%0 Journal Article %J Comptes Rendus. Biologies %D 2022 %T Light-driven processes: key players of the functional biodiversity in microalgae %A Falciatore, Angela %A Bailleul, Benjamin %A Boulouis, Alix %A Bouly, Jean-Pierre %A Bujaldon, Sandrine %A Cheminant-Navarro, Soizic %A Choquet, Yves %A Vitry, Catherine de %A Eberhard, Stephan %A Jaubert, Marianne %A Kuras, Richard %A Lafontaine, Ingrid %A Landier, Sophie %A Selles, Julien %A Vallon, Olivier %A Wostrikoff, Katia %B Comptes Rendus. Biologies %V 345 %P 1–24 %G eng %U https://comptes-rendus.academie-sciences.fr/biologies/articles/10.5802/crbiol.80/ %R 10.5802/crbiol.80 %0 Journal Article %J Journal of the Marine Biological Association of the United Kingdom %D 2022 %T Limpet larvae (Patella aspera Röding, 1798), obtained by gonad dissection and fecundation in vitro, settled and metamorphosed on crustose coralline algae %A Castejón, Diego %A Nogueira, Natacha %A Andrade, Carlos A. P. %K Early postlarvae %K lecithotrophy %K metamorphosis %K oocyte alkalinization %K pediveliger larvae %K RCC3458 %K settlement %X

The limpet Patella aspera Röding, 1798, is a native species from the Macaronesian region whose fishing is regulated. The early life of limpets, including the settlement process, is poorly known thus far. The current study evaluated different substrates to induce settlement in P. aspera, including microalgae strains (Halamphora coffeaeformis, Navicula incerta and Pavlova sp.) and crustose coralline algae (CCA) obtained from limpet shells. The results showed that gametes obtained by dissection and matured artificially using alkalinized seawater baths can produce viable larvae able to metamorphose to juveniles. Feeding was not required during larval development, suggesting lecithotrophy. Early postlarvae were identified by the shedding of the velum, and juveniles were identified by teleoconch and active grazing behaviour. The presence of CCA shortened the timing for settlement and increased the ratio of juveniles. The type and abundance of CCA can influence settlement success. Moreover, the results suggested that settlement and metamorphosis in true limpets (Patellogastropoda) might be triggered by a two-step mechanism, i.e. a first cue influencing the shift between swimming and crawling activity and a second cue determining settlement and metamorphosis to early postlarvae and juveniles.

%B Journal of the Marine Biological Association of the United Kingdom %P 1–12 %8 feb %G eng %R 10.1017/S0025315421000916 %0 Journal Article %D 2021 %T Les Efflorescences de Lepidodinium chlorophorum au large de la Loire et de la Vilaine : Déterminisme et conséquences sur la qualité des masses d’eau côtières %A Schapira, Mathilde %A Roux, Pauline %A Andre, Coralie %A Mertens, Kenneth %A Bilien, Gwenael %A Terre Terrillon, Aouregan %A Le Gac-Abernot, Chantal %A Siano, Raffaele %A Quéré, Julien %A Bizzozero, Lucie %A Bonneau, Francoise %A Bouget, Jean-Francois %A Cochennec-Laureau, Nathalie %A Collin, Karine %A Fortune, Mireille %A Gabellec, Raoul %A Le Merrer, Yoann %A Manach, Soazig %A Pierre-Duplessix, Olivier %A Retho, Michael %A Schmitt, Anne %A Souchu, Philippe %A Stachowski-Haberkorn, Sabine %K ? No DOI found %K rcc %K RCC1489 %X Ce projet, organisé en trois actions, avait pour objectif de mieux évaluer les risques d’eaux colorées vertes se produisant sur le secteur côtier situé au large de la Loire et de la Vilaine, en termes (i) de fréquence de ces épisodes, (ii) d’abondance et (iii) de localisation des zones à risque. Action 1 : Amélioration du recensement des eaux vertes à L. chlorophorum Action 2 : Optimisation de l’estimation des abondances de L. chlorophorum Action 3 : Identification des zones à risque au large de la Loire et de la Vilaine. %G eng %U https://archimer.ifremer.fr/doc/00724/83598/ %0 Journal Article %J Geochemistry, Geophysics, Geosystems %D 2020 %T Li partitioning into coccoliths of Emiliania huxleyi : evaluating the general role of “vital effects” in explaining element partitioning in biogenic carbonates %A Langer, Gerald %A Sadekov, Aleksey %A Greaves, Mervyn %A Nehrke, Gernot %A Probert, Ian %A Misra, Sambuddha %A Thoms, Silke %K RCC3652 %X Abstract Emiliania huxleyi cells were grown in artificial seawater of different Li and Ca concentrations and coccolith Li/Ca ratios determined. Coccolith Li/Ca ratios were positively correlated to seawater Li/Ca ratios only if the seawater Li concentration was changed, not if the seawater Ca concentration was changed. This Li partitioning pattern of E. huxleyi was previously also observed in the benthic foraminifer Amphistegina lessonii and inorganically precipitated calcite. We argue that Li partitioning in both E. huxleyi and A. lessonii is dominated by a coupled transmembrane transport of Li and Ca from seawater to the site of calcification. We present a refined version of a recently proposed transmembrane transport model for Li and Ca. The model assumes that Li and Ca enter the cell via Ca channels, the Li flux being dependent on the Ca flux. While the original model features a linear function to describe the experimental data, our refined version uses a power function, changing the stoichiometry of Li and Ca. The version presented here accurately predicts the observed dependence of DLi on seawater Li/Ca ratios. Our data demonstrate that minor element partitioning in calcifying organisms is partly mediated by biological processes even if the partitioning behaviour of the calcifying organism is indistinguishable from that of inorganically precipitated calcium carbonate. %B Geochemistry, Geophysics, Geosystems %P 0–2 %8 jun %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GC009129 %R 10.1029/2020GC009129 %0 Journal Article %J Proceedings of the National Academy of Sciences %D 2018 %T Light color acclimation is a key process in the global ocean distribution of Synechococcus cyanobacteria %A Grébert, Théophile %A Doré, Hugo %A Partensky, Frédéric %A Farrant, Gregory K. %A Boss, Emmanuel S. %A Picheral, Marc %A Guidi, Lionel %A Pesant, Stéphane %A Scanlan, David J. %A Wincker, Patrick %A Acinas, Silvia G. %A Kehoe, David M. %A Garczarek, Laurence %K 2018 %K RCC1016 %K RCC1017 %K RCC1018 %K RCC1020 %K RCC1023 %K RCC1027 %K RCC1030 %K RCC1031 %K rcc1084 %K RCC1085 %K RCC1086 %K RCC1087 %K RCC1096 %K RCC1097 %K RCC1649 %K RCC1661 %K RCC1688 %K RCC2032 %K RCC2033 %K RCC2035 %K RCC2319 %K RCC2366 %K RCC2368 %K RCC2369 %K RCC2370 %K RCC2372 %K RCC2373 %K RCC2374 %K RCC2375 %K RCC2376 %K RCC2378 %K RCC2379 %K rcc2380 %K RCC2381 %K rcc2382 %K RCC2383 %K RCC2384 %K RCC2385 %K RCC2415 %K RCC2432 %K RCC2433 %K RCC2434 %K RCC2435 %K RCC2436 %K RCC2437 %K RCC2438 %K RCC2457 %K RCC2525 %K RCC2526 %K RCC2527 %K RCC2528 %K RCC2529 %K RCC2530 %K RCC2532 %K RCC2533 %K RCC2534 %K RCC2536 %K RCC2553 %K RCC2554 %K RCC2555 %K RCC2556 %K RCC2567 %K RCC2568 %K RCC2569 %K RCC2570 %K RCC2571 %K RCC2673 %K rcc30 %K RCC3010 %K RCC3012 %K RCC3014 %K RCC307 %K RCC316 %K RCC318 %K RCC325 %K RCC326 %K RCC328 %K RCC37 %K RCC44 %K RCC46 %K RCC47 %K RCC515 %K rcc539 %K RCC542 %K RCC543 %K RCC550 %K RCC552 %K RCC553 %K rcc555 %K RCC556 %K RCC557 %K RCC558 %K RCC559 %K RCC62 %K RCC650 %K RCC66 %K rcc752 %K RCC753 %K RCC790 %K rcc791 %K RCC792 %K RCC793 %K RCC794 %K sbr?hyto?app %X Marine Synechococcus cyanobacteria are major contributors to global oceanic primary production and exhibit a unique diversity of photosynthetic pigments, allowing them to exploit a wide range of light niches. However, the relationship between pigment content and niche partitioning has remained largely undetermined so far due to the lack of a single-genetic marker resolving all pigment types (PT). Here, we developed a novel and robust method based on three distinct marker genes to estimate the relative abundance of all Synechococcus PTs from metagenomes. Analysis of the Tara Oceans dataset allowed us to unveil for the first time the global distribution of Synechococcus PTs and to decipher their realized environmental niches. Green-light specialists (PT 3a) dominated in warm, green equatorial waters, whereas blue-light specialists (PT 3c) were particularly abundant in oligotrophic areas. Type IV chromatic acclimaters (CA4-A/B), which are able to dynamically modify their light absorption properties to maximally absorb green or blue light, were unexpectedly the most abundant PT in our dataset and predominated at depth and high latitudes. We also identified local populations in which CA4 might be inactive due to the lack of specific CA4 genes, notably in warm high nutrient low chlorophyll areas. Major ecotypes within clades I-IV and CRD1 were preferentially associated with a particular PT, while others exhibited a wide range of PTs. Altogether, this study brings unprecedented insights into the ecology of Synechococcus PTs and highlights the complex interactions between vertical phylogeny, pigmentation and environmental parameters that shape Synechococcus populations and evolution. %B Proceedings of the National Academy of Sciences %V in press %P 201717069 %8 feb %G eng %U http://www.pnas.org/lookup/doi/10.1073/pnas.1717069115 %R 10.1073/pnas.1717069115 %0 Journal Article %J PeerJ %D 2018 %T Linking pangenomes and metagenomes: the Prochlorococcus metapangenome %A Delmont, Tom O. %A Eren, A. Murat %K RCC156 %K RCC158 %K rcc162 %K RCC269 %K RCC278 %K rcc296 %K RCC3377 %K RCC407 %X Pangenomes offer detailed characterizations of core and accessory genes found in a set of closely related microbial genomes, generally by clustering genes based on sequence homology. In comparison, metagenomes facilitate highly resolved investigations of the relative distribution of microbial genomes and individual genes across environments through read recruitment analyses. Combining these complementary approaches can yield unique insights into the functional basis of microbial niche partitioning and fitness, however, advanced software solutions are lacking. Here we present an integrated analysis and visualization strategy that provides an interactive and reproducible framework to generate pangenomes and to study them in conjunction with metagenomes. To investigate its utility, we applied this strategy to a Prochlorococcus pangenome in the context of a large-scale marine metagenomic survey. The resulting Prochlorococcus metapangenome revealed remarkable differential abundance patterns between very closely related isolates that belonged to the same phylogenetic cluster and that differed by only a small number of gene clusters in the pangenome. While the relationships between these genomes based on gene clusters correlated with their environmental distribution patterns, phylogenetic analyses using marker genes or concatenated single-copy core genes did not recapitulate these patterns. The metapangenome also revealed a small set of core genes that mostly occurred in hypervariable genomic islands of the Prochlorococcus populations, which systematically lacked read recruitment from surface ocean metagenomes. Notably, these core gene clusters were all linked to sugar metabolism, suggesting potential benefits to Prochlorococcus from a high sequence diversity of sugar metabolism genes. The rapidly growing number of microbial genomes and increasing availability of environmental metagenomes provide new opportunities to investigate the functioning and the ecology of microbial populations, and metapangenomes can provide unique insights for any taxon and biome for which genomic and sufficiently deep metagenomic data are available. %B PeerJ %V 6 %P e4320 %G eng %U https://peerj.com/articles/4320 %R 10.7717/peerj.4320 %0 Journal Article %J Protist %D 2012 %T Lotharella reticulosa sp. nov.: A highly reticulated network forming chlorarachniophyte from the mediterranean sea %A Ota, Shuhei %A Vaulot, Daniel %K Chlorarachniophytes %K Lotharella %K Mediterranean Sea %K RCC375 %K RCC376 %K Taxonomy. %X A new chlorarachniophyte Lotharella reticulosa sp. nov. is described from a culture isolated from the Mediterranean Sea. This strain is maintained as strain RCC375 at the Roscoff Culture Collection, France. This species presents a multiphasic life cycle: vegetative cells of this species were observed to be coccoid, but amoeboid cells with filopodia and globular suspended cells were also present in the life cycle, both of which were not dominant phases. Flagellate cells were also observed but remained very rare in culture. The vegetative cells were 9-16 ??m in diameter and highly vacuolated, containing several green chloroplasts with a projecting pyrenoid, mitochondria, and a nucleus. The chloroplast was surrounded by four membranes possessing a nucleomorph in the periplastidial compartment near the pyrenoid base. According to ultrastructural observations of the pyrenoid and nucleomorph, the present species belongs to the genus Lotharella in the phylum Chlorarachniophyta. This taxonomic placement is consistent with the molecular phylogenetic trees of the 18S rRNA gene and ITS sequences. This species showed a unique colonization pattern. Clusters of cells extended cytoplasmic strands radially. Then, amoeboid cells being born proximately moved distally along the cytoplasmic strand like on a "railway track" Subsequently the amoeboid cell became coccoid near the strand. In this way, daughter cells were dispersed evenly on the substratum. We also observed that the present species regularly formed a structure of filopodial nodes in mid-stage and later-stage cultures, which is a novel phenotype in chlorarachniophytes. The unique colonization pattern and other unique features demonstrate that RCC375 is a new chlorarachniophyte belonging to genus Lotharella, which we describe as Lotharella reticulosa sp. nov. ?? 2011 Elsevier GmbH. %B Protist %V 163 %P 91–104 %G eng %0 Journal Article %J Plant Physiology %D 2011 %T Light history influences the response of the marine cyanobacterium Synechococcus sp. WH7803 to oxidative stress %A Blot, N %A Mella-Flores, D %A Six, C %A Lecorguille, G %A Boutte, C %A Peyrat, A %A Monnier, A %A Ratin, M %A Gourvil, P %A Campbell, D A %A Garczarek, L %K 2011 %K rcc %K SBR$_\textrmP$hyto$_\textrmP$PM %K sbr?hyto?app %X Marine Synechococcus undergo a wide range of environmental stressors, especially high and variable irradiance, which may induce oxidative stress through the generation of reactive oxygen species (ROS). While light and ROS could act synergistically on the impairment of photosynthesis, inducing photodamage and inhibiting photosystem II repair, acclimation to high irradiance is also thought to confer resistance to other stressors. To identify the respective roles of light and ROS in the photoinhibition process and detect a possible light-driven tolerance to oxidative stress, we compared the photophysiological and transcriptomic responses of Synechococcus sp. WH7803 acclimated to low (LL) or high light (HL) to oxidative stress, induced by hydrogen peroxide (H2O2) or methylviologen. While photosynthetic activity was much more affected in HL than in LL cells, only HL cells were able to recover growth and photosynthesis after addition of 25 microM H2O2. Depending upon light conditions and H2O2 concentration, the latter oxidizing agent induced photosystem II inactivation through both direct damages to the reaction centres and inhibition of its repair cycle. Although the global transcriptome response appeared similar in LL and HL cells, some processes were specifically induced in HL cells that seemingly helped them withstand oxidative stress, including enhancement of photoprotection and ROS detoxification, repair of ROS-driven damages and regulation of redox state. Detection of putative LexA binding sites allowed the identification of the putative LexA regulon, which was down-regulated in HL compared to LL cells, but up-regulated by oxidative stress under both growth irradiances. %B Plant Physiology %V 156 %P 1934–1954 %G eng %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=21670225 %0 Journal Article %J Applied and Environmental Microbiology %D 2009 %T Light-dependent transcriptional regulation of genes of biogeochemical interest in the diploid and haploid life cycle stages of Emiliania huxleyi %A Richier, S %A Kerros, M E %A de Vargas, C %A Haramaty, L %A Falkowski, P G %A Gattuso, J P %K 2009 %K rcc %K SBR$_\textrmP$hyto$_\textrmE$PPO %K sbr?hyto?ppo %X The expression of genes of biogeochemical interest in calcifying and noncalcifying life stages of the coccolithophore Emiliania huxleyi was investigated. Transcripts potentially involved in calcification were tested through a light-dark cycle. These transcripts were more abundant in calcifying cells and were upregulated in the light. Their application as potential candidates for in situ biogeochemical proxies is also suggested. %B Applied and Environmental Microbiology %V 75 %P 3366–3369 %G eng %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19304825 %R 10.1128/aem.02737-08 %0 Journal Article %J PLoS ONE %D 2008 %T Life-cycle and genome of OtV5, a large DNA virus of the pelagic marine unicellular green alga ¡i¿Ostreococcus tauri¡/i¿ %A Derelle, Evelyne %A Ferraz, Conchita %A Escande, Marie-Line %A Eychenié, Sophie %A Cooke, Richard %A Piganeau, Gwenael %A Desdevises, Yves %A Bellec, Laure %A Moreau, Hervé %A Grimsley, Nigel %K rcc %X Large DNA viruses are ubiquitous, infecting diverse organisms ranging from algae to man, and have probably evolved from an ancient common ancestor. In aquatic environments, such algal viruses control blooms and shape the evolution of biodiversity in phytoplankton, but little is known about their biological functions. We show that Ostreococcus tauri, the smallest known marine photosynthetic eukaryote, whose genome is completely characterized, is a host for large DNA viruses, and present an analysis of the life-cycle and 186,234 bp long linear genome of OtV5. OtV5 is a lytic phycodnavirus which unexpectedly does not degrade its host chromosomes before the host cell bursts. Analysis of its complete genome sequence confirmed that it lacks expected site-specific endonucleases, and revealed the presence of 16 genes whose predicted functions are novel to this group of viruses. OtV5 carries at least one predicted gene whose protein closely resembles its host counterpart and several other host-like sequences, suggesting that horizontal gene transfers between host and viral genomes may occur frequently on an evolutionary scale. Fifty seven percent of the 268 predicted proteins present no similarities with any known protein in Genbank, underlining the wealth of undiscovered biological diversity present in oceanic viruses, which are estimated to harbour 200Mt of carbon. %B PLoS ONE %V 3 %P e2250 %G eng %U http://dx.doi.org/10.1371/journal.pone.0002250 %R 10.1371/journal.pone.0002250 %0 Journal Article %J Journal of Phycology %D 2007 %T Light and electron microscope observations of Algirosphaera robusta (Prymnesiophyceae) %A Probert, I %A Fresnel, J %A Billard, C %A Geisen, Markus %A Young, J R %K 2007 %K rcc %K SBR$_\textrmP$hyto$_\textrmE$PPO %B Journal of Phycology %V 43 %P 319–332 %G eng %R 10.1111/j.1529-8817.2007.00324.x