| 1. |
- Bunse, Carina, et al.
(författare)
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Response of marine bacterioplankton pH homeostasis gene expression to elevated CO2
- 2016
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Ingår i: Nature Climate Change. - : Macmillan Publishers Ltd.. - 1758-678X .- 1758-6798. ; 6:5, s. 483-487
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Tidskriftsartikel (refereegranskat)abstract
- Human-induced ocean acidification impacts marine life. Marine bacteria are major drivers of biogeochemical nutrient cycles and energy fluxes1; hence, understanding their performance under projected climate change scenarios is crucial for assessing ecosystem functioning. Whereas genetic and physiological responses of phytoplankton to ocean acidification are being disentangled2, 3, 4, corresponding functional responses of bacterioplankton to pH reduction from elevated CO2 are essentially unknown. Here we show, from metatranscriptome analyses of a phytoplankton bloom mesocosm experiment, that marine bacteria responded to lowered pH by enhancing the expression of genes encoding proton pumps, such as respiration complexes, proteorhodopsin and membrane transporters. Moreover, taxonomic transcript analysis showed that distinct bacterial groups expressed different pH homeostasis genes in response to elevated CO2. These responses were substantial for numerous pH homeostasis genes under low-chlorophyll conditions (chlorophyll a <2.5 μg l−1); however, the changes in gene expression under high-chlorophyll conditions (chlorophyll a >20 μg l−1) were low. Given that proton expulsion through pH homeostasis mechanisms is energetically costly, these findings suggest that bacterioplankton adaptation to ocean acidification could have long-term effects on the economy of ocean ecosystems.
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| 2. |
- Delgadillo-Nuno, Erick, et al.
(författare)
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Coastal upwelling systems as dynamic mosaics of bacterioplankton functional specialization
- 2024
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Ingår i: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Coastal upwelling areas are extraordinarily productive environments where prokaryotic communities, the principal remineralizers of dissolved organic matter (DOM), rapidly respond to phytoplankton bloom and decay dynamics. Nevertheless, the extent of variability of key microbial functions in such dynamic waters remains largely unconstrained. Our metatranscriptomics analyses of 162 marker genes encoding ecologically relevant prokaryotic functions showed distinct spatial-temporal patterns in the NW Iberian Peninsula upwelling area. Short-term (daily) changes in specific bacterial functions associated with changes in biotic and abiotic factors were superimposed on seasonal variability. Taxonomic and functional specialization of prokaryotic communities, based mostly on different resource acquisition strategies, was observed. Our results uncovered the potential influence of prokaryotic functioning on phytoplankton bloom composition and development (e.g., Cellvibrionales and Flavobacteriales increased relative gene expression related to vitamin B12 and siderophore metabolisms during Chaetoceros and Dinophyceae summer blooms). Notably, bacterial adjustments to C- or N-limitation and DMSP availability during summer phytoplankton blooms and different spatial-temporal patterns of variability in the expression of genes with different phosphate affinity indicated a complex role of resource availability in structuring bacterial communities in this upwelling system. Also, a crucial role of Cellvibrionales in the degradation of DOM (carbohydrate metabolism, TCA cycle, proteorhodopsin, ammonium, and phosphate uptake genes) during the summer phytoplankton bloom was found. Overall, this dataset revealed an intertwined mosaic of microbial interactions and nutrient utilization patterns along a spatial-temporal gradient that needs to be considered if we aim to understand the biogeochemical processes in some of the most productive ecosystems in the world ' s oceans.
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| 3. |
- Hogfors-Ronnholm, Eva, et al.
(författare)
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Gallionella and Sulfuricella populations are dominant during the transition of boreal potential to actual acid sulfate soils
- 2022
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Ingår i: Communications Earth & Environment. - : Springer Nature. - 2662-4435. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Acid sulfate soils release metal laden, acidic waters that affect the environment, buildings, and human health. In this study, 16S rRNA gene amplicons, metagenomes, and metatranscriptomes all demonstrated distinct microbial communities and activities in the unoxidized potential acid sulfate soil, the overlying transition zone, and uppermost oxidized actual acid sulfate soil. Assembled genomes and mRNA transcripts also suggested abundant oxidized acid sulfate soil populations that aligned within the Gammaproteobacteria and Terracidiphilus. In contrast, potentially acid tolerant or moderately acidophilic iron oxidizing Gallionella and sulfur metabolizing Sulfuricella dominated the transition zone during catalysis of metal sulfide oxidation to form acid sulfate soil. Finally, anaerobic oxidation of methane coupled to nitrate, sulfate, and ferric reduction were suggested to occur in the reduced parent sediments. In conclusion, despite comparable metal sulfide dissolution processes e.g., biomining, Gallionella and Sulfuricella dominated the community and activities during conversion of potential to actual acid sulfate soils.
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| 4. |
- Högfors-Rönnholm, Eva, et al.
(författare)
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Metagenomes and metatranscriptomes from boreal potential and actual acid sulfate soil materials
- 2019
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Ingår i: Scientific Data. - : Nature Publishing Group. - 2052-4463. ; 6, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Natural sulfide rich deposits are common in coastal areas worldwide, including along the Baltic Sea coast. When artificial drainage exposes these deposits to atmospheric oxygen, iron sulfide minerals in the soils are rapidly oxidized. This process turns the potential acid sulfate soils into actual acid sulfate soils and mobilizes large quantities of acidity and leachable toxic metals that cause severe environmental problems. It is known that acidophilic microorganisms living in acid sulfate soils catalyze iron sulfide mineral oxidation. However, only a few studies regarding these communities have been published. In this study, we sampled the oxidized actual acid sulfate soil, the transition zone where oxidation is actively taking place, and the deepest un-oxidized potential acid sulfate soil. Nucleic acids were extracted and 16S rRNA gene amplicons, metagenomes, and metatranscriptomes generated to gain a detailed insight into the communities and their activities. The project will be of great use to microbiologists, environmental biologists, geochemists, and geologists as there is hydrological and geochemical monitoring from the site stretching back for many years.
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| 5. |
- Joglar, Vanessa, et al.
(författare)
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Cobalamin and microbial plankton dynamics along a coastal to offshore transect in the Eastern North Atlantic Ocean
- 2021
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Ingår i: Environmental Microbiology. - : John Wiley & Sons. - 1462-2912 .- 1462-2920. ; 23:3, s. 1559-1583
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Tidskriftsartikel (refereegranskat)abstract
- Cobalamin (B12) is an essential cofactor that is exclusively synthesized by some prokaryotes while many prokaryotes and eukaryotes require an external supply of B12. The spatial and temporal availability of B12 is poorly understood in marine ecosystems. Field measurements of B12 along with a large set of ancillary biotic and abiotic factors were obtained during three oceanographic cruises in the NW Iberian Peninsula, covering different spatial and temporal scales. B12 concentrations were remarkably low (<1.5 pM) in all samples, being significantly higher at the subsurface Eastern North Atlantic Central Water than at shallower depths, suggesting that B12 supply in this water mass is greater than demand. Multiple regression models excluded B12 concentration as predictive variable for phytoplankton biomass or production, regardless of the presence of B12-requiring algae. Prokaryote production was the best predictor for primary production, and eukaryote community composition was better correlated with prokaryote community composition than with nutritional resources, suggesting that biotic interactions play a significant role in regulating microbial communities. Interestingly, co-occurrence network analyses based on 16S and 18S rRNA sequences allowed the identification of significant associations between potential B12 producers and consumers (e.g. Thaumarchaeota and Dynophyceae, or Amylibacter and Ostreococcus respectively), which can now be investigated using model systems in the laboratory.
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| 6. |
- Joglar, Vanessa, et al.
(författare)
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Microbial Plankton Community Structure and Function Responses to Vitamin B-12 and B-1 Amendments in an Upwelling System
- 2021
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Ingår i: Applied and Environmental Microbiology. - : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 87:22
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Tidskriftsartikel (refereegranskat)abstract
- B vitamins are essential cofactors for practically all living organisms on Earth and are produced by a selection of microorganisms. An imbalance between high demand and limited production, in concert with abiotic processes, may explain the low availability of these vitamins in marine systems. Natural microbial communities from surface shelf water in the productive area off northwestern Spain were enclosed in mesocosms in winter, spring, and summer 2016. In order to explore the impact of B-vitamin availability on microbial community composition (16S and 18S rRNA gene sequence analysis) and bacterial function (metatranscriptomics analysis) in different seasons, enrichment experiments were conducted with seawater from the mesocosms. Our findings revealed that significant increases in phytoplankton or prokaryote biomass associated with vitamin B-12 and/or B-1 amendments were not accompanied by significant changes in community composition, suggesting that most of the microbial taxa benefited from the external B-vitamin supply. Metatranscriptome analysis suggested that many bacteria were potential consumers of vitamins B-12 and B-1, although the relative abundance of reads related to synthesis was ca. 3.6-fold higher than that related to uptake. Alteromonadales and Oceanospirillales accounted for important portions of vitamin B-1 and B-12 synthesis gene transcription, despite accounting for only minor portions of the bacterial community. Flavobacteriales appeared to be involved mostly in vitamin B-12 and B-1 uptake, and Pelagibacterales expressed genes involved in vitamin B-1 uptake. Interestingly, the relative expression of vitamin B-12 and B-1 synthesis genes among bacteria strongly increased upon inorganic nutrient amendment. Collectively, these findings suggest that upwelling events intermittently occurring during spring and summer in productive ecosystems may ensure an adequate production of these cofactors to sustain high levels of phytoplankton growth and biomass. IMPORTANCE B vitamins are essential growth factors for practically all living organisms on Earth that are produced by a selection of microorganisms. An imbalance between high demand and limited production may explain the low concentration of these compounds in marine systems. In order to explore the impact of B-vitamin availability on bacteria and algae in the coastal waters off northwestern Spain, six experiments were conducted with natural surface water enclosed in winter, spring, and summer. Our findings revealed that increases in phytoplankton or bacterial growth associated with B-12 and/or B-1 amendments were not accompanied by significant changes in community composition, suggesting that most microorganisms benefited from the B-vitamin supply. Our analyses confirmed the role of many bacteria as consumers of vitamins B-12 and B-1, although the relative abundance of genes related to synthesis was ca. 3.6-fold higher than that related to uptake. Interestingly, prokaryote expression of B-12 and B-1 synthesis genes strongly increased when inorganic nutrients were added. Collectively, these findings suggest that upwelling of cold and nutrient-rich waters occurring during spring and summer in this coastal area may ensure an adequate production of B vitamins to sustain high levels of algae growth and biomass.
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| 7. |
- Lagerqvist, Bo, et al.
(författare)
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Outcomes 1 year after thrombus aspiration for myocardial infarction.
- 2014
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Ingår i: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 371:12, s. 1111-1120
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Tidskriftsartikel (refereegranskat)abstract
- Routine intracoronary thrombus aspiration before primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) has not been proved to reduce short-term mortality. We evaluated clinical outcomes at 1 year after thrombus aspiration.
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| 8. |
- Lundin, Daniel, et al.
(författare)
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Which sequencing depth is sufficient to describe patterns in bacterial alpha- and beta-diversity?
- 2012
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Ingår i: Environmental Microbiology Reports. - : Wiley. - 1758-2229. ; 4:3, s. 367-372
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Tidskriftsartikel (refereegranskat)abstract
- The vastness of microbial diversity implies that an almost infinite number of individuals needs to be identified to accurately describe such communities. Practical and economical constraints may therefore prevent appropriate study designs. However, for many questions in ecology it is not essential to know the actual diversity but rather the trends among samples thereof. It is, hence, important to know to what depth microbial communities need to be sampled to accurately measure trends in diversity. We used three data sets of freshwater and sediment bacteria, where diversity was explored using 454 pyrosequencing. Each data set contained 615 communities from which 15 00020 000 16S rRNA gene sequences each were obtained. These data sets were subsampled repeatedly to 10 different depths down to 200 sequences per community. Diversity estimates varied with sequencing depth, yet, trends in diversity among samples were less sensitive. We found that 1000 denoised sequences per sample explained to 90% the trends in beta-diversity (Bray-Curtis index) among samples observed for 15 00020 000 sequences. Similarly, 5000 denoised sequences were sufficient to describe trends in a-diversity (Shannon index) with the same accuracy. Further, 5000 denoised sequences captured to more than 80% the trends in Chao1 richness and Pielou's evenness.
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| 9. |
- Pinhassi, Jarone, et al.
(författare)
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Functional responses of key marine bacteria to environmental change - toward genetic counselling for coastal waters
- 2022
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Coastal ecosystems deteriorate globally due to human-induced stress factors, like nutrient loading and pollution. Bacteria are critical to marine ecosystems, e.g., by regulating nutrient cycles, synthesizing vitamins, or degrading pollutants, thereby providing essential ecosystem services ultimately affecting economic activities. Yet, until now bacteria are overlooked both as mediators and indicators of ecosystem health, mainly due to methodological limitations in assessing bacterial ecosystem functions. However, these limitations are largely overcome by the advances in molecular biology and bioinformatics methods for characterizing the genetics that underlie functional traits of key bacterial populations - "key" in providing important ecosystem services, being abundant, or by possessing high metabolic rates. It is therefore timely to analyze and define the functional responses of bacteria to human-induced effects on coastal ecosystem health. We posit that categorizing the responses of key marine bacterial populations to changes in environmental conditions through modern microbial oceanography methods will allow establishing the nascent field of genetic counselling for our coastal waters. This requires systematic field studies of linkages between functional traits of key bacterial populations and their ecosystem functions in coastal seas, complemented with systematic experimental analyses of the responses to different stressors. Research and training in environmental management along with dissemination of results and dialogue with societal actors are equally important to ensure the role of bacteria is understood as fundamentally important for coastal ecosystems. Using the responses of microorganisms as a tool to develop genetic counselling for coastal ecosystems can ultimately allow for integrating bacteria as indicators of environmental change.
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| 10. |
- Pontiller, Benjamin, MSc, 1985-, et al.
(författare)
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Rapid bacterioplankton transcription cascades regulate organic matter utilization during phytoplankton bloom progression in a coastal upwelling system
- 2022
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Ingår i: The ISME Journal. - : Nature Publishing Group. - 1751-7362 .- 1751-7370. ; 16, s. 2360-2372
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Tidskriftsartikel (refereegranskat)abstract
- Coastal upwelling zones are veritable hotspots of oceanic productivity, driven by phytoplankton photosynthesis. Bacteria, in turn, grow on and are the principal remineralizers of dissolved organic matter (DOM) produced in aquatic ecosystems. However, knowledge of the molecular processes that key bacterial taxa employ to regulate the turnover of phytoplankton-derived DOM has yet to advance. We therefore carried out a comparative metatranscriptomics analysis with parallel sampling of bacterioplankton during experimental and natural phytoplankton blooms in the Northwest Iberian upwelling system. The experiment analysis uncovered a taxon-specific progression of transcriptional responses from bloom development, over early decay, to senescence phases. This included pronounced order-specific differences in regulation of glycoside hydrolases and peptidases along with transporters, supporting the notion that functional resource partitioning is dynamically structured by temporal changes in available DOM. In addition, comparative analysis of experiment and field blooms revealed a large degree of metabolic plasticity in the degradation and uptake of carbohydrates and nitrogen-rich compounds, suggesting these gene systems critically contribute to modulating the stoichiometry of the coastal DOM pool. Collectively, our findings suggest that cascades of transcriptional responses in gene systems for the utilization of organic matter and nutrients largely shape the fate of organic matter on the short time scales typical of upwelling-driven phytoplankton blooms.
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