Crossing the Midline Roles and Regulation of Robo Receptors

AbstractIn the Drosophila CNS, the midline repellent Slit acts at short range through its receptor Robo to control midline crossing. Longitudinal axons express high levels of Robo and avoid the midline; commissural axons that cross the midline express only low levels of Robo. Robo levels are in turn regulated by Comm. Here, we show that the Slit receptors Robo2 and Robo3 ensure the fidelity of this crossing decision: rare crossing errors occur in both robo2 and robo3 single mutants. In addition, low levels of either Robo or Robo2 are required to drive commissural axons through the midline: only in robo,robo2 double mutants do axons linger at the midline as they do in slit mutants. Robo2 and Robo3 levels are also tightly regulated, most likely by a mechanism similar to but distinct from the regulation of Robo by Comm

Animal source foods and nutrition in vulnerable populations in developing countries

Malnutrition is widespread in developing countries, especially amongst women of childbearing age, infants and young children. Over the past decades, malnutrition has been shown to be caused primarily by a deficiency in micronutrients (vitamins and minerals) rather than in protein and energy. More than two billion people are suffering from such deficiencies, which are responsible for 10% of child deaths. The prevention of micronutrient deficiencies requires a balanced diet with an adequate supply of bioavailable micronutrients. Foods of animal origin have a higher and more bioavailable micronutrient content than plant foods, but their consumption is low amongst the most vulnerable populations. The current challenge is therefore to improve the quality of the diet of these populations by increasing the availability and consumption of animal source foods, taking into account the potential negative effects of an overconsumption of saturated fatsLa sous-nutrition est très prévalente dans les populations du Sud, principalement chez les femmes en âge de procréer, les nourrissons et les jeunes enfants. Il est apparu au cours des dernières décennies que, plus que les carences en protéines et énergie, la sous-nutrition est due principalement à une carence en micronutriments (vitamines et minéraux). Plus de deux milliards de personnes souffrent de ces carences qui sont responsables de 10% des décès d’enfants. Leur prévention exige des régimes équilibrés avec un contenu adéquat en micronutriments biodisponibles. Les aliments d’origine animale peuvent fournir des micronutriments en quantité plus importante et plus biodisponibles que les aliments d’origine végétale, mais leur consommation est faible dans les populations les plus vulnérables. Le défi actuel consiste donc à améliorer la qualité de l’alimentation de ces populations en augmentant la disponibilité et la consommation d’aliments d’origine animale, tout en tenant compte de l’effet négatif potentiel d’une surconsommation de graisses saturée

Analyse d'impact ex post de trente ans de recherche et développement sur les conditions de pré-abattage des ruminants

Cette analyse d’impact ex post démarre en 1984 et porte donc sur plus de 30 ans de travaux de R&D conduits par Idele et ses partenaires (MSA, DGAL, DGER, Interbev, INRAE, ADIV) sur les conditions de pré-abattage. Elle a été mise en œuvre par les méthodes ASIRPA et ImpresS. Ce cas concret a confirmé l’intérêt et l’applicabilité de ces méthodes, mais elles ont nécessité des adaptations, i) en renforçant la caractérisation des « bénéficiaires » directs comme indirects et ii) en confortant la structure du « récit d’impact ». Les connaissances opérationnelles destinées aux bouviers d'abattoirs et aux chauffeurs de camions transportant des animaux vivants, ont été valorisées sous forme i) de guides de bonnes pratiques et formations à la manipulation des animaux ; ii) de références pour la rénovation des bâtiments, utiles pour le plan de modernisation des abattoirs ; et iii) de spécifications pour l'aménagement des camions destinés au transport du bétail. Contribuant à l’élaboration de nouvelles réglementations sur le transport des animaux vivants, elles ont accompagné la mise en œuvre du règlement sur la protection animale dans les abattoirs. Ce déploiement a contribué à l’amélioration des bâtiments et des équipements de la zone de pré-abattage, mais aussi à l'appropriation de connaissances permettant aux bouviers de réduire les facteurs de stress liés à la manipulation. Les principaux impacts observables sont i) une contribution à la réduction des accidents (humains et animaux) ; ii) une meilleure rémunération des éleveurs ; iii) une amélioration de la qualité de la viande ; et iv) une contribution à construire un argumentaire de nature à rassurer les consommateurs

Functional ADA Polymorphism Increases Sleep Depth and Reduces Vigilant Attention in Humans

Homeostatically regulated slow-wave oscillations in non-rapid eye movement (REM) sleep may reflect synaptic changes across the sleep-wake continuum and the restorative function of sleep. The nonsynonymous c.22G>A polymorphism (rs73598374) of adenosine deaminase (ADA) reduces the conversion of adenosine to inosine and predicts baseline differences in sleep slow-wave oscillations. We hypothesized that this polymorphism affects cognitive functions, and investigated whether it modulates electroencephalogram (EEG), behavioral, subjective, and biochemical responses to sleep deprivation. Attention, learning, memory, and executive functioning were quantified in healthy adults. Right-handed carriers of the variant allele (G/A genotype, n = 29) performed worse on the d2 attention task than G/G homozygotes (n = 191). To test whether this difference reflects elevated homeostatic sleep pressure, sleep and sleep EEG before and after sleep deprivation were studied in 2 prospectively matched groups of G/A and G/G genotype subjects. Deep sleep and EEG 0.75- to 1.5-Hz oscillations in non-REM sleep were significantly higher in G/A than in G/G genotype. Moreover, attention and vigor were reduced, whereas waking EEG alpha activity (8.5-12 Hz), sleepiness, fatigue, and α-amylase in saliva were enhanced. These convergent data demonstrate that genetic reduction of ADA activity elevates sleep pressure and plays a key role in sleep and waking quality in human

Impact of three different TiO2 morphologies on hydrogen evolution by methanol assisted water splitting: Nanoparticles, nanotubes and aerogels

International audienceIncreasing the activity of a photocatalyst goes through the improvement of both its absorption (light) and adsorption (reactant) properties. For a given semiconducting material, the charge carrier separation is also a very important step. Properly combining chosen phases is one option to improve this separation (example of the commercial P25) and depositing platinum on the surface of the catalyst, another one. In some cases, coupling both may nevertheless lead to a decrease of photoactivity or at least limit the potentiality of the catalyst. A third option, consisting in modifying the morphology of the photoactive phase, has shown very promising results. In this study, we have elaborated, characterized and evaluated the hydrogen evolution potentiality (through methanol assisted water splitting) of different TiO2 morphologies: nanoparticles, nanotubes and aerogels. These materials have shown different behaviours depending on both their composition and morphology. Different types of separation processes have been claimed to account for the observed different photoactivities, with more or less pronounced synergetic effects, due to: the use of Pt as a co-catalyst, the mixture of different TiO2 phases (anatase and TiO2(B) or rutile) and the specific morphology of the samples (nanotubes or aerogels). Among all the tested samples, the TiO2 aerogel supported Pt one exhibited very promising performances, three times as active as P25 supported Pt, which is already much more active than pure P25 in our testing conditions