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| Ramond, Pierre; Sourisseau, Marc; Simon, Nathalie; Romac, Sarah; Schmitt, Sophie; Rigaut-jalabert, Fabienne; Henry, Nicolas; De Vargas, Colomban; Siano, Raffaele. |
| The study of protistan functional diversity is crucial to understand the dynamics of oceanic ecological processes. We combined the metabarcoding data of various coastal ecosystems and a newly developed trait‐based approach to study the link between taxonomic and functional diversity across marine protistan communities of different size‐classes. Environmental DNA was extracted and the V4 18S rDNA genomic region was amplified and sequenced. In parallel, we tried to annotate the Operational Taxonomic Units (OTUs) from our metabarcoding dataset to 30 biological traits using published and accessible information on protists. We then developed a method to study trait correlations across protists (i.e. trade‐offs) in order to build the best functional groups.... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00478/58964/61554.pdf |
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| Chapelle, Annie; Le Bec, Claude; Amzil, Zouher; Dreanno, Catherine; Guillou, Laure; Klouch, Khadidja; Labry, Claire; Le Gac, Mickael; Pineau-guillou, Lucia; Siano, Raffaele; Abernot, Chantal; Andrieux, Francoise; Caradec, Florian; Destombe, Christophe; Dia, A.; Doner, Anne; Duval, Julia; Gouriou, Jeremie; Lazure, Pascal; Le Brun, Luc; Le Gal, Dominique; Malestroit, Pascale; Petton, Sebastien; Plus, Martin; Quere, Julien; Savar, Veronique; Schmitt, Sophie; Terre, A.; Youenou, Agnes. |
| Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été élaboré avec la Région Bretagne dans le cadre du développement du port de Brest. L’Ifremer a organisé un échantillonnage dans l’estuaire de la rivière de Daoulas, zone la plus touchée en 2012, au cours des printemps-été 2013 et 2014. Un suivi de la présence d’A. minutum dans les sédiments a également été réalisé en hiver 2014. De ces suivis, des mesures réalisées au laboratoire à ce jour, des simulations du modèle Prévimer ainsi que des résultats du réseau Rephy et Velyger, il ressort que: * La rade de Brest peut aujourd’hui être considérée comme une zone à risque pour Alexandrium minutum. En effet, depuis 2012... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00254/36487/35029.pdf |
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| Lelchat, Florian; Cozien, Joelle; Le Costaouec, Tinaig; Brandily, Christophe; Schmitt, Sophie; Baudoux, Anne-claire; Colliec-jouault, Sylvia; Boisset, Claire. |
| Alteromonas macleodii subsp. fijiensis biovar deepsane is a deep-sea ecotype exopolysaccharide-producing bacteria isolated from the polychaete annelid Alvinella pompejana. The high molecular weight biopolymer HYD657 produced by this strain, is the first marine exopolysaccharide (EPS) to be commercialized for cosmetic use. Depolymerization methods are necessary to elucidate the complete structure of this EPS and to generate potentially bioactive oligosaccharides. Enzymatic methods are useful for elucidating polysaccharide structure because they specifically cleave glycosidic bonds and do not require harsh chemical conditions. The HYD657 EPS is structurally complex and no commercially available enzymes are able to effectively degrade it. Here, we present the... |
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Palavras-chave: Marine Alteromonas macleodii sp strain; Bacterial exopolysaccharides; Microbial extracellular enzymes; Endogenous enzymatic degradation. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00240/35129/33893.pdf |
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| Chalkiadakis, Eletherios; Dufourcq, R.; Schmitt, Sophie; Brandily, Christophe; Kervarec, N.; Coatanea, Denis; Amir, H.; Loubersac, Lionel; Chanteau, S.; Guezennec, Jean; Dupont-rouzeyrol, M.; Simon-colin, Christelle. |
| Aims Exopolysaccharides (EPS) are industrially valuable molecules with numerous useful properties. This study describes the techniques used for the identification of a novel Vibrio bacterium and preliminary characterization of its EPS. Methods and Results Bioprospection in marine intertidal areas of New Caledonia followed by screening for EPS producing brought to selection of the isolate NC470. Phylogenetic analysis (biochemical tests, gene sequencing and DNADNA relatedness) permitted to identify NC470 as a new member of the Vibrio genus. The EPS was produced in batch fermentation, purified using the ultrafiltration process and analysed by colorimetry, Fourier Transform Infrared spectroscopy, gas chromatography, Nuclear Magnetic Resonance and HPLC-size... |
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Palavras-chave: Biopolymers; Biotechnology; Exopolysaccharide; Fermentation biotechnology. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00144/25501/24036.pdf |
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| Ramond, Pierre; Siano, Raffaele; Schmitt, Sophie; De Vargas, Colomban; Marié, Louis; Memery, Laurent; Sourisseau, Marc. |
| Oceanic physics at fine scale; e.g. eddies, fronts, filaments; are notoriously difficult to sample. However, an increasing number of theoretical approaches hypothesize that these processes affect phytoplankton diversity which have cascading effects on regional ecosystems. In 2015, we targeted the Iroise Sea (France) and evidenced the setting up of the Ushant tidal front from the beginning of spring to late summer. Seawater samples were taken during three sampling cruises and DNA-barcoding allowed us to investigate patterns of eukaryotic phytoplankton diversity across this front. First focusing on patterns of taxonomic richness, we evidenced that the front harbored a hotspot of eukaryotic phytoplankton diversity sustained throughout summer. We then detail... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78933/81307.pdf |
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| Dorin-semblat, Dominique; Schmitt, Sophie; Semblat, Jean-philippe; Sicard, Audrey; Reininger, Luc; Goldring, Dean; Patterson, Shelley; Quashie, Neils; Chakrabarti, Debopam; Meijer, Laurent; Doerig, Christian. |
| The Plasmodium falciparum kinome includes a family of four protein kinases (Pfnek-1 to -4) related to the NIMA (never-in-mitosis) family, members of which play important roles in mitosis and meiosis in eukaryotic cells. Only one of these, Pfnek-1, which we previously characterized at the biochemical level, is expressed in asexual parasites. The other three (Pfnek-2, -3 and -4) are expressed predominantly in gametocytes, and a role for nek-2 and nek-4 in meiosis has been documented. Here we show by reverse genetics that Pfnek-1 is required for completion of the asexual cycle in red blood cells and that its expression in gametocytes in detectable by immunofluorescence in male (but not in female) gametocytes, in contrast with Pfnek-2 and Pfnek-4. This... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00175/28578/26965.pdf |
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| Gras, S; Chaumont, V; Fernandez, B; Carpentier, P; Charrier Savournin, F; Schmitt, Sophie; Pineau, C; Flament, Didier; Hecker, A; Forterre, P; Armengaud, J; Housset, D. |
| The human XAB1/ MBDin GTPase and its close homologues form one of the ten phylogenetically distinct families of the SIMIBI ( after signal recognition particle, MinD and BioD) class of phosphate- binding loop NTPases. The genomic context and the partners identified for the archaeal and eukaryotic homologues indicate that they are involved in genome maintenance - DNA repair or replication. The crystal structure of PAB0955 from Pyrococcus abyssi shows that, unlike other SIMIBI class G proteins, these highly conserved GTPases are homodimeric, regardless of the presence of nucleotides. The nucleotide- binding site of PAB0955 is rather rigid and its conformation is closest to that of the activated SRP G domain. One insertion to the G domain bears a strictly... |
| Tipo: Text |
Palavras-chave: Structure; SIMIBI; Replication; GTPase; Crystal. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-4724.pdf |
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