Studies on an alkali-thermostable xylanase from Aspergillus fumigatus MA28

An alkalitolerant fungus, Aspergillus fumigatus strain MA28 produced significant amounts of cellulase-free xylanase when grown on a variety of agro-wastes. Wheat bran as the sole carbon source supported higher xylanase production (8,450 U/L) than xylan (7,500 U/L). Soybean meal was observed to be the best nitrogen source for xylanase production (9,000 U/L). Optimum medium pH for xylanase production was 8 (9,800 U/L), though, significant quantities of the enzyme was also produced at pH 7 (8,500 U/L), 9 (8,200 U/L) and 10 (4,600 U/L). The xylanase was purified by ammonium sulphate precipitation and carboxymethyl cellulose chromatography, and was found to have a molecular weight of 14.4 kDa with a Vmax of 980 μmol/min/mg of protein and a Km of approximately 4.9 mg/mL. The optimum temperature and pH for enzyme activity was 50 °C and pH 8, respectively. However, the enzyme also showed substantial residual activity at 60–70 °C (53–75%) and at alkaline pH 8–9 (56–88%)

The CEP5 Peptide Promotes Abiotic Stress Tolerance, As Revealed by Quantitative Proteomics, and Attenuates the AUX/IAA Equilibrium in Arabidopsis.

Peptides derived from non-functional precursors play important roles in various developmental processes, but also in (a)biotic stress signaling. Our (phospho)proteome-wide analyses of C-TERMINALLY ENCODED PEPTIDE 5 (CEP5)-mediated changes revealed an impact on abiotic stress-related processes. Drought has a dramatic impact on plant growth, development and reproduction, and the plant hormone auxin plays a role in drought responses. Our genetic, physiological, biochemical, and pharmacological results demonstrated that CEP5-mediated signaling is relevant for osmotic and drought stress tolerance in Arabidopsis, and that CEP5 specifically counteracts auxin effects. Specifically, we found that CEP5 signaling stabilizes AUX/IAA transcriptional repressors, suggesting the existence of a novel peptide-dependent control mechanism that tunes auxin signaling. These observations align with the recently described role of AUX/IAAs in stress tolerance and provide a novel role for CEP5 in osmotic and drought stress tolerance

DURAPI – Vers une meilleure connaissance et un accompagnement technique des exploitations apicoles professionnelles : durabilité, stratégies de renouvellement du cheptel et conséquences sur le fonctionnement global de l’exploitation

Variability of the production context, colony losses: professional beekeepers have to cope with several environmental and socio-economic issues to ensure the sustainability of their farm. Thus, the DURAPI project aimed at developing a sustainability assessment framework for bee farming operations through a participatory design involving the stakeholders from the beekeeping sector. We also considered the part of the colony and queen replacement strategy, which is central in the colony management: the existing replacement strategies were identified and their possible consequences on the farm sustainability, in particular on the work organisation, were studied. These results allowed us to develop training tools for future beekeepers. This project also provides several support tools for beekeeping advisors.Variabilité du contexte de production, pertes de colonies d’abeilles : les exploitations apicoles font aujourd'hui face à différentes problématiques environnementales comme socio-économiques. Dans ce contexte, le projet DURAPI a visé à élaborer un cadre d’évaluation de la durabilité de ces exploitations, à travers une démarche participative qui a impliqué de nombreux acteurs de la filière. Parallèlement, la place de la gestion du renouvellement des colonies et des reines dans cette durabilité a été considérée. Les principales stratégies de renouvellement du cheptel mises en place dans les exploitations ont ainsi été identifiées afin d’ensuite caractériser leurs conséquences possibles sur cette durabilité de l’exploitation, notamment en termes de temps et d’organisation du travail. Ces différents résultats ont donné lieu à la création de supports pour les formateurs en apiculture. Les méthodes développées dans le cadre du projet peuvent par ailleurs être mobilisées pour l’appui aux apiculteurs ou futurs installés