Different response between woody core and bark of goat willow biomass to concentrated phosphoric acid pretreatment prior to enzymatic saccharification was investigated as changes of chemical ...compositions, carbohydrate compositions, and crystallinity of cellulose before and after pretreatment. Goat willow has different chemical composition between bark and woody core, higher polysaccharides content in woody core as 74.6% compared with 61.0% in bark. In bark, hydrophobic and hydrophilic extractives contents was 20.4% compared with 8.1% in woody core.
Parts of extractives and carbohydrates were removed by concentrated phosphoric acid pretreatment, and this trend was more obvious in bark than woody core. In bark, 60% of xylan and 30% of cellulose was removed by acid pretreatment but only 40% of xylan and 8.3% of cellulose in woody core. Removal of polysaccharides in cell wall and destruction of crystal structure (cellulose crystallinity reduction) in cellulose caused the more enzymatic saccharification by commercial cellulases cocktails. Bark showed three times higher cellulose to glucose conversion by cellulases but woody core was two times higher than those of untreated.
•Phosphoric acid pretreatment decreased the crystallinity of cellulose and removed xylan.•More xylan removal and decrystallization of cellulose occurred in bark than woody part.•Bark was more hydrolyzed than woody part by commercial cellulases.•Bark in Goat willow was good raw material for bio-alcohol production.
Salix caprea L. is an ornamental plant with prominent antioxidant activity. In the last decades Salix caprea bud extracts (SCBEs) have been used for the treatment of oxidative stress related ...disorders.
A large part of cellular functions depends on the amount of intracellular Ca2+ concentration which in turn is mainly determined by Ca2+ ions movements across plasma membrane as well as by Ca2+ released from the stores. For better evaluating the mechanism of action of SCBEs, we focused on the effect of SCBEs on voltage gated Ca2+ channels (VGCCs) functioning and related catecholamines secretion in mouse chromaffin cells (MCCs). These latter are neuroendocrine cells that share a wide variety of functions with neurons. They are particularly interesting for studying the relationship between VGCCs activation and catecholamines secretion both in control and under stressful conditions.
We focused on the effect of SCBEs on VGCCs being these latter considered one of the main pathway of Ca2+ influx across plasma membrane. Ca2+ currents and capacitance changes were measured in patch clamp experiments performed in voltage clamp configuration.
We show that SCBEs inhibited VGCCs in a dose dependent manner. On average, the saturating concentration of SCBEs (SCBEsmax) is able to block 36% of the maximum Ca2+ current amplitude (ICa) without selectivity for L (ICa, L) or non-L type (ICa, non-L) Ca2+ channels. Furthermore, ICa inhibition is not followed by alteration of VGCCs gating kinetics, but is responsible for a marked decrease of Ca2+ dependent catecholamines secretion.
We conclude that the ability of SCBEs to inhibit VGCCs function, known to be potentiated during oxidative stress, could contribute to the already known antioxidant properties of Salix caprea L. We finally suggest that the inhibitory effect of SCBEs on catecholamines secretion may contribute to treat stress dependent cellular dysfunctions.
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Baranowskiella ehnstromi est citée des massifs du Vercors (Isère), de la Chartreuse (Savoie) et du Jura (Ain). De nombreux exemplaires de cette espèce hyper-spécialisée ont été récoltés directement ...sur son champignon hôte : Phellinopsis conchata (Pers.) Dai, 2010. Ces stations prolongent vers le sud et en altitude l’aire de distribution de B. ehnstromi.
Baranowskiella ehnstromi Sorensson : impressive actuality for a miniaturised saproxylic installed in the French Alps (Coleoptera, Ptiliidae).
Baranowskiella ehnstromi is cited from the mountains of Vercors (Isère), Chartreuse (Savoy) and Jura (Ain). Numerous individuals of this hyper-specialized species have been recorded directly on their host fungus : Phellinopsis conchata. These new localities extend the distribution area of B. ehnstromi southward and in altitude.
Les populations de Cervidés sont en rapide augmentation en Europe de l'ouest, où elles causent des dégâts à la forêt. Ceci nécessite de mieux comprendre les déterminants de leurs choix alimentaires. ...Nous avons étudié comment la disponibilité relative de deux espèces d'arbres influence les choix alimentaires du cerf Cervus elaphus en testant trois hypothèses : (i) une sélectivité accrue pour les espèces rares souvent évoquée par les forestiers, (ii) une sélectivité accrue pour l'espèce préférée lorsque son abondance augmente, prédite par les modèles d'optimisation, et (iii) une sélectivité indépendante de la disponibilité relative des espèces végétales comme cela a déjà été montré chez l'élan et le chevreuil. Nous avons pour cela observé les choix alimentaires de six biches dans des tests de courte durée, lorsqu'on faisait varier l'abondance relative du saule Salix caprea par rapport au frêne Fraxinus excelsior. La relation entre la consommation des deux espèces et leur disponibilité relative indique une préférence du cerf pour le frêne par rapport au saule, et à court terme, une sélectivité indépendante de la disponibilité relative des deux espèces. L'intensité de la préférence pour le frêne variait selon les animaux, mais ceux-ci ont réagi de manière identique aux variations d'abondance des deux espèces. Nos résultats éclairent les choix alimentaires du cerf à l'échelle du site alimentaire, mais d'autres travaux seront nécessaires pour appliquer ces résultats de manière à limiter les dégâts forestiers
