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Richter M, Sattler C, Schöne C, Rother M. Pyruvate-dependent growth of Methanosarcina acetivorans. J Bacteriol 2024; 206:e0036323. [PMID: 38305193 PMCID: PMC10882976 DOI: 10.1128/jb.00363-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/11/2024] [Indexed: 02/03/2024] Open
Abstract
Methanogenesis is a key step during anaerobic biomass degradation. Methanogenic archaea (methanogens) are the only organisms coupling methanogenic substrate conversion to energy conservation. The range of substrates utilized by methanogens is limited, with acetate and H2+CO2 being the ecologically most relevant. The only single methanogenic energy substrate containing more carbon-carbon bonds than acetate is pyruvate. Only the aggregate-forming, freshwater methanogen Methanosarcina barkeri Fusaro was shown to grow on this compound. Here, the pyruvate-utilizing capabilities of the single-celled, marine Methanosarcina acetivorans were addressed. Robust pyruvate-dependent, methanogenic, growth could be established by omitting CO2 from the growth medium. Growth rates which were independent of the pyruvate concentration indicated that M. acetivorans actively translocates pyruvate across the cytoplasmic membrane. When 2-bromoethanesulfonate (BES) inhibited methanogenesis to more than 99%, pyruvate-dependent growth was acetogenic and sustained. However, when methanogenesis was completely inhibited M. acetivorans did not grow on pyruvate. Analysis of metabolites showed that acetogenesis is used by BES-inhibited M. acetivorans as a sink for electrons derived from pyruvate oxidation and that other, thus far unidentified, metabolites are produced.IMPORTANCEThe known range of methanogenic growth substrates is very limited and M. acetivorans is only the second methanogenic species for which growth on pyruvate is demonstrated. Besides some commonalities, analysis of M. acetivorans highlights differences in pyruvate metabolism among Methanosarcina species. The observation that M. acetivorans probably imports pyruvate actively indicates that the capabilities for heterotrophic catabolism in methanogens may be underestimated. The mostly acetogenic growth of M. acetivorans on pyruvate with concomitant inhibition of methanogenesis confirms that energy conservation of methanogenic archaea can be independent of methane formation.
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Affiliation(s)
- Marcus Richter
- Fakultät Biologie, Technische Universität Dresden, Dresden, Germany
| | | | - Christian Schöne
- Fakultät Biologie, Technische Universität Dresden, Dresden, Germany
| | - Michael Rother
- Fakultät Biologie, Technische Universität Dresden, Dresden, Germany
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Durán-Viseras A, Sánchez-Porro C, Viver T, Konstantinidis KT, Ventosa A. Discovery of the Streamlined Haloarchaeon Halorutilus salinus, Comprising a New Order Widespread in Hypersaline Environments across the World. mSystems 2023; 8:e0119822. [PMID: 36943059 PMCID: PMC10134839 DOI: 10.1128/msystems.01198-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
The class Halobacteria is one of the most diverse groups within the Euryarchaeota phylum, whose members are ubiquitously distributed in hypersaline environments, where they often constitute the major population. Here, we report the discovery and isolation of a new halophilic archaeon, strain F3-133T exhibiting ≤86.3% 16S rRNA gene identity to any previously cultivated archaeon, and, thus, representing a new order. Analysis of available 16S rRNA gene amplicon and metagenomic data sets showed that the new isolate represents an abundant group in intermediate-to-high salinity ecosystems and is widely distributed across the world. The isolate presents a streamlined genome, which probably accounts for its ecological success in nature and its fastidious growth in culture. The predominant osmoprotection mechanism appears to be the typical salt-in strategy used by other haloarchaea. Furthermore, the genome contains the complete gene set for nucleotide monophosphate degradation pathway through archaeal RuBisCO, being within the first halophilic archaea representatives reported to code this enzyme. Genomic comparisons with previously described representatives of the phylum Euryarchaeota were consistent with the 16S rRNA gene data in supporting that our isolate represents a novel order within the class Halobacteria for which we propose the names Halorutilales ord. nov., Halorutilaceae fam. nov., Halorutilus gen. nov. and Halorutilus salinus sp. nov. IMPORTANCE The discovery of the new halophilic archaeon, Halorutilus salinus, representing a novel order, family, genus, and species within the class Halobacteria and phylum Euryarchaeota clearly enables insights into the microbial dark matter, expanding the current taxonomical knowledge of this group of archaea. The in-depth comparative genomic analysis performed on this new taxon revealed one of the first known examples of an Halobacteria representative coding the archaeal RuBisCO gene and with a streamlined genome, being ecologically successful in nature and explaining its previous non-isolation. Altogether, this research brings light into the understanding of the physiology of the Halobacteria class members, their ecological distribution, and capacity to thrive in hypersaline environments.
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Affiliation(s)
- Ana Durán-Viseras
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, Spain
- School of Civil & Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Cristina Sánchez-Porro
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, Spain
| | - Tomeu Viver
- Marine Microbiology Group, Department of Animal and Microbial Biodiversity, Mediterranean Institute for Advanced Studies (IMEDEA, CSIC-UIB), Esporles, Spain
| | | | - Antonio Ventosa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, Spain
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3
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Zhao J, Shakir Y, Deng Y, Zhang Y. Use of modified ichip for the cultivation of thermo-tolerant microorganisms from the hot spring. BMC Microbiol 2023; 23:56. [PMID: 36869305 PMCID: PMC9983152 DOI: 10.1186/s12866-023-02803-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/20/2023] [Indexed: 03/05/2023] Open
Abstract
BACKGROUND Thermostable microorganisms are extremophiles. They have a special genetic background and metabolic pathway and can produce a variety of enzymes and other active substances with special functions. Most thermo-tolerant microorganisms from environmental samples have resisted cultivation on artificial growth media. Therefore, it is of great significance to isolate more thermo-tolerant microorganisms and study their characteristics to explore the origin of life and exploit more thermo-tolerant enzymes. Tengchong hot spring in Yunnan contains a lot of thermo-tolerant microbial resources because of its perennial high temperature. The ichip method was developed by D. Nichols in 2010 and can be used to isolate so-called "uncultivable" microorganisms from different environments. Here, we describe the first application of modified ichip to isolate thermo-tolerant bacteria from hot springs. RESULTS In this study, 133 strains of bacteria belonging to 19 genera were obtained. 107 strains of bacteria in 17 genera were isolated by modified ichip, and 26 strains of bacteria in 6 genera were isolated by direct plating methods. 25 strains are previously uncultured, 20 of which can only be cultivated after being domesticated by ichip. Two strains of previously unculturable Lysobacter sp., which can withstand 85 °C, were isolated for the first time. Alkalihalobacillus, Lysobacter and Agromyces genera were first found to have 85 °C tolerance. CONCLUSION Our results indicate that the modified ichip approach can be successfully applied in a hot spring environment.
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Affiliation(s)
- Juntian Zhao
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Yasmeen Shakir
- Department of Biochemistry, Hazara University, Mansehra, Pakistan
| | - Yulin Deng
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Ying Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
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Comparative Genomic Insights into the Evolution of Halobacteria-Associated " Candidatus Nanohaloarchaeota". mSystems 2022; 7:e0066922. [PMID: 36259734 PMCID: PMC9765267 DOI: 10.1128/msystems.00669-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Members of the phylum "Candidatus Nanohaloarchaeota," a representative lineage within the DPANN superphylum, are characterized by their nanosized cells and symbiotic lifestyle with Halobacteria. However, the development of the symbiosis remains unclear. Here, we propose two novel families, "Candidatus Nanoanaerosalinaceae" and "Candidatus Nanohalalkaliarchaeaceae" in "Ca. Nanohaloarchaeota," represented by five dereplicated metagenome-assembled genomes obtained from hypersaline sediments or related enrichment cultures of soda-saline lakes. Phylogenetic analyses reveal that the two novel families are placed at the root of the family "Candidatus Nanosalinaceae," including the cultivated taxa. The two novel families prefer hypersaline sediments, and the acid shift of predicted proteomes indicates a "salt-in" strategy for hypersaline adaptation. They contain a lower proportion of putative horizontal gene transfers from Halobacteria than "Ca. Nanosalinaceae," suggesting a weaker association with Halobacteria. Functional prediction and historical events reconstruction disclose that they exhibit divergent potentials in carbohydrate and organic acid metabolism and environmental responses. Globally, comparative genomic analyses based on the new families enrich the taxonomic and functional diversity of "Ca. Nanohaloarchaeota" and provide insights into the evolutionary process of "Ca. Nanohaloarchaeota" and their symbiotic relationship with Halobacteria. IMPORTANCE The DPANN superphylum is a group of archaea widely distributed in various habitats. They generally have small cells and have a symbiotic lifestyle with other archaea. The archaeal symbiotic interaction is vital to understanding microbial communities. However, the formation and evolution of the symbiosis between the DPANN lineages and other diverse archaea remain unclear. Based on phylogeny, habitat distribution, hypersaline adaptation, host prediction, functional potentials, and historical events of "Ca. Nanohaloarchaeota," a representative phylum within the DPANN superphylum, we report two novel families representing intermediate stages, and we infer the evolutionary process of "Ca. Nanohaloarchaeota" and their Halobacteria-associated symbiosis. Altogether, this research helps in understanding the evolution of symbiosis in "Ca. Nanohaloarchaeota" and provides a model for the evolution of other DPANN lineages.
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Genomic analysis of a novel species Halomonas shambharensis isolated from hypersaline lake in Northwest India. Mol Biol Rep 2021; 48:1045-1053. [PMID: 33479827 DOI: 10.1007/s11033-020-06131-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/24/2020] [Indexed: 10/22/2022]
Abstract
Genome analysis of Halomonas shambharensis, a novel species, was performed to understand the osmoprotectant strategies used by the strain to overcome the salinity stress and to explore the prospective industrial uses. It will also help to better understand the ecological roles of Halomonas species in hypersaline habitats. Ultrastructure of the cell was determined by using transmission electron microscopy. Standard microbiological methods were used to find out growth parameters and heterotrophic mode of nutrition. For Genome analysis, complete bacterial genome sequencing was performed using the Oxford Nanopore MinION DNA Sequencer. Assembly, annotation and finishing of the obtained sequence were done by using a Prokaryotic Genome Annotation Pipeline (PGAP) (SPAdes v. 3.10.1). Predicted Coading sequences (CDSs) obtained through the PGAP were used for functional annotation using Clusters of Orthologous Groups and Kyoto Encyclopedia of Genes and Genomes (KEGG) platforms. The H. shambharensis was found to be a Gram-stain-negative, rod-shaped bacterium, motile with a peritrichous flagella. The H. shambharensis bacterium can grow in a wide range of temperature (from 25 to 65 °C), pH (pH 4 to pH 12.0) and salt concentration (5.0% NaCl to 30.0% NaCl). After annotation and assembly, the total genome size obtained was 1,533,947 bp, which revealed 146 subsystems, 3847 coding sequences, and 19RNAs with G+C content of 63.6%. Gene annotation identified the genes related to various metabolic pathways, including carbohydrate metabolism, fatty acid metabolism and stress tolerance. The genomic dataset of H. shambharensis will be useful for analysis of protein-coding gene families and how these coding genes are significant for the survival and metabolism among the different species of Halomonas. The complete genome sequence presented here will help to unravel the biotechnological potential of H. shambharensis for production of the high-value products such as betaine, or as a source of gene-mining for individual enzymes.
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Depthwise microbiome and isotopic profiling of a moderately saline microbial mat in a solar saltern. Sci Rep 2020; 10:20686. [PMID: 33244085 PMCID: PMC7693307 DOI: 10.1038/s41598-020-77622-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 11/09/2020] [Indexed: 11/23/2022] Open
Abstract
The solar salterns in Tuticorin, India, are man-made, saline to hypersaline systems hosting some uniquely adapted populations of microorganisms and eukaryotic algae that have not been fully characterized. Two visually different microbial mats (termed ‘white’ and ‘green’) developing on the reservoir ponds (53 PSU) were isolated from the salterns. Firstly, archaeal and bacterial diversity in different vertical layers of the mats were analyzed. Culture-independent 16S rRNA gene analysis revealed that both bacteria and archaea were rich in their diversity. The top layers had a higher representation of halophilic archaea Halobacteriaceae, phylum Chloroflexi, and classes Anaerolineae, Delta- and Gamma- Proteobacteria than the deeper sections, indicating that a salinity gradient exists within the mats. Limited presence of Cyanobacteria and detection of algae-associated bacteria, such as Phycisphaerae, Phaeodactylibacter and Oceanicaulis likely implied that eukaryotic algae and other phototrophs could be the primary producers within the mat ecosystem. Secondly, predictive metabolic pathway analysis using the 16S rRNA gene data revealed that in addition to the regulatory microbial functions, methane and nitrogen metabolisms were prevalent. Finally, stable carbon and nitrogen isotopic compositions determined from both mat samples showed that the δ13Corg and δ15Norg values increased slightly with depth, ranging from − 16.42 to − 14.73‰, and 11.17 to 13.55‰, respectively. The isotopic signature along the microbial mat profile followed a pattern that is distinctive to the community composition and net metabolic activities, and comparable to saline mats in other salterns. The results and discussions presented here by merging culture-independent studies, predictive metabolic analyses and isotopic characterization, provide a collective strategy to understand the compositional and functional characteristics of microbial mats in saline environments.
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Metabolic Diversity and Evolutionary History of the Archaeal Phylum " Candidatus Micrarchaeota" Uncovered from a Freshwater Lake Metagenome. Appl Environ Microbiol 2020; 86:AEM.02199-20. [PMID: 32978130 DOI: 10.1128/aem.02199-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 09/18/2020] [Indexed: 12/19/2022] Open
Abstract
Acidophilic archaea of the archaeal Richmond Mine acidophilic nanoorganisms (ARMAN) group from the uncultured candidate phylum "Candidatus Micrarchaeota" have small genomes and cell sizes and are known to be metabolically dependent and physically associated with their Thermoplasmatales hosts. However, phylogenetically diverse "Ca Micrarchaeota" are widely distributed in various nonacidic environments, and it remains uncertain because of the lack of complete genomes whether they are also devoted to a partner-dependent lifestyle. Here, we obtained nine metagenome-assembled genomes of "Ca Micrarchaeota" from the sediments of a meromictic freshwater lake, including a complete, closed 1.2 Mbp genome of "Ca Micrarchaeota" Sv326, an archaeon phylogenetically distant from the ARMAN lineage. Genome analysis revealed that, contrary to ARMAN "Ca Micrarchaeota," the Sv326 archaeon has complete glycolytic pathways and ATP generation mechanisms in substrate phosphorylation reactions, the capacities to utilize some sugars and amino acids as substrates, and pathways for de novo nucleotide biosynthesis but lacked an aerobic respiratory chain. We suppose that Sv326 is a free-living scavenger rather than an obligate parasite/symbiont. Comparative analysis of "Ca Micrarchaeota" genomes representing different order-level divisions indicated that evolution of the "Ca Micrarchaeota" from a free-living "Candidatus Diapherotrites"-like ancestor involved losses of important metabolic pathways in different lineages and gains of specific functions in the course of adaptation to a partner-dependent lifestyle and specific environmental conditions. The ARMAN group represents the most pronounced case of genome reduction and gene loss, while the Sv326 lineage appeared to be rather close to the ancestral state of the "Ca Micrarchaeota" in terms of metabolic potential.IMPORTANCE The recently described superphylum DPANN includes several phyla of uncultivated archaea with small cell sizes, reduced genomes, and limited metabolic capabilities. One of these phyla, "Ca Micrarchaeota," comprises an enigmatic group of archaea found in acid mine drainage environments, the archaeal Richmond Mine acidophilic nanoorganisms (ARMAN) group. Analysis of their reduced genomes revealed the absence of key metabolic pathways consistent with their partner-associated lifestyle, and physical associations of ARMAN cells with their hosts were documented. However, "Ca Micrarchaeota" include several lineages besides the ARMAN group found in nonacidic environments, and none of them have been characterized. Here, we report a complete genome of "Ca Micrarchaeota" from a non-ARMAN lineage. Analysis of this genome revealed the presence of metabolic capacities lost in ARMAN genomes that could enable a free-living lifestyle. These results expand our understanding of genetic diversity, lifestyle, and evolution of "Ca Micrarchaeota."
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8
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Abstract
The brines of natural salt lakes with total salt concentrations exceeding 30% are often colored red by dense communities of halophilic microorganisms. Such red brines are found in the north arm of Great Salt Lake, Utah, in the alkaline hypersaline lakes of the African Rift Valley, and in the crystallizer ponds of coastal and inland salterns where salt is produced by evaporation of seawater or some other source of saline water. Red blooms were also reported in the Dead Sea in the past. Different types of pigmented microorganisms may contribute to the coloration of the brines. The most important are the halophilic archaea of the class Halobacteria that contain bacterioruberin carotenoids as well as bacteriorhodopsin and other retinal pigments, β-carotene-rich species of the unicellular green algal genus Dunaliella and bacteria of the genus Salinibacter (class Rhodothermia) that contain the carotenoid salinixanthin and the retinal protein xanthorhodopsin. Densities of prokaryotes in red brines often exceed 2-3×107 cells/mL. I here review the information on the biota of the red brines, the interactions between the organisms present, as well as the possible roles of the red halophilic microorganisms in the salt production process and some applied aspects of carotenoids and retinal proteins produced by the different types of halophiles inhabiting the red brines.
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Affiliation(s)
- Aharon Oren
- The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
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Dombrowski N, Williams TA, Sun J, Woodcroft BJ, Lee JH, Minh BQ, Rinke C, Spang A. Undinarchaeota illuminate DPANN phylogeny and the impact of gene transfer on archaeal evolution. Nat Commun 2020; 11:3939. [PMID: 32770105 PMCID: PMC7414124 DOI: 10.1038/s41467-020-17408-w] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/25/2020] [Indexed: 01/08/2023] Open
Abstract
The recently discovered DPANN archaea are a potentially deep-branching, monophyletic radiation of organisms with small cells and genomes. However, the monophyly and early emergence of the various DPANN clades and their role in life's evolution are debated. Here, we reconstructed and analysed genomes of an uncharacterized archaeal phylum (Candidatus Undinarchaeota), revealing that its members have small genomes and, while potentially being able to conserve energy through fermentation, likely depend on partner organisms for the acquisition of certain metabolites. Our phylogenomic analyses robustly place Undinarchaeota as an independent lineage between two highly supported 'DPANN' clans. Further, our analyses suggest that DPANN have exchanged core genes with their hosts, adding to the difficulty of placing DPANN in the tree of life. This pattern can be sufficiently dominant to allow identifying known symbiont-host clades based on routes of gene transfer. Together, our work provides insights into the origins and evolution of DPANN and their hosts.
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Affiliation(s)
- Nina Dombrowski
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, P.O. Box 59, NL-1790 AB, Den Burg, The Netherlands
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Jiarui Sun
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Benjamin J Woodcroft
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jun-Hoe Lee
- Department of Cell- and Molecular Biology, Science for Life Laboratory, Uppsala University, SE-75123, Uppsala, Sweden
| | - Bui Quang Minh
- Research School of Computer Science and Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Christian Rinke
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Anja Spang
- NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, P.O. Box 59, NL-1790 AB, Den Burg, The Netherlands.
- Department of Cell- and Molecular Biology, Science for Life Laboratory, Uppsala University, SE-75123, Uppsala, Sweden.
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Zhao D, Zhang S, Xue Q, Chen J, Zhou J, Cheng F, Li M, Zhu Y, Yu H, Hu S, Zheng Y, Liu S, Xiang H. Abundant Taxa and Favorable Pathways in the Microbiome of Soda-Saline Lakes in Inner Mongolia. Front Microbiol 2020; 11:1740. [PMID: 32793172 PMCID: PMC7393216 DOI: 10.3389/fmicb.2020.01740] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 07/03/2020] [Indexed: 12/14/2022] Open
Abstract
Soda-saline lakes are a special type of alkaline lake in which the chloride concentration is greater than the carbonate/bicarbonate concentration. Due to the high pH and a usually higher osmotic pressure than that of a normal soda lake, the microbes may need more energy to thrive in such a double-extreme environment. In this study, we systematically investigated the microbiome of the brine and sediment samples of nine artificially separated ponds (salinities from 5.5% to saturation) within two soda-saline lakes in Inner Mongolia of China, assisted by deep metagenomic sequencing. The main inorganic ions shaped the microbial community in both the brines and sediments, and the chloride concentration exhibited the most significant effect. A total of 385 metagenome-assembled genomes (MAGs) were generated, in which 38 MAGs were revealed as the abundant species in at least one of the eighteen different samples. Interestingly, these abundant species also represented the most branches of the microbiome of the soda-saline lakes at the phylum level. These abundant taxa were close relatives of microorganisms from classic soda lakes and neutral saline environments, but forming a combination of both habitats. Notably, approximately half of the abundant MAGs had the potential to drive dissimilatory sulfur cycling. These MAGs included four autotrophic Ectothiorhodospiraceae MAGs, one Cyanobacteria MAG and nine heterotrophic MAGs with the potential to oxidize sulfur, as well as four abundant MAGs containing genes for elemental sulfur respiration. The possible reason is that reductive sulfur compounds could provide additional energy for the related species, and reductions of oxidative sulfur compounds are more prone to occur under alkaline conditions which support the sulfur cycling. In addition, a unique 1,4-alpha-glucan phosphorylation pathway, but not a normal hydrolysis one, was found in the abundant Candidatus Nanohaloarchaeota MAG NHA-1, which would produce more energy in polysaccharide degradation. In summary, this work has revealed the abundant taxa and favorable pathways in the soda-saline lakes, indicating that efficient energy regeneration pathway may increase the capacity for environmental adaptation in such saline-alkaline environments. These findings may help to elucidate the relationship between microbial metabolism and adaptation to extreme environments.
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Affiliation(s)
- Dahe Zhao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Shengjie Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Qiong Xue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Junyu Chen
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jian Zhou
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Feiyue Cheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Ming Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yaxin Zhu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Haiying Yu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Songnian Hu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yanning Zheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Shuangjiang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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Sucrose Metabolism in Haloarchaea: Reassessment Using Genomics, Proteomics, and Metagenomics. Appl Environ Microbiol 2019; 85:AEM.02935-18. [PMID: 30658981 DOI: 10.1128/aem.02935-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 01/10/2019] [Indexed: 12/21/2022] Open
Abstract
The canonical pathway for sucrose metabolism in haloarchaea utilizes a modified Embden-Meyerhof-Parnas pathway (EMP), in which ketohexokinase and 1-phosphofructokinase phosphorylate fructose released from sucrose hydrolysis. However, our survey of haloarchaeal genomes determined that ketohexokinase and 1-phosphofructokinase genes were not present in all species known to utilize fructose and sucrose, thereby indicating that alternative mechanisms exist for fructose metabolism. A fructokinase gene was identified in the majority of fructose- and sucrose-utilizing species, whereas only a small number possessed a ketohexokinase gene. Analysis of a range of hypersaline metagenomes revealed that haloarchaeal fructokinase genes were far more abundant (37 times) than haloarchaeal ketohexokinase genes. We used proteomic analysis of Halohasta litchfieldiae (which encodes fructokinase) and identified changes in protein abundance that relate to growth on sucrose. Proteins inferred to be involved in sucrose metabolism included fructokinase, a carbohydrate primary transporter, a putative sucrose hydrolase, and two uncharacterized carbohydrate-related proteins encoded in the same gene cluster as fructokinase and the transporter. Homologs of these proteins were present in the genomes of all haloarchaea that use sugars for growth. Enzymes involved in the semiphosphorylative Entner-Doudoroff pathway also had higher abundances in sucrose-grown H. litchfieldiae cells, consistent with this pathway functioning in the catabolism of the glucose moiety of sucrose. The study revises the current understanding of fundamental pathways for sugar utilization in haloarchaea and proposes alternatives to the modified EMP pathway used by haloarchaea for sucrose and fructose utilization.IMPORTANCE Our ability to infer the function that microorganisms perform in the environment is predicated on assumptions about metabolic capacity. When genomic or metagenomic data are used, metabolic capacity is inferred from genetic potential. Here, we investigate the pathways by which haloarchaea utilize sucrose. The canonical haloarchaeal pathway for fructose metabolism involving ketohexokinase occurs only in a small proportion of haloarchaeal genomes and is underrepresented in metagenomes. Instead, fructokinase genes are present in the majority of genomes/metagenomes. In addition to genomic and metagenomic analyses, we used proteomic analysis of Halohasta litchfieldiae (which encodes fructokinase but lacks ketohexokinase) and identified changes in protein abundance that related to growth on sucrose. In this way, we identified novel proteins implicated in sucrose metabolism in haloarchaea, comprising a transporter and various catabolic enzymes (including proteins that are annotated as hypothetical).
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12
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Williams TJ, Liao Y, Ye J, Kuchel RP, Poljak A, Raftery MJ, Cavicchioli R. Cold adaptation of the Antarctic haloarchaea
Halohasta litchfieldiae
and
Halorubrum lacusprofundi. Environ Microbiol 2017; 19:2210-2227. [DOI: 10.1111/1462-2920.13705] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 01/17/2017] [Accepted: 02/08/2017] [Indexed: 12/23/2022]
Affiliation(s)
- Timothy J. Williams
- School of Biotechnology and Biomolecular SciencesThe University of New South WalesSydney New South Wales2052 Australia
| | - Yan Liao
- School of Biotechnology and Biomolecular SciencesThe University of New South WalesSydney New South Wales2052 Australia
| | - Jun Ye
- School of Biotechnology and Biomolecular SciencesThe University of New South WalesSydney New South Wales2052 Australia
- Centre for Marine Bio‐InnovationThe University of New South WalesSydney New South Wales2052 Australia
| | - Rhiannon P. Kuchel
- Electron Microscopy UnitThe University of New South WalesSydney New South Wales2052 Australia
| | - Anne Poljak
- Bioanalytical Mass Spectrometry FacilityThe University of New South WalesSydney New South Wales2052 Australia
| | - Mark J. Raftery
- Bioanalytical Mass Spectrometry FacilityThe University of New South WalesSydney New South Wales2052 Australia
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular SciencesThe University of New South WalesSydney New South Wales2052 Australia
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Salar-García MJ, Bernal V, Pastor JM, Salvador M, Argandoña M, Nieto JJ, Vargas C, Cánovas M. Understanding the interplay of carbon and nitrogen supply for ectoines production and metabolic overflow in high density cultures of Chromohalobacter salexigens. Microb Cell Fact 2017; 16:23. [PMID: 28179004 PMCID: PMC5299690 DOI: 10.1186/s12934-017-0643-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 02/01/2017] [Indexed: 01/27/2023] Open
Abstract
Background The halophilic bacterium Chromohalobacter salexigens has been proposed as promising cell factory for the production of the compatible solutes ectoine and hydroxyectoine. This bacterium has evolved metabolic adaptations to efficiently grow under high salt concentrations by accumulating ectoines as compatible solutes. However, metabolic overflow, which is a major drawback for the efficient conversion of biological feedstocks, occurs as a result of metabolic unbalances during growth and ectoines production. Optimal production of ectoines is conditioned by the interplay of carbon and nitrogen metabolisms. In this work, we set out to determine how nitrogen supply affects the production of ectoines. Results Chromohalobacter salexigens was challenged to grow in media with unbalanced carbon/nitrogen ratio. In C. salexigens, overflow metabolism and ectoines production are a function of medium composition. At low ammonium conditions, the growth rate decreased importantly, up to 80%. Shifts in overflow metabolism were observed when changing the C/N ratio in the culture medium. 13C-NMR analysis of ectoines labelling revealed a high metabolic rigidity, with almost constant flux ratios in all conditions assayed. Unbalanced C/N ratio led to pyruvate accumulation, especially upon N-limitation. Analysis of an ect− mutant demonstrated the link between metabolic overflow and ectoine biosynthesis. Under non ectoine synthesizing conditions, glucose uptake and metabolic overflow decreased importantly. Finally, in fed-batch cultures, biomass yield was affected by the feeding scheme chosen. High growth (up to 42.4 g L−1) and volumetric ectoine yields (up to 4.21 g L−1) were obtained by minimizing metabolite overflow and nutrient accumulation in high density cultures in a low nitrogen fed-batch culture. Moreover, the yield coefficient calculated for the transformation of glucose into biomass was 30% higher in fed-batch than in the batch culture, demonstrating that the metabolic efficiency of C. salexigens can be improved by careful design of culture feeding schemes. Conclusions Metabolic shifts observed at low ammonium concentrations were explained by a shift in the energy required for nitrogen assimilation. Carbon-limited fed-batch cultures with reduced ammonium supply were the best conditions for cultivation of C. salexigens, supporting high density growth and maintaining high ectoines production. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0643-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- María J Salar-García
- Departamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", 30100, Murcia, Spain.,Departamento de Ingeniería Química y Ambiental, Universidad Politécnica de Cartagena, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", Campus Muralla del MarCalle Doctor Fleming S/N, 30202, Cartagena, Spain
| | - Vicente Bernal
- Departamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", 30100, Murcia, Spain. .,Área de Biología, Dirección de Tecnología Química y Nuevas Energías, Centro de Tecnología de Repsol S.A., Ctra. de Extremadura A-5, Km. 18, 28375, Móstoles, Spain.
| | - José M Pastor
- Departamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", 30100, Murcia, Spain
| | - Manuel Salvador
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, 41012, Seville, Spain
| | - Montserrat Argandoña
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, 41012, Seville, Spain
| | - Joaquín J Nieto
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, 41012, Seville, Spain
| | - Carmen Vargas
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, 41012, Seville, Spain
| | - Manuel Cánovas
- Departamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", 30100, Murcia, Spain.
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14
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Williams TJ, Allen M, Tschitschko B, Cavicchioli R. Glycerol metabolism of haloarchaea. Environ Microbiol 2016; 19:864-877. [PMID: 27768817 DOI: 10.1111/1462-2920.13580] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Haloarchaea are heterotrophic members of the Archaea that thrive in hypersaline environments, often feeding off the glycerol that is produced as an osmolyte by eucaryotic Dunaliella during primary production. In this study we analyzed glycerol metabolism genes in closed genomes of haloarchaea and examined published data describing the growth properties of haloarchaea and experimental data for the enzymes involved. By integrating the genomic data with knowledge from the literature, we derived an understanding of the ecophysiology and evolutionary properties of glycerol catabolic pathways in haloarchaea.
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Affiliation(s)
- Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, New South Wales, Australia
| | - Michelle Allen
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, New South Wales, Australia
| | - Bernhard Tschitschko
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, New South Wales, Australia
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, New South Wales, Australia
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15
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Oren A. Glycerol metabolism in hypersaline environments. Environ Microbiol 2016; 19:851-863. [DOI: 10.1111/1462-2920.13493] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/05/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Aharon Oren
- The Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus; Jerusalem 91904 Israel
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16
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Probing Saltern Brines with an Oxygen Electrode: What Can We Learn about the Community Metabolism in Hypersaline Systems? Life (Basel) 2016; 6:life6020023. [PMID: 27338478 PMCID: PMC4931460 DOI: 10.3390/life6020023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 11/23/2022] Open
Abstract
We have explored the use of optical oxygen electrodes to study oxygenic photosynthesis and heterotrophic activities in crystallizer brines of the salterns in Eilat, Israel. Monitoring oxygen uptake rates in the dark enables the identification of organic substrates that are preferentially used by the community. Addition of glycerol (the osmotic solute synthesized by Dunaliella) or dihydroxyacetone (produced from glycerol by Salinibacter) enhanced respiration rates. Pyruvate, produced from glycerol or from some sugars by certain halophilic Archaea also stimulated community respiration. Fumarate had a sparing effect on respiration, possibly as many halophilic Archaea can use fumarate as a terminal electron acceptor in respiration. Calculating the photosynthetic activity of Dunaliella by monitoring oxygen concentration changes during light/dark incubations is not straightforward as light also affects respiration of some halophilic Archaea and Bacteria due to action of light-driven proton pumps. When illuminated, community respiration of brine samples in which oxygenic photosynthesis was inhibited by DCMU decreased by ~40%. This effect was interpreted as the result of competition between two energy yielding systems: the bacteriorhodopsin proton pump and the respiratory chain of the prokaryotes. These findings have important implications for the interpretation of other published data on photosynthetic and respiratory activities in hypersaline environments.
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