Novel molecular markers for late phases of the growth cycle of Arabidopsis thaliana cell-suspension cultures are expressed during organ senescence

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Combined Rheological and Ultrasonic Study of Alginate and Pectin Gels near the Sol-Gel Transition

International audienceThe sol-gel transition of biopolymer mixtures has been investigated by rheological and ultrasonic measurements. A scaling analysis of the data was performed for both types of measurements. A gel time was determined from rheology for the pure pectin samples, and the data could be fitted to a universal scaling form near the transition point. Its critical exponents are in good agreement with the predictions of scalar percolation theory. In addition, the ultrasonic signal of the pectin samples close to the transition was analyzed in terms of a high-frequency scaling approach for the attenuation and the velocity. For the alginate samples and the mixtures, for which the gel point cannot be determined reliably from rheology, the ultrasonic measurements were analyzed using the same scaling form as for the pectin sample, thus providing a method for estimating the gel point, even in the absence of rheological data

Physico-chemical properties of carrageenan gels in presence of various cations.

Phase separation and gelation induced by addition of monovalent and divalent cations in iota and kappa carrageenan solutions were investigated as a function of the polymer and cation concentrations. Rheological measurements have also been carried out at a given polymer concentration. The storage modulus (G') determined at a cation/polymer ratio was always higher for kappa- than for iota-carrageenan. For iota carrageenan, G' increased slowly with the monovalent salt concentration and more quickly with the divalent salt concentration. At the opposite, for kappa carrageenan, G' increased more rapidly in the presence of KCl than with calcium or copper. Nevertheless for large salt concentrations, G' became independent of the type and concentration of cations in the kappa carrageenan solution

Plant gene register: Mtlec3 (GenBank X82216), a new member of the Medicago truncatula lectin gene family

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Nouvelles questions de recherche en bioéconomie

Le défi de la bioéconomie est de concilier 3 approches différentes : les demandes et les comportements des citoyens-consommateurs, la préservation des écosystèmes et de leurs capacités de production de biens consommables et de services écosystémiques, et le croisement de la rationalité des flux verticaux (filière) de biomasses, d’énergie et d’informations à celle des usages des sols (systèmes de cultures et forestiers, villes, régions…). Suite au colloque européen sur la bioéconomie les 28 et 29 juin 2017 à Paris, rassemblant 320 personnes venant de pays européens, d’Amérique du Nord et du Sud, et d’Afrique, 5 besoins clés ont été identifiés : (a) le passage des filières au système, (b) le renforcement des leviers technologiques, organisationnels et réglementaires pour les transitions, (c) le besoin de représentations et de modélisations dans une vision à 2050, (d) des politiques publiques dédiées et (e) l’évaluation de la durabilité. 11 recommandations ont été émises pour promouvoir le développement de la bioéconomie

An inventory of 1152 expressed sequence tags obtained by partial sequencing of cDNAs from Arabidopsis thaliana

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