Fluorescent nanodiamond tracking reveals intraneuronal transport abnormalities induced by brain-disease-related genetic risk factors

Brain diseases such as autism and Alzheimer's disease (each inflicting >1% of the world population) involve a large network of genes displaying subtle changes in their expression. Abnormalities in intraneuronal transport have been linked to genetic risk factors found in patients, suggesting the relevance of measuring this key biological process. However, current techniques are not sensitive enough to detect minor abnormalities. Here we report a sensitive method to measure the changes in intraneuronal transport induced by brain-disease-related genetic risk factors using fluorescent nanodiamonds (FNDs). We show that the high brightness, photostability and absence of cytotoxicity allow FNDs to be tracked inside the branches of dissociated neurons with a spatial resolution of 12 nm and a temporal resolution of 50 ms. As proof of principle, we applied the FND tracking assay on two transgenic mouse lines that mimic the slight changes in protein concentration ( approximately 30%) found in the brains of patients. In both cases, we show that the FND assay is sufficiently sensitive to detect these changes

Visualizing a Complete Siphoviridae Member by Single-Particle Electron Microscopy: the Structure of Lactococcal Phage TP901-1

Tailed phages are genome delivery machines exhibiting unequaled efficiency acquired over more than 3 billion years of evolution. Siphophages from the P335 and 936 families infect the Gram-positive bacterium Lactococcus lactis using receptor-binding proteins anchored to the host adsorption apparatus (baseplate). Crystallographic and electron microscopy (EM) studies have shed light on the distinct adsorption strategies used by phages of these two families, suggesting that they might also rely on different infection mechanisms. Here, we report electron microscopy reconstructions of the whole phage TP901-1 (P335 species) and propose a composite EM model of this gigantic molecular machine. Our results suggest conservation of structural proteins among tailed phages and add to the growing body of evidence pointing to a common evolutionary origin for these virions. Finally, we propose that host adsorption apparatus architectures have evolved in correlation with the nature of the receptors used during infection

Analysis of integrin dynamics by fluorescence recovery after photobleaching

Cell migration is a complex cellular behavior that involves the controlled reorganization of the link between the actin cytoskeleton and the extracellular matrix. This mechanical connection is provided by transmembrane receptors of the integrin family. Integrins are heterodimeric receptors that undergo an allosteric switch when activated by external or intracellular signals, providing binding sites for ligands of the extracellular matrix and actin-associated cytoplasmic adapter proteins. Techniques such as fluorescence recovery after photobleaching (FRAP) are used to analyze the remodeling of green fluorescent protein (GFP)-tagged integrin receptors within focal adhesions, demonstrating that the dynamics of the remodeling of integrins in substrate adhesion sites is carefully regulated by extracellular ligands, cytoskeletal adapter proteins, and the actin cytoskeleton. FRAP analysis of GFP-tagged integrins is a tool that allows one to detect and dissect the internal dynamics of apparently immobile focal adhesions, allowing one to perceive the hierarchies and mechanisms of focal adhesion formation and dispersion

Rapport final d'exécution du projet Feader - Région Guadeloupe "Plan Banane Durable 2 Guadeloupe", AAP Mesure 16.1 du PDRG-SM 2014-2020

Projet multi-partenarial par définition (Cirad, IT2, Groupements de Producteurs, Ugpban) conçu avec et pour les producteurs, ce projet Plan Banane Durable 2 Guadeloupe avait pour objectifs de : - Concevoir et développer des solutions de contrôle durable de la Cercosporiose noire en recourant de façon très limitée aux fongicides. Les leviers d'actions sont ici les effeuillages prophylactiques, la promotion des services écosystémiques dans les bananeraies, le recours à la sélection variétale et la promotion de la biodiversité. - Proposer et développer des solutions innovantes et intégrées pour le contrôle des mûrs d'arrivage et des maladies de conservation (chancre et pourritures de couronnes). - Développer et promouvoir des systèmes de culture de la banane relevant de l'Agroécologie, et de l'Agriculture biologique. - Concevoir et développer des variétés résistantes à la Cercosporiose noire qui soient adaptées à l'export sur le marché européen, en finalisant dans le même temps les itinéraires techniques de culture ou post- récolte et les tests en filière de la variété résistante Cirad 925. - Sélectionner, tester, contribuer à l'homologation de méthodes de bio-contrôle contre les maladies et ravageurs des bananiers. - Favoriser l'adoption par les agriculteurs des techniques innovantes développées, assurer leur formation et leur information. - Aider à prévenir l'arrivée en Guadeloupe de la terrible fusariose TR4 (Race 4 tropicale de la maladie de Panama qui décime les bananiers Cavendish en Asie). Ce faisant, ce projet s'inscrivait dans une volonté réaffirmée de renforcer la préservation de l'environnement et la santé des travailleurs et de la population locale, par des savoir-faire à moindre impact environnemental et sanitaire