@article {veron_new_2023, title = {New species of Pavlovophyceae (Haptophyta) and revision of the genera Exanthemachrysis, Rebecca and Pavlova}, journal = {European Journal of Taxonomy}, volume = {861}, year = {2023}, month = {mar}, pages = {21{\textendash}47}, abstract = {The justification of the 4 genera that currently compose the class Pavlovophyceae is based on a low number of species and a relative paucity of available, traceable and referenced cultures. Previous integrative phylogeny work revealed strains that can refine and strengthen our knowledge of the genera in the class. The application of multiple light and electron microscopy techniques allowed us to prioritize the cytomorphological characters (pyrenoid, thylakoid, stigma, knob-scales, life stage / life cycle) used for the taxonomy of these algae and to describe two new species: Exanthemachrysis fresneliae V{\'e}ron sp.~nov. and Rebecca billardiae V{\'e}ron sp.~nov. Consequently, revisions of the two genera Exanthemachrysis Lepailleur emend. V{\'e}ron and Rebecca Green emend. V{\'e}ron were made. In addition, the genus Pavlova Butcher emend V{\'e}ron is revised in the light of these characters. Particular emphasis is placed on the life stages and habitat of the species.}, keywords = {habitats, haptophytes, new species, phytoplankton, pyrenoid, RCC1528, RCC1541}, issn = {2118-9773}, doi = {10.5852/ejt.2023.861.2063}, url = {https://europeanjournaloftaxonomy.eu/index.php/ejt/article/view/2063}, author = {Veron, Benoit and Rougier, Etienne and Taylor, Anthony and Goux, Didier} } @booklet {wang_novel_2023, title = {Novel dimethylsulfoniopropionate biosynthesis enzymes in diverse marine bacteria, cyanobacteria and abundant algae}, year = {2023}, month = {mar}, publisher = {In Review}, type = {preprint}, abstract = {Abstract Dimethylsulfoniopropionate (DMSP) is an abundant marine organosulfur compound[1] with roles in stress protection[2, 3], chemotaxis[4], nutrient and sulfur cycling[5] and, potentially, climate regulation[6, 7]. Marine algae and bacteria are considered significant DMSP producers, but many diverse representatives lack known DMSP synthesis genes/enzymes[8, 9]. Here, new DMSP biosynthesis enzymes were identified that considerably increase the number and diversity of potential DMSP-producing organisms, inferring new and significant global DMSP producers. A novel bifunctional DMSP biosynthesis enzyme, DsyGD, identified in the rhizobacterium Gynuella sunshinyii, produces DMSP at levels higher than any other bacterium from methylthiohydroxybutyrate (MTHB) via an N-terminal MTHB S-methyltransferase domain (termed DsyG) and a C-terminal dimethylsulfoniohydroxybutyrate (DMSHB) decarboxylase domain (termed DsyD, which is the first reported enzyme with this activity). DsyGD is also found in some filamentous cyanobacteria, not previously known to produce DMSP. Regulation of DMSP production and dsyGD transcription was consistent with their role in osmoprotection. Indeed, cloned dsyGD conferred osmotolerance to bacteria deficient in osmolyte production, something not previously demonstrated for any known DMSP synthesis gene, and which could be exploited for biotechnology e.g., engineering salt tolerance. DsyGD characterisation led to identification of phylogenetically distinct DsyG-like proteins, termed DSYE, with MTHB S-methyltransferase activity, in diverse and environmentally abundant Chlorophyta, Chlorachniophyta, Ochraphyta, Haptophyta and Bacillariophyta algae. These algae comprise a mix of low, high and previously unknown DMSP producers[10]. Algae containing DSYE, particularly bloom-forming Pelagophyceae species, which we showed to accumulate medium-high intracellular DMSP levels, were globally more abundant DMSP producers than Haptophyta, Dinophyta and Bacillariophyta with DSYB and/or TpMMT. This highlights the potential importance of Pelagophyceae and other DSYE containing algae in global DMSP production and sulfur cycling.}, keywords = {RCC100, RCC2956, RCC4094, RCC4422, RCC6172}, doi = {10.21203/rs.3.rs-2678769/v1}, url = {https://www.researchsquare.com/article/rs-2678769/v1}, author = {Wang, Jinyan and Zhou, Shun and Curson, Andrew and Vieira, Ana and Walsham, Keanu and Monaco, Serena and Li, Chun-Yang and Rivera, Peter Paolo and Wang, Xiao-Di and Hanwell, Libby and Zhu, Xiao-Yu and Le{\~a}o, Pedro and Lea-Smith, David J. and Zhang, Yuzhong and Zhang, Xiaohua and Todd, Jonathan} } @article {concordio-reis_novel_2023, title = {Novel exopolysaccharide produced by the marine dinoflagellate Heterocapsa AC210: Production, characterization, and biological properties}, journal = {Algal Research}, volume = {70}, year = {2023}, pages = {103014}, abstract = {Marine microalgae are promising sources of novel valuable biomolecules such as polysaccharides. In this study, the dinoflagellate Heterocapsa sp. AC210 was described as a new exopolysaccharide (EPS) producer. The cultivation and EPS production in bioreactor was evaluated for the first time in detail. The EPS was composed of seven different sugar monomers, including fucose and glucosamine, which are quite rare and have never been reported in dinoflagellates{\textquoteright} EPS. Moreover, the EPS had a high content of sulphate, which is often associated with biological properties. Cytotoxicity was accessed and the results showed that the EPS did not reduce cell viability for concentrations up to 1~g~L-1. Additionally, antioxidant and anti-inflammatory assays demonstrated that the EPS reduced by 18~\% the intracellular reactive oxygen species and decreased up to 79.3~\% and 46.2~\% of IL-8 and IL-6 secretion in keratinocytes, which supports its potential application in the cosmeceutical and biomedical fields.}, keywords = {Anti-inflammatory, Cytotoxicity, Dinoflagellates, Exopolysaccharide production, Marine microalgae, RCC1514, sp. AC210}, issn = {2211-9264}, doi = {10.1016/j.algal.2023.103014}, url = {https://www.sciencedirect.com/science/article/pii/S2211926423000474}, author = {Conc{\'o}rdio-Reis, Patr{\'\i}cia and Cardeira, Martim and Macedo, Ana Catarina and Ferreira, S{\'o}nia S. and Serra, Ana Teresa and Coimbra, Manuel A. and Amorim, Ana and Reis, Maria A. M. and Freitas, Filomena} } @booklet {barton_novel_2023, title = {A novel fluoro-electrochemical technique for classifying diverse marine nanophytoplankton}, year = {2023}, month = {apr}, publisher = {Life Sciences}, type = {preprint}, abstract = {

To broaden our understanding of pelagic ecosystem responses to environmental change, it is essential that we improve the spatio-temporal resolution of in situ monitoring of phytoplankton communities. A key challenge for existing methods is in classifying and quantifying cells within the nanophytoplankton size range (2-20{\textmu}m). This is particularly difficult when there are similarities in morphology, making visual differentiation difficult for both trained taxonomists and machine learning based approaches. Here we present a rapid fluoro-electrochemical technique for classifying nanophytoplankton, and using a library of 52 diverse strains of nanophytoplankton we assess the accuracy of this technique based on two measurements at the individual level: charge required to reduce per cell chlorophyll a fluorescence by 50\%, and cell radius. We demonstrate a high degree of accuracy overall (\>90\%) in categorising cells belonging to widely recognised key functional groups, however this is reduced when we consider the broader diversity of {\textquotedblleft}nano-phytoflagellates{\textquotedblright}. Notably, we observe that some groups, for example calcifying Isochrysidales, have much greater resilience to electrochemically driven oxidative conditions relative to others of a similar size, making them more easily categorised by the technique. The findings of this study present a promising step forward in advancing our toolkit for monitoring phytoplankton communities. We highlight that, for improved categorisation accuracy, future iterations of the method can be enhanced by measuring additional predictor variables with minimal adjustments to the set-up. In doing so, we foresee this technique being highly applicable, and potentially invaluable, for in situ classification and enumeration of the nanophytoplankton size fraction.

}, keywords = {RCC1, rcc1084, RCC1130, RCC1150, RCC1178, RCC1185, RCC1198, RCC1216, rcc1217, RCC1242, RCC1314, RCC1346, RCC1489, RCC1511, RCC1546, RCC1557, RCC1614, rcc1731, RCC191, RCC2570, RCC3598, RCC3696, RCC3776, RCC3780, RCC4207, RCC4221, RCC4273, RCC4657, RCC4660, RCC6, RCC623, RCC6516, RCC656, RCC678, RCC69, RCC74, RCC76, RCC8, RCC80, RCC81, RCC88, RCC911, RCC950}, doi = {10.1002/lom3.10572}, url = {https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lom3.10572}, author = {Barton, Samuel and Yang, Minjun and Chen, Haotian and Batchelor-McAuley, Christopher and Compton, Richard and Bouman, Heather and Rickaby, Rosalind} } @article {johnson_nutritional_2022, title = {Nutritional response of a coccolithophore to changing pH and temperature}, journal = {Limnology and Oceanography}, volume = {n/a}, number = {n/a}, year = {2022}, note = {_eprint: https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lno.12204}, abstract = {Coccolithophores are a calcifying unicellular phytoplankton group that are at the base of the marine food web, and their lipid content provides a source of energy to consumers. Coccolithophores are vulnerable to ocean acidification and warming, therefore it is critical to establish the effects of climate change on these significant marine primary producers, and determine potential consequences that these changes can have on their consumers. Here, we quantified the impact of changes in pH and temperature on the nutritional condition (lipid content, particulate organic carbon/nitrogen), growth rate, and morphology of the most abundant living coccolithophore species, Emiliania huxleyi. We used a regression type approach with nine pH levels (ranging from 7.66 to 8.44) and two temperatures (15{\textdegree}C and 20{\textdegree}C). Lipid production was greater under reduced pH, and growth rates were distinctly lower at 15{\textdegree}C than at 20{\textdegree}C. The production potential of lipids, which estimates the availability of lipids to consumers, increased under 20{\textdegree}C, but decreased under low pH. The results indicate that, while consumers will benefit energetically under ocean warming, this benefit will be mitigated by ocean acidification. The carbon to nitrogen ratio was higher at 20{\textdegree}C and low pH, indicating that the nutritional quality of coccolithophores for consumers will decline under climate change. The impact of low pH on the structural integrity of the coccosphere may also mean that coccolithophores are easier to digest for consumers. Many responses suggest cellular stress, indicating that increases in temperature and reductions in pH may have a negative impact on the ecophysiology of coccolithophores.}, keywords = {RCC1832}, issn = {1939-5590}, doi = {10.1002/lno.12204}, url = {http://onlinelibrary.wiley.com/doi/abs/10.1002/lno.12204}, author = {Johnson, Roberta and Langer, Gerald and Rossi, Sergio and Probert, Ian and Mammone, Marta and Ziveri, Patrizia} } @article {decamp_new_2021, title = {A New, Quick, and Simple Protocol to Evaluate Microalgae Polysaccharide Composition}, journal = {Marine Drugs}, volume = {19}, number = {2}, year = {2021}, pages = {101}, abstract = {In this work, a new methodological approach, relying on the high specificity of enzymes in a complex mixture, was developed to estimate the composition of bioactive polysaccharides produced by microalgae, directly in algal cultures. The objective was to set up a protocol to target oligomers commonly known to be associated with exopolysaccharides{\textquoteright} (EPS) nutraceutical and pharmaceutical activities (i.e., rhamnose, fucose, acidic sugars, etc.) without the constraints classically associated with chromatographic methods, while maintaining a resolution sufficiently high to enable their monitoring in the culture system. Determination of the monosaccharide content required the application of acid hydrolysis (2 M trifluoroacetic acid) followed by NaOH (2 M) neutralization. Quantification was then carried out directly on the fresh hydrolysate using enzyme kits corresponding to the main monosaccharides in a pre-determined composition of the polysaccharides under analysis. Initial results showed that the enzymes were not sensitive to the presence of TFA and NaOH, so the methodology could be carried out on fresh hydrolysate. The limits of quantification of the method were estimated as being in the order of the log of nanograms of monosaccharides per well, thus positioning it among the chromatographic methods in terms of analytical performance. A comparative analysis of the results obtained by the enzymatic method with a reference method (high-performance anion-exchange chromatography) confirmed good recovery rates, thus validating the closeness of the protocol. Finally, analyses of raw culture media were carried out and compared to the results obtained in miliQ water; no differences were observed. The new approach is a quick, functional analysis method allowing routine monitoring of the quality of bioactive polysaccharides in algal cultures grown in photobioreactors.}, keywords = {rcc2380, RCC3438}, issn = {1660-3397}, doi = {10.3390/md19020101}, url = {https://www.mdpi.com/1660-3397/19/2/101}, author = {Decamp, Antoine and Michelo, Orane and Rabbat, Christelle and Laroche, C{\'e}line and Grizeau, Dominique and Pruvost, J{\'e}r{\'e}my and Gon{\c c}alves, Olivier} } @article {jimenez_no_2021, title = {No evidence of Phago-mixotropy in Micromonas polaris (Mamiellophyceae), the Dominant Picophytoplankton Species in the Arctic}, journal = {Journal of Phycology}, volume = {57}, number = {2}, year = {2021}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jpy.13125}, pages = {435{\textendash}446}, abstract = {In the Arctic Ocean, the small green alga Micromonas polaris dominates picophytoplankton during the summer months but is also present in winter. It has been previously hypothesized to be phago-mixotrophic (capable of bacteria ingestion) based on laboratory and field experiments. Prey uptake was analyzed in several M. polaris strains isolated from different regions and depths of the Arctic Ocean and in Ochromonas triangulata, a known phago-mixotroph used as a control. Measuring ingestion of either fluorescent beads or fluorescently labeled bacteria by flow cytometry, we found no evidence of phago-mixotrophy in any M. polaris strain while O. triangulata was ingesting both beads and bacteria. In addition, in silico predictions revealed that members of the genus Micromonas lack a genetic signature of phagocytotic capacity.}, keywords = {Arctic, Micromonas, phago-mixotrophy, phytoplankton, rcc, RCC21, RCC2288, RCC2306, RCC4298}, issn = {1529-8817}, doi = {10.1111/jpy.13125}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jpy.13125}, author = {Jimenez, Valeria and Burns, John A. and Le Gall, Florence and Not, Fabrice and Vaulot, Daniel} } @article {harada_novel_2021, title = {A novel characteristic of a phytoplankton as a potential source of straight-chain alkanes}, journal = {Scientific Reports}, volume = {11}, number = {1}, year = {2021}, note = {Bandiera_abtest: a Cc_license_type: cc_by Cg_type: Nature Research Journals Number: 1 Primary_atype: Research Publisher: Nature Publishing Group Subject_term: Biofuels;Biological techniques Subject_term_id: biofuels;biological-techniques}, pages = {14190}, abstract = {Biosynthesis of hydrocarbons is a promising approach for the production of alternative sources of energy because of the emerging need to reduce global consumption of fossil fuels. However, the suitability of biogenic hydrocarbons as fuels is limited because their range of the number of carbon atoms is small, and/or they contain unsaturated carbon bonds. Here, we report that a marine phytoplankton, Dicrateria rotunda, collected from the western Arctic Ocean, can synthesize a series of saturated hydrocarbons (n-alkanes) from C10H22 to C38H78, which are categorized as petrol (C10{\textendash}C15), diesel oils (C16{\textendash}C20), and fuel oils (C21{\textendash}C38). The observation that these n-alkanes were also produced by ten other cultivated strains of Dicrateria collected from the Atlantic and Pacific oceans suggests that this capability is a common characteristic of Dicrateria. We also identified that the total contents of the n-alkanes in the Arctic D. rotunda strain increased under dark and nitrogen-deficient conditions. The unique characteristic of D. rotunda could contribute to the development of a new approach for the biosynthesis of n-alkanes.}, keywords = {RCC3437, RCC4217, RCC4577, RCC4578, RCC5635, RCC5639}, issn = {2045-2322}, doi = {10.1038/s41598-021-93204-w}, url = {http://www.nature.com/articles/s41598-021-93204-w}, author = {Harada, Naomi and Hirose, Yuu and Chihong, Song and Kurita, Hirofumi and Sato, Miyako and Onodera, Jonaotaro and Murata, Kazuyoshi and Itoh, Fumihiro} } @article {Helliwell2020, title = {A novel single-domain Na +-selective voltage-gated channel in photosynthetic eukaryotes}, journal = {bioRxiv}, year = {2020}, note = {Publisher: Cold Spring Harbor Laboratory tex.mendeley-tags: RCC1456}, month = {apr}, pages = {2020.04.29.068528}, abstract = {The evolution of Na+-selective four-domain voltage-gated channels (4D-Navs) in animals allowed rapid Na+-dependent electrical excitability, and enabled the development of sophisticated systems for rapid and long-range signalling. Whilst bacteria encode single-domain Na+-selective voltage-gated channels (BacNav), they typically exhibit much slower kinetics than 4D-Navs, and are not thought to have crossed the prokaryote-eukaryote boundary. As such, the capacity for rapid Na+-selective signalling is considered to be confined to certain animal taxa, and absent from photosynthetic eukaryotes. Certainly, in land plants, such as the Venus Flytrap where fast electrical excitability has been described, this is most likely based on fast anion channels. Here, we report a unique class of eukaryotic Na+-selective single-domain channels (EukCatBs) that are present primarily in haptophyte algae, including the ecologically important calcifying coccolithophores. The EukCatB channels exhibit very rapid voltage-dependent activation and inactivation kinetics, and sensitivity to the highly selective 4D-Nav blocker tetrodotoxin. The results demonstrate that the capacity for rapid Na+-based signalling in eukaryotes is not restricted to animals or to the presence of 4D-Navs. The EukCatB channels therefore represent an independent evolution of fast Na+-based electrical signalling in eukaryotes that likely contribute to sophisticated cellular control mechanisms operating on very short time scales in unicellular algae. One Sentence Summary The capacity for rapid Na+-based signalling has evolved in ecologically important coccolithophore species via a novel class of voltage-gated Na+ channels, EukCatBs.}, keywords = {RCC1456}, doi = {10.1101/2020.04.29.068528}, url = {https://doi.org/10.1101/2020.04.29.068528}, author = {Helliwell, Katherine E and Chrachri, Abdul and Koester, Julie and Wharam, Susan and Wheeler, Glen L and Brownlee, Colin} } @article {Iglesias2019, title = {NMR characterization and evaluation of antibacterial and antiobiofilm activity of organic extracts from stationary phase batch cultures of five marine microalgae (Dunaliella sp., D. salina, Chaetoceros calcitrans, C. gracilis and Tisochrysis lutea)}, journal = {Phytochemistry}, volume = {164}, number = {April}, year = {2019}, note = {Publisher: Elsevier tex.mendeley-tags: RCC1349,RCC1811,RCC3579,RCC5,RCC5953}, month = {aug}, pages = {192{\textendash}205}, keywords = {Antibacterial, Antibiofilm, Chaetoceros, Dunaliella, Metabolite identification, NMR, RCC1349, RCC1811, RCC3579, RCC5, RCC5953, Tisochrysis}, issn = {00319422}, doi = {10.1016/j.phytochem.2019.05.001}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0031942219300184}, author = {Iglesias, Ma Jos{\'e} and Soengas, Raquel and Probert, Ian and Guilloud, Emilie and Gourvil, Priscillia and Mehiri, Mohamed and L{\'o}pez, Yuly and Cepas, Virginio and Guti{\'e}rrez-del-R{\'\i}o, Ignacio and Redondo-Blanco, Sa{\'u}l and Villar, Claudio J. and Lomb{\'o}, Felipe and Soto, Sara and Ortiz, Fernando L{\'o}pez} } @article {Liefer2018, title = {Nitrogen starvation induces distinct photosynthetic responses and recovery dynamics in diatoms and prasinophytes}, journal = {PLOS ONE}, volume = {13}, number = {4}, year = {2018}, note = {ISBN: 1111111111 tex.mendeley-tags: RCC745}, month = {apr}, pages = {e0195705}, abstract = {Nitrogen stress is an important control on the growth of phytoplankton and varying responses to this common condition among taxa may affect their relative success within phytoplankton communities.We analyzed photosynthetic responses to nitrogen (N) stress in two classes of phytoplankton that often dominate their respective size ranges, diatoms and prasinophytes, selecting species of distinct niches within each class. Changes in photosynthetic structures appeared similar within each class during N stress, but photophysiological and growth responses were more species -or niche-specific. In the coastal diatom Thalassiosira pseudonana and the oceanic diatom T. weissflogii, N starvation induced large declines in photosynthetic pigments and Photosystem II (PSII) quantity and activity as well as increases in the effective absorption cross-section of PSII photochemistry (σ{\textquoteright}PSII). These diatoms also increased photoprotection through energy-dependent non-photochemical quenching (NPQ) during N starvation. Resupply of N in diatoms caused rapid recovery of growth and relaxation of NPQ, while recovery of PSII photochemistry was slower. In contrast, the prasinophytes Micromonas sp., an Arctic Ocean species, and Ostreococcus tauri, a temperate coastal eutrophile, showed little change in photosynthetic pigments and structures and a decline or no change, respectively, inσ{\textquoteright}PSII with N starvation. Growth and PSII function recovered quickly in Micromonas sp. after resupply of N while O. tauri failed to recover N-replete levels of electron transfer from PSII and growth, possibly due to their distinct photoprotective strategies. O. tauri induced energy-dependent NPQ for photoprotection that may suit its variable and nutrient-rich habitat. Micromonas sp. relies upon both energy-dependent NPQ and a sustained, energy-independent NPQ mechanism. A strategy in Micromonas sp. that permits photoprotection with little change in photosynthetic structures is consistent with its Arctic niche, where low temperatures and thus low biosynthetic rates create higher opportunity costs to rebuild photosynthetic structures.}, keywords = {RCC745}, issn = {1932-6203}, doi = {10.1371/journal.pone.0195705}, url = {http://dx.plos.org/10.1371/journal.pone.0195705}, author = {Liefer, Justin D and Garg, Aneri and Campbell, Douglas A and Irwin, Andrew J and Finkel, Zoe V}, editor = {Ianora, Adrianna} } @article {Partensky2018, title = {A novel species of the marine cyanobacterium Acaryochloris with a unique pigment content and lifestyle}, journal = {Scientific Reports}, volume = {8}, number = {1}, year = {2018}, note = {tex.mendeley-tags: RCC1774}, month = {dec}, pages = {9142}, keywords = {RCC1774}, issn = {2045-2322}, doi = {10.1038/s41598-018-27542-7}, url = {http://www.nature.com/articles/s41598-018-27542-7}, author = {Partensky, Fr{\'e}d{\'e}ric and Six, Christophe and Ratin, Morgane and Garczarek, Laurence and Vaulot, Daniel and Probert, Ian and Calteau, Alexandra and Gourvil, Priscillia and Marie, Dominique and Gr{\'e}bert, Th{\'e}ophile and Bouchier, Christiane and Le Panse, Sophie and Gachenot, Martin and Rodr{\'\i}guez, Francisco and Garrido, Jos{\'e} L.} } @article {Engesmo2016, title = {New insights into the morphology and phylogeny of Heterosigma akashiwo (Raphidophyceae), with the description of Heterosigma minor sp. nov .}, journal = {Phycologia}, volume = {55}, number = {3}, year = {2016}, note = {tex.mendeley-tags: 2016,rcc1501,rcc1502}, month = {may}, pages = {279{\textendash}294}, keywords = {2016, rcc1501, rcc1502}, issn = {0031-8884}, doi = {10.2216/15-115.1}, url = {http://www.phycologia.org/doi/10.2216/15-115.1}, author = {Engesmo, Anette and Eikrem, Wenche and Seoane, Sergio and Smith, Kirsty and Edvardsen, Bente and Hofgaard, Antje and Tomas, Carmelo R.} } @article {MartinezMartinez2015, title = {New lipid envelope-containing dsDNA virus isolates infecting Micromonas pusilla reveal a separate phylogenetic group}, journal = {Aquatic Microbial Ecology}, volume = {74}, year = {2015}, note = {tex.mendeley-tags: rcc}, pages = {17{\textendash}28}, abstract = {Viral infection of phytoplankton has major implications for biochemical and energy cycles, community dynamics, and microbial evolution in the marine environment. The non-bloom forming picoplankter Micromonas pusilla, a significant component of the plankton community worldwide, is known to be susceptible to infection by both dsDNA and dsRNA viruses. Logically, comprehensive knowledge of the ecology of M. pusilla requires a better understanding of the div - ersity and infection mechanisms of their viruses. Here, we investigated 19 new M. pusilla-specific viruses (MpVs) isolated from different locations and years. We performed partial characterization of those MpVs including structural characteristics, genome size, phylogenetic analysis based on partial DNA polymerase gene sequences, host range, and stability at different temperatures and upon exposure to chloroform. Combined, these characteristics allowed classification of the MpVs into 2 groups. Exposure to chloroform led to loss of infectivity by all MpVs in one group, which sug- gests the presence of an outer lipid envelope. In addition, all except one of the members in that group formed a monophylogenetic clade that was distinct from all other MpV isolates. The distinc- tive characteristics of the 2 MpV groups suggest different infection strategies, which may have im- portant implications for the ecology of both host and virus populations in the environment. Knowl- edge gained from our study adds value to the MpV isolates as a scientific resource as it will aid in developing and testing in the laboratory new hypotheses about the ecological and biogeochemical implications of M. pusilla viral infection in the environment}, keywords = {characterization, micromonas pusilla, ncldv, phycodnaviridae, rcc, RCC?o?dd, virus diversity}, issn = {0948-3055}, doi = {10.3354/ame01723}, url = {http://www.int-res.com/abstracts/ame/v74/n1/p17-28/}, author = {Mart{\'\i}nez Mart{\'\i}nez, J and Boere, A and Gilg, I and van Lent, Jwm and Witte, Hj and van Bleijswijk, Jdl and Brussaard, Cpd} } @article {Morrissey2014, title = {A novel protein, ubiquitous in marine phytoplankton, concentrates iron at the cell surface and facilitates uptake}, journal = {Current Biology}, volume = {25}, number = {3}, year = {2014}, note = {tex.mendeley-tags: rcc}, month = {dec}, pages = {364{\textendash}371}, abstract = {Numerous cellular functions including respiration require iron. Plants and phytoplankton must also maintain the iron-rich photosynthetic electron transport chain, which most likely evolved in the iron-replete reducing environments of the Proterozoic ocean [1]. Iron bioavailability has drastically decreased in the contemporary ocean [1], most likely selecting for the evolution of efficient iron acquisition mechanisms among modern phytoplankton. Mesoscale iron fertilization experiments often result in blooms dominated by diatoms [2], indicating that diatoms have adaptations that allow survival in iron-limited waters and rapid multiplication when iron becomes available. Yet the genetic and molecular bases are unclear, as very few iron uptake genes have been functionally characterized from marine eukaryotic phytoplankton, and large portions of diatom iron starvation transcriptomes are genes encoding unknown functions [3{\textendash}5]. Here we show that the marine diatom Phaeodactylum tricornutum utilizes ISIP2a to concentrate Fe(III) at the cell surface as part of a novel, copper-independent and thermodynamically controlled iron uptake system. ISIP2a is expressed in response to iron limitation several days prior to the induction of ferrireductase activity, and it facilitates significant Fe(III) uptake during the initial response to Fe limitation. ISIP2a is able to directly bind Fe(III) and increase iron uptake when heterologously expressed, whereas knockdown of ISIP2a in P. tricornutum decreases iron uptake, resulting in impaired growth and chlorosis during iron limitation. ISIP2a is expressed by diverse marine phytoplankton, indicating that it is an ecologically significant adaptation to the unique nutrient composition of marine environments.}, keywords = {rcc}, issn = {09609822}, doi = {10.1016/j.cub.2014.12.004}, url = {http://www.sciencedirect.com/science/article/pii/S0960982214015632}, author = {Morrissey, Joe and Sutak, Robert and Paz-Yepes, Javier and Tanaka, Atsuko and Moustafa, Ahmed and Veluchamy, Alaguraj and Thomas, Yann and Botebol, Hugo and Bouget, Fran{\c c}ois-Yves and McQuaid, Jeffrey B. and Tirichine, Leila and Allen, Andrew E. and Lesuisse, Emmanuel and Bowler, Chris} } @article {Hagino2011, title = {New evidence for morphological and genetic variation in the cosmopolitan coccolithophore Emiliana huxleyi (prymnesiophyceae) from the cox1b-ATP4 genes}, journal = {Journal of Phycology}, volume = {47}, year = {2011}, note = {tex.mendeley-tags: 2011,rcc,sbr?hyto?ppo}, pages = {1164{\textendash}1176}, abstract = {Emiliania huxleyi (Lohmann) Hay et Mohler is a cosmopolitan coccolithophore occurring from tropical to subpolar waters and exhibiting variations in morphology of coccoliths possibly related to environmental conditions. We examined morphological characters of coccoliths and partial mitochondrial sequences of the cytochrome oxidase 1b (cox1b) through adenosine triphosphate synthase 4 (atp4) genes of thirty-nine clonal E. huxleyi strains from the Atlantic and Pacific Oceans, Mediterranean Sea and their adjacent seas. Based on the morphological study of culture strains by SEM, Type O, a new morphotype characterized by coccoliths with an open central area, was separated from existing morphotypes A, B, B/C, C, R and var. corona, characterized by coccoliths with central area elements. Molecular phylogenetic studies revealed that E. huxleyi consists of at least two mitochondrial sequence groups with different temperature preferences/tolerances: a cool water group occurring in subarctic North Atlantic and Pacific and a warm water group occurring in the sub-tropical Atlantic and Pacific and in the Mediterranean Sea.}, keywords = {2011, rcc, SBR$_\textrmP$hyto$_\textrmE$PPO, sbr?hyto?ppo}, doi = {10.1111/j.1529-8817.2011.01053.x}, author = {Hagino, K and Bendif, El Mahdi and Young, J and Kogame, K and Takano, Y and Probert, I and Horiguchi, T and de Vargas, C and Okada, H} } @article {Gobler2011, title = {Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108}, number = {11}, year = {2011}, note = {ISBN: 0027-8424 tex.mendeley-tags: RCC,rcc}, pages = {4352{\textendash}4357}, abstract = {Harmful algal blooms (HABs) cause significant economic and ecological damage worldwide. Despite considerable efforts, a comprehensive understanding of the factors that promote these blooms has been lacking, because the biochemical pathways that facilitate their dominance relative to other phytoplankton within specific environments have not been identified. Here, biogeochemical measurements showed that the harmful alga Aureococcus anophagefferens outcompeted co-occurring phytoplankton in estuaries with elevated levels of dissolved organic matter and turbidity and low levels of dissolved inorganic nitrogen. We subsequently sequenced the genome of A. anophagefferens and compared its gene complement with those of six competing phytoplankton species identified through metaproteomics. Using an ecogenomic approach, we specifically focused on gene sets that may facilitate dominance within the environmental conditions present during blooms. A. anophagefferens possesses a larger genome (56 Mbp) and has more genes involved in light harvesting, organic carbon and nitrogen use, and encoding selenium-and metal-requiring enzymes than competing phytoplankton. Genes for the synthesis of microbial deterrents likely permit the proliferation of this species, with reduced mortality losses during blooms. Collectively, these findings suggest that anthropogenic activities resulting in elevated levels of turbidity, organic matter, and metals have opened a niche within coastal ecosystems that ideally suits the unique genetic capacity of A. anophagefferens and thus, has facilitated the proliferation of this and potentially other HABs.}, keywords = {brown-tide blooms, comparative genomics, eutrophication, evolution, genome, genomics, long-island, marine-phytoplankton, multidrug, proteins, proteome, rcc, repeat, responses, san-francisco bay, signal-transduction, transporters}, doi = {10.1073/pnas.1016106108}, author = {Gobler, C J and Berry, D L and Dyhrman, S T and Wilhelm, S W and Salamov, A and Lobanov, A V and Zhang, Y and Collier, J L and Wurch, L L and Kustka, A B and Dill, B D and Shah, M and VerBerkmoes, N C and Kuo, A and Terry, A and Pangilinan, J and Lindquist, E A and Lucas, S and Paulsen, I T and Hattenrath-Lehmann, T K and Talmage, S C and Walker, E A and Koch, F and Burson, A M and Marcoval, M A and Tang, Y Z and LeCleir, G R and Coyne, K J and Berg, G M and Bertrand, E M and Saito, M A and Gladyshev, V N and Grigoriev, I V} } @article {Mohr2010, title = {A new chlorophyll d -containing cyanobacterium : evidence for niche adaptation in the genus Acaryochloris}, journal = {The ISME journal}, year = {2010}, note = {tex.mendeley-tags: RCC,RCC1983,rcc}, pages = {1456{\textendash}1469}, abstract = {Chlorophyll d is a photosynthetic pigment that, based on chemical analyses, has only recently been recognized to be widespread in oceanic and lacustrine environments. However, the diversity of organisms harbouring this pigment is not known. Until now, the unicellular cyanobacterium Acaryochloris marina is the only characterized organism that uses chlorophyll d as a major photopigment. In this study we describe a new cyanobacterium possessing a high amount of chlorophyll d, which was isolated from waters around Heron Island, Great Barrier Reef (231 260 31.200 S, 1511 540 50.400 E). The 16S ribosomal RNA is 2\% divergent from the two previously described isolates of A. marina, which were isolated from waters around the Palau islands (Pacific Ocean) and the Salton Sea lake (California), suggesting that it belongs to a different clade within the genus Acaryochloris. An overview sequence analysis of its genome based on Illumina technology yielded 871 contigs with an accumulated length of 8 371965nt. Their analysis revealed typical features associated with Acaryochloris, such as an extended gene family for chlorophyll-binding proteins. However, compared with A. marina MBIC11017, distinct genetic, morphological and physiological differences were observed. Light saturation is reached at lower light intensities, Chl d/a ratios are less variable with light intensity and the phycobiliprotein phycocyanin is lacking, suggesting that cyanobacteria of the genus Acaryochloris occur in distinct ecotypes. These data characterize Acaryochloris as a niche-adapted cyanobacterium and show that more rigorous attempts are worthwhile to isolate, cultivate and analyse chlorophyll d-containing cyanobacteria for understanding the ecophysiology of these organisms. The}, keywords = {acaryochloris, chlorophyll d, coral reef, cyanobacteria, microbial diversity, overview, rcc, RCC1983}, doi = {10.1038/ismej.2010.67}, author = {Mohr, Remus and Schliep, Martin and Kurz, Thorsten and Maldener, Iris and Adams, David G and Larkum, Anthony D W and Chen, Min and Hess, Wolfgang R} } @article {Descles2008, title = {New tools for labeling silica in living diatoms}, journal = {New Phytologist}, volume = {177}, number = {3}, year = {2008}, note = {ISBN: 0028-646X tex.mendeley-tags: rcc}, pages = {822{\textendash}829}, abstract = {Silicon biomineralization is a widespread mechanism found in several kingdoms that concerns both unicellular and multicellular organisms. As a result of genomic and molecular tools, diatoms have emerged as a good model for biomineralization studies and have provided most of the current knowledge on this process. However, the number of techniques available to study its dynamics at the cellular level is still rather limited. Here, new probes were developed specifically to label the pre-existing or the newly synthesized silica frustule of several diatoms species. It is shown that the LysoTracker Yellow HCK-123, which can be used to visualize silica frustules with common filter sets, presents an enhanced signal-to-noise ratio and allows details of the frustules to be imaged without of the use of ionophores. It is also demonstrated that methoxysilane derivatives can be coupled to fluorescein-5-isothiocyanate (FITC) to preferentially label the silica components of living cells. The coupling of labeling procedures might help to address the challenging question of the process of frustule exocytosis.}, keywords = {3D-imaging, BACILLARIOPHYCEAE, BIOLOGY, biomineralization, DEPOSITION, diatoms, exocytosis, FLUORESCENT, nanopattern, pH, phaeodactylum-tricornutum, PLANTS, rcc, THALASSIOSIRA-PSEUDONANA, ultrastructure, VESICLE}, doi = {10.1111/j.1469-8137.2007.02303.x}, author = {Descles, J and Vartanian, M and El Harrak, A and Quinet, M and Bremond, N and Sapriel, G and Bibette, J and Lopez, P J} } @article {Farinas2006, title = {Natural synchronisation for the study of cell division in the green unicellular alga Ostreococcus tauri}, journal = {Plant Molecular Biology}, volume = {60}, number = {2}, year = {2006}, note = {tex.mendeley-tags: RCC745}, pages = {277{\textendash}292}, abstract = {Ostreococcus tauri (Prasinophyceae) is a marine unicellular green alga which diverged early in the green lineage. The interest of O. tauri as a potential model to study plant cell division is based on its key phylogenetic position, its simple binary division, a very simple cellular organisation and now the availability of the full genome sequence. In addition O. tauri has a minimal yet complete set of cell cycle control genes. Here we show that division can be naturally synchronised by light/dark cycles and that organelles divide before the nucleus. This natural synchronisation, although being only partial, enables the study of the expression of CDKs throughout the cell cycle. The expression patterns of OtCDKA and OtCDKB were determined both at the mRNA and protein levels. The single OtCDKA gene is constantly expressed throughout the cell cycle, whereas OtCDKB is highly regulated and expressed only in S/G2/M phases. More surprisingly, OtCDKA is not phosphorylated at the tyrosine residue, in contrast to OtCDKB which is strongly phosphorylated during cell division. OtCDKA kinase activity appears before the S phase, indicating a possible role of this protein in the G1/S transition. OtCDKB kinase activity occurs later than OtCDKA, and its tyrosine phosphorylation is correlated to G2/M, suggesting a possible control of the mitotic activity. To our knowledge this is the first organism in the green lineage which showed CDKB tyrosine phosphorylation during cell cycle progression.}, keywords = {Cyclin-dependent kinases, Green alga, Histone H1 kinase activity, Ostreococcus tauri, Phosphorylation, RCC745, Synchronisation of the cell division}, issn = {01674412}, doi = {10.1007/s11103-005-4066-1}, author = {Farinas, Beno{\^\i}t and Mary, Camille and De O Manes, Carmem Lara and Bhaud, Yvonne and Peaucellier, G{\'e}rard and Moreau, Herv{\'e}} } @article {Six2005a, title = {New insights into the nature and phylogeny of prasinophyte antenna proteins: Ostreococcus tauri, a case study}, journal = {Molecular Biology and Evolution}, volume = {22}, number = {11}, year = {2005}, note = {tex.mendeley-tags: RCC113,RCC114,RCC745: RCC417}, pages = {2217{\textendash}2230}, abstract = {The basal position of the Mamiellales (Prasinophyceae) within the green lineage makes these unicellular organisms key to elucidating early stages in the evolution of chlorophyll a/b{\textendash}binding light-harvesting complexes (LHCs). Here, we unveil the complete and unexpected diversity of Lhc proteins in Ostreococcus tauri, a member of the Mamiellales order, based on results from complete genome sequencing. Like Mantoniella squamata, O. tauri possesses a number of genes encoding an unusual prasinophyte-specific Lhc protein type herein designated "Lhcp". Biochemical characterization of the complexes revealed that these polypeptides, which bind chlorophylls a, b, and a chlorophyll c{\textendash}like pigment (Mg-2,4-divinyl-phaeoporphyrin a5 monomethyl ester) as well as a number of unusual carotenoids, are likely predominant. They are retrieved to some extent in both reaction center I (RCI){\textendash} and RCII-enriched fractions, suggesting a possible association to both photosystems. However, in sharp contrast to previous reports on LHCs of M. squamata, O. tauri also possesses other LHC subpopulations, including LHCI proteins (encoded by five distinct Lhca genes) and the minor LHCII polypeptides, CP26 and CP29. Using an antibody against plant Lhca2, we unambiguously show that LHCI proteins are present not only in O. tauri, in which they are likely associated to RCI, but also in other Mamiellales, including M. squamata. With the exception of Lhcp genes, all the identified Lhc genes are present in single copy only. Overall, the discovery of LHCI proteins in these prasinophytes, combined with the lack of the major LHCII polypeptides found in higher plants or other green algae, supports the hypothesis that the latter proteins appeared subsequent to LHCI proteins. The major LHC of prasinophytes might have arisen prior to the LHCII of other chlorophyll a/b{\textendash}containing organisms, possibly by divergence of a LHCI gene precursor. However, the discovery in O. tauri of CP26-like proteins, phylogenetically placed at the base of the major LHCII protein clades, yields new insight to the origin of these antenna proteins, which have evolved separately in higher plants and green algae. Its diverse but numerically limited suite of Lhc genes renders O. tauri an exceptional model system for future research on the evolution and function of LHC components.}, keywords = {rcc, RCC113, RCC114, RCC417, RCC745, SBR$_\textrmP$hyto$_\textrmD$PO}, doi = {10.1093/molbev/msi220}, author = {Six, C and Worden, A Z and Rodriguez, F and Moreau, H and Partensky, F} } @article {Chretiennot-Dinet1995, title = {A new marine picoeucaryote: Ostreococcus tauri gen. et sp. nov. (Chlorophyta, Prasinophyceae)}, journal = {Phycologia}, volume = {34}, number = {4}, year = {1995}, note = {tex.mendeley-tags: RCC745}, pages = {285{\textendash}292}, keywords = {FRESH-WATER ECOSYSTEMS, morphology, picoplankton, pigments, PROCHLOROCOCCUS-MARINUS, Prokaryote, rcc, RCC745, Size}, doi = {10.2216/i0031-8884-34-4-285.1}, author = {Chr{\'e}tiennot-Dinet, M.-J. and Courties, C and Vaquer, A and Neveux, J and Claustre, H and Lautier, J and Machado, M C} }