@article {wang_meta-analysis_2024, title = {Meta-analysis reveals responses of coccolithophores and diatoms to warming}, journal = {Marine Environmental Research}, volume = {193}, year = {2024}, pages = {106275}, abstract = {A meta-analysis was conducted to explore the effects of warming on the physiological processes of coccolitho- phores and diatoms by synthesizing a large number of published literatures. A total of 154 studies consisting 301 experiments were synthesized in this study. Under a projected temperature increase of 3{\textendash}5 {\textopenbullet}C by IPCC AR6 at the end of this century, our results suggest that the growth and photosynthetic rate of coccolithophores were significantly enhanced by the rising temperature, while the calcification of coccolithophores was only slightly promoted. Warming also had significantly positive effects on the growth but not photosynthesis of diatoms. In comparison, the effect size of warming on the growth rate of coccolithophores was larger than that of diatoms. However, there was no significant effect of warming on either the ratio of particulate inorganic carbon to par- ticulate organic carbon (PIC:POC) of coccolithophores or the ratio of biogenic silica to carbon (BSi:C) of diatoms. Furthermore, the results reveal latitudinal and size-specific patterns of the effect sizes of warming. For diatoms, the effects of warming on growth were more prominent in high latitudes, specifically for the Southern Hemi- sphere species. In addition, the effect size of warming on the small-sized diatoms was larger than that of the large-sized diatoms. For coccolithophores, the growth of the Southern Hemisphere temperate strains was significantly promoted by warming. Overall, the results based on the meta-analysis indicate that the projected warming of the end of this century will be more favor to the growth of coccolithophores than that of diatoms, thus potentially affect the competitive advantages of coccolithophores over diatoms; while the mid-to high latitude species/strains of both coccolithophores and diatoms will benefit more than their counterparts in the lower latitudes. Therefore, this study offers novel insights into predicting both the inter- and intra-group competitive advantages of diatoms and coccolithophores under the future warming climate change scenario.}, keywords = {rcc1238}, issn = {01411136}, doi = {10.1016/j.marenvres.2023.106275}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0141113623004038}, author = {Wang, Jiawei and Zeng, Cong and Feng, Yuanyuan} } @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 {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 {bordiga_unexpected_2023, title = {Unexpected silicon localization in calcium carbonate exoskeleton of cultured and fossil coccolithophores}, journal = {Scientific Reports}, volume = {13}, number = {1}, year = {2023}, note = {Number: 1 Publisher: Nature Publishing Group}, month = {may}, pages = {7417}, abstract = {Coccolithophores, marine calcifying phytoplankton, are important primary producers impacting the global carbon cycle at different timescales. Their biomineral structures, the calcite containing coccoliths, are among the most elaborate hard parts of any organism. Understanding the morphogenesis of coccoliths is not only relevant in the context of coccolithophore eco-physiology but will also inform biomineralization and crystal design research more generally. The recent discovery of a silicon (Si) requirement for crystal shaping in some coccolithophores has opened up a new avenue of biomineralization research. In order to develop a mechanistic understanding of the role of Si, the presence and localization of this chemical element in coccoliths needs to be known. Here, we document for the first time the uneven Si distribution in Helicosphaera carteri coccoliths through three synchrotron-based techniques employing X-ray Fluorescence and Infrared Spectromicroscopy. The enrichment of Si in specific areas of the coccoliths point to a targeted role of this element in the coccolith formation. Our findings mark a key step in biomineralization research because it opens the door for a detailed mechanistic understanding of the role Si plays in shaping coccolith crystals.}, keywords = {Biogeochemistry, Marine biology, Palaeontology, RCC1323}, issn = {2045-2322}, doi = {10.1038/s41598-023-34003-3}, url = {https://www.nature.com/articles/s41598-023-34003-3}, author = {Bordiga, M. and Lupi, C. and Langer, G. and Gianoncelli, A. and Birarda, G. and Pollastri, S. and Bonanni, V. and Bedolla, D. E. and Vaccari, L. and Gariani, G. and Cerino, F. and Cabrini, M. and Beran, A. and Zuccotti, M. and Fiorentino, G. and Zanoni, M. and Garagna, S. and Cobianchi, M. and Di Giulio, A.} } @article {sorokina_draft_2022, title = {Draft genome assembly and sequencing dataset of the marine diatom Skeletonema costatum RCC75}, journal = {Data in Brief}, year = {2022}, month = {feb}, pages = {107931}, abstract = {Diatoms (Bacillariophyceae) are a major constituent of the phytoplankton and have a universally recognized ecological importance. Between 1,000 and 1,300 diatom genera have been described in the literature, but only 10 nuclear genomes have been published and made available to the public up to date. Skeletonema costatum is a cosmopolitan marine diatom, principally occurring in coastal regions, and is one of the most abundant members of the Skeletonema genus. Here we present a draft assembly of the Skeletonema costatum RCC75 genome, obtained from PacBio and Illumina NovaSeq data. This dataset will expand the knowledge of the Bacillariophyceae genetics and contribute to the global understanding of phytoplankton{\textquoteright}s physiological, ecological, and environmental functioning.}, keywords = {Algal genome, BACILLARIOPHYCEAE, diatoms, genome sequencing, Illumina sequencing, PacBio sequencing, RCC75}, issn = {2352-3409}, doi = {10.1016/j.dib.2022.107931}, url = {https://www.sciencedirect.com/science/article/pii/S2352340922001433}, author = {Sorokina, Maria and Barth, Emanuel and Zulfiqar, Mahnoor and Kwantes, Michiel and Pohnert, Georg and Steinbeck, Christoph} } @article {zhang_intense_2022, title = {Intense blooms of Phaeocystis globosa in the South China Sea are caused by a unique {\textquotedblleft}giant-colony{\textquotedblright} ecotype}, journal = {Harmful Algae}, volume = {114}, year = {2022}, pages = {102227}, abstract = {The haptophyte Phaeocystis globosa, an important causative agent of harmful algal blooms globally, exhibits varying morphological and physiological features and high genetic diversity, yet the relationship among these has never been elucidated. In this study, colony sizes and pigment profiles of 19 P. globosa isolates from the Pacific and Atlantic Oceans were determined. Genetic divergence of these strains was analyzed using the chloroplast rbcS-rpl27 intergenic spacer, a novel high-resolution molecular marker. Strains could be divided into four genetic clades based on these sequences, or two groups based on colony size and the identity of diagnostic pigments (19{\textquoteright}-hexanoyloxyfucoxanthin, hex-fuco, and 19{\textquoteright}-butanoyloxyfucoxanthin, but-fuco). Three strains from the South China Sea (SCS), all belonging to the same genetic clade, have unique biological features in forming giant colonies and possessing but-fuco as their diagnostic pigment. Based on these findings, we propose that these SCS strains should be a unique {\textquotedblleft}giant-colony{\textquotedblright} ecotype of P. globosa. During the period 2016-2021, more than 1000 rbcS-rpl27 sequences were obtained from 16 P. globosa colony samples and 18 phytoplankton samples containing solitary P. globosa cells in the SCS. Phylogenetic analysis indicated that >95\% of the sequences from P. globosa colonies in the SCS were comprised of the {\textquotedblleft}giant-colony{\textquotedblright} ecotype, whereas the genetic diversity of solitary cells was much higher. Results demonstrated that intense blooms of P. globosa featuring giant colonies in the SCS were mainly caused by this giant-colony P. globosa ecotype.}, keywords = {ecotype, genetic diversity, Giant colony, Marker pigment, RCC1736, RCC2055, RCC678, RCC736}, issn = {1568-9883}, doi = {10.1016/j.hal.2022.102227}, url = {https://www.sciencedirect.com/science/article/pii/S1568988322000555}, author = {Zhang, Qing-Chun and Liu, Chao and Wang, Jin-Xiu and Kong, Fan-Zhou and Niu, Zhuang and Xiang, Ling and Yu, Ren-Cheng} } @article {gomez_molecular_2022, title = {Molecular phylogeny of the spiny-surfaced species of the dinoflagellate Prorocentrum with the description of P. Thermophilum sp. nov. and P. criophilum sp. nov. (Prorocentrales, Dinophyceae)}, journal = {Journal of Phycology}, volume = {n/a}, number = {n/a}, year = {2022}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jpy.13298}, abstract = {Spiny-surfaced species of Prorocentrum forms harmful algal blooms, and its taxonomic identity is obscure due to the size and shape variability. Molecular phylogenies reveal two major clades: one for P. cordatum with sequences mainly retrieved as P. minimum, and other for P. shikokuense with sequences also retrieved as P. dentatum and P. donghaiense. Several closely related clades still need to be characterized. Here, we provide SSU- and LSU rRNA, and ITS gene sequences of the strain CCMP3122 isolated from Florida (initially named P. donghaiense) and strains Prorocentrum sp. RCC6871{\textendash}2 from the Ross Sea, Antarctica. We describe Prorocentrum thermophilum sp. nov. based on the strain CCMP3122, a species also distributed in the open waters of Gulf of Mexico, New Zealand and the Arabian Gulf; and Prorocentrum criophilum sp. nov. based on the strain RCC6872, which is distributed in the Antarctic Ocean and the Arctic Sea. Prorocentrum thermophilum is roundish ( 14 μm long, 12 μm wide), with an inconspicuous anterior spine-like prolongation under light microscopy, valves with tiny, short knobs (5{\textendash}7 per μm2), and several (<7) large trichocyst pores ( 0.3 μm) in the right valve, as well as smaller pores ( 0.15 μm). Prorocentrum criophilum is round in valve view ( 11 μm long, 10 μm wide) and asymmetrically roundish in lateral view, the periflagellar area was not discernible under light microscopy, valves with very tiny, short knobs (6{\textendash}10 per μm2), and at least twelve large pores in the right valve. Other potentially undescribed species of spiny-surfaced Prorocentrum are discussed}, keywords = {Dinophyta, HABs, harmful algae blooms, molecular phylogenetics, new species, Prorocentraceae, RCC6871, RCC6872, taxonomy}, issn = {1529-8817}, doi = {10.1111/jpy.13298}, url = {http://onlinelibrary.wiley.com/doi/abs/10.1111/jpy.13298}, author = {G{\'o}mez, Fernando and Gourvil, Priscillia and Li, Tangcheng and Huang, Yulin and Zhang, Huan and Courcot, Lucie and Artigas, Luis F. and Soler On{\'\i}s, Emilio and Gutierrez-Rodriguez, Andres and Lin, Senjie} } @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 {liu_phycosphere_2022, title = {Phycosphere pH of unicellular nano- and micro- phytoplankton cells and consequences for iron speciation}, journal = {The ISME Journal}, volume = {16}, number = {10}, year = {2022}, note = {Number: 10 Publisher: Nature Publishing Group}, month = {oct}, pages = {2329{\textendash}2336}, abstract = {Surface ocean pH is declining due to anthropogenic atmospheric CO2 uptake with a global decline of \textasciitilde0.3 possible by 2100. Extracellular pH influences a range of biological processes, including nutrient uptake, calcification and silicification. However, there are poor constraints on how pH levels in the extracellular microenvironment surrounding phytoplankton cells (the phycosphere) differ from bulk seawater. This adds uncertainty to biological impacts of environmental change. Furthermore, previous modelling work suggests that phycosphere pH of small cells is close to bulk seawater, and this has not been experimentally verified. Here we observe under 140 μmol photons{\textperiodcentered}m-2{\textperiodcentered}s-1 the phycosphere pH of Chlamydomonas concordia (5 {\textmu}m diameter), Emiliania huxleyi (5 {\textmu}m), Coscinodiscus radiatus (50 {\textmu}m) and C. wailesii (100 {\textmu}m) are 0.11 {\textpm} 0.07, 0.20 {\textpm} 0.09, 0.41 {\textpm} 0.04 and 0.15 {\textpm} 0.20 (mean {\textpm} SD) higher than bulk seawater (pH 8.00), respectively. Thickness of the pH boundary layer of C. wailesii increases from 18 {\textpm} 4 to 122 {\textpm} 17 {\textmu}m when bulk seawater pH decreases from 8.00 to 7.78. Phycosphere pH is regulated by photosynthesis and extracellular enzymatic transformation of bicarbonate, as well as being influenced by light intensity and seawater pH and buffering capacity. The pH change alters Fe speciation in the phycosphere, and hence Fe availability to phytoplankton is likely better predicted by the phycosphere, rather than bulk seawater. Overall, the precise quantification of chemical conditions in the phycosphere is crucial for assessing the sensitivity of marine phytoplankton to ongoing ocean acidification and Fe limitation in surface oceans.}, keywords = {Biogeochemistry, Microbial biooceanography, RCC1, rcc1731, Water microbiology}, issn = {1751-7370}, doi = {10.1038/s41396-022-01280-1}, url = {https://www.nature.com/articles/s41396-022-01280-1}, author = {Liu, Fengjie and Gledhill, Martha and Tan, Qiao-Guo and Zhu, Kechen and Zhang, Qiong and Sala{\"u}n, Pascal and Tagliabue, Alessandro and Zhang, Yanjun and Weiss, Dominik and Achterberg, Eric P. and Korchev, Yuri} } @article {roux_bacteria_2021, title = {Bacteria enhance the production of extracellular polymeric substances by the green dinoflagellate Lepidodinium chlorophorum}, journal = {Scientific Reports}, volume = {11}, number = {1}, year = {2021}, note = {Number: 1 Publisher: Nature Publishing Group}, pages = {1{\textendash}15}, abstract = {High biomasses of the marine dinoflagellate Lepidodinium chlorophorum cause green seawater discolorations along Southern Brittany (NE Atlantic, France). The viscosity associated to these phenomena has been related to problems in oyster cultivation. The harmful effect of L. chlorophorum might originate from the secretion of Extracellular Polymeric Substances (EPS). To understand whether the EPS are produced by L. chlorophorum or its associated bacteria, or if they are a product of their interaction, batch cultures were performed under non-axenic and pseudo-axenic conditions for three strains. Maximum dinoflagellate cell abundances were observed in pseudo-axenic cultures. The non-sinking fraction of polymers (Soluble Extracellular Polymers, SEP), mainly composed of proteins and the exopolysaccharide sulphated galactan, slightly increased in pseudo-axenic cultures. The amount of Transparent Exopolymer Particles (TEP) per cell increased under non-axenic conditions. Despite the high concentrations of Particulate Organic Carbon (POC) measured, viscosity did not vary. These results suggest that the L. chlorophorum-bacteria interaction could have a detrimental consequence on the dinoflagellate, translating in a negative effect on L. chlorophorum growth, as well as EPS overproduction by the dinoflagellate, at concentrations that should not affect seawater viscosity.}, keywords = {RCC1489}, issn = {2045-2322}, doi = {10.1038/s41598-021-84253-2}, url = {http://www.nature.com/articles/s41598-021-84253-2}, author = {Roux, Pauline and Siano, Raffaele and Collin, Karine and Bilien, Gwenael and Sinquin, Corinne and Marchand, Laetitia and Zykwinska, Agata and Delbarre-Ladrat, Christine and Schapira, Mathilde} } @article {zhang_development_2021, title = {Development of high-resolution chloroplast markers for intraspecific phylogeographic studies of Phaeocystis globosa}, journal = {Journal of Oceanology and Limnology}, volume = {39}, number = {2}, year = {2021}, month = {mar}, pages = {508{\textendash}524}, abstract = {Phaeocystis globosa is an important harmful algal bloom causative species distributing widely in temperate and tropical coastal waters in the world. The morphological, physiological, and biochemical characteristics are different among geographic strains, which can not be distinguished with nuclear ribosomal DNA markers at present. Therefore, the genetic distance and phylogeographic relationships of nuclear 28S rDNA D1{\textendash}D2 and ITS regions, and three chloroplast intergenic spacers (petN-trnS1, trnM1-psbA, and rbcS-rpl27) were analyzed and compared among 13 strains of P. globosa isolated from the Pacific Ocean and Atlantic Ocean in this study. In addition, the nucleotide polymorphisms of 28S rDNA D1{\textendash}D2, ITS, and rbcS-rpl27 regions were evaluated in two P. globosa strains. The various levels of nucleotide polymorphism were in the nuclear 28S rDNA D1{\textendash}D2 region and ITS region, but no polymorphism was in the chloroplast rbcS-rpl27 intergenic spacer. A reasonable intraspecific phylogeographic relationship was presented by rbcS-rpl27 intergenic spacer, which had the strongest distinction to geographic strains compared to those of 28S rDNA D1{\textendash}D2 and ITS regions. In the phylogenetic tree of rbcS-rpl27 intergenic spacer, the two strains from the North Sea of the Atlantic Ocean were divided firstly from the species of P. globosa, and then formed an independent clade, while the other Atlantic strains and all of Pacific strains joined up to build the other clade. It was implied that at least two genetically distant populations of P. globosa existed in the Atlantic coastal regions. This study provided a high-resolution chloroplast marker to analyze intraspecific phylogeographic populations of P. globosa, and preliminarily clarified the genetic relationships of the Pacific and Atlantic strains of P. globosa.}, keywords = {RCC2055, RCC736}, issn = {2096-5508, 2523-3521}, doi = {10.1007/s00343-020-9304-5}, url = {https://link.springer.com/10.1007/s00343-020-9304-5}, author = {Zhang, Qingchun and Niu, Zhuang and Wang, Jinxiu and Liu, Chao and Kong, Fanzhou and Hu, Xiaokun and Zhao, Jiayu and Yu, Rencheng} } @article {xie_disentangling_2021, title = {Disentangling the Effects of Ocean Carbonation and Acidification on Elemental Contents and Macromolecules of the Coccolithophore Emiliania huxleyi}, journal = {Frontiers in Microbiology}, volume = {12}, year = {2021}, pages = {3188}, abstract = {Elemental contents change with shifts in macromolecular composition of marine phytoplankton. Recent studies focus on the responses of elemental contents of coccolithophores, a major calcifying phytoplankton group, to changing carbonate chemistry, caused by the dissolution of anthropogenically derived CO2 into the surface ocean. However, the effects of changing carbonate chemistry on biomacromolecules, such as protein and carbohydrate of coccolithophores, are less documented. Here, we disentangled the effects of elevated dissolved inorganic carbon (DIC) concentration (900 to 4,930μmolkg-1) and reduced pH value (8.04 to 7.70) on physiological rates, elemental contents, and macromolecules of the coccolithophore Emiliania huxleyi. Compared to present DIC concentration and pH value, combinations of high DIC concentration and low pH value (ocean acidification) significantly increased pigments content, particulate organic carbon (POC), and carbohydrate content and had less impact on growth rate, maximal relative electron transport rate (rETRmax), particulate organic nitrogen (PON), and protein content. In high pH treatments, elevated DIC concentration significantly increased growth rate, pigments content, rETRmax, POC, particulate inorganic carbon (PIC), protein, and carbohydrate contents. In low pH treatments, the extents of the increase in growth rate, pigments and carbohydrate content were reduced. Compared to high pH value, under low DIC concentration, low pH value significantly increased POC and PON contents and showed less impact on protein and carbohydrate contents; however, under high DIC concentration, low pH value significantly reduced POC, PON, protein, and carbohydrate contents. These results showed that reduced pH counteracted the positive effects of elevated DIC concentration on growth rate, rETRmax, POC, PON, carbohydrate, and protein contents. Elevated DIC concentration and reduced pH acted synergistically to increase the contribution of carbohydrate{\textendash}carbon to POC, and antagonistically to affect the contribution of protein{\textendash}nitrogen to PON, which further shifted the carbon/nitrogen ratio of E. huxleyi.}, keywords = {rcc, RCC1266}, issn = {1664-302X}, doi = {10.3389/fmicb.2021.737454}, url = {https://www.frontiersin.org/article/10.3389/fmicb.2021.737454}, author = {Xie, Emei and Xu, Kui and Li, Zhengke and Li, Wei and Yi, Xiangqi and Li, Hongzhou and Han, Yonghe and Zhang, Hong and Zhang, Yong} } @article {zhang_growth-dependent_2021, title = {Growth-dependent changes in elemental stoichiometry and macromolecular allocation in the coccolithophore Emiliania huxleyi under different environmental conditions}, journal = {Limnology and Oceanography}, volume = {66}, number = {8}, year = {2021}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/lno.11854}, pages = {2999{\textendash}3009}, abstract = {The growth rate hypothesis (GRH) posits an increase in ribosomal ribonucleic acid (RNA) content, and therefore cellular phosphorus (P), with increasing growth rate. There is evidence that the GRH may not apply to phytoplankton under all conditions. Here, we experimentally controlled four conditions (light, temperature, pH, and CO2) to alter the growth rate of Emiliania huxleyi, a biogeochemically important coccolithophorid, and monitored changes in RNA, protein, and carbohydrate content. We show that an increase in growth rate caused by increasing light, pH, and CO2 resulted in increased RNA per unit of organic carbon (RNA : POC), but that increasing temperature, leading to increase of growth rate, resulted in a decrease in RNA : POC. Protein per unit of organic carbon (protein : POC) increased in our increased temperature, pH, and CO2 treatments that increased growth rate, but there was little change in protein : POC in our light treatment despite it inducing the same increase in growth rate. Carbohydrate per unit of organic carbon (Carbohydrate : POC) increased with growth rate under increased light and CO2 but did not vary significantly in the temperature or pH treatments. These results indicate that physiological acclimation to specific environmental conditions can lead to contrasting patterns in RNA, protein, and carbohydrate composition and therefore contrasting changes in carbon : nitrogen : phosphorus ratios with growth rate in E. huxleyi.}, keywords = {rcc, RCC1266}, issn = {1939-5590}, doi = {10.1002/lno.11854}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/lno.11854}, author = {Zhang, Yong and Li, Zhengke and Schulz, Kai G. and Hu, Yingyu and Irwin, Andrew J. and Finkel, Zoe V.} } @article {tostevin_influence_2021, title = {The influence of elevated SiO2(aq) on intracellular silica uptake and microbial metabolism}, journal = {Geobiology}, volume = {n/a}, number = {n/a}, year = {2021}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/gbi.12442}, abstract = {Microbes are known to accumulate intracellular SiO2(aq) up to 100s of mmol/l from modern seawater (SiO2(aq) <100 {\textmu}mol/l), despite having no known nutrient requirement for Si. Before the evolution of siliceous skeletons, marine silica concentrations were likely an order of magnitude higher than the modern ocean, raising the possibility that intracellular SiO2(aq) accumulation interfered with normal cellular function in non-silicifying algae. Yet, because few culturing studies have isolated the effects of SiO2(aq) at high concentration, the potential impact of elevated marine silica on early microbial evolution is unknown. Here, we test the influence of elevated SiO2(aq) on eukaryotic algae, as well as a prokaryote species. Our results demonstrate that under SiO2(aq) concentrations relevant to ancient seawater, intracellular Si accumulates to concentrations comparable to those found in siliceous algae such as diatoms. In addition, all eukaryotic algae showed a statistically significant response to the high-Si treatment, including reduced average cell sizes and/or a reduction in the maximum growth rate. In contrast, there was no consistent response to the high-Si treatment by the prokaryote species. Our results highlight the possibility that elevated marine SiO2(aq) may have been an environmental stressor during early eukaryotic evolution.}, keywords = {Archaean, culturing, microbial metabolism, Proterozoic, RCC1, RCC1216, rcc1512, RCC1547, rcc539, silica}, issn = {1472-4669}, doi = {10.1111/gbi.12442}, url = {http://onlinelibrary.wiley.com/doi/abs/10.1111/gbi.12442}, author = {Tostevin, Rosalie and Snow, Joseph T. and Zhang, Qiong and Tosca, Nicholas J. and Rickaby, Rosalind E. M.} } @article {zhang_isotope_2021, title = {An isotope label method for empirical detection of carbonic anhydrase in the calcification pathway of the coccolithophore Emiliania huxleyi}, journal = {Geochimica et Cosmochimica Acta}, volume = {292}, year = {2021}, pages = {78{\textendash}93}, abstract = {Coccolithophores are a group of phytoplankton widely distributed in the ocean, which secrete extracellular calcite plates termed coccoliths. Coccoliths have been increasingly employed as an archive for geochemical, ecological and paleoclimate studies in recent years. A robust application of coccolith-based geochemical proxies relies on understanding the carbon acquisition strategies and the pathways of carbon supply for calcification. Carbonic anhydrase (CA) plays important roles in the carbon concentrating mechanism s of aquatic algae and potentially also in calcification. However, it is difficult to independently assess the role of CA in carbon supply for photosynthesis versus calcification. To fill this gap, we explored a new method to detect the CA activity inside coccolithophore. To achieve this, coccolithophores were cultured with oxygen and carbon isotope labeled dissolved inorganic carbon (DIC). By exploiting the different behavior of oxygen and carbon isotopes with (sea)water, this double label method can elucidate the significance of CA activity in the calcification pathway. Application of this method to Emiliania huxleyi shows that CA is present in the calcification pathway, and that there is no significant difference in the CA activity between a high and low CO2 treatment. However, under low CO2 treatment E. huxleyi enhanced the bicarbonate pumping rate on both cell and chloroplast membranes. This novel method could be performed on other species of coccolithophores in the future and have a potential to extend our knowledge on coccolith oxygen isotope vital effects.}, keywords = {Carbonic anhjydrase, ccm, coccolithophore, Isotopic labelling, rcc, rcc1258}, issn = {0016-7037}, doi = {10.1016/j.gca.2020.09.008}, url = {https://www.sciencedirect.com/science/article/pii/S0016703720305597}, author = {Zhang, Hongrui and Blanco-Ameijeiras, Sonia and Hopkinson, Brian M. and Bernasconi, Stefano M. and Mejia, Luz Maria and Liu, Chuanlian and Stoll, Heather} } @article {uwizeye_morphological_2021, title = {Morphological bases of phytoplankton energy management and physiological responses unveiled by 3D subcellular imaging}, journal = {Nature Communications}, volume = {12}, number = {1}, year = {2021}, note = {Number: 1 Publisher: Nature Publishing Group}, month = {feb}, pages = {1{\textendash}12}, abstract = {Phytoplankton account for a large proportion of global primary production and comprise a number of phylogenetically distinct lineages. Here, Uwizeye et al. use FIB-SEM to study ultrastructural plasticity of 7 distinct taxa and describe how subcellular organisation is linked to energy metabolism.}, keywords = {RCC100, RCC4014, RCC827, RCC909}, issn = {2041-1723}, doi = {10.1038/s41467-021-21314-0}, url = {http://www.nature.com/articles/s41467-021-21314-0}, author = {Uwizeye, Clarisse and Decelle, Johan and Jouneau, Pierre-Henri and Flori, Serena and Gallet, Benoit and Keck, Jean-baptiste and Bo, Davide Dal and Moriscot, Christine and Seydoux, Claire and Chevalier, Fabien and Schieber, Nicole L. and Templin, Rachel and Allorent, Guillaume and Courtois, Florence and Curien, Gilles and Schwab, Yannick and Schoehn, Guy and Zeeman, Samuel C. and Falconet, Denis and Finazzi, Giovanni} } @article {Uwizeye2020, title = {In-cell quantitative structural imaging of phytoplankton using 3D electron microscopy}, journal = {bioRxiv}, year = {2020}, note = {tex.mendeley-tags: RCC100,RCC4014,RCC827,RCC909}, month = {jan}, pages = {2020.05.19.104166}, abstract = {Phytoplankton is a minor fraction of the global biomass playing a major role in primary production and climate. Despite improved understanding of phytoplankton diversity and genomics, we lack nanoscale subcellular imaging approaches to understand their physiology and cell biology. Here, we present a complete Focused Ion Beam - Scanning Electron Microscopy (FIB-SEM) workflow (from sample preparation to image processing) to generate nanometric 3D phytoplankton models. Tomograms of entire cells, representatives of six ecologically-successful phytoplankton unicellular eukaryotes, were used for quantitative morphometric analysis. Besides lineage-specific cellular architectures, we observed common features related to cellular energy management: i) conserved cell-volume fractions occupied by the different organelles; ii) consistent plastid-mitochondria interactions, iii) constant volumetric ratios in these energy-producing organelles. We revealed detailed subcellular features related to chromatin organization and to biomineralization. Overall, this approach opens new perspectives to study phytoplankton acclimation responses to abiotic and biotic factors at a relevant biological scale.Competing Interest StatementThe authors have declared no competing interest.}, keywords = {RCC100, RCC4014, RCC827, RCC909}, doi = {10.1101/2020.05.19.104166}, url = {http://biorxiv.org/content/early/2020/05/20/2020.05.19.104166.abstract}, author = {Uwizeye, Clarisse and Decelle, Johan and Jouneau, Pierre-Henri and Gallet, Benoit and Keck, Jean-baptiste and Schwab, Yannick and Schoehn, Guy and Zeeman, Samuel C and Falconet, Denis and Finazzi, Giovanni and Moriscot, Christine and Chevalier, Fabien and Schieber, Nicole L and Templin, Rachel and Curien, Gilles and Schwab, Yannick and Schoehn, Guy and Zeeman, Samuel C and Falconet, Denis and Finazzi, Giovanni} } @article {BlancoAmeijeiras2020, title = {Influence of temperature and CO 2 on Plasma-membrane permeability to CO 2 and HCO 3 - in the marine haptophytes emiliania huxleyi and calcidiscus leptoporus (prymnesiophyceae)}, journal = {Journal of Phycology}, year = {2020}, note = {tex.mendeley-tags: RCC1130,RCC1258}, month = {jun}, pages = {jpy.13017}, abstract = {Membrane permeabilities to CO2 and HCO3- constrain the function of CO2 concentrating mechanisms that algae use to supply inorganic carbon for photosynthesis. In diatoms and green algae, plasma membranes are moderately to highly permeable to CO2 but effectively impermeable to HCO3-. Here, CO2 and HCO3- membrane permeabilities were measured using an 18O-exchange technique on two species of haptophyte algae, Emiliania huxleyi and Calcidiscus leptoporus, which showed that the plasma membranes of these species are also highly permeable to CO2 (0.006{\textendash}0.02 cm ? s-1) but minimally permeable to HCO3-. Increased temperature and CO2 generally increased CO2 membrane permeabilities in both species, possibly due to changes in lipid composition or CO2 channel proteins. Changes in CO2 membrane permeabilities showed no association with the density of calcium carbonate coccoliths surrounding the cell, which could potentially impede passage of compounds. Haptophyte plasma-membrane permeabilities to CO2 were somewhat lower than those of diatoms but generally higher than membrane permeabilities of green algae. One caveat of these measurements is that the model used to interpret 18O-exchange data assumes that carbonic anhydrase, which catalyzes 18O-exchange, is homogeneously distributed in the cell. The implications of this assumption were tested using a two-compartment model with an inhomogeneous distribution of carbonic anhydrase to simulate 18O-exchange data and then inferring plasma-membrane CO2 permeabilities from the simulated data. This analysis showed that the inferred plasma-membrane CO2 permeabilities are minimal estimates but should be quite accurate under most conditions.}, keywords = {carbon concentrating mechanism, CO2, haptophyte, membrane, PERMEABILITY, RCC1130, rcc1258}, issn = {0022-3646}, doi = {10.1111/jpy.13017}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jpy.13017}, author = {Blanco-Ameijeiras, Sonia and Stoll, Heather M. and Zhang, Hongrui and Hopkinson, Brian M.}, editor = {Raven, J.} } @article {Zhang2020, title = {Interactions of thallium with marine phytoplankton}, journal = {Geochimica et Cosmochimica Acta}, volume = {276}, year = {2020}, note = {Publisher: The Author(s) tex.mendeley-tags: RCC1,RCC1242,RCC1353,RCC1557,RCC174,RCC834,RCC950}, pages = {1{\textendash}13}, keywords = {bioaccumulation, biogeochemical cycle, metallome, phytoplankton, RCC1, RCC1242, RCC1353, RCC1557, rcc174, RCC834, RCC950, thallium}, issn = {00167037}, doi = {10.1016/j.gca.2020.02.024}, url = {https://doi.org/10.1016/j.gca.2020.02.024 https://linkinghub.elsevier.com/retrieve/pii/S0016703720301344}, author = {Zhang, Qiong and Rickaby, Rosalind E.M.} } @article {Vigor2020, title = {Isoprostanoid profiling of marine microalgae}, journal = {Biomolecules}, volume = {10}, number = {7}, year = {2020}, note = {Publisher: MDPI AG tex.mendeley-tags: RCC1349,RCC20,RCC69}, month = {jul}, pages = {1073}, abstract = {{\textexclamdown}p{\textquestiondown}Algae result from a complex evolutionary history that shapes their metabolic network. For example, these organisms can synthesize different polyunsaturated fatty acids, such as those found in land plants and oily fish. Due to the presence of numerous double-bonds, such molecules can be oxidized nonenzymatically, and this results in the biosynthesis of high-value bioactive metabolites named isoprostanoids. So far, there have been only a few studies reporting isoprostanoid productions in algae. To fill this gap, the current investigation aimed at profiling isoprostanoids by liquid chromatography -mass spectrometry/mass spectrometry (LC-MS/MS) in four marine microalgae. A good correlation was observed between the most abundant polyunsaturated fatty acids (PUFAs) produced by the investigated microalgal species and their isoprostanoid profiles. No significant variations in the content of oxidized derivatives were observed for Rhodomonas salina and Chaetoceros gracilis under copper stress, whereas increases in the production of C18-, C20- and C22-derived isoprostanoids were monitored in Tisochrysis lutea and Phaeodactylum tricornutum. In the presence of hydrogen peroxide, no significant changes were observed for C. gracilis and for T. lutea, while variations were monitored for the other two algae. This study paves the way to further studying the physiological roles of isoprostanoids in marine microalgae and exploring these organisms as bioresources for isoprostanoid production.{\textexclamdown}/p{\textquestiondown}}, keywords = {Isoprostanoids, Micro-LC-MS/MS, Microalgae, Oxidative stress, PUFAs, RCC1349, RCC20, RCC69}, issn = {2218-273X}, doi = {10.3390/biom10071073}, url = {https://www.mdpi.com/2218-273X/10/7/1073}, author = {Vigor, Claire and Oger, Camille and Reversat, Guillaume and Rocher, Amandine and Zhou, Bingqing and Linares-Maurizi, Amandyne and Guy, Alexandre and Bultel-Ponc{\'e}, Val{\'e}rie and Galano, Jean-Marie and Vercauteren, Joseph and Durand, Thierry and Potin, Philippe and Tonon, Thierry and Leblanc, Catherine} } @article {Zimmerman2019, title = {Closely related viruses of the marine picoeukaryotic alga Ostreococcus lucimarinus exhibit different ecological strategies}, journal = {Environmental Microbiology}, volume = {00}, year = {2019}, note = {tex.mendeley-tags: RCC3401,RCC393,RCC829}, abstract = {SUMMARY In marine ecosystems viruses are major disrupters of the direct flow of carbon and nutrients to higher trophic levels. While the genetic diversity of several eukaryotic phytoplankton virus groups has been characterized, their infection dynamics are less understood, such that the physiological and ecological implications of their diversity remain unclear. We compared genomes and infection phenotypes of the two most closely related cultured phycodnaviruses infecting the widespread picoprasinophyte Ostreococcus lucimarinus under standard- (1.3 divisions d-1) and limited-light (0.41 divisions d-1) nutrient replete conditions. OlV7 infection caused early arrest of the host cell cycle, coinciding with a significantly higher proportion of infected cells than OlV1-amended treatments, regardless of host growth rate. OlV7 treatments showed a near-50-fold increase of progeny virions at the higher host growth rate, contrasting with OlV1{\textquoteright}s 16-fold increase. However, production of OlV7 virions was more sensitive than OlV1 production to reduced host growth rate, suggesting fitness trade-offs between infection efficiency and resilience to host physiology. Moreover, while organic matter released from OlV1- and OlV7-infected hosts had broadly similar chemical composition, some distinct molecular signatures were observed. Collectively, these results suggest that current views on viral relatedness through marker and core gene analyses underplay operational divergence and consequences for host ecology. This article is protected by copyright. All rights reserved.}, keywords = {rcc3401, RCC393, RCC829}, issn = {14622920}, doi = {10.1111/1462-2920.14608}, author = {Zimmerman, Amy E. and Bachy, Charles and Ma, Xiufeng and Roux, Simon and Jang, Ho Bin and Sullivan, Matthew B. and Waldbauer, Jacob R. and Worden, Alexandra Z.} } @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 {Beuvier2019, title = {X-ray nanotomography of coccolithophores reveals that coccolith mass and segment number correlate with grid size}, journal = {Nature Communications}, volume = {10}, number = {1}, year = {2019}, note = {Publisher: Springer US tex.mendeley-tags: RCC1212,RCC1216,RCC1314,RCC3370,RCC4032,RCC4036}, month = {dec}, pages = {751}, abstract = {Coccolithophores of the No{\"e}laerhabdaceae family are covered by imbricated coccoliths, each composed of multiple calcite crystals radially distributed around the periphery of a grid. The factors that determine coccolith size remain obscure. Here, we used synchrotron-based three-dimensional Coherent X-ray Diffraction Imaging to study coccoliths of 7 species of Gephyrocapsa, Emiliania and Reticulofenestra with a resolution close to 30 nm. Segmentation of 45 coccoliths revealed remarkable size, mass and segment number variations, even within single coccospheres. In particular, we observed that coccolith mass correlates with grid perimeter which scales linearly with crystal number. Our results indirectly support the idea that coccolith mass is determined in the coccolith vesicle by the size of the organic base plate scale (OBPS) around which R-unit nucleation occurs every 110{\textendash}120 nm. The curvation of coccoliths allows inference of a positive correlation between cell nucleus, OBPS and coccolith sizes.}, keywords = {Biomaterials, Marine biology, rcc1212, RCC1216, RCC1314, RCC3370, RCC4032, RCC4036}, issn = {2041-1723}, doi = {10.1038/s41467-019-08635-x}, url = {http://www.nature.com/articles/s41467-019-08635-x}, author = {Beuvier, T. and Probert, I. and Beaufort, L. and Such{\'e}ras-Marx, B. and Chushkin, Y. and Zontone, F. and Gibaud, A.} } @article {McQuaid2018, title = {Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms}, journal = {Nature}, volume = {555}, number = {7697}, year = {2018}, note = {Publisher: Nature Publishing Group tex.mendeley-tags: RCC2967}, month = {mar}, pages = {534{\textendash}537}, abstract = {Iron is an essential nutrient for photosynthetic plankton (phytoplankton), but owing to its low solubility in vast areas of the ocean the concentration of this metal is low, limiting the growth of the phytoplankton. Andrew Allen and co-workers show that the phytoplankton Phaeodactylum tricornutum has developed a specific iron acquisition mechanism that relies on activity of the ISIP2A protein. ISIP2A represents a functional analogue of transferrin{\textemdash}a metazoan protein that binds iron with high affinity{\textemdash}as both proteins use similar iron binding, internalization and release mechanisms, suggesting their independent and convergent evolution. Both proteins bind iron through a synergistic interaction of ferric iron and CO32-, and because ocean acidification decreases CO32- concentration it may also decrease phytoplankton iron uptake and growth.}, keywords = {RCC2967}, issn = {0028-0836}, doi = {10.1038/nature25982}, url = {http://dx.doi.org/10.1038/nature25982 http://www.nature.com/doifinder/10.1038/nature25982}, author = {McQuaid, Jeffrey B. and Kustka, Adam B. and Obornik, Miroslav and Horak, Ales and McCrow, John P. and Karas, Bogumil J. and Zheng, Hong and Kindeberg, Theodor and Andersson, Andreas J. and Barbeau, Katherine A. and Allen, Andrew E.} } @article {Rosas-Navarro2018, title = {Temperature effects on sinking velocity of different Emiliania huxleyi strains}, journal = {PLOS ONE}, volume = {13}, number = {3}, year = {2018}, note = {ISBN: 1111111111 tex.mendeley-tags: IAN01,RCC1252,RCC1710}, pages = {e0194386}, abstract = {The sinking properties of three strains of Emiliania huxleyi in response to temperature changes were examined. We used a recently proposed approach to calculate sinking velocities from coccosphere architecture, which has the advantage to be applicable not only to culture samples, but also to field samples including fossil material. Our data show that temperature in the sub-optimal range impacts sinking velocity of E. huxleyi. This response is widespread among strains isolated in different locations and moreover comparatively predictable, as indicated by the similar slopes of the linear regressions. Sinking velocity was positively correlated to temperature as well as individual cell PIC/POC over the sub-optimum to optimum temperature range in all strains. In the context of climate change our data point to an important influence of global warming on sinking velocities. It has recently been shown that seawater acidification has no effect on sinking velocity of a Mediterranean E. huxleyi strain, while nutrient limitation seems to have a small negative effect on sinking velocity. Given that warming, acidification, and lowered nutrient availability will occur simultaneously under climate change scenarios, the question is what the net effect of different influential factors will be. For example, will the effects of warming and nutrient limitation cancel? This question cannot be answered conclusively but analyses of field samples in addition to laboratory culture studies will improve predictions because in field samples multi-factor influences and even evolutionary changes are not excluded. As mentioned above, the approach of determining sinking rate followed here is applicable to field samples. Future studies could use it to analyse not only seasonal and geographic patterns but also changes in sinking velocity over geological time scales.}, keywords = {IAN01, rcc1252, rcc1710}, issn = {1932-6203}, doi = {10.1371/journal.pone.0194386}, url = {http://dx.plos.org/10.1371/journal.pone.0194386}, author = {Rosas-Navarro, Anaid and Langer, Gerald and Ziveri, Patrizia}, editor = {Johnson, Colin} } @article {Ni2016, title = {Arctic Micromonas uses protein pools and non-photochemical quenching to cope with temperature restrictions on Photosystem II protein turnover}, journal = {Photosynthesis Research}, volume = {131}, number = {2}, year = {2017}, note = {ISBN: 1112001603 Publisher: Springer Netherlands tex.mendeley-tags: 2016,RCC806}, month = {feb}, pages = {203{\textendash}220}, keywords = {2016, {\'a}, Photoinactivation, photoinactivation {\'a} xanthophyll cycle, Photosystem II, Prasinophyte, prasinophyte {\'a} photosystem ii, RCC806, Xanthophyll cycle}, issn = {0166-8595}, doi = {10.1007/s11120-016-0310-6}, url = {http://link.springer.com/10.1007/s11120-016-0310-6}, author = {Ni, Guangyan and Zimbalatti, Gabrielle and Murphy, Cole D. and Barnett, Audrey B. and Arsenault, Christopher M. and Li, Gang and Cockshutt, Amanda M. and Campbell, Douglas A.} } @article {Leliaert2016, title = {Chloroplast phylogenomic analyses reveal the deepest-branching lineage of the Chlorophyta, Palmophyllophyceae class. nov.}, journal = {Scientific Reports}, volume = {6}, year = {2016}, note = {tex.mendeley-tags: 2016,RCC15,RCC299}, month = {may}, pages = {25367}, keywords = {2016, RCC15, RCC299}, issn = {2045-2322}, doi = {10.1038/srep25367}, url = {http://www.nature.com/articles/srep25367}, author = {Leliaert, Frederik and Tronholm, Ana and Lemieux, Claude and Turmel, Monique and DePriest, Michael S. and Bhattacharya, Debashish and Karol, Kenneth G. and Fredericq, Suzanne and Zechman, Frederick W. and Lopez-Bautista, Juan M.} } @article {Zheng2016, title = {The geographic impact on genomic divergence as revealed by comparison of nine Citromicrobial genomes}, journal = {Applied and Environmental Microbiology}, volume = {82}, number = {24}, year = {2016}, note = {tex.mendeley-tags: 2016,RCC1878,RCC1885,RCC1897,sbr?hyto?app}, pages = {AEM.02495{\textendash}16}, abstract = {Aerobic anoxygenic phototrophic bacteria (AAPB) are thought to be important players in oceanic carbon and energy cycling in the euphotic zone of the ocean. The genus Citromicrobium , widely found in oligotrophic oceans, is a member of marine alphaproteobacterial AAPB. Nine Citromicrobium strains isolated from the South China Sea, the Mediterranean Sea or the tropical South Atlantic were found to harbor identical 16S rRNA sequences. The sequencing of their genomes revealed high synteny in major regions. Nine genetic islands (GIs), involved mainly in type IV secretion systems, flagellar biosynthesis, prophage and integrative conjugative elements, were identified by a fine scale comparative genomics analysis. These GIs played significant roles in genomic evolution and divergence. Interestingly, the co-existence of two different photosynthetic gene clusters (PGCs) was not only found in the analyzed genomes but also confirmed, for the first time, in environmental samples. The prevalence of the coexistence of two different PGCs may suggest an adaptation mechanism for Citromicrobium members to survive in the oceans. Comparison of genomic characteristics (e.g., GIs, ANI, SNPs and phylogeny) revealed that strains within a marine region shared a similar evolutionary history that was distinct from that of strains isolated from other regions (South China Sea vs Mediterranean Sea). Geographic differences are partly responsible for driving the observed genomic divergences, and allow microbes to evolve through local adaptation. Three Citromicrobium strains isolated from the Mediterranean Sea diverged millions of years ago from other strains, and evolved into a novel group.}, keywords = {2016, RCC1878, RCC1885, RCC1897, sbr?hyto?app}, issn = {0099-2240}, doi = {10.1128/AEM.02495-16}, url = {http://aem.asm.org/lookup/doi/10.1128/AEM.02495-16}, author = {Zheng, Qiang and Liu, Yanting and Jeanthon, Christian and Zhang, Rui and Lin, Wenxin and Yao, Jicheng and Jiao, Nianzhi} } @article {Rosas-Navarro2016, title = {Temperature affects the morphology and calcification of Emiliania huxleyi strains}, journal = {Biogeosciences}, volume = {13}, number = {10}, year = {2016}, note = {tex.mendeley-tags: 2016,rcc1252,rcc1710}, month = {may}, pages = {2913{\textendash}2926}, abstract = {The global warming debate has sparked an unprecedented interest in temperature effects on coccolithophores. The calcification response to temperature changes reported in the literature, however, is ambiguous. The two main sources of this ambiguity are putatively differences in experimental setup and strain specificity. In this study we therefore compare three strains isolated in the North Pacific under identical experimental conditions. Three strains of Emiliania huxleyi type A were grown under non-limiting nutrient and light conditions, at 10, 15, 20 and 25 {\textdegree}C. All three strains displayed similar growth rate versus temperature relationships, with an optimum at 20{\textendash}25 {\textdegree}C. Elemental production (particulate inorganic carbon (PIC), particulate organic carbon (POC), total particulate nitrogen (TPN)), coccolith mass, coccolith size, and width of the tube element cycle were positively correlated with temperature over the sub-optimum to optimum temperature range. The correlation between PIC production and coccolith mass/size supports the notion that coccolith mass can be used as a proxy for PIC production in sediment samples. Increasing PIC production was significantly positively correlated with the percentage of incomplete coccoliths in one strain only. Generally, coccoliths were heavier when PIC production was higher. This shows that incompleteness of coccoliths is not due to time shortage at high PIC production. Sub-optimal growth temperatures lead to an increase in the percentage of malformed coccoliths in a strain-specific fashion. Since in total only six strains have been tested thus far, it is presently difficult to say whether sub-optimal temperature is an important factor causing malformations in the field. The most important parameter in biogeochemical terms, the PIC : POC ratio, shows a minimum at optimum growth temperature in all investigated strains. This clarifies the ambiguous picture featuring in the literature, i.e. discrepancies between PIC : POC{\textendash}temperature relationships reported in different studies using different strains and different experimental setups. In summary, global warming might cause a decline in coccolithophore{\textquoteright}s PIC contribution to the rain ratio, as well as improved fitness in some genotypes due to fewer coccolith malformations.}, keywords = {2016, rcc1252, rcc1710}, issn = {1726-4189}, doi = {10.5194/bg-13-2913-2016}, url = {http://www.biogeosciences.net/13/2913/2016/}, author = {Rosas-Navarro, Anaid and Langer, Gerald and Ziveri, Patrizia} } @article {Decelle2015, title = {PhytoREF: a reference database of the plastidial 16S rRNA gene of photosynthetic eukaryotes with curated taxonomy}, journal = {Molecular Ecology Resources}, volume = {15}, number = {6}, year = {2015}, note = {tex.mendeley-tags: 2015,macumba,rcc,sbr?hyto$_\textrmd$ipo,sbr?hyto?ppo}, pages = {1435{\textendash}1445}, abstract = {Photosynthetic eukaryotes have a critical role as the main producers in most ecosystems of the biosphere. The ongo- ing environmental metabarcoding revolution opens the perspective for holistic ecosystems biological studies of these organisms, in particular the unicellular microalgae that often lack distinctive morphological characters and have complex life cycles. To interpret environmental sequences, metabarcoding necessarily relies on taxonomically curated databases containing reference sequences of the targeted gene (or barcode) from identified organisms. To date, no such reference framework exists for photosynthetic eukaryotes. In this study, we built the PhytoREF data- base that contains 6490 plastidial 16S rDNA reference sequences that originate from a large diversity of eukaryotes representing all known major photosynthetic lineages. We compiled 3333 amplicon sequences available from public databases and 879 sequences extracted from plastidial genomes, and generated 411 novel sequences from cultured marine microalgal strains belonging to different eukaryotic lineages. A total of 1867 environmental Sanger 16S rDNA sequences were also included in the database. Stringent quality filtering and a phylogeny-based taxonomic classifica- tion were applied for each 16S rDNA sequence. The database mainly focuses on marine microalgae, but sequences from land plants (representing half of the PhytoREF sequences) and freshwater taxa were also included to broaden the applicability of PhytoREF to different aquatic and terrestrial habitats. PhytoREF, accessible via a web interface (http://phytoref.fr), is a new resource in molecular ecology to foster the discovery, assessment and monitoring of the diversity of photosynthetic eukaryotes using high-throughput sequencing.}, keywords = {2015, MACUMBA, rcc, RCC?o?dd, SBR$_\textrmP$hyto$_\textrmD$IPO, SBR$_\textrmP$hyto$_\textrmE$PPO, sbr?hyto$_\textrmd$ipo, sbr?hyto?ppo}, issn = {1755098X}, doi = {10.1111/1755-0998.12401}, url = {http://doi.wiley.com/10.1111/1755-0998.12401}, author = {Decelle, Johan and Romac, Sarah and Stern, Rowena F. and Bendif, El Mahdi and Zingone, Adriana and Audic, St{\'e}phane and Guiry, Michael D. and Guillou, Laure and Tessier, D{\'e}sir{\'e} and Le Gall, Florence and Gourvil, Priscillia and dos Santos, Adriana Lopes and Probert, Ian and Vaulot, Daniel and de Vargas, Colomban and Christen, Richard} } @article {Bombar2014, title = {Comparative genomics reveals surprising divergence of two closely related strains of uncultivated UCYN-A cyanobacteria}, journal = {The ISME Journal}, volume = {8}, number = {12}, year = {2014}, note = {Publisher: Nature Publishing Group tex.mendeley-tags: rcc}, pages = {2530{\textendash}2542}, keywords = {rcc}, issn = {1751-7362}, doi = {10.1038/ismej.2014.167}, url = {http://www.nature.com/doifinder/10.1038/ismej.2014.167}, author = {Bombar, Deniz and Heller, Philip and Sanchez-Baracaldo, Patricia and Carter, Brandon J and Zehr, Jonathan P} } @article {Keeling2014, title = {The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP): illuminating the functional diversity of eukaryotic life in the oceans through transcriptome sequencing}, journal = {PLoS biology}, volume = {12}, number = {6}, year = {2014}, note = {Publisher: Public Library of Science tex.mendeley-tags: 2014,rcc,sbr?hyto$_\textrmd$ipo}, pages = {e1001889}, abstract = {Current sampling of genomic sequence data from eukaryotes is relatively poor, biased, and inadequate to address important questions about their biology, evolution, and ecology; this Community Page describes a resource of 700 transcriptomes from marine microbial eukaryotes to help understand their role in the world{\textquoteright}s oceans}, keywords = {2014, rcc, SBR$_\textrmP$hyto$_\textrmD$PO, sbr?hyto$_\textrmd$ipo}, doi = {10.1371/journal.pbio.1001889}, url = {http://dx.doi.org/10.1371\%252Fjournal.pbio.1001889}, author = {Keeling, Patrick J and Burki, Fabien and Wilcox, Heather M and Allam, Bassem and Allen, Eric E and Amaral-Zettler, Linda A and Armbrust, E Virginia and Archibald, John M and Bharti, Arvind K and Bell, Callum J and Beszteri, Bank and Bidle, Kay D and Cameron, Connor T and Campbell, Lisa and Caron, David A and Cattolico, Rose Ann and Collier, Jackie L and Coyne, Kathryn and Davy, Simon K and Deschamps, Phillipe and Dyhrman, Sonya T and Edvardsen, Bente and Gates, Ruth D and Gobler, Christopher J and Greenwood, Spencer J and Guida, Stephanie M and Jacobi, Jennifer L and Jakobsen, Kjetill S and James, Erick R and Jenkins, Bethany and John, Uwe and Johnson, Matthew D and Juhl, Andrew R and Kamp, Anja and Katz, Laura A and Kiene, Ronald and Kudryavtsev, Alexander and Leander, Brian S and Lin, Senjie and Lovejoy, Connie and Lynn, Denis and Marchetti, Adrian and McManus, George and Nedelcu, Aurora M and Menden-Deuer, Susanne and Miceli, Cristina and Mock, Thomas and Montresor, Marina and Moran, Mary Ann and Murray, Shauna and Nadathur, Govind and Nagai, Satoshi and Ngam, Peter B and Palenik, Brian and Pawlowski, Jan and Petroni, Giulio and Piganeau, Gwenael and Posewitz, Matthew C and Rengefors, Karin and Romano, Giovanna and Rumpho, Mary E and Rynearson, Tatiana and Schilling, Kelly B and Schroeder, Declan C and Simpson, Alastair G B and Slamovits, Claudio H and Smith, David R and Smith, G Jason and Smith, Sarah R and Sosik, Heidi M and Stief, Peter and Theriot, Edward and Twary, Scott N and Umale, Pooja E and Vaulot, Daniel and Wawrik, Boris and Wheeler, Glen L and Wilson, William H and Xu, Yan and Zingone, Adriana and Worden, Alexandra Z} } @article {Collen2013, title = {Genome structure and metabolic features in the red seaweed Chondrus crispus shed light on evolution of the Archaeplastida}, journal = {Proceedings of the National Academy of Sciences}, volume = {110}, number = {13}, year = {2013}, note = {tex.mendeley-tags: RCC299}, pages = {5247{\textendash}5252}, abstract = {Red seaweeds are key components of coastal ecosystems and are economically important as food and as a source of gelling agents, but their genes and genomes have received little attention. Here we report the sequencing of the 105-Mbp genome of the florideophyte Chondrus crispus (Irish moss) and the annotation of the 9,606 genes. The genome features an unusual structure characterized by gene-dense regions surrounded by repeat-rich regions dominated by transposable elements. Despite its fairly large size, this genome shows features typical of compact genomes, e.g., on average only 0.3 introns per gene, short introns, low median distance between genes, small gene families, and no indication of large-scale genome duplication. The genome also gives insights into the metabolism of marine red algae and adaptations to the marine environment, including genes related to halogen metabolism, oxylipins, and multicellularity (microRNA processing and transcription factors). Particularly interesting are features related to carbohydrate metabolism, which include a minimalistic gene set for starch biosynthesis, the presence of cellulose synthases acquired before the primary endosymbiosis showing the polyphyly of cellulose synthesis in Archaeplastida, and cellulases absent in terrestrial plants as well as the occurrence of a mannosylglycerate synthase potentially originating from a marine bacterium. To explain the observations on genome structure and gene content, we propose an evolutionary scenario involving an ancestral red alga that was driven by early ecological forces to lose genes, introns, and intergenetic DNA; this loss was followed by an expansion of genome size as a consequence of activity of transposable elements.}, keywords = {RCC299}, doi = {10.1073/pnas.1221259110}, url = {http://www.pnas.org/content/110/13/5247.abstract}, author = {Collen, Jonas and Porcel, Betina and Carr{\'e}, Wilfrid and Ball, Steven G and Chaparro, Cristian and Tonon, Thierry and Barbeyron, Tristan and Michel, Gurvan and Noel, Benjamin and Valentin, Klaus and Elias, Marek and Artiguenave, Fran{\c c}ois and Arun, Alok and Aury, Jean-Marc and Barbosa-Neto, Jos{\'e} F and Bothwell, John H and Bouget, Fran{\c c}ois-Yves and Brillet, Loraine and Cabello-Hurtado, Francisco and Capella-Guti{\'e}rrez, Salvador and Charrier, B{\'e}n{\'e}dicte and Cladi{\`e}re, Lionel and Cock, J Mark and Coelho, Susana M and Colleoni, Christophe and Czjzek, Mirjam and Da Silva, Corinne and Delage, Ludovic and Denoeud, France and Deschamps, Philippe and Dittami, Simon M and Gabald{\'o}n, Toni and Gachon, Claire M M and Groisillier, Agn{\`e}s and Herv{\'e}, C{\'e}cile and Jabbari, Kamel and Katinka, Michael and Kloareg, Bernard and Kowalczyk, Nathalie and Labadie, Karine and Leblanc, Catherine and Lopez, Pascal J and McLachlan, Deirdre H and Meslet-Cladiere, Laurence and Moustafa, Ahmed and Nehr, Zofia and Nyvall Coll{\'e}n, Pi and Panaud, Olivier and Partensky, Fr{\'e}d{\'e}ric and Poulain, Julie and Rensing, Stefan A and Rousvoal, Sylvie and Samson, Gaelle and Symeonidi, Aikaterini and Weissenbach, Jean and Zambounis, Antonios and Wincker, Patrick and Boyen, Catherine} } @article {Guillou2013, title = {The protist ribosomal reference database (PR2): a catalog of unicellular eukaryote small SubUnit rRNA sequences with curated taxonomy}, journal = {Nucleic Acids Research}, volume = {41}, year = {2013}, note = {tex.mendeley-tags: 2013,rcc,sbr?hyto$_\textrmd$ipo,sbr?hyto?ppo}, pages = {D597{\textendash}D604}, keywords = {2013, rcc, SBR$_\textrmP$hyto$_\textrmD$PO, SBR$_\textrmP$hyto$_\textrmE$PPO, sbr?hyto$_\textrmd$ipo, sbr?hyto?ppo}, doi = {10.1093/nar/gks1160}, author = {Guillou, Laure and Bachar, Dipankar and Audic, St{\'e}phane and Bass, David and Berney, Cedric and Bittner, Lucie and Boutte, Christophe and Burgaud, Gaetan and de Vargas, Colomban and Decelle, Johan and del Campo, Javier and Dolan, John and Dunthorn, Micah and Bente, Edvardsen and Holzmann, Maria and Kooistra, Wiebe H C F and Lara, Enrique and Lebescot, Noan and Logares, Ramiro and Mah{\'e}, Fr{\'e}d{\'e}ric and Massana, Ramon and Montresor, Marina and Morard, Raphael and Not, Fabrice and Pawlowski, Jan and Probert, Ian and Sauvadet, Anne-Laure and Siano, Raffaele and Stoeck, Thorsten and Vaulot, Daniel and Zimmermann, Pascal and Christen, Richard} } @article {Zeng2012, title = {Marine viruses exploit their host{\textquoteright}s two-component regulatory system in response to resource limitation}, journal = {Current Biology}, year = {2012}, note = {Publisher: Cell Press tex.mendeley-tags: rcc}, abstract = {Phosphorus (P) availability, which often limits productivity in marine ecosystems, shapes the P-acquisition gene content of the marine cyanobacteria Prochlorococcus [1 4] and its viruses (cyanophages) [5, 6]. As in other bacteria, in Prochlorococcus these genes are regulated by the PhoR/PhoB two-component regulatory system that is used to sense and respond to P availability and is typical of signal transduction systems found in diverse organisms [7]. Replication of cyanophage genomes requires a significant amount of P, and therefore these phages could gain a fitness advantage by influencing host P acquisition in P-limited environments. Here we show that the transcription of a phage-encoded high-affinity phosphate-binding protein gene (pstS) and alkaline phosphatase gene (phoA) both of which have host orthologs is elevated when the phages are infecting host cells that are P starved, relative to P-replete control cells. We further show that the phage versions of these genes are regulated by the host{\textquoteright}s PhoR/PhoB system. This not only extends this fundamental signaling mechanism to viruses but is also the first example of regulation of lytic phage genes by nutrient limitation in the host. As such, it reveals an important new dimension of the intimate coevolution of phage, host, and environment in the world{\textquoteright}s oceans. {\textordmasculine} Phage production, but not lytic cycle, is reduced in P-starved host cells {\textordmasculine} Transcription of phage P acquisition genes is upregulated in P-starved hosts {\textordmasculine} Phage P-acquisition genes are regulated by the host PhoR/PhoB two-component system {\textordmasculine} This is the first incidence of regulation of virus genes by a two-component system}, keywords = {NATL2A, rcc, RCC?o?dd}, doi = {10.1016/j.cub.2011.11.055}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0960982211013704}, author = {Zeng, Qinglu and Chisholm, Sallie W} } @article {Thompson2012, title = {Unicellular cyanobacterium symbiotic with a single-celled eukaryotic alga}, journal = {Science}, volume = {337}, number = {6101}, year = {2012}, note = {tex.mendeley-tags: 2012,microb3,rcc,sbr?hyto$_\textrmd$ipo}, pages = {1546{\textendash}1550}, abstract = {Symbioses between nitrogen (N)2{\textendash}fixing prokaryotes and photosynthetic eukaryotes are important for nitrogen acquisition in N-limited environments. Recently, a widely distributed planktonic uncultured nitrogen-fixing cyanobacterium (UCYN-A) was found to have unprecedented genome reduction, including the lack of oxygen-evolving photosystem II and the tricarboxylic acid cycle, which suggested partnership in a symbiosis. We showed that UCYN-A has a symbiotic association with a unicellular prymnesiophyte, closely related to calcifying taxa present in the fossil record. The partnership is mutualistic, because the prymnesiophyte receives fixed N in exchange for transferring fixed carbon to UCYN-A. This unusual partnership between a cyanobacterium and a unicellular alga is a model for symbiosis and is analogous to plastid and organismal evolution, and if calcifying, may have important implications for past and present oceanic N2 fixation.}, keywords = {2012, MicroB3, rcc, SBR$_\textrmP$hyto$_\textrmD$PO, sbr?hyto$_\textrmd$ipo}, doi = {10.1126/science.1222700}, url = {http://www.sciencemag.org/content/337/6101/1546.abstract}, author = {Thompson, Anne W and Foster, Rachel A and Krupke, Andreas and Carter, Brandon J and Musat, Niculina and Vaulot, Daniel and Kuypers, Marcel M M and Zehr, Jonathan P} } @article {Kirkham2011, title = {Basin-scale distribution patterns of photosynthetic picoeukaryotes along an Atlantic Meridional Transect}, journal = {Environmental Microbiology}, volume = {13}, number = {4}, year = {2011}, note = {Publisher: Blackwell Publishing Ltd tex.mendeley-tags: Micromonas,RCC,rcc}, pages = {975{\textendash}990}, abstract = {Summary Photosynthetic picoeukaryotes (PPEs) of a size {\textexclamdown} 3 {\textmu}m play a crucial role in oceanic primary production. However, little is known of the structure of the PPE community over large spatial scales. Here, we investigated the distribution of various PPE classes along an Atlantic Meridional Transect sampled in boreal autumn 2004 that encompasses a range of ocean provinces (gyres, upwelling, temperate regions), using dot blot hybridization technology targeting plastid 16S rRNA gene amplicons. Two algal classes, Prymnesiophyceae and Chrysophyceae, dominated the PPE community throughout the Atlantic Ocean, over a range of water masses presenting different trophic profiles. However, these classes showed strongly complementary distributions with Chrysophyceae dominating northern temperate waters, the southern gyre and equatorial regions, while prymnesiophytes dominated the northern gyre. Phylogenetic analyses using both plastid and nuclear rRNA genes revealed a high diversity among members of both classes, including sequences contained in lineages with no close cultured counterpart. Other PPE classes were less prevalent along the transect, with members of the Cryptophyceae, Pelagophyceae and Eustigmatophyceae essentially restricted to specific regions. Multivariate statistical analyses revealed strong relationships between the distribution patterns of some of these latter PPE classes and temperature, light intensity and nutrient concentrations. Cryptophyceae, for example, were mostly found in the upwelling region and associated with higher nutrient concentrations. However, the key classes of Prymnesiophyceae and Chrysophyceae were not strongly influenced by the variables measured. Although there appeared to be a positive relationship between Chrysophyceae distribution and light intensity, the complementary distributions of these classes could not be explained by the variables recorded and this requires further explanation.}, keywords = {Micromonas, rcc}, doi = {10.1111/j.1462-2920.2010.02403.x}, url = {http://dx.doi.org/10.1111/j.1462-2920.2010.02403.x}, author = {Kirkham, Amy R and Jardillier, Ludwig E and Tiganescu, Ana and Pearman, John and Zubkov, Mikhail V and Scanlan, David J} } @article {Demir-Hilton2011, title = {Global distribution patterns of distinct clades of the photosynthetic picoeukaryote Ostreococcus}, journal = {The ISME journal}, volume = {5}, year = {2011}, note = {Publisher: International Society for Microbial Ecology tex.mendeley-tags: RCC745}, pages = {1095{\textendash}1107}, keywords = {rcc, RCC745}, doi = {10.1038/ismej.2010.209}, url = {http://dx.doi.org/10.1038/ismej.2010.209 http://www.nature.com/ismej/journal/vaop/ncurrent/suppinfo/ismej2010209s1.html http://www.nature.com/ismej/journal/v5/n7/full/ismej2010209a.html}, author = {Demir-Hilton, Elif and Sudek, Sebastian and Cuvelier, Marie L and Gentemann, Chelle L and Zehr, Jonathan P and Worden, Alexandra Z} } @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 {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 {Worden2009, title = {Green evolution and dynamic adaptations revealed by genomes of the marine picoeukaryotes Micromonas}, journal = {Science}, volume = {324}, year = {2009}, note = {tex.mendeley-tags: RCC299,RCC827}, pages = {268{\textendash}272}, abstract = {The photosynthetic picoeukaryote Micromonas thrives from tropical to polar marine ecosystems and belongs to an anciently diverged sister clade to land plants. We sequenced genomes from two Micromonas isolates (22 Mb, CCMP1545; 21 Mb, RCC299) and the results improve understanding of their ecology and green-lineage evolution. Despite high 18S rDNA sequence identity, only 90\% of their predicted genes were shared. Novel intronic repeat elements in CCMP1545, otherwise found only in metagenomic data, and unique riboswitch arrangements emphasized their independent evolutionary paths. Phylogenomic profiles revealed putative ancestral features, but also indicated selection/acquisition processes are actively shaping a {\textquoteleft}unique{\textquoteright} gene pool in each differently than {\textquoteleft}core{\textquoteright} genes. Current climate-change trajectories are predicted to produce conditions favoring picophytoplankton, making Micromonas potential indicators of biological change in ocean ecosystems.}, keywords = {rcc, RCC299, RCC827, SBR$_\textrmP$hyto$_\textrmD$PO, SBR$_\textrmP$hyto$_\textrmE$PPO}, doi = {10.1126/science.1167222}, author = {Worden, A Z and Lee, J.- H and Mock, T and Rouz{\'e}, P and Simmons, M P and Aerts, A L and Allen, A E and Cuvelier, M L and Derelle, E and Everett, M V and Foulon, E and Grimwood, J and Gundlach, H and Henrissat, B and Napoli, C and McDonald, S M and Parker, M S and Rombauts, S and Salamov, A and Von Dassow, P and Badger, J H and Coutinho, P M and Demir, E and Dubchak, I and Gentemann, C and Eikrem, W and Gready, J E and John, U and Lanier, W and Lindquist, E A and Lucas, S and Mayer, K F X and Moreau, H and Not, F and Otillar, R and Panaud, O and Pangilinan, J and Paulsen, I and Piegu, B and Poliakov, A and Robbens, S and Schmutz, J and Toulza, E and Wyss, T and Zelensky, A and Zhou, K and Armbrust, E V and Bhattacharya, D and Goodenough, U W and Van de Peer, Y and Grigoriev, I V} } @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 {Lobanov2007, title = {Evolutionary dynamics of eukaryotic selenoproteomes: large selenoproteomes may associate with aquatic life and small with terrestrial life}, journal = {Genome Biology}, volume = {8}, number = {9}, year = {2007}, note = {tex.mendeley-tags: RCC,rcc}, pages = {R198}, abstract = {BACKGROUND: Selenocysteine (Sec) is a selenium-containing amino acid that is co-translationally inserted into nascent polypeptides by recoding UGA codons. Selenoproteins occur in both eukaryotes and prokaryotes, but the selenoprotein content of organisms (selenoproteome) is highly variable and some organisms do not utilize Sec at all. RESULTS: We analyzed the selenoproteomes of several model eukaryotes and detected 26 and 29 selenoprotein genes in the green algae Ostreococcus tauri and Ostreococcus lucimarinus, respectively, five in the social amoebae Dictyostelium discoideum, three in the fly Drosophila pseudoobscura, and 16 in the diatom Thalassiosira pseudonana, including several new selenoproteins. Distinct selenoprotein patterns were verified by metabolic labeling of O. tauri and D. discoideum with 75Se. More than half of the selenoprotein families were shared by unicellular eukaryotes and mammals, consistent with their ancient origin. Further analyses identified massive, independent selenoprotein losses in land plants, fungi, nematodes, insects and some protists. Comparative analyses of selenoprotein-rich and -deficient organisms revealed that aquatic organisms generally have large selenoproteomes, whereas several groups of terrestrial organisms reduced their selenoproteomes through loss of selenoprotein genes and replacement of Sec with cysteine. CONCLUSION: Our data suggest many selenoproteins originated at the base of the eukaryotic domain and show that the environment plays an important role in selenoproteome evolution. In particular, aquatic organisms apparently retained and sometimes expanded their selenoproteomes, whereas the selenoproteomes of some terrestrial organisms were reduced or completely lost. These findings suggest a hypothesis that, with the exception of vertebrates, aquatic life supports selenium utilization, whereas terrestrial habitats lead to reduced use of this trace element due to an unknown environmental factor.}, keywords = {rcc}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve\&db=PubMed\&dopt=Citation\&list_uids=17880704}, author = {Lobanov, A V and Fomenko, D E and Zhang, Y and Sengupta, A and Hatfield, D L and Gladyshev, V N} } @article {Kettler2007, title = {Patterns and implications of gene gain and loss in the evolution of Prochlorococcus}, journal = {PLoS genetics}, volume = {3}, year = {2007}, note = {tex.mendeley-tags: RCC,rcc}, pages = {e231}, keywords = {rcc}, doi = {10.1371/journal.pgen.0030231}, author = {Kettler, G and Martiny, A C and Huang, K and Zucker, J and Coleman, M L and Rodrigue, S and Chen, F and Lapidus, A and Ferriera, S and Johnson, J and Steglich, C and Church, G and Richardson, P and Chisholm, S W} } @article {Medlin2007, title = {A taxonomic review of the genus Phaeocystis}, journal = {Biogeochemistry}, volume = {83}, number = {1-3}, year = {2007}, note = {ISBN: 0085-4417 tex.mendeley-tags: rcc3541}, pages = {3{\textendash}18}, abstract = {Phaeocystis is recognized both as a nuisance and as an ecologicallyphytoplankton species. Its polymorphic life cycle with bothand flagellated cells causes many taxonomic problems. Sequenceamong 22 isolates representing a global distribution of thehas been compared using three molecular markers. The-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) spacer is tooto resolve species. The most conserved 18S ribosomalacid (rDNA) analysis suggests that an undescribedPhaeocystis sp. (isolate PLY559) is a sister taxon to theunicellular Phaeocystis jahnii; this clade branched priorthe divergence of all other Phaeocystis species, including theones. The internal transcribed spacer (ITS) region showsvariation that some spatial population structure can be, at least in P. antarctica. P. globosa and P. pouchetii havedifferent ITS copies, suggestive of cryptic species that areable to hybridize. A molecular clock has been constructed thatthe divergence of the cold water colonial forms from the-water colonial forms to be about 30 Ma and the divergence of P.and P. pouchetii to be about 15 Ma. A short description ofcolonial stage and the flagellated stage for each formallyspecies is provided. Morphological information is alsoon a number of undescribed species. These include the strain559, consisting of non-colonial cells with peculiar tubular, a second non-colonial species from the north westernSea producing a lot of mucus, and a colonial species with-less flagellates found in Italian waters. In addition, threemorphotypes with scales different from those of P.were reported in the literature from Antarctic waters. Theemerging from both molecular and morphological data is that theof species in the genus is still underestimated and that crypticpseudocryptic diversity requires a sound assessment in futureof this genus. Based on all published observations, an emendedof the genus is provided.}, keywords = {Molecular clock, P. cordata, P. globosa, P. jahnii, P. pouchetii, P. scrobiculata, Phaeocystis antarctica, rcc3541, rDNA analysis}, issn = {01682563}, doi = {10.1007/s10533-007-9087-1}, author = {Medlin, Linda and Zingone, Adriana} } @article {Palenik2007, title = {The tiny eukaryote \textit{Ostreococcus provides genomic insights into the paradox of plankton speciation}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {104}, number = {18}, year = {2007}, note = {tex.mendeley-tags: RCC,rcc}, pages = {7705{\textendash}7710}, abstract = {The smallest known eukaryotes, at approximately 1-mum diameter, are Ostreococcus tauri and related species of marine phytoplankton. The genome of Ostreococcus lucimarinus has been completed and compared with that of O. tauri. This comparison reveals surprising differences across orthologous chromosomes in the two species from highly syntenic chromosomes in most cases to chromosomes with almost no similarity. Species divergence in these phytoplankton is occurring through multiple mechanisms acting differently on different chromosomes and likely including acquisition of new genes through horizontal gene transfer. We speculate that this latter process may be involved in altering the cell-surface characteristics of each species. In addition, the genome of O. lucimarinus provides insights into the unique metal metabolism of these organisms, which are predicted to have a large number of selenocysteine-containing proteins. Selenoenzymes are more catalytically active than similar enzymes lacking selenium, and thus the cell may require less of that protein. As reported here, selenoenzymes, novel fusion proteins, and loss of some major protein families including ones associated with chromatin are likely important adaptations for achieving a small cell size.}, keywords = {rcc}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve\&db=PubMed\&dopt=Citation\&list_uids=17460045}, author = {Palenik, B and Grimwood, J and Aerts, A and Rouz{\'e}, P and Salamov, A and Putnam, N and Dupont, C and Jorgensen, R and Derelle, E and Rombauts, S and Zhou, K and Otillar, R and Merchant, S S and Podell, S and Gaasterland, T and Napoli, C and Gendler, K and Manuell, A and Tai, V and Vallon, O and Piganeau, G and Jancek, S and Heijde, M and Jabbari, K and Bowler, C and Lohr, M and Robbens, S and Werner, G and Dubchak, I and Pazour, G J and Ren, Q and Paulsen, I and Delwiche, C and Schmutz, J and Rokhsar, D and Van de Peer, Y and Moreau, H and Grigoriev, I V} } @article {Zhu2005, title = {Mapping of picoeucaryotes in marine ecosystems with quantitative PCR of the 18S rRNA gene}, journal = {FEMS Microbiology Ecology}, volume = {52}, number = {1}, year = {2005}, note = {tex.mendeley-tags: Micromonas,RCC,rcc}, pages = {79{\textendash}92}, abstract = {A quantitative PCR (QPCR) assay based on the use of SYBR Green I was developed to assess the abundance of specific groups of picoeukaryotes in marine waters. Six primer sets were designed targeting four different taxonomic levels: domain (Eukaryota), division (Chlorophyta), order (Mamiellales) and genus (Bathycoccus, Micromonas, and Ostreococcus). Reaction conditions were optimized for each primer set which was validated in silico, on agarose gels, and by QPCR against a variety of target and non-target cultures. The approach was tested by estimating gene copy numbers for Micromonas, Bathycoccus, and Ostreococcus in seawater samples to which cultured cells were added in various concentrations. QPCR was then used to determine that rRNA gene (rDNA) copy number varied from one to more than 12,000 in 18 strains of phytoplankton. Finally, QPCR was applied to environmental samples from a Mediterranean Sea coastal site and the results were compared to those obtained by Fluorescent in situ hybridization (FISH). The data obtained demonstrate that Chlorophyta and more specifically Mamiellales were important in these waters, especially during the winter picoplankton bloom. The timing of major abundance peaks of the targeted species was similar by QPCR and FISH. When used in conjunction with other techniques such as FISH or gene clone libraries, QPCR appears as very promising to quickly obtain data on the ecological distribution of important phytoplankton groups. Data interpretation must take into account primer specificity and the varying rRNA gene copy number among eukaryotes. ?? 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.}, keywords = {Coastal ecosystems, Ecology, Fluorescent in situ hybridization, Micromonas, picoplankton, prasinophytes, Quantitative PCR, rcc}, author = {Zhu, Fei and Massana, Ramon and Not, Fabrice and Marie, Dominique and Vaulot, Daniel} } @article {Six2005, title = {Two novel phycoerythrin-associated linker proteins in the marine cyanobacterium synechococcus sp. Strain WH8102}, journal = {Journal of Bacteriology}, volume = {187}, number = {5}, year = {2005}, note = {tex.mendeley-tags: 2005,rcc,sbr?hyto}, pages = {1685{\textendash}1694}, abstract = {The recent availability of the whole genome of Synechococcus sp. strain WH8102 allows us to have a global view of the complex structure of the phycobilisomes of this marine picocyanobacterium. Genomic analyses revealed several new characteristics of these phycobilisomes, consisting of an allophycocyanin core and rods made of one type of phycocyanin and two types of phycoerythrins (I and II). Although the allophycocyanin appears to be similar to that found commonly in freshwater cyanobacteria, the phycocyanin is simpler since it possesses only one complete set of alpha and beta subunits and two rod-core linkers (CpcG1 and CpcG2). It is therefore probably made of a single hexameric disk per rod. In contrast, we have found two novel putative phycoerythrin-associated linker polypeptides that appear to be specific for marine Synechococcus spp. The first one (SYNW2000) is unusually long (548 residues) and apparently results from the fusion of a paralog of MpeC, a phycoerythrin II linker, and of CpeD, a phycoerythrin-I linker. The second one (SYNW1989) has a more classical size (300 residues) and is also an MpeC paralog. A biochemical analysis revealed that, like MpeC, these two novel linkers were both chromophorylated with phycourobilin. Our data suggest that they are both associated (partly or totally) with phycoerythrin II, and we propose to name SYNW2000 and SYNW1989 MpeD and MpeE, respectively. We further show that acclimation of phycobilisomes to high light leads to a dramatic reduction of MpeC, whereas the two novel linkers are not significantly affected. Models for the organization of the rods are proposed.}, keywords = {2005, rcc, SBR$_\textrmP$hyto, sbr?hyto}, doi = {10.1128/JB.187.5.1685-1694.2005}, url = {http://jb.asm.org/cgi/content/abstract/187/5/1685}, author = {Six, Christophe and Thomas, Jean-Claude and Thion, Laurent and Lemoine, Yves and Zal, Frank and Partensky, Fr{\'e}d{\'e}ric} } @article {Chisholm1992, title = {\textit{Prochlorococcus marinus nov. gen. nov. sp.: an oxyphototrophic marine prokaryote containing divinyl chlorophyll a and b}, journal = {Archives of Microbiology}, volume = {157}, year = {1992}, note = {tex.mendeley-tags: RCC,rcc}, pages = {297{\textendash}300}, keywords = {rcc, systematics, \#PROCHLOROPHYTE}, doi = {10.1007/BF00245165}, author = {Chisholm, S W and Frankel, S L and Goericke, R and Olson, R J and Palenik, B and Waterbury, J B and West-Johnsrud, L and Zettler, E R} }