A new family of diverse skin peptides from the microhylid frog genus phrynomantis

A wide range of frogs produce skin poisons composed of bioactive peptides for defence against pathogens, parasites and predators. While several frog families have been thoroughly screened for skin-secreted peptides, others, like the Microhylidae, have remained mostly unexplored. Previous studies of microhylids found no evidence of peptide secretion, suggesting that this defence adaptation was evolutionarily lost. We conducted transcriptome analyses of the skins of Phrynomantis bifasciatus and Phrynomantis microps, two African microhylid species long suspected to be poisonous. Our analyses reveal 17 evolutionary related transcripts that diversified from to those of cytolytic peptides found in other frog families. The 19 peptides predicted to be processed from these transcripts, named phrynomantins, show a striking structural diversity that is distinct from any previously identified frog skin peptide. Functional analyses of five phrynomantins confirm the loss of a cytolytic function and the absence of insecticidal or proinflammatory activity, suggesting that they represent an evolutionary transition to a new, yet unknown function. Our study shows that peptides have been retained in the defence poison of at least one microhylid lineage and encourages research on similarly understudied taxa to further elucidate the diversity and evolution of skin defence molecules

NIKEL: Electronics and data acquisition for kilopixels kinetic inductance camera

A prototype of digital frequency multiplexing electronics allowing the real time monitoring of microwave kinetic inductance detector (MKIDs) arrays for mm-wave astronomy has been developed. Thanks to the frequency multiplexing, it can monitor simultaneously 400 pixels over a 500 MHz bandwidth and requires only two coaxial cables for instrumenting such a large array. The chosen solution and the performances achieved are presented in this paper.Comment: 21 pages, 14 figure

Interrelations cultures-élevage dans les systèmes de polyculture élevage : Quelles capacités adaptatives à différents pas de temps pour accroître l’autonomie fourragère?

Les systèmes de polyculture -élevage font l’objet d’une nouvelle reconnaissance à l’échelle internationale en termes de durabilité des exploitations et des paysages; pourtant, ils continuent de diminuer en France. Notre question de recherche concerne les changements mis en œuvre par les agriculteurs pour accroître la durabilité de leur exploitation et suppose l’observation des interrelations entre cultures et élevage, qui joue ont un grand rôle sur les bénéfices obtenus. En mobilisant le cadre d’analyse des capacités adaptatives à différentes échelles de temps des systèmes d’élevage, nous mettons en évidence différentes modalités d’interrelations entre cultures et élevage. Sur le long terme, nous constatons les effets opposés des différentes politiques publiques, notamment européennes, sur les systèmes de polyculture élevage. A moyen terme, les transitions réalisées par les agriculteurs renvoient à une plus grande finesse de la gestion à réaliser, faisant parfois appel à un référentiel de pensée différent. A moyen et court terme, les agriculteurs jouent sur la flexibilité de leur système pour qu’il s’adapte à des circonstances nouvelles de manière appropriée

Les interrelations entre cultures et élevage dans les systèmes de polyculture-élevage : quelles capacités adaptatives à différents pas de temps?

Les tendances à la spécialisation et à l’intensification des exploitations agricoles dans le but de produire toujours davantage sont observées depuis les années 60. Pourtant, ces systèmes spécialisés sont dénoncés par de nombreux auteurs (Russelle et al., 2007) pour des raisons environnementales ou économiques et les systèmes de polyculture- élevage font l'objet d'une nouvelle reconnaissance en termes de durabilité des exploitations et des paysages (Herrero et al., 2010) : échanges pailles - fumier, économies de gammes sont notamment bénéfiques pour les systèmes et le milieu

Galactic Outflows and Evolution of the Interstellar Medium

We present a model to self-consistently describe the joint evolution of starburst galaxies and the galactic wind resulting from this evolution. We combine the population synthesis code Starburst99 with a semi-analytical model of galactic outflows and a model for the distribution and abundances of chemical elements inside the outflows. Starting with a galaxy mass, formation redshift, and adopting a particular form for the star formation rate, we describe the evolution of the stellar populations in the galaxy, the evolution of the metallicity and chemical composition of the interstellar medium (ISM), the propagation of the galactic wind, and the metal-enrichment of the intergalactic medium (IGM). In this paper, we study the properties of the model, by varying the mass of the galaxy, the star formation rate, and the efficiency of star formation. Our main results are the following: (1) For a given star formation efficiency f*, a more extended period of active star formation tends to produce a galactic wind that reaches a larger extent. If f* is sufficiently large, the energy deposited by the stars completely expels the ISM. Eventually, the ISM is being replenished by mass loss from supernovae and stellar winds. (2) For galaxies with masses above 10^11 Msun, the material ejected in the IGM always falls back onto the galaxy. Hence lower-mass galaxies are the ones responsible for enriching the IGM. (3) Stellar winds play a minor role in the dynamical evolution of the galactic wind, because their energy input is small compared to supernovae. However, they contribute significantly to the chemical composition of the galactic wind. We conclude that the history of the ISM enrichment plays a determinant role in the chemical composition and extent of the galactic wind, and therefore its ability to enrich the IGM.Comment: 17 pages, 14 color figures. Accepted for publication in MNRA

Role of Kv1 Potassium Channels in Regulating Dopamine Release and Presynaptic D2 Receptor Function

Dopamine (DA) release in the CNS is critical for motor control and motivated behaviors. Dysfunction of its regulation is thought to be implicated in drug abuse and in diseases such as schizophrenia and Parkinson's. Although various potassium channels located in the somatodendritic compartment of DA neurons such as G-protein-gated inward rectifying potassium channels (GIRK) have been shown to regulate cell firing and DA release, little is presently known about the role of potassium channels localized in the axon terminals of these neurons. Here we used fast-scan cyclic voltammetry to study electrically-evoked DA release in rat dorsal striatal brain slices. We find that although G-protein-gated inward rectifying (GIRK) and ATP-gated (KATP) potassium channels play only a minor role, voltage-gated potassium channels of the Kv1 family play a major role in regulating DA release. The use of Kv subtype-selective blockers confirmed a role for Kv1.2, 1.3 and 1.6, but not Kv1.1, 3.1, 3.2, 3.4 and 4.2. Interestingly, Kv1 blockers also reduced the ability of quinpirole, a D2 receptor agonist, to inhibit evoked DA overflow, thus suggesting that Kv1 channels also regulate presynaptic D2 receptor function. Our work identifies Kv1 potassium channels as key regulators of DA release in the striatum

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Do labour productivity and preferences about work load distribution affect reproduction management and performance in pig farms

Increases in labour productivity are essential factors, as well as technical effectiveness, for the competitiveness of pig farming. However, the preferences of farmers for controlled (i.e. limited) daily working hours or available days for vacation also increase. The objective of this study was to explore how these preferences about work might be associated to specific combinations of practices or affect performance. The study was carried out by direct investigation of the stockbreeders. Data analysis used factorial analysis to identify relationships between practices, labour productivity, sow productivity and work load distribution. Results showed independence between sow productivity and labour productivity. Three independent types of preferences about work load distribution were identified: the limitation of density of daily work, the avoidance of insemination activities during the weekend and the avoidance of far rowing supervision during the weekend. These preferences about work load distribution were mainly related to weaning, oestrus detection and insemination techniques. A relationship was also seen between far rowing and cross fostering techniques, and labour and sow productivity. Results suggest that preferences about work load distribution influence the choice of reproduction practices without influencing performance. Finally, concerning the labour productivity, it was linked with some specific techniques at far rowing but the results also indicated that it was mainly related to the size of far rowing batches

Quelles attentes des éleveurs de truies vis-à-vis du rythme de travail intra-hebdomadaire et quels liens avec les pratiques d’élevage ?

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