From Vascular Smooth Muscle Cells to Folliculogenesis: What About Vasorin?

First described in 1988, vasorin (VASN) is a transmembrane glycoprotein expressed during early mouse development, and with a less extent, in various organs and tissues (e.g., kidney, aorta, and brain) postnatally. Vasn KO mice die after 3 weeks of life from unknown cause(s). No human disease has been associated with variants of this gene so far, but VASN seems to be a potential biomarker for nephropathies and tumorigenesis. Its interactions with the TGF-β and Notch1 pathways offer the most serious assumptions regarding VASN functions. In this review, we will describe current knowledge about this glycoprotein and discuss its implication in various organ pathophysiology

Biosynthesis and Toxicological Effects of Patulin

Patulin is a toxic chemical contaminant produced by several species of mold, especially within Aspergillus, Penicillium and Byssochlamys. It is the most common mycotoxin found in apples and apple-derived products such as juice, cider, compotes and other food intended for young children. Exposure to this mycotoxin is associated with immunological, neurological and gastrointestinal outcomes. Assessment of the health risks due to patulin consumption by humans has led many countries to regulate the quantity in food. A full understanding of the molecular genetics of patulin biosynthesis is incomplete, unlike other regulated mycotoxins (aflatoxins, trichothecenes and fumonisins), although the chemical structures of patulin precursors are now known. The biosynthetic pathway consists of approximately 10 steps, as suggested by biochemical studies. Recently, a cluster of 15 genes involved in patulin biosynthesis was reported, containing characterized enzymes, a regulation factor and transporter genes. This review includes information on the current understanding of the mechanisms of patulin toxinogenesis and summarizes its toxicological effects

Caractéristiques de la micelle des caséines et stabilité des laits ( de la collecte des laits crus au stockage des lait UHT )

La déstabilisation du lait UHT au cours du stockage sous forme d un gel ou d un sédiment, peut résulter d une déstabilisation des micelles de caséines par des réactions enzymatiques ou physicochimiques. Souvent complexes et multifactorielles, pas toujours bien évaluées ni prédites par les tests de stabilité, ces déstabilisations sont une réelle problématique industrielle et scientifique. L objectif de ce travail était d étudier les relations entre les caractéristiques des micelles de caséines et la stabilité du lait. Les facteurs influençant ces relations au niveau des tests de stabilité et pour les laits soumis à la stérilisation UHT et au stockage ont été déterminés. Des analyses au niveau moléculaire, supramoléculaire et macroscopique de différents laits ont été réalisées. Dans une première partie, nous avons montré que la réponse des principaux tests de stabilité, à savoir les tests à la chaleur, à l éthanol et au phosphate, était influencée par des facteurs spécifiques correspondant aussi bien aux caractéristiques de la micelle de caséines que de son environnement physico-chimique. Aucun facteur n était trouvé commun aux trois tests et seulement cinq étaient spécifique de chacun, pourrait expliquer l absence de corrélation entre les réponses des trois tests. Le mécanisme du test au phosphate a fait l objet d une étude plus approfondie. Nous avons observé que l ajout de fortes concentrations de KH2PO4 à du lait cru écrémé modifiait les équilibres minéraux et résultait en une solubilisation préférentielle des caséines as1 puis b. Les micelles de caséines, alors déstructurées, s agrégeaient, la teneur en eau des culots d ultracentrifugation augmentait et le lait gélifiait. Ces modifications étaient quantativement plus importantes lorsque le pH du mélange était ajusté au pH du lait que lorsqu il dérivait vers des pH acidesDestabilization of UHT milk during storage in the form of a gel or a sediment can result from a casein micelles destabilization by enzymatic or physico-chemical reactions. Often complex and multifactorial, not always well evaluated and predicted by stability tests, these destabilizations are a real industrial and scientific problematic. The objective of this work was to study relationships between casein micelles characteristics and milk stability. Factors influencing these relationships at the level of stability tests and for milks submitted to UHT sterilization and storage were determined. Analyses at the molecular supramolecular and macroscopic level were realized. In a first part, we showed that the answer of the main stability tests, namely heat, ethanol and phosphate tests, was influenced by specific factors corresponding as well to casein micelles characteristics as to those of its physico-chemical environment. No factor was found common to the three tests and only five were common to two tests. This weak number of analogies between tests, probably linked to the specific mechanism of each would explain the absence of correlation between the responses of the three test. The mechanism of phosphate test was the object of a more detailed study. We observed that addition of high concentrations of KH2PO4 to raw skim milk modified mineral equilibria and resulted in a preferential solubilisation of as1- then b-caseins. Casein micelles, then destructured, aggregated the ultracentrifugation-pellet water content increased and milk gelled. These modifications were quantitatively more important when the pH of the mixture was adjused to the pH of milk than when it derived towards acid pH.RENNES-Agrocampus-CRD (352382323) / SudocSudocFranceF

Comment gérer la biomasse végétale issue des phytotechnologies ? Perceptions des opérateurs de filières de valorisation

A survey was carried out in 4 European countries to gather end-user’s perceptions of using plants from phytotechnologies in combustion and anaerobic digestion (AD). 9 actors of the wood energy sector and 11 AD platform operators from France, Germany, Austria and Sweden were interviewed. Questions related to installation, input materials, performed analyses, phytostabilization and phytoextraction. Although the majority of respondents did not know phytotechnologies, results suggested that plant biomass from phytomanaged areas could be used in AD and combustion, under certain conditions. As a potential advantage, these plants would not compete with plants grown on agricultural lands, contaminated lands being not suitable for food/feed production. Main limitations would be related to additional controls in inputs, end-products and installations that might generate additional costs. In most cases, the price of biomass from phytotechnologies was mentioned as a driver to potentially use it. Plants used in phytostabilisation were thought to be less risky and benefited from a better theoretical acceptance than those issued from phytoextraction.La production de cultures énergétiques est considérée comme une menace pour la sécurité alimentaire et le développement durable. Cependant, ces cultures peuvent s’effectuer sur des sols peu fertiles ou présentant une contamination ce qui permet d’éviter la compétition avec les sols agricoles tout en augmentant la production d’énergies renouvelables encouragée par la Directive 2009/28/EC et la restauration de ces sols grâce aux phytotechnologies. Les phytotechnologies sont des options de gestion des sols pollués basées sur l’utilisation de végétaux herbacés et ligneux souvent choisis pour être en synergie avec la microflore existante et des amendements apportés au sol. Ces techniques offrent la possibilité de produire de la biomasse renouvelable pour l’économie biobasée (ex : bioénergie, biocatalyse, biomatériaux) et d’améliorer les services écosystémiques en restaurant, par exemple, la structure, la qualité et les fonctions du sol. Les végétaux phytostabilisateurs affichent des concentrations en métaux identiques aux concentrations habituellement mesurées chez des végétaux se développant sur des sols non pollués tandis que les végétaux phytoextracteurs présentent des concentrations nettement supérieures à ces valeurs. Des essais de combustion conduits sur des saules enrichis en métaux (Cd et Zn) ont montré que leur valorisation était possible à condition que les chaudières soient équipées de filtres efficaces. Cependant, pour la combustion et la méthanisation, la possibilité d’épandre respectivement les cendres et le digestat pourrait, dans certains cas, être problématique. Elle dépend en effet de la qualité des résidus et du cadre règlementaire. La perception par les opérateurs de filières de valorisation des biomasses issues de phytotechnologies ayant été peu étudiée, une étude pour recueillir les opinions d’exploitants de chaudières à biomasse et de méthaniseurs a été réalisée. Cette étude a été conduite via des questionnaires auprès de vingt exploitants Européens issus de quatre pays (France, Allemagne, Suède et Autriche) dans le cadre du projet Greenland

Nano or Micro: 3 Different Particles to Deliver and Protect S-Nitrosoglutathione for Oral Route Administration

As a physiological nitric oxide donor, S-nitrosoglutathione (GSNO) is a promising candidate for several diseases (e.g., stroke and atherosclerosis). However, its clinical application has been limited by its low stability. In order to protect GSNO suitable for oral route administration and to achieve sustained release, 3 different particles from nano-size to micro-size were obtained by a water-in-oil-in-water (W/O/W) or solid-in-oil-in-water (S/O/W) double emulsion/solvent evaporation method. The 3 different particles tuned out to have similar encapsulation efficiency while the microparticles showed longer release time. Finally, the 3 formulations have been successfully lyophilized for long term stability

Effects of storage temperature on physico-chemical characteristics of semi-skimmed UHT milk

Storage of UHT milk results in physico-chemical changes, which can sometimes lead to aggregation or sedimentation of milk. In this study, close attention was paid to the reactions occurring in semi-skimmed UHT milk during 6 months of storage at 4, 20 and 40 1C. Overall milk characterization revealed the development of the Maillard reaction and proteolysis which led to acidification of the milk. One hundred eighty-one peptides were identified by mass spectrometry for the freshly processed UHT milk and the milks stored 6 months at 4, 20 and 40 1C. The cleavage sites gave information concerning the possible actors of proteolysis. Plasmin, cathepsins B, D and G, elastase and proteases from Pseudomonas fluorescens B52 were thus found to be potential contributors to enzymatic proteolysis. Non-enzymatic proteolysis induced by heat-treatment and storage was also observed. Despite these modifications, milk particles (casein micelles and homogenized fat globules) did not exhibit many changes in zeta-potential, except for the last storage time at 40 1C where a decrease of the absolute value of about -3mV was observed. The decrease in size in milks stored at 20 and 40 1C was only about 20nm after 6 months. Similarly, storage of UHT milk showed that the higher the storage temperature the lower the heat stability and the higher the phosphate stability. Storage leads to physico-chemical changes in milk and, although some reactions such as acidification and proteolysis are known to be destabilizing, some of them are probably stabilizing to counterbalance the negative effects

The place of natural hydrogen in the energy transition: A position paper

Natural Hydrogen is a new, clean and low-carbon source of hydrogen that is produced by the Earth, and can migrate and accumulate in geological reservoirs. Its exploration has begun in many countries and its price could be significantly lower than other H2 sources. In this position paper, the earth2 initiative summarizes (i) what natural hydrogen is, (ii) how we explore and produce it, (iii) the benefits of this new resource, (iv) the maturity of the technology, (v) the presence of a very active community (vi) the potential growth for this business, (vii) the need for regulatory evolution and appropriate taxonomy at European level and (viii) the next steps in natural H2 development, considering the needs for investments in demonstration systems and pilots

A Smooth Muscle Cell-Based Ferroptosis Model to Evaluate Iron-Chelating Molecules for Cardiovascular Disease Treatment

Dysregulation of iron homeostasis causes iron-mediated cell death, recently described as ferroptosis. Ferroptosis is reported in many chronic diseases, such as hepatic cancer, renal, and cardiovascular diseases (heart failure, atherosclerosis). However, there is a notable scarcity of research studies in the existing literature that explore treatments capable of preventing ferroptosis. Additionally, as far as the author is aware, there is currently no established model for studying ferroptosis within cardiovascular cells, which would be essential for assessing metal-chelating molecules with the potential ability to inhibit ferroptosis and their application in the treatment of cardiovascular diseases. In this study, a smooth muscle cell-based ferroptosis model is developed upon the inhibition of the system Xc− transporter by erastin associated or not with Fe(III) overload, and its rescue upon the introduction of well-known iron chelators, deferoxamine and deferiprone. We showed that erastin alone decreased the intracellular concentration of glutathione (GSH) without affecting peroxidized lipid concentrations. Erastin with ferric citrate was able to decrease intracellular GSH and induce lipid peroxidation after overnight incubation. Only deferiprone was able to rescue the cells from ferroptosis by decreasing lipid peroxidation via iron ion chelation in a 3:1 molar ratio

S-nitrosoglutathione potentiates protein S-nitrosation under oxidative stress, a potential improvement of NO storage into smooth muscle cells

Introduction To counteract NO deficiency occurring with oxidative stress (OS) in cardiovascular diseases, administration of S-nitrosothiols (RSNO) like S-nitrosoglutathione (GSNO), the main storage form of NO in tissues [1], represents an alternative to other NO-donors, with no tolerance nor OS induction. However, their ability to regulate NO bioavailability under OS is unknown. As S-nitrosation of proteins, the formation of high molecular weight RSNOs, is also considered as a form of NO storage in tissues [2], we evaluated whether an administration of GSNO will regulate protein S-nitrosation in an OS model of rat smooth muscle cells. Material and methods A rat smooth muscle cell line (SMC A-10) was stimulated by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH; 50 mM, 2 h, 37°C) to mimic OS. Intracellular thiol status as content of reduced glutathione (GSH) (2,3-naphthalene dicarboxaldehyde assay) and reduced thiol containing proteins (Ellman’s method) were monitored. The activity of γ-glutamyl transpeptidase (GGT), specifically implied in GSNO catabolism, was measured using L-γ-glutamyl-p-nitroanilide as chromogenic substrate. Then, the thiol status modifications and intracellular peptides/proteins S-nitrosation (2,3-diaminonaphthalene/Hg2+assay) were monitored in stressed SMC incubated for 1 h with 50 µM GSNO. S-nitrosated proteins were purified (biotin switch technique) and identified by mass spectrometry. Results Under OS, the intracellular content of reduced thiols was greatly decreased for GSH (59±4 to 29 ± 5 nmol/mg proteins, n = 3) compared to proteins (148 ± 6 to 125 ± 4 nmol/mg proteins, n = 3), with no impact of GSNO. However, GSNO increased the global content of intracellular S-nitrosated peptides/proteins upon OS (0.53 ± 0.04 to 1.07±0.09 nmol/mg proteins, n = 3). Although the GGT activity decreased (1.35 ± 0.20 to 0.39±0.14 nmol/min/mg proteins) under OS, it was still implied at 38±5% (using serine borate complex, a GGT specific inhibitor) into the intracellular peptides/proteins S-nitrosation. The final mass spectrometry identification revealed that 71 proteins were S-nitrosated under control condition and this rose to 93 under OS. Discussion/conclusion The increase in intracellular S-nitrosated proteins in smooth muscle cells submitted to OS and treated with GSNO can be the starting point for GSNO to restore the NO pool. How and when this NO pool can be released has to be further evaluated. References 1. Maron BA et al. Antioxid Redox Signal (2013) 18, 270-287. 2. Rayner BS et al. J Biol Chem (2005) 280, 9985-9993

Causes of variation in leaf-level drought tolerance within an Amazonian forest

International audienceAmazonian tree communities have already been seriously impacted by extreme natural droughts, and intense droughts are predicted to increase in frequency. However, our current knowledge of Amazonian tree species' responses to water stress remains limited, as plant trait databases include few drought tolerance traits, impeding the application and predictive power of models. Here we explored how leaf water potential at turgor loss point (π tlp), a determinant of leaf drought tolerance, varies with species life history, season, tree size and irradiance within a forest in French Guiana. First, we provided a further direct validation of a rapid method of π tlp determination based on osmometer measurements of leaf osmotic potential at full hydration for five Amazonian tree species. Next, we analysed a dataset of 131 π tlp values for a range of species, seasons, size (including saplings), and leaf exposure. We found that early-successional species had less drought-tolerant leaves than late-successional species. Species identity was the major driver of π tlp variation, whereas season, canopy tree size and leaf exposure explained little variation. Shifts in π tlp from saplings to canopy trees varied across species, and sapling leaf drought tolerance was a moderate predictor of canopy tree leaf drought tolerance. Given its low within-species variability, we propose that π tlp is a robust trait, and is useful as one index of species' drought tolerance. We also suggest that measuring this trait would considerably advance our knowledge on leaf drought tolerance in hyperdiverse communities and would thus likely shed light on the resilience of such vulnerable species-rich ecosystem