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Stroeva AR, Klyukina AA, Vidishcheva ON, Poludetkina EN, Solovyeva MA, Pyrkin VO, Gavirova LA, Birkeland NK, Akhmanov GG, Bonch-Osmolovskaya EA, Merkel AY. Structure of Benthic Microbial Communities in the Northeastern Part of the Barents Sea. Microorganisms 2024; 12:387. [PMID: 38399791 PMCID: PMC10892650 DOI: 10.3390/microorganisms12020387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
The Barents Sea shelf is one of the most economically promising regions in the Arctic in terms of its resources and geographic location. However, benthic microbial communities of the northeastern Barents Sea are still barely studied. Here, we present a detailed systematic description of the structures of microbial communities located in the sediments and bottom water of the northeastern Barents Sea based on 16S rRNA profiling and a qPCR assessment of the total prokaryotic abundance in 177 samples. Beta- and alpha-diversity analyses revealed a clear difference between the microbial communities of diverse sediment layers and bottom-water fractions. We identified 101 microbial taxa whose representatives had statistically reliable distribution patterns between these ecotopes. Analysis of the correlation between microbial community structure and geological data yielded a number of important results-correlations were found between the abundance of individual microbial taxa and bottom relief, thickness of marine sediments, presence of hydrotrolite interlayers, and the values of pH and Eh. We also demonstrated that a relatively high abundance of prokaryotes in sediments can be caused by the proliferation of Deltaproteobacteria representatives, in particular, sulfate and iron reducers.
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Affiliation(s)
| | - Alexandra A. Klyukina
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | | | | | | | | | | | - Nils-Kåre Birkeland
- Department of Biological Sciences, University of Bergen, P.O. Box 7803, NO-5020 Bergen, Norway
| | | | - Elizaveta A. Bonch-Osmolovskaya
- Lomonosov Moscow State University, 119234 Moscow, Russia
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Alexander Y. Merkel
- Lomonosov Moscow State University, 119234 Moscow, Russia
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
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2
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Ghaly TM, Focardi A, Elbourne LDH, Sutcliffe B, Humphreys W, Paulsen IT, Tetu SG. Stratified microbial communities in Australia's only anchialine cave are taxonomically novel and drive chemotrophic energy production via coupled nitrogen-sulphur cycling. MICROBIOME 2023; 11:190. [PMID: 37626351 PMCID: PMC10463829 DOI: 10.1186/s40168-023-01633-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 07/27/2023] [Indexed: 08/27/2023]
Abstract
BACKGROUND Anchialine environments, in which oceanic water mixes with freshwater in coastal aquifers, are characterised by stratified water columns with complex physicochemical profiles. These environments, also known as subterranean estuaries, support an abundance of endemic macro and microorganisms. There is now growing interest in characterising the metabolisms of anchialine microbial communities, which is essential for understanding how complex ecosystems are supported in extreme environments, and assessing their vulnerability to environmental change. However, the diversity of metabolic strategies that are utilised in anchialine ecosystems remains poorly understood. RESULTS Here, we employ shotgun metagenomics to elucidate the key microorganisms and their dominant metabolisms along a physicochemical profile in Bundera Sinkhole, the only known continental subterranean estuary in the Southern Hemisphere. Genome-resolved metagenomics suggests that the communities are largely represented by novel taxonomic lineages, with 75% of metagenome-assembled genomes assigned to entirely new or uncharacterised families. These diverse and novel taxa displayed depth-dependent metabolisms, reflecting distinct phases along dissolved oxygen and salinity gradients. In particular, the communities appear to drive nutrient feedback loops involving nitrification, nitrate ammonification, and sulphate cycling. Genomic analysis of the most highly abundant members in this system suggests that an important source of chemotrophic energy is generated via the metabolic coupling of nitrogen and sulphur cycling. CONCLUSION These findings substantially contribute to our understanding of the novel and specialised microbial communities in anchialine ecosystems, and highlight key chemosynthetic pathways that appear to be important in these energy-limited environments. Such knowledge is essential for the conservation of anchialine ecosystems, and sheds light on adaptive processes in extreme environments. Video Abstract.
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Affiliation(s)
- Timothy M Ghaly
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - Amaranta Focardi
- Climate Change Cluster (C3), University of Technology Sydney, Sydney, Australia
| | - Liam D H Elbourne
- School of Natural Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | | | - William Humphreys
- School of Biological Sciences, University of Western Australia, Perth, Australia
| | - Ian T Paulsen
- School of Natural Sciences, Macquarie University, Sydney, Australia.
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia.
| | - Sasha G Tetu
- School of Natural Sciences, Macquarie University, Sydney, Australia.
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia.
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3
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Li J, Törkel K, Koch J, Tanabe TS, Hsu HY, Dahl C. In the Alphaproteobacterium Hyphomicrobium denitrificans SoxR Serves a Sulfane Sulfur-Responsive Repressor of Sulfur Oxidation. Antioxidants (Basel) 2023; 12:1620. [PMID: 37627615 PMCID: PMC10451225 DOI: 10.3390/antiox12081620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023] Open
Abstract
In organisms that use reduced sulfur compounds as alternative or additional electron donors to organic compounds, transcriptional regulation of genes for enzymes involved in sulfur oxidation is needed to adjust metabolic flux to environmental conditions. However, little is known about the sensing and response to inorganic sulfur compounds such as thiosulfate in sulfur-oxidizing bacteria. In the Alphaproteobacterium Hyphomicrobium denitrificans, one strategy is the use of the ArsR-SmtB-type transcriptional regulator SoxR. We show that this homodimeric repressor senses sulfane sulfur and that it is crucial for the expression not only of sox genes encoding the components of a truncated periplasmic thiosulfate-oxidizing enzyme system but also of several other sets of genes for enzymes of sulfur oxidation. DNA binding and transcriptional regulatory activity of SoxR are controlled by polysulfide-dependent cysteine modification. The repressor uses the formation of a sulfur bridge between two conserved cysteines as a trigger to bind and release DNA and can also form a vicinal disulfide bond to orchestrate a response to oxidizing conditions. The importance of the sulfur bridge forming cysteines was confirmed by site-directed mutagenesis, mass spectrometry, and gel shift assays. In vivo, SoxR interacts directly or indirectly with a second closely related repressor, sHdrR.
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Affiliation(s)
| | | | | | | | | | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, 53115 Bonn, Germany; (J.L.); (K.T.); (J.K.); (T.S.T.); (H.Y.H.)
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4
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Barosa B, Ferrillo A, Selci M, Giardina M, Bastianoni A, Correggia M, di Iorio L, Bernardi G, Cascone M, Capuozzo R, Intoccia M, Price R, Vetriani C, Cordone A, Giovannelli D. Mapping the microbial diversity associated with different geochemical regimes in the shallow-water hydrothermal vents of the Aeolian archipelago, Italy. Front Microbiol 2023; 14:1134114. [PMID: 37637107 PMCID: PMC10452888 DOI: 10.3389/fmicb.2023.1134114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 07/25/2023] [Indexed: 08/29/2023] Open
Abstract
Shallow-water hydrothermal vents are unique marine environments ubiquitous along the coast of volcanically active regions of the planet. In contrast to their deep-sea counterparts, primary production at shallow-water vents relies on both photoautotrophy and chemoautotrophy. Such processes are supported by a range of geochemical regimes driven by different geological settings. The Aeolian archipelago, located in the southern Tyrrhenian sea, is characterized by intense hydrothermal activity and harbors some of the best sampled shallow-water vents of the Mediterranean Sea. Despite this, the correlation between microbial diversity, geochemical regimes and geological settings of the different volcanic islands of the archipelago is largely unknown. Here, we report the microbial diversity associated with six distinct shallow-water hydrothermal vents of the Aeolian Islands using a combination of 16S rRNA amplicon sequencing along with physicochemical and geochemical measurements. Samples were collected from biofilms, fluids and sediments from shallow vents on the islands of Lipari, Panarea, Salina, and Vulcano. Two new shallow vent locations are described here for the first time. Our results show the presence of diverse microbial communities consistent in their composition with the local geochemical regimes. The shallow water vents of the Aeolian Islands harbor highly diverse microbial community and should be included in future conservation efforts.
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Affiliation(s)
- Bernardo Barosa
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | | | - Matteo Selci
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | - Marco Giardina
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | - Alessia Bastianoni
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | - Monica Correggia
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | - Luciano di Iorio
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | | | - Martina Cascone
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | - Rosaria Capuozzo
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | - Michele Intoccia
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | - Roy Price
- School of Marine and Atmospheric Sciences, Stony Brook, NY, United States
| | - Costantino Vetriani
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, United States
- Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, United States
| | - Angelina Cordone
- Department of Biology, University of Naples “Federico II”, Naples, Italy
| | - Donato Giovannelli
- Department of Biology, University of Naples “Federico II”, Naples, Italy
- Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, United States
- Istituto per le Risorse Biologiche e Biotecnologiche Marine, Consiglio Nazionale Delle Ricerche, CNR-IRBIM, Ancona, Italy
- Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Tokyo, Japan
- Marine Chemistry and Geochemistry Department–Woods Hole Oceanographic Institution, Woods Hole, MA, United States
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5
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Schultz J, Modolon F, Peixoto RS, Rosado AS. Shedding light on the composition of extreme microbial dark matter: alternative approaches for culturing extremophiles. Front Microbiol 2023; 14:1167718. [PMID: 37333658 PMCID: PMC10272570 DOI: 10.3389/fmicb.2023.1167718] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/09/2023] [Indexed: 06/20/2023] Open
Abstract
More than 20,000 species of prokaryotes (less than 1% of the estimated number of Earth's microbial species) have been described thus far. However, the vast majority of microbes that inhabit extreme environments remain uncultured and this group is termed "microbial dark matter." Little is known regarding the ecological functions and biotechnological potential of these underexplored extremophiles, thus representing a vast untapped and uncharacterized biological resource. Advances in microbial cultivation approaches are key for a detailed and comprehensive characterization of the roles of these microbes in shaping the environment and, ultimately, for their biotechnological exploitation, such as for extremophile-derived bioproducts (extremozymes, secondary metabolites, CRISPR Cas systems, and pigments, among others), astrobiology, and space exploration. Additional efforts to enhance culturable diversity are required due to the challenges imposed by extreme culturing and plating conditions. In this review, we summarize methods and technologies used to recover the microbial diversity of extreme environments, while discussing the advantages and disadvantages associated with each of these approaches. Additionally, this review describes alternative culturing strategies to retrieve novel taxa with their unknown genes, metabolisms, and ecological roles, with the ultimate goal of increasing the yields of more efficient bio-based products. This review thus summarizes the strategies used to unveil the hidden diversity of the microbiome of extreme environments and discusses the directions for future studies of microbial dark matter and its potential applications in biotechnology and astrobiology.
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Affiliation(s)
- Júnia Schultz
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Flúvio Modolon
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raquel Silva Peixoto
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Alexandre Soares Rosado
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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Impact of high Fe-concentrations on microbial community structure and dissolved organics in hydrothermal plumes: an experimental study. Sci Rep 2022; 12:20723. [PMID: 36456707 PMCID: PMC9715565 DOI: 10.1038/s41598-022-25320-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/28/2022] [Indexed: 12/05/2022] Open
Abstract
Iron (Fe) is an essential trace element for life. In the ocean, Fe can be exceptionally scarce and thus biolimiting or extremely enriched causing microbial stress. The ability of hydrothermal plume microbes to counteract unfavorable Fe-concentrations up to 10 mM is investigated through experiments. While Campylobacterota (Sulfurimonas) are prominent in a diverse community at low to intermediate Fe-concentrations, the highest 10 mM Fe-level is phylogenetically less diverse and dominated by the SUP05 clade (Gammaproteobacteria), a species known to be genetically well equipped to strive in high-Fe environments. In all incubations, Fe-binding ligands were produced in excess of the corresponding Fe-concentration level, possibly facilitating biological Fe-uptake in low-Fe incubations and detoxification in high-Fe incubations. The diversity of Fe-containing formulae among dissolved organics (SPE-DOM) decreased with increasing Fe-concentration, which may reflect toxic conditions of the high-Fe treatments. A DOM-derived degradation index (IDEG) points to a degradation magnitude (microbial activity) that decreases with Fe and/or selective Fe-DOM coagulation. Our results show that some hydrothermal microbes (especially Gammaproteobacteria) have the capacity to thrive even at unfavorably high Fe-concentrations. These ligand-producing microbes could hence play a key role in keeping Fe in solution, particularly in environments, where Fe precipitation dominates and toxic conditions prevail.
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7
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Dede B, Hansen CT, Neuholz R, Schnetger B, Kleint C, Walker S, Bach W, Amann R, Meyerdierks A. Niche differentiation of sulfur-oxidizing bacteria (SUP05) in submarine hydrothermal plumes. THE ISME JOURNAL 2022; 16:1479-1490. [PMID: 35082431 PMCID: PMC9123188 DOI: 10.1038/s41396-022-01195-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 01/03/2022] [Accepted: 01/10/2022] [Indexed: 11/09/2022]
Abstract
Hydrothermal plumes transport reduced chemical species and metals into the open ocean. Despite their considerable spatial scale and impact on biogeochemical cycles, niche differentiation of abundant microbial clades is poorly understood. Here, we analyzed the microbial ecology of two bathy- (Brothers volcano; BrV-cone and northwest caldera; NWC) and a mesopelagic (Macauley volcano; McV) plumes on the Kermadec intra-oceanic arc in the South Pacific Ocean. The microbial community structure, determined by a combination of 16S rRNA gene, fluorescence in situ hybridization and metagenome analysis, was similar to the communities observed in other sulfur-rich plumes. This includes a dominance of the vent characteristic SUP05 clade (up to 22% in McV and 51% in BrV). In each of the three plumes analyzed, the community was dominated by a different yet uncultivated chemoautotrophic SUP05 species, here, provisionally named, Candidatus Thioglobus vadi (McV), Candidatus Thioglobus vulcanius (BrV-cone) and Candidatus Thioglobus plumae (BrV-NWC). Statistical analyses, genomic potential and mRNA expression profiles suggested a SUP05 niche partitioning based on sulfide and iron concentration as well as water depth. A fourth SUP05 species was present at low frequency throughout investigated plume samples and may be capable of heterotrophic or mixotrophic growth. Taken together, we propose that small variations in environmental parameters and depth drive SUP05 niche partitioning in hydrothermal plumes.
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Affiliation(s)
- Bledina Dede
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Christian T Hansen
- MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Rene Neuholz
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Group: Quality Assurance and Cyber-Physical Systems, Bremen, Germany
| | - Bernhard Schnetger
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Charlotte Kleint
- MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- Department of Physics and Earth Sciences, Jacobs University Bremen, Bremen, Germany
| | - Sharon Walker
- National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, WA, USA
| | - Wolfgang Bach
- MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- Geoscience Department, University of Bremen, Bremen, Germany
| | - Rudolf Amann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
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8
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Abstract
The SUP05 clade of gammaproteobacteria (Thioglobaceae) comprises both primary producers and primary consumers of organic carbon in the oceans. Host-associated autotrophs are a principal source of carbon and other nutrients for deep-sea eukaryotes at hydrothermal vents, and their free-living relatives are a primary source of organic matter in seawater at vents and in marine oxygen minimum zones. Similar to other abundant marine heterotrophs, such as SAR11 and Roseobacter, heterotrophic Thioglobaceae use the dilute pool of osmolytes produced by phytoplankton for growth, including methylated amines and sulfonates. Heterotrophic members are common throughout the ocean, and autotrophic members are abundant at hydrothermal vents and in anoxic waters; combined, they can account for more than 50% of the total bacterial community. Studies of both cultured and uncultured representatives from this diverse family are providing novel insights into the shifting biogeochemical roles of autotrophic and heterotrophic bacteria that cross oxic-anoxic boundary layers in the ocean.
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Affiliation(s)
- Robert M Morris
- School of Oceanography, University of Washington, Seattle, Washington 98195, USA;
| | - Rachel L Spietz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana 59717, USA;
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9
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De Corte D, Muck S, Tiroch J, Mena C, Herndl GJ, Sintes E. Microbes mediating the sulfur cycle in the Atlantic Ocean and their link to chemolithoautotrophy. Environ Microbiol 2021; 23:7152-7167. [PMID: 34490972 DOI: 10.1111/1462-2920.15759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 08/18/2021] [Accepted: 09/03/2021] [Indexed: 11/26/2022]
Abstract
Only about 10%-30% of the organic matter produced in the epipelagic layers reaches the dark ocean. Under these limiting conditions, reduced inorganic substrates might be used as an energy source to fuel prokaryotic chemoautotrophic and/or mixotrophic activity. The aprA gene encodes the alpha subunit of the adenosine-5'-phosphosulfate (APS) reductase, present in sulfate-reducing (SRP) and sulfur-oxidizing prokaryotes (SOP). The sulfur-oxidizing pathway can be coupled to inorganic carbon fixation via the Calvin-Benson-Bassham cycle. The abundances of aprA and cbbM, encoding RuBisCO form II (the key CO2 fixing enzyme), were determined over the entire water column along a latitudinal transect in the Atlantic from 64°N to 50°S covering six oceanic provinces. The abundance of aprA and cbbM genes significantly increased with depth reaching the highest abundances in meso- and upper bathypelagic layers. The contribution of cells containing these genes also increased from mesotrophic towards oligotrophic provinces, suggesting that under nutrient limiting conditions alternative energy sources are advantageous. However, the aprA/cbbM ratios indicated that only a fraction of the SOP is associated with inorganic carbon fixation. The aprA harbouring prokaryotic community was dominated by Pelagibacterales in surface and mesopelagic waters, while Candidatus Thioglobus, Chromatiales and the Deltaproteobacterium_SCGC dominated the bathypelagic realm. Noticeably, the contribution of the SRP to the prokaryotic community harbouring aprA gene was low, suggesting a major utilization of inorganic sulfur compounds either as an energy source (occasionally coupled with inorganic carbon fixation) or in biosynthesis pathways.
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Affiliation(s)
- Daniele De Corte
- Institute for Chemistry and Biology of the Marine Environment, Carl Von Ossietzky University, Oldenburg, Germany
| | - Simone Muck
- Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Johanna Tiroch
- Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Catalina Mena
- Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Palma, Spain
| | - Gerhard J Herndl
- Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
- NIOZ, Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Utrecht University, Den Burg, The Netherlands
| | - Eva Sintes
- Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
- Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Palma, Spain
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10
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Kim S, Islam MR, Kang I, Cho JC. Cultivation of Dominant Freshwater Bacterioplankton Lineages Using a High-Throughput Dilution-to-Extinction Culturing Approach Over a 1-Year Period. Front Microbiol 2021; 12:700637. [PMID: 34385989 PMCID: PMC8353197 DOI: 10.3389/fmicb.2021.700637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/09/2021] [Indexed: 11/13/2022] Open
Abstract
Although many culture-independent molecular analyses have elucidated a great diversity of freshwater bacterioplankton, the ecophysiological characteristics of several abundant freshwater bacterial groups are largely unknown due to the scarcity of cultured representatives. Therefore, a high-throughput dilution-to-extinction culturing (HTC) approach was implemented herein to enable the culture of these bacterioplankton lineages using water samples collected at various seasons and depths from Lake Soyang, an oligotrophic reservoir located in South Korea. Some predominant freshwater bacteria have been isolated from Lake Soyang via HTC (e.g., the acI lineage); however, large-scale HTC studies encompassing different seasons and water depths have not been documented yet. In this HTC approach, bacterial growth was detected in 14% of 5,376 inoculated wells. Further, phylogenetic analyses of 16S rRNA genes from a total of 605 putatively axenic bacterial cultures indicated that the HTC isolates were largely composed of Actinobacteria, Bacteroidetes, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Verrucomicrobia. Importantly, the isolates were distributed across diverse taxa including phylogenetic lineages that are widely known cosmopolitan and representative freshwater bacterial groups such as the acI, acIV, LD28, FukuN57, MNG9, and TRA3-20 lineages. However, some abundant bacterial groups including the LD12 lineage, Chloroflexi, and Acidobacteria could not be domesticated. Among the 71 taxonomic groups in the HTC isolates, representative strains of 47 groups could either form colonies on agar plates or be revived from frozen glycerol stocks. Additionally, season and water depth significantly affected bacterial community structure, as demonstrated by 16S rRNA gene amplicon sequencing analyses. Therefore, our study successfully implemented a dilution-to-extinction cultivation strategy to cultivate previously uncultured or underrepresented freshwater bacterial groups, thus expanding the basis for future multi-omic studies.
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Affiliation(s)
- Suhyun Kim
- Department of Biological Sciences and Bioengineering, Inha University, Incheon, South Korea
| | - Md Rashedul Islam
- Bacteriophage Biology Laboratory, Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, ON, Canada
| | - Ilnam Kang
- Department of Biological Sciences, Center for Molecular and Cell Biology, Inha University, Incheon, South Korea
| | - Jang-Cheon Cho
- Department of Biological Sciences and Bioengineering, Inha University, Incheon, South Korea
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van Vliet DM, von Meijenfeldt FB, Dutilh BE, Villanueva L, Sinninghe Damsté JS, Stams AJ, Sánchez‐Andrea I. The bacterial sulfur cycle in expanding dysoxic and euxinic marine waters. Environ Microbiol 2021; 23:2834-2857. [PMID: 33000514 PMCID: PMC8359478 DOI: 10.1111/1462-2920.15265] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 09/03/2020] [Accepted: 09/28/2020] [Indexed: 01/29/2023]
Abstract
Dysoxic marine waters (DMW, < 1 μM oxygen) are currently expanding in volume in the oceans, which has biogeochemical, ecological and societal consequences on a global scale. In these environments, distinct bacteria drive an active sulfur cycle, which has only recently been recognized for open-ocean DMW. This review summarizes the current knowledge on these sulfur-cycling bacteria. Critical bottlenecks and questions for future research are specifically addressed. Sulfate-reducing bacteria (SRB) are core members of DMW. However, their roles are not entirely clear, and they remain largely uncultured. We found support for their remarkable diversity and taxonomic novelty by mining metagenome-assembled genomes from the Black Sea as model ecosystem. We highlight recent insights into the metabolism of key sulfur-oxidizing SUP05 and Sulfurimonas bacteria, and discuss the probable involvement of uncultivated SAR324 and BS-GSO2 bacteria in sulfur oxidation. Uncultivated Marinimicrobia bacteria with a presumed organoheterotrophic metabolism are abundant in DMW. Like SRB, they may use specific molybdoenzymes to conserve energy from the oxidation, reduction or disproportionation of sulfur cycle intermediates such as S0 and thiosulfate, produced from the oxidation of sulfide. We expect that tailored sampling methods and a renewed focus on cultivation will yield deeper insight into sulfur-cycling bacteria in DMW.
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Affiliation(s)
- Daan M. van Vliet
- Laboratory of MicrobiologyWageningen University and Research, Stippeneng 4, 6708WEWageningenNetherlands
| | | | - Bas E. Dutilh
- Theoretical Biology and Bioinformatics, Science for LifeUtrecht University, Padualaan 8, 3584 CHUtrechtNetherlands
| | - Laura Villanueva
- Department of Marine Microbiology and BiogeochemistryRoyal Netherlands Institute for Sea Research (NIOZ), Utrecht University, Landsdiep 4, 1797 SZ, 'tHorntje (Texel)Netherlands
| | - Jaap S. Sinninghe Damsté
- Department of Marine Microbiology and BiogeochemistryRoyal Netherlands Institute for Sea Research (NIOZ), Utrecht University, Landsdiep 4, 1797 SZ, 'tHorntje (Texel)Netherlands
- Department of Earth Sciences, Faculty of GeosciencesUtrecht University, Princetonlaan 8A, 3584 CBUtrechtNetherlands
| | - Alfons J.M. Stams
- Laboratory of MicrobiologyWageningen University and Research, Stippeneng 4, 6708WEWageningenNetherlands
- Centre of Biological EngineeringUniversity of Minho, Campus de Gualtar, 4710‐057BragaPortugal
| | - Irene Sánchez‐Andrea
- Laboratory of MicrobiologyWageningen University and Research, Stippeneng 4, 6708WEWageningenNetherlands
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Artificial neural network analysis of microbial diversity in the central and southern Adriatic Sea. Sci Rep 2021; 11:11186. [PMID: 34045659 PMCID: PMC8159981 DOI: 10.1038/s41598-021-90863-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 05/17/2021] [Indexed: 11/29/2022] Open
Abstract
Bacteria are an active and diverse component of pelagic communities. The identification of main factors governing microbial diversity and spatial distribution requires advanced mathematical analyses. Here, the bacterial community composition was analysed, along with a depth profile, in the open Adriatic Sea using amplicon sequencing of bacterial 16S rRNA and the Neural gas algorithm. The performed analysis classified the sample into four best matching units representing heterogenic patterns of the bacterial community composition. The observed parameters were more differentiated by depth than by area, with temperature and identified salinity as important environmental variables. The highest diversity was observed at the deep chlorophyll maximum, while bacterial abundance and production peaked in the upper layers. The most of the identified genera belonged to Proteobacteria, with uncultured AEGEAN-169 and SAR116 lineages being dominant Alphaproteobacteria, and OM60 (NOR5) and SAR86 being dominant Gammaproteobacteria. Marine Synechococcus and Cyanobium-related species were predominant in the shallow layer, while Prochlorococcus MIT 9313 formed a higher portion below 50 m depth. Bacteroidota were represented mostly by uncultured lineages (NS4, NS5 and NS9 marine lineages). In contrast, Actinobacteriota were dominated by a candidatus genus Ca. Actinomarina. A large contribution of Nitrospinae was evident at the deepest investigated layer. Our results document that neural network analysis of environmental data may provide a novel insight into factors affecting picoplankton in the open sea environment.
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Kim S, Park MS, Song J, Kang I, Cho JC. High-throughput cultivation based on dilution-to-extinction with catalase supplementation and a case study of cultivating acI bacteria from Lake Soyang. J Microbiol 2020; 58:893-905. [PMID: 33125668 DOI: 10.1007/s12275-020-0452-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022]
Abstract
Multi-omics approaches, including metagenomics and single-cell amplified genomics, have revolutionized our understanding of the hidden diversity and function of microbes in nature. Even in the omics age, cultivation is an essential discipline in microbial ecology since microbial cultures are necessary to assess the validity of an in silico prediction about the microbial metabolism and to isolate viruses infecting bacteria and archaea. However, the ecophysiological characteristics of predominant freshwater bacterial lineages remain largely unknown due to the scarcity of cultured representatives. In an ongoing effort to cultivate the uncultured majority of freshwater bacteria, the most abundant freshwater Actinobacteria acI clade has recently been cultivated from Lake Soyang through catalase-supplemented high-throughput cultivation based on dilution-to-extinction. This method involves physical isolation of target microbes from mixed populations, culture media simulating natural habitats, and removal of toxic compounds. In this protocol, we describe detailed procedures for isolating freshwater oligotrophic microbes, as well as the essence of the dilution-to-extinction culturing. As a case study employing the catalase-supplemented dilution-to-extinction protocol, we also report a cultivation trial using a water sample collected from Lake Soyang. Of the 480 cultivation wells inoculated with a single lake-water sample, 75 new acI strains belonging to 8 acI tribes (acI-A1, A2, A4, A5, A6, A7, B1, B4, C1, and C2) were cultivated, and each representative strain per subclade could be revived from glycerol stocks. These cultivation results demonstrate that the protocol described in this study is efficient in isolating freshwater bacterioplankton harboring streamlined genomes.
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Affiliation(s)
- Suhyun Kim
- Department of Biological Sciences, Inha University, Incheon, 22212, Republic of Korea
| | - Miri S Park
- Department of Biological Sciences, Inha University, Incheon, 22212, Republic of Korea
| | - Jaeho Song
- Department of Biological Sciences, Inha University, Incheon, 22212, Republic of Korea
| | - Ilnam Kang
- Department of Biological Sciences, Inha University, Incheon, 22212, Republic of Korea
| | - Jang-Cheon Cho
- Department of Biological Sciences, Inha University, Incheon, 22212, Republic of Korea.
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Gifford SM, Zhao L, Stemple B, DeLong K, Medeiros PM, Seim H, Marchetti A. Microbial Niche Diversification in the Galápagos Archipelago and Its Response to El Niño. Front Microbiol 2020; 11:575194. [PMID: 33193187 PMCID: PMC7644778 DOI: 10.3389/fmicb.2020.575194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/30/2020] [Indexed: 11/24/2022] Open
Abstract
The Galápagos Archipelago is located at the intersection of several major oceanographic features that produce diverse environmental conditions around the islands, and thus has the potential to serve as a natural laboratory for discerning the underlying environmental factors that structure marine microbial communities. Here we used quantitative metagenomics to characterize microbial communities in relation to archipelago marine habitats, and how those populations shift due to substantial environmental changes brought on by El Niño. Environmental conditions such as temperature, salinity, inorganic dissolved nutrients, and dissolved organic carbon (DOC) concentrations varied throughout the archipelago, revealing a diversity of potential microbial niches arising from upwelling, oligotrophic to eutrophic gradients, physical isolation, and potential island mass effects. The volumetric abundances of microbial community members shifted with these environmental changes and revealed several taxonomic indicators of different water masses. This included a transition from a Synechococcus dominated system in the west to an even mix of Synechococcus and Prochlorococcus in the east, mirroring the archipelago’s mesotrophic to oligotrophic and productivity gradients. Several flavobacteria groups displayed characteristic habitat distributions, including enrichment of Polaribacter and Tenacibaculum clades in the relatively nutrient rich western waters, Leeuwenhoekiella spp. that were enriched in the more nutrient-deplete central and eastern sites, and the streamlined MS024-2A group found to be abundant across all sites. During the 2015/16 El Niño event, both environmental conditions and microbial community composition were substantially altered, primarily on the western side of the archipelago due to the reduction of upwelling from the Equatorial Undercurrent. When the upwelling resumed, concentrations of inorganic nutrients and DOC at the western surface sites were more typical of mesopelagic depths. Correspondingly, Synechococcus abundances decreased by an order of magnitude, while groups associated with deeper water masses were enriched, including streamlined roseobacters HTCC2255 and HIMB11, Thioglobacaceae, methylotrophs (Methylophilaceae), archaea (Nitrosopumilaceae), and distinct subpopulations of Pelagibaceriales (SAR11 clade). These results provide a quantitative framework to connect community-wide microbial volumetric abundances to their environmental drivers, and thus incorporation into biogeochemical and ecological models.
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Affiliation(s)
- Scott M Gifford
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Liang Zhao
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Brooke Stemple
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Kimberly DeLong
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Patricia M Medeiros
- Department of Marine Sciences, University of Georgia, Athens, GA, United States
| | - Harvey Seim
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Adrian Marchetti
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Expanding the Diversity of Bacterioplankton Isolates and Modeling Isolation Efficacy with Large-Scale Dilution-to-Extinction Cultivation. Appl Environ Microbiol 2020; 86:AEM.00943-20. [PMID: 32561583 PMCID: PMC7440811 DOI: 10.1128/aem.00943-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/13/2020] [Indexed: 12/13/2022] Open
Abstract
Even before the coining of the term “great plate count anomaly” in the 1980s, scientists had noted the discrepancy between the number of microorganisms observed under the microscope and the number of colonies that grew on traditional agar media. New cultivation approaches have reduced this disparity, resulting in the isolation of some of the “most wanted” bacterial lineages. Nevertheless, the vast majority of microorganisms remain uncultured, hampering progress toward answering fundamental biological questions about many important microorganisms. Furthermore, few studies have evaluated the underlying factors influencing cultivation success, limiting our ability to improve cultivation efficacy. Our work details the use of dilution-to-extinction (DTE) cultivation to expand the phylogenetic and geographic diversity of available axenic cultures. We also provide a new model of the DTE approach that uses cultivation results and natural abundance information to predict taxon-specific viability and iteratively constrain DTE experimental design to improve cultivation success. Cultivated bacterioplankton representatives from diverse lineages and locations are essential for microbiology, but the large majority of taxa either remain uncultivated or lack isolates from diverse geographic locales. We paired large-scale dilution-to-extinction (DTE) cultivation with microbial community analysis and modeling to expand the phylogenetic and geographic diversity of cultivated bacterioplankton and to evaluate DTE cultivation success. Here, we report results from 17 DTE experiments totaling 7,820 individual incubations over 3 years, yielding 328 repeatably transferable isolates. Comparison of isolates to microbial community data for source waters indicated that we successfully isolated 5% of the observed bacterioplankton community throughout the study; 43% and 26% of our isolates matched operational taxonomic units and amplicon single-nucleotide variants, respectively, within the top 50 most abundant taxa. Isolates included those from previously uncultivated clades such as SAR11 LD12 and Actinobacteria acIV, as well as geographically novel members from other ecologically important groups like SAR11 subclade IIIa, SAR116, and others, providing isolates in eight putatively new genera and seven putatively new species. Using a newly developed DTE cultivation model, we evaluated taxon viability by comparing relative abundance with cultivation success. The model (i) revealed the minimum attempts required for successful isolation of taxa amenable to growth on our media and (ii) identified possible subpopulation viability variation in abundant taxa such as SAR11 that likely impacts cultivation success. By incorporating viability in experimental design, we can now statistically constrain the effort necessary for successful cultivation of specific taxa on a defined medium. IMPORTANCE Even before the coining of the term “great plate count anomaly” in the 1980s, scientists had noted the discrepancy between the number of microorganisms observed under the microscope and the number of colonies that grew on traditional agar media. New cultivation approaches have reduced this disparity, resulting in the isolation of some of the “most wanted” bacterial lineages. Nevertheless, the vast majority of microorganisms remain uncultured, hampering progress toward answering fundamental biological questions about many important microorganisms. Furthermore, few studies have evaluated the underlying factors influencing cultivation success, limiting our ability to improve cultivation efficacy. Our work details the use of dilution-to-extinction (DTE) cultivation to expand the phylogenetic and geographic diversity of available axenic cultures. We also provide a new model of the DTE approach that uses cultivation results and natural abundance information to predict taxon-specific viability and iteratively constrain DTE experimental design to improve cultivation success.
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