77 research outputs found

    Data from the long term experiment and phytoplankton tableNodularia table from Evolving interactions between diazotrophic cyanobacterium and phage mediate nitrogen release and host competitive ability

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    Interactions between nitrogen-fixing (i.e. diazotrophic) cyanobacteria and their viruses, cyanophages, can have large-scale ecosystem effects. These effects are mediated by temporal alterations in nutrient availability in aquatic systems owing to the release of nitrogen and carbon sources from cells lysed by phages, as well as by ecologically important changes in the diversity and fitness of cyanobacterial populations that evolve in the presence of phages. However, ecological and evolutionary feedbacks between phages and nitrogen-fixing cyanobacteria are still relative poorly understood. Here, we used an experimental evolution approach to test the effect of interactions between a common filamentous, nitrogen-fixing cyanobacterium (<i>Nodularia</i> sp.) and its phage on cellular nitrogen release and host properties. Ecological, community-level effects of phage-mediated nitrogen release were tested with a phytoplankton bioassay. We found that cyanobacterial nitrogen release increased significantly as a result of viral lysis, which was associated with enhanced growth of phytoplankton species in cell-free filtrates compared with phage-resistant host controls in which lysis and subsequent nutrient release did not occur after phage exposure. We also observed an ecologically important change among phage-evolved cyanobacteria with phage-resistant phenotypes, a short-filamentous morphotype with reduced buoyancy compared with the ancestral long-filamentous morphotype. Reduced buoyancy might decrease the ability of these morphotypes to compete for light compared with longer, more buoyant filaments. Together, these findings demonstrate the potential of cyanobacteria‚Äďphage interactions to affect ecosystem biogeochemical cycles and planktonic community dynamics

    Composite mass chromatograms showing the distribution of heterocyst glycolipids (HGs) in Baltic Sea cyanobacteria.

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    <p>Composite mass chromatograms showing the distribution of heterocyst glycolipids (HGs) in Baltic Sea cyanobacteria.</p

    Correspondence analysis of the various lipid classes present in Baltic Sea cyanobacteria.

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    <p>Distribution patterns of (a) whole cell lipid distributions, (b) hydrocarbons, (c) fatty acid methyl esters, (d) bacteriohopanepolyols and (e) heterocyst glycolipids in the three genera of heterocystous cyanobacteria investigated. Dots indicate position of individual lipid biomarkers in relation to <i>Aphanizomenon</i> (square), <i>Dolichospermum</i> (triangles) and <i>Nodularia</i> (diamonds). Ellipses group the different genera of heterocystous cyanobacteria; <i>Aphanizomenon</i> (yellow), <i>Dolichospermum</i> (red) and <i>Nodularia</i> (blue).</p


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    <p>Salinity is an important abiotic factor controlling the distribution and abundance of Nodularia spumigena, the dominating diazotrophic and toxic phototroph, in the brackish water cyanobacterial blooms of the Baltic Sea. To expand the available genomic information for brackish water cyanobacteria, we sequenced the isolate Nodularia spumigena UHCC 0039 using an Illumina-SMRT hybrid sequencing approach, revealing a chromosome of 5,294,286 base pairs (bp) and a single plasmid of 92,326 bp. Comparative genomics in Nostocales showed pronounced genetic similarity among Nodularia spumigena strains evidencing their short evolutionary history. The studied Baltic Sea strains share similar sets of CRISPR-Cas cassettes and a higher number of insertion sequence (IS) elements compared to Nodularia spumigena CENA596 isolated from a shrimp production pond in Brazil. Nodularia spumigena UHCC 0039 proliferated similarly at three tested salinities, whereas the lack of salt inhibited its growth and triggered transcriptome remodeling, including the up-regulation of five sigma factors and the down-regulation of two other sigma factors, one of which is specific for strain UHCC 0039. Down-regulated genes additionally included a large genetic region for the synthesis of two yet unidentified natural products. Our results indicate a remarkable plasticity of the Nodularia salinity acclimation, and thus salinity strongly impacts the intensity and distribution of cyanobacterial blooms in the Baltic Sea.</p

    Relative abundance of bacteriohopanepolyols (BHPs) in Baltic Sea cyanobacteria.

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    <p>Strains 315, BIR53 and BIR169 belong to the genus <i>Dolichospermum</i>, while strain TR183 is representative of the genus <i>Aphanizomenon</i>. Note that no BHPs were detected in strains of the genus <i>Nodularia</i>. BHT CE = BHT cyclitol ether; BHT G = BHT glucosamine; guanidine BHT CE = guanidine substituted BHT cyclitol ether; guanidine BHT G = guanidine substituted BHT glucosamine.</p

    Distribution of FAMEs in Baltic Sea cyanobacteria belonging to the genera <i>Dolichospermum</i>, <i>Aphanizomenon</i> and <i>Nodularia</i>.

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    <p>Distribution of FAMEs in Baltic Sea cyanobacteria belonging to the genera <i>Dolichospermum</i>, <i>Aphanizomenon</i> and <i>Nodularia</i>.</p
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