The evolution of photosynthesis in chromist algae through serial endosymbioses

Chromist algae include diverse photosynthetic organisms of great ecological and social importance. Despite vigorous research efforts, a clear understanding of how various chromists acquired photosynthetic organelles has been complicated by conflicting phylogenetic results, along with an undetermined number and pattern of endosymbioses, and the horizontal movement of genes that accompany them. We apply novel statistical approaches to assess impacts of endosymbiotic gene transfer on three principal chromist groups at the heart of long-standing controversies. Our results provide robust support for acquisitions of photosynthesis through serial endosymbioses, beginning with the adoption of a red alga by cryptophytes, then a cryptophyte by the ancestor of ochrophytes, and finally an ochrophyte by the ancestor of haptophytes. Resolution of how chromist algae are related through endosymbioses provides a framework for unravelling the further reticulate history of red algal-derived plastids, and for clarifying evolutionary processes that gave rise to eukaryotic photosynthetic diversity

Monilochaetes and allied genera of the Glomerellales, and a reconsideration of families in the Microascales

We examined the phylogenetic relationships of two species that mimic Chaetosphaeria in teleomorph and anamorph morphologies, Chaetosphaeria tulasneorum with a Cylindrotrichum anamorph and Australiasca queenslandica with a Dischloridium anamorph. Four data sets were analysed: a) the internal transcribed spacer region including ITS1, 5.8S rDNA and ITS2 (ITS), b) nc28S (ncLSU) rDNA, c) nc18S (ncSSU) rDNA, and d) a combined data set of ncLSU-ncSSU-RPB2 (ribosomal polymerase B2). The traditional placement of Ch. tulasneorum in the Microascales based on ncLSU sequences is unsupported and Australiasca does not belong to the Chaetosphaeriaceae. Both holomorph species are nested within the Glomerellales. A new genus, Reticulascus, is introduced for Ch. tulasneorum with associated Cylindrotrichum anamorph; another species of Reticulascus and its anamorph in Cylindrotrichum are described as new. The taxonomic structure of the Glomerellales is clarified and the name is validly published. As delimited here, it includes three families, the Glomerellaceae and the newly described Australiascaceae and Reticulascaceae. Based on ITS and ncLSU rDNA sequence analyses, we confirm the synonymy of the anamorph genera Dischloridium with Monilochaetes. Consequently Dischloridium laeënse, type species of the genus, and three related species are transferred to the older genus Monilochaetes. The teleomorph of D. laeënse is described in Australiasca as a new species. The Plectosphaerellaceae, to which the anamorph genus Stachylidium is added, is basal to the Glomerellales in the three-gene phylogeny. Stilbella annulata also belongs to this family and is newly combined in Acrostalagmus. Phylogenetic analyses based on ncLSU, ncSSU, and combined ncLSU-ncSSU-RPB2 sequences clarify family relationships within the Microascales. The family Ceratocystidaceae is validated as a strongly supported monophyletic group consisting of Ceratocystis, Cornuvesica, Thielaviopsis, and the type species of Ambrosiella. The new family Gondwanamycetaceae, a strongly supported sister clade to the Ceratocystidaceae, is introduced for the teleomorph genus Gondwanamyces and its Custingophora anamorphs. Four families are accepted in the Microascales, namely the Ceratocystidaceae, Gondwanamycetaceae, Halosphaeriaceae, and Microascaceae. Because of a suggested affinity of a Faurelina indica isolate to the Microascales, the phylogenetic position of the Chadefaudiellaceae is reevaluated. Based on the results from a separate ncLSU analysis of the Dothideomycetes, Faurelina is excluded from the Microascales and placed in the Pleosporales

Structural Color in Marine Algae

Structural colouration is widespread in the marine environment. Within the large variety of marine organisms, macroalgae represent a diverse group of more than 24,700 species. Some macroalgae have developed complex optical responses using different nanostructures and material compositions. In this review, we describe the mechanisms that are employed to produce structural colour in algae and provide a discussion on the functional relevance by analysing the geographical distribution and ecology in detail. In contrast to what is observed in the animal kingdom, we hypothesise that structural colour in algae predominantly functions for a non-communicative purpose, most likely protection from radiation damage, e.g. by harmful UV light. We suggest that the presence of structural colour in algae is likely influenced by local factors such as radiation intensity and turbidity of the water.Biotechnology and Biological Sciences Research Council (Grant ID: BBSRC David Phillips, 13 BB/K014617/1), European Research Council (Grant ID: ERC-2014-STG H2020 639088), Department of Chemistry, Cambridge (Philip and Patricia Brown Next Generation Fellowship), National Centre of Competence in Research “Bio-Inspired Materials”, Adolphe Merkle Foundatio

«... Enfants de l'aviron, toujours nous aimerons notre Bayonne» : Jean-Pierre Augustin et Alain Garrigou, Le rugby. Essai sur les Associations sportives, le Pouvoir et les Notables

Chadefaud Michel. «... Enfants de l'aviron, toujours nous aimerons notre Bayonne» : Jean-Pierre Augustin et Alain Garrigou, Le rugby. Essai sur les Associations sportives, le Pouvoir et les Notables. In: Revue géographique des Pyrénées et du Sud-Ouest, tome 57, fascicule 2, 1986. Pyrénées. pp. 276-277

Une formule originale de tourisme social : les gîtes ruraux

« Les gîtes ruraux individuels » et les « gîtes communaux » se répartissent au sud d'une ligne Bayonne-Besançon. L'étude des gîtes ruraux constitue une sorte de sondage des locations de vacances en milieu rural. D'une rentabilité non immédiate, le gîte rural donne aux agriculteurs une mentalité d'accueil car il facilite, plus que toute autre formule, la rencontre du rural et du citadin. Ce système permet la sauvegarde du pittoresque de nos campagnes. L'ensemble de la clientèle demeure « moyenne », bien que ce type d'hébergement s'adresse à un éventail social de plus en plus large car il facilite, par excellence, des vacances familiales. Le « gîte de week-end » se développe et se confond alors avec la résidence secondaire louée.Chadefaud Michel. Une formule originale de tourisme social : les gîtes ruraux. In: Revue géographique des Pyrénées et du Sud-Ouest, tome 39, fascicule 3, 1968. pp. 273-297

Autour de la bataille de Kadech : image et texte dans les choix de la « propagande » religieuse et politique de Ramsès II

Pendant le Nouvel Empire (1580-1085 av. J.-C) l’iconographie de Pharaon évolue à la faveur des conquêtes, tant en Nubie qu’en Asie. Sous le règne de Ramsès II le roi utilise tous les espaces sacrés pour mettre en scène ses actions tant par les inscriptions que par les images (bas-relief et statuaire). La bataille de Kadech (en Syrie, 1274 av. J.-C.) contre les Hittites fait l’objet d’un vaste programme de représentations dans plusieurs cités. Cinq temples d’Égypte figurent les variantes qui justifient l’exaltation de la vaillance du roi, médiateur des divinités et protecteur du pays. L’analyse de ces images montre d’une part l’enracinement de l’iconographie royale dans des traditions antérieures à Ramsès, liées dès l’Ancien Empire à la figuration des ennemis vaincus. D’autre part des innovations insistent sur l’action de Ramsès soutenu par Amon-Rê. La vaillance du roi et l’intervention divine sauvegardent les frontières de l’empire et assurent la paix à la population.Chadefaud Catherine. Autour de la bataille de Kadech : image et texte dans les choix de la « propagande » religieuse et politique de Ramsès II. In: Le pouvoir de l’image. Actes du 132e Congrès national des sociétés historiques et scientifiques, « Images et imagerie », Arles, 2007. Paris : Editions du CTHS, 2012. pp. 181-193. (Actes des congrès nationaux des sociétés historiques et scientifiques, 132-10