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Medvedeva S, Borrel G, Krupovic M, Gribaldo S. A compendium of viruses from methanogenic archaea reveals their diversity and adaptations to the gut environment. Nat Microbiol 2023; 8:2170-2182. [PMID: 37749252 DOI: 10.1038/s41564-023-01485-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 08/30/2023] [Indexed: 09/27/2023]
Abstract
Methanogenic archaea are major producers of methane, a potent greenhouse gas and biofuel, and are widespread in diverse environments, including the animal gut. The ecophysiology of methanogens is likely impacted by viruses, which remain, however, largely uncharacterized. Here we carried out a global investigation of viruses associated with all current diversity of methanogens by assembling an extensive CRISPR database consisting of 156,000 spacers. We report 282 high-quality (pro)viral and 205 virus-like/plasmid sequences assigned to hosts belonging to ten main orders of methanogenic archaea. Viruses of methanogens can be classified into 87 families, underscoring a still largely undiscovered genetic diversity. Viruses infecting gut-associated archaea provide evidence of convergence in adaptation with viruses infecting gut-associated bacteria. These viruses contain a large repertoire of lysin proteins that cleave archaeal pseudomurein and are enriched in glycan-binding domains (Ig-like/Flg_new) and diversity-generating retroelements. The characterization of this vast repertoire of viruses paves the way towards a better understanding of their role in regulating methanogen communities globally, as well as the development of much-needed genetic tools.
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Affiliation(s)
- Sofia Medvedeva
- Institut Pasteur, Université Paris Cité, Unit Evolutionary Biology of the Microbial Cell, Paris, France
| | - Guillaume Borrel
- Institut Pasteur, Université Paris Cité, Unit Evolutionary Biology of the Microbial Cell, Paris, France.
| | - Mart Krupovic
- Institut Pasteur, Université Paris Cité, Unit Archaeal Virology, Paris, France.
| | - Simonetta Gribaldo
- Institut Pasteur, Université Paris Cité, Unit Evolutionary Biology of the Microbial Cell, Paris, France.
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Ouboter HT, Arshad A, Berger S, Saucedo Sanchez JG, Op den Camp HJM, Jetten MSM, Welte CU, Kurth JM. Acetate and Acetyl-CoA Metabolism of ANME-2 Anaerobic Archaeal Methanotrophs. Appl Environ Microbiol 2023; 89:e0036723. [PMID: 37272802 PMCID: PMC10304654 DOI: 10.1128/aem.00367-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/15/2023] [Indexed: 06/06/2023] Open
Abstract
Acetyl-CoA synthetase (ACS) and acetate ligase (ACD) are widespread among microorganisms, including archaea, and play an important role in their carbon metabolism, although only a few of these enzymes have been characterized. Anaerobic methanotrophs (ANMEs) have been reported to convert methane anaerobically into CO2, polyhydroxyalkanoate, and acetate. Furthermore, it has been suggested that they might be able to use acetate for anabolism or aceticlastic methanogenesis. To better understand the potential acetate metabolism of ANMEs, we characterized an ACS from ANME-2a as well as an ACS and an ACD from ANME-2d. The conversion of acetate into acetyl-CoA (Vmax of 8.4 μmol mg-1 min-1 and Km of 0.7 mM acetate) by the monomeric 73.8-kDa ACS enzyme from ANME-2a was more favorable than the formation of acetate from acetyl-CoA (Vmax of 0.4 μmol mg-1 min-1 and Km of 0.2 mM acetyl-CoA). The monomeric 73.4-kDa ACS enzyme from ANME-2d had similar Vmax values for both directions (Vmax,acetate of 0.9 μmol mg-1 min-1 versus Vmax,acetyl-CoA of 0.3 μmol mg-1 min-1). The heterotetrameric ACD enzyme from ANME-2d was active solely in the acetate-producing direction. Batch incubations of an enrichment culture dominated by ANME-2d fed with 13C2-labeled acetate produced 3 μmol of [13C]methane in 7 days, suggesting that this anaerobic methanotroph might have the potential to reverse its metabolism and perform aceticlastic methanogenesis using ACS to activate acetate albeit at low rates (2 nmol g [dry weight]-1 min-1). Together, these results show that ANMEs may have the potential to use acetate for assimilation as well as to use part of the surplus acetate for methane production. IMPORTANCE Acetyl-CoA plays a key role in carbon metabolism and is found at the junction of many anabolic and catabolic reactions. This work describes the biochemical properties of ACS and ACD enzymes from ANME-2 archaea. This adds to our knowledge of archaeal ACS and ACD enzymes, only a few of which have been characterized to date. Furthermore, we validated the in situ activity of ACS in ANME-2d, showing the conversion of acetate into methane by an enrichment culture dominated by ANME-2d.
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Affiliation(s)
- Heleen T. Ouboter
- Radboud Institute of Biological and Environmental Sciences, Microbiology Cluster, Radboud University, Nijmegen, Netherlands
- Soehngen Institute of Anaerobic Microbiology, Nijmegen, Netherlands
| | - Arslan Arshad
- Radboud Institute of Biological and Environmental Sciences, Microbiology Cluster, Radboud University, Nijmegen, Netherlands
| | - Stefanie Berger
- Radboud Institute of Biological and Environmental Sciences, Microbiology Cluster, Radboud University, Nijmegen, Netherlands
- Soehngen Institute of Anaerobic Microbiology, Nijmegen, Netherlands
| | - Jesus Gerardo Saucedo Sanchez
- Radboud Institute of Biological and Environmental Sciences, Microbiology Cluster, Radboud University, Nijmegen, Netherlands
| | - Huub J. M. Op den Camp
- Radboud Institute of Biological and Environmental Sciences, Microbiology Cluster, Radboud University, Nijmegen, Netherlands
| | - Mike S. M. Jetten
- Radboud Institute of Biological and Environmental Sciences, Microbiology Cluster, Radboud University, Nijmegen, Netherlands
- Soehngen Institute of Anaerobic Microbiology, Nijmegen, Netherlands
| | - Cornelia U. Welte
- Radboud Institute of Biological and Environmental Sciences, Microbiology Cluster, Radboud University, Nijmegen, Netherlands
- Soehngen Institute of Anaerobic Microbiology, Nijmegen, Netherlands
| | - Julia M. Kurth
- Radboud Institute of Biological and Environmental Sciences, Microbiology Cluster, Radboud University, Nijmegen, Netherlands
- Soehngen Institute of Anaerobic Microbiology, Nijmegen, Netherlands
- Microcosm Earth Center, Philipps-Universität Marburg and Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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Glodowska M, Ma Y, Smith G, Kappler A, Jetten M, Welte CU. Nitrate leaching and its implication for Fe and As mobility in a Southeast Asian aquifer. FEMS Microbiol Ecol 2023; 99:fiad025. [PMID: 36918194 PMCID: PMC10038221 DOI: 10.1093/femsec/fiad025] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/14/2023] [Accepted: 03/13/2023] [Indexed: 03/15/2023] Open
Abstract
The drinking water quality in Southeast Asia is at risk due to arsenic (As) groundwater contamination. Intensive use of fertilizers may lead to nitrate (NO3-) leaching into aquifers, yet very little is known about its effect on iron (Fe) and As mobility in water. We ran a set of microcosm experiments using aquifer sediment from Vietnam supplemented with 15NO3- and 13CH4. To assess the effect of nitrate-dependent anaerobic methane oxidation (N-DAMO) we also inoculated the sediment with two different N-DAMO enrichment cultures. We found that native microorganisms and both N-DAMO enrichments could efficiently consume all NO3- in 5 days. However, CH4 oxidation was observed only in the inoculated microcosms, suggesting that the native microbial community did not perform N-DAMO. In uninoculated microcosms, NO3- was preferentially used over Fe(III) as an electron acceptor and consequently inhibited Fe(III) reduction and As mobilization. The addition of N-DAMO enrichment cultures led to Fe(III) reduction and stimulated As and Mn release into the water. The archaeal community in all treatments was dominated by Ca. Methanoperedens while the bacterial community consisted of various denitrifiers. Our results suggest that input of N fertilizers to the aquifer decreases As mobility and that CH4 cannot serve as an electron donor for NO3- reduction.
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Affiliation(s)
- Martyna Glodowska
- Department of Microbiology, RIBES, Radboud University, 6525, Nijmegen, the Netherlands
| | - Yinxiao Ma
- Department of Microbiology, RIBES, Radboud University, 6525, Nijmegen, the Netherlands
| | - Garrett Smith
- Department of Microbiology, RIBES, Radboud University, 6525, Nijmegen, the Netherlands
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, 72074, Tübingen, Germany
| | - Mike Jetten
- Department of Microbiology, RIBES, Radboud University, 6525, Nijmegen, the Netherlands
| | - Cornelia U Welte
- Department of Microbiology, RIBES, Radboud University, 6525, Nijmegen, the Netherlands
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Tandem repeats in giant archaeal Borg elements undergo rapid evolution and create new intrinsically disordered regions in proteins. PLoS Biol 2023; 21:e3001980. [PMID: 36701369 PMCID: PMC9879509 DOI: 10.1371/journal.pbio.3001980] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 12/23/2022] [Indexed: 01/27/2023] Open
Abstract
Borgs are huge, linear extrachromosomal elements associated with anaerobic methane-oxidizing archaea. Striking features of Borg genomes are pervasive tandem direct repeat (TR) regions. Here, we present six new Borg genomes and investigate the characteristics of TRs in all ten complete Borg genomes. We find that TR regions are rapidly evolving, recently formed, arise independently, and are virtually absent in host Methanoperedens genomes. Flanking partial repeats and A-enriched character constrain the TR formation mechanism. TRs can be in intergenic regions, where they might serve as regulatory RNAs, or in open reading frames (ORFs). TRs in ORFs are under very strong selective pressure, leading to perfect amino acid TRs (aaTRs) that are commonly intrinsically disordered regions. Proteins with aaTRs are often extracellular or membrane proteins, and functionally similar or homologous proteins often have aaTRs composed of the same amino acids. We propose that Borg aaTR-proteins functionally diversify Methanoperedens and all TRs are crucial for specific Borg-host associations and possibly cospeciation.
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