Les ambassadeurs suisses à Paris en 1663. Usages protocolaires : entre tradition et politique

Louis XIV invite les ambassadeurs des cantons suisses à jurer le renouvellement d’alliance le 18 novembre 1663 à Paris. L’étude du protocole en vigueur lors de cette cérémonie permettra une meilleure compréhension du rôle des ambassadeurs du Corps helvétique dans une mise en scène savamment orchestrée

High gellan gum concentration and secondary somatic embryogenesis: two key factors to improve somatic embryo development in Pseudotsuga menziesii [Mirb.]

Douglas-fir is a conifer species of major economic importance worldwide, including Western Europe and New Zealand. Herein we describe some characterization and significant refinement of somatic embryogenesis in Douglas-fir, with focus on maturation. The most typical structures observed in the embryonal masses were large polyembryogenic centres (up to 800-1500 μm) with a broad meristem, creating a compact ce ll “package” with suspensor cells. Singulated somatic embryos composed of both a embryonal head (300-400 μm) and long, tightly arranged suspensor were also frequent. Embryo development was enhanced following embryonal mass dispersion on filter paper discs at low density (50-100 mg fresh mass). Moreover, increasing gellan gum concentration in maturation medium (up to 10 g L-1) improved both the quantity and quality of cotyledonary somatic embryos (SEs), which were subsequently able to germinate and develop into plantlets at high frequency. Embryogenic yield was highly variable among the seven embryogenic lines tested (27-1544 SE g-1 fresh mass). Interestingly secondary somatic embryogenesis could be induced from cotyledonary SEs of both low- and highly-productive lines with some useful practical outcomes: secondary lines from low-performance lines (30-39 478 SE g-1) displayed significantly higher embryogenic yield (148-1343 SE g-1). In our best conditions, the total protein content in cotyledonary SEs increased significantly with maturation 41 duration (up to 150 μg mg-1 fresh mass after 7 weeks) but remained below that of mature zygotic embryos (300 μg mg-1). The protein pattern was similar in both somatic and zygotic embryos, with major storage proteins identified as 7S-vicilin- and legumin-like proteins

Le diplomate en question (XVe-XVIIIe siècles)

Ambassadeurs, envoyés, négociateurs, messagers, chevaucheurs… autant de vocables rencontrés pour désigner les acteurs de la diplomatie du Moyen Age aux Temps modernes. Si l’histoire des relations extérieures connaît un regain d’intérêt depuis une décennie, l’attention des chercheurs se porte encore trop souvent sur l’art de la négociation et les grands traités. On s’est, de fait, encore peu intéressé aux hommes sur qui reposaient les ambassades. Dans le but de saisir les évolutions et les pratiques de ce personnel diplomatique, le présent volume embrasse la longue durée, du XVe au XVIIIe siècle, et retient l’espace helvétique, au sens large, comme cadre spatial. La Suisse, par son importance politique, militaire et économique vis-à-vis de ses voisins, offre un espace propice au questionnement. Ce volume collectif apporte des éléments novateurs pour mettre en lumière les modalités de recrutement et les compétences des acteurs de la négociation étrangère auprès des cantons, qu’il s’agisse des ambassadeurs ou des membres du personnel secondaire. Fort de douze contributions réunissant des chercheurs de huit universités suisses et étrangères, cet ouvrage présente les résultats du colloque international qui s’est tenu à l’Université de Lausanne les 11 et 12 décembre 2009 sur «Le diplomate en question»

Repetitive somatic embryogenesis induced cytological and proteomic changes in embryogenic lines of Pseudotsuga menziesii

International audienc

Did cotyledonary somatic embryos of Pinus pinaster Ait. similar to cotyledonary zygotic embryos ?

International audienc

Did cotyledonary somatic embryos of Pinus pinaster Ait. similar to cotyledonary zygotic embryos ?

International audienc

Are cotyledonary somatic embryos of Pinus pinaster Ait. equivalent to the zygotic counterpart ?

In maritime pine, improved protocols are now available for the whole somatic embryogenesis process i.e. from initiation of embryogenic tissue to somatic plant regeneration. However, field trials established in France from somatic plant material have consistently revealed that somatic embryos (SEs) developed at a lower initial growth rate compared to control seedlings. A better understanding of SEs maturation is therefore required in order to produce high-quality, vigorous somatic plants. SEs are currently matured for 12 weeks to reach the cotyledonary stage before being germinated and converted to plantlets. Although regeneration success is highly dependent on SEs quality, the harvesting date is still determined from morphological features. This empirical method does not provide any accurate information about embryo quality with respect to storage compounds (proteins, carbohydrates). We first analyzed SEs matured for 10, 12 and 14 weeks by carrying out biological (dry weight, water content) and biochemical measurements (total protein and carbohydrate contents). No significant difference could be found between collection dates, suggesting that SE harvesting after 12 weeks maturation is appropriate. Cotyledonary SEs were then compared to various stages, from fresh to fully desiccated, in the development of cotyledonary zygotic embryos (ZEs). Using hierarchical ascendant cluster analysis, we demonstrated that cotyledonary SEs matured for 12 weeks are most similar to fresh cotyledonary ZEs sampled from late July to early August (as indicated by dry weight, water content, sucrose, RFOs content, RFO/Sucrose ratio) or at any time up to October (with respect to total protein). Both types of embryo exhibited similar carbohydrate and protein content and signatures. This high level of similarity (94.5%) was further supported by proteome profiling. Highly expressed proteins included storage, stress-related, late embryogenesis abundant (LEA) and energy metabolism proteins. By comparing overexpressed proteins in developing and cotyledonary SEs or ZEs, some (23 proteins) could be identified as candidate biomarkers for the late, cotyledonary stage. Of these, 18 belonged to five large families of proteins including five HSPs, four LEAs and two other stress-related proteins (aldose reductase, 6-phosphogluconate dehydrogenase), five storage proteins and two proteins involved in purine metabolism (adenosine kinase 2, SAM synthase). This is the first report of useful generic protein markers for monitoring embryo development in maritime pine. Our results also suggest that improvements of SEs quality may be achieved if the current maturation conditions are refined

Cotyledonary somatic embryos of Pinus pinaster Ait. most closely resemble fresh, maturing cotyledonary zygotic embryos: biological, carbohydrate and proteomic analyses.

International audienceCotyledonary somatic embryos (SEs) of maritime pine are routinely matured for 12 weeks before being germinated and converted to plantlets. Although regeneration success is highly dependent on SEs quality, the date of harvesting is currently determined mainly on the basis of morphological features. This empirical method does not provide any accurate information about embryo quality with respect to storage compounds (proteins, carbohydrates). We first analyzed SEs matured for 10, 12 and 14 weeks by carrying out biological (dry weight, water content) and biochemical measurements (total protein and carbohydrate contents). No difference could be found between collection dates, suggesting that harvesting SEs after 12 weeks is appropriate. Cotyledonary SEs were then compared to various stages, from fresh to fully desiccated, in the development of cotyledonary zygotic embryos (ZEs). We identified profiles that were similar using hierarchical ascendant cluster analysis (HCA). Fresh and dehydrated ZEs could be distinguished, and SEs clustered with fresh ZEs. Both types of embryo exhibited similar carbohydrate and protein contents and signatures. This high level of similarity (94.5 %) was further supported by proteome profiling. Highly expressed proteins included storage, stress-related, late embryogenesis abundant and energy metabolism proteins. By comparing overexpressed proteins in developing and cotyledonary SEs or ZEs, some (23 proteins) could be identified as candidate biomarkers for the late, cotyledonary stage. This is the first report of useful generic protein markers for monitoring embryo development in maritime pine. Our results also suggest that improvements of SEs quality may be achieved if the current maturation conditions are refined

Cytological, biochemical and molecular events of the embryogenic state in Douglas-fir (Pseudotsuga menziesii [Mirb.])

Somatic embryogenesis techniques have been developed for most coniferous species, but only using very juvenile material. To extend the techniques' scope, better integrated understanding of the key biological, physiological and molecular characteristics of embryogenic state is required. Therefore, embryonal masses (EMs) and non-embryogenic calli (NECs) have been compared during proliferation at multiple levels. EMs and NECs originating from a single somatic embryo (isogenic lines) of each of three unrelated genotypes were used in the analyses, which included comparison of the lines' anatomy by transmission light microscopy, transcriptomes by RNAseq Illumina sequencing, proteomes by free-gel analysis, contents of endogenous phytohormones (indole-3-acetic acid, cytokinins and ABA) by LC-MS analysis, and soluble sugar contents by HPLC. EMs were characterized by upregulation (relative to levels in NECs) of transcripts, proteins, transcription factors and active cytokinins associated with cell differentiation accompanied by histological, carbohydrate content and genetic markers of cell division. In contrast, NECs were characterized by upregulation (relative to levels in EMs) of transcripts, proteins and products associated with responses to stimuli (ABA, degradation forms of cytokinins, phenols), oxidative stress (reactive oxygen species) and carbohydrate storage (starch). Sub-Network Enrichment Analyses that highlighted functions and interactions of transcripts and proteins that significantly differed between EMs and NECs corroborated these findings. The study shows the utility of a novel approach involving integrated multi-scale transcriptomic, proteomic, biochemical, histological and anatomical analyses to obtain insights into molecular events associated with embryogenesis and more specifically to the embryogenic state of cell in Douglas-fir