@article {parsy_selection_2023, title = {Selection of photosynthetic microorganisms grown in artificial saline industrial effluents with liquid digestate: From screening to consortium cultures}, journal = {Algal Research}, year = {2023}, month = {mar}, pages = {103061}, abstract = {The objective of this study was to determine the feasibility of using saline industrial streams as a culture medium to grow microalgae and cyanobacteria. Experiments were performed to determine the extent of the growth in artificial saline produced water and aquifer water supplemented with liquid digestate. Tests were performed in 96-wells microplates. Media were composed with different proportion of saline artificial produced water or aquifer water supplemented with 5\% v/v liquid digestate (final concentrations: 149{\textendash}195 mgN{\textperiodcentered}L-1, 1.5{\textendash}2.7 mgP{\textperiodcentered}L-1). Media were completed to 100 \% with artificial seawater, corresponding to final salinities of 40, 70 and 100 g{\textperiodcentered}L-1. D. salina, N. oceanica and T. suecica showed the best growth rates. They were selected to perform mixed cultures in 80 mL tubes in the same culture media. Population evolutions were followed for 19 days. Depending on salinity and industrial effluent used, different species became predominant over the two others (N. oceanica, T. suecica and D. salina. at 40, 70 and 100 g{\textperiodcentered}L-1, respectively). It appears that mixed culture is a good solution to have a biomass production during a culture process where the culture media will evolve in terms of salinity and composition.}, keywords = {Aquifer water, cyanobacteria, Liquid digestate, Microalgae, Produced water, RCC4223, RCC537, rcc752}, issn = {2211-9264}, doi = {10.1016/j.algal.2023.103061}, url = {https://www.sciencedirect.com/science/article/pii/S2211926423000942}, author = {Parsy, Aur{\'e}lien and Sambusiti, Cecilia and Baldoni-Andrey, Patrick and P{\'e}ri{\'e}, Fr{\'e}d{\'e}ric and Guyoneaud, R{\'e}my} } @article {dedman_shotgun_2023, title = {Shotgun proteomics reveals temperature-dependent regulation of major nutrient metabolism in coastal Synechococcus sp. WH5701}, journal = {Algal Research}, year = {2023}, month = {oct}, pages = {103279}, abstract = {Marine cyanobacteria are major contributors to the oceanic carbon sink and are predicted to increase in numbers in the future warmed ocean. As a result, the influence of marine cyanobacteria on marine biogeochemical cycling will likely be enhanced. Associated with elevations in temperature the ocean will undergo increased stratification, reducing supply of essential nutrients to upper phototrophic layers. It is therefore critical that we resolve the manners by which cyanobacteria respond to variations in temperature, and consequences for major nutrient metabolism which may ultimately direct global biogeochemistry and trophic transfer. In this study we use the coastal Synechococcus sp. WH5701 to examine proteomic alterations in major nutrient (C, N and P) metabolic pathways following exposure to varying temperature. In response to temperature treatments, Synechococcus displayed higher rates of growth and photosynthetic efficiency when temperatures were raised from 17 {\textdegree}C to 23 {\textdegree}C and 28 {\textdegree}C, associated with a significant \textasciitilde30{\textendash}40 \% alteration in the cellular proteome. As temperatures increased, proteomic investment towards photosynthetic machinery appeared up-regulated, whilst abundance of RuBisCO was reduced, associated with an apparent alteration in CCM composition and carbon metabolism. N demand appeared to increase in-line with temperature, associated with alterations in the GS-GOGAT pathway, likely due to increased demand for and efficiency of protein synthesis. In contrast, P demand at the highest temperature appeared reduced as investment in the ribosome declines due to improved translation efficiency, whilst luxury P-storage appeared a feature of growth at low temperature. It appears likely that as seawater temperatures rise under ocean warming, the biochemical composition of cyanobacteria will be altered, increasing cellular C- and N- to P ratios, ultimately impacting upon their contribution to oceanic biogeochemical cycling.}, keywords = {climate change, Ocean warming, phytoplankton, Proteomics: Marine biogeochemistry, rcc1084}, issn = {2211-9264}, doi = {10.1016/j.algal.2023.103279}, url = {https://www.sciencedirect.com/science/article/pii/S2211926423003120}, author = {Dedman, Craig J. and Barton, Samuel and Fournier, Marjorie and Rickaby, Rosalind E. M.} } @article {klintzsch_stable_2023, title = {Stable Carbon Isotope Signature of Methane Released from Phytoplankton}, journal = {Geophysical Research Letters}, year = {2023}, month = {feb}, abstract = {Aquatic ecosystems play an important role in global methane cycling and many field studies have reported methane supersaturation in the oxic surface mixed layer (SML) of the ocean and in the epilimnion of lakes. The origin of methane formed under oxic condition is hotly debated and several pathways have recently been offered to explain the {\textquoteleft}methane paradox{\textquoteright}. In this context, stable isotope measurements have been applied to constrain methane sources in supersaturated oxygenated waters. Here we present stable carbon isotope signatures for six widespread marine phytoplankton species, three haptophyte algae and three cyanobacteria, incubated under laboratory conditions. The observed isotopic patterns implicate that methane formed by phytoplankton might be clearly distinguished from methane produced by methanogenic archaea. Comparing results from phytoplankton experiments with isotopic data from field measurements, suggests that algal and cyanobacterial populations may contribute substantially to methane formation observed in the SML of oceans and lakes.}, keywords = {RCC1216, ⛔ No DOI found}, doi = {10.22541/essoar.167689993.32180072/v1}, url = {https://essopenarchive.org/users/587513/articles/625160-stable-carbon-isotope-signature-of-methane-released-from-phytoplankton?commit=633a121ee07c48e6c59ffeca06fd5d5ebe1df4d4}, author = {Klintzsch, Thomas and Geisinger, Hannah and Wieland, Anna and Langer, Gerald and Nehrke, Gernot and Bizic, Mina and Greule, Markus and Lenhart, Katharina and Borsch, Christian and Schroll, Moritz and Keppler, Frank} } @article {zhang_stimulating_2023, title = {Stimulating and toxic effect of chromium on growth and photosynthesis of a marine chlorophyte}, journal = {New Phytologist}, volume = {n/a}, number = {n/a}, year = {2023}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/nph.19376}, abstract = {Marine phytoplankton can interchange trace metals in various biochemical functions, particularly under metal-limiting conditions. Here, we investigate the stimulating and toxicity effect of chromium (Cr) on a marine Chlorophyceae Osetreococcus tauri under Fe-replete and Fe-deficient conditions. We determined the growth, photosynthesis, and proteome expressions of Osetreococcus tauri cultured under different Cr and Fe concentrations. In Fe-replete conditions, the presence of Cr(VI) stimulated significantly the growth rate and the maximum yield of photochemistry of photosystem II (Fv/Fm) of the phytoplankton, while the functional absorption cross-section of photosystem II (σPSII) did not change. Minor additions of Cr(VI) partially rescued phytoplankton growth under Fe-limited conditions. Proteomic analysis of this alga grown in Fe-replete normal and Fe-replete with Cr addition media (10 μM Cr) showed that the presence of Cr significantly decreased the expression of phosphate-transporting proteins and photosynthetic proteins, while increasing the expression of proteins related to carbon assimilation. Cr can stimulate the growth and photosynthesis of O. tauri, but the effects are dependent on both the Cr(VI) concentration and the availability of Fe. The proteomic results further suggest that Cr(VI) addition might significantly increase starch production and carbon fixation.}, keywords = {chromium, Photosynthesis, phytoplankton, proteomics, RCC1, RCC1242, trace metal}, issn = {1469-8137}, doi = {10.1111/nph.19376}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/nph.19376}, author = {Zhang, Qiong and Charles, Philip D. and Bendif, El Mahdi and Hester, Svenja S. and Mohammad, Shabaz and Rickaby, Rosalind E. M.} } @article {de_la_broise_scale-up_2022, title = {Scale-Up to Pilot of a Non-Axenic Culture of Thraustochytrids Using Digestate from Methanization as Nitrogen Source}, journal = {Marine Drugs}, volume = {20}, number = {8}, year = {2022}, month = {aug}, pages = {499}, abstract = {The production of non-fish based docosahexaenoic acid (DHA) for feed and food has become a critical need in our global context of over-fishing. The industrial-scale production of DHA{\textendash}rich Thraustochytrids could be an alternative, if costs turned out to be competitive. In order to reduce production costs, this study addresses the feasibility of the non-axenic (non-sterile) cultivation of Aurantiochytrium mangrovei on industrial substrates (as nitrogen and mineral sources and glucose syrup as carbon and energy sources), and its scale-up from laboratory (250 mL) to 500 L cultures. Pilot-scale reactors were airlift cylinders. Batch and fed-batch cultures were tested. Cultures over 38 to 62 h achieved a dry cell weight productivity of 3.3 to 5.5 g.L-1.day-1, and a substrate to biomass yield of up to 0.3. DHA productivity ranged from 10 to 0.18 mg.L-1.day-1. Biomass productivity appears linearly related to oxygen transfer rate. Bacterial contamination of cultures was low enough to avoid impacts on fatty acid composition of the biomass. A specific work on microbial risks assessment (in supplementary files) showed that the biomass can be securely used as feed. However, to date, there is a law void in EU legislation regarding the recycling of nitrogen from digestate from animal waste for microalgae biomass and its usage in animal feed. Overall, the proposed process appears similar to the industrial yeast production process (non-axenic heterotrophic process, dissolved oxygen supply limiting growth, similar cell size). Such similarity could help in further industrial developments.}, keywords = {RCC893}, issn = {1660-3397}, doi = {10.3390/md20080499}, url = {https://www.mdpi.com/1660-3397/20/8/499}, author = {de la Broise, Denis and Ventura, Mariana and Chauchat, Luc and Guerreiro, Maurean and Michez, Teo and Vinet, Thibaud and Gautron, Nicolas and Le Grand, Fabienne and Bideau, Antoine and Go{\"\i}c, Nelly Le and Bidault, Adeline and Lambert, Christophe and Soudant, Philippe} } @article {croteau_shifts_2022, title = {Shifts in growth light optima among diatom species support their succession during the spring bloom in the Arctic}, journal = {Journal of Ecology}, volume = {n/a}, number = {n/a}, year = {2022}, note = {_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2745.13874}, abstract = {1. Diatoms of the Arctic Ocean annually experience extreme changes of light environment linked to photoperiodic cycles and seasonal variations of the snow and sea-ice cover extent and thickness which attenuate light penetration in the water column. Arctic diatom communities exploit this complex seasonal dynamic through a well-documented species succession during spring, beginning in sea-ice and culminating in massive phytoplankton blooms underneath sea-ice and in the marginal ice zone. The pattern of diatom taxa sequentially dominating this succession is relatively well conserved interannually, and taxonomic shifts seem to align with habitat transitions. 2. To understand whether differential photoadaptation strategies among diatom taxa explain these recurring succession sequences, we coupled lab experiments with field work in Baffin Bay at 67.5{\textdegree}N. Based on field data, we selected five diatom species typical of different ecological niches and measured their growth rates under light intensity ranges representative of their natural habitats. To characterize their photoacclimative responses, we sampled pigments and total particulate carbon, and conducted 14C-uptake photosynthesis response curves and variable fluorescence measurements. 3. We documented a gradient in species respective light intensity for maximal growth suggesting divergent light response plasticity, which for the most part align with species sequential dominance. Other photophysiological parameters supported this ecophysiological framing, although contrasts were always clear only between succession endmembers, Nitzschia frigida and Chaetoceros neogracilis. To validate that these photoacclimative responses are representative of in situ dynamics, we compared them to the chlorophyll a-specific light-limited slope (α*) and saturated rate of photosynthesis (P*M), monitored in Baffin Bay on sea-ice and planktonic communities. This complementary approach confirmed that unusual responses in α* and P*M as a function of light history intensity are similar between sentinel sympagic species N. frigida and natural ice-core communities. While no light-history-dependent trends were observed in planktonic communities, their α* and P*M values were in the range of measurements from our monospecific cultures. 4. Synthesis. Our results suggest that Arctic diatoms species photoadaptation strategy is tuned to the light environment of the habitats in which they dominate and indeed drives the seasonal taxonomic succession.}, keywords = {Arctic Ocean, diatoms, Ecophysiology, photoacclimation, photoadaptation, primary production, RCC2046, RCC2278, seasonal species succession, spring bloom}, issn = {1365-2745}, doi = {10.1111/1365-2745.13874}, url = {http://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.13874}, author = {Croteau, D. and Lacour, T. and Schiffrine, N. and Morin, P.-I. and Forget, M.-H. and Bruyant, F. and Ferland, J. and Lafond, A. and Campbell, D. A. and Tremblay, J.-E. and Babin, M. and Lavaud, J.} } @article {leblond_sterols_2022, title = {Sterols of Testudodinium testudo (formerly Amphidinium testudo): Production of the Δ8(14) sterol gymnodinosterol and chemotaxonomic relationship to the Kareniaceae}, journal = {Journal of Eukaryotic Microbiology}, volume = {n/a}, number = {n/a}, year = {2022}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jeu.12929}, pages = {e12929}, abstract = {Testudodinium testudo is a peridinin-containing dinoflagellate recently renamed from Amphidinium testudo. While T. testudo has been shown via phylogenetic analysis of small subunit ribosomal RNA genes to reside in a clade separate from the genus Amphidinium, it does possess morphological features similar to Amphidinium sensu stricto. Previous studies of Amphidinium carterae and Amphidinium corpulentum have found the sterols to be enriched in Δ8(14) sterols, such as 4α-methyl-5α-ergosta-8(14),24(28)-dien-3β-ol (amphisterol), uncommon to most other dinoflagellate taxa and thus considered possible biomarkers for the genus Amphidinium. Here, we provide an examination of the sterols of T. testudo and show they are dominated not by amphisterol, but rather by a different Δ8(14) sterol, (24R)-4α-methyl-5α-ergosta-8(14),22-dien-3β-ol (gymnodinosterol), previously thought to be a major sterol only within the Kareniaceae genera Karenia, Karlodinium, and Takayama. Also found to be present at low levels were 4α-methyl-5α-ergosta-8,14,22-trien-3β-ol, a sterol previously observed in Karenia brevis to be an intermediate in the production of gymnodinosterol, and cholesterol, a sterol common to many other dinoflagellates. The presence of gymnodinosterol in T. testudo is the first report of this sterol as the sole major sterol in a dinoflagellate outside of the Kareniaceae. The implication of this chemotaxonomic relationship to the Kareniaceae is discussed.}, keywords = {Amphidinium, Dinoflagellate, Dinophyceae, lipid, RCC1981, sterol, Testudodinium}, issn = {1550-7408}, doi = {10.1111/jeu.12929}, url = {http://onlinelibrary.wiley.com/doi/abs/10.1111/jeu.12929}, author = {Leblond, Jeffrey D. and Elkins, Lindsey C. and Sabir, Kyra and Graeff, Jori E.} } @article {castillo_seasonal_2021, title = {Seasonal dynamics of natural Ostreococcus viral infection at the single cell level using VirusFISH}, journal = {Environmental Microbiology}, volume = {n/a}, number = {n/a}, year = {2021}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/1462-2920.15504}, abstract = {Ostreococcus is a cosmopolitan marine genus of phytoplankton found in mesotrophic and oligotrophic waters, and the smallest free-living eukaryotes known to date, with a cell diameter close to 1 μm. Ostreococcus has been extensively studied as a model system to investigate viral{\textendash}host dynamics in culture, yet the impact of viruses in naturally occurring populations is largely unknown. Here, we used Virus Fluorescence in situ Hybridization (VirusFISH) to visualize and quantify viral-host dynamics in natural populations of Ostreococcus during a seasonal cycle in the central Cantabrian Sea (Southern Bay of Biscay). Ostreococcus were predominantly found during summer and autumn at surface and 50 m depth, in coastal, mid-shelf and shelf waters, representing up to 21\% of the picoeukaryotic communities. Viral infection was only detected in surface waters, and its impact was variable but highest from May to July and November to December, when up to half of the population was infected. Metatranscriptomic data available from the mid-shelf station unveiled that the Ostreococcus population was dominated by the species O. lucimarinus. This work represents a proof of concept that the VirusFISH technique can be used to quantify the impact of viruses on targeted populations of key microbes from complex natural communities. This article is protected by copyright. All rights reserved.}, keywords = {RCC2590, RCC4221, RCC809}, issn = {1462-2920}, doi = {10.1111/1462-2920.15504}, url = {http://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1462-2920.15504}, author = {Castillo, Yaiza M. and Forn, Irene and Yau, Sheree and Mor{\'a}n, Xos{\'e} Anxelu G. and Alonso-S{\'a}ez, Laura and Arandia-Gorostidi, N{\'e}stor and Vaqu{\'e}, Dolors and Sebasti{\'a}n, Marta} } @article {das_single_2021, title = {Single toxicity of arsenic and combined trace metal exposure to a microalga of ecological and commercial interest: Diacronema lutheri}, journal = {Chemosphere}, year = {2021}, pages = {132949}, abstract = {Eco-toxicological assays with species of economic interest such as Diacronema lutheri are essential for industries that produce aquaculture feed, natural food additives and also in drug developing industries. Our study involved the exposure of a single and combined toxicity of arsenic (As V) to D. lutheri for the entire algal growth phase and highlighted that a combined exposure of As V with other essential (Copper, Cu; Nickel, Ni) and non-essential (Cadmium, Cd; Lead, Pb) trace metals reduced significantly the cell number, chlorophyll a content, and also significantly increased the de-epoxidation ratio (DR) as a stress response when compared to the single toxicity of As V. Arsenic, as one of the ubiquitous trace metal and an active industrial effluent is reported to have an increased bio-concentration factor when in mixture with other trace metals in this study. In the combined exposure, the concentration of total As bio-accumulated by D. lutheri was higher than in the single exposure. Hence, polluted areas with the prevalence of multiple contaminants along with the highly toxic trace metals like As can impose a greater risk to the exposed organisms that may get further bio-magnified in the food chain. Our study highlights the consequences and the response of D. lutheri in terms of contamination from single and multiple trace metals in order to obtain a safer biomass production for the growing need of natural derivatives.}, keywords = {Arsenic, bioaccumulation, Bioconcentration factor, Chlorophyll, de-epoxidation ratio, RCC1537, Trace metals mixture}, issn = {0045-6535}, doi = {10.1016/j.chemosphere.2021.132949}, url = {https://www.sciencedirect.com/science/article/pii/S0045653521034214}, author = {Das, Shagnika and Gevaert, Fran{\c c}ois and Ouddane, Baghdad and Duong, Gwendoline and Souissi, Sami} } @article {graeff_sterol_2021, title = {Sterol Composition of the Peridinioid Dinoflagellate Zooxanthella nutricula, A Symbiont of Polycystine Radiolarians}, journal = {Protist}, volume = {172}, number = {3}, year = {2021}, month = {jul}, pages = {125817}, abstract = {Some dinoflagellates, such as Symbiodinium, are able to form symbiotic relationships with larger marine organisms. An important aspect of dinoflagellate symbiosis involves the exchange of lipids, namely sterols, from the symbiont to the host. Much research has explored the lipid biochemistry of the symbiotic relationship between cnidarians and Symbiodinium dinoflagellates. However, no research has addressed the sterol biochemistry of the symbiosis between radiolarians and dinoflagellates such as Zooxanthella nutricula. To this end, we have provided the first sterol characterization of Z. nutricula isolated from a spumellarian polycystine radiolarian. Fifteen sterols and one steroidal ketone were observed where the major sterol identified was C27 22-dehydrocholesterol, which does not tend to be a dominant sterol among dinoflagellates, including closely related peridinioid species in the genus Heterocapsa. However, C30 dinosterol and dinostanol were major sterols in both Z. nutricula and Heterocapsa spp., thus indicating common sterols between closely related taxa. Major sterols of the distantly related genus Symbiodinium, a symbiont of foraminifera and cnidarians, have included C27 cholesterol and C30 gorgosterol, whereas in Z. nutricula these sterols were minor and absent, respectively. Our results indicate potentially different sterol pools available to cnidarian and radiolarian symbiont hosts during their respective relationships with symbiotic dinoflagellates.}, keywords = {Dinoflagellate, lipid, Peridiniales, Radiolaria, rcc, RCC3387, sterol}, issn = {1434-4610}, doi = {10.1016/j.protis.2021.125817}, url = {https://www.sciencedirect.com/science/article/pii/S1434461021000262}, author = {Graeff, Jori E. and Leblond, Jeffrey D.} } @article {gebuhr_strain-specific_2021, title = {Strain-specific morphological response of the dominant calcifying phytoplankton species Emiliania huxleyi to salinity change}, journal = {PLOS ONE}, volume = {16}, number = {2}, year = {2021}, note = {Publisher: Public Library of Science}, month = {feb}, pages = {e0246745}, abstract = {The future physiology of marine phytoplankton will be impacted by a range of changes in global ocean conditions, including salinity regimes that vary spatially and on a range of short- to geological timescales. Coccolithophores have global ecological and biogeochemical significance as the most important calcifying marine phytoplankton group. Previous research has shown that the morphology of their exoskeletal calcified plates (coccoliths) responds to changing salinity in the most abundant coccolithophore species, Emiliania huxleyi. However, the extent to which these responses may be strain-specific is not well established. Here we investigated the growth response of six strains of E. huxleyi under low (ca. 25) and high (ca. 45) salinity batch culture conditions and found substantial variability in the magnitude and direction of response to salinity change across strains. Growth rates declined under low and high salinity conditions in four of the six strains but increased under both low and high salinity in strain RCC1232 and were higher under low salinity and lower under high salinity in strain PLYB11. When detailed changes in coccolith and coccosphere size were quantified in two of these strains that were isolated from contrasting salinity regimes (coastal Norwegian low salinity of ca. 30 and Mediterranean high salinity of ca. 37), the Norwegian strain showed an average 26\% larger mean coccolith size at high salinities compared to low salinities. In contrast, coccolith size in the Mediterranean strain showed a smaller size trend (11\% increase) but severely impeded coccolith formation in the low salinity treatment. Coccosphere size similarly increased with salinity in the Norwegian strain but this trend was not observed in the Mediterranean strain. Coccolith size changes with salinity compiled for other strains also show variability, strongly suggesting that the effect of salinity change on coccolithophore morphology is likely to be strain specific. We propose that physiological adaptation to local conditions, in particular strategies for plasticity under stress, has an important role in determining ecotype responses to salinity.}, keywords = {Calcification, Carbonates, Ecophysiology, Marine ecology, Marine geology, Morphometry, Paleoclimatology, rcc1210, RCC1232, rcc1824, rcc868, RCC904, salinity}, issn = {1932-6203}, doi = {10.1371/journal.pone.0246745}, url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0246745}, author = {Geb{\"u}hr, Christina and Sheward, Rosie M. and Herrle, Jens O. and Bollmann, J{\"o}rg} } @article {decelle_subcellular_2021, title = {Subcellular architecture and metabolic connection in the planktonic photosymbiosis between Collodaria (radiolarians) and their microalgae}, journal = {bioRxiv}, year = {2021}, note = {Company: Cold Spring Harbor Laboratory Distributor: Cold Spring Harbor Laboratory Label: Cold Spring Harbor Laboratory Section: New Results Type: article}, pages = {2021.03.13.435225}, abstract = {Photosymbiosis is widespread and ecologically important in the oceanic plankton but remains poorly studied. Here, we used multimodal subcellular imaging to investigate the photosymbiosis between colonial Collodaria and their microalga dinoflagellate (Brandtodinium) collected in surface seawaters. We showed that this symbiosis is a very dynamic system whereby symbionts interact with different host cells via extracellular vesicles within the {\textquotedblleft}greenhouse-like{\textquotedblright} colony. 3D electron microscopy revealed that the volume of the photosynthetic apparatus (plastid and pyrenoid) of the microalgae increased in symbiosis compared to free-living while the mitochondria volume was similar. Stable isotope probing coupled with NanoSIMS showed that carbon and nitrogen were assimilated and stored in the symbiotic microalga in starch granules and purine crystals, respectively. Nitrogen was also allocated to the algal nucleus (nucleolus). After 3 hours, low 13C and 15N transfer was detected in the host Golgi. Metal mapping revealed that intracellular iron concentration was similar in free-living and symbiotic microalgae (ca 40 ppm) and two-fold higher in the host, whereas copper concentration increased in symbiotic microalgae (up to 6900 ppm) and was detected in the host cell and extracellular vesicles. Sulfur mapping also pinpointed the importance of this nutrient for the algal metabolism. This study, which revealed subcellular changes of the morphology and nutrient homeostasis in symbiotic microalgae, improves our understanding on the metabolism of this widespread and abundant oceanic symbiosis and paves the way for more studies to investigate the metabolites exchanged.}, doi = {10.1101/2021.03.13.435225}, url = {https://www.biorxiv.org/content/10.1101/2021.03.13.435225v1}, author = {Decelle, Johan and Veronesi, Giulia and LeKieffre, Charlotte and Gallet, Benoit and Chevalier, Fabien and Stryhanyuk, Hryhoriy and Marro, Sophie and Ravanel, St{\'e}phane and Tucoulou, R{\'e}mi and Schieber, Nicole and Finazzi, Giovanni and Schwab, Yannick and Musat, Niculina} } @article {Hepach2020, title = {Senescence as the main driver of iodide release from a diverse range of marine phytoplankton}, journal = {Biogeosciences}, volume = {17}, number = {9}, year = {2020}, note = {tex.mendeley-tags: RC4512,RCC1164,RCC1210,RCC1318,RCC1725,RCC2366,RCC4024,RCC4208,RCC4560}, month = {may}, pages = {2453{\textendash}2471}, keywords = {RCC1164, rcc1210, RCC1318, RCC1725, RCC2366, RCC4024, RCC4208, RCC4512, RCC4560}, issn = {1726-4189}, doi = {10.5194/bg-17-2453-2020}, url = {https://www.biogeosciences.net/17/2453/2020/}, author = {Hepach, Helmke and Hughes, Claire and Hogg, Karen and Collings, Susannah and Chance, Rosie} } @article {Meyer2020, title = {Sr in coccoliths of Scyphosphaera apsteinii: Partitioning behavior and role in coccolith morphogenesis}, journal = {Geochimica et Cosmochimica Acta}, volume = {285}, year = {2020}, note = {Publisher: Elsevier Ltd tex.mendeley-tags: RCC1456}, month = {sep}, pages = {41{\textendash}54}, abstract = {Coccolithophores are important contributors to global calcium carbonate through their species-specific production of calcite coccoliths. Nannofossil coccolith calcite remains an important tool for paleoreconstructions through geochemical analysis of isotopic and trace element incorporation including Sr, which is a potential indicator of past surface ocean temperature and productivity. Scyphosphaera apsteinii (Zygodiscales) exhibits an unusually high Sr/Ca ratio and correspondingly high partitioning coefficient (DSr = 2.5) in their two morphologically distinct types of coccoliths: flat muroliths and barrel-like lopadoliths. Whether or not this reflects mechanistic differences in calcification compared to other coccolithophores is unknown. We therefore examined the possible role of Sr in S. apsteinii calcification by growing cells in deplete (0.33 mmol/mol Sr/Ca), ambient (9 mmol/mol Sr/Ca), and higher than ambient Sr conditions (36 and 72 mmol/mol Sr/Ca). The effects on growth, quantum efficiency of photosystem II (Fv/Fm), coccolith morphology, and calcite DSr were evaluated. No effect on S. apsteinii growth rate or Fv/Fm was observed when cells were grown in Sr/Ca between 0.33{\textendash}36 mmol/mol. However, at 72 mmol/mol Sr/Ca growth rate was significantly reduced, although Fv/Fm was unaffected. Reducing the Sr/Ca from ambient (9 mmol/mol) did not significantly alter the frequency of malformed and aberrant muroliths and lopadoliths, but at higher than ambient Sr/Ca conditions coccolith morphology was significantly disrupted. This implies that Sr is not a critical determining factor in normal coccolith calcite morphology in this dimorphic species. Using energy dispersive spectroscopy (EDS) we observed an increase in [Sr] and decrease in DSr of coccoliths as the Sr/Ca of the growth medium increased. Interestingly, muroliths had significantly lower Sr/Ca than lopadoliths at ambient and elevated [Sr], and lopadolith tips had lower Sr than bases in ambient conditions. In summary, the Sr fractionation behavior of S. apsteinii is distinct from other coccolithophores because of an unusually high DSr and inter- and intra-coccolith variability in Sr/Ca. These observations could be explained by mechanistic differences in the selectivity of the Ca2+ transport pathway or in the Sr-and Ca-binding capacity of organic components, such as polysaccharides associated with coccolithogenesis.}, keywords = {biomineralization, Calcification, coccolith, coccolithophore, Energy dispersive spectroscopy, Fractionation, RCC1456, Sr/Ca, Strontium, Trace element}, issn = {00167037}, doi = {10.1016/j.gca.2020.06.023}, author = {Meyer, Erin M. and Langer, Gerald and Brownlee, Colin and Wheeler, Glen L. and Taylor, Alison R.} } @article {Guyet2020, title = {Synergic effects of temperature and irradiance on the physiology of the marine synechococcus strain WH7803}, journal = {Frontiers in Microbiology}, volume = {11}, year = {2020}, note = {Publisher: Frontiers Media S.A. tex.mendeley-tags: RCC752}, month = {jul}, pages = {1707}, abstract = {Understanding how microorganisms adjust their metabolism to maintain their ability to cope with short-term environmental variations constitutes one of the major current challenges in microbial ecology. Here, the best physiologically characterized marine Synechococcus strain, WH7803, was exposed to modulated light/dark cycles or acclimated to continuous high-light (HL) or low-light (LL), then shifted to various stress conditions, including low (LT) or high temperature (HT), HL and ultraviolet (UV) radiations. Physiological responses were analyzed by measuring time courses of photosystem (PS) II quantum yield, PSII repair rate, pigment ratios and global changes in gene expression. Previously published membrane lipid composition were also used for correlation analyses. These data revealed that cells previously acclimated to HL are better prepared than LL-acclimated cells to sustain an additional light or UV stress, but not a LT stress. Indeed, LT seems to induce a synergic effect with the HL treatment, as previously observed with oxidative stress. While all tested shift conditions induced the downregulation of many photosynthetic genes, notably those encoding PSI, cytochrome b6/f and phycobilisomes, UV stress proved to be more deleterious for PSII than the other treatments, and full recovery of damaged PSII from UV stress seemed to involve the neo-synthesis of a fairly large number of PSII subunits and not just the reassembly of pre-existing subunits after D1 replacement. In contrast, genes involved in glycogen degradation and carotenoid biosynthesis pathways were more particularly upregulated in response to LT. Altogether, these experiments allowed us to identify responses common to all stresses and those more specific to a given stress, thus highlighting genes potentially involved in niche acclimation of a key member of marine ecosystems. Our data also revealed important specific features of the stress responses compared to model freshwater cyanobacteria.}, keywords = {light stress, marine cyanobacteria, rcc752, Synechococcus, temperature stress, transcriptomics, UV radiations}, issn = {1664302X}, doi = {10.3389/fmicb.2020.01707}, url = {www.frontiersin.org}, author = {Guyet, Ulysse and Nguyen, Ngoc A. and Dor{\'e}, Hugo and Haguait, Julie and Pittera, Justine and Conan, Ma{\"e}l and Ratin, Morgane and Corre, Erwan and Le Corguill{\'e}, Gildas and Brillet-Gu{\'e}guen, Loraine and Hoebeke, Mark and Six, Christophe and Steglich, Claudia and Siegel, Anne and Eveillard, Damien and Partensky, Fr{\'e}d{\'e}ric and Garczarek, Laurence} } @article {Derilus2020, title = {Synergism between the Black Queen effect and the proteomic constraint on genome size reduction in the photosynthetic picoeukaryotes}, journal = {Scientific Reports}, volume = {10}, number = {1}, year = {2020}, note = {Publisher: Springer US tex.mendeley-tags: RCC1110,RCC1116,RCC809}, pages = {8918}, keywords = {RCC1110, RCC1116, RCC809}, issn = {2045-2322}, doi = {10.1038/s41598-020-65476-1}, url = {http://dx.doi.org/10.1038/s41598-020-65476-1 http://www.nature.com/articles/s41598-020-65476-1}, author = {Derilus, D and Rahman, M Z and Pinero, F and Massey, S E} } @article {Gaignard2019, title = {Screening of marine microalgae: Investigation of new exopolysaccharide producers}, journal = {Algal Research}, volume = {44}, year = {2019}, note = {tex.ids= Gaignard2019a tex.mendeley-tags: RCC1084,RCC1196,RCC1504,RCC1714,RCC1774,RCC1786,RCC1863,RCC1978,RCC1983,RCC2035,RCC232,RCC2350,RCC2352,RCC2368,RCC2380,RCC2381,RCC2383,RCC2436,RCC2558,RCC2598,RCC2608,RCC2614,RCC2624,RCC2638,RCC269,RCC2696,RCC2703,RCC2932,RCC3069,RCC3072,RCC3092,RCC3093,RCC3436,RCC3649,RCC377,RCC4094,RCC4438,RCC4555,RCC4621,RCC4631,RCC4657,RCC76,RCC775,RCC821,RCC97 publisher: Elsevier}, month = {dec}, pages = {101711}, abstract = {Biopolymers, such as exopolysaccharides are widely exploited by industry as hydrocolloids (gelling, thickening agents) and biological agents (anti-inflammatory, anti-parasitic, antioxidant, etc.). In this study, 166 marine microalgae and cyanobacteria species have been screened in order to identify strains producing original exopolysaccharides. This screening allowed the highlighting of 45 positive strains. In a second time, the monosaccharide compositions from 20 EPS of them were determined by GC/MS and HPAEC-PAD. The results led to a discovery of 8 new genera of microalgae producing EPS, including polymers with a very original composition like richness in GlcA. Finally, a phylogenic tree has been contructed in order to assess the link between the phylogeny of microalgae and the global composition of their exopolymers, based on data obtained in this study and from the literature.}, keywords = {rcc1084, RCC1196, RCC1504, RCC1714, RCC1774, RCC1786, RCC1863, RCC1978, RCC1983, RCC2035, RCC232, RCC2350, RCC2352, RCC2368, rcc2380, RCC2381, RCC2383, RCC2436, RCC2558, RCC2598, RCC2608, RCC2614, RCC2624, RCC2638, RCC269, RCC2696, RCC2703, RCC2932, RCC3069, RCC3072, RCC3092, RCC3093, RCC3436, RCC3649, RCC377, RCC4094, RCC4438, RCC4555, RCC4621, RCC4631, RCC4657, RCC76, RCC775, RCC821, RCC97}, issn = {22119264}, doi = {10.1016/j.algal.2019.101711}, url = {https://www.sciencedirect.com/science/article/pii/S2211926419303261 https://linkinghub.elsevier.com/retrieve/pii/S2211926419303261}, author = {Gaignard, C. and Laroche, C. and Pierre, G. and Dubessay, P. and Delattre, C. and Gardarin, C. and Gourvil, P. and Probert, I. and Dubuffet, A. and Michaud, P.} } @article {Tsuboi2019, title = {Short-term changes in marine prokaryotic and eukaryotic microalgal communities exposed to the leachate of a seafloor hydrothermal sulfide}, journal = {Water, Air, \& Soil Pollution}, volume = {230}, year = {2019}, note = {tex.mendeley-tags: RCC,RCC1089,RCC262}, pages = {175}, abstract = {The effects of increased mining of seafloor massive sulfide deposits on marine ecosystems have not been characterized. In this study, the impact of leaching metals from a hydrothermal sulfide on photosynthetic protist and cyanobacterial communities in marine environments was investigated by amplicon analyses of small subunit rDNA (SSU rDNA) and rRNA (SSU rRNA). Seawater samples collected from the Iheya North region and Suruga Bay, Japan, were incubated with or without a leachate containing zinc, copper, cadmium, and manganese, of the actual seafloor hydrothermal sulfide from the Hakurei site in the Izena Hole region. The relative abundances of prasinophytes, diatom protists, and the cyanobacteria Synechococcus decreased substantially during incubation with leachate, indicating the vulnerability of these lineages to the leachate. Phylogenetic analysis based on the cyanobacterial phycocyanin cpcBA/rpcBA operon obtained from samples incubated with or without leachate indicated that the individual lineages of Synechococcus can determine sensitivity to heavy metals in different marine regions as well as particular clades and ecotypes.}, keywords = {rcc, RCC1089, RCC262}, doi = {10.1007/s11270-019-4224-8}, author = {Tsuboi, Shun and Yamaguchi, Haruyo and Fuchida, Shigeshi and Koshikawa, Hiroshi and Kawachi, Masanobu} } @article {Sanchez2019, title = {Simplified transformation of ostreococcus tauri using polyethylene glycol}, journal = {Genes}, volume = {10}, number = {5}, year = {2019}, note = {tex.mendeley-tags: RCC4221}, month = {may}, pages = {399}, abstract = {Ostreococcustauri is an easily cultured representative of unicellular algae (class Mamiellophyceae) that abound in oceans worldwide. Eight complete 13{\textendash}22 Mb genomes of phylogenetically divergent species within this class are available, and their DNA sequences are nearly always present in metagenomic data produced from marine samples. Here we describe a simplified and robust transformation protocol for the smallest of these algae (O. tauri). Polyethylene glycol (PEG) treatment was much more efficient than the previously described electroporation protocol. Short (2 min or less) incubation times in PEG gave {\textquestiondown}104 transformants per microgram DNA. The time of cell recovery after transformation could be reduced to a few hours, permitting the experiment to be done in a day rather than overnight as used in previous protocols. DNA was randomly inserted in the O. tauri genome. In our hands PEG was 20{\textendash}40-fold more efficient than electroporation for the transformation of O. tauri, and this improvement will facilitate mutagenesis of all of the dispensable genes present in the tiny O. tauri genome.}, keywords = {bioluminescence, Chlorophyta, Ecosystem, Gene Expression, luciferase, mamiellophyceae, Ostreococcus, picoeukaryote, plankton, Prasinophyte, promoter, RCC4221}, issn = {2073-4425}, doi = {10.3390/genes10050399}, url = {https://www.mdpi.com/2073-4425/10/5/399}, author = {Sanchez, Fr{\'e}d{\'e}ric and Geffroy, Sol{\`e}ne and Norest, Manon and Yau, Sheree and Moreau, Herv{\'e} and Grimsley, Nigel} } @article {Wilson2019, title = {Susceptibility of algae to Cr toxicity reveals contrasting metal management strategies}, journal = {Limnology and Oceanography}, volume = {64}, number = {5}, year = {2019}, note = {Publisher: John Wiley \& Sons, Ltd tex.mendeley-tags: RCC1,RCC1242,RCC4221,RCC950}, month = {sep}, pages = {2271{\textendash}2282}, abstract = {At the Paleozoic{\textendash}Mesozoic boundary, the dominance of marine eukaryotic algae shifted from the green (chlorophyll b) to the red (chlorophyll c) superfamily. Selection pressures caused by the bioavailability of trace metals associated with increasing oxygenation of the ocean may have played a key role in this algal revolution. From a scan of elemental compositions, a significant difference in the cellular Cr/P quota was found between the two superfamilies. Here, the different responses to high levels of Cr exposure reveal contrasting strategies for metal uptake and homeostasis in these algal lineages. At high Cr(VI) concentrations, red lineages experience growth inhibition through reduced photosynthetic capability, while green lineages are completely unaffected. Moreover, Cr(VI) has a more significant impact on the metallomes of red lineage algae, in which metal/P ratios increased with increasing Cr(VI) concentration for many trace elements. Green algae have higher specificity transporters to prevent Cr(VI) from entering the cell, and more specific intracellular stores of Cr within the membrane fraction than the red algae, which accumulate more Cr mistakenly in the cytosol fraction via lower affinity transport mechanisms. Green algal approaches require greater nutrient investments in the more numerous transport proteins required and management of specific metals, a strategy better adapted to the resource-rich coastal waters. By contrast, the red algae are nutrient-efficient with fewer and less discriminate metal transporters, which can be fast and better adapted in the oligotrophic, oxygenated open ocean, which has prevailed since the deepening of the oxygen minimum zones at the start of the Mesozoic era.}, keywords = {RCC1, RCC1242, RCC4221, RCC950}, issn = {0024-3590}, doi = {10.1002/lno.11183}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/lno.11183}, author = {Wilson, Will and Zhang, Qiong and Rickaby, Rosalind E. M.} } @article {Muller2018, title = {Stable isotope fractionation of strontium in coccolithophore calcite: Influence of temperature and carbonate chemistry}, journal = {Geobiology}, volume = {16}, number = {3}, year = {2018}, note = {Publisher: John Wiley \& Sons, Ltd (10.1111) tex.mendeley-tags: RCC1200}, month = {may}, pages = {297{\textendash}306}, abstract = {Abstract Marine calcifying eukaryotic phytoplankton (coccolithophores) is a major contributor to the pelagic production of CaCO3 and plays an important role in the biogeochemical cycles of C, Ca and other divalent cations present in the crystal structure of calcite. The geochemical signature of coccolithophore calcite is used as palaeoproxy to reconstruct past environmental conditions and to understand the underlying physiological mechanisms (vital effects) and precipitation kinetics. Here, we present the stable Sr isotope fractionation between seawater and calcite (?88/86Sr) of laboratory cultured coccolithophores in individual dependence of temperature and seawater carbonate chemistry. Coccolithophores were cultured within a temperature and a pCO2 range from 10 to 25{\textdegree}C and from 175 to 1,240 ?atm, respectively. Both environmental drivers induced a significant linear increase in coccolith stable Sr isotope fractionation. The temperature correlation at constant pCO2 for Emiliania huxleyi and Coccolithus braarudii is expressed as ?88/86Sr = ?7.611 ? 10?3 T + 0.0061. The relation of ?88/86Sr to pCO2 was tested in Emiliania huxleyi at 10 and 20{\textdegree}C and resulted in ?88/86Sr = ?5.394 ? 10?5 pCO2 ? 0.0920 and ?88/86Sr = ?5.742 ? 10?5 pCO2 ? 0.1351, respectively. No consistent relationship was found between coccolith ?88/86Sr and cellular physiology impeding a direct application of fossil coccolith ?88/86Sr as coccolithophore productivity proxy. An overall significant correlation was detected between the elemental distribution coefficient (DSr) and ?88/86Sr similar to inorganic calcite with a physiologically induced offset. Our observations indicate (i) that temperature and pCO2 induce specific effects on coccolith ?88/86Sr values and (ii) that strontium elemental ratios and stable isotope fractionation are mainly controlled by precipitation kinetics when embedded into the crystal lattice and subject to vital effects during the transmembrane transport from seawater to the site of calcification. These results provide an important step to develop a coccolith ?88/86Sr palaeoproxy complementing the existing toolbox of palaeoceanography.}, keywords = {coccolithophores, paleoproxy calibration, phytoplankton, RCC1200, stable Sr isotope fractionation}, issn = {1472-4677}, doi = {10.1111/gbi.12276}, url = {https://doi.org/10.1111/gbi.12276}, author = {M{\"u}ller, M N and Krabbenh{\"o}ft, A and Vollstaedt, H and Brandini, F P and Eisenhauer, A} } @article {Riou2017, title = {Specificity re-evaluation of oligonucleotide probes for the detection of marine picoplankton by tyramide signal amplification-fluorescent in situ hybridization}, journal = {Frontiers in Microbiology}, volume = {8}, number = {May}, year = {2017}, note = {tex.mendeley-tags: RCC257}, month = {may}, pages = {854}, abstract = {Oligonucleotide probes are increasingly being used to characterize natural microbial assemblages by Tyramide Signal Amplification-Fluorescent in situ Hybridization (TSA-FISH, or CAtalysed Reporter Deposition CARD-FISH). In view of the fast-growing rRNA databases, we re-evaluated the in silico specificity of eleven bacterial and eukaryotic probes and competitor frequently used for the quantification of marine picoplankton. We performed tests on cell cultures to decrease the risk for non-specific hybridization, before they are used on environmental samples. The probes were confronted to recent databases and hybridization conditions were tested against target strains matching perfectly with the probes, and against the closest non-target strains presenting one to four mismatches. We increased the hybridization stringency from 55\% to 65\% formamide for the Eub338+EubII+EubIII probe mix to be specific to the Eubacteria domain. In addition, we found that recent changes in the Gammaproteobacteria classification decreased the specificity of Gam42a probe, and that the Roseo536R and Ros537 probes were not specific to, and missed part of the Roseobacter clade. Changes in stringency conditions were important for bacterial probes; these induced respectively a significant increase, in Eubacteria and Roseobacter and no significant changes in Gammaproteobacteria concentrations from the investigated natural environment. We confirmed the eukaryotic probes original conditions, and propose the Euk1209+NChlo01+Chlo02 probe mix to target the largest picoeukaryotic diversity. Experiences acquired through these investigations leads us to propose the use of seven steps protocol for complete FISH probe specificity check-up to improve data quality in environmental studies.}, keywords = {CARD-FISH, Eukaryota, oligonucleotide, PROBES, Prokaryote, RCC257, specificity, TSA-FISH}, issn = {1664-302X}, doi = {10.3389/fmicb.2017.00854}, url = {http://journal.frontiersin.org/article/10.3389/fmicb.2017.00854/full}, author = {Riou, Virginie and P{\'e}riot, Marine and Biegala, Isabelle C.} } @article {Vannier2016, title = {Survey of the green picoalga Bathycoccus genomes in the global ocean}, journal = {Scientific Reports}, volume = {6}, number = {1}, year = {2016}, note = {tex.mendeley-tags: 2016,RCC1105,RCC715,RCC716,sbr?hyto$_\textrmd$ipo,sbr?hyto?ppo}, month = {dec}, pages = {37900}, keywords = {2016, RCC1105, RCC715, RCC716, sbr?hyto$_\textrmd$ipo, sbr?hyto?ppo}, issn = {2045-2322}, doi = {10.1038/srep37900}, url = {http://www.nature.com/articles/srep37900}, author = {Vannier, Thomas and Leconte, Jade and Seeleuthner, Yoann and Mondy, Samuel and Pelletier, Eric and Aury, Jean-Marc and de Vargas, Colomban and Sieracki, Michael and Iudicone, Daniele and Vaulot, Daniel and Wincker, Patrick and Jaillon, Olivier} } @article {Kashtan2014, title = {Single-cell genomics reveals hundreds of coexisting subpopulations in wild prochlorococcus}, journal = {Science}, volume = {344}, number = {6182}, year = {2014}, note = {tex.mendeley-tags: RCC278}, pages = {416{\textendash}420}, abstract = {Extensive genomic diversity within coexisting members of a microbial species has been revealed through selected cultured isolates and metagenomic assemblies. Yet, the cell-by-cell genomic composition of wild uncultured populations of co-occurring cells is largely unknown. In this work, we applied large-scale single-cell genomics to study populations of the globally abundant marine cyanobacterium Prochlorococcus. We show that they are composed of hundreds of subpopulations with distinct {\textquotedblleft}genomic backbones,{\textquotedblright} each backbone consisting of a different set of core gene alleles linked to a small distinctive set of flexible genes. These subpopulations are estimated to have diverged at least a few million years ago, suggesting ancient, stable niche partitioning. Such a large set of coexisting subpopulations may be a general feature of free-living bacterial species with huge populations in highly mixed habitats.}, keywords = {RCC278}, doi = {10.1126/science.1248575}, url = {http://www.sciencemag.org/content/344/6182/416.abstract}, author = {Kashtan, Nadav and Roggensack, Sara E and Rodrigue, S{\'e}bastien and Thompson, Jessie W and Biller, Steven J and Coe, Allison and Ding, Huiming and Marttinen, Pekka and Malmstrom, Rex R and Stocker, Roman and Follows, Michael J and Stepanauskas, Ramunas and Chisholm, Sallie W} } @article {Dia2014, title = {Spatiotemporal changes in the genetic diversity of harmful algal blooms caused by the toxic dinoflagellate Alexandrium minutum}, journal = {Molecular Ecology}, volume = {23}, number = {3}, year = {2014}, note = {tex.mendeley-tags: 2014,macumba,rcc,sbr?hyto$_\textrmd$ipo}, pages = {549{\textendash}560}, abstract = {Organisms with sexual and asexual reproductive systems benefit from both types of reproduction. Sexual recombination generates new combinations of alleles, whereas clonality favours the spread of the fittest genotype through the entire population. Therefore, the rate of sexual vs. clonal reproduction has a major influence on the demography and genetic structure of natural populations. We addressed the effect of reproductive system on populations of the dinoflagellate Alexandrium minutum. More specifically, we monitored the spatiotemporal genetic diversity during and between bloom events in two estuaries separated by 150 km for two consecutive years. An analysis of population genetic patterns using microsatellite markers revealed surprisingly high genotypic and genetic diversity. Moreover, there was significant spatial and temporal genetic differentiation during and between bloom events. Our results demonstrate that (i) interannual genetic differentiation can be very high, (ii) estuaries are partially isolated during bloom events and (iii) genetic diversity can change rapidly during a bloom event. This rapid genetic change may reflect selective effects that are nevertheless not strong enough to reduce allelic diversity. Thus, sexual reproduction and/or migration may regularly erase any genetic structure produced within estuaries during a bloom event.}, keywords = {2014, bloom dynamics, clonality, linkage disequilibrium, MACUMBA, population genetics, rcc, RCC?o?dd, resting cyst, SBR$_\textrmP$hyto$_\textrmD$PO, sbr?hyto$_\textrmd$ipo, sexual reproduction}, doi = {10.1111/mec.12617}, url = {http://dx.doi.org/10.1111/mec.12617}, author = {Dia, A and Guillou, L and Mauger, S and Bigeard, E and Marie, D and Valero, M and Destombe, C} } @article {Baines2012, title = {Significant silicon accumulation by marine picocyanobacteria}, journal = {Nature Geoscience}, volume = {5}, number = {12}, year = {2012}, note = {arXiv: 9605103 [cs] ISBN: 1752-08941?752-0908 Publisher: Nature Publishing Group tex.arxivid: cs/9605103 tex.mendeley-tags: rcc1084,rcc1086,rcc752}, pages = {886{\textendash}891}, abstract = {The marine silicon cycle is thought to be intimately tied to the carbon cycle through its effect on the growth of diatoms. These unicellular algae form substantial blooms in cold, nutrient-rich waters. Their dense, siliceous cell walls promote the sinking of particulate matter, and all the carbon and nutrients contained therein1. As such, diatoms are thought to be the primary organisms responsible for the low levels of dissolved silicon observed in the surface ocean and the export of mineral silica to depth. Here, we use synchrotron X-ray fluorescence microscopy to determine the elemental composition of individual diatoms and cyanobacterial cells from the eastern equatorial Pacific and the Sargasso Sea.We show that cells of Synechococcus, a small unicellular marine cyanobacterium that dominates in nutrient-depleted waters2, can exhibit cellular ratios of silicon to sulphur, and silicon to phosphorus, approaching those detected in diatoms in the same location. Silicon accumulation was also observed in cultured Synechococcus strains. We estimate that the water column inventory of silicon in Synechococcus can exceed that of diatomsinsomecases.We suggest that picocyanobacteriamay exert a previously unrecognized influence on the oceanic silicon cycle, especially in nutrient-poorwaters.}, keywords = {rcc1084, RCC1086, rcc752}, issn = {1752-0894}, doi = {10.1038/ngeo1641}, url = {http://www.nature.com/doifinder/10.1038/ngeo1641}, author = {Baines, Stephen B. and Twining, Benjamin S. and Brzezinski, Mark a. and Krause, Jeffrey W. and Vogt, Stefan and Assael, Dylan and McDaniel, Hannah} } @article {Beaufort2011, title = {Sensitivity of coccolithophores to carbonate chemistry and ocean acidification}, journal = {Nature}, volume = {476}, year = {2011}, note = {tex.mendeley-tags: 2011,rcc,sbr?hyto?ppo}, pages = {80{\textendash}83}, abstract = {Coccolithophores produce the major fraction of pelagic carbonate, a key component of the carbon cycle. The effect of elevated CO2 on their calcification is poorly understood. Culture experiments have yielded varied calcification responses to increased pCO2 between and within coccolithophore taxa. We used a novel automated method for pattern recognition and morphometric analysis to quantify the calcite mass of coccolithophores from {\textquestiondown}700 samples from present past (last 40-Kyr) oceans. Comparison of morphological data with ocean carbonate chemistry reconstructed in both space and time indicate decreasing calcification with increasing pCO2, and decreasing CO32. At pH {\textexclamdown}8.0, delicate Emiliania huxleyi are strongly affected by decalcification. However, highly calcified E. huxleyi morphotypes predominate in waters with lowest pH. This suggests that coccolithophore strains pre-adapted to future, more acidic oceans already populate regions of contemporary oceans. The future carbon feedback from coccolithophore calcification will depend on the genetic diversity and adaptability of coccolithophore populations.}, keywords = {2011, rcc, SBR$_\textrmP$hyto$_\textrmE$PPO, sbr?hyto?ppo}, doi = {10.1038/nature10295}, author = {Beaufort, L and Probert, I and de Garidel-Thoron, T and Bendif, E M and Ruiz-Pino, D and Metzl, N and Goyet, C and Buchet, N and Coupel, P and Grelaud, M and Rost, B and Rickaby, R E M and de Vargas, C} } @article {Jardillier2010, title = {Significant CO2 fixation by small prymnesiophytes in the subtropical and tropical northeast Atlantic Ocean}, journal = {The ISME Journal}, volume = {4}, year = {2010}, note = {Publisher: International Society for Microbial Ecology tex.mendeley-tags: Micromonas,rcc}, pages = {1180{\textendash}1192}, keywords = {Micromonas, rcc}, doi = {10.1038/ismej.2010.36}, url = {http://dx.doi.org/10.1038/ismej.2010.36 http://www.nature.com/ismej/journal/vaop/ncurrent/suppinfo/ismej201036s1.html}, author = {Jardillier, Ludwig and Zubkov, Mikhail V and Pearman, John and Scanlan, David J} } @article {Langer2009, title = {Strain-specific responses of Emiliania huxleyi to changing seawater carbonate chemistry}, journal = {Biogeosciences}, volume = {6}, number = {11}, year = {2009}, note = {ISBN: 1726-4170 tex.mendeley-tags: 2009,rcc}, pages = {2637{\textendash}2646}, abstract = {Four strains of the coccolithophore E. huxleyi (RCC1212, RCC1216, RCC1238, RCC1256) were grown in dilute batch culture at four CO2 levels ranging from similar to 200 mu atm to similar to 1200 mu atm. Growth rate, particulate organic carbon content, and particulate inorganic carbon content were measured, and organic and inorganic carbon production calculated. The four strains did not show a uniform response to carbonate chemistry changes in any of the analysed parameters and none of the four strains displayed a response pattern previously described for this species. We conclude that the sensitivity of different strains of E. huxleyi to acidification differs substantially and that this likely has a genetic basis. We propose that this can explain apparently contradictory results reported in the literature.}, keywords = {2009, rcc, SBR$_\textrmP$hyto$_\textrmE$PPO}, doi = {10.5194/bg-6-2637-2009}, author = {Langer, G and Nehrke, G and Probert, I and Ly, J and Ziveri, P} } @article {Piganeau2007, title = {Screening the Sargasso Sea metagenome for data to investigate genome evolution in Ostreococcus (Prasinophyceae, Chlorophyta)}, journal = {Gene}, volume = {406}, year = {2007}, note = {tex.mendeley-tags: RCC,rcc}, pages = {184{\textendash}190}, abstract = {The Sargasso Sea water shotgun sequencing unveiled an unprecedented glimpse of marine prokaryotic diversity and gene content. The sequence data was gathered from 0.8 ??m filtered surface water extracts, and revealed picoeukaryotic (cell size {\textexclamdown} 2 ??m) sequences alongside the prokaryotic data. We used the available genome sequence of the picoeukaryote Ostreococcus tauri (Prasinophyceae, Chlorophyta) as a benchmark for the eukaryotic sequence content of the Sargasso Sea metagenome. Sequence data from at least two new Ostreococcus strains were identified and analyzed, and showed a bias towards higher coverage of the AT-rich organellar genomes. The Ostreococcus nuclear sequence data retrieved from the Sargasso metagenome is divided onto 731 scaffolds of average size 3917 bp, and covers 23\% of the complete nuclear genome and 14\% of the total number of protein coding genes in O. tauri. We used this environmental Ostreococcus sequence data to estimate the level of constraint on intronic and intergenic sequences in this compact genome.}, keywords = {rcc}, doi = {10.1016/j.gene.2007.09.015}, author = {Piganeau, G and Moreau, H} } @article {Sandaa2006, title = {Seasonal variations in virus-host populations in norwegian coastal waters: Focusing on the cyanophage community infecting marine synechococcus spp.}, journal = {Applied and Environmental Microbiology}, volume = {72}, number = {7}, year = {2006}, note = {ISBN: 0099-2240 tex.mendeley-tags: RCC2035}, month = {jul}, pages = {4610{\textendash}4618}, abstract = {Viruses are ubiquitous components of the marine ecosystem. In the current study we investigated seasonal variations in the viral community in Norwegian coastal waters by pulsed-field gel electrophoresis (PFGE). The results demonstrated that the viral community was diverse, displaying dynamic seasonal variation, and that viral populations of 29 different sizes in the range from 26 to 500 kb were present. Virus populations from 260 to 500 kb and dominating autotrophic pico- and nanoeukaryotes showed similar dynamic variations. Using flow cytometry and real-time PCR, we focused in particular on one host-virus system: Synechococcus spp. and cyanophages. The two groups covaried throughout the year and were found in the highest amounts in fall with concentrations of 7.3 x 10(4) Synechococcus cells ml(-1) and 7.2 x 10(3) cyanophage ml(-1). By using primers targeting the g20 gene in PCRs on DNA extracted from PFGE bands, we demonstrated that cyanophages were found in a genomic size range of 26 to 380 kb. The genetic richness of the cyanophage community, determined by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified g20 gene fragments, revealed seasonal shifts in the populations, with one community dominating in spring and summer and a different one dominating in fall. Phylogenetic analysis of the sequences originating from PFGE and DGGE bands grouped the sequences into three groups, all with homology to cyanomyoviruses present in cultures. Our results show that the cyanophage community in Norwegian coastal waters is dynamic and genetically diverse and has a surprisingly wide genomic size range.}, keywords = {RCC2035}, issn = {0099-2240}, doi = {10.1128/AEM.00168-06}, url = {http://aem.asm.org/cgi/doi/10.1128/AEM.00168-06}, author = {Sandaa, R.-A. and Larsen, Aud} } @article {Ral2004, title = {Starch division and partitioning. A mechanism for granule propagation and maintenance in the picophytoplanktonic green alga Ostreococcus tauri}, journal = {Plant Physiology}, volume = {136}, number = {2}, year = {2004}, note = {tex.mendeley-tags: RCC745}, pages = {3333{\textendash}3340}, abstract = {Whereas Glc is stored in small-sized hydrosoluble glycogen particles in archaea, eubacteria, fungi, and animal cells, photosynthetic eukaryotes have resorted to building starch, which is composed of several distinct polysaccharide fractions packed into a highly organized semicrystalline granule. In plants, both the initiation of polysaccharide synthesis and the nucleation mechanism leading to formation of new starch granules are currently not understood. Ostreococcus tauri, a unicellular green alga of the Prasinophyceae family, defines the tiniest eukaryote with one of the smallest genomes. We show that it accumulates a single starch granule at the chloroplast center by using the same pathway as higher plants. At the time of plastid division, we observe elongation of the starch and division into two daughter structures that are partitioned in each newly formed chloroplast. These observations suggest that in this system the information required to initiate crystalline polysaccharide growth of a new granule is contained within the preexisting polysaccharide structure and the design of the plastid division machinery.}, keywords = {Adp Glucose Pyrophosphorylase, Amylopectin, Arabidopsis, Bacterial Glycogen, Biogenesis, Biosynthesis, Chlamydomonas Reinhardtii, Enzyme, Prasinophyceae, rcc, RCC745, Synthase}, doi = {10.1104/pp.104.044131}, author = {Ral, J P and Derelle, E and Ferraz, C and Wattebled, F and Farinas, B and Corellou, F and Buleon, A and Slomianny, M C and Delvalle, D and D, Hulst C and Rombauts, S and Moreau, H and Ball, S} } @article {Toledo2003, title = {A Synechococcus serotype is found preferentially in surface marine waters}, journal = {Limnology and Oceanography}, volume = {48}, number = {5}, year = {2003}, note = {tex.mendeley-tags: RCC,rcc}, pages = {1744{\textendash}1755}, abstract = {In marine ecosystems, gradients of light, temperature, and nutrients occur horizontally (coastal to offshore) and vertically. The extent to which microorganisms acclimate or speciate in response to these gradients is under active investigation. Strain isolation data (e.g., site or depth), environmental DNA clone libraries, and preliminary physiology experiments have indicated that marine Synechococcus strain CC9605 might be adapted to the surface oligotrophic ocean. In the present work, we used an immunofluorescent approach to detect the CC9605 serotype in the California Current during September 1998. At two offshore stations, samples were collected along vertical profiles. The relative abundance of the CC9605 serotype was significantly higher in shallow depths within the mixed layer than in deeper depths at the two stations, with maximum values (+/- standard deviation) of 10.3\% +/- 6.4 and 28.7\% +/- 9.5. Surface samples along an offshore-inshore transect showed higher abundance in the most oligotrophic site (8\% +/- 3), compared with almost 1\% inshore, but one coastal site also had high relative abundance of the CC9605 serotype (7\% +/- 0.5). These data indicate that Synechococcus strains are not uniformly distributed and that some strains, such as CC9605, are more abundant in the mixed layer of the euphotic zone than below the mixed layer.}, keywords = {Aquatic-sciences, california-current, cyanobacteria-, diversity-, flow-cytometry, immunofluorescence-, North-atlantic-ocean, phytoplankton-, prochlorococcus-populations, rcc, sargasso-sea, strains-}, doi = {10.4319/lo.2003.48.5.1744}, author = {Toledo, G and Palenik, B} } @article {Guillou1999b, title = {Symbiomonas scintillans gen. et sp nov and Picophagus flagellatus gen. et sp nov (Heterokonta): Two new heterotrophic flagellates of picoplanktonic size}, journal = {Protist}, volume = {150}, number = {4}, year = {1999}, note = {ISBN: 1434-4610 Publisher: Urban \& Fischer Verlag tex.address: Branch Office Jena, P O Box No.100 537, D-07705 Jena, Germany tex.mendeley-tags: 1999,rcc,sbr?hyto}, pages = {383{\textendash}398}, abstract = {Two new oceanic free-living heterotrophic Heterokonta species with picoplanktonic size ({\textexclamdown} 2 mu m) are described, Symbiomonas scintillans Guillou et Chretiennot-Dinet gen. Ef sp. Nov, was isolated from samples collected both in the equatorial Pacific Ocean and the Mediterranean Sea. This new species possesses ultrastructural features of the bicosoecids, such as the absence of a helix in the flagellar transitional region (found in Cafeteria roenbergensis and in a few bicosoecids), and a flagellar root system very similar to that of C. Roenbergensis, Acronema sippewissettensis, and Bicosoeca maris. This new species is characterized by a single flagellum with mastigonemes, the presence of endosymbiotic bacteria located close to the nucleus, the absence of a lorica and a R3 root composed of a 6+3+x microtubular structure. Phylogenetical analyses of nuclear-encoded SSU rDNA gene sequences indicate that this species is close to the bicosoecids C. Roenbergensis and Siluania monomastiga. Picophagus flagellatus Guillou et Chretiennot-Dinet gen. Et sp. Nov. Was collected in the equatorial Pacific Ocean, Cells are naked and possess two flagella, This species is characterized by the lack of a transitional helix and lateral filaments on the flagellar tubular hairs, the absence of siliceous scales, two unequal flagella, R1 + R3 roots, and the absence of a rhizoplast. SSU rDNA analyses place this strain at the base of the Chrysophyceae/Synurophyceae lineages.}, keywords = {1999, APPARATUS, DEVELOPAYELLA-ELEGANS, EMPHASIS, MOLECULAR PHYLOGENY, picophytoplankton, PLASTIDS, rcc, RDNA, SBR$_\textrmP$hyto, sbr?hyto, SEQUENCES}, doi = {10.1016/S1434-4610(99)70040-4}, author = {Guillou, L and Chr{\'e}tiennot-Dinet, M.-J. and Boulben, S and Moon-van der Staay, S Y and Vaulot, D} } @article {toledo_synechococcus_1997, title = {Synechococcus diversity in the California current as seen by RNA polymerase (rpoC1) gene sequences of isolated strains.}, journal = {Applied and environmental microbiology}, volume = {63}, number = {11}, year = {1997}, pages = {4298{\textendash}4303}, keywords = {RCC1086}, issn = {0099-2240}, doi = {10.1128/AEM.63.11.4298-4303.1997}, url = {https://AEM.asm.org/content/63/11/4298}, author = {Toledo, G and Palenik, B} } @article {Raghu-Kumar1988, title = {Schizochytrium mangrovei sp. nov., a thraustochytrid from mangroves in India}, journal = {Transactions of the British Mycological Society}, volume = {90}, number = {4}, year = {1988}, note = {ISBN: 0007-1536 Publisher: British Mycological Society tex.mendeley-tags: RCC893}, month = {jun}, pages = {627{\textendash}631}, abstract = {Schizochytrium mangrovei sp. nov. on decaying mangrove leaves is described from Goa, India. In sea water/pine pollen cultures, the encysted zoospore divides by repeated binary divisions to form 4, 6, 8 or 12 cells. Instead of forming sporangia as in the other species of Schizochytrium, these cells directly become zoospores. In nutrient liquid media, the developmental stages resemble those of Ulkenia. A key to the species of Schizochytrium is given.}, keywords = {RCC893}, issn = {00071536}, doi = {10.1016/S0007-1536(88)80068-8}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0007153688800688}, author = {Raghu-Kumar, S.} }