisms that may be related to caloric restriction.     

Nuclear reprogramming and pluripotency

The cloning of mammals from differentiated donor cells has refuted the old dogma that development is an irreversible process. It has demonstrated that the oocyte can reprogramme an adult nucleus into an embryonic state that can direct development of a new organism. The prospect of deriving patient-specific embryonic stem cells by nuclear transfer underscores the potential use of this technology in regenerative medicine. The future challenge will be to study alternatives to nuclear transfer in order to recapitulate reprogramming in a Petri dish without the use of oocytes.     

Genomic analysis of increased host immune and cell death responses induced by 1918 influenza virus

The influenza pandemic of 1918-19 was responsible for about 50 million deaths worldwide. Modern histopathological analysis of autopsy samples from human influenza cases from 1918 revealed significant damage to the lungs with acute, focal bronchitis and alveolitis associated with massive pulmonary oedema, haemorrhage and rapid destruction of the respiratory epithelium. The contribution of the host immune response leading to this severe pathology remains largely unknown. Here we show, in a comprehensive analysis of the global host response induced by the 1918 influenza virus, that mice infected with the reconstructed 1918 influenza virus displayed an increased and accelerated activation of host immune response genes associated with severe pulmonary pathology. We found that mice infected with a virus containing all eight genes from the pandemic virus showed marked activation of pro-inflammatory and cell-death pathways by 24 h after infection that remained unabated until death on day 5. This was in contrast with smaller host immune responses as measured at the genomic level, accompanied by less severe disease pathology and delays in death in mice infected with influenza viruses containing only subsets of 1918 genes. The results indicate a cooperative interaction between the 1918 influenza genes and show that study of the virulence of the 1918 influenza virus requires the use of the fully reconstructed virus. With recent concerns about the introduction of highly pathogenic avian influenza viruses into humans and their potential to cause a worldwide pandemic with disastrous health and economic consequences, a comprehensive understanding of the global host response to the 1918 virus is crucial. Moreover, understanding the contribution of host immune responses to virulent influenza virus infections is an important starting point for the identification of prognostic indicators and the development of novel antiviral therapies.     

Association of cadherin 23 with polygenic inheritance and genetic modification of sensorineural hearing loss

Age-related hearing loss (AHL) in common inbred mouse strains is a genetically complex quantitative trait. We found a synonymous single-nucleotide polymorphism in exon 7 of Cdh23 that shows significant association with AHL and the deafness modifier mdfw (modifer of deafwaddler). The hypomorphic Cdh23(753A) allele causes in-frame skipping of exon 7. Altered adhesion or reduced stability of CDH23 may confer susceptibility to AHL. Homozygosity at Cdh23(753A) or in combination with heterogeneous secondary factors is a primary determinant of AHL in mice.     

Small molecule activators of sirtuins extend Saccharomyces cerevisiae lifespan

In diverse organisms, calorie restriction slows the pace of ageing and increases maximum lifespan. In the budding yeast Saccharomyces cerevisiae, calorie restriction extends lifespan by increasing the activity of Sir2 (ref. 1), a member of the conserved sirtuin family of NAD(+)-dependent protein deacetylases. Included in this family are SIR-2.1, a Caenorhabditis elegans enzyme that regulates lifespan, and SIRT1, a human deacetylase that promotes cell survival by negatively regulating the p53 tumour suppressor. Here we report the discovery of three classes of small molecules that activate sirtuins. We show that the potent activator resveratrol, a polyphenol found in red wine, lowers the Michaelis constant of SIRT1 for both the acetylated substrate and NAD(+), and increases cell survival by stimulating SIRT1-dependent deacetylation of p53. In yeast, resveratrol mimics calorie restriction by stimulating Sir2, increasing DNA stability and extending lifespan by 70%. We discuss possible evolutionary origins of this phenomenon and suggest new lines of research into the therapeutic use of sirtuin activators.