Effects of osmotic stress on Chenopodium quinoa seed germination.

Quinoa is a pseudo-cereal native to the Andes known for its exceptional adaptation to extreme soil and climate conditions. The study of the response of Chenopodium quinoa to osmotic stress and the contribution to improving its yield aims to ensure production in arid and semi-arid regions as an alternative crop. The aim of this study is to test the germination capacity of 5 selected varieties; CQ-57, UDEC-2; ICBA-4, ICBA-5 and 115-R subjected to varying osmotic pressures using solutions of PEG-6000 and NaCl. Seeds are incubated at 25 °C for 10 days. Results showed that osmotic stress increases the lag phase but does not affect the germination rate at low concentrations of PEG and NaCl. While for high concentrations the germination rates decrease as compared to controls. Radicale and hypocotyl lengths decreased with increasing the degree of osmotic stress. The effects of osmotic stress are comparable in the 5 varieties. At high concentration of PEG or NaCl, ICBA-5 and CQ-57 exhibited the highest value of germination rate showing the capacity of these varieties to establish itself in regions suffering from salinity or water deficit

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

In republic : a material history of the Franco-Prussian war and the communes in the major cities of southern France (Lyon, Marseille, Toulouse, Bordeaux), 1870-1871

Les villes sont particulièrement affectées par les processus de transition politique. Alors que Lyon, Marseille et Bordeaux ont connu, sous le Second Empire, des travaux comparables à ceux d'Haussmann à Paris, la proclamation de la République, le 4 septembre 1870, et les communes qui s'y installent, plus ou moins durablement, avant même la Commune de Paris, interrogent les logiques urbaines du changement de régime. Noms de rues modifiés, iconoclasme massif, lieux réappropriés, nouveaux usages de l'espace public se doublent de pratiques spécifiques qui bouleversent l'ordre urbain. La recréation de la garde nationale et l'arrivée massive de volontaires étrangers, dans le contexte de la guerre franco-prussienne, modifient ainsi la physionomie des villes du Sud. En outre, alors que la capitale est soumise à un siège, les municipalités du Sud bénéficient d'une inédite autonomie, à l'origine de créations institutionnelles originales. Ces villes apparaissent ainsi comme des laboratoires républicains qu'il s'agit, dans ce travail, d'étudier sous l'angle du matériel et du genre. Des catégories souvent invisibles dans les analyses des communes émergent ainsi. Elles permettent de saisir finement les mécanismes révolutionnaires comme les freins aux bouleversements politiques, et de comprendre les décalages chronologiques entre Paris et la province. Ce sont ainsi les débuts de la Troisième République qui se trouvent envisagés à nouveaux frais.Cities are particularly affected by political transitions. Under the Second Empire, Lyon, Marseille and Bordeaux underwent works comparable to those carried out by Haussmann in Paris, but the proclamation of the Republic on September 4, 1870, and the communes that settled there, more or less permanently, even before the Paris Commune, questioned the urban logics of the change of regime. Altered street names, massive iconoclasm, reappropriated places and new uses for public space are coupled with specific practices that upset the urban order. The recreation of the National Guard and the massive influx of foreign volunteers, against the backdrop of the Franco-Prussian war, changed the face of the towns in the South. What's more, while the capital was under siege, the municipalities of the South enjoyed an unprecedented degree of autonomy, which gave rise to a number of original institutional creations. These cities thus appear as republican laboratories, which this work will study from the angle of material and gender. In this way, categories often invisible in analyses of communes emerge. They allow us to grasp revolutionary mechanisms as well as the obstacles to political upheaval, and to understand the chronological gaps between Paris and the provinces. The beginnings of the Third Republic are thus seen in a new light

Etude des propriétés énantiosélectives de la vancomycine (application à la séparation par chromatographie liquide haute performance des énantiomères d'acides aminés dansylés)

La séparation des énantiomères est d'un grand intérêt pour les industries pharmaceutiques, chimiques et agrochimiques. Parmi les diverses techniques de résolution chirale la chromatographie liquide haute performance (CLHP) avec l'utilisation d'une phase stationnaire chirale constitue à l'heure actuelle la méthodologie de choix. Parmi les sélecteurs chiraux utilisés en CLHP, la vancomycine permet de séparer un grand nombre d'énantiomères de molécules d'intérêt biologique ou thérapeutique. Néanmoins, les mécanismes de rétention et de séparation chirale impliqués ne sont pas totalement élucidés. Ce travail a donc pour but d'étudier les mécanismes d'interactions mis enjeu dans la fixation et la séparation énantiosélective des acides aminés dansylés, et d'examiner par la suite l'effet de la dimérisation et de l'hétérodimérisation de la vancomycine sur ses propriétés énantiosélectives. Des modèles d'interactions entre la vancomycine et les solutés ont été développés afin de valider les résultats expérimentaux. Ainsi, nous avons montré que les acides aminés dansylés interagissent considérablement avec la poche aglycone de la vancomycine, l'effet hydrophobe étant fortement impliqué. Par ailleurs, la discrimination chirale des acides aminés dansylés semble être gouvernée essentiellement par des interactions polaires et des répulsions stériques. Nous avons aussi montré que la dimérisation de la vancomycine améliore nettement les propriétés énantiosélectives de ce glycopeptide pour la reconnaissance des acides aminés dansylés.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Effects of osmotic stress on Chenopodium quinoa seed germination.

Quinoa is a pseudo-cereal native to the Andes known for its exceptional adaptation to extreme soil and climate conditions. The study of the response of Chenopodium quinoa to osmotic stress and the contribution to improving its yield aims to ensure production in arid and semi-arid regions as an alternative crop. The aim of this study is to test the germination capacity of 5 selected varieties; CQ-57, UDEC-2; ICBA-4, ICBA-5 and 115-R subjected to varying osmotic pressures using solutions of PEG-6000 and NaCl. Seeds are incubated at 25 °C for 10 days. Results showed that osmotic stress increases the lag phase but does not affect the germination rate at low concentrations of PEG and NaCl. While for high concentrations the germination rates decrease as compared to controls. Radicale and hypocotyl lengths decreased with increasing the degree of osmotic stress. The effects of osmotic stress are comparable in the 5 varieties. At high concentration of PEG or NaCl, ICBA-5 and CQ-57 exhibited the highest value of germination rate showing the capacity of these varieties to establish itself in regions suffering from salinity or water deficit