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1. Local scale extreme low pH conditions and genetic differences shape phenotypic variation in a broad dispersal copepod species

Author

Victor M. Aguilera, Fabiola Sepulveda, Peter von Dassow, Juan Diego Gaitán-Espitia, Andrés Mesas, and Cristian A. Vargas

Subjects
coastal variability, carbon chemistry, extreme events, temperate and subtropical systems, gene flow, phenotypic plasticity, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

Extreme low pH events in estuaries and upwelling areas can modulate the phenotypic and genetic diversity of natural populations. To test this hypothesis, we explored the linkage between local scale extreme low pH events, genetic diversity, and variation in fecundity-related traits (body size, egg size, and egg production rate) in the broad-dispersal copepod Acartia tonsa. We assessed genetic and phenotypic characteristics of populations by contrasting extreme low pH environments (upwelling and temperate estuary) in the coastal Southeast Pacific, under natural and experimental conditions. These populations showed significant genetic differentiation with higher diversity in mitochondrial and nuclear loci (encoding mtCOI and 18S rRNA) in the estuarine population. Copepods from this population are exposed to more frequent extreme low pH events (< 7.7), and the adult females exhibit consistent phenotypic variation in body size, egg size, and egg production rate across different cohorts. Experimental acclimation to extreme low pH conditions revealed no significant differences in fecundity-related traits between A. tonsa populations. Although these results partially support our hypothesis, the experimental findings suggest other drivers might also influence phenotypic differences in the local environments.

Published
2023
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2. Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific

Author

Montserrat Aldunate, Peter von Dassow, Cristian A. Vargas, and Osvaldo Ulloa

Subjects
autotrophy, secondary chlorophyll maximum, oxygen minimum zones, anoxia, Prochlorococcus, heterotrophy, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

Anoxic marine zones (AMZs) constitute pelagic systems distinguished from the oxygen minimum zones (OMZs) by the complete absence of detectable oxygen and the accumulation of nitrite in mid-waters. At the top of the oxygen-depleted layer and below the oxycline, nutrients are abundant; light intensity is very much reduced (

Published
2022
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3. Do Differences in Latitudinal Distributions of Species and Organelle Haplotypes Reflect Thermal Reaction Norms Within the Emiliania/Gephyrocapsa Complex?

Author

Peter von Dassow, Paula Valentina Muñoz Farías, Sarah Pinon, Esther Velasco-Senovilla, and Simon Anguita-Salinas

Subjects
Emiliania huxleyi, Gephyrocapsa, phytoplankton, thermal reaction norms, thermal performance curves, haplogroup, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

The cosmopolitan phytoplankter Emiliania huxleyi contrasts with its closest relatives that are restricted to narrower latitudinal bands, making it interesting for exploring how alternative outcomes in phytoplankton range distributions arise. Mitochondrial and chloroplast haplogroups within E. huxleyi are shared with their closest relatives: Some E. huxleyi share organelle haplogroups with Gephyrocapsa parvula and G. ericsonii which inhabit lower latitudes, while other E. huxleyi share organelle haplogroups with G. muellerae, which inhabit high latitudes. We investigated whether the phylogeny of E. huxleyi organelles reflects environmental gradients, focusing on the Southeast Pacific where the different haplogroups and species co-occur. There was a high congruence between mitochondrial and chloroplast haplogroups within E. huxleyi. Haplogroup II of E. huxleyi is negatively associated with cooler less saline waters, compared to haplogroup I, both when analyzed globally and across temporal variability at the small special scale of a center of coastal upwelling at 30° S. A new mitochondrial haplogroup Ib detected in coastal Chile was associated with warmer waters. In an experiment focused on inter-species comparisons, laboratory-determined thermal reaction norms were consistent with latitudinal/thermal distributions of species, with G. oceanica exhibiting warm thermal optima and tolerance and G. muellerae exhibiting cooler thermal optima and tolerances. Emiliania huxleyi haplogroups I and II tended to exhibit a wider thermal niche compared to the other Gephyrocapsa, but no differences among haplogroups within E. huxleyi were found. A second experiment, controlling for local adaptation and time in culture, found a significant difference between E. huxleyi haplogroups. The difference between I and II was of the expected sign, but not the difference between I and Ib. The differences were small (≤1°C) compared to differences reported previously within E. huxleyi by local adaptation and even in-culture evolution. Haplogroup Ib showed a narrower thermal niche. The cosmopolitanism of E. huxleyi might result from both wide-spread generalist phenotypes and specialist phenotypes, as well as a capacity for local adaptation. Thermal reaction norm differences can well explain the species distributions but poorly explain distributions among mitochondrial haplogroups within E. huxleyi. Perhaps organelle haplogroup distributions reflect historical rather than selective processes.

Published
2021
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4. Size-Fractionated Contribution of Microbial Biomass to Suspended Organic Matter in the Eastern Tropical South Pacific Oxygen Minimum Zone

Author

Sebastian I. Cantarero, Carlos Henríquez-Castillo, Nadia Dildar, Cristian A. Vargas, Peter von Dassow, Marcela Cornejo-D’Ottone, and Julio Sepúlveda

Subjects
intact polar lipids, oxygen minimum zone, marine biogeochemistry, biomarker, microbial biomass, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

Cell membrane intact polar lipids (IPLs) are chemotaxonomic biomarkers whose abundances and distributions in water column environments reflect the living biomass of in situ microbial communities, and can be used to determine the relative contribution of distinct functional and phylogenetic groups to water column carbon stocks. The diversity of IPLs in marine environments is, however, vast, while our knowledge of their biological origins remains limited. Here, we study the distribution of IPLs in size-fractionated suspended organic matter from the oxygen minimum zone (OMZ) of the eastern tropical South Pacific (ETSP) off northern Chile. Canonical correspondence analyses of total IPL abundances and water column physiochemistry demonstrate distinct distributions of microbial sources associated with different geochemical regions in the water column (chlorophyll maximum, upper chemocline, lower chemocline, upper OMZ, core OMZ, and mesopelagic region). Furthermore, the distribution of IPLs in free-living (0.3–2.7 μm) and particle-attached (2.7–53 μm) suspended organic matter differs, suggesting distinct biological sources in each size fraction. While some parallels exist, the diversity and distribution of IPLs in the OMZ system of the ETSP off northern Chile exhibited some unique features compared to other OMZ systems; for instance, we observed a significantly lower contribution of betaine lipids from phytoplanktonic sources, possibly reflecting a physiological response to severe N-limitation in this area. The overall IPL abundance in the two size fractions also indicates a dominance of free-living biomass in the OMZ and mesopelagic regions, suggesting that these areas of the water column could provide additional sources of submicrometer-sized organic carbon to deeper waters. This study improves the utility of IPLs as chemotaxonomic biomarkers by providing insight into the contrasting distributions of microbial biomass from different life modes (free-living and particle-attached). Our results suggest that microbial production in low oxygen environments may be more important to total water column carbon stocks than previously thought.

Published
2020
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5. Response of Phytoplankton Assemblages From Naturally Acidic Coastal Ecosystems to Elevated pCO2

Author

Natalia Osma, Laura Latorre-Melín, Bárbara Jacob, Paulina Y. Contreras, Peter von Dassow, and Cristian A. Vargas

Subjects
climate change, environmental variability, carbonate chemistry, community structure, coastal upwelling, estuary, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

The interplay of coastal oceanographic processes usually results in partial pressures of CO2 (pCO2) higher than expected from the equilibrium with the atmosphere and even higher than those expected by the end of the century. Although this is a well-known situation, the natural variability of seawater chemistry at the locations from which tested organisms or communities originate is seldom considered in ocean acidification experiments. In this work, we aimed to evaluate the role of the carbonate chemistry dynamics in shaping the response of coastal phytoplankton communities to increased pCO2 levels. The study was conducted at two coastal ecosystems off Chile, the Valdivia River estuary and the coastal upwelling ecosystem in the Arauco Gulf. We characterized the seasonal variability (winter/summer) of the hydrographic conditions, the carbonate system parameters, and the phytoplankton community structure at both sites. The results showed that carbonate chemistry dynamics in the estuary were mainly related to seasonal changes in freshwater discharges, with acidic and corrosive conditions dominating in winter. In the Arauco Gulf, these conditions were observed in summer, mainly associated with the upwelling of cold and high pCO2 (>1,000 μatm) waters. Diatoms dominated the phytoplankton communities at both sites, yet the one in Valdivia was more diverse. Only certain phytoplankton groups in this latter ecosystem showed a significant correlations with the carbonate system parameters. When the impact of elevated pCO2 levels was investigated by pCO2 manipulation experiments, we did not observe any significant effect on the biomass of either of the two communities. Changes in the phytoplankton species composition and abundance during the incubations were related to other factors, such as competition and growth phases. Our findings highlight the importance of the natural variability of coastal ecosystems and the potential for local adaptation in determining responses of coastal phytoplankton communities to increased pCO2 levels.

Published
2020
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6. Do phytoplankton require oxygen to survive? A hypothesis and model synthesis from oxygen minimum zones

Author

Jane C. Y. Wong, John A. Raven, Montserrat Aldunate, Sebastián Silva, Juan Diego Gaitán‐Espitia, Cristian A. Vargas, Osvaldo Ulloa, and Peter von Dassow

Subjects
Aquatic Science, Oceanography
Abstract

It is commonly known that phytoplankton have a pivotal role in marine biogeochemistry and ecosystems as carbon fixers and oxygen producers, but their response to deoxygenation has scarcely been studied. Nonetheless, in the major oceanic oxygen minimum zones (OMZs), all surface phytoplankton groups, regardless of size, disappear and are replaced by unique cyanobacteria lineages below the oxycline. To develop reasonable hypotheses to explain this pattern, we conduct a review of available information on OMZ phytoplankton, and we re-analyze previously published data (flow cytometric and hydrographic) on vertical structure of phytoplankton communities in relation to light and O-2 levels. We also review the physical constraints on O-2 acquisition as well as O-2-dependent metabolisms in phototrophs. These considerations, along with estimates of the photosynthetic capacity of phytoplankton along OMZ depth profiles using published data, suggest that top-down grazing, respiratory demand, and irradiance are insufficient to fully explain the vertical structure observed in the upper, more sunlit portions of OMZs. Photorespiration and water-water cycles are O-2-dependent pathways with low O-2 affinities. Although their metabolic roles are still poorly understood, a hypothetical dependence on such pathways by the phytoplankton adapted to the oxic ocean might explain vertical patterns in OMZs and results of laboratory experiments. This can be represented in a simple model in which the requirement for photorespiration in surface phytoplankton and O-2-inhibition of OMZ lineages reproduces the observed vertical fluorescence profiles and the replacement of phytoplankton adapted to O-2 by lineages restricted to the most O-2-deficient waters. A high O-2 requirement by modern phytoplankton would suggest a positive feedback that intensifies trends in OMZ extent and ocean oxygenation or deoxygenation, both in Earth's past and in response to current climate change.

Published
2023

7. Strength in numbers: Collaborative science for new experimental model systems.

Author

Ross F Waller, Phillip A Cleves, Maria Rubio-Brotons, April Woods, Sara J Bender, Virginia Edgcomb, Eric R Gann, Adam C Jones, Leonid Teytelman, Peter von Dassow, Steven W Wilhelm, and Jackie L Collier

Subjects
Biology (General), QH301-705.5
Abstract

Our current understanding of biology is heavily based on a small number of genetically tractable model organisms. Most eukaryotic phyla lack such experimental models, and this limits our ability to explore the molecular mechanisms that ultimately define their biology, ecology, and diversity. In particular, marine protists suffer from a paucity of model organisms despite playing critical roles in global nutrient cycles, food webs, and climate. To address this deficit, an initiative was launched in 2015 to foster the development of ecologically and taxonomically diverse marine protist genetic models. The development of new models faces many barriers, some technical and others institutional, and this often discourages the risky, long-term effort that may be required. To lower these barriers and tackle the complexity of this effort, a highly collaborative community-based approach was taken. Herein, we describe this approach, the advances achieved, and the lessons learned by participants in this novel community-based model for research.

Published
2018
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8. Biological oceanography, biogeochemical cycles, and pelagic ecosystem functioning of the east-central South Pacific Gyre: focus on Easter Island and Salas y Gómez Island

Author

Peter von Dassow and Silvana Collado-Fabbri

Subjects
Isla de Pascua, Isla Salas y Gómez, oceanografía, comunidad planctónica, función biogeoquímica, ecosistema pelágico, Aquaculture. Fisheries. Angling, SH1-691, Oceanography, GC1-1581, Biology (General), QH301-705.5
Abstract

The Exclusive Economic Zone of Chile defined by Easter Island and Salas y Gómez Island is in the South Pacific Sub-tropical Gyre (SPSG), putting it at the center of the most oligotrophic and biomass poor waters in the world. Only 10 biological oceanographic expeditions have entered this zone in 105 years (19052010). We review key aspects of the plankton ecosystem and biogeochemical function relevant for the understanding of and conservation planning for marine environments. Plankton production is limited by lack of dissolved inorganic fixed nitrogen, not phosphorous. Higher organic nitrogen levels might be biologically unavailable. Short-term experiments suggested iron is not limiting, yet iron still likely limits nitrogen fixation, and thus production, at longer time scales, as the presence of nitrogen-fixers is exceptionally low compared to other ocean gyres. Plankton function is dominated by the smallest unicellular organisms, picoplankton (

Published
2014
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9. Correction to: Identification of the meiotic toolkit in diatoms and exploration of meiosis-specific SPO11 and RAD51 homologs in the sexual species Pseudo-nitzschia multistriata and Seminavis robusta

Author

Shrikant Patil, Sara Moeys, Peter von Dassow, Marie J. J. Huysman, Daniel Mapleson, Lieven De Veylder, Remo Sanges, Wim Vyverman, Marina Montresor, and Maria Immacolata Ferrante

Subjects
Biotechnology, TP248.13-248.65, Genetics, QH426-470
Abstract

Following the publication of this article [1], the authors reported that the link to Additional file 11 linked to the wrong set of data. The correct supplementary data is provided in this Correction article (Additional file 11).

Published
2019
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10. Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific

Author

Osvaldo Ulloa, Cristian A. Vargas, Peter Von Dassow, and Montserrat Aldunate

Subjects
Global and Planetary Change, Ocean Engineering, Aquatic Science, Oceanography, Water Science and Technology
Abstract

Anoxic marine zones (AMZs) constitute pelagic systems distinguished from the oxygen minimum zones (OMZs) by the complete absence of detectable oxygen and the accumulation of nitrite in mid-waters. At the top of the oxygen-depleted layer and below the oxycline, nutrients are abundant; light intensity is very much reduced (13CPOC in the top of the oxygen-depleted layer. This data showed significant differences among stations with and without the development of a SCM, being 3.0‰ heavier when a SCM is developed, and indicating photosynthetic activity and/or remineralization in the top of the AMZ. More depleted δ13CPOC values were also found when no SCM was present indicating stronger chemoautotrophic activity, potentially driven by anammox and sulfur-oxidizing bacteria activity. Assimilation rate data show that when sufficient light and Prochlorococcus are present, photosynthesis exceeds chemoautotrophic carbon fixation, and can exceed heterotrophic assimilation of glucose or acetate. However, in the majority of the stations, assimilation rates of both glucose and acetate exceeded carbon fixation rates under light stimulation, suggesting that often the SCM is still a net heterotrophic system.

Published
2022
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11. Alteration of sexual reproduction and genetic diversity in the kelp species Laminaria digitata at the southern limit of its range.

Author

Luz Valeria Oppliger, Peter von Dassow, Sarah Bouchemousse, Marine Robuchon, Myriam Valero, Juan A Correa, Stéphane Mauger, and Christophe Destombe

Subjects
Medicine, Science
Abstract

Adaptation to marginal habitats at species range-limits has often been associated with parthenogenetic reproduction in terrestrial animals and plants. Laboratory observations have shown that brown algae exhibit a high propensity for parthenogenesis by various mechanisms. The kelp Laminaria digitata is an important component of the ecosystem in Northern European rocky intertidal habitats. We studied four L. digitata populations for the effects of marginality on genetic diversity and sexual reproduction. Two populations were marginal: One (Locquirec, in Northern Brittany) was well within the geographic range, but was genetically isolated from other populations by large stretches of sandy beaches. Another population was at the range limits of the species (Quiberon, in Southern Brittany) and was exposed to much higher seasonal temperature changes. Microsatellite analyses confirmed that these populations showed decreased genetic and allelic diversity, consistent with marginality and genetic isolation. Sporophytes from both marginal populations showed greatly diminished spore-production compared to central populations, but only the southern-limit population (Quiberon) showed a high propensity for producing unreduced (2N) spores. Unreduced 2N spores formed phenotypically normal gametophytes with nuclear area consistent with ≥2N DNA contents, and microsatellite studies suggested these were produced at least in part by automixis. However, despite this being the dominant path of spore production in Quiberon sporophyte individuals, the genetic evidence indicated the population was maintained mostly by sexual reproduction. Thus, although spore production and development showed the expected tendency of geographical parthenogenesis in marginal populations, this appeared to be a consequence of maladaptation, rather than an adaptation to, life in a marginal habitat.

Published
2014
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12. Universal loop assembly: open, efficient and cross-kingdom DNA fabrication

Author

Ariel Cerda, Isaac Núñez, Tamara Matute, Constanza Lopez, Valentina Vargas, Peter von Dassow, Christopher L. Dupont, Bernardo Pollak, Anton Kan, Vincent A. Bielinski, and Fernán Federici

Subjects
0106 biological sciences, openMTA, Computer science, Distributed computing, Interoperability, Biomedical Engineering, Bioengineering, freedom to use, 01 natural sciences, Personalization, law.invention, Biomaterials, 03 medical and health sciences, Synthetic biology, Plasmid, open source, law, 010608 biotechnology, DNA assembly, 030304 developmental biology, 0303 health sciences, Syntax (programming languages), LOOP (programming language), Interchangeable parts, Agricultural and Biological Sciences (miscellaneous), synthetic biology, Host (network), Biotechnology, Research Article
Abstract

Standardized type IIS DNA assembly methods are becoming essential for biological engineering and research. These methods are becoming widespread and more accessible due to the proposition of a ‘common syntax’ that enables higher interoperability between DNA libraries. Currently, Golden Gate (GG)-based assembly systems, originally implemented in host-specific vectors, are being made compatible with multiple organisms. We have recently developed the GG-based Loop assembly system for plants, which uses a small library and an intuitive strategy for hierarchical fabrication of large DNA constructs (>30 kb). Here, we describe ‘universal Loop’ (uLoop) assembly, a system based on Loop assembly for use in potentially any organism of choice. This design permits the use of a compact number of plasmids (two sets of four odd and even vectors), which are utilized repeatedly in alternating steps. The elements required for transformation/maintenance in target organisms are also assembled as standardized parts, enabling customization of host-specific plasmids. Decoupling of the Loop assembly logic from the host-specific propagation elements enables universal DNA assembly that retains high efficiency regardless of the final host. As a proof-of-concept, we show the engineering of multigene expression vectors in diatoms, yeast, plants and bacteria. These resources are available through the OpenMTA for unrestricted sharing and open access.

Published
2020

13. Genetic tool development in marine protists: Emerging model organisms for experimental cell biology

Author

Deepak Nanjappa, Iñaki Ruiz-Trillo, Christopher J. Howe, Chris Bowler, Mariusz Nowacki, Anastasios D. Tsaousis, Noelia Lander, Christopher L. Dupont, Shinichiro Maruyama, Fulei Luan, Andrew E. Allen, Anna M. G. Novák Vanclová, Pamela A. Silver, Nastasia J. Freyria, Peter von Dassow, Elisabeth Hehenberger, Konomi Fujimura-Kamada, Julius Lukeš, Roberto Docampo, Deborah L. Robertson, Thomas E. Clemente, Sebastián R. Najle, Kathryn J. Coyne, Cristina Aresté, Brittany N. Sprecher, Lu Wang, Eleanna Kazana, Verónica Freire-Benéitez, Vladimír Hampl, Cecilia Balestreri, Isabel C. Nimmo, Mariana Rius, Yoshihisa Hirakawa, Arnab Pain, Jorge Ibañez, Elin Einarsson, Lev Tsypin, Heriberto Cerutti, Adrian C. Barbrook, G. Jason Smith, Alexandra Z. Worden, Jian Guo, Jean Claude Lozano, Virginia P. Edgcomb, Huan Zhang, Andrea Highfield, Isaac Núñez, Fatma Gomaa, Jan Pyrih, Natalia Ewa Janowicz, Sara J. Bender, Ross F. Waller, Tobias von der Haar, François-Yves Bouget, Matus Valach, Amanda Hopes, Luke M. Noble, Paulo A. Garcia, Nicholas A.T. Irwin, Tamara Matute, Jernej Turnšek, Ian Hu, Sandra Pucciarelli, Fernán Federici, Valérie Vergé, R. Ellen R. Nisbet, Miguel Angel Chiurillo, Mark Moosburner, Monika Abedin Sigg, Aaron P. Turkewitz, Albane Ruaud, Angela Piersanti, Sebastian G. Gornik, Peter R. Girguis, Adam C. Jones, Lawrence A. Klobutcher, Claudio H. Slamovits, Elena Casacuberta, Imen Lassadi, Elizabeth C. Cooney, Kodai Fukuda, Nicole King, Manuel Ares, Jonathan Z. Kaye, Lisa Sudek, Patrick Beardslee, Cristina Miceli, Xiaoxue Wen, Estienne C. Swart, Yuu Ishii, Ambar Kachale, Pia A. Elustondo, Esteban R. Haro-Contreras, Patrick J. Keeling, José A. Fernández Robledo, Glen L. Wheeler, Colin Brownlee, Rowena Stern, Joshua S. Rest, Susana A. Breglia, Senjie Lin, Duncan B. Coles, Jackie L. Collier, Drahomíra Faktorová, David S. Booth, April Woods, Binnypreet Kaur, Thomas Mock, Gertraud Burger, Jun Minagawa, Yutaka Hanawa, Zhu-Hong Li, Rachele Cesaroni, Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Faktorová, Drahomíra [0000-0001-9623-2233], Nisbet, R. Ellen R. [0000-0003-4487-196X], Allen, Andrew E. [0000-0001-5911-6081], Ares, Manuel, Jr [0000-0002-2552-9168], Bowler, Chris [0000-0003-3835-6187], Burger, Gertraud [0000-0002-8679-8812], Collier, Jackie L. [0000-0001-8774-5715], Cooney, Elizabeth C. [0000-0001-7435-7609], Docampo, Roberto [0000-0003-4229-8784], Dupont, Christopher L. [0000-0002-0896-6542], Edgcomb, Virginia [0000-0001-6805-381X], Freyria, Nastasia J. [0000-0002-4972-9383], Gornik, Sebastian G. [0000-0002-8026-1336], Howe, Christopher J. [0000-0002-6975-8640], Hu, Ian [0000-0002-2287-031X], Ishii, Yuu [0000-0003-1735-9557], Jones, Adam C. [0000-0001-7521-1863], Lin, Senjie [0000-0001-8831-6111], Maruyama, Shinichiro [0000-0002-1128-5916], Minagawa, Jun [0000-0002-3028-3203], Najle, Sebastián R. [0000-0002-0654-9147], Nowacki, Mariusz [0000-0003-4894-2905], Pain, Arnab [0000-0002-1755-2819], Silver, Pamela A. [0000-0002-7856-4071], Jason Smith, G. [0000-0003-1258-4800], Sprecher, Brittany N. [0000-0001-5032-3834], Tsaousis, Anastasios D. [0000-0002-5424-1905], Tsypin, Lev [0000-0002-0642-8468], Turkewitz, Aaron [0000-0003-3531-5806], Turnšek, Jernej [0000-0002-9056-3565], Valach, Matus [0000-0001-8689-0080], von der Haar, Tobias [0000-0002-6031-9254], Mock, Thomas [0000-0001-9604-0362], Worden, Alexandra Z. [0000-0002-9888-9324], Lukeš, Julius [0000-0002-0578-6618], Apollo - University of Cambridge Repository, Nisbet, R Ellen R [0000-0003-4487-196X], Allen, Andrew E [0000-0001-5911-6081], Ares, Manuel [0000-0002-2552-9168], Collier, Jackie L [0000-0001-8774-5715], Cooney, Elizabeth C [0000-0001-7435-7609], Dupont, Christopher L [0000-0002-0896-6542], Freyria, Nastasia J [0000-0002-4972-9383], Gornik, Sebastian G [0000-0002-8026-1336], Howe, Christopher J [0000-0002-6975-8640], Jones, Adam C [0000-0001-7521-1863], Najle, Sebastián R [0000-0002-0654-9147], Silver, Pamela A [0000-0002-7856-4071], Jason Smith, G [0000-0003-1258-4800], Sprecher, Brittany N [0000-0001-5032-3834], Tsaousis, Anastasios D [0000-0002-5424-1905], Worden, Alexandra Z [0000-0002-9888-9324], Gordon and Betty Moore Foundation, Leverhulme Trust, Ministry of Education, Youth and Sports (Czech Republic), and European Commission

Subjects
Resource, Molecular biology, Range (biology), Tree of life (biology), [SDV]Life Sciences [q-bio], Green Fluorescent Proteins, ved/biology.organism_classification_rank.species, Marine Biology, Environment, Diversification (marketing strategy), Biology, Models, Biological, Biochemistry, Genome, 03 medical and health sciences, Transformation, Genetic, 0302 clinical medicine, Species Specificity, Genome editing, 631/1647/767/722, Ecosystem, 14. Life underwater, Model organism, Molecular Biology, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, 0303 health sciences, Dna delivery, 030306 microbiology, ved/biology, Cellular pathways, Eukaryota, Genetic systems, Biodiversity, DNA, Cell Biology, Genetic models, biology.organism_classification, Cell biology, QR, Transformation (genetics), Eukaryote, 030217 neurology & neurosurgery, 631/337, Biotechnology
Abstract

Diverse microbial ecosystems underpin life in the sea. Among these microbes are many unicellular eukaryotes that span the diversity of the eukaryotic tree of life. However, genetic tractability has been limited to a few species, which do not represent eukaryotic diversity or environmentally relevant taxa. Here, we report on the development of genetic tools in a range of protists primarily from marine environments. We present evidence for foreign DNA delivery and expression in 13 species never before transformed and for advancement of tools for eight other species, as well as potential reasons for why transformation of yet another 17 species tested was not achieved. Our resource in genetic manipulation will provide insights into the ancestral eukaryotic lifeforms, general eukaryote cell biology, protein diversification and the evolution of cellular pathways., This collaborative effort was supported by the Gordon and Betty Moore Foundation EMS Program of the Marine Microbiology Initiative (grant nos. GBMF4972 and 4972.01 to F.-Y.B.; GBMF4970 and 4970.01 to M.A. and A.Z.W.; GBMF3788 to A.Z.W.; GBMF 4968 and 4968.01 to H.C.; GBMF4984 to V.H.; GBMF4974 and 4974.01 to C. Brownlee; GBMF4964 to Y. Hirakawa; GBMF4961 to T. Mock; GBMF4958 to P.S.; GBMF4957 to A.T.; GBMF4960 to G.J.S.; GBMF4979 to K.C.; GBMF4982 and 4982.01 to J.L.C.; GBMF4964 to P.J.K.; GBMF4981 to P.v.D.; GBMF5006 to A.E.A.; GBMF4986 to C.M.; GBMF4962 to J.A.F.R.; GBMF4980 and 4980.01 to S.L.; GBMF 4977 and 4977.01 to R.F.W.; GBMF4962.01 to C.H.S.; GBMF4985 to J.M.; GBMF4976 and 4976.01 to C.H.; GBMF4963 and 4963.01 to V.E.; GBMF5007 to C.L.D.; GBMF4983 and 4983.01 to J.L.; GBMF4975 and 4975.01 to A.D.T.; GBMF4973 and 4973.01 to I.R.-T. and GBMF4965 to N.K.), by The Leverhulme Trust (RPG-2017-364) to T. Mock and A. Hopes, and by ERD funds (16_019/0000759) from the Czech Ministry of Education to J.L.

Published
2020
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14. Universal Loop assembly (uLoop): open, efficient, and species-agnostic DNA fabrication

Author

Peter von Dassow, Christopher L. Dupont, Bernardo Pollak, Isaac Núñez, Tamara Matute, Vincent A. Bielinski, Valentina Vargas, Constanza Lopez, Ariel Cerda, Anton Kan, and Fernán Federici

Subjects
Expression vector, biology, Syntax (programming languages), LOOP (programming language), Computer science, Distributed computing, biology.organism_classification, computer.software_genre, Yeast, chemistry.chemical_compound, Plasmid, chemistry, Compiler, computer, Organism, Bacteria, DNA
Abstract

Standardised Type IIS DNA assembly methods are becoming essential for biological engineering and research. Although a ‘common syntax’ has been proposed to enable higher interoperability between DNA libraries, Golden Gate (GG)-based assembly systems remain specific to target organisms. Furthermore, these GG assembly systems become laborious and unnecessarily complicated beyond the assembly of 4 transcriptional units. Here, we describe “universal Loop” (uLoop) assembly, a simple system based on Loop assembly that enables hierarchical fabrication of large DNA constructs (> 30 kb) for any organism of choice. uLoop comprises two sets of four plasmids that are iteratively used as odd and even levels to compile DNA elements in an exponential manner (4n-1). The elements required for transformation/maintenance in target organisms are also assembled as standardised parts, enabling customisation of host-specific plasmids. Thus, this species-agnostic method decouples efficiency of assembly from the stability of vectors in the target organism. As a proof-of-concept, we show the engineering of multi-gene expression vectors in diatoms, yeast, plants and bacteria. These resources will become available through the OpenMTA for unrestricted sharing and open-access.Abstract Figure

Published
2019
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15. Nitrogen assimilation in picocyanobacteria inhabiting the oxygen‐deficient waters of the eastern tropical North and South Pacific

Author

Margaret R. Mulholland, Qixing Ji, Bess B. Ward, Jessica A. Lueders-Dumont, Peter von Dassow, Carlos Henríquez-Castillo, Montserrat Aldunate, Osvaldo Ulloa, Universidad de Concepción [Chile], Princeton University, Old Dominion University [Norfolk] (ODU), Evolutionary Biology and Ecology of Algae (EBEA), Pontificia Universidad Católica de Chile (UC)-Sorbonne Université (SU)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0303 health sciences, Oxygen deficient, 030306 microbiology, Ecology, Chemistry, Nitrogen assimilation, Aquatic Science, Oceanography, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, 03 medical and health sciences, 13. Climate action, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 030304 developmental biology
Abstract

Prochlorococcus and Synechococcus are the most abundant free-living photosynthetic microorganisms in the ocean. Uncultivated lineages of these picocyanobacteria also thrive in the dimly illuminated upper part of oxygen-deficient zones (ODZs), where an important portion of ocean nitrogen (N) loss takes place via denitrification and anaerobic ammonium oxidation. Recent metagenomic studies revealed that ODZ Prochlorococcus have the genetic potential for using different N forms, including nitrate and nitrite, uncommon N sources for Prochlorococcus, but common for Synechococcus. To determine which N sources ODZ picocyanobacteria are actually using in nature, the cellular N-15 natural abundance (delta N-15) and assimilation rates of different N compounds were determined using cell sorting by flow cytometry and mass spectrometry. The natural delta N-15 of the ODZ Prochlorococcus varied from -4.0 parts per thousand to 13.0 parts per thousand (n = 9), with 50% of the values in the range of -2.1-2.6 parts per thousand. While the highest values suggest nitrate use, most observations indicate the use of nitrite, ammonium, or a mixture of N sources. Meanwhile, incubation experiments revealed potential assimilation rates of ammonium and urea in the same order of magnitude as that expected for total N in several environments including ODZs, whereas rates of nitrite and nitrate assimilation were very low. Our results thus indicate that reduced forms of N and nitrite are the dominant sources for ODZ picocyanobacteria, although nitrate might be important on some occasions. ODZ picocyanobacteria might thus represent potential competitors with anammox bacteria for ammonium and nitrite, with ammonia-oxidizing archaea for ammonium, and with nitrite-oxidizing bacteria for nitrite.

Published
2019
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16. Publisher Correction: Genetic tool development in marine protists: emerging model organisms for experimental cell biology

Author

Claudio H. Slamovits, Gertraud Burger, Patrick J. Keeling, Jian Guo, Fatma Gomaa, Jan Pyrih, Jun Minagawa, Christopher L. Dupont, Verónica Freire-Benéitez, Nastasia J. Freyria, Rachele Cesaroni, Elizabeth C. Cooney, Eleanna Kazana, Aaron P. Turkewitz, Peter R. Girguis, Konomi Fujimura-Kamada, Chris Bowler, Anastasios D. Tsaousis, Pamela A. Silver, Lawrence A. Klobutcher, Tamara Matute, Shinichiro Maruyama, Nicole King, Virginia P. Edgcomb, Roberto Docampo, Isaac Núñez, Deborah L. Robertson, Xiaoxue Wen, Zhu-Hong Li, Huan Zhang, Jorge Ibañez, Kathryn J. Coyne, Jonathan Z. Kaye, Christopher J. Howe, Andrew E. Allen, Ross F. Waller, Brittany N. Sprecher, R. Ellen R. Nisbet, Mark Moosburner, Alexandra Z. Worden, Thomas Mock, Angela Piersanti, Sebastian G. Gornik, Paulo A. Garcia, Amanda Hopes, Isabel C. Nimmo, Mariana Rius, Estienne C. Swart, Nicholas A.T. Irwin, Elisabeth Hehenberger, Valérie Vergé, Andrea Highfield, Sandra Pucciarelli, François-Yves Bouget, Yutaka Hanawa, Matus Valach, April Woods, Elin Einarsson, Anna M. G. Novák Vanclová, Lu Wang, Fernán Federici, Monika Abedin Sigg, Adrian C. Barbrook, Yoshihisa Hirakawa, G. Jason Smith, Adam C. Jones, Deepak Nanjappa, Vladimír Hampl, Binnypreet Kaur, Thomas E. Clemente, Jernej Turnšek, Jean Claude Lozano, Sara J. Bender, Ian Hu, Sebastián R. Najle, Imen Lassadi, Glen L. Wheeler, Cecilia Balestreri, Fulei Luan, Lev Tsypin, Heriberto Cerutti, Miguel Angel Chiurillo, Colin Brownlee, Rowena Stern, Julius Lukeš, Manuel Ares, Drahomíra Faktorová, Kodai Fukuda, David S. Booth, Peter von Dassow, Elena Casacuberta, Patrick Beardslee, Cristina Miceli, Cristina Aresté, Natalia Ewa Janowicz, Joshua S. Rest, Susana A. Breglia, Senjie Lin, Luke M. Noble, Albane Ruaud, Duncan B. Coles, Pia A. Elustondo, Jackie L. Collier, Lisa Sudek, Yuu Ishii, José A. Fernández Robledo, Noelia Lander, Tobias von der Haar, Ambar Kachale, Esteban R. Haro-Contreras, Arnab Pain, Iñaki Ruiz-Trillo, and Mariusz Nowacki

Subjects
biology, Molecular biology, media_common.quotation_subject, Garcia, Green Fluorescent Proteins, Drahomira, Eukaryota, Marine Biology, Cell Biology, Art, Biodiversity, DNA, Environment, biology.organism_classification, Genetic models, Biochemistry, Publisher Correction, Models, Biological, Transformation, Genetic, Species Specificity, Humanities, Ecosystem, Biotechnology, media_common
Abstract

Author(s): Faktorova, Drahomira; Nisbet, R Ellen R; Fernandez Robledo, Jose A; Casacuberta, Elena; Sudek, Lisa; Allen, Andrew E; Ares, Manuel; Areste, Cristina; Balestreri, Cecilia; Barbrook, Adrian C; Beardslee, Patrick; Bender, Sara; Booth, David S; Bouget, Francois-Yves; Bowler, Chris; Breglia, Susana A; Brownlee, Colin; Burger, Gertraud; Cerutti, Heriberto; Cesaroni, Rachele; Chiurillo, Miguel A; Clemente, Thomas; Coles, Duncan B; Collier, Jackie L; Cooney, Elizabeth C; Coyne, Kathryn; Docampo, Roberto; Dupont, Christopher L; Edgcomb, Virginia; Einarsson, Elin; Elustondo, Pia A; Federici, Fernan; Freire-Beneitez, Veronica; Freyria, Nastasia J; Fukuda, Kodai; Garcia, Paulo A; Girguis, Peter R; Gomaa, Fatma; Gornik, Sebastian G; Guo, Jian; Hampl, Vladimir; Hanawa, Yutaka; Haro-Contreras, Esteban R; Hehenberger, Elisabeth; Highfield, Andrea; Hirakawa, Yoshihisa; Hopes, Amanda; Howe, Christopher J; Hu, Ian; Ibanez, Jorge; Irwin, Nicholas AT; Ishii, Yuu; Janowicz, Natalia Ewa; Jones, Adam C; Kachale, Ambar; Fujimura-Kamada, Konomi; Kaur, Binnypreet; Kaye, Jonathan Z; Kazana, Eleanna; Keeling, Patrick J; King, Nicole; Klobutcher, Lawrence A; Lander, Noelia; Lassadi, Imen; Li, Zhuhong; Lin, Senjie; Lozano, Jean-Claude; Luan, Fulei; Maruyama, Shinichiro; Matute, Tamara; Miceli, Cristina; Minagawa, Jun; Moosburner, Mark; Najle, Sebastian R; Nanjappa, Deepak; Nimmo, Isabel C; Noble, Luke; Novak Vanclova, Anna MG; Nowacki, Mariusz; Nunez, Isaac; Pain, Arnab; Piersanti, Angela; Pucciarelli, Sandra; Pyrih, Jan; Rest, Joshua S | Abstract: An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Published
2020

17. Differences in the sensitivity to cu and ligand production of coastal vs offshore strains of emiliania huxleyi

Author

Pedro Echeveste, Peter Croot, and Peter von Dassow

Subjects
0106 biological sciences, Environmental Engineering, 010504 meteorology & atmospheric sciences, Biology, Ligands, 01 natural sciences, Intraspecific competition, Sedimentary depositional environment, Mediterranean sea, Phytoplankton, Mediterranean Sea, Environmental Chemistry, Trace metal, Waste Management and Disposal, 0105 earth and related environmental sciences, Emiliania huxleyi, Pacific Ocean, 010604 marine biology & hydrobiology, fungi, Haptophyta, Pelagic zone, biology.organism_classification, Pollution, Oceanography, Submarine pipeline, Copper
Abstract

Copper is an essential trace metal for different physiological processes in phytoplankton, being either a limiting or toxic element depending on its bioavailability, which may induce local physiological adaptations. Atmospheric Cu deposition to the oceans can negatively impact phytoplankton growth, with the most Cu-sensitive phytoplankton exhibiting differences based on coastal vs oceanic origin. The goal of this work was to analyze sensitivity to Cu toxicity of the cosmopolitan marine calcifying phytoplankton, Emiliania huxleyi , exploring what factors determine intraspecific variability in sensitivity. We compared 17 strains isolated from coastal and open ocean waters of the Eastern South Pacific (ESP), the Mediterranean Sea, and the Tasman Sea. Offshore strains were as sensitive to Cu than coastal strains. Sensitivity to Cu was explained well by predicted depositional inputs of atmospheric Cu in the ESP both for coastal and offshore strains, but not when considered globally. The variability in Cu-sensitivity was also due to the production of organic Cu-ligands (CL), being the most productive strains the most tolerant to Cu at constitutive levels. When exposed to 100 nM Cu, E. huxleyi produced significantly higher amounts of CL, especially coastal strains, but CL production did not correlate to observed EC50s.

Published
2018

18. Impact of low pH/high pCO2 on the physiological response and fatty acid content in the diatom Skeletonema pseudocostatum

Author

Cristian A. Vargas, Joe Salisbury, Peter von Dassow, Bárbara Jacob, and Jorge M. Navarro

Subjects
0106 biological sciences, chemistry.chemical_classification, Total organic carbon, Ecophysiology, 010504 meteorology & atmospheric sciences, biology, Chemistry, 010604 marine biology & hydrobiology, Fatty acid, Ocean acidification, Aquatic Science, biology.organism_classification, Photosynthesis, 01 natural sciences, Diatom, Environmental chemistry, Botany, Dissolved organic carbon, Respiration, 0105 earth and related environmental sciences
Abstract

pCO2/pH perturbation experiments were carried out under two different pCO2 levels to evaluate effects of CO2-driven ocean acidification on semi-continuous cultures of the marine diatom Skeletonema pseudocostatum CSA48. Under higher pCO2/lowered pH conditions, our results showed that CO2-driven acidification had no significant impact on growth rate, chlorophyll-a, cellular abundance, gross photosynthesis, dark respiration, particulate organic carbon and particulate organic nitrogen between CO2-treatments, suggesting that S. pseudocostatum is adapted to tolerate changes of ~0.5 units of pH under high pCO2 conditions. However, dissolved organic carbon (DOC) concentration and DOC/POC ratio were significantly higher at high pCO2, indicating that a greater partitioning of organic carbon into the DOC pool was stimulated by high CO2/low pH conditions. Total fatty acids (FAs) were significantly higher under low pCO2 conditions. The composition of FAs changed from low to high pCO2, with an increase in the concentration of saturated and a reduction of monounsaturated FAs. Polyunsaturated FAs did not show significant differences between pCO2 treatments. Our results lead to the conclusion that the balance between negative or null effect on S. pseudocostatum ecophysiology upon low pH/high pCO2 conditions constitute an important factor to be considered in order to evaluate the global effect of rising atmospheric CO2 on primary productivity in coastal ocean. We found a significant decrease in total FAs, however no indications were found for a detrimental effect of ocean acidification on the nutritional quality in terms of essential fatty acids.

Published
2017

19. Emiliania huxleyi endures N-limitation with an efficient metabolic budgeting and effective ATP synthesis

Author

Peter von Dassow, Björn Rost, Sebastian D. Rokitta, Uwe John, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Pontificia Universidad Católica de Chile (UC), Evolutionary Biology and Ecology of Algae (EBEA), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS)-Pontificia Universidad Católica de Chile (UC), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Pontificia Universidad Católica de Chile (UC)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Nitrogen, Respiratory chain, Haploidy, Emiliania huxleyi, Microarray, Photosynthesis, 01 natural sciences, Electron Transport, Transcriptome, 03 medical and health sciences, Adenosine Triphosphate, Nutrient, Lipid oxidation, Genetics, Polyamines, Transcriptomics, 030304 developmental biology, 0303 health sciences, Malate:quinone-oxidoreductase, biology, Phototroph, Gene Expression Profiling, 010604 marine biology & hydrobiology, fungi, Haptophyta, Proline oxidation, Limitation, biology.organism_classification, Diploidy, Carbon, Diatom, Metabolism, Biochemistry, Protein Biosynthesis, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Energy Metabolism, Metabolic Networks and Pathways, Ornithine-urea-cycle, Research Article, Biotechnology
Abstract

Background Global change will affect patterns of nutrient upwelling in marine environments, potentially becoming even stricter regulators of phytoplankton primary productivity. To better understand phytoplankton nutrient utilization on the subcellular basis, we assessed the transcriptomic responses of the life-cycle stages of the biogeochemically important microalgae Emiliania huxleyi to nitrogen-limitation. Cells grown in batch cultures were harvested at ‘early’ and ‘full’ nitrogen-limitation and were compared with non-limited cells. We applied microarray-based transcriptome profilings, covering ~10.000 known E. huxleyi gene models, and screened for expression patterns that indicate the subcellular responses. Results The diploid life-cycle stage scavenges nitrogen from external organic sources and -like diatoms- uses the ornithine-urea cycle to rapidly turn over cellular nitrogen. The haploid stage reacts similarly, although nitrogen scavenging is less pronounced and lipid oxidation is more prominent. Generally, polyamines and proline appear to constitute major organic pools that back up cellular nitrogen. Both stages induce a malate:quinone-oxidoreductase that efficiently feeds electrons into the respiratory chain and drives ATP generation with reduced respiratory carbon throughput. Conclusions The use of the ornithine-urea cycle to budget the cellular nitrogen in situations of limitation resembles the responses observed earlier in diatoms. This suggests that underlying biochemical mechanisms are conserved among distant clades of marine phototrophic protists. The ornithine-urea cycle and proline oxidation appear to constitute a sensory-regulatory system that monitors and controls cellular nitrogen budgets under limitation. The similarity between the responses of the life-cycle stages, despite the usage of different genes, also indicates a strong functional consistency in the responses to nitrogen-limitation that appears to be owed to biochemical requirements. The malate:quinone-oxidoreductase is a genomic feature that appears to be absent from diatom genomes, and it is likely to strongly contribute to the uniquely high endurance of E. huxleyi under nutrient limitation. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1051) contains supplementary material, which is available to authorized users.

Published
2014
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20. Metagenome Sequencing of the Microbial Community of a Solar Saltern Crystallizer Pond at Cahuil Lagoon, Chile

Author

Daniel Vaulot, Marine Blanchet, Marcia Astorga, Carlos Henríquez-Castillo, Gerrit van den Engh, María Lorena González, Priscila Ikeda, Claudia Elizondo-Patrone, Florencia Bertoglio, Felipe Docmac, Nicole Trefault, María Jesús Gálvez, Fernando Guido Sorroche, Silvia Narváez, Yolaine Delgado, Rodrigo De la Iglesia, Francisco Santibañez, Kurt Hanselmann, Eric E. Allen, Osvaldo Ulloa, Nathalie Delherbe, Marcelo Rojas-Herrera, Alvaro M. Plominsky, Peter von Dassow, Juan A. Ugalde, Adriana Lopes do Santos, Carla Gimpel, Pontificia Universidad Católica de Chile (UC), Facultad de Ciencias, Marine Biology Research Division, University of California [San Diego] (UC San Diego), University of California-University of California-Scripps Institution of Oceanography, Division of Biological Sciences [San Diego], University of California-University of California, Biogeochemistry and Microbiology, Polytechnic School of the University of São Paulo (Brazil), Universidade de São Paulo (USP), Universidad de Concepción [Chile], Geological Institute [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Departmento de Oceanografía & Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental, Diversité et Interactions au sein du Plancton Océanique (DIPO), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Biomedical Research Center in Bioengineering, Biomaterials, and Nanomedicine ( (CIBER-BBN), Biomedical Research Center, Biomedical Image Technologies Lab, ETSI Telecomunicación, Universidad Politécnica de Madrid (UPM), BD Advanced Cytometry Group, Instituto Antartico Chileno, Centro Universitario Regional Este, Universidad de La Habana [Cuba], Facultad de Ciencias del Mar y Recursos Biológicos, Departamento de Ecologıa y Recursos Naturales, Instituto de Investigaciones Marinas y Costeras 'José Benito Vives de Andréis' (INVEMAR), Ministerio del Medio Ambiente, Colombie, Facultad de Ciencias Exactas y Naturales [Mar del Plata], Universidad Nacional de Mar del Plata [Mar del Plata] (UNMdP), Scripps Institution of Oceanography (SIO - UC San Diego), University of California (UC)-University of California (UC)-University of California [San Diego] (UC San Diego), University of California (UC)-University of California (UC), School of Biological Sciences [Univ California San Diego] (UC San Diego), Universidade de São Paulo = University of São Paulo (USP), and Universidad de Concepción - University of Concepcion [Chile]

Subjects
0303 health sciences, 030306 microbiology, Ecology, [SDV]Life Sciences [q-bio], education, fungi, Biology, Microbiology, Salinity, 03 medical and health sciences, Microbial population biology, Metagenomics, parasitic diseases, [SDE]Environmental Sciences, Genetics, Prokaryotes, Biochemistry and Cell Biology, Molecular Biology, 030304 developmental biology
Abstract

Cáhuil Lagoon in central Chile harbors distinct microbial communities in various solar salterns that are arranged as interconnected ponds with increasing salt concentrations. Here, we report the metagenome of the 3.0- to 0.2-µm fraction of the microbial community present in a crystallizer pond with 34% salinity.

Published
2014
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21. In Situ Tolerance within the Central Nervous System as a Mechanism for Preventing Autoimmunity

Author

Peter von Dassow, Nadia Ordonez, Thea Brabb, Bryan Schnabel, Blythe Duke, and Joan Goverman

Subjects
Central Nervous System, Multiple Sclerosis, T cell, Genes, RAG-1, T-Lymphocytes, Immunology, Receptors, Antigen, T-Cell, Mice, Transgenic, Biology, Immune tolerance, Interleukin 21, Mice, Antigen, trafficking, medicine, Immune Tolerance, Immunology and Allergy, Cytotoxic T cell, Animals, Crosses, Genetic, transgenic, Homeodomain Proteins, Mice, Knockout, T-cell receptor, experimental allergic encephalomyelitis, CD28, Myelin Basic Protein, Myelin basic protein, Mice, Inbred C57BL, medicine.anatomical_structure, biology.protein, Original Article
Abstract

Multiple sclerosis (MS) is believed to be an autoimmune disease in which autoreactive T cells infiltrate the central nervous system (CNS). Animal models of MS have shown that CNS-specific T cells are present in the peripheral T cell repertoire of healthy mice and cause autoimmune disease only when they are activated by immunization. T cell entry into the CNS is thought to require some form of peripheral activation because the blood–brain barrier prohibits trafficking of this tissue by naive cells. We report here that naive T cells can traffic to the CNS without prior activation. Comparable numbers of T cells are found in the CNS of both healthy recombinase activating gene (Rag)−/− T cell receptor (TCR) transgenic mice and nontransgenic mice even when the transgenic TCR is specific for a CNS antigen. Transgenic T cells isolated from the CNS that are specific for non-CNS antigens are phenotypically naive and proliferate robustly to antigenic stimulation in vitro. Strikingly, transgenic T cells isolated from the CNS that are specific for myelin basic protein (MBP) are also primarily phenotypically naive but are unresponsive to antigenic stimulation in vitro. Mononuclear cells from the CNS of MBP TCR transgenic but not nontransgenic mice can suppress the response of peripheral MBP-specific T cells in vitro. These results indicate that naive MBP-specific T cells can traffic to the CNS but do not trigger autoimmunity because they undergo tolerance induction in situ.

Published
2000

22. The Ectocarpus genome and the independent evolution of multicellularity in brown algae

Author

Jean-Marc Aury, Frithjof C. Küpper, Diego Miranda-Saavedra, John H. F. Bothwell, Claire Jubin, Chris Bowler, Bernhard Gschloessl, James W. Tregear, Andrés Ritter, Andrew E. Allen, Carolyn A. Napoli, Ludovic Delage, Bernard Kloareg, Takahiro Yamagishi, Pi Nyvall-Collén, Svenja Heesch, Julia Morales, Gaelle Samson, Kei Kimura, Ga Youn Cho, Grigoris D. Amoutzias, Yves Van de Peer, Simon M. Dittami, Kenny Billiau, Julie Poulain, François Artiguenave, Sylvie Doulbeau, Marek Eliáš, Bank Beszteri, Carl J. Carrano, Daniel Lang, Florian Maumus, Stefan A. Rensing, Jonathan H. Badger, Béatrice Segurens, Martina Strittmatter, Sylvie Rousvoal, Hervé Moreau, Patrice Lerouge, Colin Brownlee, Betsy Read, Akira F. Peters, J. Mark Cock, Corinne Da Silva, Declan C. Schroeder, Catherine Boyen, Pierre Rouzé, Eric Bonnet, Jonas Collén, Susana M. Coelho, Aude Le Bail, Kamel Jabbari, David R. Nelson, Thierry Tonon, Pascal J. Lopez, Véronique Anthouard, Hadi Quesneville, Manoj P. Samanta, Delphine Scornet, Klaus Valentin, Nicolas Delaroque, Bénédicte Charrier, Cindy Martens, Peter von Dassow, Martin Lohr, Garry Farnham, Chikako Nagasato, Claire M. M. Gachon, Gurvan Michel, Lieven Sterck, Philippe Potin, Erwan Corre, Catherine Leblanc, Taizo Motomura, Cyril Pommier, Patrick Wincker, Hiroshi Kawai, Publica, Végétaux marins et biomolécules, Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-GOEMAR-Centre National de la Recherche Scientifique (CNRS), Department of Plant Systems Biology, State University of Ghent, J Craig Venter Institute, Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Marine Biological Association, Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), San Diego State University (SDSU), Phophorylation de protéines et Pathologies Humaines (P3H), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Fraunhofer Institute for Cell Therapy and Immunology (IZI), Diversité et adaptation des plantes cultivées (UMR DIAPC), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Charles University [Prague], Scottish Association for Marine Science (SAMS), Kobe University, Institute of Algological Research [Muroran], Hokkaido University, Fakultät für Biologie = Faculty of Biology [Freiburg], Albert-Ludwigs-Universität Freiburg, Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU), Johannes Gutenberg - Universität Mainz (JGU), École normale supérieure - Paris (ENS Paris), Institut de biologie de l'Ecole Normale Supérieure (IBENS), École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Department of Haematology, University of Cambridge [UK] (CAM), Mer et santé (MS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Arizona, The University of Tennessee Health Science Center [Memphis] (UTHSC), Unité de Recherche Génomique Info (URGI), Institut National de la Recherche Agronomique (INRA), California State University [Los Angeles] (CAL STATE LA), Laboratoire de Biotechnologie et Chimie Marines (LBCM), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Systemix Institute, Savelli, Bruno, Center for Plant Systems Biology (PSB Center), Vlaams Instituut voor Biotechnologie [Ghent, Belgique] (VIB), J. Craig Venter Institute, Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de biologie de l'ENS Paris (IBENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Adaptation et diversité en milieu marin (AD2M), Fraunhofer Institute for Cell Therapy and Immunology (Fraunhofer IZI), Fraunhofer (Fraunhofer-Gesellschaft), Charles University [Prague] (CU), Hokkaido University [Sapporo, Japan], Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Université Paris sciences et lettres (PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris

Subjects
0106 biological sciences, Lineage (evolution), Molecular Sequence Data, Phaeophyta, 01 natural sciences, Genome, Evolution, Molecular, 03 medical and health sciences, Algae, [SDV.BDD] Life Sciences [q-bio]/Development Biology, Botany, BIOLOGIE CELLULAIRE, Animals, 14. Life underwater, [SDV.BDD]Life Sciences [q-bio]/Development Biology, flore marine, Phylogeny, Organism, ComputingMilieux_MISCELLANEOUS, phéophycées, 030304 developmental biology, 0303 health sciences, Multidisciplinary, biology, Ectocarpus siliculosus, Algal Proteins, Eukaryota, Pigments, Biological, Ectocarpus, 15. Life on land, biology.organism_classification, Biological Evolution, Brown algae, Multicellular organism, Evolutionary biology, algues brunes, Biologie, Signal Transduction, 010606 plant biology & botany
Abstract

Brown algae (Phaeophyceae) are complex photosynthetic organisms with a very different evolutionary history to green plants, to which they are only distantly related. These seaweeds are the dominant species in rocky coastal ecosystems and they exhibit many interesting adaptations to these, often harsh, environments. Brown algae are also one of only a small number of eukaryotic lineages that have evolved complex multicellularity (Fig. 1). We report the 214 million base pair (Mbp) genome sequence of the filamentous seaweed Ectocarpus siliculosus (Dillwyn) Lyngbye, a model organism for brown algae, closely related to the kelps (Fig. 1). Genome features such as the presence of an extended set of light-harvesting and pigment biosynthesis genes and new metabolic processes such as halide metabolism help explain the ability of this organism to cope with the highly variable tidal environment. The evolution of multicellularity in this lineage is correlated with the presence of a rich array of signal transduction genes. Of particular interest is the presence of a family of receptor kinases, as the independent evolution of related molecules has been linked with the emergence of multicellularity in both the animal and green plant lineages. The Ectocarpus genome sequence represents an important step towards developing this organism as a model species, providing the possibility to combine genomic and genetic approaches to explore these and other aspects of brown algal biology further. © 2010 Macmillan Publishers Limited. All rights reserved.

Published
2010
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23. Transcriptome analysis of functional differentiation between haploid and diploid cells of Emiliania huxleyi, a globally significant photosynthetic calcifying cell

Author

Peter von Dassow, Ian Probert, Stéphane Audic, Patrick Wincker, Hiroyuki Ogata, Jean-Michel Claverie, Colomban de Vargas, Corinne Da Silva, Evolution des Protistes et Ecosystèmes Pélagiques (EPEP), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Information génomique et structurale (IGS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme [PIIF-GA-2008221812], Actions Thematique et Incitatives sur Programme (ATIP), Centre National de la Recherche Scientifique, France, French Agence Nationale de la Recherche [ANR-05-BIODIV-004], PACA-BioInfo Platform, and Marseille-Nice Genopole

Subjects
0106 biological sciences, Time Factors, [SDV]Life Sciences [q-bio], Haploidy, 01 natural sciences, Histones, Transcriptome, Histone H4, 03 medical and health sciences, Sequence Homology, Nucleic Acid, Cluster Analysis, 14. Life underwater, Photosynthesis, Gene, Gene Library, 030304 developmental biology, Emiliania huxleyi, Expressed Sequence Tags, Genetics, 0303 health sciences, Expressed sequence tag, biology, Reverse Transcriptase Polymerase Chain Reaction, cDNA library, Gene Expression Profiling, Research, 010604 marine biology & hydrobiology, Cell Cycle, fungi, Membrane Transport Proteins, Reproducibility of Results, Flow Cytometry, biology.organism_classification, Diploidy, Gene Expression Regulation, Mating of yeast, Flagella, Phytoplankton, [SDE]Environmental Sciences, Ploidy
Abstract

An EST analysis of the phytoplankton Emiliania huxleyi reveals genes involved in haploid- and diploid-specific processes and provides insights into environmental adaptation., Background Eukaryotes are classified as either haplontic, diplontic, or haplo-diplontic, depending on which ploidy levels undergo mitotic cell division in the life cycle. Emiliania huxleyi is one of the most abundant phytoplankton species in the ocean, playing an important role in global carbon fluxes, and represents haptophytes, an enigmatic group of unicellular organisms that diverged early in eukaryotic evolution. This species is haplo-diplontic. Little is known about the haploid cells, but they have been hypothesized to allow persistence of the species between the yearly blooms of diploid cells. We sequenced over 38,000 expressed sequence tags from haploid and diploid E. huxleyi normalized cDNA libraries to identify genes involved in important processes specific to each life phase (2N calcification or 1N motility), and to better understand the haploid phase of this prominent haplo-diplontic organism. Results The haploid and diploid transcriptomes showed a dramatic differentiation, with approximately 20% greater transcriptome richness in diploid cells than in haploid cells and only ≤ 50% of transcripts estimated to be common between the two phases. The major functional category of transcripts differentiating haploids included signal transduction and motility genes. Diploid-specific transcripts included Ca2+, H+, and HCO3- pumps. Potential factors differentiating the transcriptomes included haploid-specific Myb transcription factor homologs and an unusual diploid-specific histone H4 homolog. Conclusions This study permitted the identification of genes likely involved in diploid-specific biomineralization, haploid-specific motility, and transcriptional control. Greater transcriptome richness in diploid cells suggests they may be more versatile for exploiting a diversity of rich environments whereas haploid cells are intrinsically more streamlined.

Published
2009
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24. Phytoplankton calcification in a high-CO2 world

Author

Samantha J. Gibbs, Elena Colmenero-Hidalgo, Rosalind E. M. Rickaby, Peter von Dassow, Ian Hall, Darryl R H Green, Paul R. Halloran, Eric Rehm, Karin P. Boessenkool, E. Virginia Armbrust, John R. Gittins, Toby Tyrrell, and M. Debora Iglesias-Rodriguez

Subjects
0106 biological sciences, Geologic Sediments, 010504 meteorology & atmospheric sciences, Coccolithophore, Oceans and Seas, 01 natural sciences, Deep sea, Calcium Carbonate, Coccolith, Calcification, Physiologic, Phytoplankton, 14. Life underwater, Photosynthesis, 0105 earth and related environmental sciences, Emiliania huxleyi, Multidisciplinary, biology, Atmosphere, Ecology, 010604 marine biology & hydrobiology, fungi, Eukaryota, Global change, Ocean acidification, Carbon Dioxide, Hydrogen-Ion Concentration, Plankton, biology.organism_classification, Oceanography, 13. Climate action
Abstract

Ocean acidification in response to rising atmospheric CO 2 partial pressures is widely expected to reduce calcification by marine organisms. From the mid-Mesozoic, coccolithophores have been major calcium carbonate producers in the world's oceans, today accounting for about a third of the total marine CaCO 3 production. Here, we present laboratory evidence that calcification and net primary production in the coccolithophore species Emiliania huxleyi are significantly increased by high CO 2 partial pressures. Field evidence from the deep ocean is consistent with these laboratory conclusions, indicating that over the past 220 years there has been a 40% increase in average coccolith mass. Our findings show that coccolithophores are already responding and will probably continue to respond to rising atmospheric CO 2 partial pressures, which has important implications for biogeochemical modeling of future oceans and climate.

Published
2008

25. The $Phaeodactylum$ genome reveals the evolutionary history of diatom genomes

Author

Yves Van de Peer, Michael R. Sussman, Frédéric Verret, Miyoshi Haruta, Angela Falciatore, John A. Berges, Leszek Rychlewski, Anusuya Willis, Richard E. Jorgensen, Michael Katinka, Jane Grimwood, Betina M. Porcel, Magali Siaut, Klaus Valentin, Pascal J. Lopez, Marc Heijde, Véronique Martin-Jézéquel, Jean-Louis Petit, Wim Vyverman, Edda Rayko, Klaas Vandepoele, Miroslav Oborník, Anthony Chiovitti, Alan Kuo, E. Virginia Armbrust, Matthew Robison, Alessandra De Martino, Nils Kröger, Susan Lucas, Colin Brownlee, Alison Taylor, Igor V. Grigoriev, Jonathan H. Badger, Kamel Jabbari, Jérome Fournet, Jeremy Schmutz, Uma Maheswari, Sacha Coesel, Michele S. Stanley, J. Chris Detter, Chang Jae Choi, Thomas Mock, Assaf Vardi, Markus Lommer, Aaron Kaplan, Yolaine Joubert, Florian Maumus, Katerina Jiroutova, Anton Montsant, Colleen A. Durkin, Cindy Martens, Bank Beszteri, Micaela S. Parker, Asaf Salamov, Linda K. Medlin, Karen M. McGinnis, Ansgar Gruber, Marie J. J. Huysman, Manuela Mangogna, Lucyan S. Wyrwicz, Jean-Paul Cadoret, Peter von Dassow, Daniel S. Rokhsar, Marie-Pierre Oudot-Le Secq, Carolyn A. Napoli, Beverley R. Green, Erica Lindquist, Peter G. Kroth, Chris Bowler, Andrew E. Allen, Tatiana A. Rynearson, Nicole Poulsen, Bethany D. Jenkins, Harris Shapiro, Robert Otillar, Jean Weissenbach, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL), J. Craig Venter Institute, J. Craig Venter Institute [La Jolla, USA] (JCVI), Department of Energy / Joint Genome Institute (DOE), Los Alamos National Laboratory (LANL), DOE Joint Genome Institute [Walnut Creek], Center for Plant Systems Biology (PSB Center), Vlaams Instituut voor Biotechnologie [Ghent, Belgique] (VIB), Institut de biologie de l'Ecole Normale Supérieure (IBENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Biologie moléculaire des organismes photosynthétiques (UMR8186), Département de Biologie - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Environnement, Bioénergie, Microalgues et Plantes (EBMP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Marine Biological Association, Physiologie et biotechnologie des Algues (PBA), Biotechnologies et Ressources Marines (BRM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratory of Ecology and Evolution of Plankton, Stazione Zoologica Anton Dohrn (SZN), Génomique des Microorganismes (LGM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Marine Biogeochemistry, Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Biology Institute, University of Arizona, School of Oceanography [Seattle], University of Washington [Seattle], Stanford School of Medicine [Stanford], Stanford Medicine, Stanford University-Stanford University, Station biologique de Roscoff [Roscoff] (SBR), European Project: 29849,DIATOMICS, Savelli, Bruno, Understanding Diatom Biology by Functional Genomics Approaches - DIATOMICS - 29849 - OLD, École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Bioénergie et Microalgues (EBM), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Génomique des microorganismes, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)

Subjects
0106 biological sciences, Thalassiosira pseudonana, Molecular Sequence Data, 01 natural sciences, Genome, Evolution, Molecular, 03 medical and health sciences, DNA, Algal, Phylogenetics, [SDV.BID.EVO] Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], Gene family, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, [SDV.BV] Life Sciences [q-bio]/Vegetal Biology, 14. Life underwater, Phaeodactylum tricornutum, Gene, 030304 developmental biology, Genetics, Diatoms, 0303 health sciences, Multidisciplinary, biology, Sequence Homology, Amino Acid, Heterokont, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], fungi, biology.organism_classification, Protein Structure, Tertiary, Diatom, Genes, Bacterial, Biologie, 010606 plant biology & botany, Signal Transduction
Abstract

Diatoms are photosynthetic secondary endosymbionts found throughout marine and freshwater environments, and are believed to be responsible for around one-fifth of the primary productivity on Earth. The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology. Here we report the complete genome sequence of the pennate diatom Phaeodactylum tricornutum and compare it with that of T. pseudonana to clarify evolutionary origins, functional significance and ubiquity of these features throughout diatoms. In spite of the fact that the pennate and centric lineages have only been diverging for 90 million years, their genome structures are dramatically different and a substantial fraction of genes (

Published
2008
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26. Genome size differentiates co-occurring populations of the planktonic diatom Ditylum brightwellii (Bacillariophyta)

Author

Jarred E. Swalwell, Peter von Dassow, Julie A. Koester, E. Virginia Armbrust, School of Oceanography [Seattle], University of Washington [Seattle], Evolution des Protistes et Ecosystèmes Pélagiques (EPEP), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Species complex, Northwestern United States, Range (biology), Evolution, Genetic Speciation, media_common.quotation_subject, Population, 010603 evolutionary biology, 01 natural sciences, Genome, Evolution, Molecular, 03 medical and health sciences, DNA, Algal, Gene Duplication, Research article, QH359-425, education, Genome size, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 030304 developmental biology, media_common, Diatoms, 0303 health sciences, education.field_of_study, biology, Sequence Analysis, DNA, biology.organism_classification, Speciation, Ditylum brightwellii, Diatom, Genetics, Population, Evolutionary biology, New Zealand
Abstract

Background Diatoms are one of the most species-rich groups of eukaryotic microbes known. Diatoms are also the only group of eukaryotic micro-algae with a diplontic life history, suggesting that the ancestral diatom switched to a life history dominated by a duplicated genome. A key mechanism of speciation among diatoms could be a propensity for additional stable genome duplications. Across eukaryotic taxa, genome size is directly correlated to cell size and inversely correlated to physiological rates. Differences in relative genome size, cell size, and acclimated growth rates were analyzed in isolates of the diatom Ditylum brightwellii. Ditylum brightwellii consists of two main populations with identical 18s rDNA sequences; one population is distributed globally at temperate latitudes and the second appears to be localized to the Pacific Northwest coast of the USA. These two populations co-occur within the Puget Sound estuary of WA, USA, although their peak abundances differ depending on local conditions. Results All isolates from the more regionally-localized population (population 2) possessed 1.94 ± 0.74 times the amount of DNA, grew more slowly, and were generally larger than isolates from the more globally distributed population (population 1). The ITS1 sequences, cell sizes, and genome sizes of isolates from New Zealand were the same as population 1 isolates from Puget Sound, but their growth rates were within the range of the slower-growing population 2 isolates. Importantly, the observed genome size difference between isolates from the two populations was stable regardless of time in culture or the changes in cell size that accompany the diatom life history. Conclusions The observed two-fold difference in genome size between the D. brightwellii populations suggests that whole genome duplication occurred within cells of population 1 ultimately giving rise to population 2 cells. The apparent regional localization of population 2 is consistent with a recent divergence between the populations, which are likely cryptic species. Genome size variation is known to occur in other diatom genera; we hypothesize that genome duplication may be an active and important mechanism of genetic and physiological diversification and speciation in diatoms.

Published
2010
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