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  • 1. Ahmed, Engy
    et al.
    Hugerth, Luisa W.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Logue, Jürg Brendan
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Bruchert, Volker
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Holmström, Sara J. M.
    Mineral Type Structures Soil Microbial Communities2017Inngår i: Geomicrobiology Journal, ISSN 0149-0451, E-ISSN 1521-0529, Vol. 34, nr 6, s. 538-545Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soil microorganisms living in close contact with minerals play key roles in the biogeochemical cycling of elements, soil formation, and plant nutrition. Yet, the composition of microbial communities inhabiting the mineralosphere (i.e., the soil surrounding minerals) is poorly understood. Here, we explored the composition of soil microbial communities associated with different types of minerals in various soil horizons. To this effect, a field experiment was set up in which mineral specimens of apatite, biotite, and oligoclase were buried in the organic, eluvial, and upper illuvial horizons of a podzol soil. After an incubation period of two years, the soil attached to the mineral surfaces was collected, and microbial communities were analyzed by means of Illumina MiSeq sequencing of the 16S (prokaryotic) and 18S (eukaryotic) ribosomal RNA genes. We found that both composition and diversity of bacterial, archaeal, and fungal communities varied across the different mineral surfaces, and that mineral type had a greater influence on structuring microbial assemblages than soil horizon. Thus, our findings emphasize the importance of mineral surfaces as ecological niches in soils.

  • 2.
    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.

  • 3.
    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.

  • 4.
    Hugerth, Luisa
    KTH, Skolan för bioteknologi (BIO), Genteknologi. Science for Life Laboratory.
    High-throughput DNA Sequencingin Microbial Ecology: Methods and Applications2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Microorganisms play central roles in planet Earth’s geochemical cycles, in food production, and in health and disease of humans and livestock. In spite of this, most microbial life forms remain unknown and unnamed, their ecological importance and potential technological applications beyond the realm of speculation. This is due both to the magnitude of microbial diversity and to technological limitations. Of the many advances that have enabled microbiology to reach new depth and breadth in the past decade, one of the most important is affordable high-throughput DNA sequencing. This technology plays a central role in each paper in this thesis.

    Papers I and II are focused on developing methods to survey microbial diversity based on marker gene amplification and sequencing. In Paper I we proposed a computational strategy to design primers with the highest coverage among a given set of sequences and applied it to drastically improve one of the most commonly used primer pairs for ecological surveys of prokaryotes. In Paper II this strategy was applied to an eukaryotic marker gene. Despite their importance in the food chain, eukaryotic microbes are much more seldom surveyed than bacteria. Paper II aimed at making this domain of life more amenable to high-throughput surveys.

    In Paper III, the primers designed in papers I and II were applied to water samples collected up to twice weekly from 2011 to 2013 at an offshore station in the Baltic proper, the Linnaeus Microbial Observatory. In addition to tracking microbial communities over these three years, we created predictive models for hundreds of microbial populations, based on their co-occurrence with other populations and environmental factors.

    In paper IV we explored the entire metagenomic diversity in the Linnaeus Microbial Observatory. We used computational tools developed in our group to construct draft genomes of abundant bacteria and archaea and described their phylogeny, seasonal dynamics and potential physiology. We were also able to establish that, rather than being a mixture of genomes from fresh and saline water, the Baltic Sea plankton community is composed of brackish specialists which diverged from other aquatic microorganisms thousands of years before the formation of the Baltic itself.

  • 5.
    Hugerth, Luisa
    et al.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. Science for Life Laboratory.
    Lindh, Markus
    Centre for Ecology and Evolution in Microbial model Systems - Linnaeus University.
    Sjöqvist, Conny
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Carina, Bunse
    Centre for Ecology and Evolution in Microbial model Systems - Linnaeus University.
    Legrand, Catherine
    Centre for Ecology and Evolution in Microbial model Systems - Linnaeus University.
    Pinhassi, Jarone
    Centre for Ecology and Evolution in Microbial model Systems - Linnaeus University.
    Andersson, Anders
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Seasonal dynamics and interactions among Baltic Sea prokaryoticand eukaryotic plankton assemblagesManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    One of the main goals of microbial ecology is to identify the mechanismsthat regulate patterns in community structure at temporal scalescompatible with populations’ turnover times across complete seasonalcycles. Here, we examined high-frequency temporal dynamics of marineplankton from a sampling effort covering 2011-2013, roughly twice weekly,comprising 144 samples. Bacterial and eukaryotic communities wereprofiled by 16S and 18S high-throughput sequencing, respectively.Interestingly, we found that no combination of the measured environmentalparameters could predict a significant proportion of the variation inpopulation dynamics of bacterioplankton, and even less so for eukaryoticplankton. Large differences in physicochemical conditions and communitycomposition typical of temperate climates mean that different regimes canquickly succeed each other over the year, with the relative importance ofdifferent drivers changing equally rapidly. Nevertheless, our approachrevealed interesting recurrent co-occurrence patterns across distinctenvironmental changes. Hence, we could make abundance predictions formore than half of the most frequent OTUs based on interactions with otherOTUs. These results suggests that a complex set of biotic interactions arecontributing to temporal patterns among planktonic assemblages despiterapid changes in environmental conditions.

  • 6.
    Hugerth, Luisa W.
    et al.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab. Karolinska Institutet, Sweden.
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Analysing Microbial Community Composition through Amplicon Sequencing: From Sampling to Hypothesis Testing2017Inngår i: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 8, artikkel-id 1561Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Microbial ecology as a scientific field is fundamentally driven by technological advance. The past decade's revolution in DNA sequencing cost and throughput has made it possible for most research groups to map microbial community composition in environments of interest. However, the computational and statistical methodology required to analyse this kind of data is often not part of the biologist training. In this review, we give a historical perspective on the use of sequencing data inmicrobial ecology and restate the current need for this method; but also highlight the major caveats with standard practices for handling these data, from sample collection and library preparation to statistical analysis. Further, we outline the main new analytical tools that have been developed in the past few years to bypass these caveats, as well as highlight the major requirements of common statistical practices and the extent to which they are applicable to microbial data. Besides delving into the meaning of select alpha- and beta-diversity measures, we give special consideration to techniques for finding the main drivers of community dissimilarity and for interaction network construction. While every project design has specific needs, this review should serve as a starting point for considering what options are available.

  • 7.
    Hugerth, Luisa W.
    et al.
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Larsson, John
    Alneberg, Johannes
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Lindh, Markus V.
    Legrand, Catherine
    Pinhassi, Jarone
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Metagenome-assembled genomes uncover a global brackish microbiome2015Inngår i: Genome Biology, ISSN 1465-6906, E-ISSN 1474-760X, Vol. 16, artikkel-id 279Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Microbes are main drivers of biogeochemical cycles in oceans and lakes. Although the genome is a foundation for understanding the metabolism, ecology and evolution of an organism, few bacterioplankton genomes have been sequenced, partly due to difficulties in cultivating them. Results: We use automatic binning to reconstruct a large number of bacterioplankton genomes from a metagenomic time-series from the Baltic Sea, one of world's largest brackish water bodies. These genomes represent novel species within typical freshwater and marine clades, including clades not previously sequenced. The genomes' seasonal dynamics follow phylogenetic patterns, but with fine-grained lineage-specific variations, reflected in gene-content. Signs of streamlining are evident in most genomes, and estimated genome sizes correlate with abundance variation across filter size fractions. Comparing the genomes with globally distributed metagenomes reveals significant fragment recruitment at high sequence identity from brackish waters in North America, but little from lakes or oceans. This suggests the existence of a global brackish metacommunity whose populations diverged from freshwater and marine relatives over 100,000 years ago, long before the Baltic Sea was formed (8000 years ago). This markedly contrasts to most Baltic Sea multicellular organisms, which are locally adapted populations of freshwater or marine counterparts. Conclusions: We describe the gene content, temporal dynamics and biogeography of a large set of new bacterioplankton genomes assembled from metagenomes. We propose that brackish environments exert such strong selection that lineages adapted to them flourish globally with limited influence from surrounding aquatic communities.

  • 8.
    Hugerth, Luisa W.
    et al.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Muller, Emilie E. L.
    Hu, Yue O. O.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lebrun, Laura A. M.
    Roume, Hugo
    Lundin, Daniel
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Wilmes, Paul
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Systematic Design of 18S rRNA Gene Primers for Determining Eukaryotic Diversity in Microbial Consortia2014Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 4, s. 095567-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High-throughput sequencing of ribosomal RNA gene (rDNA) amplicons has opened up the door to large-scale comparative studies of microbial community structures. The short reads currently produced by massively parallel sequencing technologies make the choice of sequencing region crucial for accurate phylogenetic assignments. While for 16S rDNA, relevant regions have been well described, no truly systematic design of 18S rDNA primers aimed at resolving eukaryotic diversity has yet been reported. Here we used 31,862 18S rDNA sequences to design a set of broad-taxonomic range degenerate PCR primers. We simulated the phylogenetic information that each candidate primer pair would retrieve using paired-or single-end reads of various lengths, representing different sequencing technologies. Primer pairs targeting the V4 region performed best, allowing discrimination with paired-end reads as short as 150 bp (with 75% accuracy at genus level). The conditions for PCR amplification were optimised for one of these primer pairs and this was used to amplify 18S rDNA sequences from isolates as well as from a range of environmental samples which were then Illumina sequenced and analysed, revealing good concordance between expected and observed results. In summary, the reported primer sets will allow minimally biased assessment of eukaryotic diversity in different microbial ecosystems.

  • 9.
    Hugerth, Luisa W.
    et al.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Wefer, Hugo A.
    Lundin, Sverker
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Jakobsson, Hedvig E.
    Lindberg, Mathilda
    Rodin, Sandra
    Engstrand, Lars
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    DegePrime, a Program for Degenerate Primer Design for Broad-Taxonomic-Range PCR in Microbial Ecology Studies2014Inngår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 80, nr 16, s. 5116-5123Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The taxonomic composition of a microbial community can be deduced by analyzing its rRNA gene content by, e. g., high-throughput DNA sequencing or DNA chips. Such methods typically are based on PCR amplification of rRNA gene sequences using broad-taxonomic-range PCR primers. In these analyses, the use of optimal primers is crucial for achieving an unbiased representation of community composition. Here, we present the computer program DegePrime that, for each position of a multiple sequence alignment, finds a degenerate oligomer of as high coverage as possible and outputs its coverage among taxonomic divisions. We show that our novel heuristic, which we call weighted randomized combination, performs better than previously described algorithms for solving the maximum coverage degenerate primer design problem. We previously used DegePrime to design a broad-taxonomic-range primer pair that targets the bacterial V3-V4 region (341F-805R) (D. P. Herlemann, M. Labrenz, K. Jurgens, S. Bertilsson, J. J. Waniek, and A. F. Andersson, ISME J. 5:1571-1579, 2011, http://dx.doi.org/10.1038/ismej.2011.41), and here we use the program to significantly increase the coverage of a primer pair (515F-806R) widely used for Illumina-based surveys of bacterial and archaeal diversity. By comparison with shotgun metagenomics, we show that the primers give an accurate representation of microbial diversity in natural samples.

  • 10. Lindh, Markus V.
    et al.
    Sjostedt, Johanna
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Baltar, Federico
    Hugerth, Luisa W.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lundin, Daniel
    Muthusamy, Saraladevi
    Legrand, Catherine
    Pinhassi, Jarone
    Disentangling seasonal bacterioplankton population dynamics by high-frequency sampling2015Inngår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 17, nr 7, s. 2459-2476Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Multiyear comparisons of bacterioplankton succession reveal that environmental conditions drive community shifts with repeatable patterns between years. However, corresponding insight into bacterioplankton dynamics at a temporal resolution relevant for detailed examination of variation and characteristics of specific populations within years is essentially lacking. During 1 year, we collected 46 samples in the Baltic Sea for assessing bacterial community composition by 16S rRNA gene pyrosequencing (nearly twice weekly during productive season). Beta-diversity analysis showed distinct clustering of samples, attributable to seemingly synchronous temporal transitions among populations (populations defined by 97% 16S rRNA gene sequence identity). A wide spectrum of bacterioplankton dynamics was evident, where divergent temporal patterns resulted both from pronounced differences in relative abundance and presence/absence of populations. Rates of change in relative abundance calculated for individual populations ranged from 0.23 to 1.79 day(-1). Populations that were persistently dominant, transiently abundant or generally rare were found in several major bacterial groups, implying evolution has favoured a similar variety of life strategies within these groups. These findings suggest that high temporal resolution sampling allows constraining the timescales and frequencies at which distinct populations transition between being abundant or rare, thus potentially providing clues about physical, chemical or biological forcing on bacterioplankton community structure.

  • 11. Lindh, Markus V.
    et al.
    Sjostedt, Johanna
    Ekstam, Borje
    Casini, Michele
    Lundin, Daniel
    Hugerth, Luisa W.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för bioteknologi (BIO).
    Hu, Yue O. O.
    KTH, Skolan för bioteknologi (BIO). KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO). KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Andersson, Agneta
    Legrand, Catherine
    Pinhassi, Jarone
    Metapopulation theory identifies biogeographical patterns among core and satellite marine bacteria scaling from tens to thousands of kilometers2017Inngår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 19, nr 3, s. 1222-1236Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metapopulation theory developed in terrestrial ecology provides applicable frameworks for interpreting the role of local and regional processes in shaping species distribution patterns. Yet, empirical testing of metapopulation models on microbial communities is essentially lacking. We determined regional bacterioplankton dynamics from monthly transect sampling in the Baltic Sea Proper using 16S rRNA gene sequencing. A strong positive trend was found between local relative abundance and occupancy of populations. Notably, the occupancy-frequency distributions were significantly bimodal with a satellite mode of rare endemic populations and a core mode of abundant cosmopolitan populations (e.g. Synechococcus, SAR11 and SAR86 clade members). Temporal changes in population distributions supported several theoretical frameworks. Still, bimodality was found among bacterioplankton communities across the entire Baltic Sea, and was also frequent in globally distributed datasets. Datasets spanning waters with widely different physicochemical characteristics or environmental gradients typically lacked significant bimodal patterns. When such datasets were divided into subsets with coherent environmental conditions, bimodal patterns emerged, highlighting the importance of positive feedbacks between local abundance and occupancy within specific biomes. Thus, metapopulation theory applied to microbial biogeography can provide novel insights into the mechanisms governing shifts in biodiversity resulting from natural or anthropogenically induced changes in the environment.

  • 12. Wampach, Linda
    et al.
    Heintz-Buschart, Anna
    Hogan, Angela
    Muller, Emilie E. L.
    Narayanasamy, Shaman
    Laczny, Cedric C.
    Hugerth, Luisa
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Bindl, Lutz
    Bottu, Jean
    Andersson, Anders F.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    de Beaufort, Carine
    Wilmes, Paul
    Colonization and Succession within the Human Gut Microbiome by Archaea, Bacteria, and Microeukaryotes during the First Year of Life2017Inngår i: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 8, artikkel-id 738Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Perturbations to the colonization process of the human gastrointestinal tract have been suggested to result in adverse health effects later in life. Although much research has been performed on bacterial colonization and succession, much less is known about the other two domains of life, archaea, and eukaryotes. Here we describe colonization and succession by bacteria, archaea and microeukaryotes during the first year of life (samples collected around days 1, 3, 5, 28, 150, and 365) within the gastrointestinal tract of infants delivered either vaginally or by cesarean section and using a combination of quantitative real-time PCR as well as 16S and 18S rRNA gene amplicon sequencing. Sequences from organisms belonging to all three domains of life were detectable in all of the collected meconium samples. The microeukaryotic community composition fluctuated strongly over time and early diversification was delayed in infants receiving formula milk. Cesarean section-delivered (CSD) infants experienced a delay in colonization and succession, which was observed for all three domains of life. Shifts in prokaryotic succession in CSD infants compared to vaginally delivered (VD) infants were apparent as early as days 3 and 5, which were characterized by increased relative abundances of the genera Streptococcus and Staphylococcus, and a decrease in relative abundance for the genera Bifidobacterium and Bacteroides. Generally, a depletion in Bacteroidetes was detected as early as day 5 postpartum in CSD infants, causing a significantly increased Firmicutes/Bacteroidetes ratio between days 5 and 150 when compared to VD infants. Although the delivery mode appeared to have the strongest influence on differences between the infants, other factors such as a younger gestational age or maternal antibiotics intake likely contributed to the observed patterns as well. Our findings complement previous observations of a delay in colonization and succession of CSD infants, which affects not only bacteria but also archaea and microeukaryotes. This further highlights the need for resolving bacterial, archaeal, and microeukaryotic dynamics in future longitudinal studies of microbial colonization and succession within the neonatal gastrointestinal tract.

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