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  • 1.
    Alneberg, Johannes
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Bioinformatic Methods in Metagenomics2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Microbial organisms are a vital part of our global ecosystem. Yet, our knowledge of them is still lacking. Direct sequencing of microbial communities, i.e. metagenomics, have enabled detailed studies of these microscopic organisms by inspection of their DNA sequences without the need to culture them. Furthermore, the development of modern high- throughput sequencing technologies have made this approach more powerful and cost-effective. Taken together, this has shifted the field of microbiology from previously being centered around microscopy and culturing studies, to largely consist of computational analyses of DNA sequences. One such computational analysis which is the main focus of this thesis, aims at reconstruction of the complete DNA sequence of an organism, i.e. its genome, directly from short metagenomic sequences.

    This thesis consists of an introduction to the subject followed by five papers. Paper I describes a large metagenomic data resource spanning the Baltic Sea microbial communities. This dataset is complemented with a web-interface allowing researchers to easily extract and visualize detailed information. Paper II introduces a bioinformatic method which is able to reconstruct genomes from metagenomic data. This method, which is termed CONCOCT, is applied on Baltic Sea metagenomics data in Paper III and Paper V. This enabled the reconstruction of a large number of genomes. Analysis of these genomes in Paper III led to the proposal of, and evidence for, a global brackish microbiome. Paper IV presents a comparison between genomes reconstructed from metagenomes with single-cell sequenced genomes. This further validated the technique presented in Paper II as it was found to produce larger and more complete genomes than single-cell sequencing.

  • 2.
    Alneberg, Johannes
    et al.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi.
    Bennke, Christin
    Leibniz Institute for Baltic Sea Research, Warnemünde, Germany.
    Beier, Sara
    Leibniz Institute for Baltic Sea Research, Warnemünde, Germany.
    Pinhassi, Jarone
    Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
    Jürgens, Klaus
    Leibniz Institute for Baltic Sea Research, Warnemünde, Germany.
    Ekman, Martin
    Department of Ecology, Environment and Plant Sciences, Stockholm University Science for Life Laboratory, Solna, Sweden.
    Ininbergs, Karolina
    Department of Ecology, Environment and Plant Sciences, Stockholm University Science for Life Laboratory, Solna, Sweden.
    Labrenz, Matthias
    Leibniz Institute for Baltic Sea Research, Warnemünde, Germany.
    Andersson, Anders F.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi.
    Recovering 2,032 Baltic Sea microbial genomes by optimized metagenomic binningManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Aquatic microorganism are key drivers of global biogeochemical cycles and form the basis of aquatic food webs. However, there is still much left to be learned about these organisms and their interaction within specific environments, such as the Baltic Sea. Crucial information for such an understanding can be found within the genome sequences of organisms within the microbial community.

    In this study, the previous set of Baltic Sea clusters, constructed by Hugert et al., is greatly expanded using a large set of metagenomic samples, spanning the environmental gradients of the Baltic Sea. In total, 124 samples were individually assembled and binned to obtain 2,032 Metagenome Assembled Genomes (MAGs), clustered into 353 prokaryotic and 14 eukaryotic species- level clusters. The prokaryotic genomes were widely distributed over the prokaryotic tree of life, representing 20 different phyla, while the eukaryotic genomes were mostly limited to the division of Chlorophyta. The large number of reconstructed genomes allowed us to identify key factors determining the quality of the genome reconstructions.

    The Baltic Sea is heavily influenced of human activities of which we might not see the full implications. The genomes reported within this study will greatly aid further studies in our strive for an understanding of the Baltic Sea microbial ecosystem.

  • 3.
    Alneberg, Johannes
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Karlsson, Christofer M. G.
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst, EEMiS, Kalmar, Sweden..
    Divne, Anna-Maria
    Uppsala Univ, Dept Cell & Mol Biol, SciLifeLab, Uppsala, Sweden..
    Bergin, Claudia
    Uppsala Univ, Dept Cell & Mol Biol, SciLifeLab, Uppsala, Sweden..
    Homa, Felix
    Uppsala Univ, Dept Cell & Mol Biol, SciLifeLab, Uppsala, Sweden..
    Lindh, Markus V.
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst, EEMiS, Kalmar, Sweden.;Lund Univ, Dept Biol, Lund, Sweden..
    Hugerth, Luisa
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Ettema, Thijs J. G.
    Uppsala Univ, Dept Cell & Mol Biol, SciLifeLab, Uppsala, Sweden..
    Bertilsson, Stefan
    Uppsala Univ, Dept Ecol & Genet, Sci Life Lab, Limnol, Uppsala, Sweden..
    Andersson, Anders F.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Pinhassi, Jarone
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst, EEMiS, Kalmar, Sweden..
    Genomes from uncultivated prokaryotes: a comparison of metagenome-assembled and single-amplified genomes2018Inngår i: Microbiome, ISSN 0026-2633, E-ISSN 2049-2618, Vol. 6, artikkel-id 173Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Prokaryotes dominate the biosphere and regulate biogeochemical processes essential to all life. Yet, our knowledge about their biology is for the most part limited to the minority that has been successfully cultured. Molecular techniques now allow for obtaining genome sequences of uncultivated prokaryotic taxa, facilitating in-depth analyses that may ultimately improve our understanding of these key organisms. Results: We compared results from two culture-independent strategies for recovering bacterial genomes: single-amplified genomes and metagenome-assembled genomes. Single-amplified genomes were obtained from samples collected at an offshore station in the Baltic Sea Proper and compared to previously obtained metagenome-assembled genomes from a time series at the same station. Among 16 single-amplified genomes analyzed, seven were found to match metagenome-assembled genomes, affiliated with a diverse set of taxa. Notably, genome pairs between the two approaches were nearly identical (average 99.51% sequence identity; range 98.77-99.84%) across overlapping regions (30-80% of each genome). Within matching pairs, the single-amplified genomes were consistently smaller and less complete, whereas the genetic functional profiles were maintained. For the metagenome-assembled genomes, only on average 3.6% of the bases were estimated to be missing from the genomes due to wrongly binned contigs. Conclusions: The strong agreement between the single-amplified and metagenome-assembled genomes emphasizes that both methods generate accurate genome information from uncultivated bacteria. Importantly, this implies that the research questions and the available resources are allowed to determine the selection of genomics approach for microbiome studies.

  • 4.
    Alneberg, Johannes
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Karlsson, Christofer M.G.
    Centre for Ecology and Evolution in Microbial Model Systems, EEMiS, Linnaeus University, Barlastgatan 11, 391 82 Kalmar, Sweden.
    Divne, Anna-Maria
    Department of Cell and Molecular Biology, SciLifeLab, Uppsala University, Uppsala, Sweden .
    Bergin, Claudia
    Department of Cell and Molecular Biology, SciLifeLab, Uppsala University, Uppsala, Sweden .
    Homa, Felix
    Department of Cell and Molecular Biology, SciLifeLab, Uppsala University, Uppsala, Sweden .
    Lindh, Markus V.
    Centre for Ecology and Evolution in Microbial Model Systems, EEMiS, Linnaeus University, Barlastgatan 11, 391 82 Kalmar, Sweden.
    Hugerth, Luisa W.
    Karolinska Institutet, Science for Life Laboratory, Department of Molecular, Tumour and Cell Biology, Centre for Translational Microbiome Research, Solna, Sweden.
    Ettema, Thijs JG
    Department of Cell and Molecular Biology, SciLifeLab, Uppsala University, Uppsala, Sweden.
    Bertilsson, Stefan
    Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
    Andersson, Anders F.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi.
    Pinhassi, Jarone
    Centre for Ecology and Evolution in Microbial Model Systems, EEMiS, Linnaeus University, Barlastgatan 11, 391 82 Kalmar, Sweden.
    Genomes from uncultivated prokaryotes: a comparison of metagenome-assembled and single-amplified genomesManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Background: Prokaryotes dominate the biosphere and regulate biogeochemical processes essential to all life. Yet, our knowledge about their biology is for the most part limited to the minority that has been successfully cultured. Molecular techniques now allow for obtaining genome sequences of uncultivated prokaryotic taxa, facilitating in-depth analyses that may ultimately improve our understanding of these key organisms.

    Results: We compared results from two culture-independent strategies for recovering bacterial genomes: single-amplified genomes and metagenome-assembled genomes. Single-amplified genomes were obtained from samples collected at an offshore station in the Baltic Sea Proper and compared to previously obtained metagenome-assembled genomes from a time series at the same station. Among 16 single-amplified genomes analyzed, seven were found to match metagenome-assembled genomes, affiliated with a diverse set of taxa. Notably, genome pairs between the two approaches were nearly identical (>98.7% identity) across overlapping regions (30-80% of each genome). Within matching pairs, the single-amplified genomes were consistently smaller and less complete, whereas the genetic functional profiles were maintained. For the metagenome-assembled genomes, only on average 3.6% of the bases were estimated to be missing from the genomes due to wrongly binned contigs; the metagenome assembly was found to cause incompleteness to a higher degree than the binning procedure.

    Conclusions: The strong agreement between the single-amplified and metagenome-assembled genomes emphasizes that both methods generate accurate genome information from uncultivated bacteria. Importantly, this implies that the research questions and the available resources are allowed to determine the selection of genomics approach for microbiome studies.

  • 5.
    Alneberg, Johannes
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Sundh, John
    Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.
    Bennke, Christin
    Leibniz Institute for Baltic Sea Research, Warnemünde, Germany.
    Beier, Sara
    Leibniz Institute for Baltic Sea Research, Warnemünde, Germany.
    Lundin, Daniel
    Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
    Hugerth, Luisa
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för bioteknologi (BIO).
    Pinhassi, Jarone
    Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
    Kisand, Veljo
    University of Tartu, Institute of Technology, Tartu, Estonia.
    Riemann, Lasse
    Section for Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
    Jürgens, Klaus
    Leibniz Institute for Baltic Sea Research, Warnemünde, Germany.
    Labrenz, Matthias
    Leibniz Institute for Baltic Sea Research, Warnemünde, Germany.
    Andersson, Anders F.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    BARM and BalticMicrobeDB, a reference metagenome and interface to meta-omic data for the Baltic SeaManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The Baltic Sea is one of the world’s largest brackish water bodies and is characterised by pronounced physicochemical gradients where microbes are the main biogeochemical catalysts. Meta-omic methods provide rich information on the composition of, and activities within microbial ecosystems, but are computationally heavy to perform. We here present the BAltic Sea Reference Metagenome (BARM), complete with annotated genes to facilitate further studies with much less computational effort. The assembly is constructed using 2.6 billion metagenomic reads from 81 water samples, spanning both spatial and temporal dimensions, and contains 6.8 million genes that have been annotated for function and taxonomy. The assembly is useful as a reference, facilitating taxonomic and functional annotation of additional samples by simply mapping their reads against the assembly. This capability is demonstrated by the successful mapping and annotation of 24 external samples. In addition, we present a public web interface, BalticMicrobeDB, for interactive exploratory analysis of the dataset.

  • 6.
    Alneberg, Johannes
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Sundh, John
    Stockholm Univ, Sci Life Lab, Dept Biochem & Biophys, S-17165 Solna, Sweden..
    Bennke, Christin
    Leibniz Inst Balt Sea Res Warnemunde, D-18119 Rostock, Germany..
    Beier, Sara
    Leibniz Inst Balt Sea Res Warnemunde, D-18119 Rostock, Germany..
    Lundin, Daniel
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst, S-39182 Kalmar, Sweden..
    Hugerth, Luisa W.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab. Karolinska Inst, Dept Mol Tumor & Cell Biol, Ctr Translat Microbiome Res, Sci Life Lab, S-17165 Solna, Sweden..
    Pinhassi, Jarone
    Linnaeus Univ, Ctr Ecol & Evolut Microbial Model Syst, S-39182 Kalmar, Sweden..
    Kisand, Veljo
    Univ Tartu, Inst Technol, EE-50411 Tartu, Estonia..
    Riemann, Lasse
    Univ Copenhagen, Sect Marine Biol Sect, Dept Biol, DK-3000 Helsingor, Denmark..
    Juergens, Klaus
    Leibniz Inst Balt Sea Res Warnemunde, D-18119 Rostock, Germany..
    Labrenz, Matthias
    Leibniz Inst Balt Sea Res Warnemunde, D-18119 Rostock, Germany..
    Andersson, Anders F.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    BARM and BalticMicrobeDB, a reference metagenome and interface to meta-omic data for the Baltic Sea2018Inngår i: Scientific Data, E-ISSN 2052-4463, Vol. 5, artikkel-id 180146Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Baltic Sea is one of the world's largest brackish water bodies and is characterised by pronounced physicochemical gradients where microbes are the main biogeochemical catalysts. Meta-omic methods provide rich information on the composition of, and activities within, microbial ecosystems, but are computationally heavy to perform. We here present the Baltic Sea Reference Metagenome (BARM), complete with annotated genes to facilitate further studies with much less computational effort. The assembly is constructed using 2.6 billion metagenomic reads from 81 water samples, spanning both spatial and temporal dimensions, and contains 6.8 million genes that have been annotated for function and taxonomy. The assembly is useful as a reference, facilitating taxonomic and functional annotation of additional samples by simply mapping their reads against the assembly. This capability is demonstrated by the successful mapping and annotation of 24 external samples. In addition, we present a public web interface, BalticMicrobeDB, for interactive exploratory analysis of the dataset.

  • 7. Bell, E.
    et al.
    Lamminmäki, T.
    Alneberg, Johannes
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi.
    Andersson, Anders F.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi.
    Qian, C.
    Xiong, W.
    Hettich, R. L.
    Balmer, L.
    Frutschi, M.
    Sommer, G.
    Bernier-Latmani, R.
    Biogeochemical cycling by a low-diversity microbial community in deep groundwater2018Inngår i: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 9, nr SEP, artikkel-id 2129Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Olkiluoto, an island on the south-west coast of Finland, will host a deep geological repository for the storage of spent nuclear fuel. Microbially induced corrosion from the generation of sulphide is therefore a concern as it could potentially compromise the longevity of the copper waste canisters. Groundwater at Olkiluoto is geochemically stratified with depth and elevated concentrations of sulphide are observed when sulphate-rich and methane-rich groundwaters mix. Particularly high sulphide is observed in methane-rich groundwater from a fracture at 530.6 mbsl, where mixing with sulphate-rich groundwater occurred as the result of an open drill hole connecting two different fractures at different depths. To determine the electron donors fuelling sulphidogenesis, we combined geochemical, isotopic, metagenomic and metaproteomic analyses. This revealed a low diversity microbial community fuelled by hydrogen and organic carbon. Sulphur and carbon isotopes of sulphate and dissolved inorganic carbon, respectively, confirmed that sulphate reduction was ongoing and that CO2 came from the degradation of organic matter. The results demonstrate the impact of introducing sulphate to a methane-rich groundwater with limited electron acceptors and provide insight into extant metabolisms in the terrestrial subsurface. 

  • 8.
    Charvet, Sophie
    et al.
    IOW Leibniz Inst Balt Sea Res, Warnemunde, Germany..
    Riemann, Lasse
    Univ Copenhagen, Marine Biol Sect, Dept Biol, Copenhagen, Denmark..
    Alneberg, Johannes
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Andersson, Anders F.
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    von Borries, Julian
    HYDRO BIOS Apparatebau GmbH, Altenholz, Germany..
    Fischer, Uwe
    HYDRO BIOS Apparatebau GmbH, Altenholz, Germany..
    Labrenz, Matthias
    IOW Leibniz Inst Balt Sea Res, Warnemunde, Germany..
    AFISsys - An autonomous instrument for the preservation of brackish water samples for microbial metatranscriptome analysis2019Inngår i: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 149, s. 351-361Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microbial communities are the main drivers of biogeochemical cycling of multiple elements sustaining life in the ocean. The rapidity of their response to stressors and abrupt environmental changes implies that even fast and infrequent events can affect local transformations of organic matter and nutrients. Modern molecular techniques now allow for monitoring of microbial activities and functions in the environment through the analysis of genes and expressed genes contained in natural microbial assemblages. However, messenger RNA turnover in cells can be as short as 30 seconds and stability varies greatly between transcripts. Sampling of in situ communities involves an inevitable delay between the collection of seawater and the extraction of its RNA, leaving the bacterial communities plenty of time to alter their gene expression. The characteristics of microbial RNA turnover make time-series very difficult because samples need to be processed immediately to limit alterations to the metatranscriptomes. To address these challenges we designed an autonomous in situ fixation multi-sampler (AFISsys) for the reliable sampling of microbial metatranscriptomes at frequent intervals, for refined temporal resolution. To advance the development of this instrument, we examined the minimal seawater volume necessary for adequate coverage of community gene expression, and the suitability of phenol/ethanol fixation for immediate and long-term preservation of transcripts from a microbial community. We then evaluated the field eligibility of the instrument itself, with two case studies in a brackish system. AFISsys is able to collect, fix, and store water samples independently at a predefined temporal resolution. Phenol/ethanol fixation can conserve metatranscriptomes directly in the environment for up to a week, for later analysis in the laboratory. Thus, the AFISsys constitutes an invaluable tool for the integration of molecular functional analyses in environmental monitoring in brackish waters and in aquatic environments in general. 

  • 9. Happel, E. M.
    et al.
    Markussen, T.
    Teikari, J. E.
    Huchaiah, V.
    Alneberg, Johannes
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Andersson, Anders F.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Sivonen, K.
    Middelboe, M.
    Kisand, V.
    Riemann, L.
    Effects of allochthonous dissolved organic matter input on microbial composition and nitrogen-cycling genes at two contrasting estuarine sites2019Inngår i: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 95, nr 9, artikkel-id fiz123Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heterotrophic bacteria are important drivers of nitrogen (N) cycling and the processing of dissolved organic matter (DOM). Projected increases in precipitation will potentially cause increased loads of riverine DOM to the Baltic Sea and likely affect the composition and function of bacterioplankton communities. To investigate this, the effects of riverine DOM from two different catchment areas (agricultural and forest) on natural bacterioplankton assemblages from two contrasting sites in the Baltic Sea were examined. Two microcosm experiments were carried out, where the community composition (16S rRNA gene sequencing), the composition of a suite of N-cycling genes (metagenomics) and the abundance and transcription of ammonia monooxygenase (amoA) genes involved in nitrification (quantitative PCR) were investigated. The river water treatments evoked a significant response in bacterial growth, but the effects on overall community composition and the representation of N-cycling genes were limited. Instead, treatment effects were reflected in the prevalence of specific taxonomic families, specific N-related functions and in the transcription of amoA genes. The study suggests that bacterioplankton responses to changes in the DOM pool are constrained to part of the bacterial community, whereas most taxa remain relatively unaffected.

  • 10.
    Hu, Yue O. O.
    et al.
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Ndegwa, Nelson
    Karolinska Inst, Dept Med Epidemiol & Biostat, Stockholm, Sweden..
    Alneberg, Johannes
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Johansson, Sebastian
    Stockholm Univ, Dept Biochem & Biophys, Sci Life Lab, Stockholm, Sweden..
    Logue, Jurg Brendan
    Huss, Mikael
    Käller, Max
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lundeberg, Joakim
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Fagerberg, Jens
    Stockholm Vatten Och Avfall AB, Stockholm, Sweden..
    Andersson, Anders F.
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Stationary and portable sequencing-based approaches for tracing wastewater contamination in urban stormwater systems2018Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, artikkel-id 11907Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Urban sewer systems consist of wastewater and stormwater sewers, of which only wastewater is processed before being discharged. Occasionally, misconnections or damages in the network occur, resulting in untreated wastewater entering natural water bodies via the stormwater system. Cultivation of faecal indicator bacteria (e.g. Escherichia coli; E. coli) is the current standard for tracing wastewater contamination. This method is cheap but has limited specificity and mobility. Here, we compared the E. coli culturing approach with two sequencing-based methodologies (Illumina MiSeq 16S rRNA gene amplicon sequencing and Oxford Nanopore MinION shotgun metagenomic sequencing), analysing 73 stormwater samples collected in Stockholm. High correlations were obtained between E. coli culturing counts and frequencies of human gut microbiome amplicon sequences, indicating E. coli is indeed a good indicator of faecal contamination. However, the amplicon data further holds information on contamination source or alternatively how much time has elapsed since the faecal matter has entered the system. Shotgun metagenomic sequencing on a subset of the samples using a portable real-time sequencer, MinION, correlated well with the amplicon sequencing data. This study demonstrates the use of DNA sequencing to detect human faecal contamination in stormwater systems and the potential of tracing faecal contamination directly in the field.

  • 11.
    Markussen, Trine
    et al.
    Univ Copenhagen, Dept Biol, Marine Biol Sect, Helsingor, Denmark..
    Happel, Elisabeth M.
    Univ Copenhagen, Dept Biol, Marine Biol Sect, Helsingor, Denmark..
    Teikari, Jonna E.
    Univ Helsinki, Dept Microbiol, Helsinki, Finland..
    Huchaiah, Vimala
    Univ Tartu, Inst Technol, Tartu, Estonia..
    Alneberg, Johannes
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Andersson, Anders F.
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Sivonen, Kaarina
    Univ Helsinki, Dept Microbiol, Helsinki, Finland..
    Riemann, Lasse
    Univ Copenhagen, Dept Biol, Marine Biol Sect, Helsingor, Denmark..
    Middelboe, Mathias
    Univ Copenhagen, Dept Biol, Marine Biol Sect, Helsingor, Denmark..
    Kisand, Veljo
    Univ Tartu, Inst Technol, Tartu, Estonia..
    Coupling biogeochemical process rates and metagenomic blueprints of coastal bacterial assemblages in the context of environmental change2018Inngår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 20, nr 8, s. 3083-3099Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bacteria are major drivers of biogeochemical nutrient cycles and energy fluxes in marine environments, yet how bacterial communities respond to environmental change is not well known. Metagenomes allow examination of genetic responses of the entire microbial community to environmental change. However, it is challenging to link metagenomes directly to biogeochemical process rates. Here, we investigate metagenomic responses in natural bacterioplankton communities to simulated environmental stressors in the Baltic Sea, including increased river water input, increased nutrient concentration, and reduced oxygen level. This allowed us to identify informative prokaryotic gene markers, responding to environmental perturbation. Our results demonstrate that metagenomic and metabolic changes in bacterial communities in response to environmental stressors are influenced both by the initial community composition and by the biogeochemical factors shaping the functional response. Furthermore, the different sources of dissolved organic matter (DOM) had the largest impact on metagenomic blueprint. Most prominently, changes in DOM loads influenced specific transporter types reflecting the substrate availability and DOC assimilation and consumption pathways. The results provide new knowledge for developing models of ecosystem structure and biogeochemical cycling in future climate change scenarios and advance our exploration of the potential use of marine microorganisms as markers for environmental conditions.

  • 12. Quince, Christopher
    et al.
    Delmont, Tom O.
    Raguideau, Sebastien
    Alneberg, Johannes
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Darling, Aaron E.
    Collins, Gavin
    Eren, A. Murat
    DESMAN: a new tool for de novo extraction of strains from metagenomes2017Inngår i: Genome Biology, ISSN 1465-6906, E-ISSN 1474-760X, Vol. 18, artikkel-id 181Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We introduce DESMAN for De novo Extraction of Strains from Metagenomes. Large multi-sample metagenomes are being generated but strain variation results in fragmentary co-assemblies. Current algorithms can bin contigs into metagenome-assembled genomes but are unable to resolve strain-level variation. DESMAN identifies variants in core genes and uses co-occurrence across samples to link variants into haplotypes and abundance profiles. These are then searched for against non-core genes to determine the accessory genome of each strain. We validated DESMAN on a complex 50-species 210-genome 96-sample synthetic mock data set and then applied it to the Tara Oceans microbiome.

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