Presence of proline in salinized nutrient solution re-enforces the role of this amino acid in osmoregulation and protects lipid membrane peroxidation in Arabidopsis thaliana

Abstract Very little is known about the effect of proline addition on the accumulation of inorganic solutes (Na ) and soluble sugars in the model plant Arabidopsis thaliana. Therefore, the aim of the present study was to assess the effect of 10 mM proline (P) supply in the culture medium on water status and solute accumulation of Arabidopsis thaliana seedlings exposed to 50 mM NaCl (S). The decrease of leaf osmotic potential was more pronounced in P+S as compared to S plants, indicating that former plants were able to accumulate more compounds involved in the osmotic adjustment process. Leaf potassium concentration was reduced by 15, 21 and 25% in P, S and P+S plants respectively, as compared to the control. When compared to S or P treatments, leaf proline and soluble sugar were more accumulated under P+S treatment. Under saline conditions, exogenous proline increased leaf Na + , Ca 2+ and Mg 2+ concentrations by 27, 281 and 252%, respectively, as compared to the control. Interestingly, proline addition mitigated significantly the deleterious effects of salt on lipid membrane peroxidation. Regarding the contribution of soluble sugars to osmotic adjustment (OA), it amounted to 6% in S or P+S, plants. For proline, its contribution to OA did not exceed 3.4% under salinity (S), whereas in (P+S) treatment, it increased to 14.7%. As a whole, the positive effect of proline exogenous application under saline conditions could be partly explained by the enhanced role of this organic compound in osmoregulation and its likely protective effect against membrane lipid peroxidation

L'histoire du mouvement national tunisien : problématique générale et éléments de recherche

Jdey A. L'histoire du mouvement national tunisien : problématique générale et éléments de recherche. In: Horizons Maghrébins - Le droit à la mémoire, N°6, 1986. Relations Nord/Sud-Tunisie-CEE. pp. 104-113

Le Maghreb et le monde arabo-musulman dans les universités européennes : le cas de l'Université Française

Jdey Ahmed. Le Maghreb et le monde arabo-musulman dans les universités européennes : le cas de l'Université Française. In: Horizons Maghrébins - Le droit à la mémoire, N°5, 1985. Islam – Politique – Identité culturelle maghrébine. pp. 113-122

Photoprotective and anti-age capacities of some halophyte plants from the Breton coast and Tunisia

Dans ce travail, l’évaluation des activités antioxydantes, antibactérienne, anti-âge et photoprotectrices ont été effectuées sur les parties aériennes de douze halophytes : dont 6 Tunisiennes et 6 françaises montre une variabilité importante en fonction de l’espèce.Cependant, la fraction MeoH60% se distingue par son activité antioxydante, antibactérienne ainsi que pour l’activité écran pour les deux plantes sélectionnées. Ensuite, les fractions MeOH20%, et MeOH40% présentent une activité anti-élastase et anti-collagénase importante pour Haloxylon articulatum alors que pour daucus carota les fractions MeOH20% et MeOH100% présentent les activités anti-élastase et anti-collagénase les plus intéressantes.L’évaluation du potentiel cytotoxique des fractions sur la viabilité des kératinocytes humains indique une absence de toxicité puisqu’une viabilité de 100% des cellules est obtenue avec différentes concentrations (jusqu’à 100 μg/ml) et différents temps de contact (jusqu’à 24 h) des deux plantes. Toutes les activités biologiques montrées dans cette étude sont expliquées par l'existence de divers composés phénoliques essentiellement: la scopolétine (coumarine aglycone), l’épigallocatéchine, l’esculétine et l’isorhamnétine triglycoside, l’acide caféique, l’acide chlorogénique, la lutéoline et sa forme glycosylé( la lutéoline-3-O-glucoside), enfin l’apigénine libre et sa forme glycosylée.In this work, the evaluation of antioxidant, anti-bacterial, anti-aging and photoprotective activities was carried out on the aerial parts of twelve halophytes: 6 Tunisian and 6 French shows a high variability according to the species. A screening based on these activities allowed the selection of the two most promising species (Haloxylon articulatum and Daucus carota). A fractionation by adsorption chromatography of their hydroalcoholic extracts was used to specify its antioxidant, antimicrobial, anti-aging and cytotoxic capacities. The results show a high variability between the fractions. The MeOH20% and MeOH100% fractions showed the most interesting anti-elastase and anti-collagenase activities. The evaluation of the cytotoxic potential of the fractions on the viability of human keratinocytes indicates an absence of toxicity since a viability of 100% of the cells is obtained with different concentrations (up to 100 μg / ml) and different contact times (At 24 h) of the two plants.These biological activities were correlated to the presence of various phenolic compounds mainly: scopoletin (coumarin aglycone), epigallocatechin, esculetin , isorhametin triglycoside, caffeic acid, chlorogenic acid, Luteolin and its glycosylate form (luteolin-3-O-glucoside), and finally free apigenin and its glycosylate form

Antioxidant and selective anticancer activities of two Euphorbia species in human acute myeloid leukemia

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