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Nisson DM, Walters CC, Chacón-Patiño ML, Weisbrod CR, Kieft TL, Sherwood Lollar B, Warr O, Castillo J, Perl SM, Cason ED, Freifeld BM, Onstott TC. Radiolytically reworked Archean organic matter in a habitable deep ancient high-temperature brine. Nat Commun 2023; 14:6163. [PMID: 37789019 PMCID: PMC10547683 DOI: 10.1038/s41467-023-41900-8] [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: 02/07/2023] [Accepted: 09/20/2023] [Indexed: 10/05/2023] Open
Abstract
Investigations of abiotic and biotic contributions to dissolved organic carbon (DOC) are required to constrain microbial habitability in continental subsurface fluids. Here we investigate a large (101-283 mg C/L) DOC pool in an ancient (>1Ga), high temperature (45-55 °C), low biomass (102-104 cells/mL), and deep (3.2 km) brine from an uranium-enriched South African gold mine. Excitation-emission matrices (EEMs), negative electrospray ionization (-ESI) 21 tesla Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and amino acid analyses suggest the brine DOC is primarily radiolytically oxidized kerogen-rich shales or reefs, methane and ethane, with trace amounts of C3-C6 hydrocarbons and organic sulfides. δ2H and δ13C of C1-C3 hydrocarbons are consistent with abiotic origins. These findings suggest water-rock processes control redox and C cycling, helping support a meagre, slow biosphere over geologic time. A radiolytic-driven, habitable brine may signal similar settings are good targets in the search for life beyond Earth.
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Affiliation(s)
- Devan M Nisson
- Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA.
| | | | | | - Chad R Weisbrod
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Thomas L Kieft
- Department of Biology, New Mexico Institute of Mining and Technology, Socorro, NM, 87801, USA
| | - Barbara Sherwood Lollar
- Department of Earth Sciences, University of Toronto, Toronto, ON, M5S 3B1, Canada
- Institut de Physique du Globe de Paris (IPGP), Université Paris Cité, 1 rue Jussieu, 75005, Paris, France
| | - Oliver Warr
- Department of Earth Sciences, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Julio Castillo
- Department of Microbiology and Biochemistry, University of the Free State, Bloemfontein, 9300, South Africa
| | - Scott M Perl
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Errol D Cason
- Department of Animal Sciences, University of the Free State, Bloemfontein, 9300, South Africa
| | | | - Tullis C Onstott
- Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA
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Beulig F, Schubert F, Adhikari RR, Glombitza C, Heuer VB, Hinrichs KU, Homola KL, Inagaki F, Jørgensen BB, Kallmeyer J, Krause SJE, Morono Y, Sauvage J, Spivack AJ, Treude T. Rapid metabolism fosters microbial survival in the deep, hot subseafloor biosphere. Nat Commun 2022; 13:312. [PMID: 35078973 PMCID: PMC8789916 DOI: 10.1038/s41467-021-27802-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 12/10/2021] [Indexed: 11/25/2022] Open
Abstract
A fourth of the global seabed sediment volume is buried at depths where temperatures exceed 80 °C, a previously proposed thermal barrier for life in the subsurface. Here, we demonstrate, utilizing an extensive suite of radiotracer experiments, the prevalence of active methanogenic and sulfate-reducing populations in deeply buried marine sediment from the Nankai Trough subduction zone, heated to extreme temperature (up to ~120 °C). The small microbial community subsisted with high potential cell-specific rates of energy metabolism, which approach the rates of active surface sediments and laboratory cultures. Our discovery is in stark contrast to the extremely low metabolic rates otherwise observed in the deep subseafloor. As cells appear to invest most of their energy to repair thermal cell damage in the hot sediment, they are forced to balance delicately between subsistence near the upper temperature limit for life and a rich supply of substrates and energy from thermally driven reactions of the sedimentary organic matter. In the deep sedimentary biosphere, 80 °C has been proposed as an upper thermal barrier for life. Using a suite of radiotracer experiments, this study reports active methanogenic and sulfate-reducing microbial populations with high cell-specific metabolic rates in deeply buried marine sediments from the Nankai Trough subduction zone, which reach temperatures up to 120 °C.
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Evolutionary stasis of a deep subsurface microbial lineage. THE ISME JOURNAL 2021; 15:2830-2842. [PMID: 33824425 PMCID: PMC8443664 DOI: 10.1038/s41396-021-00965-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 02/26/2021] [Accepted: 03/15/2021] [Indexed: 02/01/2023]
Abstract
Sulfate-reducing bacteria Candidatus Desulforudis audaxviator (CDA) were originally discovered in deep fracture fluids accessed via South African gold mines and have since been found in geographically widespread deep subsurface locations. In order to constrain models for subsurface microbial evolution, we compared CDA genomes from Africa, North America and Eurasia using single cell genomics. Unexpectedly, 126 partial single amplified genomes from the three continents, a complete genome from of an isolate from Eurasia, and metagenome-assembled genomes from Africa and Eurasia shared >99.2% average nucleotide identity, low frequency of SNP's, and near-perfectly conserved prophages and CRISPRs. Our analyses reject sample cross-contamination, recent natural dispersal, and unusually strong purifying selection as likely explanations for these unexpected results. We therefore conclude that the analyzed CDA populations underwent only minimal evolution since their physical separation, potentially as far back as the breakup of Pangea between 165 and 55 Ma ago. High-fidelity DNA replication and repair mechanisms are the most plausible explanation for the highly conserved genome of CDA. CDA presents a stark contrast to the current model organisms in microbial evolutionary studies, which often develop adaptive traits over far shorter periods of time.
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Liang R, Robb FT, Onstott TC. Aspartic acid racemization and repair in the survival and recovery of hyperthermophiles after prolonged starvation at high temperature. FEMS Microbiol Ecol 2021; 97:6330453. [PMID: 34323966 DOI: 10.1093/femsec/fiab112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/27/2021] [Indexed: 11/14/2022] Open
Abstract
Long-term survivability is well-known for microorganisms in nutrient-depleted environments, but the damage accrued by proteins and the associated repair processes during the starvation and recovery phase of microbial life still remain enigmatic. We focused on aspartic acid (Asp) racemization and repair in the survival of Pyrococcus furiosus and Thermococcus litoralis under starvation conditions at high temperature. Despite the dramatic decrease of viability over time, 0.002% of P. furiosus cells (2.1×103 cells/mL) and 0.23% of T. litoralis cells (2.3×105 cells/mL) remained viable after 25 and 50 days, respectively. The D/L Asp ratio in the starved cells was approximately half of those from the autoclaved cells, suggesting that the starving cells were capable of partially repairing racemized Asp. Transcriptomic analyses of the recovered cells of T. litoralis indicated that the gene encoding Protein-L-isoaspartate (D-aspartate) O-methyltransferase (PIMT) might be involved in the repair of damaged proteins by converting D-Asp back to L-Asp during the resuscitation of starved cells. Collectively, our results provided evidence that Asp underwent racemization in the surviving hyperthermophilic cells under starved conditions and PIMT played a critical role in the repair of abnormal aspartyl residues during the initial recovery of starved, yet still viable, cells.
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Affiliation(s)
- Renxing Liang
- Department of Geosciences, Princeton University, Princeton, New Jersey, 08544, USA
| | - Frank T Robb
- Institute of Marine and Environmental Technology, University of Maryland, Baltimore, Maryland, 21202, USA
- Department of Microbiology and Immunology, University of Maryland, Baltimore, Maryland, 21202, USA
| | - Tullis C Onstott
- Department of Geosciences, Princeton University, Princeton, New Jersey, 08544, USA
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Christie G, Setlow P. Bacillus spore germination: Knowns, unknowns and what we need to learn. Cell Signal 2020; 74:109729. [PMID: 32721540 DOI: 10.1016/j.cellsig.2020.109729] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/18/2020] [Accepted: 07/21/2020] [Indexed: 01/06/2023]
Abstract
How might a microbial cell that is entirely metabolically dormant - and which has the ability to remain so for extended periods of time - irreversibly commit itself to resuming vegetative growth within seconds of being exposed to certain amino acids or sugars? That this process takes place in the absence of any detectable ATP or de novo protein synthesis, and relies upon a pre-formed apparatus that is immobilised, respectively, in a semi-crystalline membrane or multi-layered proteinaceous coat, only exacerbates the challenge facing spores of Bacillales species when stimulated to germinate. Whereas the process by which spores are formed in response to nutrient starvation - sporulation - involves the orchestrated interplay between hundreds of distinct proteins, the process by which spores return to life - germination - is a much simpler affair, requiring a handful of receptor and channel proteins complemented with specialized peptidoglycan lysins. Despite this relative simplicity, and research effort spanning many decades, comprehensive understanding of key molecular and biochemical details and, in particular signal transduction mechanisms associated with spore germination, has remained elusive. In this review we provide an up to date overview of the field while identifying what we consider to be the key gaps in knowledge associated with germination of Bacillales spores, suggesting also technical approaches that may provide fresh insight to this unique biological process.
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Affiliation(s)
- Graham Christie
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 OAS, United Kingdom.
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA.
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