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Müller N, Timmers P, Plugge CM, Stams AJM, Schink B. Syntrophy in Methanogenic Degradation. (ENDO)SYMBIOTIC METHANOGENIC ARCHAEA 2018. [DOI: 10.1007/978-3-319-98836-8_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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152
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Singh R, Guzman MS, Bose A. Anaerobic Oxidation of Ethane, Propane, and Butane by Marine Microbes: A Mini Review. Front Microbiol 2017; 8:2056. [PMID: 29109712 PMCID: PMC5660070 DOI: 10.3389/fmicb.2017.02056] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 10/06/2017] [Indexed: 12/16/2022] Open
Abstract
The deep ocean and its sediments are a continuous source of non-methane short-chain alkanes (SCAs) including ethane, propane, and butane. Their high global warming potential, and contribution to local carbon and sulfur budgets has drawn significant scientific attention. Importantly, microbes can use gaseous alkanes and oxidize them to CO2, thus acting as effective biofilters. A relative decrease of these gases with a concomitant 13C enrichment of propane and n-butane in interstitial waters vs. the source suggests microbial anaerobic oxidation. The reported uncoupling of sulfate-reduction (SR) from anaerobic methane oxidation supports their microbial consumption. To date, strain BuS5 isolated from the sediments of Guaymas Basin, Gulf of California, is the only pure culture that can anaerobically degrade propane and n-butane. This organism belongs to a metabolically diverse cluster within the Deltaproteobacteria called Desulfosarcina/Desulfococcus. Other phylotypes involved in gaseous alkane degradation were identified based on stable-isotope labeling and fluorescence in-situ hybridization. A novel syntrophic association of the archaeal genus, Candidatus Syntrophoarchaeum, and a thermophilic SR bacterium, HotSeep-1 was recently discovered from the Guaymas basin, Gulf of California that can anaerobically oxidize n-butane. Strikingly, metagenomic data and the draft genomes of ca. Syntrophoarchaeum suggest that this organism uses a novel mechanism for n-butane oxidation, distinct from the well-established fumarate addition mechanism. These recent findings indicate that a lot remains to be understood about our understanding of anaerobic SCA degradation. This mini-review summarizes our current understanding of microbial anaerobic SCA degradation, and provides an outlook for future research.
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Affiliation(s)
- Rajesh Singh
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Michael S Guzman
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Arpita Bose
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
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153
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Affiliation(s)
- Derek R. Lovley
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003
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154
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Martin WF, Tielens AGM, Mentel M, Garg SG, Gould SB. The Physiology of Phagocytosis in the Context of Mitochondrial Origin. Microbiol Mol Biol Rev 2017; 81:e00008-17. [PMID: 28615286 PMCID: PMC5584316 DOI: 10.1128/mmbr.00008-17] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
How mitochondria came to reside within the cytosol of their host has been debated for 50 years. Though current data indicate that the last eukaryote common ancestor possessed mitochondria and was a complex cell, whether mitochondria or complexity came first in eukaryotic evolution is still discussed. In autogenous models (complexity first), the origin of phagocytosis poses the limiting step at eukaryote origin, with mitochondria coming late as an undigested growth substrate. In symbiosis-based models (mitochondria first), the host was an archaeon, and the origin of mitochondria was the limiting step at eukaryote origin, with mitochondria providing bacterial genes, ATP synthesis on internalized bioenergetic membranes, and mitochondrion-derived vesicles as the seed of the eukaryote endomembrane system. Metagenomic studies are uncovering new host-related archaeal lineages that are reported as complex or phagocytosing, although images of such cells are lacking. Here we review the physiology and components of phagocytosis in eukaryotes, critically inspecting the concept of a phagotrophic host. From ATP supply and demand, a mitochondrion-lacking phagotrophic archaeal fermenter would have to ingest about 34 times its body weight in prokaryotic prey to obtain enough ATP to support one cell division. It would lack chemiosmotic ATP synthesis at the plasma membrane, because phagocytosis and chemiosmosis in the same membrane are incompatible. It would have lived from amino acid fermentations, because prokaryotes are mainly protein. Its ATP yield would have been impaired relative to typical archaeal amino acid fermentations, which involve chemiosmosis. In contrast, phagocytosis would have had great physiological benefit for a mitochondrion-bearing cell.
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Affiliation(s)
- William F Martin
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Aloysius G M Tielens
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marek Mentel
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Sriram G Garg
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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155
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Dombrowski N, Seitz KW, Teske AP, Baker BJ. Genomic insights into potential interdependencies in microbial hydrocarbon and nutrient cycling in hydrothermal sediments. MICROBIOME 2017; 5:106. [PMID: 28835260 PMCID: PMC5569505 DOI: 10.1186/s40168-017-0322-2] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/01/2017] [Indexed: 05/10/2023]
Abstract
BACKGROUND Deep-sea hydrothermal vents are hotspots for productivity and biodiversity. Thermal pyrolysis and circulation produce fluids rich in hydrocarbons and reduced compounds that stimulate microbial activity in surrounding sediments. Several studies have characterized the diversity of Guaymas Basin (Gulf of California) sediment-inhabiting microorganisms; however, many of the identified taxa lack cultures or genomic representations. Here, we resolved the metabolic potential and community-level interactions of these diverse communities by reconstructing and analyzing microbial genomes from metagenomic sequencing data. RESULTS We reconstructed 115 microbial metagenome-assembled genomes comprising 27 distinct archaeal and bacterial phyla. The archaea included members of the DPANN and TACK superphyla, Bathyarchaeota, novel Methanosarcinales (GoM-Arc1), and anaerobic methane-oxidizing lineages (ANME-1). Among the bacterial phyla, members of the Bacteroidetes, Chloroflexi, and Deltaproteobacteria were metabolically versatile and harbored potential pathways for hydrocarbon and lipid degradation and a variety of respiratory processes. Genes encoding enzymes that activate anaerobic hydrocarbons for degradation were detected in Bacteroidetes, Chloroflexi, Latescibacteria, and KSB1 phyla, while the reconstructed genomes for most candidate bacteria phyla (Aminicenantes, Atribacteria, Omnitrophica, and Stahlbacteria) indicated a fermentative metabolism. Newly obtained GoM-Arc1 archaeal genomes encoded novel pathways for short-chain hydrocarbon oxidation by alkyl-coenzyme M formation. We propose metabolic linkages among different functional groups, such as fermentative community members sharing substrate-level interdependencies with sulfur- and nitrogen-cycling microbes. CONCLUSIONS Overall, inferring the physiologies of archaea and bacteria from metagenome-assembled genomes in hydrothermal deep-sea sediments has revealed potential mechanisms of carbon cycling in deep-sea sediments. Our results further suggest a network of biogeochemical interdependencies in organic matter utilization, hydrocarbon degradation, and respiratory sulfur cycling among deep-sea-inhabiting microbial communities.
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Affiliation(s)
- Nina Dombrowski
- Department of Marine Science, Marine Science Institute, University of Texas Austin, Port Aransas, TX USA
| | - Kiley W. Seitz
- Department of Marine Science, Marine Science Institute, University of Texas Austin, Port Aransas, TX USA
| | - Andreas P. Teske
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Brett J. Baker
- Department of Marine Science, Marine Science Institute, University of Texas Austin, Port Aransas, TX USA
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156
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Spang A, Caceres EF, Ettema TJG. Genomic exploration of the diversity, ecology, and evolution of the archaeal domain of life. Science 2017; 357:357/6351/eaaf3883. [DOI: 10.1126/science.aaf3883] [Citation(s) in RCA: 196] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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157
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The growing tree of Archaea: new perspectives on their diversity, evolution and ecology. ISME JOURNAL 2017; 11:2407-2425. [PMID: 28777382 DOI: 10.1038/ismej.2017.122] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 04/07/2017] [Accepted: 06/07/2017] [Indexed: 01/19/2023]
Abstract
The Archaea occupy a key position in the Tree of Life, and are a major fraction of microbial diversity. Abundant in soils, ocean sediments and the water column, they have crucial roles in processes mediating global carbon and nutrient fluxes. Moreover, they represent an important component of the human microbiome, where their role in health and disease is still unclear. The development of culture-independent sequencing techniques has provided unprecedented access to genomic data from a large number of so far inaccessible archaeal lineages. This is revolutionizing our view of the diversity and metabolic potential of the Archaea in a wide variety of environments, an important step toward understanding their ecological role. The archaeal tree is being rapidly filled up with new branches constituting phyla, classes and orders, generating novel challenges for high-rank systematics, and providing key information for dissecting the origin of this domain, the evolutionary trajectories that have shaped its current diversity, and its relationships with Bacteria and Eukarya. The present picture is that of a huge diversity of the Archaea, which we are only starting to explore.
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158
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Occurrence and expression of novel methyl-coenzyme M reductase gene (mcrA) variants in hot spring sediments. Sci Rep 2017; 7:7252. [PMID: 28775334 PMCID: PMC5543129 DOI: 10.1038/s41598-017-07354-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/27/2017] [Indexed: 01/26/2023] Open
Abstract
Recent discoveries have shown that the marker gene for anaerobic methane cycling (mcrA) is more widespread in the Archaea than previously thought. However, it remains unclear whether novel mcrA genes associated with the Bathyarchaeota and Verstraetearchaeota are distributed across diverse environments. We examined two geochemically divergent but putatively methanogenic regions of Yellowstone National Park to investigate whether deeply-rooted archaea possess and express novel mcrA genes in situ. Small-subunit (SSU) rRNA gene analyses indicated that Bathyarchaeota were predominant in seven of ten sediment layers, while the Verstraetearchaeota and Euryarchaeota occurred in lower relative abundance. Targeted amplification of novel mcrA genes suggested that diverse taxa contribute to alkane cycling in geothermal environments. Two deeply-branching mcrA clades related to Bathyarchaeota were identified, while highly abundant verstraetearchaeotal mcrA sequences were also recovered. In addition, detection of SSU rRNA and mcrA transcripts from one hot spring suggested that predominant Bathyarchaeota were also active, and that methane cycling genes are expressed by the Euryarchaeota, Verstraetearchaeota, and an unknown lineage basal to the Bathyarchaeota. These findings greatly expand the diversity of the key marker gene for anaerobic alkane cycling and outline the need for greater understanding of the functional capacity and phylogenetic affiliation of novel mcrA variants.
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159
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Wasmund K, Mußmann M, Loy A. The life sulfuric: microbial ecology of sulfur cycling in marine sediments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:323-344. [PMID: 28419734 PMCID: PMC5573963 DOI: 10.1111/1758-2229.12538] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Almost the entire seafloor is covered with sediments that can be more than 10 000 m thick and represent a vast microbial ecosystem that is a major component of Earth's element and energy cycles. Notably, a significant proportion of microbial life in marine sediments can exploit energy conserved during transformations of sulfur compounds among different redox states. Sulfur cycling, which is primarily driven by sulfate reduction, is tightly interwoven with other important element cycles (carbon, nitrogen, iron, manganese) and therefore has profound implications for both cellular- and ecosystem-level processes. Sulfur-transforming microorganisms have evolved diverse genetic, metabolic, and in some cases, peculiar phenotypic features to fill an array of ecological niches in marine sediments. Here, we review recent and selected findings on the microbial guilds that are involved in the transformation of different sulfur compounds in marine sediments and emphasise how these are interlinked and have a major influence on ecology and biogeochemistry in the seafloor. Extraordinary discoveries have increased our knowledge on microbial sulfur cycling, mainly in sulfate-rich surface sediments, yet many questions remain regarding how sulfur redox processes may sustain the deep-subsurface biosphere and the impact of organic sulfur compounds on the marine sulfur cycle.
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Affiliation(s)
- Kenneth Wasmund
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network “Chemistry meets Microbiology”University of ViennaAlthanstrasse 14ViennaA‐1090Austria
- Austrian Polar Research InstituteViennaAustria
| | - Marc Mußmann
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network “Chemistry meets Microbiology”University of ViennaAlthanstrasse 14ViennaA‐1090Austria
| | - Alexander Loy
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network “Chemistry meets Microbiology”University of ViennaAlthanstrasse 14ViennaA‐1090Austria
- Austrian Polar Research InstituteViennaAustria
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160
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Evaluation and optimization of PCR primers for selective and quantitative detection of marine ANME subclusters involved in sulfate-dependent anaerobic methane oxidation. Appl Microbiol Biotechnol 2017; 101:5847-5859. [PMID: 28620686 PMCID: PMC5501906 DOI: 10.1007/s00253-017-8338-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/07/2017] [Accepted: 05/08/2017] [Indexed: 01/08/2023]
Abstract
Since the discovery that anaerobic methanotrophic archaea (ANME) are involved in the anaerobic oxidation of methane coupled to sulfate reduction in marine sediments, different primers and probes specifically targeting the 16S rRNA gene of these archaea have been developed. Microbial investigation of the different ANME subtypes (ANME-1; ANME-2a, b, and c; and ANME-3) was mainly done in sediments where specific subtypes of ANME were highly enriched and methanogenic cell numbers were low. In different sediments with higher archaeal diversity and abundance, it is important that primers and probes targeting different ANME subtypes are very specific and do not detect other ANME subtypes or methanogens that are also present. In this study, primers and probes that were regularly used in AOM studies were tested in silico on coverage and specificity. Most of the previously developed primers and probes were not specific for the ANME subtypes, thereby not reflecting the actual ANME population in complex samples. Selected primers that showed good coverage and high specificity for the subclades ANME-1, ANME-2a/b, and ANME-2c were thoroughly validated using quantitative polymerase chain reaction (qPCR). From these qPCR tests, only certain combinations seemed suitable for selective amplification. After optimization of these primer sets, we obtained valid primer combinations for the selective detection and quantification of ANME-1, ANME-2a/b, and ANME-2c in samples where different ANME subtypes and possibly methanogens could be present. As a result of this work, we propose a standard workflow to facilitate selection of suitable primers for qPCR experiments on novel environmental samples.
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161
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Stagars MH, Mishra S, Treude T, Amann R, Knittel K. Microbial Community Response to Simulated Petroleum Seepage in Caspian Sea Sediments. Front Microbiol 2017; 8:764. [PMID: 28503173 PMCID: PMC5409227 DOI: 10.3389/fmicb.2017.00764] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 04/12/2017] [Indexed: 11/17/2022] Open
Abstract
Anaerobic microbial hydrocarbon degradation is a major biogeochemical process at marine seeps. Here we studied the response of the microbial community to petroleum seepage simulated for 190 days in a sediment core from the Caspian Sea using a sediment-oil-flow-through (SOFT) system. Untreated (without simulated petroleum seepage) and SOFT sediment microbial communities shared 43% bacterial genus-level 16S rRNA-based operational taxonomic units (OTU0.945) but shared only 23% archaeal OTU0.945. The community differed significantly between sediment layers. The detection of fourfold higher deltaproteobacterial cell numbers in SOFT than in untreated sediment at depths characterized by highest sulfate reduction rates and strongest decrease of gaseous and mid-chain alkane concentrations indicated a specific response of hydrocarbon-degrading Deltaproteobacteria. Based on an increase in specific CARD-FISH cell numbers, we suggest the following groups of sulfate-reducing bacteria to be likely responsible for the observed decrease in aliphatic and aromatic hydrocarbon concentration in SOFT sediments: clade SCA1 for propane and butane degradation, clade LCA2 for mid- to long-chain alkane degradation, clade Cyhx for cycloalkanes, pentane and hexane degradation, and relatives of Desulfobacula for toluene degradation. Highest numbers of archaea of the genus Methanosarcina were found in the methanogenic zone of the SOFT core where we detected preferential degradation of long-chain hydrocarbons. Sequencing of masD, a marker gene for alkane degradation encoding (1-methylalkyl)succinate synthase, revealed a low diversity in SOFT sediment with two abundant species-level MasD OTU0.96.
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Affiliation(s)
- Marion H Stagars
- Department of Molecular Ecology, Max Planck Institute for Marine MicrobiologyBremen, Germany
| | - Sonakshi Mishra
- Department of Marine Biogeochemistry, GEOMAR - Helmholtz Centre for Ocean Research KielKiel, Germany
| | - Tina Treude
- Department of Marine Biogeochemistry, GEOMAR - Helmholtz Centre for Ocean Research KielKiel, Germany.,Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, Los AngelesCA, USA.,Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los AngelesCA, USA
| | - Rudolf Amann
- Department of Molecular Ecology, Max Planck Institute for Marine MicrobiologyBremen, Germany
| | - Katrin Knittel
- Department of Molecular Ecology, Max Planck Institute for Marine MicrobiologyBremen, Germany
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162
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Abstract
Anaerobic methane oxidation in archaea is often presented to operate via a pathway of “reverse methanogenesis”. However, if the cumulative reactions of a methanogen are run in reverse there is no apparent way to conserve energy. Recent findings suggest that chemiosmotic coupling enzymes known from their use in methylotrophic and acetoclastic methanogens—in addition to unique terminal reductases—biochemically facilitate energy conservation during complete CH4 oxidation to CO2. The apparent enzyme modularity of these organisms highlights how microbes can arrange their energy metabolisms to accommodate diverse chemical potentials in various ecological niches, even in the extreme case of utilizing “reverse” thermodynamic potentials.
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163
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Ragsdale SW. Microbiology: Deep-sea secrets of butane metabolism. Nature 2016; 539:367-368. [PMID: 27853208 DOI: 10.1038/539367a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Stephen W Ragsdale
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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164
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