Discovery and mapping of a new expressed sequence tag-single nucleotide polymorphism and simple sequence repeat panel for large-scale genetic studies and breeding of Theobroma cacao L.

Theobroma cacao is an economically important tree of several tropical countries. Its genetic improvement is essential to provide protection against major diseases and improve chocolate quality. We discovered and mapped new expressed sequence tag-single nucleotide polymorphism (EST-SNP) and simple sequence repeat (SSR) markers and constructed a high-density genetic map. By screening 149 650 ESTs, 5246 SNPs were detected in silico, of which 1536 corresponded to genes with a putative function, while 851 had a clear polymorphic pattern across a collection of genetic resources. In addition, 409 new SSR markers were detected on the Criollo genome. Lastly, 681 new EST-SNPs and 163 new SSRs were added to the pre-existing 418 co-dominant markers to construct a large consensus genetic map. This high-density map and the set of new genetic markers identified in this study are a milestone in cocoa genomics and for marker-assisted breeding. The data are available at http://tropgenedb.cirad.fr

Explore 2070 : quelle utilisation d’un exercice prospectif sur les impacts des changements climatiques à l’échelle nationale pour définir des stratégies d’adaptation ?

Les changements climatiques projetés à l’horizon du milieu du XXIe siècle pourraient avoir des impacts importants sur la disponibilité en eau en France. L’étude prospective Explore 2070, pilotée par le ministère chargé de l’écologie, a ainsi mis en évidence la nécessité de quantifier et d’anticiper ces changements, et de construire des stratégies d’adaptation pour limiter leurs conséquences négatives sur les hydrosystèmes et les activités humaines. Cet article analyse dans quelle mesure ces travaux ont pu contribuer à la sensibilisation des acteurs de l’eau et à la réflexion sur l’adaptation au changement climatique en France

Magnetic Resonance Elastography of Rodent Brain

International audienceMagnetic resonance elastography (MRE) is a non-invasive imaging technique, using the propagation of mechanical waves as a probe to palpate biological tissues. It consists in three main steps: production of shear waves within the tissue; encoding subsequent tissue displacement in magnetic resonance images; and extraction of mechanical parameters based on dedicated reconstruction methods. These three steps require an acoustic-frequency mechanical actuator, magnetic resonance imaging acquisition, and a post-processing tool for which no turnkey technology is available. The aim of the present review is to outline the state of the art of reported setups to investigate rodent brain mechanical properties. The impact of experimental conditions in dimensioning the setup (wavelength and amplitude of the propagated wave, spatial resolution, and signal-to-noise ratio of the acquisition) on the accuracy and precision of the extracted parameters is discussed, as well as the influence of different imaging sequences, scanners, electromagnetic coils, and reconstruction algorithms. Finally, the performance of MRE in demonstrating viscoelastic differences between structures constituting the physiological rodent brain, and the changes in brain parameters under pathological conditions, are summarized. The recently established link between biomechanical properties of the brain as obtained on MRE and structural factors assessed by histology is also studied. This review intends to give an accessible outline on how to conduct an elastography experiment, and on the potential of the technique in providing valuable information for neuroscientists

Characterization of fibril aggregates in ex vivo rat brain with multi- frequency MR Elastography -Preliminary results

International audienceFibrils are biomarkers for early stages of dementia. In this work, α-synuclein fibrils were injected in rat striatum. Brains were imaged ex-vivo using multi-frequency MR Elastography. Estimation of the real part k r of the complex wave number was made for each studied frequency in ROIs surrounding the inclusion, a contralateral control injection and the whole brain. Exponent of the frequency power law was derived from k r maps acquired at different frequencies. No difference was observed between k r values for the different ROIs, but the exponent was more important at the fibrils location, potentially indicating that multi-frequency MRE can detect fibrils

Effect of cerebral protein aggregates on tissue mechanical properties measured by Magnetic Resonance Elastography

National audienceIn several cases of neurodegenerative diseases, cerebral proteins can agglomerate and form fibrils as from the early stages of the illness [1]. The endogenous proteins involved are different depending on the disease (β-amyloid for Alzheimer’s disease, α-synuclein for Parkinson’s disease and Tau protein frontotemporal dementia), but the structure remains the same: β-sheets. Those aggregates can be detected in vivo with TEP-scan and radiotracers, but the exam is irradiating, and the response is only qualitative yet [2]. The tracers are also only designed to identify one type of aggregate at the time, which is too specific for a screening test. MRI only permits a late detection of the illness, based on a diminution of the brain volume, direct detection of the aggregates showing little sensitivity [3]. The need for a simple test that could attest the presence of a neurodegenerative illness at an early stage is thus still very strong.We propose to develop an in vivo imaging technique based on the link between the microscopic structure of the aggregates and macroscopic observables collected with an MRI device.Magnetic Resonance Elastography (MRE) consists of the study of shear wave propagation in the matter, using an MRI signal. The wave observed is produced by an exterior shaker synchronized with the MRE signal. Images are taken at different steps of the wave propagation. After appropriate reconstruction, the wave speed is obtained. It leads to the viscoelastic properties of the matter. The relation between the wave speed and the input frequency reflects the multiple diffraction in the microscopic scale [4,5], and we expect to determine the link between the fibrillary structure of the protein aggregates and the MRI signal thanks to this relation. Developments will be required to obtain an adequate image resolution. Development of 3D-printed phantoms with fibril inclusions is ongoing. Those phantoms are, in the meantime, characterized with MRE. After a full study of the received signal and characterization of the fibrils, ex vivo, and in vivo studies are scheduled. Their aim is to determine if the “micro/macro” link observed in phantoms persist in vivo, where the environment is more complex.Our study is still at the beginning of its implementation, but MRE appears like a promising way to characetrize small objects with a specific structure. We hope to develop it enough to make the idea of its clinical use practicable

Impact d’une prise en charge par hypnose sur le vécu et l’observance des recommandations hydriques en hémodialyse : résultats d’un protocole à cas unique chez deux patients

INTRODUCTION: L’hémodialyse, un des traitements principaux de l’insuffisance rénale, est associée à des recommandations hydriques souvent source de frustration, souffrance et de non-observance chez de nombreux patients. L’objectif de cette étude était d’évaluer l’effet d’une prise en charge par hypnose sur le vécu des recommandations hydriques. PATIENTS ET MÉTHODE: L’efficacité de l’hypnose a été évaluée à partir d’un protocole à cas unique de type ABA auprès de deux patients en hémodialyse. Un protocole en 3 phases de 3 semaines comprenant 3 séances d’hypnose a été réalisé. Plusieurs outils ont été utilisés en mesures répétées : le KDQoL-36 pour la qualité de vie, la Health-Specific Self-Efficacy Scales pour le sentiment d’auto-efficacité et des échelles numériques pour l’observance thérapeutique et la soif. RÉSULTATS: Quelques changements significatifs ont été constatés avec maintien des effets après l’intervention : amélioration de la qualité de vie globale pour le patient 1, amélioration du sentiment d’auto-efficacité vis-à-vis des freins pour le patient 2. L’analyse visuelle a montré des améliorations, mais sans effet significatif, telles que l’atténuation de la soif et de la gêne associée et une amélioration de l’observance perçue. CONCLUSION: Ces résultats préliminaires mettent en avant une certaine variabilité entre les sujets et l’intérêt de poursuivre la recherche en incluant davantage de patients grâce à la méthode des protocoles à cas unique.INTRODUCTION: Hemodialysis is associated with dietary and fluid restrictions, which can be a source of frustration, suffering and non-compliance in many patients. Hypnosis, a booming therapeutic tool in the health field, could improve patients’ feelings. The objective of this study is to assess the effect of hypnosis on fluid restrictions experience. METHOD: The effectiveness of the hypnotic intervention was evaluated using a single-case protocol (ABA type) with two patients. A protocol in 3 phases of 3 weeks was used with three sessions of hypnosis. Several measurement tools have been used: the KDQoL-36 for quality of life, the Health-Specific Self-Efficacy Scales (adapted for dialysis patients) for self-efficacy, and numeric scales for therapeutic compliance and thirst. RESULTS: Some significant changes were observed with maintenance of the effects after hypnosis: improvement in the global quality of life for patient 1, improvement of self-efficacy (barrier) for patient 2. The visual analysis showed improvements but without significant effect as alleviation of thirst and discomfort, improvement of perceived compliance. CONCLUSION: These preliminary results concerning the effects of hypnosis on the experience of fluid restrictions are mixed reflecting variability between patients. However, these results are encouraging and show the need to continue this evaluation with more patients thanks to the advantages of the single-case protocol method

Larval dispersal of pearl oysters Pinctada margaritifera in the Gambier Islands (French Polynesia) and exploring options for adult restocking using in situ data and numerical modelling

Black pearl farming is the second source of French Polynesia income after tourism, and Gambier Islands are the main farming sites. Gambier main lagoon contains several sub-lagoons critical for pearl oyster rearing and spat collecting (SC). The Rikitea lagoon, traditionally had good SC rates in the warm season which ensured steady supplies of oysters for black pearl production. However, since 2018, SC has abruptly decreased. To assess the factors affecting SC, Gambier lagoon hydrodynamics was investigated in 2019–2020 to calibrate a hydrodynamic model and simulate larval dispersal around the SC areas. The model shows the strong wind influence on larval dispersal and accumulation patterns and suggests that windy months in the warm season as it can occur during La Niña episodes can explain recent poor SC. Larval dispersal scenarios also informed on best locations to perform adult oyster restocking, a practice that can also enhance SC on the long term

Macromolecular Structure of Dodecyltrimethylammonium Chloride at the Silica/Water Interface Studied by Sum Frequency Generation Spectroscopy

Adsorption of the cationic surfactant dodecyltrimethylammonium chloride at the silica/water interface was studied using sum frequency generation (SFG) spectroscopy under high ionic strength (100 mM NaCl) and at pH values ranging from 3 to 11, which are conditions relevant to hydraulic fracturing in enhanced oil recovery operations. At surfactant concentrations above the critical micelle concentration, SFG spectra of the CH stretching region indicate a more noncentrosymmetric structure for the surfactant aggregate is formed at the interface under acidic or basic conditions compared to neutral conditions. The SFG spectra also indicate a change in the packing/ordering of the surfactant hydrophobic tails with pH as well. In addition, the observed changes in the SFG spectra of water upon the addition of surfactant vary depending on the pH. At pH 7 and 11, the SFG intensity decreases in the OH stretching region, indicating a decrease in the magnitude of the electrostatic potential at the interface when the cationic surfactant is adsorbed at the negatively charged silica/water interface. At pH 3, an increase in the SFG intensity in the OH stretching region is attributed to an increase in the electrostatic potential at the silica/water interface due to the adsorption of a positively charged surfactant at a pH value close to the point of zero charge for the silica surface. These results demonstrate how the pH can influence the macromolecular structure of surfactants at mineral/water interfaces through the corresponding changes in the interfacial charge density and interfacial potential. In particular, we discuss how an unequal density of surfactants on each side of the interfacial bilayer or the adsorbed micelles may exist under either acidic or basic pH conditions

Cah Nutr Diet

La maladie rénale chronique (MRC) est une maladie fréquente, pouvant évoluer de manière progressive et irréversible vers le stade où un traitement de suppléance par dialyse ou transplantation rénale s’avère nécessaire. La dénutrition est une complication fréquente de la MRC et est associée à un sur-risque d’hospitalisation et de mortalité. Une surveillance diététique par le néphrologue et/ou un diététicien doit être réalisée régulièrement quel que soit le stade de la MRC. L’évaluation doit être multiple, se basant sur les données anthropométriques, la composition corporelle, des données biologiques et des enquêtes diététiques. Dans le but de ralentir la progression de la MRC et d’améliorer la qualité de vie, chez les patients stables métaboliquement présentant une MRC de stades 3b à 5, non dialysés, les apports en protéines doivent être réduits à 0,55–0,60 g/kg/j ou 0,3–0,4 g/kg/j associée à une supplémentation en céto-analogues, sous couvert d’apports caloriques suffisants entre 25 à 35 kcal/kg/j. Chez les patients dialysés, les apports en protéines doivent en revanche être augmentés entre 1,0 et 1,2 g/kg/j avec des apports caloriques identiques entre 25 à 35 kcal/kg/j. Une supplémentation orale doit être envisagée en première intention en cas de dénutrition ou d’apports caloriques insuffisants.Chronic kidney disease (CKD) is a common condition that can progressively and irreversibly progress to a stage where renal replacement therapy by dialysis or kidney trans-plantation is required. Protein-energy wasting (PEW) is a frequent complication in CKD patients and is associated with an increased hazard of hospitalisation and mortality. Dietary monitoring by the nephrologist and/or a dietician must be conducted regularly, whatever the stage of the disease. The assessment should be multiple, based on anthropometric data, body composition, biological data and dietary surveys. In order to slow CKD progression and improve quality of life in metabolically stable patients with CKD stages 3b to 5, not on dialysis, protein intake should be reduced to 0.55-0.60 g/kg/d or 0.3-0.4 g/kg/d in combination with keto-acid ana-logs, with adequate caloric intake of 25-35 kcal/kg/d. However, in dialysis patients, protein intake should be increased to 1.0-1.2 g/kg/d with the same caloric intake of 25-35 kcal/kg/d. Oral supplementation should be considered in first intention in cases of PEW or insufficient caloric intake.(c) 2022 Societe francaise de nutrition. Published by Elsevier Masson SAS. All rights reserved

The apparent mechanical effect of isolated amyloid‐β and α‐synuclein aggregates revealed by multi‐frequency MRE

International audienceSeveral biological processes are involved in dementia, and fibrillar aggregation of misshaped endogenous proteins appears to be an early hallmark of neurodegenerative disease. A recently developed means of studying neurodegenerative diseases is magnetic resonance elastography (MRE), an imaging technique investigating the mechanical properties of tissues. Although mechanical changes associated with these diseases have been detected, the specific signal of fibrils has not yet been isolated in clinical or preclinical studies. The current study aims to exploit the fractal‐like properties of fibrils to separate them from nonaggregated proteins using a multi‐frequency MRE power law exponent in a phantom study. Two types of fibril, α‐synuclein (α‐Syn) and amyloid‐β (Aβ), and a nonaggregated protein, bovine serum albumin, used as control, were incorporated in a dedicated nondispersive agarose phantom. Elastography was performed at multiple frequencies between 400 and 1200 Hz. After 3D‐direct inversion, storage modulus (G'), phase angle (ϕ), wave speed and the power law exponent (y) were computed. No significant changes in G' and ϕ were detected. Both α‐Syn and Aβ inclusions showed significantly higher y values than control inclusions ( P = 0.005) but did not differ between each other. The current phantom study highlighted a specific biomechanical effect of α‐Syn and Aβ aggregates, which was better captured with the power law exponent derived from multi‐frequency MRE than with single frequency‐derived parameters