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Chou L, Grefenstette N, Borges S, Caro T, Catalano E, Harman CE, McKaig J, Raj CG, Trubl G, Young A. Chapter 8: Searching for Life Beyond Earth. ASTROBIOLOGY 2024; 24:S164-S185. [PMID: 38498822 DOI: 10.1089/ast.2021.0104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
The search for life beyond Earth necessitates a rigorous and comprehensive examination of biosignatures, the types of observable imprints that life produces. These imprints and our ability to detect them with advanced instrumentation hold the key to our understanding of the presence and abundance of life in the universe. Biosignatures are the chemical or physical features associated with past or present life and may include the distribution of elements and molecules, alone or in combination, as well as changes in structural components or physical processes that would be distinct from an abiotic background. The scientific and technical strategies used to search for life on other planets include those that can be conducted in situ to planetary bodies and those that could be observed remotely. This chapter discusses numerous strategies that can be employed to look for biosignatures directly on other planetary bodies using robotic exploration including those that have been deployed to other planetary bodies, are currently being developed for flight, or will become a critical technology on future missions. Search strategies for remote observations using current and planned ground-based and space-based telescopes are also described. Evidence from spectral absorption, emission, or transmission features can be used to search for remote biosignatures and technosignatures. Improving our understanding of biosignatures, their production, transformation, and preservation on Earth can enhance our search efforts to detect life on other planets.
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Affiliation(s)
- Luoth Chou
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Center for Space Sciences and Technology, University of Maryland, Baltimore, Maryland, USA
- Georgetown University, Washington, DC, USA
| | - Natalie Grefenstette
- Santa Fe Institute, Santa Fe, New Mexico, USA
- Blue Marble Space Institute of Science, Seattle, Washington, USA
| | | | - Tristan Caro
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado, USA
| | - Enrico Catalano
- Sant'Anna School of Advanced Studies, The BioRobotics Institute, Pisa, Italy
| | | | - Jordan McKaig
- Georgia Institute of Technology, Atlanta, Georgia, USA
| | | | - Gareth Trubl
- Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Amber Young
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Northern Arizona University, Flagstaff, Arizona, USA
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2
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Vera-Gargallo B, Hernández M, Dumont MG, Ventosa A. Thrive or survive: prokaryotic life in hypersaline soils. ENVIRONMENTAL MICROBIOME 2023; 18:17. [PMID: 36915176 PMCID: PMC10012753 DOI: 10.1186/s40793-023-00475-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Soil services are central to life on the planet, with microorganisms as their main drivers. Thus, the evaluation of soil quality requires an understanding of the principles and factors governing microbial dynamics within it. High salt content is a constraint for life affecting more than 900 million hectares of land, a number predicted to rise at an alarming rate due to changing climate. Nevertheless, little is known about how microbial life unfolds in these habitats. In this study, DNA stable-isotope probing (DNA-SIP) with 18O-water was used to determine for the first time the taxa able to grow in hypersaline soil samples (ECe = 97.02 dS/m). We further evaluated the role of light on prokaryotes growth in this habitat. RESULTS We detected growth of both archaea and bacteria, with taxon-specific growth patterns providing insights into the drivers of success in saline soils. Phylotypes related to extreme halophiles, including haloarchaea and Salinibacter, which share an energetically efficient mechanism for salt adaptation (salt-in strategy), dominated the active community. Bacteria related to moderately halophilic and halotolerant taxa, such as Staphylococcus, Aliifodinibius, Bradymonadales or Chitinophagales also grew during the incubations, but they incorporated less heavy isotope. Light did not stimulate prokaryotic photosynthesis but instead restricted the growth of most bacteria and reduced the diversity of archaea that grew. CONCLUSIONS The results of this study suggest that life in saline soils is energetically expensive and that soil heterogeneity and traits such as exopolysaccharide production or predation may support growth in hypersaline soils. The contribution of phototrophy to supporting the heterotrophic community in saline soils remains unclear. This study paves the way toward a more comprehensive understanding of the functioning of these environments, which is fundamental to their management. Furthermore, it illustrates the potential of further research in saline soils to deepen our understanding of the effect of salinity on microbial communities.
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Affiliation(s)
- Blanca Vera-Gargallo
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, 41012, Sevilla, Spain
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Marcela Hernández
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Marc G Dumont
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, 41012, Sevilla, Spain.
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3
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Orsi WD. Quantitative microbial ecology: Future challenges and opportunities. Environ Microbiol 2023; 25:91-96. [PMID: 36163700 DOI: 10.1111/1462-2920.16204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 09/08/2022] [Indexed: 01/21/2023]
Affiliation(s)
- William D Orsi
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,GeoBio-CenterLMU, Ludwig-Maximilians-Universität München, Munich, Germany
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4
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Nuccio EE, Blazewicz SJ, Lafler M, Campbell AN, Kakouridis A, Kimbrel JA, Wollard J, Vyshenska D, Riley R, Tomatsu A, Hestrin R, Malmstrom RR, Firestone M, Pett-Ridge J. HT-SIP: a semi-automated stable isotope probing pipeline identifies cross-kingdom interactions in the hyphosphere of arbuscular mycorrhizal fungi. MICROBIOME 2022; 10:199. [PMID: 36434737 PMCID: PMC9700909 DOI: 10.1186/s40168-022-01391-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Linking the identity of wild microbes with their ecophysiological traits and environmental functions is a key ambition for microbial ecologists. Of many techniques that strive for this goal, Stable-isotope probing-SIP-remains among the most comprehensive for studying whole microbial communities in situ. In DNA-SIP, actively growing microorganisms that take up an isotopically heavy substrate build heavier DNA, which can be partitioned by density into multiple fractions and sequenced. However, SIP is relatively low throughput and requires significant hands-on labor. We designed and tested a semi-automated, high-throughput SIP (HT-SIP) pipeline to support well-replicated, temporally resolved amplicon and metagenomics experiments. We applied this pipeline to a soil microhabitat with significant ecological importance-the hyphosphere zone surrounding arbuscular mycorrhizal fungal (AMF) hyphae. AMF form symbiotic relationships with most plant species and play key roles in terrestrial nutrient and carbon cycling. RESULTS Our HT-SIP pipeline for fractionation, cleanup, and nucleic acid quantification of density gradients requires one-sixth of the hands-on labor compared to manual SIP and allows 16 samples to be processed simultaneously. Automated density fractionation increased the reproducibility of SIP gradients compared to manual fractionation, and we show adding a non-ionic detergent to the gradient buffer improved SIP DNA recovery. We applied HT-SIP to 13C-AMF hyphosphere DNA from a 13CO2 plant labeling study and created metagenome-assembled genomes (MAGs) using high-resolution SIP metagenomics (14 metagenomes per gradient). SIP confirmed the AMF Rhizophagus intraradices and associated MAGs were highly enriched (10-33 atom% 13C), even though the soils' overall enrichment was low (1.8 atom% 13C). We assembled 212 13C-hyphosphere MAGs; the hyphosphere taxa that assimilated the most AMF-derived 13C were from the phyla Myxococcota, Fibrobacterota, Verrucomicrobiota, and the ammonia-oxidizing archaeon genus Nitrososphaera. CONCLUSIONS Our semi-automated HT-SIP approach decreases operator time and improves reproducibility by targeting the most labor-intensive steps of SIP-fraction collection and cleanup. We illustrate this approach in a unique and understudied soil microhabitat-generating MAGs of actively growing microbes living in the AMF hyphosphere (without plant roots). The MAGs' phylogenetic composition and gene content suggest predation, decomposition, and ammonia oxidation may be key processes in hyphosphere nutrient cycling. Video Abstract.
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Affiliation(s)
- Erin E. Nuccio
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Steven J. Blazewicz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Marissa Lafler
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Ashley N. Campbell
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Anne Kakouridis
- Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
- Department of Environmental Science Policy and Management, University of California, Berkeley, CA USA
| | - Jeffrey A. Kimbrel
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | - Jessica Wollard
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
| | | | | | | | - Rachel Hestrin
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA USA
| | | | - Mary Firestone
- Department of Environmental Science Policy and Management, University of California, Berkeley, CA USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA USA
- Life & Environmental Sciences Department, University of California Merced, Merced, CA USA
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5
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Täumer J, Marhan S, Groß V, Jensen C, Kuss AW, Kolb S, Urich T. Linking transcriptional dynamics of CH 4-cycling grassland soil microbiomes to seasonal gas fluxes. THE ISME JOURNAL 2022; 16:1788-1797. [PMID: 35388141 PMCID: PMC9213473 DOI: 10.1038/s41396-022-01229-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 03/07/2022] [Accepted: 03/21/2022] [Indexed: 11/09/2022]
Abstract
Soil CH4 fluxes are driven by CH4-producing and -consuming microorganisms that determine whether soils are sources or sinks of this potent greenhouse gas. To date, a comprehensive understanding of underlying microbiome dynamics has rarely been obtained in situ. Using quantitative metatranscriptomics, we aimed to link CH4-cycling microbiomes to net surface CH4 fluxes throughout a year in two grassland soils. CH4 fluxes were highly dynamic: both soils were net CH4 sources in autumn and winter and sinks in spring and summer, respectively. Correspondingly, methanogen mRNA abundances per gram soil correlated well with CH4 fluxes. Methanotroph to methanogen mRNA ratios were higher in spring and summer, when the soils acted as net CH4 sinks. CH4 uptake was associated with an increased proportion of USCα and γ pmoA and pmoA2 transcripts. We assume that methanogen transcript abundance may be useful to approximate changes in net surface CH4 emissions from grassland soils. High methanotroph to methanogen ratios would indicate CH4 sink properties. Our study links for the first time the seasonal transcriptional dynamics of CH4-cycling soil microbiomes to gas fluxes in situ. It suggests mRNA transcript abundances as promising indicators of dynamic ecosystem-level processes.
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Affiliation(s)
- Jana Täumer
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Sven Marhan
- Institute of Soil Science and Land Evaluation, Soil Biology Department, University of Hohenheim, Stuttgart, Germany
| | - Verena Groß
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Corinna Jensen
- Human Molecular Genetics Group, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Andreas W Kuss
- Human Molecular Genetics Group, Department of Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Steffen Kolb
- RA Landscape Functioning, Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany.,Thaer Institute, Faculty of Life Sciences, Humboldt University of Berlin, Berlin, Germany
| | - Tim Urich
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany.
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6
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Hayer M, Wymore AS, Hungate BA, Schwartz E, Koch BJ, Marks JC. Microbes on decomposing litter in streams: entering on the leaf or colonizing in the water? THE ISME JOURNAL 2022; 16:717-725. [PMID: 34580429 PMCID: PMC8857200 DOI: 10.1038/s41396-021-01114-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 08/29/2021] [Accepted: 09/09/2021] [Indexed: 01/04/2023]
Abstract
When leaves fall in rivers, microbial decomposition commences within hours. Microbial assemblages comprising hundreds of species of fungi and bacteria can vary with stream conditions, leaf litter species, and decomposition stage. In terrestrial ecosystems, fungi and bacteria that enter soils with dead leaves often play prominent roles in decomposition, but their role in aquatic decomposition is less known. Here, we test whether fungi and bacteria that enter streams on senesced leaves are growing during decomposition and compare their abundances and growth to bacteria and fungi that colonize leaves in the water. We employ quantitative stable isotope probing to identify growing microbes across four leaf litter species and two decomposition times. We find that most of the growing fungal species on decomposing leaves enter the water with the leaf, whereas most growing bacteria colonize from the water column. Results indicate that the majority of bacteria found on litter are growing, whereas the majority of fungi are dormant. Both bacterial and fungal assemblages differed with leaf type on the dried leaves and throughout decomposition. This research demonstrates the importance of fungal species that enter with the leaf on aquatic decomposition and the prominence of bacteria that colonize decomposing leaves in the water.
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Affiliation(s)
- Michaela Hayer
- Center for Ecosystem Science and Society, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA.
| | - Adam S. Wymore
- grid.167436.10000 0001 2192 7145Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824 USA
| | - Bruce A. Hungate
- grid.261120.60000 0004 1936 8040Center for Ecosystem Science and Society, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011 USA
| | - Egbert Schwartz
- grid.261120.60000 0004 1936 8040Center for Ecosystem Science and Society, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011 USA
| | - Benjamin J. Koch
- grid.261120.60000 0004 1936 8040Center for Ecosystem Science and Society, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011 USA
| | - Jane C. Marks
- grid.261120.60000 0004 1936 8040Center for Ecosystem Science and Society, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011 USA
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7
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Borer B, Or D. Bacterial age distribution in soil - Generational gaps in adjacent hot and cold spots. PLoS Comput Biol 2022; 18:e1009857. [PMID: 35213536 PMCID: PMC8906644 DOI: 10.1371/journal.pcbi.1009857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 03/09/2022] [Accepted: 01/23/2022] [Indexed: 11/25/2022] Open
Abstract
Resource patchiness and aqueous phase fragmentation in soil may induce large differences local growth conditions at submillimeter scales. These are translated to vast differences in bacterial age from cells dividing every thirty minutes in close proximity to plant roots to very old cells experiencing negligible growth in adjacent nutrient poor patches. In this study, we link bacterial population demographics with localized soil and hydration conditions to predict emerging generation time distributions and estimate mean bacterial cell ages using mechanistic and heuristic models of bacterial life in soil. Results show heavy-tailed distributions of generation times that resemble a power law for certain conditions, suggesting that we may find bacterial cells of vastly different ages living side by side within small soil volumes. Our results imply that individual bacteria may exist concurrently with all of their ancestors, resulting in an archive of bacterial cells with traits that have been gained (and lost) throughout time-a feature unique to microbial life. This reservoir of bacterial strains and the potential for the reemergence of rare strains with specific functions may be critical for ecosystem stability and function.
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Affiliation(s)
| | - Dani Or
- ETH Zurich, Zurich, Switzerland
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8
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Microbial Taxon-Specific Isotope Incorporation with DNA Quantitative Stable Isotope Probing. Methods Mol Biol 2020; 2046:137-149. [PMID: 31407302 DOI: 10.1007/978-1-4939-9721-3_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Quantitative stable isotope probing (qSIP) measures rates of taxon-specific element assimilation in intact microbial communities, utilizing substrates labeled with a heavy isotope.The laboratory protocol for qSIP is nearly identical to that for conventional stable isotope probing, with two key additions: (1) in qSIP, qPCR measurements are conducted on each density fraction recovered after isopycnic separation, and (2) in qSIP, multiple density fractions are sequenced spanning the entire range of densities over which nucleic acids were recovered. qSIP goes beyond identifying taxa assimilating a substrate, as it also allows for measuring that assimilation for each taxon within a given microbial community. Here, we describe an analysis process necessary to determine atom fraction excess of a heavy stable isotope added to an environmental sample for a given taxon's DNA.
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9
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Lashkarboluki R, Mallah M. A rate-based dynamic model of multicomponent distillation column for 18O isotope separation. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.115745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Stable Isotope Probing of Microorganisms in Environmental Samples with H 218O. Methods Mol Biol 2019; 2046:129-136. [PMID: 31407301 DOI: 10.1007/978-1-4939-9721-3_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
We describe a protocol for investigating microbial growth in environmental samples via stable isotope probing (SIP) with H218O. Water is a universal substrate for all microorganisms and replication is required for DNA to become labeled with 18O. By measuring how much the DNA of each taxon becomes enriched with 18O when an environmental sample is incubated with H218O, it is feasible to quantify that population's DNA replication rate, which is a proxy for growth.
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11
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Kumar SS, Ghosh AR. Assessment of bacterial viability: a comprehensive review on recent advances and challenges. Microbiology (Reading) 2019; 165:593-610. [DOI: 10.1099/mic.0.000786] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Shravanthi S. Kumar
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
| | - Asit Ranjan Ghosh
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
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12
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Vuillemin A, Wankel SD, Coskun ÖK, Magritsch T, Vargas S, Estes ER, Spivack AJ, Smith DC, Pockalny R, Murray RW, D’Hondt S, Orsi WD. Archaea dominate oxic subseafloor communities over multimillion-year time scales. SCIENCE ADVANCES 2019; 5:eaaw4108. [PMID: 31223656 PMCID: PMC6584578 DOI: 10.1126/sciadv.aaw4108] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 05/10/2019] [Indexed: 05/31/2023]
Abstract
Ammonia-oxidizing archaea (AOA) dominate microbial communities throughout oxic subseafloor sediment deposited over millions of years in the North Atlantic Ocean. Rates of nitrification correlated with the abundance of these dominant AOA populations, whose metabolism is characterized by ammonia oxidation, mixotrophic utilization of organic nitrogen, deamination, and the energetically efficient chemolithoautotrophic hydroxypropionate/hydroxybutyrate carbon fixation cycle. These AOA thus have the potential to couple mixotrophic and chemolithoautotrophic metabolism via mixotrophic deamination of organic nitrogen, followed by oxidation of the regenerated ammonia for additional energy to fuel carbon fixation. This metabolic feature likely reduces energy loss and improves AOA fitness under energy-starved, oxic conditions, thereby allowing them to outcompete other taxa for millions of years.
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Affiliation(s)
- Aurèle Vuillemin
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - Scott D. Wankel
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Ömer K. Coskun
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - Tobias Magritsch
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - Sergio Vargas
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - Emily R. Estes
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE 19958, USA
| | - Arthur J. Spivack
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA
| | - David C. Smith
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA
| | - Robert Pockalny
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA
| | - Richard W. Murray
- Department of Earth and Environment, Boston University, Boston, MA 02215, USA
| | - Steven D’Hondt
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA
| | - William D. Orsi
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
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13
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Quantifying population-specific growth in benthic bacterial communities under low oxygen using H 218O. ISME JOURNAL 2019; 13:1546-1559. [PMID: 30783213 PMCID: PMC6776007 DOI: 10.1038/s41396-019-0373-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/26/2019] [Accepted: 01/31/2019] [Indexed: 01/09/2023]
Abstract
The benthos in estuarine environments often experiences periods of regularly occurring hypoxic and anoxic conditions, dramatically impacting biogeochemical cycles. How oxygen depletion affects the growth of specific uncultivated microbial populations within these diverse benthic communities, however, remains poorly understood. Here, we applied H218O quantitative stable isotope probing (qSIP) in order to quantify the growth of diverse, uncultured bacterial populations in response to low oxygen concentrations in estuarine sediments. Over the course of 7- and 28-day incubations with redox conditions spanning from hypoxia to euxinia (sulfidic), 18O labeling of bacterial populations exhibited different patterns consistent with micro-aerophilic, anaerobic, facultative anaerobic, and aerotolerant anaerobic growth. 18O-labeled populations displaying anaerobic growth had a significantly non-random phylogenetic distribution, exhibited by numerous clades currently lacking cultured representatives within the Planctomycetes, Actinobacteria, Latescibacteria, Verrucomicrobia, and Acidobacteria. Genes encoding the beta-subunit of the dissimilatory sulfate reductase (dsrB) became 18O labeled only during euxinic conditions. Sequencing of these 18O-labeled dsrB genes showed that Acidobacteria were the dominant group of growing sulfate-reducing bacteria, highlighting their importance for sulfur cycling in estuarine sediments. Our findings provide the first experimental constraints on the redox conditions underlying increased growth in several groups of "microbial dark matter", validating hypotheses put forth by earlier metagenomic studies.
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14
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Koch BJ, McHugh TA, Hayer M, Schwartz E, Blazewicz SJ, Dijkstra P, Gestel N, Marks JC, Mau RL, Morrissey EM, Pett‐Ridge J, Hungate BA. Estimating taxon‐specific population dynamics in diverse microbial communities. Ecosphere 2018. [DOI: 10.1002/ecs2.2090] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Benjamin J. Koch
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
| | - Theresa A. McHugh
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
- Department of Biological Sciences Northern Arizona University Flagstaff Arizona 86011 USA
| | - Steven J. Blazewicz
- Physical and Life Sciences Directorate Lawrence Livermore National Laboratory Livermore California 94550 USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
- Department of Biological Sciences Northern Arizona University Flagstaff Arizona 86011 USA
| | - Natasja Gestel
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
| | - Jane C. Marks
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
- Department of Biological Sciences Northern Arizona University Flagstaff Arizona 86011 USA
| | - Rebecca L. Mau
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
| | - Ember M. Morrissey
- Division of Plant and Soil Sciences West Virginia University Morgantown West Virginia 26506 USA
| | - Jennifer Pett‐Ridge
- Physical and Life Sciences Directorate Lawrence Livermore National Laboratory Livermore California 94550 USA
| | - Bruce A. Hungate
- Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86011 USA
- Department of Biological Sciences Northern Arizona University Flagstaff Arizona 86011 USA
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15
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Singer E, Wagner M, Woyke T. Capturing the genetic makeup of the active microbiome in situ. THE ISME JOURNAL 2017; 11:1949-1963. [PMID: 28574490 PMCID: PMC5563950 DOI: 10.1038/ismej.2017.59] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/02/2017] [Accepted: 03/10/2017] [Indexed: 12/21/2022]
Abstract
More than any other technology, nucleic acid sequencing has enabled microbial ecology studies to be complemented with the data volumes necessary to capture the extent of microbial diversity and dynamics in a wide range of environments. In order to truly understand and predict environmental processes, however, the distinction between active, inactive and dead microbial cells is critical. Also, experimental designs need to be sensitive toward varying population complexity and activity, and temporal as well as spatial scales of process rates. There are a number of approaches, including single-cell techniques, which were designed to study in situ microbial activity and that have been successively coupled to nucleic acid sequencing. The exciting new discoveries regarding in situ microbial activity provide evidence that future microbial ecology studies will indispensably rely on techniques that specifically capture members of the microbiome active in the environment. Herein, we review those currently used activity-based approaches that can be directly linked to shotgun nucleic acid sequencing, evaluate their relevance to ecology studies, and discuss future directions.
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Affiliation(s)
- Esther Singer
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Michael Wagner
- University of Vienna, Department of Microbial Ecology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Tanja Woyke
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
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Kästner M, Nowak KM, Miltner A, Schäffer A. (Multiple) Isotope probing approaches to trace the fate of environmental chemicals and the formation of non-extractable ‘bound’ residues. Curr Opin Biotechnol 2016; 41:73-82. [DOI: 10.1016/j.copbio.2016.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 10/21/2022]
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Lueders T, Dumont MG, Bradford L, Manefield M. RNA-stable isotope probing: from carbon flow within key microbiota to targeted transcriptomes. Curr Opin Biotechnol 2016; 41:83-89. [PMID: 27269505 DOI: 10.1016/j.copbio.2016.05.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 04/27/2016] [Accepted: 05/05/2016] [Indexed: 10/21/2022]
Abstract
Stable isotope probing of RNA has enthused researchers right from its first introduction in 2002. The concept of a labelling-based detection of process-targeted microbes independent of cellular replication or growth has allowed for a much more direct handle on functionally relevant microbiota than by labelling of other biomarkers. This has led to a widespread application of the technology, and breakthroughs in our understanding of carbon flow in natural microbiomes, autotrophic and heterotrophic physiologies, microbial food webs, host-microbe interactions and environmental biotechnology. Recent studies detecting labelled mRNA demonstrate that RNA-SIP is not limited to the analysis of rRNA, but is currently developing towards an approach for accessing targeted transcriptomes. In combination with next-generation sequencing and other methodological advances, RNA-SIP will continue to deliver invaluable insights into the functioning of microbial communities.
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Affiliation(s)
- Tillmann Lueders
- Helmholtz Zentrum München - German Research Center for Environmental Health, Institute for Groundwater Ecology, Neuherberg, Germany.
| | - Marc G Dumont
- Centre for Biological Sciences (CfBS), University of Southampton, Southampton, United Kingdom
| | - Lauren Bradford
- Helmholtz Zentrum München - German Research Center for Environmental Health, Institute for Groundwater Ecology, Neuherberg, Germany
| | - Mike Manefield
- Centre for Marine Bioinnovation, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
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