301
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Hu SK, Liu Z, Alexander H, Campbell V, Connell PE, Dyhrman ST, Heidelberg KB, Caron DA. Shifting metabolic priorities among key protistan taxa within and below the euphotic zone. Environ Microbiol 2018; 20:2865-2879. [PMID: 29708635 DOI: 10.1111/1462-2920.14259] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 12/12/2022]
Abstract
A metatranscriptome study targeting the protistan community was conducted off the coast of Southern California, at the San Pedro Ocean Time-series station at the surface, 150 m (oxycline), and 890 m to link putative metabolic patterns to distinct protistan lineages. Comparison of relative transcript abundances revealed depth-related shifts in the nutritional modes of key taxonomic groups. Eukaryotic gene expression in the sunlit surface environment was dominated by phototrophs, such as diatoms and chlorophytes, and high abundances of transcripts associated with synthesis pathways (e.g., photosynthesis, carbon fixation, fatty acid synthesis). Sub-euphotic depths (150 and 890 m) exhibited strong contributions from dinoflagellates and ciliates, and were characterized by transcripts relating to digestion or intracellular nutrient recycling (e.g., breakdown of fatty acids and V-type ATPases). These transcriptional patterns underlie the distinct nutritional modes of ecologically important protistan lineages that drive marine food webs, and provide a framework to investigate trophic dynamics across diverse protistan communities.
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Affiliation(s)
- Sarah K Hu
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Zhenfeng Liu
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Harriet Alexander
- Department of Population Health and Reproduction, University of California Davis, Davis, CA, USA
| | - Victoria Campbell
- Division Allergy and Infectious Diseases, UW Medicine, Seattle, WA, USA
| | - Paige E Connell
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Sonya T Dyhrman
- Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - Karla B Heidelberg
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - David A Caron
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
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302
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Choi CJ, Bachy C, Jaeger GS, Poirier C, Sudek L, Sarma VVSS, Mahadevan A, Giovannoni SJ, Worden AZ. Newly discovered deep-branching marine plastid lineages are numerically rare but globally distributed. Curr Biol 2018; 27:R15-R16. [PMID: 28073013 DOI: 10.1016/j.cub.2016.11.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Ocean surface warming is resulting in an expansion of stratified, low-nutrient environments, a process referred to as ocean desertification [1]. A challenge for assessing the impact of these changes is the lack of robust baseline information on the biological communities that carry out marine photosynthesis. Phytoplankton perform half of global biological CO2 uptake, fuel marine food chains, and include diverse eukaryotic algae that have photosynthetic organelles (plastids) acquired through multiple evolutionary events [1-3]. While amassing data from ocean ecosystems for the Baselines Initiative (6,177 near full-length 16S rRNA gene sequences and 9.4 million high-quality 16S V1-V2 amplicons) we identified two deep-branching plastid lineages based on 16S rRNA gene data. The two lineages have global distributions, but do not correspond to known phytoplankton. How the newly discovered phytoplankton lineages contribute to food chains and vertical carbon export to the deep sea remains unknown, but their prevalence in expanding, low nutrient surface waters suggests they will have a role in future oceans.
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Affiliation(s)
- Chang Jae Choi
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA
| | - Charles Bachy
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA
| | | | - Camille Poirier
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA
| | - Lisa Sudek
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA
| | - V V S S Sarma
- National Institute of Oceanography, Visakhapatnam, India
| | - Amala Mahadevan
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | | | - Alexandra Z Worden
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA; Integrated Microbial Biodiversity Program, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada.
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303
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Zhang C, Dang H, Azam F, Benner R, Legendre L, Passow U, Polimene L, Robinson C, Suttle CA, Jiao N. Evolving paradigms in biological carbon cycling in the ocean. Natl Sci Rev 2018. [DOI: 10.1093/nsr/nwy074] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
ABSTRACT
Carbon is a keystone element in global biogeochemical cycles. It plays a fundamental role in biotic and abiotic processes in the ocean, which intertwine to mediate the chemistry and redox status of carbon in the ocean and the atmosphere. The interactions between abiotic and biogenic carbon (e.g. CO2, CaCO3, organic matter) in the ocean are complex, and there is a half-century-old enigma about the existence of a huge reservoir of recalcitrant dissolved organic carbon (RDOC) that equates to the magnitude of the pool of atmospheric CO2. The concepts of the biological carbon pump (BCP) and the microbial loop (ML) shaped our understanding of the marine carbon cycle. The more recent concept of the microbial carbon pump (MCP), which is closely connected to those of the BCP and the ML, explicitly considers the significance of the ocean's RDOC reservoir and provides a mechanistic framework for the exploration of its formation and persistence. Understanding of the MCP has benefited from advanced ‘omics’ and novel research in biological oceanography and microbial biogeochemistry. The need to predict the ocean's response to climate change makes an integrative understanding of the BCP, ML and MCP a high priority. In this review, we summarize and discuss progress since the proposal of the MCP in 2010 and formulate research questions for the future.
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Affiliation(s)
- Chuanlun Zhang
- Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hongyue Dang
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Farooq Azam
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Ronald Benner
- Department of Biological Sciences and School of the Earth, Ocean and Environment, University of South Carolina, Columbia, SC 29208, USA
| | - Louis Legendre
- Sorbonne Université, Laboratoire d’Océanographie de Villefranche, LOV, 06230 Villefranche-sur-Mer, France
| | - Uta Passow
- Marine Science Institute, University of California Santa Barbara, CA 93106, USA
| | - Luca Polimene
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK
| | - Carol Robinson
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Curtis A Suttle
- Departments of Earth, Ocean and Atmospheric Sciences, Botany, and Microbiology and Immunology, and the Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
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304
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305
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Waller RF, Cleves PA, Rubio-Brotons M, Woods A, Bender SJ, Edgcomb V, Gann ER, Jones AC, Teytelman L, von Dassow P, Wilhelm SW, Collier JL. Strength in numbers: Collaborative science for new experimental model systems. PLoS Biol 2018; 16:e2006333. [PMID: 29965960 PMCID: PMC6044537 DOI: 10.1371/journal.pbio.2006333] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/13/2018] [Indexed: 11/18/2022] Open
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.
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Affiliation(s)
- Ross F. Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (RFW); (JLC)
| | - Phillip A. Cleves
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Maria Rubio-Brotons
- Institut de Biologia Evolutiva, Spanish National Research Council (CSIC)–Universitat Pompeu Fabra, Barcelona, Catalonia, Spain
| | - April Woods
- Environmental Biotechnology Lab, Moss Landing Marine Laboratories, California, United States of America
| | - Sara J. Bender
- Gordon and Betty Moore Foundation, Palo Alto, California, United States of America
| | - Virginia Edgcomb
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America
| | - Eric R. Gann
- Department of Microbiology, The University of Tennessee, Knoxville, Tennessee, United States of America
| | - Adam C. Jones
- Gordon and Betty Moore Foundation, Palo Alto, California, United States of America
| | | | - Peter von Dassow
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Instituto Milenio de Oceanografía, Concepción, Chile
| | - Steven W. Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, Tennessee, United States of America
| | - Jackie L. Collier
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail: (RFW); (JLC)
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306
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Boscaro V, Santoferrara LF, Zhang Q, Gentekaki E, Syberg-Olsen MJ, Del Campo J, Keeling PJ. EukRef-Ciliophora: a manually curated, phylogeny-based database of small subunit rRNA gene sequences of ciliates. Environ Microbiol 2018; 20:2218-2230. [PMID: 29727060 DOI: 10.1111/1462-2920.14264] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/13/2018] [Accepted: 04/27/2018] [Indexed: 01/01/2023]
Abstract
High-throughput sequencing (HTS) surveys, among the most common approaches currently used in environmental microbiology, require reliable reference databases to be correctly interpreted. The EukRef Initiative (eukref.org) is a community effort to manually screen available small subunit (SSU) rRNA gene sequences and produce a public, high-quality and informative framework of phylogeny-based taxonomic annotations. In the context of EukRef, we present a database for the monophyletic phylum Ciliophora, one of the most complex, diverse and ubiquitous protist groups. We retrieved more than 11 500 sequences of ciliates present in GenBank (28% from identified isolates and 72% from environmental surveys). Our approach included the inference of phylogenetic trees for every ciliate lineage and produced the largest SSU rRNA tree of the phylum Ciliophora to date. We flagged approximately 750 chimeric or low-quality sequences, improved the classification of 70% of GenBank entries and enriched environmental and literature metadata by 30%. The performance of EukRef-Ciliophora is superior to the current SILVA database in classifying HTS reads from a global marine survey. Comprehensive outputs are publicly available to make the new tool a useful guide for non-specialists and a quick reference for experts.
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Affiliation(s)
- Vittorio Boscaro
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Luciana F Santoferrara
- Department of Marine Sciences, University of Connecticut, Stamford, CT, USA.,Department of Ecology and Evolutionary Biology, University of Connecticut, Stamford, CT, USA
| | - Qianqian Zhang
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Eleni Gentekaki
- School of Science, Mae Fah Luang University, Chiang Rai, Thailand
| | | | - Javier Del Campo
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
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307
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Li F, Xie W, Yuan Q, Luo H, Li P, Chen T, Zhao X, Wang Z, Ma H. Genome-scale metabolic model analysis indicates low energy production efficiency in marine ammonia-oxidizing archaea. AMB Express 2018; 8:106. [PMID: 29946801 PMCID: PMC6038301 DOI: 10.1186/s13568-018-0635-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/18/2018] [Indexed: 12/02/2022] Open
Abstract
Marine ammonia-oxidizing archaea (AOA) play an important role in the global nitrogen cycle by obtaining energy for biomass production from CO2 via oxidation of ammonium. The isolation of Candidatus “Nitrosopumilus maritimus” strain SCM1, which represents the globally distributed AOA in the ocean, provided an opportunity for uncovering the contributions of those AOA to carbon and nitrogen cycles in ocean. Although several ammonia oxidation pathways have been proposed for SCM1, little is known about its ATP production efficiency. Here, based on the published genome of Nitrosopumilus maritimus SCM1, a genome-scale metabolic model named NmrFL413 was reconstructed. Based on the model NmrFL413, the estimated ATP/NH4+ yield (0.149–0.276 ATP/NH4+) is tenfold lower than the calculated theoretical yield of the proposed ammonia oxidation pathways in marine AOA (1.5–1.75 ATP/NH4+), indicating a low energy production efficiency of SCM1. Our model also suggested the minor contribution of marine AOA to carbon cycle comparing with their significant contribution to nitrogen cycle in the ocean.
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308
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Guo J, Wilken S, Jimenez V, Choi CJ, Ansong C, Dannebaum R, Sudek L, Milner DS, Bachy C, Reistetter EN, Elrod VA, Klimov D, Purvine SO, Wei CL, Kunde-Ramamoorthy G, Richards TA, Goodenough U, Smith RD, Callister SJ, Worden AZ. Specialized proteomic responses and an ancient photoprotection mechanism sustain marine green algal growth during phosphate limitation. Nat Microbiol 2018; 3:781-790. [PMID: 29946165 DOI: 10.1038/s41564-018-0178-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 05/16/2018] [Indexed: 01/05/2023]
Abstract
Marine algae perform approximately half of global carbon fixation, but their growth is often limited by the availability of phosphate or other nutrients1,2. As oceans warm, the area of phosphate-limited surface waters is predicted to increase, resulting in ocean desertification3,4. Understanding the responses of key eukaryotic phytoplankton to nutrient limitation is therefore critical5,6. We used advanced photo-bioreactors to investigate how the widespread marine green alga Micromonas commoda grows under transitions from replete nutrients to chronic phosphate limitation and subsequent relief, analysing photosystem changes and broad cellular responses using proteomics, transcriptomics and biophysical measurements. We find that physiological and protein expression responses previously attributed to stress are critical to supporting stable exponential growth when phosphate is limiting. Unexpectedly, the abundance of most proteins involved in light harvesting does not change, but an ancient light-harvesting-related protein, LHCSR, is induced and dissipates damaging excess absorbed light as heat throughout phosphate limitation. Concurrently, a suite of uncharacterized proteins with narrow phylogenetic distributions increase multifold. Notably, of the proteins that exhibit significant changes, 70% are not differentially expressed at the mRNA transcript level, highlighting the importance of post-transcriptional processes in microbial eukaryotes. Nevertheless, transcript-protein pairs with concordant changes were identified that will enable more robust interpretation of eukaryotic phytoplankton responses in the field from metatranscriptomic studies. Our results show that P-limited Micromonas responds quickly to a fresh pulse of phosphate by rapidly increasing replication, and that the protein network associated with this ability is composed of both conserved and phylogenetically recent proteome systems that promote dynamic phosphate homeostasis. That an ancient mechanism for mitigating light stress is central to sustaining growth during extended phosphate limitation highlights the possibility of interactive effects arising from combined stressors under ocean change, which could reduce the efficacy of algal strategies for optimizing marine photosynthesis.
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Affiliation(s)
- Jian Guo
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - Susanne Wilken
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA.,Department of Freshwater and Marine Ecology, University of Amsterdam, Amsterdam, the Netherlands
| | - Valeria Jimenez
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA.,Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Chang Jae Choi
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - Charles Ansong
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - Richard Dannebaum
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA.,Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, CA, USA
| | - Lisa Sudek
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | | | - Charles Bachy
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | | | | | - Denis Klimov
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | | | - Chia-Lin Wei
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, CA, USA.,The Jackson Laboratory, Farmington, CT, USA
| | - Govindarajan Kunde-Ramamoorthy
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, CA, USA.,The Jackson Laboratory, Farmington, CT, USA
| | | | | | | | | | - Alexandra Z Worden
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA. .,Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, CA, USA.
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309
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Distinct patterns and processes of abundant and rare eukaryotic plankton communities following a reservoir cyanobacterial bloom. ISME JOURNAL 2018; 12:2263-2277. [PMID: 29899512 PMCID: PMC6092360 DOI: 10.1038/s41396-018-0159-0] [Citation(s) in RCA: 297] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 04/29/2018] [Accepted: 05/01/2018] [Indexed: 11/08/2022]
Abstract
Plankton communities normally consist of few abundant and many rare species, yet little is known about the ecological role of rare planktonic eukaryotes. Here we used a 18S ribosomal DNA sequencing approach to investigate the dynamics of rare planktonic eukaryotes, and to explore the co-occurrence patterns of abundant and rare eukaryotic plankton in a subtropical reservoir following a cyanobacterial bloom event. Our results showed that the bloom event significantly altered the eukaryotic plankton community composition and rare plankton diversity without affecting the diversity of abundant plankton. The similarities of both abundant and rare eukaryotic plankton subcommunities significantly declined with the increase in time-lag, but stronger temporal turnover was observed in rare taxa. Further, species turnover of both subcommunities explained a higher percentage of the community variation than species richness. Both deterministic and stochastic processes significantly influenced eukaryotic plankton community assembly, and the stochastic pattern (e.g., ecological drift) was particularly pronounced for rare taxa. Co-occurrence network analysis revealed that keystone taxa mainly belonged to rare species, which may play fundamental roles in network persistence. Importantly, covariations between rare and non-rare taxa were predominantly positive, implying multispecies cooperation might contribute to the stability and resilience of the microbial community. Overall, these findings expand current understanding of the ecological mechanisms and microbial interactions underlying plankton dynamics in changing aquatic ecosystems.
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310
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Farming, slaving and enslavement: histories of endosymbioses during kinetoplastid evolution. Parasitology 2018; 145:1311-1323. [PMID: 29895336 DOI: 10.1017/s0031182018000781] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Parasitic trypanosomatids diverged from free-living kinetoplastid ancestors several hundred million years ago. These parasites are relatively well known, due in part to several unusual cell biological and molecular traits and in part to the significance of a few - pathogenic Leishmania and Trypanosoma species - as aetiological agents of serious neglected tropical diseases. However, the majority of trypanosomatid biodiversity is represented by osmotrophic monoxenous parasites of insects. In two lineages, novymonads and strigomonads, osmotrophic lifestyles are supported by cytoplasmic endosymbionts, providing hosts with macromolecular precursors and vitamins. Here we discuss the two independent origins of endosymbiosis within trypanosomatids and subsequently different evolutionary trajectories that see entrainment vs tolerance of symbiont cell divisions cycles within those of the host. With the potential to inform on the transition to obligate parasitism in the trypanosomatids, interest in the biology and ecology of free-living, phagotrophic kinetoplastids is beginning to enjoy a renaissance. Thus, we take the opportunity to additionally consider the wider relevance of endosymbiosis during kinetoplastid evolution, including the indulged lifestyle and reductive evolution of basal kinetoplastid Perkinsela.
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311
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Zhou J, Richlen ML, Sehein TR, Kulis DM, Anderson DM, Cai Z. Microbial Community Structure and Associations During a Marine Dinoflagellate Bloom. Front Microbiol 2018; 9:1201. [PMID: 29928265 PMCID: PMC5998739 DOI: 10.3389/fmicb.2018.01201] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 05/16/2018] [Indexed: 11/13/2022] Open
Abstract
Interactions between microorganisms and algae during bloom events significantly impacts their physiology, alters ambient chemistry, and shapes ecosystem diversity. The potential role these interactions have in bloom development and decline are also of particular interest given the ecosystem impacts of algal blooms. We hypothesized that microbial community structure and succession is linked to specific bloom stages, and reflects complex interactions among taxa comprising the phycosphere environment. This investigation used pyrosequencing and correlation approaches to assess patterns and associations among bacteria, archaea, and microeukaryotes during a spring bloom of the dinoflagellate Alexandrium catenella. Within the bacterial community, Gammaproteobacteria and Bacteroidetes were predominant during the initial bloom stage, while Alphaproteobacteria, Cyanobacteria, and Actinobacteria were the most abundant taxa present during bloom onset and termination. In the archaea biosphere, methanogenic members were present during the early bloom period while the majority of species identified in the late bloom stage were ammonia-oxidizing archaea and Halobacteriales. Dinoflagellates were the major eukaryotic group present during most stages of the bloom, whereas a mixed assemblage comprising diatoms, green-algae, rotifera, and other microzooplankton were present during bloom termination. Temperature and salinity were key environmental factors associated with changes in bacterial and archaeal community structure, respectively, whereas inorganic nitrogen and inorganic phosphate were associated with eukaryotic variation. The relative contribution of environmental parameters measured during the bloom to variability among samples was 35.3%. Interaction analysis showed that Maxillopoda, Spirotrichea, Dinoflagellata, and Halobacteria were keystone taxa within the positive-correlation network, while Halobacteria, Dictyochophyceae, Mamiellophyceae, and Gammaproteobacteria were the main contributors to the negative-correlation network. The positive and negative relationships were the primary drivers of mutualist and competitive interactions that impacted algal bloom fate, respectively. Functional predictions showed that blooms enhance microbial carbohydrate and energy metabolism, and alter the sulfur cycle. Our results suggest that microbial community structure is strongly linked to bloom progression, although specific drivers of community interactions and responses are not well understood. The importance of considering biotic interactions (e.g., competition, symbiosis, and predation) when investigating the link between microbial ecological behavior and an algal bloom's trajectory is also highlighted.
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Affiliation(s)
- Jin Zhou
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
| | - Mindy L. Richlen
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Taylor R. Sehein
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - David M. Kulis
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Donald M. Anderson
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Zhonghua Cai
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
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312
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Boyd PW, Collins S, Dupont S, Fabricius K, Gattuso JP, Havenhand J, Hutchins DA, Riebesell U, Rintoul MS, Vichi M, Biswas H, Ciotti A, Gao K, Gehlen M, Hurd CL, Kurihara H, McGraw CM, Navarro JM, Nilsson GE, Passow U, Pörtner HO. Experimental strategies to assess the biological ramifications of multiple drivers of global ocean change-A review. GLOBAL CHANGE BIOLOGY 2018; 24:2239-2261. [PMID: 29476630 DOI: 10.1111/gcb.14102] [Citation(s) in RCA: 153] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/11/2017] [Accepted: 01/02/2018] [Indexed: 05/19/2023]
Abstract
Marine life is controlled by multiple physical and chemical drivers and by diverse ecological processes. Many of these oceanic properties are being altered by climate change and other anthropogenic pressures. Hence, identifying the influences of multifaceted ocean change, from local to global scales, is a complex task. To guide policy-making and make projections of the future of the marine biosphere, it is essential to understand biological responses at physiological, evolutionary and ecological levels. Here, we contrast and compare different approaches to multiple driver experiments that aim to elucidate biological responses to a complex matrix of ocean global change. We present the benefits and the challenges of each approach with a focus on marine research, and guidelines to navigate through these different categories to help identify strategies that might best address research questions in fundamental physiology, experimental evolutionary biology and community ecology. Our review reveals that the field of multiple driver research is being pulled in complementary directions: the need for reductionist approaches to obtain process-oriented, mechanistic understanding and a requirement to quantify responses to projected future scenarios of ocean change. We conclude the review with recommendations on how best to align different experimental approaches to contribute fundamental information needed for science-based policy formulation.
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Affiliation(s)
- Philip W Boyd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tas., Australia
| | - Sinead Collins
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Sam Dupont
- Department of Biological & Environmental Sciences - Kristineberg, University of Gothenburg, Gothenburg, Sweden
| | | | - Jean-Pierre Gattuso
- Observatoire Océanologique, Laboratoire d'Océanographie, CNRS-UPMC, Villefranche-Sur-Mer, France
| | - Jonathan Havenhand
- Department of Marine Sciences - Tjärnö, University of Gothenburg, Gothenburg, Sweden
| | | | - Ulf Riebesell
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Max S Rintoul
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tas., Australia
| | - Marcello Vichi
- Marine Research Institute and Department of Oceanography, University of Cape Town, Cape Town, South Africa
| | | | - Aurea Ciotti
- Centro de Biologia Marinha, Universidade de São Paulo, Sao Sebastiao, São Paulo, Brazil
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, China
| | - Marion Gehlen
- Laboratoire des Sciences du Climat et de l'Environnement, Gif-Sur-Yvette, France
| | - Catriona L Hurd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., Australia
| | | | - Christina M McGraw
- Department of Chemistry, NIWA/University of Otago Research Centre for Oceanography, University of Otago, Dunedin, New Zealand
| | - Jorge M Navarro
- Instituto de Ciencias Marinas y Limnológicas, Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Universidad Austral de Chile, Valdivia, Chile
| | | | - Uta Passow
- Marine Science Institute, UC Santa Barbara, Santa Barbara, CA, USA
| | - Hans-Otto Pörtner
- Helmholtz Centre for Polar and Marine Research, Alfred Wegener Institute, Bremerhaven, Germany
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313
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Jones AC, Hambright KD, Caron DA. Ecological Patterns Among Bacteria and Microbial Eukaryotes Derived from Network Analyses in a Low-Salinity Lake. MICROBIAL ECOLOGY 2018; 75:917-929. [PMID: 29110066 DOI: 10.1007/s00248-017-1087-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 10/09/2017] [Indexed: 06/07/2023]
Abstract
Microbial communities are comprised of complex assemblages of highly interactive taxa. We employed network analyses to identify and describe microbial interactions and co-occurrence patterns between microbial eukaryotes and bacteria at two locations within a low salinity (0.5-3.5 ppt) lake over an annual cycle. We previously documented that the microbial diversity and community composition within Lake Texoma, southwest USA, were significantly affected by both seasonal forces and a site-specific bloom of the harmful alga, Prymnesium parvum. We used network analyses to answer ecological questions involving both the bacterial and microbial eukaryotic datasets and to infer ecological relationships within the microbial communities. Patterns of connectivity at both locations reflected the seasonality of the lake including a large rain disturbance in May, while a comparison of the communities between locations revealed a localized response to the algal bloom. A network built from shared nodes (microbial operational taxonomic units and environmental variables) and correlations identified conserved associations at both locations within the lake. Using network analyses, we were able to detect disturbance events, characterize the ecological extent of a harmful algal bloom, and infer ecological relationships not apparent from diversity statistics alone.
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Affiliation(s)
- Adriane Clark Jones
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089-0371, USA.
- Department of Biological Sciences, Mount Saint Mary's University, Los Angeles, CA, 90049, USA.
| | - K David Hambright
- Program in Ecology and Evolutionary Biology, Department of Biology, University of Oklahoma, Norman, OK, 73019, USA
| | - David A Caron
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089-0371, USA
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314
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Nabais C, Pereira SG, Bettencourt-Dias M. Noncanonical Biogenesis of Centrioles and Basal Bodies. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2018; 82:123-135. [PMID: 29686032 DOI: 10.1101/sqb.2017.82.034694] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Centrioles and basal bodies (CBBs) organize centrosomes and cilia within eukaryotic cells. These organelles are composed of microtubules and hundreds of proteins performing multiple functions such as signaling, cytoskeleton remodeling, and cell motility. The CBB is present in all branches of the eukaryotic tree of life and, despite its ultrastructural and protein conservation, there is diversity in its function, occurrence (i.e., presence/absence), and modes of biogenesis across species. In this review, we provide an overview of the multiple pathways through which CBBs are formed in nature, with a special focus on the less studied, noncanonical ways. Despite the differences among each mechanism herein presented, we highlighted some of their common principles. These principles, governing different steps of biogenesis, ensure that CBBs may perform a multitude of functions in a huge diversity of organisms but yet retained their robustness in structure throughout evolution.
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Affiliation(s)
- Catarina Nabais
- Cell Cycle Regulation Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal
| | - Sónia Gomes Pereira
- Cell Cycle Regulation Lab, Instituto Gulbenkian de Ciência (IGC), 2780-156 Oeiras, Portugal
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315
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Kraft CE, Angert ER. Competition for vitamin B1 (thiamin) structures numerous ecological interactions. QUARTERLY REVIEW OF BIOLOGY 2018; 92:151-68. [PMID: 29562121 DOI: 10.1086/692168] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Thiamin (vitamin B1) is a cofactor required for essential biochemical reactions in all living organisms, yet free thiamin is scarce in the environment. The diversity of biochemical pathways involved in the acquisition, degradation, and synthesis of thiamin indicates that organisms have evolved numerous ecological strategies for meeting this nutritional requirement. In this review we synthesize information from multiple disciplines to show how the complex biochemistry of thiamin influences ecological outcomes of interactions between organisms in environments ranging from the open ocean and the Australian outback to the gastrointestinal tract of animals. We highlight population and ecosystem responses to the availability or absence of thiamin. These include widespread mortality of fishes, birds, and mammals, as well as the thiamin-dependent regulation of ocean productivity. Overall, we portray thiamin biochemistry as the foundation for molecularly mediated ecological interactions that influence survival and abundance of a vast array of organisms.
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316
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Behringer G, Ochsenkühn MA, Fei C, Fanning J, Koester JA, Amin SA. Bacterial Communities of Diatoms Display Strong Conservation Across Strains and Time. Front Microbiol 2018; 9:659. [PMID: 29681892 PMCID: PMC5897529 DOI: 10.3389/fmicb.2018.00659] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 03/21/2018] [Indexed: 11/13/2022] Open
Abstract
Interactions between phytoplankton and bacteria play important roles in shaping the microenvironment surrounding these organisms and in turn influence global biogeochemical cycles. This microenvironment, known as the phycosphere, is presumed to shape the bacterial diversity around phytoplankton and thus stimulate a diverse array of interactions between both groups. Although many studies have attempted to characterize bacterial communities that associate and interact with phytoplankton, bias in bacterial cultivation and consistency and persistence of bacterial communities across phytoplankton isolates likely impede the understanding of these microbial associations. Here, we isolate four strains of the diatom Asterionellopsis glacialis and three strains of the diatom Nitzschia longissima and show through metabarcoding of the bacterial 16S rDNA gene that though each species possesses a unique bacterial community, the bacterial composition across strains from the same species are highly conserved at the genus level. Cultivation of all seven strains in the laboratory for longer than 1 year resulted in only small changes to the bacterial composition, suggesting that despite strong pressures from laboratory culturing conditions associations between these diatoms and their bacterial communities are robust. Specific operational taxonomic units (OTUs) belonging to the Roseobacter-clade appear to be conserved across all strains and time, suggesting their importance to diatoms. In addition, we isolate a range of cultivable bacteria from one of these cultures, A. glacialis strain A3, including several strains of Shimia marina and Nautella sp. that appear closely related to OTUs conserved across all strains and times. Coculturing of A3 with some of its cultivable bacteria as well as other diatom-associated bacteria shows a wide range of responses that include enhancing diatom growth. Cumulatively, these findings suggest that phytoplankton possess unique microbiomes that are consistent across strains and temporal scales.
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Affiliation(s)
- Gregory Behringer
- Marine Microbial Ecology Lab, Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Michael A. Ochsenkühn
- Marine Microbial Ecology Lab, Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Cong Fei
- Marine Microbial Ecology Lab, Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- College of Resources and Environmental Science, Nanjing Agriculture University, Nanjing, China
| | - Jhamal Fanning
- Marine Microbial Ecology Lab, Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Julie A. Koester
- Department of Biology and Marine Biology, University of North Carolina at Wilmington, Wilmington, NC, United States
| | - Shady A. Amin
- Marine Microbial Ecology Lab, Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
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317
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Heiss AA, Kolisko M, Ekelund F, Brown MW, Roger AJ, Simpson AGB. Combined morphological and phylogenomic re-examination of malawimonads, a critical taxon for inferring the evolutionary history of eukaryotes. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171707. [PMID: 29765641 PMCID: PMC5936906 DOI: 10.1098/rsos.171707] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 03/06/2018] [Indexed: 05/16/2023]
Abstract
Modern syntheses of eukaryote diversity assign almost all taxa to one of three groups: Amorphea, Diaphoretickes and Excavata (comprising Discoba and Metamonada). The most glaring exception is Malawimonadidae, a group of small heterotrophic flagellates that resemble Excavata by morphology, but branch with Amorphea in most phylogenomic analyses. However, just one malawimonad, Malawimonas jakobiformis, has been studied with both morphological and molecular-phylogenetic approaches, raising the spectre of interpretation errors and phylogenetic artefacts from low taxon sampling. We report a morphological and phylogenomic study of a new deep-branching malawimonad, Gefionella okellyi n. gen. n. sp. Electron microscopy revealed all canonical features of 'typical excavates', including flagellar vanes (as an opposed pair, unlike M. jakobiformis but like many metamonads) and a composite fibre. Initial phylogenomic analyses grouped malawimonads with the Amorphea-related orphan lineage Collodictyon, separate from a Metamonada+Discoba clade. However, support for this topology weakened when more sophisticated evolutionary models were used, and/or fast-evolving sites and long-branching taxa (FS/LB) were excluded. Analyses of '-FS/LB' datasets instead suggested a relationship between malawimonads and metamonads. The 'malawimonad+metamonad signal' in morphological and molecular data argues against a strict Metamonada+Discoba clade (i.e. the predominant concept of Excavata). A Metamonad+Discoba clade should therefore not be assumed when inferring deep-level evolutionary history in eukaryotes.
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Affiliation(s)
- Aaron A. Heiss
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Martin Kolisko
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Fleming Ekelund
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Matthew W. Brown
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Andrew J. Roger
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Alastair G. B. Simpson
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
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318
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Berdjeb L, Parada A, Needham DM, Fuhrman JA. Short-term dynamics and interactions of marine protist communities during the spring-summer transition. ISME JOURNAL 2018; 12:1907-1917. [PMID: 29599520 DOI: 10.1038/s41396-018-0097-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 02/15/2018] [Accepted: 02/26/2018] [Indexed: 11/09/2022]
Abstract
We examined the short-term variability, by daily to weekly sampling, of protist assemblages from March to July in surface water of the San Pedro Ocean Time-series station (eastern North Pacific), by V4 Illumina sequencing of the 18S rRNA gene. The sampling period encompassed a spring bloom followed by progression to summer conditions. Several protistan taxa displayed sharp increases and declines, with whole community Bray-Curtis dissimilarities of adjacent days being 66% in March and 40% in May. High initial abundance of parasitic Cercozoa Cryothecomonas longipes and Protaspis grandis coincided with a precipitous decline of blooming Pseudo-nitzschia diatoms, possibly suggesting their massive infection by these parasites; these cercozoans were hardly detectable afterwards. Canonical correspondence analysis indicated a limited predictability of community variability from environmental factors. This indicates that other factors are relevant in explaining changes in protist community composition at short temporal scales, such as interspecific relationships, stochastic processes, mixing with adjacent water, or advection of patches with different protist communities. Association network analysis revealed that interactions between the many parasitic OTUs and other taxa were overwhelmingly positive and suggest that although sometimes parasites may cause a crash of host populations, they may often follow their hosts and do not regularly cause enough mortality to potentially create negative correlations at the daily to weekly time scales we studied.
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Affiliation(s)
- Lyria Berdjeb
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Alma Parada
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - David M Needham
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Jed A Fuhrman
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
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319
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Wang Y, Sen B, He Y, Xie N, Wang G. Spatiotemporal Distribution and Assemblages of Planktonic Fungi in the Coastal Waters of the Bohai Sea. Front Microbiol 2018; 9:584. [PMID: 29643845 PMCID: PMC5882831 DOI: 10.3389/fmicb.2018.00584] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 03/14/2018] [Indexed: 11/13/2022] Open
Abstract
Fungi play a critical role in the nutrient cycling and ecological function in terrestrial and freshwater ecosystems. Yet, many ecological aspects of their counterparts in coastal ecosystems remain largely elusive. Using high-throughput sequencing, quantitative PCR, and environmental data analyses, we studied the spatiotemporal changes in the abundance and diversity of planktonic fungi and their abiotic and biotic interactions in the coastal waters of three transects along the Bohai Sea. A total of 4362 ITS OTUs were identified and more than 60% of which were unclassified Fungi. Of the classified OTUs three major fungal phyla, Ascomycota, Basidiomycota, and Chytridiomycota were predominant with episodic low dominance phyla Cryptomycota and Mucoromycota (Mortierellales). The estimated average Fungi-specific 18S rRNA gene qPCR abundances varied within 4.28 × 106 and 1.13 × 107copies/L with significantly (P < 0.05) different abundances among the transects suggesting potential influence of the different riverine inputs. The spatiotemporal changes in the OTU abundance of Ascomycota and Basidiomycota phyla coincided significantly (P < 0.05) with nutrients traced to riverine inputs and phytoplankton detritus. Among the eight major fungal orders, the abundance of Hypocreales varied significantly (P < 0.01) across months while Capnodiales, Pleosporales, Eurotiales, and Sporidiobolales varied significantly (P < 0.05) across transects. In addition, our results likely suggest a tripartite interaction model for the association within members of Cryptomycota (hyperparasites), Chytridiomycota (both parasites and saprotrophs), and phytoplankton in the coastal waters. The fungal network featured several hubs and keystone OTUs besides the display of cooperative and competitive relationship within OTUs. These results support the notion that planktonic fungi, hitherto mostly undescribed, play diverse ecological roles in marine habitats and further outline niche processes, tripartite and co-occurrence interaction as the major drivers of their community structure and spatiotemporal distribution in the coastal water column.
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Affiliation(s)
- Yaqiong Wang
- Center for Marine Environmental Ecology, School of Environment Science and Engineering, Tianjin University, Tianjin, China
- School of Ecology, Environment and Resources, Qinghai University for Nationalities, Xining, China
| | - Biswarup Sen
- Center for Marine Environmental Ecology, School of Environment Science and Engineering, Tianjin University, Tianjin, China
| | - Yaodong He
- Center for Marine Environmental Ecology, School of Environment Science and Engineering, Tianjin University, Tianjin, China
| | - Ningdong Xie
- Center for Marine Environmental Ecology, School of Environment Science and Engineering, Tianjin University, Tianjin, China
- Duke Marine Laboratory, Nicholas School of the Environment, Duke University, Durham, NC, United States
| | - Guangyi Wang
- Center for Marine Environmental Ecology, School of Environment Science and Engineering, Tianjin University, Tianjin, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
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320
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Singer D, Kosakyan A, Seppey CVW, Pillonel A, Fernández LD, Fontaneto D, Mitchell EAD, Lara E. Environmental filtering and phylogenetic clustering correlate with the distribution patterns of cryptic protist species. Ecology 2018; 99:904-914. [DOI: 10.1002/ecy.2161] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/27/2017] [Accepted: 01/08/2018] [Indexed: 12/12/2022]
Affiliation(s)
- David Singer
- Laboratory of Soil Biodiversity; Institute of Biology; University of Neuchâtel; Rue Emile-Argand 11 CH-2000 Neuchâtel Switzerland
| | - Anush Kosakyan
- Laboratory of Soil Biodiversity; Institute of Biology; University of Neuchâtel; Rue Emile-Argand 11 CH-2000 Neuchâtel Switzerland
- Department of Zoology; Institute of Biosciences; University of São Paulo; São Paulo 05508 Brazil
- Institute of Parasitology, Biology Centre; Czech Academy of Sciences; Branisovska 31 České Budějovice 37005 Czech Republic
| | - Christophe V. W. Seppey
- Laboratory of Soil Biodiversity; Institute of Biology; University of Neuchâtel; Rue Emile-Argand 11 CH-2000 Neuchâtel Switzerland
- Microorganisms and Plants Group; Department of Arctic and Marine Biology; Faculty of Biosciences, Fisheries and Economics; University of Tromsø; Framstredet 39 9037 Tromsø Norway
| | - Amandine Pillonel
- Laboratory of Soil Biodiversity; Institute of Biology; University of Neuchâtel; Rue Emile-Argand 11 CH-2000 Neuchâtel Switzerland
| | - Leonardo D. Fernández
- Laboratory of Soil Biodiversity; Institute of Biology; University of Neuchâtel; Rue Emile-Argand 11 CH-2000 Neuchâtel Switzerland
- Laboratorio de Ecología Evolutiva y Filoinformática; Departamento de Zoología; Facultad de Ciencias Naturales y Oceanográficas; Universidad de Concepción; Barrio Universitario s/n, Casilla 160-C Concepción Chile
- Centro de Investigación en Recursos Naturales y Sustentabilidad (CIRENYS); Universidad Bernardo O'Higgins; Avenida Viel 1497 Santiago Chile
| | - Diego Fontaneto
- National Research Council of Italy; Institute of Ecosystem Study; 28922 Verbania Pallanza Italy
| | - Edward A. D. Mitchell
- Laboratory of Soil Biodiversity; Institute of Biology; University of Neuchâtel; Rue Emile-Argand 11 CH-2000 Neuchâtel Switzerland
- Jardin Botanique de Neuchâtel; Chemin du Perthuis-du-Sault 58 CH-2000 Neuchâtel Switzerland
| | - Enrique Lara
- Laboratory of Soil Biodiversity; Institute of Biology; University of Neuchâtel; Rue Emile-Argand 11 CH-2000 Neuchâtel Switzerland
- Real Jardín Botánico; CSIC; Plaza Murillo 2 ES 28014 Madrid Spain
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321
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Pita L, Rix L, Slaby BM, Franke A, Hentschel U. The sponge holobiont in a changing ocean: from microbes to ecosystems. MICROBIOME 2018; 6:46. [PMID: 29523192 PMCID: PMC5845141 DOI: 10.1186/s40168-018-0428-1] [Citation(s) in RCA: 254] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/20/2018] [Indexed: 05/04/2023]
Abstract
The recognition that all macroorganisms live in symbiotic association with microbial communities has opened up a new field in biology. Animals, plants, and algae are now considered holobionts, complex ecosystems consisting of the host, the microbiota, and the interactions among them. Accordingly, ecological concepts can be applied to understand the host-derived and microbial processes that govern the dynamics of the interactive networks within the holobiont. In marine systems, holobionts are further integrated into larger and more complex communities and ecosystems, a concept referred to as "nested ecosystems." In this review, we discuss the concept of holobionts as dynamic ecosystems that interact at multiple scales and respond to environmental change. We focus on the symbiosis of sponges with their microbial communities-a symbiosis that has resulted in one of the most diverse and complex holobionts in the marine environment. In recent years, the field of sponge microbiology has remarkably advanced in terms of curated databases, standardized protocols, and information on the functions of the microbiota. Like a Russian doll, these microbial processes are translated into sponge holobiont functions that impact the surrounding ecosystem. For example, the sponge-associated microbial metabolisms, fueled by the high filtering capacity of the sponge host, substantially affect the biogeochemical cycling of key nutrients like carbon, nitrogen, and phosphorous. Since sponge holobionts are increasingly threatened by anthropogenic stressors that jeopardize the stability of the holobiont ecosystem, we discuss the link between environmental perturbations, dysbiosis, and sponge diseases. Experimental studies suggest that the microbial community composition is tightly linked to holobiont health, but whether dysbiosis is a cause or a consequence of holobiont collapse remains unresolved. Moreover, the potential role of the microbiome in mediating the capacity for holobionts to acclimate and adapt to environmental change is unknown. Future studies should aim to identify the mechanisms underlying holobiont dynamics at multiple scales, from the microbiome to the ecosystem, and develop management strategies to preserve the key functions provided by the sponge holobiont in our present and future oceans.
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Affiliation(s)
- L. Pita
- RD3 Marine Microbiology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - L. Rix
- RD3 Marine Microbiology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - B. M. Slaby
- RD3 Marine Microbiology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - A. Franke
- RD3 Marine Microbiology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - U. Hentschel
- RD3 Marine Microbiology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
- Christian-Albrechts-University of Kiel (CAU), Kiel, Germany
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322
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Cryptophyta as major bacterivores in freshwater summer plankton. ISME JOURNAL 2018; 12:1668-1681. [PMID: 29463895 PMCID: PMC6018765 DOI: 10.1038/s41396-018-0057-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/20/2017] [Accepted: 11/28/2017] [Indexed: 01/05/2023]
Abstract
Small bacterivorous eukaryotes play a cardinal role in aquatic food webs and their taxonomic classification is currently a hot topic in aquatic microbial ecology. Despite increasing interest in their diversity, core questions regarding predator–prey specificity remain largely unanswered, e.g., which heterotrophic nanoflagellates (HNFs) are the main bacterivores in freshwaters and which prokaryotes support the growth of small HNFs. To answer these questions, we fed natural communities of HNFs from Římov reservoir (Czech Republic) with five different bacterial strains of the ubiquitous betaproteobacterial genera Polynucleobacter and Limnohabitans. We combined amplicon sequencing and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) targeting eukaryotic 18 S rRNA genes to track specific responses of the natural HNF community to prey amendments. While amplicon sequencing provided valuable qualitative data and a basis for designing specific probes, the number of reads was insufficient to accurately quantify certain eukaryotic groups. We also applied a double-hybridization technique that allows simultaneous phylogenetic identification of both predator and prey. Our results show that community composition of HNFs is strongly dependent upon prey type. Surprisingly, Cryptophyta were the most abundant bacterivores, although this phylum has been so far assumed to be mainly autotrophic. Moreover, the growth of a small lineage of Cryptophyta (CRY1 clade) was strongly stimulated by one Limnohabitans strain in our experiment. Thus, our study is the first report that colorless Cryptophyta are major bacterivores in summer plankton samples and can play a key role in the carbon transfer from prokaryotes to higher trophic levels.
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323
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Danovaro R, Corinaldesi C, Dell'Anno A, Rastelli E. Potential impact of global climate change on benthic deep-sea microbes. FEMS Microbiol Lett 2018; 364:4553516. [PMID: 29045616 DOI: 10.1093/femsle/fnx214] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/12/2017] [Indexed: 11/12/2022] Open
Abstract
Benthic deep-sea environments are the largest ecosystem on Earth, covering ∼65% of the Earth surface. Microbes inhabiting this huge biome at all water depths represent the most abundant biological components and a relevant portion of the biomass of the biosphere, and play a crucial role in global biogeochemical cycles. Increasing evidence suggests that global climate changes are affecting also deep-sea ecosystems, both directly (causing shifts in bottom-water temperature, oxygen concentration and pH) and indirectly (through changes in surface oceans' productivity and in the consequent export of organic matter to the seafloor). However, the responses of the benthic deep-sea biota to such shifts remain largely unknown. This applies particularly to deep-sea microbes, which include bacteria, archaea, microeukaryotes and their viruses. Understanding the potential impacts of global change on the benthic deep-sea microbial assemblages and the consequences on the functioning of the ocean interior is a priority to better forecast the potential consequences at global scale. Here we explore the potential changes in the benthic deep-sea microbiology expected in the coming decades using case studies on specific systems used as test models.
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Affiliation(s)
- Roberto Danovaro
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy.,Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Cinzia Corinaldesi
- Department of Sciences and Engineering of Materials, Environment and Urbanistics, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Antonio Dell'Anno
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Eugenio Rastelli
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy.,Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
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324
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Single-cell genomics of multiple uncultured stramenopiles reveals underestimated functional diversity across oceans. Nat Commun 2018; 9:310. [PMID: 29358710 PMCID: PMC5778133 DOI: 10.1038/s41467-017-02235-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 11/15/2017] [Indexed: 11/20/2022] Open
Abstract
Single-celled eukaryotes (protists) are critical players in global biogeochemical cycling of nutrients and energy in the oceans. While their roles as primary producers and grazers are well appreciated, other aspects of their life histories remain obscure due to challenges in culturing and sequencing their natural diversity. Here, we exploit single-cell genomics and metagenomics data from the circumglobal Tara Oceans expedition to analyze the genome content and apparent oceanic distribution of seven prevalent lineages of uncultured heterotrophic stramenopiles. Based on the available data, each sequenced genome or genotype appears to have a specific oceanic distribution, principally correlated with water temperature and depth. The genome content provides hypotheses for specialization in terms of cell motility, food spectra, and trophic stages, including the potential impact on their lifestyles of horizontal gene transfer from prokaryotes. Our results support the idea that prominent heterotrophic marine protists perform diverse functions in ocean ecology. The biology of many marine protists, such as stramenopiles, remains obscure. Here, the authors exploit single-cell genomics and metagenomics to analyze the genome content and apparent oceanic distribution of seven prevalent lineages of uncultured heterotrophic stramenopiles.
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325
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Vader A, Laughinghouse HD, Griffiths C, Jakobsen KS, Gabrielsen TM. Proton-pumping rhodopsins are abundantly expressed by microbial eukaryotes in a high-Arctic fjord. Environ Microbiol 2018; 20:890-902. [PMID: 29266690 DOI: 10.1111/1462-2920.14035] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 11/21/2017] [Accepted: 12/18/2017] [Indexed: 01/07/2023]
Abstract
Proton-pumping rhodopsins provide an alternative pathway to photosynthesis by which solar energy can enter the marine food web. Rhodopsin genes are widely found in marine bacteria, also in the Arctic, and were recently reported from several eukaryotic lineages. So far, little is known about rhodopsin expression in Arctic eukaryotes. In this study, we used metatranscriptomics and 18S rDNA tag sequencing to examine the mid-summer function and composition of marine protists (size 0.45-10 µm) in the high-Arctic Billefjorden (Spitsbergen), especially focussing on the expression of microbial proton-pumping rhodopsins. Rhodopsin transcripts were highly abundant, at a level similar to that of genes involved in photosynthesis. Phylogenetic analyses placed the environmental rhodopsins within disparate eukaryotic lineages, including dinoflagellates, stramenopiles, haptophytes and cryptophytes. Sequence comparison indicated the presence of several functional types, including xanthorhodopsins and a eukaryotic clade of proteorhodopsin. Transcripts belonging to the proteorhodopsin clade were also abundant in published metatranscriptomes from other oceanic regions, suggesting a global distribution. The diversity and abundance of rhodopsins show that these light-driven proton pumps play an important role in Arctic microbial eukaryotes. Understanding this role is imperative to predicting the future of the Arctic marine ecosystem faced by a changing light climate due to diminishing sea-ice.
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Affiliation(s)
- Anna Vader
- University Centre in Svalbard, Longyearbyen, Norway
| | | | | | - Kjetill S Jakobsen
- Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Norway
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326
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Orsi WD, Wilken S, Del Campo J, Heger T, James E, Richards TA, Keeling PJ, Worden AZ, Santoro AE. Identifying protist consumers of photosynthetic picoeukaryotes in the surface ocean using stable isotope probing. Environ Microbiol 2018; 20:815-827. [PMID: 29215213 DOI: 10.1111/1462-2920.14018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/26/2017] [Accepted: 11/26/2017] [Indexed: 11/29/2022]
Abstract
Photosynthetic picoeukaryotes contribute a significant fraction of primary production in the upper ocean. Micromonas pusilla is an ecologically relevant photosynthetic picoeukaryote, abundantly and widely distributed in marine waters. Grazing by protists may control the abundance of picoeukaryotes such as M. pusilla, but the diversity of the responsible grazers is poorly understood. To identify protists consuming photosynthetic picoeukaryotes in a productive North Pacific Ocean region, we amended seawater with living 15 N, 13 C-labelled M. pusilla cells in a 24-h replicated bottle experiment. DNA stable isotope probing, combined with high-throughput sequencing of V4 hypervariable regions from 18S rRNA gene amplicons (Tag-SIP), identified 19 operational taxonomic units (OTUs) of microbial eukaryotes that consumed M. pusilla. These OTUs were distantly related to cultured taxa within the dinoflagellates, ciliates, stramenopiles (MAST-1C and MAST-3 clades) and Telonema flagellates, thus, far known only from their environmental 18S rRNA gene sequences. Our discovery of eukaryotic prey consumption by MAST cells confirms that their trophic role in marine microbial food webs includes grazing upon picoeukaryotes. Our study provides new experimental evidence directly linking the genetic identity of diverse uncultivated microbial eukaryotes to the consumption of picoeukaryotic phytoplankton in the upper ocean.
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Affiliation(s)
- William D Orsi
- Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD 21613, USA
| | - Susanne Wilken
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA
| | - Javier Del Campo
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Thierry Heger
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Erick James
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Thomas A Richards
- Department of Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, EX4 4QD, UK
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Alyson E Santoro
- Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD 21613, USA
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327
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Zhang W, Pan Y, Yang J, Chen H, Holohan B, Vaudrey J, Lin S, McManus GB. The diversity and biogeography of abundant and rare intertidal marine microeukaryotes explained by environment and dispersal limitation. Environ Microbiol 2017; 20:462-476. [PMID: 28881067 DOI: 10.1111/1462-2920.13916] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/15/2017] [Accepted: 08/26/2017] [Indexed: 02/03/2023]
Abstract
Benthic microeukaryotes are key ecosystem drivers in marine sandy beaches, an important and dynamic environment; however, little is known about their diversity and biogeography on a large spatial scale. Here, we investigated the community composition and geographical distributions of benthic microeukaryotes using high-throughput sequencing of the 18S rRNA gene and quantified the contributions of environmental factors and spatial separation on the distribution patterns of both rare and abundant taxa. We collected 36 intertidal samples at 12 sandy beaches from four regions that spanned distances from 0.001 to 12,000 km. We found 12,890 operational taxonomic units (OTUs; 97% sequence identity level) including members of all eukaryotic super-groups and several phyla of uncertain position. Arthropoda and Diatomeae dominated the sequence reads in abundance, but Ciliophora and Discoba were the most diverse groups across all samples. About one-third of the OTUs could not be definitively classified at a similarity level of 80%, supporting the view that a large number of rare and minute marine species may have escaped previous characterization. We found generally similar geographical patterns for abundant and rare microeukaryotic sub-communities, and both showed a significant distance-decay similarity trend. Variation partitioning showed that both rare and abundant sub-communities exhibited a slightly stronger response to environmental factors than spatial (distance) factors. However, the abundant sub-community was strongly correlated with variations in spatial, environmental and sediment grain size factors (66% of variance explained), but the rare assemblage was not (16%). This suggests that different or more complex mechanisms generate and maintain diversity in the rare biosphere in this habitat.
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Affiliation(s)
- Wenjing Zhang
- State Key Laboratory of Marine Environmental Science, Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen 361005, People's Republic of China.,Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
| | - Yongbo Pan
- State Key Laboratory of Marine Environmental Science, Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen 361005, People's Republic of China
| | - Jun Yang
- Aquatic EcoHealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China
| | - Huihuang Chen
- Aquatic EcoHealth Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China
| | - Bridget Holohan
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
| | - Jamie Vaudrey
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
| | - Senjie Lin
- State Key Laboratory of Marine Environmental Science, Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen 361005, People's Republic of China.,Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
| | - George B McManus
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
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328
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Spijkerman E, Lukas M, Wacker A. Ecophysiological strategies for growth under varying light and organic carbon supply in two species of green microalgae differing in their motility. PHYTOCHEMISTRY 2017; 144:43-51. [PMID: 28881198 DOI: 10.1016/j.phytochem.2017.08.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/26/2017] [Accepted: 08/29/2017] [Indexed: 06/07/2023]
Abstract
Mixing events in stratified lakes result in microalgae being exposed to varying conditions in light and organic carbon concentrations. Stratified lakes consist of an upper illuminated strata and a lower, darker strata where organic carbon accumulates. Therefore, in this contribution we explore the importance of dissolved organic carbon for growth under various light intensities by measuring some ecophysiological adaptations in two green microalgae. We compared the non-motile Chlorella vulgaris with the flagellated Chlamydomonas acidophila under auto-, mixo-, and heterotrophic growth conditions. In both algae the maximum photosynthetic and growth rates were highest under mixotrophy, and both algae appeared inhibited in their phosphorus acquisition under heterotrophy. Heterotrophic conditions provoked the largest differences as C. vulgaris produced chlorophyll a in darkness and grew as well as in autotrophic conditions, whereas Chl. acidophila bleached and could not grow heterotrophically. Although the fatty acid composition of both phytoplankton species differed, both species reacted in a similar way to changes in their growth conditions, mainly by a decrease of C18:3n-3 and an increase of C18:1n-9 from auto- to heterotrophic conditions. The two contrasting responses within the group of green microalgae suggest that dissolved organic carbon has a high deterministic potential to explain the survival and behaviour of green algae in the deeper strata of lakes.
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Affiliation(s)
- Elly Spijkerman
- University of Potsdam, Dept. of Ecology and Ecosystem Modelling, Maulbeerallee 2, 14469 Potsdam, Germany.
| | - Marcus Lukas
- University of Potsdam, Dept. of Ecology and Ecosystem Modelling, Maulbeerallee 2, 14469 Potsdam, Germany
| | - Alexander Wacker
- University of Potsdam, Dept. of Theoretical Aquatic Ecology and Ecophysiology, Maulbeerallee 2, 14469 Potsdam, Germany
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329
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Cunliffe M, Hollingsworth A, Bain C, Sharma V, Taylor JD. Algal polysaccharide utilisation by saprotrophic planktonic marine fungi. FUNGAL ECOL 2017. [DOI: 10.1016/j.funeco.2017.08.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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330
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Rynearson TA. Navigating in a sea of genes. Science 2017; 358:1129-1130. [DOI: 10.1126/science.aar3431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Randomly generated microbial genomes produce realistic nutrient gradients in a model ocean
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Affiliation(s)
- Tatiana A. Rynearson
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA
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331
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Tucker SJ, McManus GB, Katz LA, Grattepanche JD. Distribution of Abundant and Active Planktonic Ciliates in Coastal and Slope Waters Off New England. Front Microbiol 2017; 8:2178. [PMID: 29250036 PMCID: PMC5715329 DOI: 10.3389/fmicb.2017.02178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 10/23/2017] [Indexed: 11/18/2022] Open
Abstract
Despite their important role of linking microbial and classic marine food webs, data on biogeographical patterns of microbial eukaryotic grazers are limited, and even fewer studies have used molecular tools to assess active (i.e., those expressing genes) community members. Marine ciliate diversity is believed to be greatest at the chlorophyll maximum, where there is an abundance of autotrophic prey, and is often assumed to decline with depth. Here, we assess the abundant (DNA) and active (RNA) marine ciliate communities throughout the water column at two stations off the New England coast (Northwest Atlantic)—a coastal station 43 km from shore (40 m depth) and a slope station 135 km off shore (1,000 m). We analyze ciliate communities using a DNA fingerprinting technique, Denaturing Gradient Gel Electrophoresis (DGGE), which captures patterns of abundant community members. We compare estimates of ciliate communities from SSU-rDNA (abundant) and SSU-rRNA (active) and find complex patterns throughout the water column, including many active lineages below the photic zone. Our analyses reveal (1) a number of widely-distributed taxa that are both abundant and active; (2) considerable heterogeneity in patterns of presence/absence of taxa in offshore samples taken 50 m apart throughout the water column; and (3) three distinct ciliate assemblages based on position from shore and depth. Analysis of active (RNA) taxa uncovers biodiversity hidden to traditional DNA-based approaches (e.g., clone library, rDNA amplicon studies).
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Affiliation(s)
- Sarah J Tucker
- Department of Biological Sciences, Smith College, Northampton, MA, United States
| | - George B McManus
- Department of Marine Sciences, University of Connecticut, Groton, CT, United States
| | - Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, MA, United States.,Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, United States
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332
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Pervasive, Genome-Wide Transcription in the Organelle Genomes of Diverse Plastid-Bearing Protists. G3-GENES GENOMES GENETICS 2017; 7:3789-3796. [PMID: 28935754 PMCID: PMC5677165 DOI: 10.1534/g3.117.300290] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Organelle genomes are among the most sequenced kinds of chromosome. This is largely because they are small and widely used in molecular studies, but also because next-generation sequencing technologies made sequencing easier, faster, and cheaper. However, studies of organelle RNA have not kept pace with those of DNA, despite huge amounts of freely available eukaryotic RNA-sequencing (RNA-seq) data. Little is known about organelle transcription in nonmodel species, and most of the available eukaryotic RNA-seq data have not been mined for organelle transcripts. Here, we use publicly available RNA-seq experiments to investigate organelle transcription in 30 diverse plastid-bearing protists with varying organelle genomic architectures. Mapping RNA-seq data to organelle genomes revealed pervasive, genome-wide transcription, regardless of the taxonomic grouping, gene organization, or noncoding content. For every species analyzed, transcripts covered ≥85% of the mitochondrial and/or plastid genomes (all of which were ≤105 kb), indicating that most of the organelle DNA—coding and noncoding—is transcriptionally active. These results follow earlier studies of model species showing that organellar transcription is coupled and ubiquitous across the genome, requiring significant downstream processing of polycistronic transcripts. Our findings suggest that noncoding organelle DNA can be transcriptionally active, raising questions about the underlying function of these transcripts and underscoring the utility of publicly available RNA-seq data for recovering complete genome sequences. If pervasive transcription is also found in bigger organelle genomes (>105 kb) and across a broader range of eukaryotes, this could indicate that noncoding organelle RNAs are regulating fundamental processes within eukaryotic cells.
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333
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Brodie J, Ball SG, Bouget FY, Chan CX, De Clerck O, Cock JM, Gachon C, Grossman AR, Mock T, Raven JA, Saha M, Smith AG, Vardi A, Yoon HS, Bhattacharya D. Biotic interactions as drivers of algal origin and evolution. THE NEW PHYTOLOGIST 2017; 216:670-681. [PMID: 28857164 DOI: 10.1111/nph.14760] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/10/2017] [Indexed: 05/07/2023]
Abstract
Contents 670 I. 671 II. 671 III. 676 IV. 678 678 References 678 SUMMARY: Biotic interactions underlie life's diversity and are the lynchpin to understanding its complexity and resilience within an ecological niche. Algal biologists have embraced this paradigm, and studies building on the explosive growth in omics and cell biology methods have facilitated the in-depth analysis of nonmodel organisms and communities from a variety of ecosystems. In turn, these advances have enabled a major revision of our understanding of the origin and evolution of photosynthesis in eukaryotes, bacterial-algal interactions, control of massive algal blooms in the ocean, and the maintenance and degradation of coral reefs. Here, we review some of the most exciting developments in the field of algal biotic interactions and identify challenges for scientists in the coming years. We foresee the development of an algal knowledgebase that integrates ecosystem-wide omics data and the development of molecular tools/resources to perform functional analyses of individuals in isolation and in populations. These assets will allow us to move beyond mechanistic studies of a single species towards understanding the interactions amongst algae and other organisms in both the laboratory and the field.
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Affiliation(s)
- Juliet Brodie
- Department of Life Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Steven G Ball
- UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Université de Lille CNRS, F 59000, Lille, France
| | - François-Yves Bouget
- Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, University Pierre et Marie Curie, University of Paris VI, CNRS, F-66650, Banyuls-sur-Mer, France
| | - Cheong Xin Chan
- Institute for Molecular Bioscience and School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Olivier De Clerck
- Phycology Research Group, Ghent University, Krijgslaan 281, S8, 9000, Gent, Belgium
| | - J Mark Cock
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, F-29688, France
| | | | - Arthur R Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Dundee, DD2 5DA, UK
| | - Mahasweta Saha
- Helmholtz Center for Ocean Research, Kiel, 24105, Germany
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Assaf Vardi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 440-746, South Korea
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
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Abstract
Vitamin B1 (thiamin) is a cofactor for critical enzymatic processes and is scarce in surface oceans. Several eukaryotic marine algal species thought to rely on exogenous thiamin are now known to grow equally well on the precursor 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP), including the haptophyte Emiliania huxleyi Because the thiamin biosynthetic capacities of the diverse and ecologically important haptophyte lineage are otherwise unknown, we investigated the pathway in transcriptomes and two genomes from 30 species representing six taxonomic orders. HMP synthase is missing in data from all studied taxa, but the pathway is otherwise complete, with some enzymatic variations. Experiments on axenic species from three orders demonstrated that equivalent growth rates were supported by 1 µM HMP or thiamin amendment. Cellular thiamin quotas were quantified in the oceanic phytoplankter E. huxleyi using the thiochrome assay. E. huxleyi exhibited luxury storage in standard algal medium [(1.16 ± 0.18) × 10-6 pmol thiamin cell-1], whereas quotas in cultures grown under more environmentally relevant thiamin and HMP supplies [(2.22 ± 0.07) × 10-7 or (1.58 ± 0.14) × 10-7 pmol thiamin cell-1, respectively] were significantly lower than luxury values and prior estimates. HMP and its salvage-related analog 4-amino-5-aminomethyl-2-methylpyrimidine (AmMP) supported higher growth than thiamin under environmentally relevant supply levels. These compounds also sustained growth of the stramenopile alga Pelagomonas calceolata Together with identification of a salvage protein subfamily (TENA_E) in multiple phytoplankton, the results indicate that salvaged AmMP and exogenously acquired HMP are used by several groups for thiamin production. Our studies highlight the potential importance of thiamin pathway intermediates and their analogs in shaping phytoplankton community structure.IMPORTANCE The concept that vitamin B1 (thiamin) availability in seawater controls the productivity and structure of eukaryotic phytoplankton communities has been discussed for half a century. We examined B1 biosynthesis and salvage pathways in diverse phytoplankton species. These comparative genomic analyses as well as experiments show that phytoplankton thought to require exogenous B1 not only utilize intermediate compounds to meet this need but also exhibit stronger growth on these compounds than on thiamin. Furthermore, oceanic phytoplankton have lower cellular thiamin quotas than previously reported, and salvage of intermediate compounds is likely a key mechanism for meeting B1 requirements under environmentally relevant scenarios. Thus, several lines of evidence now suggest that availability of specific precursor molecules could be more important in structuring phytoplankton communities than the vitamin itself. This understanding of preferential compound utilization and thiamin quotas will improve biogeochemical model parameterization and highlights interaction networks among ocean microbes.
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335
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Liang Y, Zhang Y, Wang N, Luo T, Zhang Y, Rivkin RB. Estimating Primary Production of Picophytoplankton Using the Carbon-Based Ocean Productivity Model: A Preliminary Study. Front Microbiol 2017; 8:1926. [PMID: 29051755 PMCID: PMC5633608 DOI: 10.3389/fmicb.2017.01926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/21/2017] [Indexed: 11/13/2022] Open
Abstract
Picophytoplankton are acknowledged to contribute significantly to primary production (PP) in the ocean while now the method to measure PP of picophytoplankton (PPPico) at large scales is not yet well established. Although the traditional 14C method and new technologies based on the use of stable isotopes (e.g., 13C) can be employed to accurately measure in situ PPPico, the time-consuming and labor-intensive shortage of these methods constrain their application in a survey on large spatiotemporal scales. To overcome this shortage, a modified carbon-based ocean productivity model (CbPM) is proposed for estimating the PPPico whose principle is based on the group-specific abundance, cellular carbon conversion factor (CCF), and temperature-derived growth rate of picophytoplankton. Comparative analysis showed that the estimated PPPico using CbPM method is significantly and positively related (r2 = 0.53, P < 0.001, n = 171) to the measured 14C uptake. This significant relationship suggests that CbPM has the potential to estimate the PPPico over large spatial and temporal scales. Currently this model application may be limited by the use of invariant cellular CCF and the relatively small data sets to validate the model which may introduce some uncertainties and biases. Model performance will be improved by the use of variable conversion factors and the larger data sets representing diverse growth conditions. Finally, we apply the CbPM-based model on the collected data during four cruises in the Bohai Sea in 2005. Model-estimated PPPico ranged from 0.1 to 11.9, 29.9 to 432.8, 5.5 to 214.9, and 2.4 to 65.8 mg C m-2 d-1 during March, June, September, and December, respectively. This study shed light on the estimation of global PPPico using carbon-based production model.
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Affiliation(s)
- Yantao Liang
- Research Center for Marine Biology and Carbon Sequestration, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Yongyu Zhang
- Research Center for Marine Biology and Carbon Sequestration, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Nannan Wang
- Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Tingwei Luo
- Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Yao Zhang
- Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Richard B Rivkin
- Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
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Dadon-Pilosof A, Conley KR, Jacobi Y, Haber M, Lombard F, Sutherland KR, Steindler L, Tikochinski Y, Richter M, Glöckner FO, Suzuki MT, West NJ, Genin A, Yahel G. Surface properties of SAR11 bacteria facilitate grazing avoidance. Nat Microbiol 2017; 2:1608-1615. [PMID: 28970475 DOI: 10.1038/s41564-017-0030-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 08/18/2017] [Indexed: 11/09/2022]
Abstract
Oceanic ecosystems are dominated by minute microorganisms that play a major role in food webs and biogeochemical cycles 1 . Many microorganisms thrive in the dilute environment due to their capacity to locate, attach to, and use patches of nutrients and organic matter 2,3 . We propose that some free-living planktonic bacteria have traded their ability to stick to nutrient-rich organic particles for a non-stick cell surface that helps them evade predation by mucous filter feeders. We used a combination of in situ sampling techniques and next-generation sequencing to study the biological filtration of microorganisms at the phylotype level. Our data indicate that some marine bacteria, most notably the highly abundant Pelagibacter ubique and most other members of the SAR 11 clade of the Alphaproteobacteria, can evade filtration by slipping through the mucous nets of both pelagic and benthic tunicates. While 0.3 µm polystyrene beads and other similarly-sized bacteria were efficiently filtered, SAR11 members were not captured. Reversed-phase chromatography revealed that most SAR11 bacteria have a much less hydrophobic cell surface than that of other planktonic bacteria. Our data call for a reconsideration of the role of surface properties in biological filtration and predator-prey interactions in aquatic systems.
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Affiliation(s)
- Ayelet Dadon-Pilosof
- The School of Marine Science, Ruppin Academic Center, 4029700, Michmoret, Israel. .,Department of Ecology, Evolution & Behavior, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel.
| | - Keats R Conley
- Oregon Institute of Marine Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Yuval Jacobi
- The School of Marine Science, Ruppin Academic Center, 4029700, Michmoret, Israel.,School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, 69978, Tel Aviv, Israel
| | - Markus Haber
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 3498838, Haifa, Israel
| | - Fabien Lombard
- Sorbonne Universités, Université Pierre et Marie Curie, Observatoire Océanologique de Villefranche-Sur-Mer (OOV), Laboratoire d'Océanographie de Villefranche-sur-Mer, 06230, Villefranche-sur-Mer, France
| | - Kelly R Sutherland
- Oregon Institute of Marine Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Laura Steindler
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 3498838, Haifa, Israel
| | - Yaron Tikochinski
- The School of Marine Science, Ruppin Academic Center, 4029700, Michmoret, Israel
| | - Michael Richter
- Max Planck Institute for Marine Microbiology Microbial Genomics and Bioinformatics Research Group Celsiusstrasse 1, 28359, Bremen, Germany
| | - Frank Oliver Glöckner
- Max Planck Institute for Marine Microbiology Microbial Genomics and Bioinformatics Research Group Celsiusstrasse 1, 28359, Bremen, Germany.,Jacobs University, Campusring 1, 28759, Bremen, Germany
| | - Marcelino T Suzuki
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire Océanologique, F-66650, Banyuls-sur-mer, France
| | - Nyree J West
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Observatoire Océanologique de Banyuls (OOB), F-66650, Banyuls-sur-mer, France
| | - Amatzia Genin
- Department of Ecology, Evolution & Behavior, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, 8810302, Eilat, Israel
| | - Gitai Yahel
- The School of Marine Science, Ruppin Academic Center, 4029700, Michmoret, Israel
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338
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Santoferrara LF, McManus GB. Integrating dimensions of biodiversity in choreotrichs and oligotrichs of marine plankton. Eur J Protistol 2017; 61:323-330. [DOI: 10.1016/j.ejop.2017.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 03/22/2017] [Accepted: 04/04/2017] [Indexed: 01/01/2023]
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339
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Brocks JJ, Jarrett AJM, Sirantoine E, Hallmann C, Hoshino Y, Liyanage T. The rise of algae in Cryogenian oceans and the emergence of animals. Nature 2017; 548:578-581. [DOI: 10.1038/nature23457] [Citation(s) in RCA: 296] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 07/03/2017] [Indexed: 02/01/2023]
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340
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Anderson R, Jürgens K, Hansen PJ. Mixotrophic Phytoflagellate Bacterivory Field Measurements Strongly Biased by Standard Approaches: A Case Study. Front Microbiol 2017; 8:1398. [PMID: 28798734 PMCID: PMC5526857 DOI: 10.3389/fmicb.2017.01398] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 07/10/2017] [Indexed: 11/13/2022] Open
Abstract
Bacterivory among small (≤20 μm) phytoflagellates (SP) is increasingly recognized as a globally relevant phenomenon, impacting a wide range of aspects from primary production levels to marine fisheries. However, to correctly parametrize mixotrophic SP in biogeochemical and food web models, a better understanding of the magnitude and regulation of in situ SP feeding is urgently needed. Current methods to determine SP bacterivory in the field may introduce biases by treating these organisms as equivalent to heterotrophic nanoflagellates (HNF). In the present case study we experimentally tested two generally employed assumptions of such studies: (A) bacterivory rates of the whole SP community and of distinct SP groups remain constant over 'short' time scales (hours to a day) and (B) SP community ingestion rates approximate the average ingestion rate of all feeding individuals. Food vacuole markers (acidotropic probes), were applied along the diel cycle at three stations in December 2015, and May and June 2016. In December and June, surrogate prey (fluorescently labeled bacteria) were used in parallel at one sampling station. Sampling at different times of day produced an up to fourfold difference in estimates of SP daily bacterivorous impact. In contrast, daily bacterivory estimates for HNF remained constant in almost all cases. The perceived principal SP bacterivorous groups also shifted strongly. As an example, picoeukaryotes dominated total SP bacterivory in daylight hours but completely ceased to feed at night. Finally, a large fraction of the SP community was not feeding at all time points tested. This lead to significant errors in estimated ingestion rates determined using the whole SP community, being up to 16 times lower than those determined solely for actively feeding mixotrophic SP. Overall, this case study indicates that applying the two commonly used premises outlined above can introduce significant biases and considerably alter our perception of mixotrophy in a given system.
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Affiliation(s)
- Ruth Anderson
- Marine Biological Section, Department of Biology, University of CopenhagenHelsingør, Denmark
| | - Klaus Jürgens
- Leibniz Institute for Baltic Sea ResearchRostock, Germany
| | - Per J Hansen
- Marine Biological Section, Department of Biology, University of CopenhagenHelsingør, Denmark
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341
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Gomaa F, Garcia PA, Delaney J, Girguis PR, Buie CR, Edgcomb VP. Toward establishing model organisms for marine protists: Successful transfection protocols for Parabodo caudatus (Kinetoplastida: Excavata). Environ Microbiol 2017. [PMID: 28631386 DOI: 10.1111/1462-2920.13830] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We developed protocols for, and demonstrated successful transfection of, the free-living kinetoplastid flagellate Parabodo caudatus with three plasmids carrying a fluorescence reporter gene (pEF-GFP with the EF1 alpha promoter, pUB-GFP with Ubiquitin C promoter, and pEYFP-Mitotrap with CMV promoter). We evaluated three electroporation approaches: (1) a square-wave electroporator designed for eukaryotes, (2) a novel microfluidic transfection system employing hydrodynamically-controlled electric field waveforms, and (3) a traditional exponential decay electroporator. We found the microfluidic device provides a simple and efficient platform to quickly test a wide range of electric field parameters to find the optimal set of conditions for electroporation of target species. It also allows for processing large sample volumes (>10 ml) within minutes, increasing throughput 100 times over cuvettes. Fluorescence signal from the reporter gene was detected a few hours after transfection and persisted for 3 days in cells transfected by pEF-GFP and pUB-GFP plasmids and for at least 5 days post-transfection for cells transfected with pEYFP-Mitotrap. Expression of the reporter genes (GFP and YFP) was also confirmed using reverse transcription-PCR (RT-PCR). This work opens the door for further efforts with this taxon and close relatives toward establishing model systems for genome editing.
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Affiliation(s)
- Fatma Gomaa
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Paulo A Garcia
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jennifer Delaney
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Peter R Girguis
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Cullen R Buie
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Virginia P Edgcomb
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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342
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Xu D, Li R, Hu C, Sun P, Jiao N, Warren A. Microbial Eukaryote Diversity and Activity in the Water Column of the South China Sea Based on DNA and RNA High Throughput Sequencing. Front Microbiol 2017; 8:1121. [PMID: 28659910 PMCID: PMC5469884 DOI: 10.3389/fmicb.2017.01121] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 06/01/2017] [Indexed: 12/20/2022] Open
Abstract
To study the diversity and metabolic activity of microbial eukaryotes in the water column of the South China Sea, genomic DNA and RNA were co-extracted from samples collected down to bathyal depth at two sites. V9 regions of both SSU rRNA gene and its transcript (cDNA) were amplified and sequenced using high throughput sequencing. Our study revealed: (1) DNA and RNA datasets showed significant differences in microbial eukaryote community composition, with the variability between the two datasets for the same sample exceeding that between samples within each dataset, indicating that nucleic acid source overrode environmental factors in determining the composition of microeukaryotes; (2) despite the differences in community composition between the two datasets, both DNA and RNA revealed similar depth-related distribution patterns of microbial eukaryotes; (3) using the ratio of RNA: DNA as a proxy of relative metabolic activity, a depth-related pattern was found for the relative metabolic activity of some but not all groups of microbial eukaryotes, with the highest activity for the groups with depth-related pattern usually found in the middle water layers; and (4) the presence of live and active photoautotrophic microbial eukaryotes in the deep ocean was confirmed, indicating that they play an important role in controlling the deep-sea organic carbon pool. Overall, our study sheds light on the diversity and activity of microbial eukaryotes in the water column of a tropical oligotrophic ocean and their potential contributions in the downward transportation of organic material from the surface ocean to the deep via the biological pump.
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Affiliation(s)
- Dapeng Xu
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen UniversityXiamen, China
| | - Ran Li
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen UniversityXiamen, China
| | - Chen Hu
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen UniversityXiamen, China
| | - Ping Sun
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment and Ecology, Xiamen UniversityXiamen, China
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen UniversityXiamen, China
| | - Alan Warren
- Department of Life Sciences, Natural History MuseumLondon, United Kingdom
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343
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344
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Autotrophic and heterotrophic acquisition of carbon and nitrogen by a mixotrophic chrysophyte established through stable isotope analysis. ISME JOURNAL 2017; 11:2022-2034. [PMID: 28524870 PMCID: PMC5563956 DOI: 10.1038/ismej.2017.68] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/20/2017] [Accepted: 04/03/2017] [Indexed: 12/24/2022]
Abstract
Collectively, phagotrophic algae (mixotrophs) form a functional continuum of nutritional modes between autotrophy and heterotrophy, but the specific physiological benefits of mixotrophic nutrition differ among taxa. Ochromonas spp. are ubiquitous chrysophytes that exhibit high nutritional flexibility, although most species generally fall towards the heterotrophic end of the mixotrophy spectrum. We assessed the sources of carbon and nitrogen in Ochromonas sp. strain BG-1 growing mixotrophically via short-term stable isotope probing. An axenic culture was grown in the presence of either heat-killed bacteria enriched with 15N and 13C, or unlabeled heat-killed bacteria and labeled inorganic substrates (13C-bicarbonate and 15N-ammonium). The alga exhibited high growth rates (up to 2 divisions per day) only until heat-killed bacteria were depleted. NanoSIMS and bulk IRMS isotope analyses revealed that Ochromonas obtained 84-99% of its carbon and 88-95% of its nitrogen from consumed bacteria. The chrysophyte assimilated inorganic 13C-carbon and 15N-nitrogen when bacterial abundances were very low, but autotrophic (photosynthetic) activity was insufficient to support net population growth of the alga. Our use of nanoSIMS represents its first application towards the study of a mixotrophic alga, enabling a better understanding and quantitative assessment of carbon and nutrient acquisition by this species.
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345
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Affiliation(s)
- Alexandra Z Worden
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA. .,Integrated Microbial Biodiversity Program, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Susanne Wilken
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA
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346
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Responses of the picoprasinophyte Micromonas commoda to light and ultraviolet stress. PLoS One 2017; 12:e0172135. [PMID: 28278262 PMCID: PMC5344333 DOI: 10.1371/journal.pone.0172135] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 01/31/2017] [Indexed: 11/19/2022] Open
Abstract
Micromonas is a unicellular marine green alga that thrives from tropical to polar ecosystems. We investigated the growth and cellular characteristics of acclimated mid-exponential phase Micromonas commoda RCC299 over multiple light levels and over the diel cycle (14:10 hour light:dark). We also exposed the light:dark acclimated M. commoda to experimental shifts from moderate to high light (HL), and to HL plus ultraviolet radiation (HL+UV), 4.5 hours into the light period. Cellular responses of this prasinophyte were quantified by flow cytometry and changes in gene expression by qPCR and RNA-seq. While proxies for chlorophyll a content and cell size exhibited similar diel variations in HL and controls, with progressive increases during day and decreases at night, both parameters sharply decreased after the HL+UV shift. Two distinct transcriptional responses were observed among chloroplast genes in the light shift experiments: i) expression of transcription and translation-related genes decreased over the time course, and this transition occurred earlier in treatments than controls; ii) expression of several photosystem I and II genes increased in HL relative to controls, as did the growth rate within the same diel period. However, expression of these genes decreased in HL+UV, likely as a photoprotective mechanism. RNA-seq also revealed two genes in the chloroplast genome, ycf2-like and ycf1-like, that had not previously been reported. The latter encodes the second largest chloroplast protein in Micromonas and has weak homology to plant Ycf1, an essential component of the plant protein translocon. Analysis of several nuclear genes showed that the expression of LHCSR2, which is involved in non-photochemical quenching, and five light-harvesting-like genes, increased 30 to >50-fold in HL+UV, but was largely unchanged in HL and controls. Under HL alone, a gene encoding a novel nitrite reductase fusion protein (NIRFU) increased, possibly reflecting enhanced N-assimilation under the 625 μmol photons m-2 s-1 supplied in the HL treatment. NIRFU’s domain structure suggests it may have more efficient electron transfer than plant NIR proteins. Our analyses indicate that Micromonas can readily respond to abrupt environmental changes, such that strong photoinhibition was provoked by combined exposure to HL and UV, but a ca. 6-fold increase in light was stimulatory.
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347
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Lie AAY, Liu Z, Terrado R, Tatters AO, Heidelberg KB, Caron DA. Effect of light and prey availability on gene expression of the mixotrophic chrysophyte, Ochromonas sp. BMC Genomics 2017; 18:163. [PMID: 28196482 PMCID: PMC5310065 DOI: 10.1186/s12864-017-3549-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 02/02/2017] [Indexed: 12/21/2022] Open
Abstract
Background Ochromonas is a genus of mixotrophic chrysophytes that is found ubiquitously in many aquatic environments. Species in this genus can be important consumers of bacteria but vary in their ability to perform photosynthesis. We studied the effect of light and bacteria on growth and gene expression of a predominantly phagotrophic Ochromonas species. Axenic cultures of Ochromonas sp. were fed with heat-killed bacteria (HKB) and grown in constant light or darkness. RNA was extracted from cultures in the light or in the dark with HKB present (Light + HKB; Dark + HKB), and in the light after HKB were depleted (Light + depleted HKB). Results There were no significant differences in the growth or bacterial ingestion rates between algae grown in light or dark conditions. The availability of light led to a differential expression of only 8% of genes in the transcriptome. A number of genes associated with photosynthesis, phagotrophy, and tetrapyrrole synthesis was upregulated in the Light + HKB treatment compared to Dark + HKB. Conversely, the comparison between the Light + HKB and Light + depleted HKB treatments revealed that the presence of HKB led to differential expression of 59% of genes, including the majority of genes involved in major carbon and nitrogen metabolic pathways. Genes coding for unidirectional enzymes for the utilization of glucose were upregulated in the presence of HKB, implying increased glycolytic activities during phagotrophy. Algae without HKB upregulated their expression of genes coding for ammonium transporters, implying uptake of inorganic nitrogen from the culture medium when prey were unavailable. Conclusions Transcriptomic results agreed with previous observations that light had minimal effect on the population growth of Ochromonas sp. However, light led to the upregulation of a number of phototrophy- and phagotrophy-related genes, while the availability of bacterial prey led to prominent changes in major carbon and nitrogen metabolic pathways. Our study demonstrated the potential of transcriptomic approaches to improve our understanding of the trophic physiologies of complex mixotrophs, and revealed responses in Ochromonas sp. not apparent from traditional culture studies. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3549-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alle A Y Lie
- Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA, 90089-0371, USA.
| | - Zhenfeng Liu
- Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA, 90089-0371, USA
| | - Ramon Terrado
- Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA, 90089-0371, USA
| | - Avery O Tatters
- Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA, 90089-0371, USA
| | - Karla B Heidelberg
- Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA, 90089-0371, USA
| | - David A Caron
- Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA, 90089-0371, USA
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348
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Jones BM, Kustka AB. A quantitative SMRT cell sequencing method for ribosomal amplicons. J Microbiol Methods 2017; 135:77-84. [PMID: 28159629 DOI: 10.1016/j.mimet.2017.01.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/27/2017] [Accepted: 01/28/2017] [Indexed: 11/18/2022]
Abstract
Advances in sequencing technologies continue to provide unprecedented opportunities to characterize microbial communities. For example, the Pacific Biosciences Single Molecule Real-Time (SMRT) platform has emerged as a unique approach harnessing DNA polymerase activity to sequence template molecules, enabling long reads at low costs. With the aim to simultaneously classify and enumerate in situ microbial populations, we developed a quantitative SMRT (qSMRT) approach that involves the addition of exogenous standards to quantify ribosomal amplicons derived from environmental samples. The V7-9 regions of 18S SSU rDNA were targeted and quantified from protistan community samples collected in the Ross Sea during the Austral summer of 2011. We used three standards of different length and optimized conditions to obtain accurate quantitative retrieval across the range of expected amplicon sizes, a necessary criterion for analyzing taxonomically diverse 18S rDNA molecules from natural environments. The ability to concurrently identify and quantify microorganisms in their natural environment makes qSMRT a powerful, rapid and cost-effective approach for defining ecosystem diversity and function.
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Affiliation(s)
- Bethan M Jones
- Department of Earth and Environmental Sciences, Rutgers University-Newark, Newark, NJ 07102, United States.
| | - Adam B Kustka
- Department of Earth and Environmental Sciences, Rutgers University-Newark, Newark, NJ 07102, United States
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349
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Hirth M, Liverani S, Mahlow S, Bouget FY, Pohnert G, Sasso S. Metabolic profiling identifies trehalose as an abundant and diurnally fluctuating metabolite in the microalga Ostreococcus tauri. Metabolomics 2017; 13:68. [PMID: 28473745 PMCID: PMC5392535 DOI: 10.1007/s11306-017-1203-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/31/2017] [Indexed: 12/18/2022]
Abstract
INTRODUCTION The picoeukaryotic alga Ostreococcus tauri (Chlorophyta) belongs to the widespread group of marine prasinophytes. Despite its ecological importance, little is known about the metabolism of this alga. OBJECTIVES In this work, changes in the metabolome were quantified when O. tauri was grown under alternating cycles of 12 h light and 12 h darkness. METHODS Algal metabolism was analyzed by gas chromatography-mass spectrometry. Using fluorescence-activated cell sorting, the bacteria associated with O. tauri were depleted to below 0.1% of total cells at the time of metabolic profiling. RESULTS Of 111 metabolites quantified over light-dark cycles, 20 (18%) showed clear diurnal variations. The strongest fluctuations were found for trehalose. With an intracellular concentration of 1.6 mM in the dark, this disaccharide was six times more abundant at night than during the day. This fluctuation pattern of trehalose may be a consequence of starch degradation or of the synchronized cell cycle. On the other hand, maltose (and also sucrose) was below the detection limit (~10 μM). Accumulation of glycine in the light is in agreement with the presence of a classical glycolate pathway of photorespiration. We also provide evidence for the presence of fatty acid methyl and ethyl esters in O. tauri. CONCLUSIONS This study shows how the metabolism of O. tauri adapts to day and night and gives new insights into the configuration of the carbon metabolism. In addition, several less common metabolites were identified.
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Affiliation(s)
- Matthias Hirth
- 0000 0001 1939 2794grid.9613.dInstitute of General Botany and Plant Physiology, Friedrich Schiller University, Jena, Germany
| | - Silvia Liverani
- 0000 0001 0724 6933grid.7728.aDepartment of Mathematics, Brunel University London, Uxbridge, UK
| | - Sebastian Mahlow
- 0000 0001 1939 2794grid.9613.dInstitute of General Botany and Plant Physiology, Friedrich Schiller University, Jena, Germany
| | - François-Yves Bouget
- 0000 0001 2369 4306grid.463752.1Sorbonne Universités, UPMC Univ Paris 06 & Centre National pour la Recherche Scientifique CNRS, UMR 7621, Laboratoire d’Océanographie Microbienne, Observatoire Océanologique, Banyuls-sur-Mer, France
| | - Georg Pohnert
- 0000 0001 1939 2794grid.9613.dInstitute for Inorganic and Analytical Chemistry, Friedrich Schiller University, Jena, Germany
- 0000 0004 0491 7131grid.418160.aMax Planck Institute for Chemical Ecology, Jena, Germany
| | - Severin Sasso
- 0000 0001 1939 2794grid.9613.dInstitute of General Botany and Plant Physiology, Friedrich Schiller University, Jena, Germany
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350
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Selosse MA, Charpin M, Not F. Mixotrophy everywhere on land and in water: thegrand écarthypothesis. Ecol Lett 2016; 20:246-263. [DOI: 10.1111/ele.12714] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/22/2016] [Accepted: 11/13/2016] [Indexed: 01/22/2023]
Affiliation(s)
- Marc-André Selosse
- Institut de Systématique, Évolution; Biodiversité (ISYEB - UMR 7205 - CNRS; MNHN; UPMC; EPHE); Muséum national d'Histoire naturelle; Sorbonne Universités; 57 rue Cuvier CP50 75005 Paris France
- Department of Plant Taxonomy and Nature Conservation; University of Gdansk; Wita Stwosza 59 80-308 Gdansk Poland
| | - Marie Charpin
- Université Blaise Pascal; Clermont-Ferrand; CNRS Laboratoire micro-organismes: Génome et Environnement; UMR 6023 1 Impasse Amélie Murat 63178 Aubière France
| | - Fabrice Not
- Sorbonne Universités; UPMC Université Paris 06; CNRS; Laboratoire Adaptation et Diversité en Milieu Marin UMR7144; Station Biologique de Roscoff; 29680 Roscoff France
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