Expression profiling of the bloom-forming cyanobacterium <i>Nodularia</i> CCY9414 under light and oxidative stress conditions

Kopf, Matthias; Möke, Fred; Bauwe, Hermann; Hess, Wolfgang R.; Hagemann, Martin

doi:10.1038/ismej.2015.16

Cited by 31 publications

(26 citation statements)

References 48 publications

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“…5). This knowledge provides guidance for laboratory-based studies of Antarctic microorganisms by highlighting the specific environmental variables that are relevant for developing the conceptual framework and experimental design of research, and for drawing conclusions that have environmental relevance 16,17,101,102 .…”

Section: Resultsmentioning

confidence: 99%

Microbial ecology of Antarctic aquatic systems

2015

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The Earth's biosphere is dominated by cold environments, and the cold biosphere is dominated by microorganisms. Microorganisms in cold Southern Ocean waters are recognized for having crucial roles in global biogeochemical cycles, including carbon sequestration, whereas microorganisms in other Antarctic aquatic biomes are not as well understood. In this Review, I consider what has been learned about Antarctic aquatic microbial ecology from 'omic' studies. I assess the factors that shape the biogeography of Antarctic microorganisms, reflect on some of the unusual biogeochemical cycles that they are associated with and discuss the important roles that viruses have in controlling ecosystem function.

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Section: Resultsmentioning

confidence: 99%

Microbial ecology of Antarctic aquatic systems

2015

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“…3a, Table S2). At 2.5 m depth, high irradiance and super-saturated oxygen concentrations may activate photorespiratory pathways, as observed for Nodularia, a cyanobacterium forming summer surface blooms in the Baltic (Kopf et al 2015). Other transcripts enriched in the 2.5 m sample were related to glutathione metabolism, terpenoid and peptidoglycan biosynthesis, aminoacyl-tRNA biosynthesis, protein export (signal recognition particle), and to isocitrate dehydrogenase (an enzyme involved in carbon metabolism) (Fig.…”

Section: Cyanobacteriamentioning

confidence: 73%

Winter mixing impacts gene expression in marine microbial populations in the Gulf of Aqaba

Miller¹,

Pfreundt²,

Hou³

et al. 2017

Aquat. Microb. Ecol.

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In aquatic systems, changes in temperature and irradiance fundamentally characterize the water column and regulate microbial population structure and function. In systems with stable thermal stratification, the warm surface mixed layer is typically nutrient impoverished, limiting biological production. In periods of destratification, convective mixing of the water column exposes the microorganisms inhabiting these mixed systems to rapid variations in light availability and spectra. We explored the impact of winter deep-mixing (500 m deep mixed layer) on microbial communities from the surface (2.5 m) and the aphotic waters (440 m) in the Gulf of Aqaba by examining changes in both population composition and function via DNA and RNA sequencing. The greatest fraction of 16S sequences was assigned to Euryarchaeota, while metatranscriptomes were dominated by Synechococcus transcripts. Community composition was highly similar at both depths, yet transcription profiles differed. Phototrophic organisms found at the photic surface overexpressed genes related to catabolism and energy metabolism, while genes affiliated with biosynthesis were overexpressed at the aphotic depth. Similar transcriptional trends were observed in the non-photoautotrophs SAR11, Euryarchaeota, and Thaumarchaeota, with niche partitioning based on differential utilization of nitrogen and phosphorus occurring between the 2 archaeal groups. We did not detect upregulated expression of cyanobacterial genes indicative of mixotrophy or glycogen metabolism in the aphotic zone, suggesting they survive the aphotic period by utilizing photosynthates produced in the photic zone. Indications for a mixotrophic lifestyle were observed for prasinophytes, with genes related to phagocytosis overexpressed at the aphotic depth compared with the surface.

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“…While the reason for this is not clear, the most highly expressed transposase family in our data set was IS200/IS605 ( Figure 6a ), a family that uses an unusual site-specific (3’ to the tetranucleotide TTAC) transposition mechanism ( Ton-Hoang et al , 2010 ). The majority of these transposases were annotated to the filamentous nitrogen-fixing cyanobacterial order Nostocales, in line with such transposases being highly expressed in the Baltic Sea bloom-forming Nodularia spumigena in response to high light and oxygen ( Kopf et al , 2015 ). Moreover, an anti-sense transcript originating from an IS200 transposase incapable of transposition, was found to be involved in regulating up to 30 host genes in Salmonella ( Ellis and Haniford, 2016 ).…”

Section: Discussionmentioning

confidence: 84%

High abundance and expression of transposases in bacteria from the Baltic Sea

et al. 2017

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Transposases are mobile genetic elements suggested to have an important role in bacterial genome plasticity and host adaptation but their transcriptional activity in natural bacterial communities is largely unexplored. Here we analyzed metagenomes and -transcriptomes of size fractionated (0.1–0.8, 0.8–3.0 and 3.0–200 μm) bacterial communities from the brackish Baltic Sea, and adjacent marine waters. The Baltic Sea transposase levels, up to 1.7% of bacterial genes and 2% of bacterial transcripts, were considerably higher than in marine waters and similar to levels reported for extreme environments. Large variations in expression were found between transposase families and groups of bacteria, with a two-fold higher transcription in Cyanobacteria than in any other phylum. The community-level results were corroborated at the genus level by Synechococcus transposases reaching up to 5.2% of genes and 6.9% of transcripts, which is in contrast to marine Synechococcus that largely lack these genes. Levels peaked in Synechococcus from the largest size fraction, suggesting high frequencies of lateral gene transfer and high genome plasticity in colony-forming picocyanobacteria. Together, the results support an elevated rate of transposition-based genome change and adaptation in bacterial populations of the Baltic Sea, and possibly also of other highly dynamic estuarine waters.

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Expression profiling of the bloom-forming cyanobacterium Nodularia CCY9414 under light and oxidative stress conditions

Cited by 31 publications

References 48 publications

Microbial ecology of Antarctic aquatic systems

Microbial ecology of Antarctic aquatic systems

Winter mixing impacts gene expression in marine microbial populations in the Gulf of Aqaba

High abundance and expression of transposases in bacteria from the Baltic Sea

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