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Oren A. Novel insights into the diversity of halophilic microorganisms and their functioning in hypersaline ecosystems. NPJ BIODIVERSITY 2024; 3:18. [PMID: 39242694 PMCID: PMC11332174 DOI: 10.1038/s44185-024-00050-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Accepted: 06/25/2024] [Indexed: 09/09/2024]
Abstract
Our understanding of the microbial diversity inhabiting hypersaline environments, here defined as containing >100-150 g/L salts, has greatly increased in the past five years. Halophiles are found in each of the three domains of life. Many novel types have been cultivated, and metagenomics and other cultivation-independent approaches have revealed the existence of many previously unrecognized lineages. Syntrophic interactions between different phylogenetic lineages have been discovered, such as the symbiosis between members of the archaeal class Halobacteria and the 'Candidatus Nanohalarchaeota'. Metagenomics techniques also have shed light on the biogeography of halophiles, especially of the genera Salinibacter (Bacteria) and Haloquadratum and Halorubrum (Archaea). Exploration of the microbiome of hypersaline lakes led to the discovery of novel types of metabolism previously unknown to occur at high salt concentrations. Studies of environments with high concentrations of chaotropic ions such as magnesium, calcium, and lithium have refined our understanding of the limits of life.
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Affiliation(s)
- Aharon Oren
- Department of Plant and Environmental Sciences, The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel.
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Bhattarai B, Bhattacharjee AS, Coutinho FH, Goel R. Investigating the viral ecology and contribution to the microbial ecology in full-scale mesophilic anaerobic digesters. CHEMOSPHERE 2024; 349:140743. [PMID: 37984648 DOI: 10.1016/j.chemosphere.2023.140743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 11/22/2023]
Abstract
In an attempt to assess the diversity of viruses and their potential to modulate the metabolism of functional microorganisms in anaerobic digesters, we collected digestate from three mesophilic anaerobic digesters in full-scale wastewater treatment plants treating real municipal wastewater. The reads were analyzed using bioinformatics algorithms to elucidate viral diversity, identify their potential role in modulating the metabolism of functional microorganisms, and provide essential genomic information for the potential use of virus-mediated treatment in controlling the anaerobic digester microbiome. We found that Siphoviridae was the dominant family in mesophilic anaerobic digesters, followed by Myoviridae and Podoviridae. Lysogeny was prevalent in mesophilic anaerobic digesters as the majority of metagenome-assembled genomes contained at least one viral genome within them. One virus within the genome of an acetoclastic methanogen (Methanothrix soehngenii) was observed with a gene (fwdE) acquired via lateral transfer from hydrogenotrophic methanogens. The virus-mediated acquisition of fwdE gene enables possibility of mixotrophic methanogenesis in Methanothrix soehngenii. This evidence highlighted that lysogeny provides fitness advantage to methanogens in anaerobic digesters by adding flexibility to changing substrates. Similarly, we found auxiliary metabolic genes, such as cellulase and alpha glucosidase, of bacterial origin responsible for sludge hydrolysis in viruses. Additionally, we discovered novel viral genomes and provided genomic information on viruses infecting acidogenic, acetogenic, and pathogenic bacteria that can potentially be used for virus-mediated treatment to deal with the souring problem in anaerobic digesters and remove pathogens from biosolids before land application. Collectively, our study provides a genome-level understanding of virome in conjunction with the microbiome in anaerobic digesters that can be used to optimize the anaerobic digestion process for efficient biogas generation.
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Affiliation(s)
- Bishav Bhattarai
- The University of Utah, Department of Civil and Environmental Engineering, 110 S Central Campus Drive, Salt Lake City, UT, 84112, United States.
| | - Ananda Shankar Bhattacharjee
- Department of Environmental Sciences, The University of California, Riverside, Riverside, CA, United States; USDA-ARS, United States Salinity Laboratory, Riverside, CA, United States
| | - Felipe H Coutinho
- Department of Marine Biology and Oceanography, Institute of Marine Sciences, Consejo Superior de Investigaciones Científicas (ICM-CISC), Barcelona, Spain
| | - Ramesh Goel
- The University of Utah, Department of Civil and Environmental Engineering, 110 S Central Campus Drive, Salt Lake City, UT, 84112, United States.
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Sun K, Yu M, Zhu XY, Xue CX, Zhang Y, Chen X, Yao P, Chen L, Fu L, Yang Z, Zhang XH. Microbial communities related to the sulfur cycle in the Sansha Yongle Blue Hole. Microbiol Spectr 2023; 11:e0114923. [PMID: 37623326 PMCID: PMC10580873 DOI: 10.1128/spectrum.01149-23] [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: 03/16/2023] [Accepted: 07/13/2023] [Indexed: 08/26/2023] Open
Abstract
The Sansha Yongle Blue Hole (SYBH), the deepest blue hole in the world, is an excellent habitat for revealing biogeochemical cycles in the anaerobic environment. However, how sulfur cycling is mediated by microorganisms in the SYBH hasn't been fully understood. In this study, the water layers of the SYBH were divided into oxic zone, hypoxic zone, anoxic zone I and II, and microbial-mediated sulfur cycling in the SYBH was comprehensively interpreted. The 16S rRNA genes/transcripts analyses showed that the microbial community structures associated with the sulfur cycling in each zone had distinctive features. Sulfur-oxidizing bacteria were mostly constituted by Gammaproteobacteria, Alphaproteobacteria, Campylobacterota, and Chlorobia above the anoxic zone I and sulfate-reducing bacteria were dominated by Desulfobacterota in anoxic zones. Metagenomic analyses showed that the sulfide-oxidation-related gene sqr and genes encoding the Sox system were mainly distributed in the anoxic zone I, while genes related to dissimilatory sulfate reduction and sulfur intermediate metabolite reduction were mainly distributed in the anoxic zone II, indicating different sulfur metabolic processes between these two zones. Moreover, sulfur-metabolism-related genes were identified in 81 metagenome-assembled genomes (MAGs), indicating a high diversity of microbial communities involved in sulfur cycling. Among them, three MAGs from the candidate phyla JdFR-76 and AABM5-125-24 with genes related to dissimilatory sulfate reduction exhibited distinctive metabolic features. Our results showed unique and novel microbial populations in the SYBH sulfur cycle correlated to the sharp redox gradients, revealing complex biogeochemical processes in this extreme environment. IMPORTANCE Oxygen-deficient regions in the global ocean are expanding rapidly and affect the growth, reproduction and ecological processes of marine organisms. The anaerobic water body of about 150 m in the Sansha Yongle Blue Hole (SYBH) provided a suitable environment to study the specific microbial metabolism in anaerobic seawater. Here, we found that the vertical distributions of the total and active communities of sulfur-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB) were different in each water layer of the SYBH according to the dissolved oxygen content. Genes related to sulfur metabolism also showed distinct stratification characteristics. Furthermore, we have obtained diverse metagenome-assembled genomes, some of which exhibit special sulfur metabolic characteristics, especially candidate phyla JdFR-76 and AABM5-125-24 were identified as potential novel SRB. The results of this study will promote further understanding of the sulfur cycle in extreme environments, as well as the environmental adaptability of microorganisms in blue holes.
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Affiliation(s)
- Kai Sun
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Min Yu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiao-Yu Zhu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Chun-Xu Xue
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yunhui Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xing Chen
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Peng Yao
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China
| | - Lin Chen
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China
| | - Liang Fu
- Sansha Track Ocean Coral Reef Conservation Research Institute, Sansha, China
| | - Zuosheng Yang
- College of Marine Geosciences, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
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Gagnon JC, Beauregard-Tousignant S, Marcil JS, Lazar CS. Deep Isolated Aquifer Brines Harbor Atypical Halophilic Microbial Communities in Quebec, Canada. Genes (Basel) 2023; 14:1529. [PMID: 37628582 PMCID: PMC10454208 DOI: 10.3390/genes14081529] [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: 06/15/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023] Open
Abstract
The deep terrestrial subsurface, hundreds of meters to kilometers below the surface, is characterized by oligotrophic conditions, dark and often anoxic settings, with fluctuating pH, salinity, and water availability. Despite this, microbial populations are detected and active, contributing to biogeochemical cycles over geological time. Because it is extremely difficult to access the deep biosphere, little is known about the identity and metabolisms of these communities, although they likely possess unknown pathways and might interfere with deep waste deposits. Therefore, we analyzed rock and groundwater microbial communities from deep, isolated brine aquifers in two regions dating back to the Ordovician and Devonian, using amplicon and whole genome sequencing. We observed significant differences in diversity and community structure between both regions, suggesting an impact of site age and composition. The deep hypersaline groundwater did not contain typical halophilic bacteria, and genomes suggested pathways involved in protein and hydrocarbon degradation, and carbon fixation. We identified mainly one strategy to cope with osmotic stress: compatible solute uptake and biosynthesis. Finally, we detected many bacteriophage families, potentially indicating that bacteria are infected. However, we also found auxiliary metabolic genes in the viral genomes, probably conferring an advantage to the infected hosts.
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Affiliation(s)
- Jean-Christophe Gagnon
- Department of Biological Sciences, University of Québec at Montréal (UQAM), C.P. 8888, Succ. Centre-Ville, Montréal, QC H3C 3P8, Canada; (J.-C.G.); (S.B.-T.)
- Interuniversity Research Group in Limnology/Groupe de Recherche Interuniversitaire en Limnologie (GRIL), Montréal, QC H3C 3P8, Canada
| | - Samuel Beauregard-Tousignant
- Department of Biological Sciences, University of Québec at Montréal (UQAM), C.P. 8888, Succ. Centre-Ville, Montréal, QC H3C 3P8, Canada; (J.-C.G.); (S.B.-T.)
| | - Jean-Sébastien Marcil
- Derena Geosciences, Quebec, QC G7A 3Y5, Canada;
- Ressources Utica Inc., Quebec, QC G1V 4M7, Canada
| | - Cassandre Sara Lazar
- Department of Biological Sciences, University of Québec at Montréal (UQAM), C.P. 8888, Succ. Centre-Ville, Montréal, QC H3C 3P8, Canada; (J.-C.G.); (S.B.-T.)
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Abstract
Common culturing techniques and priorities bias our discovery towards specific traits that may not be representative of microbial diversity in nature. So far, these biases have not been systematically examined. To address this gap, here we use 116,884 publicly available metagenome-assembled genomes (MAGs, completeness ≥80%) from 203 surveys worldwide as a culture-independent sample of bacterial and archaeal diversity, and compare these MAGs to the popular RefSeq genome database, which heavily relies on cultures. We compare the distribution of 12,454 KEGG gene orthologs (used as trait proxies) in the MAGs and RefSeq genomes, while controlling for environment type (ocean, soil, lake, bioreactor, human, and other animals). Using statistical modeling, we then determine the conditional probabilities that a species is represented in RefSeq depending on its genetic repertoire. We find that the majority of examined genes are significantly biased for or against in RefSeq. Our systematic estimates of gene prevalences across bacteria and archaea in nature and gene-specific biases in reference genomes constitutes a resource for addressing these issues in the future.
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Affiliation(s)
- Sage Albright
- Department of Biology, University of Oregon, Eugene, USA
| | - Stilianos Louca
- Department of Biology, University of Oregon, Eugene, USA.
- Institute of Ecology and Evolution, University of Oregon, Eugene, USA.
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Coskun ÖK, Gomez-Saez GV, Beren M, Ozcan D, Hosgormez H, Einsiedl F, Orsi WD. Carbon metabolism and biogeography of candidate phylum " Candidatus Bipolaricaulota" in geothermal environments of Biga Peninsula, Turkey. Front Microbiol 2023; 14:1063139. [PMID: 36910224 PMCID: PMC9992828 DOI: 10.3389/fmicb.2023.1063139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 01/17/2023] [Indexed: 02/25/2023] Open
Abstract
Terrestrial hydrothermal springs and aquifers are excellent sites to study microbial biogeography because of their high physicochemical heterogeneity across relatively limited geographic regions. In this study, we performed 16S rRNA gene sequencing and metagenomic analyses of the microbial diversity of 11 different geothermal aquifers and springs across the tectonically active Biga Peninsula (Turkey). Across geothermal settings ranging in temperature from 43 to 79°C, one of the most highly represented groups in both 16S rRNA gene and metagenomic datasets was affiliated with the uncultivated phylum "Candidatus Bipolaricaulota" (former "Ca. Acetothermia" and OP1 division). The highest relative abundance of "Ca. Bipolaricaulota" was observed in a 68°C geothermal brine sediment, where it dominated the microbial community, representing 91% of all detectable 16S rRNA genes. Correlation analysis of "Ca. Bipolaricaulota" operational taxonomic units (OTUs) with physicochemical parameters indicated that salinity was the strongest environmental factor measured associated with the distribution of this novel group in geothermal fluids. Correspondingly, analysis of 23 metagenome-assembled genomes (MAGs) revealed two distinct groups of "Ca. Bipolaricaulota" MAGs based on the differences in carbon metabolism: one group encoding the bacterial Wood-Ljungdahl pathway (WLP) for H2 dependent CO2 fixation is selected for at lower salinities, and a second heterotrophic clade that lacks the WLP that was selected for under hypersaline conditions in the geothermal brine sediment. In conclusion, our results highlight that the biogeography of "Ca. Bipolaricaulota" taxa is strongly correlated with salinity in hydrothermal ecosystems, which coincides with key differences in carbon acquisition strategies. The exceptionally high relative abundance of apparently heterotrophic representatives of this novel candidate Phylum in geothermal brine sediment observed here may help to guide future enrichment experiments to obtain representatives in pure culture.
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Affiliation(s)
- Ömer K Coskun
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Gonzalo V Gomez-Saez
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,GeoBio-CenterLMU, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Murat Beren
- Department of Geological Engineering, Istanbul University-Cerrahpasa, Istanbul, Türkiye
| | - Dogacan Ozcan
- Department of Geological Engineering, Istanbul University-Cerrahpasa, Istanbul, Türkiye
| | - Hakan Hosgormez
- Department of Geological Engineering, Istanbul University-Cerrahpasa, Istanbul, Türkiye
| | - Florian Einsiedl
- Chair of Hydrogeology, TUM School of Engineering and Design, Technical University of Munich, Munich, Germany
| | - William D Orsi
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,GeoBio-CenterLMU, Ludwig-Maximilians-Universität München, Munich, Germany
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Busse L, Tisza M, DiRuggiero J. Viruses Ubiquity and Diversity in Atacama Desert Endolithic Communities. Viruses 2022; 14:1983. [PMID: 36146789 PMCID: PMC9500819 DOI: 10.3390/v14091983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
Viruses are key players in the environment, and recent metagenomic studies have revealed their diversity and genetic complexity. Despite progress in understanding the ecology of viruses in extreme environments, viruses' dynamics and functional roles in dryland ecosystems, which cover about 45% of the Earth's land surfaces, remain largely unexplored. This study characterizes virus sequences in the metagenomes of endolithic (within rock) microbial communities ubiquitously found in hyper-arid deserts. Taxonomic classification and network construction revealed the presence of novel and diverse viruses in communities inhabiting calcite, gypsum, and ignimbrite rocks. Viral genome maps show a high level of protein diversity within and across endolithic communities and the presence of virus-encoded auxiliary metabolic genes. Phage-host relationships were predicted by matching tRNA, CRISPR spacer, and protein sequences in the viral and microbial metagenomes. Primary producers and heterotrophic bacteria were found to be putative hosts to some viruses. Intriguingly, viral diversity was not correlated with microbial diversity across rock substrates.
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Affiliation(s)
- Leora Busse
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Mike Tisza
- The Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jocelyne DiRuggiero
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
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