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Celepli N, Sundh J, Ekman M, Dupont CL, Yooseph S, Bergman B, Ininbergs K. Meta-omic analyses of Baltic Sea cyanobacteria: diversity, community structure and salt acclimation. Environ Microbiol 2017; 19:673-686. [PMID: 27871145 DOI: 10.1111/1462-2920.13592] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 11/16/2016] [Indexed: 01/08/2023]
Abstract
Cyanobacteria are important phytoplankton in the Baltic Sea, an estuarine-like environment with pronounced north to south gradients in salinity and nutrient concentrations. Here, we present a metagenomic and -transcriptomic survey, with subsequent analyses targeting the genetic identity, phylogenetic diversity, and spatial distribution of Baltic Sea cyanobacteria. The cyanobacterial community constituted close to 12% of the microbial population sampled during a pre-bloom period (June-July 2009). The community was dominated by unicellular picocyanobacteria, specifically a few highly abundant taxa (Synechococcus and Cyanobium) with a long tail of low abundance representatives, and local peaks of bloom-forming heterocystous taxa. Cyanobacteria in the Baltic Sea differed genetically from those in adjacent limnic and marine waters as well as from cultivated and sequenced picocyanobacterial strains. Diversity peaked at brackish salinities 3.5-16 psu, with low N:P ratios. A shift in community composition from brackish to marine strains was accompanied by a change in the repertoire and expression of genes involved in salt acclimation. Overall, the pre-bloom cyanobacterial population was more genetically diverse, widespread and abundant than previously documented, with unicellular picocyanobacteria being the most abundant clade along the entire Baltic Sea salinity gradient.
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Affiliation(s)
- Narin Celepli
- Department of Ecology, Environment and Plant Sciences, Stockholm University/Science for Life Laboratory, Solna, 17121, Sweden
| | - John Sundh
- Centre for Ecology and Evolution in Microbial model Systems, Linnaeus University, Kalmar, 391 82, Sweden
| | - Martin Ekman
- Department of Ecology, Environment and Plant Sciences, Stockholm University/Science for Life Laboratory, Solna, 17121, Sweden
| | - Chris L Dupont
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, CA, 92037, USA
| | - Shibu Yooseph
- Department of Computer Science, University of Central Florida, Orlando, FL, USA
| | - Birgitta Bergman
- Department of Ecology, Environment and Plant Sciences, Stockholm University/Science for Life Laboratory, Solna, 17121, Sweden
| | - Karolina Ininbergs
- Department of Ecology, Environment and Plant Sciences, Stockholm University/Science for Life Laboratory, Solna, 17121, Sweden
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Dupont CL, Larsson J, Yooseph S, Ininbergs K, Goll J, Asplund-Samuelsson J, McCrow JP, Celepli N, Allen LZ, Ekman M, Lucas AJ, Hagström Å, Thiagarajan M, Brindefalk B, Richter AR, Andersson AF, Tenney A, Lundin D, Tovchigrechko A, Nylander JAA, Brami D, Badger JH, Allen AE, Rusch DB, Hoffman J, Norrby E, Friedman R, Pinhassi J, Venter JC, Bergman B. Functional tradeoffs underpin salinity-driven divergence in microbial community composition. PLoS One 2014; 9:e89549. [PMID: 24586863 PMCID: PMC3937345 DOI: 10.1371/journal.pone.0089549] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 01/23/2014] [Indexed: 11/23/2022] Open
Abstract
Bacterial community composition and functional potential change subtly across gradients in the surface ocean. In contrast, while there are significant phylogenetic divergences between communities from freshwater and marine habitats, the underlying mechanisms to this phylogenetic structuring yet remain unknown. We hypothesized that the functional potential of natural bacterial communities is linked to this striking divide between microbiomes. To test this hypothesis, metagenomic sequencing of microbial communities along a 1,800 km transect in the Baltic Sea area, encompassing a continuous natural salinity gradient from limnic to fully marine conditions, was explored. Multivariate statistical analyses showed that salinity is the main determinant of dramatic changes in microbial community composition, but also of large scale changes in core metabolic functions of bacteria. Strikingly, genetically and metabolically different pathways for key metabolic processes, such as respiration, biosynthesis of quinones and isoprenoids, glycolysis and osmolyte transport, were differentially abundant at high and low salinities. These shifts in functional capacities were observed at multiple taxonomic levels and within dominant bacterial phyla, while bacteria, such as SAR11, were able to adapt to the entire salinity gradient. We propose that the large differences in central metabolism required at high and low salinities dictate the striking divide between freshwater and marine microbiomes, and that the ability to inhabit different salinity regimes evolved early during bacterial phylogenetic differentiation. These findings significantly advance our understanding of microbial distributions and stress the need to incorporate salinity in future climate change models that predict increased levels of precipitation and a reduction in salinity.
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Affiliation(s)
- Chris L. Dupont
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, California, United States of America
- * E-mail: (CLD); (JL)
| | - John Larsson
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- * E-mail: (CLD); (JL)
| | - Shibu Yooseph
- Informatics Group, J. Craig Venter Institute, San Diego, California, United States of America
| | - Karolina Ininbergs
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Johannes Goll
- Informatics Group, J. Craig Venter Institute, Rockville, Maryland, United States of America
| | | | - John P. McCrow
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, California, United States of America
| | - Narin Celepli
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Lisa Zeigler Allen
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, California, United States of America
| | - Martin Ekman
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Andrew J. Lucas
- Marine Physical Laboratory, Scripps Institution of Oceanography, University of California San Diego, San Diego, California, United States of America
| | - Åke Hagström
- Swedish Institute for the Marine Environment (SIME), University of Gothenburg, Gothenburg, Sweden
| | - Mathangi Thiagarajan
- Informatics Group, J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Björn Brindefalk
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Alexander R. Richter
- Informatics Group, J. Craig Venter Institute, San Diego, California, United States of America
| | - Anders F. Andersson
- KTH Royal Institute of Technology, Science for Life Laboratory, School of Biotechnology, Solna, Sweden
| | - Aaron Tenney
- Informatics Group, J. Craig Venter Institute, San Diego, California, United States of America
| | - Daniel Lundin
- KTH Royal Institute of Technology, Science for Life Laboratory, School of Biotechnology, Solna, Sweden
| | - Andrey Tovchigrechko
- Informatics Group, J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Johan A. A. Nylander
- Department of Biodiversity Informatics, Swedish Museum of Natural History, Stockholm, Sweden
| | - Daniel Brami
- Informatics Group, J. Craig Venter Institute, San Diego, California, United States of America
| | - Jonathan H. Badger
- Informatics Group, J. Craig Venter Institute, San Diego, California, United States of America
| | - Andrew E. Allen
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, California, United States of America
| | - Douglas B. Rusch
- Informatics Group, J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Jeff Hoffman
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, California, United States of America
| | - Erling Norrby
- Center for History of Science, The Royal Swedish Academy of Sciences, Stockholm, Sweden
| | - Robert Friedman
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, California, United States of America
| | - Jarone Pinhassi
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden
| | - J. Craig Venter
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, California, United States of America
| | - Birgitta Bergman
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
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Berntzon L, Erasmie S, Celepli N, Eriksson J, Rasmussen U, Bergman B. BMAA inhibits nitrogen fixation in the cyanobacterium Nostoc sp. PCC 7120. Mar Drugs 2013; 11:3091-108. [PMID: 23966039 PMCID: PMC3766884 DOI: 10.3390/md11083091] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/21/2013] [Accepted: 07/31/2013] [Indexed: 11/28/2022] Open
Abstract
Cyanobacteria produce a range of secondary metabolites, one being the neurotoxic non-protein amino acid β-N-methylamino-L-alanine (BMAA), proposed to be a causative agent of human neurodegeneration. As for most cyanotoxins, the function of BMAA in cyanobacteria is unknown. Here, we examined the effects of BMAA on the physiology of the filamentous nitrogen-fixing cyanobacterium Nostoc sp. PCC 7120. Our data show that exogenously applied BMAA rapidly inhibits nitrogenase activity (acetylene reduction assay), even at micromolar concentrations, and that the inhibition was considerably more severe than that induced by combined nitrogen sources and most other amino acids. BMAA also caused growth arrest and massive cellular glycogen accumulation, as observed by electron microscopy. With nitrogen fixation being a process highly sensitive to oxygen species we propose that the BMAA effects found here may be related to the production of reactive oxygen species, as reported for other organisms.
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Affiliation(s)
- Lotta Berntzon
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm S-10691, Sweden.
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