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Tu W, Saeed H, Huang WE. Rhodopsin-based light-harvesting system for sustainable synthetic biology. Microb Biotechnol 2024; 17:e14521. [PMID: 38949508 PMCID: PMC11215838 DOI: 10.1111/1751-7915.14521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/17/2024] [Indexed: 07/02/2024] Open
Abstract
Rhodopsins, a diverse class of light-sensitive proteins found in various life domains, have attracted considerable interest for their potential applications in sustainable synthetic biology. These proteins exhibit remarkable photochemical properties, undergoing conformational changes upon light absorption that drive a variety of biological processes. Exploiting rhodopsin's natural properties could pave the way for creating sustainable and energy-efficient technologies. Rhodopsin-based light-harvesting systems offer innovative solutions to a few key challenges in sustainable engineering, from bioproduction to renewable energy conversion. In this opinion article, we explore the recent advancements and future possibilities of employing rhodopsins for sustainable engineering, underscoring the transformative potential of these biomolecules.
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Affiliation(s)
- Weiming Tu
- Department of Engineering ScienceUniversity of OxfordOxfordUK
| | - Haris Saeed
- Department of Engineering ScienceUniversity of OxfordOxfordUK
| | - Wei E. Huang
- Department of Engineering ScienceUniversity of OxfordOxfordUK
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Li S, Yin L, Duan L, Li J, Wang P, Gao S, Xian W, Li W. Diversity, abundance, and expression of proteorhodopsin genes in the northern South China Sea. ENVIRONMENTAL RESEARCH 2024; 259:119514. [PMID: 38950812 DOI: 10.1016/j.envres.2024.119514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 06/28/2024] [Accepted: 06/29/2024] [Indexed: 07/03/2024]
Abstract
Proteorhodopsins have been suggested as an important strategy among phototrophs to capture solar energy in marine environments. The goals of this study was to investigate the diversity of proteorhodopsin genes and to explore their abundance, distribution, and expression in the coastal surface waters of the northern South China Sea, one of the largest marginal seas of the western North Pacific Ocean. Using 21 metagenomes, we recovered proteorhodopsin genes from a wide range of prokaryotic taxa, and chlorophyll a contributed significantly to the community composition of proteorhodopsin-containing microbes. Most proteorhodopsin sequences were predicted to encode green light-absorbing proton pumps and green light-absorbing proteorhodopsin genes were more abundant than blue-absorbing ones. The variations in the conserved residues involved in ion pumping and several uncharacterized proteorhodopsins were observed. The gene abundance pattern of proteorhodopsin types were significantly influenced by the levels of total organic carbon and soluble reactive phosphorus. Gene expression analysis confirmed the importance of proteorhodopsin-based phototrophy and revealed different expressional patterns among major phyla. In tandem, we screened 2295 metagenome-assembled genomes to describe the taxonomic distribution of proteorhodopsins. Bacteroidota are the key lineages encoding proteorhodopsins, but proteorhodopsins were predicated from members of Proteobacteria, Marinisomatota, Myxococcota, Verrucomicrobiota and Thermoplasmatota. Our study expanded the diversity of proteorhodopsins and improve our understanding on the significance of proteorhodopsin-mediated phototrophy in the marine ecosystem.
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Affiliation(s)
- Shanhui Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences & School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Lingzi Yin
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences & School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Li Duan
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences & School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Jialing Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences & School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Pandeng Wang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences & School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Shaoming Gao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences & School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Wendong Xian
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences & School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China; Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, 316000, China
| | - Wenjun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences & School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China.
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Mao J, Jin X, Shi M, Heidenreich D, Brown LJ, Brown RCD, Lelli M, He X, Glaubitz C. Molecular mechanisms and evolutionary robustness of a color switch in proteorhodopsins. SCIENCE ADVANCES 2024; 10:eadj0384. [PMID: 38266078 PMCID: PMC10807816 DOI: 10.1126/sciadv.adj0384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024]
Abstract
Proteorhodopsins are widely distributed photoreceptors from marine bacteria. Their discovery revealed a high degree of evolutionary adaptation to ambient light, resulting in blue- and green-absorbing variants that correlate with a conserved glutamine/leucine at position 105. On the basis of an integrated approach combining sensitivity-enhanced solid-state nuclear magnetic resonance (ssNMR) spectroscopy and linear-scaling quantum mechanics/molecular mechanics (QM/MM) methods, this single residue is shown to be responsible for a variety of synergistically coupled structural and electrostatic changes along the retinal polyene chain, ionone ring, and within the binding pocket. They collectively explain the observed color shift. Furthermore, analysis of the differences in chemical shift between nuclei within the same residues in green and blue proteorhodopsins also reveals a correlation with the respective degree of conservation. Our data show that the highly conserved color change mainly affects other highly conserved residues, illustrating a high degree of robustness of the color phenotype to sequence variation.
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Affiliation(s)
- Jiafei Mao
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Xinsheng Jin
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - Man Shi
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - David Heidenreich
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Lynda J. Brown
- Department of Chemistry, University of Southampton, Southampton, SO17 1BJ UK
| | - Richard C. D. Brown
- Department of Chemistry, University of Southampton, Southampton, SO17 1BJ UK
| | - Moreno Lelli
- Department of Chemistry “Ugo Schiff” and Magnetic Resonance Center (CERM), University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Italy
- Consorzio Interuniversitario Risonanze Magnetiche MetalloProteine (CIRMMP), Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Italy
| | - Xiao He
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
- New York University–East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai, 200062, China
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Straße 9, 60438 Frankfurt am Main, Germany
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Selvaraj MK, Thakur A, Kumar M, Pinnaka AK, Suri CR, Siddhardha B, Elumalai SP. Ion-pumping microbial rhodopsin protein classification by machine learning approach. BMC Bioinformatics 2023; 24:29. [PMID: 36707759 PMCID: PMC9881276 DOI: 10.1186/s12859-023-05138-x] [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] [Received: 07/13/2022] [Accepted: 01/04/2023] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Rhodopsin is a seven-transmembrane protein covalently linked with retinal chromophore that absorbs photons for energy conversion and intracellular signaling in eukaryotes, bacteria, and archaea. Haloarchaeal rhodopsins are Type-I microbial rhodopsin that elicits various light-driven functions like proton pumping, chloride pumping and Phototaxis behaviour. The industrial application of Ion-pumping Haloarchaeal rhodopsins is limited by the lack of full-length rhodopsin sequence-based classifications, which play an important role in Ion-pumping activity. The well-studied Haloarchaeal rhodopsin is a proton-pumping bacteriorhodopsin that shows promising applications in optogenetics, biosensitized solar cells, security ink, data storage, artificial retinal implant and biohydrogen generation. As a result, a low-cost computational approach is required to identify Ion-pumping Haloarchaeal rhodopsin sequences and its subtype. RESULTS This study uses a support vector machine (SVM) technique to identify these ion-pumping Haloarchaeal rhodopsin proteins. The haloarchaeal ion pumping rhodopsins viz., bacteriorhodopsin, halorhodopsin, xanthorhodopsin, sensoryrhodopsin and marine prokaryotic Ion-pumping rhodopsins like actinorhodopsin, proteorhodopsin have been utilized to develop the methods that accurately identified the ion pumping haloarchaeal and other type I microbial rhodopsins. We achieved overall maximum accuracy of 97.78%, 97.84% and 97.60%, respectively, for amino acid composition, dipeptide composition and hybrid approach on tenfold cross validation using SVM. Predictive models for each class of rhodopsin performed equally well on an independent data set. In addition to this, similar results were achieved using another machine learning technique namely random forest. Simultaneously predictive models performed equally well during five-fold cross validation. Apart from this study, we also tested the own, blank, BLAST dataset and annotated whole-genome rhodopsin sequences of PWS haloarchaeal isolates in the developed methods. The developed web server ( https://bioinfo.imtech.res.in/servers/rhodopred ) can identify the Ion Pumping Haloarchaeal rhodopsin proteins and their subtypes. We expect this web tool would be useful for rhodopsin researchers. CONCLUSION The overall performance of the developed method results show that it accurately identifies the Ionpumping Haloarchaeal rhodopsin and their subtypes using known and unknown microbial rhodopsin sequences. We expect that this study would be useful for optogenetics, molecular biologists and rhodopsin researchers.
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Affiliation(s)
- Muthu Krishnan Selvaraj
- grid.418099.dMTCC-Microbial Type Culture Collection and Gene Bank, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Anamika Thakur
- grid.418099.dVirology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Manoj Kumar
- grid.418099.dVirology Unit and Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Anil Kumar Pinnaka
- grid.418099.dMTCC-Microbial Type Culture Collection and Gene Bank, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Chander Raman Suri
- grid.418099.dBiosensor Department, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
| | - Busi Siddhardha
- grid.412517.40000 0001 2152 9956Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, 605014 India
| | - Senthil Prasad Elumalai
- grid.418099.dBiochemical Engineering Research and Process Development Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR-IMTECH), Chandigarh, 160036 India
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Alonso-Reyes DG, Galván FS, Irazoqui JM, Amadio A, Tschoeke D, Thompson F, Albarracín VH, Farias ME. Dissecting Light Sensing and Metabolic Pathways on the Millimeter Scale in High-Altitude Modern Stromatolites. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02112-7. [PMID: 36161499 DOI: 10.1007/s00248-022-02112-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
Modern non-lithifying stromatolites on the shore of the volcanic lake Socompa (SST) in the Puna are affected by several extreme conditions. The present study assesses for the first time light utilization and functional metabolic stratification of SST on a millimeter scale through shotgun metagenomics. In addition, a scanning-electron-microscopy approach was used to explore the community. The analysis on SST unveiled the profile of a photosynthetic mat, with cyanobacteria not directly exposed to light, but placed just below a high-UV-resistant community. Calvin-Benson and 3-hydroxypropinate cycles for carbon fixation were abundant in upper, oxic layers, while the Wood-Ljungdahl pathway was dominant in the deeper anoxic strata. The high abundance of genes for UV-screening and oxidant-quenching pigments and CPF (photoreactivation) in the UV-stressed layers could indicate that the zone itself works as a UV shield. There is a remarkable density of sequences associated with photoreceptors in the first two layers. Also, genetic evidence of photosynthesis split in eukaryotic (layer 1) and prokaryotic (layer 2). Photoheterotrophic bacteria, aerobic photoautotrophic bacteria, and anaerobic photoautotrophic bacteria coexist by selectively absorbing different parts of the light spectrum (blue, red, and IR respectively) at different positions of the mat. Genes for oxygen, nitrogen, and sulfur metabolism account for the microelectrode chemical data and pigment measurements performed in previous publications. We also provide here an explanation for the vertical microbial mobility within the SST described previously. Finally, our study points to SST as ideal modern analogues of ancient ST.
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Affiliation(s)
- Daniel Gonzalo Alonso-Reyes
- Laboratorio de Microbiología Ultraestructural Y Molecular, Centro Integral de Microscopía Electrónica (CIME,), CONICET-Universidad Nacional de Tucumán, Camino de Sirga s/n, Finca El Manantial, Yerba Buena (4107), San Miguel de Tucumán, Tucumán, Argentina
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales y Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina
| | - Fátima Silvina Galván
- Laboratorio de Microbiología Ultraestructural Y Molecular, Centro Integral de Microscopía Electrónica (CIME,), CONICET-Universidad Nacional de Tucumán, Camino de Sirga s/n, Finca El Manantial, Yerba Buena (4107), San Miguel de Tucumán, Tucumán, Argentina
| | - José Matías Irazoqui
- Instituto de Investigación de La Cadena Láctea (INTA-CONICET), Rafaela, Argentina
| | - Ariel Amadio
- Instituto de Investigación de La Cadena Láctea (INTA-CONICET), Rafaela, Argentina
| | - Diogo Tschoeke
- Institute of Biology and Coppe, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabiano Thompson
- Institute of Biology and Coppe, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Virginia Helena Albarracín
- Laboratorio de Microbiología Ultraestructural Y Molecular, Centro Integral de Microscopía Electrónica (CIME,), CONICET-Universidad Nacional de Tucumán, Camino de Sirga s/n, Finca El Manantial, Yerba Buena (4107), San Miguel de Tucumán, Tucumán, Argentina.
- Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Tucumán, Argentina.
| | - María Eugenia Farias
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales y Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina
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The microbiome of a bacterivorous marine choanoflagellate contains a resource-demanding obligate bacterial associate. Nat Microbiol 2022; 7:1466-1479. [PMID: 35970961 PMCID: PMC9418006 DOI: 10.1038/s41564-022-01174-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 06/14/2022] [Indexed: 11/08/2022]
Abstract
Microbial predators such as choanoflagellates are key players in ocean food webs. Choanoflagellates, which are the closest unicellular relatives of animals, consume bacteria and also exhibit marked biological transitions triggered by bacterial compounds, yet their native microbiomes remain uncharacterized. Here we report the discovery of a ubiquitous, uncultured bacterial lineage we name Candidatus Comchoanobacterales ord. nov., related to the human pathogen Coxiella and physically associated with the uncultured marine choanoflagellate Bicosta minor. We analyse complete ‘Comchoano’ genomes acquired after sorting single Bicosta cells, finding signatures of obligate host-dependence, including reduction of pathways encoding glycolysis, membrane components, amino acids and B-vitamins. Comchoano encode the necessary apparatus to import energy and other compounds from the host, proteins for host-cell associations and a type IV secretion system closest to Coxiella’s that is expressed in Pacific Ocean metatranscriptomes. Interactions between choanoflagellates and their microbiota could reshape the direction of energy and resource flow attributed to microbial predators, adding complexity and nuance to marine food webs. Choanoflagellates are the closest living unicellular relatives of animals and are important bacterivorous predators in the ocean. Here the authors show that the microbiome of this predator includes an obligate, host resource-dependent bacterial associate.
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Genome Streamlining, Proteorhodopsin, and Organic Nitrogen Metabolism in Freshwater Nitrifiers. mBio 2022; 13:e0237921. [PMID: 35435701 PMCID: PMC9239080 DOI: 10.1128/mbio.02379-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Microbial nitrification is a critical process governing nitrogen availability in aquatic systems. Freshwater nitrifiers have received little attention, leaving many unanswered questions about their taxonomic distribution, functional potential, and ecological interactions. Here, we reconstructed genomes to infer the metabolism and ecology of free-living picoplanktonic nitrifiers across the Laurentian Great Lakes, a connected series of five of Earth’s largest lakes. Surprisingly, ammonia-oxidizing bacteria (AOB) related to Nitrosospira dominated over ammonia-oxidizing archaea (AOA) at nearly all stations, with distinct ecotypes prevailing in the transparent, oligotrophic upper lakes compared to Lakes Erie and Ontario. Unexpectedly, one ecotype of Nitrosospira encodes proteorhodopsin, which could enhance survival under conditions where ammonia oxidation is inhibited or substrate limited. Nitrite-oxidizing bacteria (NOB) “Candidatus Nitrotoga” and Nitrospira fluctuated in dominance, with the latter prevailing in deeper, less-productive basins. Genome reconstructions reveal highly reduced genomes and features consistent with genome streamlining, along with diverse adaptations to sunlight and oxidative stress and widespread capacity for organic nitrogen use. Our findings expand the known functional diversity of nitrifiers and establish their ecological genomics in large lake ecosystems. By elucidating links between microbial biodiversity and biogeochemical cycling, our work also informs ecosystem models of the Laurentian Great Lakes, a critical freshwater resource experiencing rapid environmental change.
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Vanni C, Schechter MS, Acinas SG, Barberán A, Buttigieg PL, Casamayor EO, Delmont TO, Duarte CM, Eren AM, Finn RD, Kottmann R, Mitchell A, Sánchez P, Siren K, Steinegger M, Gloeckner FO, Fernàndez-Guerra A. Unifying the known and unknown microbial coding sequence space. eLife 2022; 11:67667. [PMID: 35356891 PMCID: PMC9132574 DOI: 10.7554/elife.67667] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 03/30/2022] [Indexed: 12/02/2022] Open
Abstract
Genes of unknown function are among the biggest challenges in molecular biology, especially in microbial systems, where 40–60% of the predicted genes are unknown. Despite previous attempts, systematic approaches to include the unknown fraction into analytical workflows are still lacking. Here, we present a conceptual framework, its translation into the computational workflow AGNOSTOS and a demonstration on how we can bridge the known-unknown gap in genomes and metagenomes. By analyzing 415,971,742 genes predicted from 1749 metagenomes and 28,941 bacterial and archaeal genomes, we quantify the extent of the unknown fraction, its diversity, and its relevance across multiple organisms and environments. The unknown sequence space is exceptionally diverse, phylogenetically more conserved than the known fraction and predominantly taxonomically restricted at the species level. From the 71 M genes identified to be of unknown function, we compiled a collection of 283,874 lineage-specific genes of unknown function for Cand. Patescibacteria (also known as Candidate Phyla Radiation, CPR), which provides a significant resource to expand our understanding of their unusual biology. Finally, by identifying a target gene of unknown function for antibiotic resistance, we demonstrate how we can enable the generation of hypotheses that can be used to augment experimental data. It is estimated that scientists do not know what half of microbial genes actually do. When these genes are discovered in microorganisms grown in the lab or found in environmental samples, it is not possible to identify what their roles are. Many of these genes are excluded from further analyses for these reasons, meaning that the study of microbial genes tends to be limited to genes that have already been described. These limitations hinder research into microbiology, because information from newly discovered genes cannot be integrated to better understand how these organisms work. Experiments to understand what role these genes have in the microorganisms are labor-intensive, so new analytical strategies are needed. To do this, Vanni et al. developed a new framework to categorize genes with unknown roles, and a computational workflow to integrate them into traditional analyses. When this approach was applied to over 400 million microbial genes (both with known and unknown roles), it showed that the share of genes with unknown functions is only about 30 per cent, smaller than previously thought. The analysis also showed that these genes are very diverse, revealing a huge space for future research and potential applications. Combining their approach with experimental data, Vanni et al. were able to identify a gene with a previously unknown purpose that could be involved in antibiotic resistance. This system could be useful for other scientists studying microorganisms to get a more complete view of microbial systems. In future, it may also be used to analyze the genetics of other organisms, such as plants and animals.
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Affiliation(s)
- Chiara Vanni
- Microbial Genomics and Bioinformatics Research G, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | | | - Silvia G Acinas
- Department of Marine Biology and Oceanography, Institut de Ciències del Mar-CMIMA (CSIC), Barcelona, Spain
| | - Albert Barberán
- Department of Environmental Science, University of Arizona, Tucson, United States
| | - Pier Luigi Buttigieg
- Helmholtz Centre for Polar and Marine Research, Alfred Wegener Institute, Bremerhaven, Germany
| | - Emilio O Casamayor
- Center for Advanced Studies of Blanes CEAB-CSIC, Spanish Council for Research, Blanes, Spain
| | - Tom O Delmont
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Paris, France
| | - Carlos M Duarte
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - A Murat Eren
- Department of Medicine, University of Chicago, Chicago, United States
| | - Robert D Finn
- European Bioinformatics Institute (EMBL-EBI), European Molecular Biology Laboratory, Hinxton, United Kingdom
| | - Renzo Kottmann
- Microbial Genomics and Bioinformatics Research G, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Alex Mitchell
- European Bioinformatics Institute (EMBL-EBI), European Molecular Biology Laboratory, Hinxton, United Kingdom
| | - Pablo Sánchez
- Department of Marine Biology and Oceanography, Institut de Ciències del Mar-CMIMA (CSIC), Barcelona, Spain
| | - Kimmo Siren
- Section for Evolutionary Genomics, The GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Martin Steinegger
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Frank Oliver Gloeckner
- MARUM, Helmholtz Center for Polar and Marine Research, University of Bremen, Bremen, Germany
| | - Antonio Fernàndez-Guerra
- Lundbeck Foundation GeoGenetics Centre, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
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Haro-Moreno JM, López-Pérez M, Rodriguez-Valera F. Enhanced Recovery of Microbial Genes and Genomes From a Marine Water Column Using Long-Read Metagenomics. Front Microbiol 2021; 12:708782. [PMID: 34512586 PMCID: PMC8430335 DOI: 10.3389/fmicb.2021.708782] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
Third-generation sequencing has penetrated little in metagenomics due to the high error rate and dependence for assembly on short-read designed bioinformatics. However, second-generation sequencing metagenomics (mostly Illumina) suffers from limitations, particularly in the assembly of microbes with high microdiversity and retrieval of the flexible (adaptive) fraction of prokaryotic genomes. Here, we have used a third-generation technique to study the metagenome of a well-known marine sample from the mixed epipelagic water column of the winter Mediterranean. We have compared PacBio Sequel II with the classical approach using Illumina Nextseq short reads followed by assembly to study the metagenome. Long reads allow for efficient direct retrieval of complete genes avoiding the bias of the assembly step. Besides, the application of long reads on metagenomic assembly allows for the reconstruction of much more complete metagenome-assembled genomes (MAGs), particularly from microbes with high microdiversity such as Pelagibacterales. The flexible genome of reconstructed MAGs was much more complete containing many adaptive genes (some with biotechnological potential). PacBio Sequel II CCS appears particularly suitable for cellular metagenomics due to its low error rate. For most applications of metagenomics, from community structure analysis to ecosystem functioning, long reads should be applied whenever possible. Specifically, for in silico screening of biotechnologically useful genes, or population genomics, long-read metagenomics appears presently as a very fruitful approach and can be analyzed from raw reads before a computationally demanding (and potentially artifactual) assembly step.
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Affiliation(s)
- Jose M. Haro-Moreno
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, Alicante, Spain
| | - Mario López-Pérez
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, Alicante, Spain
| | - Francisco Rodriguez-Valera
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, Alicante, Spain
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
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Abstract
Microbial proton-pumping rhodopsins are considered the simplest strategy among phototrophs to conserve energy from light. Proteorhodopsins are the most studied rhodopsins thus far because of their ubiquitous presence in the ocean, except in Antarctica, where they remain understudied. We analyzed proteorhodopsin abundance and transcriptional activity in the Western Antarctic coastal seawaters. Combining quantitative PCR (qPCR) and metagenomics, the relative abundance of proteorhodopsin-bearing bacteria accounted on average for 17, 3.5, and 29.7% of the bacterial community in Chile Bay (South Shetland Islands) during 2014, 2016, and 2017 summer-autumn, respectively. The abundance of proteorhodopsin-bearing bacteria changed in relation to environmental conditions such as chlorophyll a and temperature. Alphaproteobacteria, Gammaproteobacteria, and Flavobacteriia were the main bacteria that transcribed the proteorhodopsin gene during day and night. Although green light-absorbing proteorhodopsin genes were more abundant than blue-absorbing ones, the latter were transcribed more intensely, resulting in >50% of the proteorhodopsin transcripts during the day and night. Flavobacteriia were the most abundant proteorhodopsin-bearing bacteria in the metagenomes; however, Alphaproteobacteria and Gammaproteobacteria were more represented in the metatranscriptomes, with qPCR quantification suggesting the dominance of the active SAR11 clade. Our results show that proteorhodopsin-bearing bacteria are prevalent in Antarctic coastal waters in late austral summer and early autumn, and their ecological relevance needs to be elucidated to better understand how sunlight energy is used in this marine ecosystem. IMPORTANCE Proteorhodopsin-bearing microorganisms in the Southern Ocean have been overlooked since their discovery in 2000. The present study identify taxonomy and quantify the relative abundance of proteorhodopsin-bearing bacteria and proteorhodopsin gene transcription in the West Antarctic Peninsula's coastal waters. This information is crucial to understand better how sunlight enters this marine environment through alternative ways unrelated to chlorophyll-based strategies. The relative abundance of proteorhodopsin-bearing bacteria seems to be related to environmental parameters (e.g., chlorophyll a, temperature) that change yearly at the coastal water of the West Antarctic Peninsula during the austral late summers and early autumns. Proteorhodopsin-bearing bacteria from Antarctic coastal waters are potentially able to exploit both the green and blue spectrum of sunlight and are a prevalent group during the summer in this polar environment.
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Boeuf D, Eppley JM, Mende DR, Malmstrom RR, Woyke T, DeLong EF. Metapangenomics reveals depth-dependent shifts in metabolic potential for the ubiquitous marine bacterial SAR324 lineage. MICROBIOME 2021; 9:172. [PMID: 34389059 PMCID: PMC8364033 DOI: 10.1186/s40168-021-01119-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 06/22/2021] [Indexed: 06/01/2023]
Abstract
BACKGROUND Oceanic microbiomes play a pivotal role in the global carbon cycle and are central to the transformation and recycling of carbon and energy in the ocean's interior. SAR324 is a ubiquitous but poorly understood uncultivated clade of Deltaproteobacteria that inhabits the entire water column, from ocean surface waters to its deep interior. Although some progress has been made in elucidating potential metabolic traits of SAR324 in the dark ocean, very little is known about the ecology and the metabolic capabilities of this group in the euphotic and twilight zones. To investigate the comparative genomics, ecology, and physiological potential of the SAR324 clade, we examined the distribution and variability of key genomic features and metabolic pathways in this group from surface waters to the abyss in the North Pacific Subtropical Gyre, one of the largest biomes on Earth. RESULTS We leveraged a pangenomic ecological approach, combining spatio-temporally resolved single-amplified genome, metagenomic, and metatranscriptomic datasets. The data revealed substantial genomic diversity throughout the SAR324 clade, with distinct depth and temporal distributions that clearly differentiated ecotypes. Phylogenomic subclade delineation, environmental distributions, genomic feature similarities, and metabolic capacities revealed strong congruence. The four SAR324 ecotypes delineated in this study revealed striking divergence from one another with respect to their habitat-specific metabolic potentials. The ecotypes living in the dark or twilight oceans shared genomic features and metabolic capabilities consistent with a sulfur-based chemolithoautotrophic lifestyle. In contrast, those inhabiting the sunlit ocean displayed higher plasticity energy-related metabolic pathways, supporting a presumptive photoheterotrophic lifestyle. In epipelagic SAR324 ecotypes, we observed the presence of two types of proton-pumping rhodopsins, as well as genomic, transcriptomic, and ecological evidence for active photoheterotrophy, based on xanthorhodopsin-like light-harvesting proteins. CONCLUSIONS Combining pangenomic and both metagenomic and metatranscriptomic profiling revealed a striking divergence in the vertical distribution, genomic composition, metabolic potential, and predicted lifestyle strategies of geographically co-located members of the SAR324 bacterial clade. The results highlight the utility of metapangenomic approaches employed across environmental gradients, to decipher the properties and variation in function and ecological traits of specific phylogenetic clades within complex microbiomes. Video abstract.
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Affiliation(s)
- Dominique Boeuf
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii, Manoa, Honolulu, HI 96822 USA
| | - John M. Eppley
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii, Manoa, Honolulu, HI 96822 USA
| | - Daniel R. Mende
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii, Manoa, Honolulu, HI 96822 USA
| | | | - Tanja Woyke
- DOE Joint Genome Institute, Berkeley, CA 94720 USA
| | - Edward F. DeLong
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii, Manoa, Honolulu, HI 96822 USA
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Abstract
Rhodopsins, most of which are proton pumps generating transmembrane electrochemical proton gradients, span all three domains of life, are abundant in the biosphere, and could play a crucial role in the early evolution of life on earth. Whereas archaeal and bacterial proton pumps are among the best structurally characterized proteins, rhodopsins from unicellular eukaryotes have not been well characterized. To fill this gap in the current understanding of the proton pumps and to gain insight into the evolution of rhodopsins using a structure-based approach, we performed a structural and functional analysis of the light-driven proton pump LR (Mac) from the pathogenic fungus Leptosphaeria maculans. The first high-resolution structure of fungi rhodopsin and its functional properties reveal the striking similarity of its membrane part to archaeal but not to bacterial rhodopsins. We show that an unusually long N-terminal region stabilizes the protein through direct interaction with its extracellular loop (ECL2). We compare to our knowledge all available structures and sequences of outward light-driven proton pumps and show that eukaryotic and archaeal proton pumps, most likely, share a common ancestor. Zabelskii et al. present a structural and functional analysis of the lightdriven proton pump LR (Mac) from the fungus Leptosphaeria maculans. Their findings indicate that the archaeal ancestry of eukaryotic type 1 rhodopsins, and that the archaeal host of the proto-mitochondrial endosymbiont was capable of light-driven proton pumping.
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Pereira O, Hochart C, Boeuf D, Auguet JC, Debroas D, Galand PE. Seasonality of archaeal proteorhodopsin and associated Marine Group IIb ecotypes (Ca. Poseidoniales) in the North Western Mediterranean Sea. THE ISME JOURNAL 2021; 15:1302-1316. [PMID: 33288859 PMCID: PMC8115670 DOI: 10.1038/s41396-020-00851-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/09/2020] [Accepted: 11/18/2020] [Indexed: 01/04/2023]
Abstract
The Archaea Marine Group II (MGII) is widespread in the world's ocean where it plays an important role in the carbon cycle. Despite recent discoveries on the group's metabolisms, the ecology of this newly proposed order (Candidatus Poseidoniales) remains poorly understood. Here we used a combination of time-series metagenome-assembled genomes (MAGs) and high-frequency 16S rRNA data from the NW Mediterranean Sea to test if the taxonomic diversity within the MGIIb family (Candidatus Thalassarchaeaceae) reflects the presence of different ecotypes. The MAGs' seasonality revealed a MGIIb family composed of different subclades that have distinct lifestyles and physiologies. The vitamin metabolisms were notably different between ecotypes with, in some, a possible link to sunlight's energy. Diverse archaeal proteorhodopsin variants, with unusual signature in key amino acid residues, had distinct seasonal patterns corresponding to changing day length. In addition, we show that in summer, archaea, as opposed to bacteria, disappeared completely from surface waters. Our results shed light on the diversity and the distribution of the euryarchaeotal proteorhodopsin, and highlight that MGIIb is a diverse ecological group. The work shows that time-series based studies of the taxonomy, seasonality, and metabolisms of marine prokaryotes is critical to uncover their diverse role in the ocean.
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Affiliation(s)
- Olivier Pereira
- Sorbonne Universités, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques (LECOB), Observatoire Océanologique, Banyuls sur Mer, France
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Southern University of Science and Technology, Shenzhen, China
| | - Corentin Hochart
- Sorbonne Universités, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques (LECOB), Observatoire Océanologique, Banyuls sur Mer, France
| | - Dominique Boeuf
- Daniel K. Inouye Center for Microbial Oceanography, Research and Education, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, Honolulu, HI, United States, Honolulu, HI, 96822, USA
| | - Jean Christophe Auguet
- MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, Montpellier, France, Montpellier, France
| | - Didier Debroas
- Université Clermont Auvergne, CNRS, Laboratoire Microorganismes: Genome et Environnement, 63000, Clermont-Ferrand, France
| | - Pierre E Galand
- Sorbonne Universités, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques (LECOB), Observatoire Océanologique, Banyuls sur Mer, France.
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Graham ED, Tully BJ. Marine Dadabacteria exhibit genome streamlining and phototrophy-driven niche partitioning. THE ISME JOURNAL 2021; 15:1248-1256. [PMID: 33230264 PMCID: PMC8115339 DOI: 10.1038/s41396-020-00834-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/27/2020] [Accepted: 11/05/2020] [Indexed: 01/29/2023]
Abstract
The remineralization of organic material via heterotrophy in the marine environment is performed by a diverse and varied group of microorganisms that can specialize in the type of organic material degraded and the niche they occupy. The marine Dadabacteria are cosmopolitan in the marine environment and belong to a candidate phylum for which there has not been a comprehensive assessment of the available genomic data to date. Here in, we assess the functional potential of the marine pelagic Dadabacteria in comparison to members of the phylum that originate from terrestrial, hydrothermal, and subsurface environments. Our analysis reveals that the marine pelagic Dadabacteria have streamlined genomes, corresponding to smaller genome sizes and lower nitrogen content of their DNA and predicted proteome, relative to their phylogenetic counterparts. Collectively, the Dadabacteria have the potential to degrade microbial dissolved organic matter, specifically peptidoglycan and phospholipids. The marine Dadabacteria belong to two clades with apparent distinct ecological niches in global metagenomic data: a clade with the potential for photoheterotrophy through the use of proteorhodopsin, present predominantly in surface waters up to 100 m depth; and a clade lacking the potential for photoheterotrophy that is more abundant in the deep photic zone.
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Affiliation(s)
- Elaina D Graham
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Benjamin J Tully
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
- Center for Dark Energy Biosphere Investigations, University of Southern California, Los Angeles, CA, USA.
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15
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Ruiz-Perez CA, Bertagnolli AD, Tsementzi D, Woyke T, Stewart FJ, Konstantinidis KT. Description of Candidatus Mesopelagibacter carboxydoxydans and Candidatus Anoxipelagibacter denitrificans: Nitrate-reducing SAR11 genera that dominate mesopelagic and anoxic marine zones. Syst Appl Microbiol 2021; 44:126185. [PMID: 33676264 DOI: 10.1016/j.syapm.2021.126185] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/25/2020] [Accepted: 12/09/2020] [Indexed: 11/29/2022]
Abstract
The diverse and ubiquitous members of the SAR11 lineage (Alphaproteobacteria) represent up to 30-40% of the surface and mesopelagic oceanic microbial communities. However, the molecular and ecological mechanisms that differentiate closely related, yet distinct, SAR11 members that often co-occur under similar environmental conditions remain speculative. Recently, two mesopelagic and oxygen minimum zone (OMZ)-associated subclades of SAR11 (Ic and IIa.A) were described using single-cell amplified genomes (SAGs) linked to nitrate reduction in OMZs. In this current study, the collection of genomes belonging to these two subclades was expanded with thirteen new metagenome-assembled genomes (MAGs), thus providing a more detailed phylogenetic and functional characterization of these subclades. Gene content-based predictions of metabolic functions revealed similarities in central carbon metabolism between subclades Ic and IIa.A and surface SAR11 clades, with small variations in central pathways. These variations included more versatile sulfur assimilation pathways, as well as a previously predicted capacity for nitrate reduction that conferred unique versatility on mesopelagic-adapted clades compared to their surface counterparts. Finally, consistent with previously reported abundances of carbon monoxide (CO) in surface and mesopelagic waters, subclades Ia (surface) and Ic (mesopelagic) have the genetic potential to oxidize carbon monoxide (CO), presumably taking advantage of this abundant compound as an electron donor. Based on genomic analyses, environmental distribution and metabolic reconstruction, we propose two new SAR11 genera, Ca. Mesopelagibacter carboxydoxydans (subclade Ic) and Ca. Anoxipelagibacter denitrificans (subclade IIa.A), which represent members of the mesopelagic and OMZ-adapted SAR11 clades.
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Affiliation(s)
- Carlos A Ruiz-Perez
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Anthony D Bertagnolli
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Despina Tsementzi
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Tanja Woyke
- DOE Joint Genome Institute, One Cyclotron Road, Mail Stop 91R0183, Berkeley, CA 94720, USA
| | - Frank J Stewart
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA; Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA 30332, USA; Department of Microbiology & Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Konstantinos T Konstantinidis
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA; School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Center for Bioinformatics and Computational Genomics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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16
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Kurth D, Elias D, Rasuk MC, Contreras M, Farías ME. Carbon fixation and rhodopsin systems in microbial mats from hypersaline lakes Brava and Tebenquiche, Salar de Atacama, Chile. PLoS One 2021; 16:e0246656. [PMID: 33561170 PMCID: PMC7872239 DOI: 10.1371/journal.pone.0246656] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 01/25/2021] [Indexed: 01/08/2023] Open
Abstract
In this work, molecular diversity of two hypersaline microbial mats was compared by Whole Genome Shotgun (WGS) sequencing of environmental DNA from the mats. Brava and Tebenquiche are lakes in the Salar de Atacama, Chile, where microbial communities are growing in extreme conditions, including high salinity, high solar irradiance, and high levels of toxic metals and metaloids. Evaporation creates hypersaline conditions in these lakes and mineral precipitation is a characteristic geomicrobiological feature of these benthic ecosystems. The mat from Brava was more rich and diverse, with a higher number of different taxa and with species more evenly distributed. At the phylum level, Proteobacteria, Cyanobacteria, Chloroflexi, Bacteroidetes and Firmicutes were the most abundant, including ~75% of total sequences. At the genus level, the most abundant sequences were affilitated to anoxygenic phototropic and cyanobacterial genera. In Tebenquiche mats, Proteobacteria and Bacteroidetes covered ~70% of the sequences, and 13% of the sequences were affiliated to Salinibacter genus, thus addressing the lower diversity. Regardless of the differences at the taxonomic level, functionally the two mats were similar. Thus, similar roles could be fulfilled by different organisms. Carbon fixation through the Wood-Ljungdahl pathway was well represented in these datasets, and also in other mats from Andean lakes. In spite of presenting less taxonomic diversity, Tebenquiche mats showed increased abundance and variety of rhodopsin genes. Comparison with other metagenomes allowed identifying xantorhodopsins as hallmark genes not only from Brava and Tebenquiche mats, but also for other mats developing at high altitudes in similar environmental conditions.
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Affiliation(s)
- Daniel Kurth
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina
| | - Dario Elias
- Facultad de Ingeniería, Universidad Nacional de Entre Ríos, Oro Verde, Entre Ríos, Argentina
| | - María Cecilia Rasuk
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina
| | | | - María Eugenia Farías
- Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA), Planta Piloto de Procesos Industriales Microbiológicos (PROIMI), CCT, CONICET, Tucumán, Argentina
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Comparative genomics reveals new functional insights in uncultured MAST species. ISME JOURNAL 2021; 15:1767-1781. [PMID: 33452482 PMCID: PMC8163842 DOI: 10.1038/s41396-020-00885-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 12/03/2020] [Accepted: 12/14/2020] [Indexed: 02/06/2023]
Abstract
Heterotrophic lineages of stramenopiles exhibit enormous diversity in morphology, lifestyle, and habitat. Among them, the marine stramenopiles (MASTs) represent numerous independent lineages that are only known from environmental sequences retrieved from marine samples. The core energy metabolism characterizing these unicellular eukaryotes is poorly understood. Here, we used single-cell genomics to retrieve, annotate, and compare the genomes of 15 MAST species, obtained by coassembling sequences from 140 individual cells sampled from the marine surface plankton. Functional annotations from their gene repertoires are compatible with all of them being phagocytotic. The unique presence of rhodopsin genes in MAST species, together with their widespread expression in oceanic waters, supports the idea that MASTs may be capable of using sunlight to thrive in the photic ocean. Additional subsets of genes used in phagocytosis, such as proton pumps for vacuole acidification and peptidases for prey digestion, did not reveal particular trends in MAST genomes as compared with nonphagocytotic stramenopiles, except a larger presence and diversity of V-PPase genes. Our analysis reflects the complexity of phagocytosis machinery in microbial eukaryotes, which contrasts with the well-defined set of genes for photosynthesis. These new genomic data provide the essential framework to study ecophysiology of uncultured species and to gain better understanding of the function of rhodopsins and related carotenoids in stramenopiles.
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18
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Moniruzzaman M, Martinez-Gutierrez CA, Weinheimer AR, Aylward FO. Dynamic genome evolution and complex virocell metabolism of globally-distributed giant viruses. Nat Commun 2020; 11:1710. [PMID: 32249765 PMCID: PMC7136201 DOI: 10.1038/s41467-020-15507-2] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/09/2020] [Indexed: 01/11/2023] Open
Abstract
The discovery of eukaryotic giant viruses has transformed our understanding of the limits of viral complexity, but the extent of their encoded metabolic diversity remains unclear. Here we generate 501 metagenome-assembled genomes of Nucleo-Cytoplasmic Large DNA Viruses (NCLDV) from environments around the globe, and analyze their encoded functional capacity. We report a remarkable diversity of metabolic genes in widespread giant viruses, including many involved in nutrient uptake, light harvesting, and nitrogen metabolism. Surprisingly, numerous NCLDV encode the components of glycolysis and the TCA cycle, suggesting that they can re-program fundamental aspects of their host's central carbon metabolism. Our phylogenetic analysis of NCLDV metabolic genes and their cellular homologs reveals distinct clustering of viral sequences into divergent clades, indicating that these genes are virus-specific and were acquired in the distant past. Overall our findings reveal that giant viruses encode complex metabolic capabilities with evolutionary histories largely independent of cellular life, strongly implicating them as important drivers of global biogeochemical cycles.
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Affiliation(s)
| | | | - Alaina R Weinheimer
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Frank O Aylward
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA.
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19
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Tarlachkov SV, Shevchuk TV, Montero-Calasanz MDC, Starodumova IP. Diversity of rhodopsins in cultivated bacteria of the family Geodermatophilaceae associated with non-aquatic environments. Bioinformatics 2020; 36:1668-1672. [PMID: 31711117 DOI: 10.1093/bioinformatics/btz840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/30/2019] [Accepted: 11/10/2019] [Indexed: 12/25/2022] Open
Abstract
MOTIVATION A small amount of research is focused on investigation of rhodopsins in cultivated bacteria isolated from non-aquatic environments. Furthermore, the abundance of these proteins in strains from hot and arid habitats was not reported previously. Since there is an insignificant amount of such isolates, the enigmatic role of the rhodopsins in dry ecological niches is still poorly understood. The members of the family Geodermatophilaceae could be used as interesting objects to search for new rhodopsin genes that will provide novel insights into versatility and importance of these proteins in non-aquatic conditions. RESULTS This is the first report of the abundance of different rhodopsins in cultivated bacteria isolated from hot and arid ecological niches. A total of 31 rhodopsin genes were identified in 51 analyzed genomes of strains belonging to the family Geodermatophilaceae. Overall, 88% of the strains harbouring rhodopsins are isolated from non-aquatic environments. It was found that 82% of strains belonging to the genus Geodermatophilus have at least one gene as compared to 38% of strains of other genera which contain rhodopsins. Analysis of key amino acids revealed two types of the studied proteins: DTE type (putative proton pump) and NDQ type (putative sodium pump). Proton pumps were divided into two subtypes (DTEW and DTEF) according to phylogenetic analysis and the presence of highly conserved tryptophan or phenylalanine at position 182. Among all studied rhodopsins DTEF subtype is the most unique one, identified only in this family. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Sergey V Tarlachkov
- All-Russian Collection of Microorganisms, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, FRC Pushchino Scientific Center for Biological Research.,Department of Plant Molecular Biology and Biotechnology, Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290, Russia
| | - Taras V Shevchuk
- Department of Plant Molecular Biology and Biotechnology, Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino 142290, Russia
| | - Maria Del Carmen Montero-Calasanz
- Plant and Microbial Biology Research Group, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Irina P Starodumova
- All-Russian Collection of Microorganisms, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, FRC Pushchino Scientific Center for Biological Research
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20
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Pereira O, Hochart C, Auguet JC, Debroas D, Galand PE. Genomic ecology of Marine Group II, the most common marine planktonic Archaea across the surface ocean. Microbiologyopen 2019; 8:e00852. [PMID: 31264806 PMCID: PMC6741140 DOI: 10.1002/mbo3.852] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/08/2019] [Accepted: 04/08/2019] [Indexed: 01/22/2023] Open
Abstract
Planktonic Archaea have been detected in all the world's oceans and are found from surface waters to the deep sea. The two most common Archaea phyla are Thaumarchaeota and Euryarchaeota. Euryarchaeota are generally more common in surface waters, but very little is known about their ecology and their potential metabolisms. In this study, we explore the genomic ecology of the Marine Group II (MGII), the main marine planktonic Euryarchaeota, and test if it is composed of different ecologically relevant units. We re‐analyzed Tara Oceans metagenomes from the photic layer and the deep ocean by annotating sequences against a custom MGII database and by mapping gene co‐occurrences. Our data provide a global view of the distribution of Euryarchaeota, and more specifically of MGII subgroups, and reveal their association to a number of gene‐coding sequences. In particular, we show that MGII proteorhodopsins were detected in both the surface and the deep chlorophyll maximum layer and that different clusters of these light harvesting proteins were present. Our approach helped describing the set of genes found together with specific MGII subgroups. We could thus define genomic environments that could theoretically describe ecologically meaningful units and the ecological niche that they occupy.
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Affiliation(s)
- Olivier Pereira
- Sorbonne Université, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques (LECOB), Observatoire Océanologique de Banyuls, Banyuls sur Mer, France
| | - Corentin Hochart
- Laboratoire Microorganismes: Génome et Environnement, UMR 6023, CNRS - Université Blaise Pascal, Aubière, France
| | - Jean Christophe Auguet
- Marine Biodiversity, Exploitation and Conservation (MARBEC), Université de Montpellier, CNRS, IFREMER, Montpellier, France
| | - Didier Debroas
- Laboratoire Microorganismes: Génome et Environnement, UMR 6023, CNRS - Université Blaise Pascal, Aubière, France
| | - Pierre E Galand
- Sorbonne Université, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques (LECOB), Observatoire Océanologique de Banyuls, Banyuls sur Mer, France
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Mukherjee S, Hegemann P, Broser M. Enzymerhodopsins: novel photoregulated catalysts for optogenetics. Curr Opin Struct Biol 2019; 57:118-126. [PMID: 30954887 DOI: 10.1016/j.sbi.2019.02.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 02/03/2019] [Accepted: 02/06/2019] [Indexed: 12/22/2022]
Abstract
Enzymerhodopsins are a recently discovered class of natural rhodopsin-based photoreceptors with light-regulated enzyme activity. Currently, three different types of these fusion proteins with an N-terminal type-1 rhodopsin and a C-terminal enzyme domain have been identified, but their physiological relevance is mostly unknown. Among these, histidine kinase rhodopsins (HKR) are photo-regulated two-component-like signaling systems that trigger a phosphorylation cascade, whereas rhodopsin phosphodiesterase (RhoPDE) or rhodopsin guanylyl cyclase (RhGC) show either light-activated hydrolysis or production of cyclic nucleotides. RhGC, the best characterized enzymerhodopsin, is involved in the phototaxis of fungal zoospores and allows for optically controlled production of cyclic nucleotides in different cell-types. These photoreceptors have great optogenetic potential and possess several advantages over the hitherto existing tools to manipulate cyclic-nucleotide dynamics in living cells.
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Affiliation(s)
- Shatanik Mukherjee
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Germany.
| | - Peter Hegemann
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Germany
| | - Matthias Broser
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Germany.
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Tully BJ. Metabolic diversity within the globally abundant Marine Group II Euryarchaea offers insight into ecological patterns. Nat Commun 2019; 10:271. [PMID: 30655514 PMCID: PMC6336850 DOI: 10.1038/s41467-018-07840-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 12/03/2018] [Indexed: 11/08/2022] Open
Abstract
Despite their discovery over 25 years ago, the Marine Group II Euryarchaea (MGII) remain a difficult group of organisms to study, lacking cultured isolates and genome references. The MGII have been identified in marine samples from around the world, and evidence supports a photoheterotrophic lifestyle combining phototrophy via proteorhodopsins with the remineralization of high molecular weight organic matter. Divided between two clades, the MGII have distinct ecological patterns that are not understood based on the limited number of available genomes. Here, I present a comparative genomic analysis of 250 MGII genomes, providing a comprehensive investigation of these mesophilic archaea. This analysis identifies 17 distinct subclades including nine subclades that previously lacked reference genomes. The metabolic potential and distribution of the MGII genera reveals distinct roles in the environment, identifying algal-saccharide-degrading coastal subclades, protein-degrading oligotrophic surface ocean subclades, and mesopelagic subclades lacking proteorhodopsins, common in all other subclades.
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Affiliation(s)
- Benjamin J Tully
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
- Center for Dark Energy Biosphere Investigations, University of Southern California, Los Angeles, CA, 90089, USA.
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Sieradzki ET, Fuhrman JA, Rivero-Calle S, Gómez-Consarnau L. Proteorhodopsins dominate the expression of phototrophic mechanisms in seasonal and dynamic marine picoplankton communities. PeerJ 2018; 6:e5798. [PMID: 30370186 PMCID: PMC6202958 DOI: 10.7717/peerj.5798] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/20/2018] [Indexed: 12/13/2022] Open
Abstract
The most abundant and ubiquitous microbes in the surface ocean use light as an energy source, capturing it via complex chlorophyll-based photosystems or simple retinal-based rhodopsins. Studies in various ocean regimes compared the abundance of these mechanisms, but few investigated their expression. Here we present the first full seasonal study of abundance and expression of light-harvesting mechanisms (proteorhodopsin, PR; aerobic anoxygenic photosynthesis, AAnP; and oxygenic photosynthesis, PSI) from deep-sequenced metagenomes and metatranscriptomes of marine picoplankton (<1 µm) at three coastal stations of the San Pedro Channel in the Pacific Ocean. We show that, regardless of season or sampling location, the most common phototrophic mechanism in metagenomes of this dynamic region was PR (present in 65–104% of the genomes as estimated by single-copy recA), followed by PSI (5–104%) and AAnP (5–32%). Furthermore, the normalized expression (RNA to DNA ratio) of PR genes was higher than that of oxygenic photosynthesis (average ± standard deviation 26.2 ± 8.4 vs. 11 ± 9.7), and the expression of the AAnP marker gene was significantly lower than both mechanisms (0.013 ± 0.02). We demonstrate that PR expression was dominated by the SAR11-cluster year-round, followed by other Alphaproteobacteria, unknown-environmental clusters and Gammaproteobacteria. This highly dynamic system further allowed us to identify a trend for PR spectral tuning, in which blue-absorbing PR genes dominate in areas with low chlorophyll-a concentrations (<0.25 µgL−1). This suggests that PR phototrophy is not an accessory function but instead a central mechanism that can regulate photoheterotrophic population dynamics.
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Affiliation(s)
- Ella T Sieradzki
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States of America
| | - Jed A Fuhrman
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States of America
| | - Sara Rivero-Calle
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States of America
| | - Laura Gómez-Consarnau
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States of America
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Parallel Evolution of Genome Streamlining and Cellular Bioenergetics across the Marine Radiation of a Bacterial Phylum. mBio 2018; 9:mBio.01089-18. [PMID: 30228235 PMCID: PMC6143742 DOI: 10.1128/mbio.01089-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Understanding long-term patterns of microbial evolution is critical to advancing our knowledge of past and present role microbial life in driving global biogeochemical cycles. Historically, it has been challenging to study the evolution of environmental microbes due to difficulties in obtaining genome sequences from lineages that could not be cultivated, but recent advances in metagenomics and single-cell genomics have begun to obviate many of these hurdles. Here we present an evolutionary genomic analysis of the Marinimicrobia, a diverse bacterial group that is abundant in the global ocean. We demonstrate that distantly related Marinimicrobia species that reside in similar habitats have converged to assume similar genome architectures and cellular bioenergetics, suggesting that common factors shape the evolution of a broad array of marine lineages. These findings broaden our understanding of the evolutionary forces that have given rise to microbial life in the contemporary ocean. Diverse bacterial and archaeal lineages drive biogeochemical cycles in the global ocean, but the evolutionary processes that have shaped their genomic properties and physiological capabilities remain obscure. Here we track the genome evolution of the globally abundant marine bacterial phylum Marinimicrobia across its diversification into modern marine environments and demonstrate that extant lineages are partitioned between epipelagic and mesopelagic habitats. Moreover, we show that these habitat preferences are associated with fundamental differences in genomic organization, cellular bioenergetics, and metabolic modalities. Multiple lineages present in epipelagic niches independently acquired genes necessary for phototrophy and environmental stress mitigation, and their genomes convergently evolved key features associated with genome streamlining. In contrast, lineages residing in mesopelagic waters independently acquired nitrate respiratory machinery and a variety of cytochromes, consistent with the use of alternative terminal electron acceptors in oxygen minimum zones (OMZs). Further, while epipelagic clades have retained an ancestral Na+-pumping respiratory complex, mesopelagic lineages have largely replaced this complex with canonical H+-pumping respiratory complex I, potentially due to the increased efficiency of the latter together with the presence of the more energy-limiting environments deep in the ocean’s interior. These parallel evolutionary trends indicate that key features of genomic streamlining and cellular bioenergetics have occurred repeatedly and congruently in disparate clades and underscore the importance of environmental conditions and nutrient dynamics in driving the evolution of diverse bacterioplankton lineages in similar ways throughout the global ocean.
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Cho BC, Hardies SC, Jang GI, Hwang CY. Complete genome of streamlined marine actinobacterium Pontimonas salivibrio strain CL-TW6 T adapted to coastal planktonic lifestyle. BMC Genomics 2018; 19:625. [PMID: 30134835 PMCID: PMC6106888 DOI: 10.1186/s12864-018-5019-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 08/14/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Pontimonas salivibrio strain CL-TW6T (=KCCM 90105 = JCM18206) was characterized as the type strain of a new genus within the Actinobacterial family Microbacteriaceae. It was isolated from a coastal marine environment in which members of Microbactericeae have not been previously characterized. RESULTS The genome of P. salivibrio CL-TW6T was a single chromosome of 1,760,810 bp. Genomes of this small size are typically found in bacteria growing slowly in oligotrophic zones and said to be streamlined. Phylogenetic analysis showed it to represent a lineage originating in the Microbacteriaceae radiation occurring before the snowball Earth glaciations, and to have a closer relationship with some streamlined bacteria known through metagenomic data. Several genomic characteristics typical of streamlined bacteria are found: %G + C is lower than non-streamlined members of the phylum; there are a minimal number of rRNA and tRNA genes, fewer paralogs in most gene families, and only two sigma factors; there is a noticeable absence of some nonessential metabolic pathways, including polyketide synthesis and catabolism of some amino acids. There was no indication of any phage genes or plasmids, however, a system of active insertion elements was present. P. salivibrio appears to be unusual in having polyrhamnose-based cell wall oligosaccharides instead of mycolic acid or teichoic acid-based oligosaccharides. Oddly, it conducts sulfate assimilation apparently for sulfating cell wall components, but not for synthesizing amino acids. One gene family it has more of, rather than fewer of, are toxin/antitoxin systems, which are thought to down-regulate growth during nutrient deprivation or other stressful conditions. CONCLUSIONS Because of the relatively small number of paralogs and its relationship to the heavily characterized Mycobacterium tuberculosis, we were able to heavily annotate the genome of P. salivibrio CL-TW6T. Its streamlined status and relationship to streamlined metagenomic constructs makes it an important reference genome for study of the streamlining concept. The final evolutionary trajectory of CL-TW6 T was to adapt to growth in a non-oligotrophic coastal zone. To understand that adaptive process, we give a thorough accounting of gene content, contrasting with both oligotrophic streamlined bacteria and large genome bacteria, and distinguishing between genes derived by vertical and horizontal descent.
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Affiliation(s)
- Byung Cheol Cho
- Microbial Oceanography Laboratory, School of Earth and Environmental Sciences and Research Institute of Oceanography, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Stephen C. Hardies
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio, TX USA
| | - Gwang Il Jang
- Microbial Oceanography Laboratory, School of Earth and Environmental Sciences and Research Institute of Oceanography, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
- Division of Life Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
| | - Chung Yeon Hwang
- Division of Life Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
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Haro-Moreno JM, López-Pérez M, de la Torre JR, Picazo A, Camacho A, Rodriguez-Valera F. Fine metagenomic profile of the Mediterranean stratified and mixed water columns revealed by assembly and recruitment. MICROBIOME 2018; 6:128. [PMID: 29991350 PMCID: PMC6040077 DOI: 10.1186/s40168-018-0513-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/02/2018] [Indexed: 05/07/2023]
Abstract
BACKGROUND The photic zone of aquatic habitats is subjected to strong physicochemical gradients. To analyze the fine-scale variations in the marine microbiome, we collected seven samples from a single offshore location in the Mediterranean at 15 m depth intervals during a period of strong stratification, as well as two more samples during the winter when the photic water column was mixed. We were able to recover 94 new metagenome-assembled genomes (MAGs) from these metagenomes and examine the distribution of key marine microbes within the photic zone using metagenomic recruitment. RESULTS Our results showed significant differences in the microbial composition of different layers within the stratified photic water column. The majority of microorganisms were confined to discreet horizontal layers of no more than 30 m (stenobathic). Only a few such as members of the SAR11 clade appeared at all depths (eurybathic). During the winter mixing period, only some groups of bloomers such as Pseudomonas were favored. Although most microbes appeared in both seasons, some groups like the SAR116 clade and some Bacteroidetes and Verrucomicrobia seemed to disappear during the mixing period. Furthermore, we found that some microbes previously considered seasonal (e.g., Archaea or Actinobacteria) were living in deeper layers within the photic zone during the stratification period. A strong depth-related specialization was detected, not only at the taxonomic level but also at the functional level, even within the different clades, for the manipulation and uptake of specific polysaccharides. Rhodopsin sequences (green or blue) also showed narrow depth distributions that correlated with the taxonomy of the microbe in which they were found but not with depth. CONCLUSIONS Although limited to a single location in the Mediterranean, this study has profound implications for our understanding of how marine microbial communities vary with depth within the photic zone when stratified. Our results highlight the importance of collecting samples at different depths in the water column when comparing seasonal variations and have important ramifications for global marine studies that most often take samples from only one single depth. Furthermore, our perspective and approaches (metagenomic assembly and recruitment) are broadly applicable to other metagenomic studies.
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Affiliation(s)
- Jose M Haro-Moreno
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, Apartado 18, San Juan de Alicante, 03550, Alicante, Spain
| | - Mario López-Pérez
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, Apartado 18, San Juan de Alicante, 03550, Alicante, Spain
| | - José R de la Torre
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, USA
| | - Antonio Picazo
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Burjassot, E-46100, Valencia, Spain
| | - Antonio Camacho
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Burjassot, E-46100, Valencia, Spain
| | - Francisco Rodriguez-Valera
- Evolutionary Genomics Group, División de Microbiología, Universidad Miguel Hernández, Apartado 18, San Juan de Alicante, 03550, Alicante, Spain.
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Olson DK, Yoshizawa S, Boeuf D, Iwasaki W, DeLong EF. Proteorhodopsin variability and distribution in the North Pacific Subtropical Gyre. ISME JOURNAL 2018; 12:1047-1060. [PMID: 29476140 PMCID: PMC5864233 DOI: 10.1038/s41396-018-0074-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/21/2017] [Accepted: 12/05/2017] [Indexed: 11/17/2022]
Abstract
Proteorhodopsin is a light-activated retinal-containing proton pump found in many marine bacteria. These photoproteins are globally distributed in the ocean’s photic zone and are capable of generating a proton motive force across the cell membrane. We investigated the phylogenetic diversity, distribution, and abundance of proteorhodopsin encoding genes in free-living bacterioplankton in the North Pacific Subtropical Gyre, leveraging a gene catalog derived from metagenomic samples from the ocean’s surface to 1000 m depth. Proteorhodopsin genes were identified at all depths sampled, but were most abundant at depths shallower than 200 m. The majority of proteorhodopsin gene sequences (60.9%) belonged to members of the SAR11 lineage, with remaining sequences distributed among other diverse taxa. We observed variations in the conserved residues involved in ion pumping and spectral tuning, and biochemically confirmed four different proton pumping proteorhodopsin motifs, including one unique to deep-water SAR11. We also identified a new group of putative proteorhodopsins having unknown function. Our results reveal a broad organismal and unexpected depth distribution for different proteorhodopsin types, as well as substantial within-taxon variability. These data provide a framework for exploring the ecological relevance of proteorhodopsins and their spatiotemporal variation and function in heterotrophic bacteria in the open ocean.
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Affiliation(s)
- Daniel K Olson
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography, University of Hawaii, Honolulu, HI, 96822, USA
| | - Susumu Yoshizawa
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, 277-8564, Japan
| | - Dominique Boeuf
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography, University of Hawaii, Honolulu, HI, 96822, USA
| | - Wataru Iwasaki
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, 277-8564, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Edward F DeLong
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography, University of Hawaii, Honolulu, HI, 96822, USA.
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Tahon G, Willems A. Isolation and characterization of aerobic anoxygenic phototrophs from exposed soils from the Sør Rondane Mountains, East Antarctica. Syst Appl Microbiol 2017; 40:357-369. [DOI: 10.1016/j.syapm.2017.05.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 12/24/2022]
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Tahon G, Tytgat B, Willems A. Diversity of Phototrophic Genes Suggests Multiple Bacteria May Be Able to Exploit Sunlight in Exposed Soils from the Sør Rondane Mountains, East Antarctica. Front Microbiol 2016; 7:2026. [PMID: 28066352 PMCID: PMC5165242 DOI: 10.3389/fmicb.2016.02026] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 12/02/2016] [Indexed: 01/10/2023] Open
Abstract
Microbial life in exposed terrestrial surface layers in continental Antarctica is faced with extreme environmental conditions, including scarcity of organic matter. Bacteria in these exposed settings can therefore be expected to use alternative energy sources such as solar energy, abundant during the austral summer. Using Illumina MiSeq sequencing, we assessed the diversity and abundance of four conserved protein encoding genes involved in different key steps of light-harvesting pathways dependent on (bacterio)chlorophyll (pufM, bchL/chlL, and bchX genes) and rhodopsins (actinorhodopsin genes), in exposed soils from the Sør Rondane Mountains, East Antarctica. Analysis of pufM genes, encoding a subunit of the type 2 photochemical reaction center found in anoxygenic phototrophic bacteria, revealed a broad diversity, dominated by Roseobacter- and Loktanella-like sequences. The bchL and chlL, involved in (bacterio)chlorophyll synthesis, on the other hand, showed a high relative abundance of either cyanobacterial or green algal trebouxiophyceael chlL reads, depending on the sample, while most bchX sequences belonged mostly to previously unidentified phylotypes. Rhodopsin-containing phototrophic bacteria could not be detected in the samples. Our results, while suggesting that Cyanobacteria and green algae are the main phototrophic groups, show that light-harvesting bacteria are nevertheless very diverse in microbial communities in Antarctic soils.
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Affiliation(s)
- Guillaume Tahon
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University Ghent, Belgium
| | - Bjorn Tytgat
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University Ghent, Belgium
| | - Anne Willems
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University Ghent, Belgium
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Geographic Impact on Genomic Divergence as Revealed by Comparison of Nine Citromicrobial Genomes. Appl Environ Microbiol 2016; 82:7205-7216. [PMID: 27736788 DOI: 10.1128/aem.02495-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/03/2016] [Indexed: 11/20/2022] Open
Abstract
Aerobic anoxygenic phototrophic bacteria (AAPB) are thought to be important players in oceanic carbon and energy cycling in the euphotic zone of the ocean. The genus Citromicrobium, widely found in oligotrophic oceans, is a member of marine alphaproteobacterial AAPB. Nine Citromicrobium strains isolated from the South China Sea, the Mediterranean Sea, or the tropical South Atlantic Ocean were found to harbor identical 16S rRNA sequences. The sequencing of their genomes revealed high synteny in major regions. Nine genetic islands (GIs) involved mainly in type IV secretion systems, flagellar biosynthesis, prophage, and integrative conjugative elements, were identified by a fine-scale comparative genomics analysis. These GIs played significant roles in genomic evolution and divergence. Interestingly, the coexistence of two different photosynthetic gene clusters (PGCs) was not only found in the analyzed genomes but also confirmed, for the first time, to our knowledge, in environmental samples. The prevalence of the coexistence of two different PGCs may suggest an adaptation mechanism for Citromicrobium members to survive in the oceans. Comparison of genomic characteristics (e.g., GIs, average nucleotide identity [ANI], single-nucleotide polymorphisms [SNPs], and phylogeny) revealed that strains within a marine region shared a similar evolutionary history that was distinct from that of strains isolated from other regions (South China Sea versus Mediterranean Sea). Geographic differences are partly responsible for driving the observed genomic divergences and allow microbes to evolve through local adaptation. Three Citromicrobium strains isolated from the Mediterranean Sea diverged millions of years ago from other strains and evolved into a novel group. IMPORTANCE Aerobic anoxygenic phototrophic bacteria are a widespread functional group in the upper ocean, and their abundance could be up to 15% of the total heterotrophic bacteria. To date, a great number of studies display AAPB biogeographic distribution patterns in the ocean; however, little is understood about the geographic isolation impact on the genome divergence of marine AAPB. In this study, we compare nine Citromicrobium genomes of strains that have identical 16S rRNA sequences but different ocean origins. Our results reveal that strains isolated from the same marine region share a similar evolutionary history that is distinct from that of strains isolated from other regions. These Citromicrobium strains diverged millions of years ago. In addition, the coexistence of two different PGCs is prevalent in the analyzed genomes and in environmental samples.
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Marine Bacterial and Archaeal Ion-Pumping Rhodopsins: Genetic Diversity, Physiology, and Ecology. Microbiol Mol Biol Rev 2016; 80:929-54. [PMID: 27630250 DOI: 10.1128/mmbr.00003-16] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The recognition of a new family of rhodopsins in marine planktonic bacteria, proton-pumping proteorhodopsin, expanded the known phylogenetic range, environmental distribution, and sequence diversity of retinylidene photoproteins. At the time of this discovery, microbial ion-pumping rhodopsins were known solely in haloarchaea inhabiting extreme hypersaline environments. Shortly thereafter, proteorhodopsins and other light-activated energy-generating rhodopsins were recognized to be widespread among marine bacteria. The ubiquity of marine rhodopsin photosystems now challenges prior understanding of the nature and contributions of "heterotrophic" bacteria to biogeochemical carbon cycling and energy fluxes. Subsequent investigations have focused on the biophysics and biochemistry of these novel microbial rhodopsins, their distribution across the tree of life, evolutionary trajectories, and functional expression in nature. Later discoveries included the identification of proteorhodopsin genes in all three domains of life, the spectral tuning of rhodopsin variants to wavelengths prevailing in the sea, variable light-activated ion-pumping specificities among bacterial rhodopsin variants, and the widespread lateral gene transfer of biosynthetic genes for bacterial rhodopsins and their associated photopigments. Heterologous expression experiments with marine rhodopsin genes (and associated retinal chromophore genes) provided early evidence that light energy harvested by rhodopsins could be harnessed to provide biochemical energy. Importantly, some studies with native marine bacteria show that rhodopsin-containing bacteria use light to enhance growth or promote survival during starvation. We infer from the distribution of rhodopsin genes in diverse genomic contexts that different marine bacteria probably use rhodopsins to support light-dependent fitness strategies somewhere between these two extremes.
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32
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Porter ML. Beyond the Eye: Molecular Evolution of Extraocular Photoreception. Integr Comp Biol 2016; 56:842-852. [DOI: 10.1093/icb/icw052] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Maresca JA, Keffer JL, Miller KJ. Biochemical Analysis of Microbial Rhodopsins. ACTA ACUST UNITED AC 2016; 41:1F.4.1-1F.4.18. [PMID: 27153387 DOI: 10.1002/cpmc.5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Ion-pumping rhodopsins transfer ions across the microbial cell membrane in a light-dependent fashion. As the rate of biochemical characterization of microbial rhodopsins begins to catch up to the rate of microbial rhodopsin identification in environmental and genomic sequence data sets, in vitro analysis of their light-absorbing properties and in vivo analysis of ion pumping will remain critical to characterizing these proteins. As we learn more about the variety of physiological roles performed by microbial rhodopsins in different cell types and environments, observing the localization patterns of the rhodopsins and/or quantifying the number of rhodopsin-bearing cells in natural environments will become more important. Here, we provide protocols for purification of rhodopsin-containing membranes, detection of ion pumping, and observation of functional rhodopsins in laboratory and environmental samples using total internal reflection fluorescence microscopy. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Julia A Maresca
- University of Delaware, Department of Civil and Environmental Engineering, Newark, Delaware
| | - Jessica L Keffer
- University of Delaware, Department of Civil and Environmental Engineering, Newark, Delaware
| | - Kelsey J Miller
- University of Delaware, Department of Biological Sciences, Newark, Delaware
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34
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Shalaeva DN, Galperin MY, Mulkidjanian AY. Eukaryotic G protein-coupled receptors as descendants of prokaryotic sodium-translocating rhodopsins. Biol Direct 2015; 10:63. [PMID: 26472483 PMCID: PMC4608122 DOI: 10.1186/s13062-015-0091-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/12/2015] [Indexed: 12/20/2022] Open
Abstract
Abstract Microbial rhodopsins and G-protein coupled receptors (GPCRs, which include animal rhodopsins) are two distinct (super) families of heptahelical (7TM) membrane proteins that share obvious structural similarities but no significant sequence similarity. Comparison of the recently solved high-resolution structures of the sodium-translocating bacterial rhodopsin and various Na+-binding GPCRs revealed striking similarity of their sodium-binding sites. This similarity allowed us to construct a structure-guided sequence alignment for the two (super)families, which highlighted their evolutionary relatedness. Our analysis supports a common underlying molecular mechanism for both families that involves a highly conserved aromatic residue playing a pivotal role in rotation of the 6th transmembrane helix. Reviewers This article was reviewed by Oded Beja, G. P. S. Raghava and L. Aravind. Electronic supplementary material The online version of this article (doi:10.1186/s13062-015-0091-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daria N Shalaeva
- School of Physics, Osnabrueck University, 49069, Osnabrueck, Germany. .,School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia.
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA.
| | - Armen Y Mulkidjanian
- School of Physics, Osnabrueck University, 49069, Osnabrueck, Germany. .,School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia. .,A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
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