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Aanderud ZT, Bahr J, Robinson DM, Belnap J, Campbell TP, Gill RA, McMillian B, St. Clair S. The Burning of Biocrusts Facilitates the Emergence of a Bare Soil Community of Poorly-Connected Chemoheterotrophic Bacteria With Depressed Ecosystem Services. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00467] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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52
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Anoxygenic Phototrophs Span Geochemical Gradients and Diverse Morphologies in Terrestrial Geothermal Springs. mSystems 2019; 4:4/6/e00498-19. [PMID: 31690593 PMCID: PMC6832021 DOI: 10.1128/msystems.00498-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Extant anoxygenic phototrophs are taxonomically, physiologically, and metabolically diverse and include examples from all seven bacterial phyla with characterized phototrophic members. pH, temperature, and sulfide are known to constrain phototrophs, but how these factors dictate the distribution and activity of specific taxa of anoxygenic phototrophs has not been reported. Here, we hypothesized that within the known limits of pH, temperature, and sulfide, the distribution, abundance, and activity of specific anoxygenic phototrophic taxa would vary due to key differences in the physiology of these organisms. To test this hypothesis, we examined the distribution, abundance, and potential activity of anoxygenic phototrophs in filaments, microbial mats, and sediments across geochemical gradients in geothermal features of Yellowstone National Park, which ranged in pH from 2.2 to 9.4 and in temperature from 31.5°C to 71.0°C. Indeed, our data indicate putative aerobic anoxygenic phototrophs within the Proteobacteria are more abundant at lower pH and lower temperature, while phototrophic Chloroflexi are prevalent in circumneutral to alkaline springs. In contrast to previous studies, our data suggest sulfide is not a key determinant of anoxygenic phototrophic taxa. Finally, our data underscore a role for photoheterotrophy (or photomixotrophy) across geochemical gradients in terrestrial geothermal ecosystems.IMPORTANCE There is a long and rich history of literature on phototrophs in terrestrial geothermal springs. These studies have revealed sulfide, pH, and temperature are the main constraints on phototrophy. However, the taxonomic and physiological diversity of anoxygenic phototrophs suggests that, within these constraints, specific geochemical parameters determine the distribution and activity of individual anoxygenic phototrophic taxa. Here, we report the recovery of sequences affiliated with characterized anoxygenic phototrophs in sites that range in pH from 2 to 9 and in temperature from 31°C to 71°C. Transcript abundance indicates anoxygenic phototrophs are active across this temperature and pH range. Our data suggest sulfide is not a key determinant of anoxygenic phototrophic taxa and underscore a role for photoheterotrophy in terrestrial geothermal ecosystems. These data provide the framework for high-resolution sequencing and in situ activity approaches to characterize the physiology of specific anoxygenic phototrophic taxa across a broad range of temperatures and pH.
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53
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Analysis of the soil microbial communities in Pinus tabulaeformis Carr. and Bupleurum chinense plantations of the Xiaolongshan Mountain region, Gansu Province, China. ECOL INFORM 2019. [DOI: 10.1016/j.ecoinf.2019.100981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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54
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Thomas SC, Tamadonfar KO, Seymour CO, Lai D, Dodsworth JA, Murugapiran SK, Eloe-Fadrosh EA, Dijkstra P, Hedlund BP. Position-Specific Metabolic Probing and Metagenomics of Microbial Communities Reveal Conserved Central Carbon Metabolic Network Activities at High Temperatures. Front Microbiol 2019; 10:1427. [PMID: 31333598 PMCID: PMC6624737 DOI: 10.3389/fmicb.2019.01427] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 06/05/2019] [Indexed: 12/02/2022] Open
Abstract
Temperature is a primary driver of microbial community composition and taxonomic diversity; however, it is unclear to what extent temperature affects characteristics of central carbon metabolic pathways (CCMPs) at the community level. In this study, 16S rRNA gene amplicon and metagenome sequencing were combined with 13C-labeled metabolite probing of the CCMPs to assess community carbon metabolism along a temperature gradient (60–95°C) in Great Boiling Spring, NV. 16S rRNA gene amplicon diversity was inversely proportional to temperature, and Archaea were dominant at higher temperatures. KO richness and diversity were also inversely proportional to temperature, yet CCMP genes were similarly represented across the temperature gradient and many individual metagenome-assembled genomes had complete pathways. In contrast, genes encoding cellulosomes and many genes involved in plant matter degradation and photosynthesis were absent at higher temperatures. In situ13C-CO2 production from labeled isotopomer pairs of glucose, pyruvate, and acetate suggested lower relative oxidative pentose phosphate pathway activity and/or fermentation at 60°C, and a stable or decreased maintenance energy demand at higher temperatures. Catabolism of 13C-labeled citrate, succinate, L-alanine, L-serine, and L-cysteine was observed at 85°C, demonstrating broad heterotrophic activity and confirming functioning of the TCA cycle. Together, these results suggest that temperature-driven losses in biodiversity and gene content in geothermal systems may not alter CCMP function or maintenance energy demands at a community level.
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Affiliation(s)
- Scott C Thomas
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States
| | - Kevin O Tamadonfar
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States
| | - Cale O Seymour
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States
| | - Dengxun Lai
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States
| | - Jeremy A Dodsworth
- Department of Biology, California State University, San Bernardino, CA, United States
| | | | - Emiley A Eloe-Fadrosh
- Department of Energy Joint Genome Institute, Joint Genome Institute, Walnut Creek, CA, United States
| | - Paul Dijkstra
- Department of Biological Sciences, Center of Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States.,Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, NV, United States
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55
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Cardoso DC, Cretoiu MS, Stal LJ, Bolhuis H. Seasonal development of a coastal microbial mat. Sci Rep 2019; 9:9035. [PMID: 31227767 PMCID: PMC6588573 DOI: 10.1038/s41598-019-45490-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/30/2019] [Indexed: 11/08/2022] Open
Abstract
Growth and activity of coastal microbial mats is strongly seasonal. The development of these mats starts in early spring and fully maturate during late summer, where after growth ceases and subsequently the mat deteriorates by erosion and decomposition in winter. Here, the composition of the microbial community of three different mats developing along the tidal gradient of the North Sea beach of the Dutch barrier island Schiermonnikoog was analysed. The 16S ribosomal RNA molecules and the associated gene were sequenced in order to obtain the active (RNA) and resident (DNA) community members, respectively. Proteobacteria, Cyanobacteria, and Bacteroidetes dominated the mats during the whole year but considerable differences among these groups were found along the tidal gradient and seasonally when observed at a finer taxonomic resolution. Richness and diversity increased during the year starting from a pioneering community that is gradually succeeded by a more diverse climax community. The initial pioneers consisted of the cold-adapted photoautotrophic cyanobacterium Nodularia sp. and potential cold adapted members of the alphaproteobacterial Loktanella genus. These pioneers were succeeded by, amongst others, cyanobacteria belonging to the genera Leptolyngbya, Lyngbya, and Phormidium. At the upper littoral (Dune site), which was characterized by an extensive salt marsh vegetation, the mats contained a distinct bacterial community that potentially contribute to or benefit from plant decay. This study reports in detail on the seasonal changes and succession of these coastal microbial mat communities and discusses the potential forces that drive these changes.
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Affiliation(s)
- Daniela Clara Cardoso
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, and Utrecht University, Den Hoorn, The Netherlands
| | - Mariana Silvia Cretoiu
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, and Utrecht University, Den Hoorn, The Netherlands
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, 04544, USA
| | - Lucas J Stal
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, and Utrecht University, Den Hoorn, The Netherlands
- Freshwater and Marine Ecology (IBED-FAME), University of Amsterdam, Amsterdam, The Netherlands
| | - Henk Bolhuis
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, and Utrecht University, Den Hoorn, The Netherlands.
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56
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León-Sobrino C, Ramond JB, Maggs-Kölling G, Cowan DA. Nutrient Acquisition, Rather Than Stress Response Over Diel Cycles, Drives Microbial Transcription in a Hyper-Arid Namib Desert Soil. Front Microbiol 2019; 10:1054. [PMID: 31139170 PMCID: PMC6527771 DOI: 10.3389/fmicb.2019.01054] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/26/2019] [Indexed: 11/13/2022] Open
Abstract
Hot desert surface soils are characterized by extremely low water activities for large parts of any annual cycle. It is widely assumed that microbial processes in such soils are very limited. Here we present the first metatranscriptomic survey of microbial community function in a low water activity hyperarid desert soil. Sequencing of total mRNA revealed a diverse and active community, dominated by Actinobacteria. Metatranscriptomic analysis of samples taken at different times over 3 days indicated that functional diel variations were limited at the whole community level, and mostly affected the eukaryotic subpopulation which was induced during the cooler night hours. High levels of transcription of chemoautotrophic carbon fixation genes contrasted with limited expression of photosynthetic genes, indicating that chemoautotrophy is an important alternative to photosynthesis for carbon cycling in desiccated desert soils. Analysis of the transcriptional levels of key N-cycling genes provided strong evidence that soil nitrate was the dominant nitrogen input source. Transcriptional network analyses and taxon-resolved functional profiling suggested that nutrient acquisition processes, and not diurnal environmental variation, were the main drivers of community activity in hyperarid Namib Desert soil. While we also observed significant levels of expression of common stress response genes, these genes were not dominant hubs in the co-occurrence network.
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Affiliation(s)
- Carlos León-Sobrino
- Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Jean-Baptiste Ramond
- Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | | | - Don A. Cowan
- Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
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57
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Two Chloroflexi classes independently evolved the ability to persist on atmospheric hydrogen and carbon monoxide. ISME JOURNAL 2019; 13:1801-1813. [PMID: 30872805 PMCID: PMC6776052 DOI: 10.1038/s41396-019-0393-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/21/2019] [Accepted: 02/20/2019] [Indexed: 11/29/2022]
Abstract
Most aerobic bacteria exist in dormant states within natural environments. In these states, they endure adverse environmental conditions such as nutrient starvation by decreasing metabolic expenditure and using alternative energy sources. In this study, we investigated the energy sources that support persistence of two aerobic thermophilic strains of the environmentally widespread but understudied phylum Chloroflexi. A transcriptome study revealed that Thermomicrobium roseum (class Chloroflexia) extensively remodels its respiratory chain upon entry into stationary phase due to nutrient limitation. Whereas primary dehydrogenases associated with heterotrophic respiration were downregulated, putative operons encoding enzymes involved in molecular hydrogen (H2), carbon monoxide (CO), and sulfur compound oxidation were significantly upregulated. Gas chromatography and microsensor experiments showed that T. roseum aerobically respires H2 and CO at a range of environmentally relevant concentrations to sub-atmospheric levels. Phylogenetic analysis suggests that the hydrogenases and carbon monoxide dehydrogenases mediating these processes are widely distributed in Chloroflexi genomes and have probably been horizontally acquired on more than one occasion. Consistently, we confirmed that the sporulating isolate Thermogemmatispora sp. T81 (class Ktedonobacteria) also oxidises atmospheric H2 and CO during persistence, though further studies are required to determine if these findings extend to mesophilic strains. This study provides axenic culture evidence that atmospheric CO supports bacterial persistence and reports the third phylum, following Actinobacteria and Acidobacteria, to be experimentally shown to mediate the biogeochemically and ecologically important process of atmospheric H2 oxidation. This adds to the growing body of evidence that atmospheric trace gases are dependable energy sources for bacterial persistence.
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58
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Thiel V, Garcia Costas AM, Fortney NW, Martinez JN, Tank M, Roden EE, Boyd ES, Ward DM, Hanada S, Bryant DA. " Candidatus Thermonerobacter thiotrophicus," A Non-phototrophic Member of the Bacteroidetes/Chlorobi With Dissimilatory Sulfur Metabolism in Hot Spring Mat Communities. Front Microbiol 2019; 9:3159. [PMID: 30687241 PMCID: PMC6338057 DOI: 10.3389/fmicb.2018.03159] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/05/2018] [Indexed: 12/31/2022] Open
Abstract
In this study we present evidence for a novel, thermophilic bacterium with dissimilatory sulfur metabolism, tentatively named “Candidatus Thermonerobacter thiotrophicus,” which is affiliated with the Bacteroides/Ignavibacteria/Chlorobi and which we predict to be a sulfate reducer. Dissimilatory sulfate reduction (DSR) is an important and ancient metabolic process for energy conservation with global importance for geochemical sulfur and carbon cycling. Characterized sulfate-reducing microorganisms (SRM) are found in a limited number of bacterial and archaeal phyla. However, based on highly diverse environmental dsrAB sequences, a variety of uncultivated and unidentified SRM must exist. The recent development of high-throughput sequencing methods allows the phylogenetic identification of some of these uncultured SRM. In this study, we identified a novel putative SRM inhabiting hot spring microbial mats that is a member of the OPB56 clade (“Ca. Kapabacteria”) within the Bacteroidetes/Chlorobi superphylum. Partial genomes for this new organism were retrieved from metagenomes from three different hot springs in Yellowstone National Park, United States, and Japan. Supporting the prediction of a sulfate-reducing metabolism for this organism during period of anoxia, diel metatranscriptomic analyses indicate highest relative transcript levels in situ for all DSR-related genes at night. The presence of terminal oxidases, which are transcribed during the day, further suggests that these organisms might also perform aerobic respiration. The relative phylogenetic proximity to the sulfur-oxidizing, chlorophototrophic Chlorobi further raises new questions about the evolution of dissimilatory sulfur metabolism.
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Affiliation(s)
- Vera Thiel
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Amaya M Garcia Costas
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States.,Department of Biology, Colorado State University-Pueblo, Pueblo, CO, United States
| | - Nathaniel W Fortney
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI, United States
| | - Joval N Martinez
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.,Department of Natural Sciences, University of St. La Salle, Bacolod, Philippines
| | - Marcus Tank
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Eric E Roden
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI, United States
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - David M Ward
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, United States
| | - Satoshi Hanada
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States.,Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States
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59
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The Transcriptional Cycle Is Suited to Daytime N 2 Fixation in the Unicellular Cyanobacterium " Candidatus Atelocyanobacterium thalassa" (UCYN-A). mBio 2019; 10:mBio.02495-18. [PMID: 30602582 PMCID: PMC6315102 DOI: 10.1128/mbio.02495-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The symbiotic N2-fixing cyanobacterium UCYN-A, which is closely related to Braarudosphaera bigelowii, and its eukaryotic algal host have been shown to be globally distributed and important in open-ocean N2 fixation. These unique cyanobacteria have reduced metabolic capabilities, even lacking genes for oxygenic photosynthesis and carbon fixation. Cyanobacteria generally use energy from photosynthesis for nitrogen fixation but require mechanisms for avoiding inactivation of the oxygen-sensitive nitrogenase enzyme by ambient oxygen (O2) or the O2 evolved through photosynthesis. This study showed that symbiosis between the N2-fixing cyanobacterium UCYN-A and its eukaryotic algal host has led to adaptation of its daily gene expression pattern in order to enable daytime aerobic N2 fixation, which is likely more energetically efficient than fixing N2 at night, as found in other unicellular marine cyanobacteria. Symbiosis between a marine alga and a N2-fixing cyanobacterium (Cyanobacterium UCYN-A) is geographically widespread in the oceans and is important in the marine N cycle. UCYN-A is uncultivated and is an unusual unicellular cyanobacterium because it lacks many metabolic functions, including oxygenic photosynthesis and carbon fixation, which are typical in cyanobacteria. It is now presumed to be an obligate symbiont of haptophytes closely related to Braarudosphaera bigelowii. N2-fixing cyanobacteria use different strategies to avoid inhibition of N2 fixation by the oxygen evolved in photosynthesis. Most unicellular cyanobacteria temporally separate the two incompatible activities by fixing N2 only at night, but, surprisingly, UCYN-A appears to fix N2 during the day. The goal of this study was to determine how the unicellular UCYN-A strain coordinates N2 fixation and general metabolism compared to other marine cyanobacteria. We found that UCYN-A has distinct daily cycles of many genes despite the fact that it lacks two of the three circadian clock genes found in most cyanobacteria. We also found that the transcription patterns in UCYN-A are more similar to those in marine cyanobacteria that are capable of aerobic N2 fixation in the light, such as Trichodesmium and heterocyst-forming cyanobacteria, than to those in Crocosphaera or Cyanothece species, which are more closely related to unicellular marine cyanobacteria evolutionarily. Our findings suggest that the symbiotic interaction has resulted in a shift of transcriptional regulation to coordinate UCYN-A metabolism with that of the phototrophic eukaryotic host, thus allowing efficient coupling of N2 fixation (by the cyanobacterium) to the energy obtained from photosynthesis (by the eukaryotic unicellular alga) in the light.
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60
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Alcamán-Arias ME, Pedrós-Alió C, Tamames J, Fernández C, Pérez-Pantoja D, Vásquez M, Díez B. Diurnal Changes in Active Carbon and Nitrogen Pathways Along the Temperature Gradient in Porcelana Hot Spring Microbial Mat. Front Microbiol 2018; 9:2353. [PMID: 30333812 PMCID: PMC6176055 DOI: 10.3389/fmicb.2018.02353] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 09/13/2018] [Indexed: 01/14/2023] Open
Abstract
Composition, carbon and nitrogen uptake, and gene transcription of microbial mat communities in Porcelana neutral hot spring (Northern Chilean Patagonia) were analyzed using metagenomics, metatranscriptomics and isotopically labeled carbon (H13CO3) and nitrogen (15NH4Cl and K15NO3) assimilation rates. The microbial mat community included 31 phyla, of which only Cyanobacteria and Chloroflexi were dominant. At 58°C both phyla co-occurred, with similar contributions in relative abundances in metagenomes and total transcriptional activity. At 66°C, filamentous anoxygenic phototrophic Chloroflexi were >90% responsible for the total transcriptional activity recovered, while Cyanobacteria contributed most metagenomics and metatranscriptomics reads at 48°C. According to such reads, phototrophy was carried out both through oxygenic photosynthesis by Cyanobacteria (mostly Mastigocladus) and anoxygenic phototrophy due mainly to Chloroflexi. Inorganic carbon assimilation through the Calvin-Benson cycle was almost exclusively due to Mastigocladus, which was the main primary producer at lower temperatures. Two other CO2 fixation pathways were active at certain times and temperatures as indicated by transcripts: 3-hydroxypropionate (3-HP) bi-cycle due to Chloroflexi and 3-hydroxypropionate-4-hydroxybutyrate (HH) cycle carried out by Thaumarchaeota. The active transcription of the genes involved in these C-fixation pathways correlated with high in situ determined carbon fixation rates. In situ measurements of ammonia assimilation and nitrogen fixation (exclusively attributed to Cyanobacteria and mostly to Mastigocladus sp.) showed these were the most important nitrogen acquisition pathways at 58 and 48°C. At 66°C ammonia oxidation genes were actively transcribed (mostly due to Thaumarchaeota). Reads indicated that denitrification was present as a nitrogen sink at all temperatures and that dissimilatory nitrate reduction to ammonia (DNRA) contributed very little. The combination of metagenomic and metatranscriptomic analysis with in situ assimilation rates, allowed the reconstruction of day and night carbon and nitrogen assimilation pathways together with the contribution of keystone microorganisms in this natural hot spring microbial mat.
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Affiliation(s)
- María E. Alcamán-Arias
- Department of Oceanography, Universidad de Concepción, Concepción, Chile
- Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Center for Climate and Resilience Research, Universidad de Chile, Santiago, Chile
| | - Carlos Pedrós-Alió
- Programa de Biología de Sistemas, Centro Nacional de Biotecnología – Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Javier Tamames
- Programa de Biología de Sistemas, Centro Nacional de Biotecnología – Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Camila Fernández
- Department of Oceanography, Universidad de Concepción, Concepción, Chile
- Laboratoire d’Océanographie Microbienne, Observatoire Océanologique, Sorbonne Universités, Université Pierre-et-Marie-Curie, Centre National de la Recherche Scientifique, Banyuls-sur-Mer, France
- Fondap IDEAL, Universidad Austral de Chile, Valdivia, Chile
| | - Danilo Pérez-Pantoja
- Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Santiago, Chile
| | - Mónica Vásquez
- Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Beatriz Díez
- Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Center for Climate and Resilience Research, Universidad de Chile, Santiago, Chile
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61
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Wei H, Peng C, Yang B, Song H, Li Q, Jiang L, Wei G, Wang K, Wang H, Liu S, Liu X, Chen D, Li Y, Wang M. Contrasting Soil Bacterial Community, Diversity, and Function in Two Forests in China. Front Microbiol 2018; 9:1693. [PMID: 30108560 PMCID: PMC6080587 DOI: 10.3389/fmicb.2018.01693] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 07/06/2018] [Indexed: 12/03/2022] Open
Abstract
Bacteria are the highest abundant microorganisms in the soil. To investigate bacteria community structures, diversity, and functions, contrasting them in four different seasons all the year round with/within two different forest type soils of China. We analyzed soil bacterial community based on 16S rRNA gene sequencing via Illumina HiSeq platform at a temperate deciduous broad-leaved forest (Baotianman, BTM) and a tropical rainforest (Jianfengling, JFL). We obtained 51,137 operational taxonomic units (OTUs) and classified them into 44 phyla and 556 known genera, 18.2% of which had a relative abundance >1%. The composition in each phylum was similar between the two forest sites. Proteobacteria and Acidobacteria were the most abundant phyla in the soil samples between the two forest sites. The Shannon index did not significantly differ among the four seasons at BTM or JFL and was higher at BTM than JFL in each season. The bacteria community at both BTM and JFL showed two significant (P < 0.05) predicted functions related to carbon cycle (anoxygenic photoautotrophy sulfur oxidizing and anoxygenic photoautotrophy) and three significant (P < 0.05) predicted functions related to nitrogen cycle (nitrous denitrificaton, nitrite denitrification, and nitrous oxide denitrification). We provide the basis on how changes in bacterial community composition and diversity leading to differences in carbon and nitrogen cycles at the two forests.
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Affiliation(s)
- Hua Wei
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China.,Medical College, Baoji Vocational Technology College, Baoji, China
| | - Changhui Peng
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China.,Départment des Sciences Biologiques, Institut des Sciences de l'Environnement, Université du Québec à Montréal, Montreal, QC, Canada
| | - Bin Yang
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China
| | - Hanxiong Song
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China
| | - Quan Li
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China
| | - Lin Jiang
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China
| | - Gang Wei
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China
| | - Kefeng Wang
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China
| | - Hui Wang
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China
| | - Shirong Liu
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
| | - Xiaojing Liu
- Baotianman Natural Reserve Administration, Neixiang, China
| | - Dexiang Chen
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
| | - Yide Li
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
| | - Meng Wang
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, China.,State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Institute for Peat and Mire Research, Northeast Normal University, Changchun, China
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62
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Thiel V, Tank M, Bryant DA. Diversity of Chlorophototrophic Bacteria Revealed in the Omics Era. ANNUAL REVIEW OF PLANT BIOLOGY 2018; 69:21-49. [PMID: 29505738 DOI: 10.1146/annurev-arplant-042817-040500] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Because of recent advances in omics methodologies, knowledge of chlorophototrophy (i.e., chlorophyll-based phototrophy) in bacteria has rapidly increased. Chlorophototrophs currently are known to occur in seven bacterial phyla: Cyanobacteria, Proteobacteria, Chlorobi, Chloroflexi, Firmicutes, Acidobacteria, and Gemmatimonadetes. Other organisms that can produce chlorophylls and photochemical reaction centers may still be undiscovered. Here we summarize the current status of the taxonomy and phylogeny of chlorophototrophic bacteria as revealed by genomic methods. In specific cases, we briefly describe important ecophysiological and metabolic insights that have been gained from the application of genomic methods to these bacteria. In the 20 years since the completion of the Synechocystis sp. PCC 6803 genome in 1996, approximately 1,100 genomes have been sequenced, which represents nearly the complete diversity of known chlorophototrophic bacteria. These data are leading to new insights into many important processes, including photosynthesis, nitrogen and carbon fixation, cellular differentiation and development, symbiosis, and ecosystem functionality.
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Affiliation(s)
- Vera Thiel
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan; ,
| | - Marcus Tank
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan; ,
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA;
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA
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63
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Echeverría-Vega A, Chong G, Serrano AE, Guajardo M, Encalada O, Parro V, Blanco Y, Rivas L, Rose KC, Moreno-Paz M, Luque JA, Cabrol NA, Demergasso CS. Watershed-Induced Limnological and Microbial Status in Two Oligotrophic Andean Lakes Exposed to the Same Climatic Scenario. Front Microbiol 2018; 9:357. [PMID: 29556224 PMCID: PMC5844981 DOI: 10.3389/fmicb.2018.00357] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 02/14/2018] [Indexed: 12/04/2022] Open
Abstract
Laguna Negra and Lo Encañado are two oligotrophic Andean lakes forming part of the system fed by meltwater from distinct glacial tongues of the Echaurren glacier in central Chile, which is in a recession period. The recent increase in temperature and decline in precipitation have led to an increase of glacial meltwater and sediments entering these lakes. Although the lacustrine systems are also hydrogeologically connected, the limnology of the lakes is strongly controlled by the surface processes related to the respective sub-watersheds and hydrology. Watershed characteristics (area and length, slope, lithology, resistance to erosion, among others) affect the chemical and physical characteristics of both lakes (e.g., nutrient concentration and turbidity). We studied physical and chemical variables and performed 16S rRNA amplicon sequencing to determine the specific microbial signature of the lakes. The transparency, temperature, turbidity and concentrations of chlorophyll-a, dissolved organic matter, nutrients and the total number of cells, revealed the different status of both lakes at the time of sampling. The predominant bacterial groups in both lakes were Proteobacteria, Verrucomicrobia, and Bacteroidetes. Interestingly, the contribution of phototrophs was significantly higher in LN compared to LE (13 and 4% respectively) and the major fraction corresponded to Anoxygenic Phototrophs (AP) represented by Chloroflexi, Alpha, and Betaproteobacteria. Multivariate analyses showed that the nutrient levels and the light availability of both lakes, which finally depend on the hydrological characteristics of the respective watersheds, explain the differential community composition/function. The abundance of a diverse photoheterotrophic bacterioplankton community suggests that the ability to utilize solar energy along with organic and inorganic substrates is a key function in these oligotrophic mountain lakes.
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Affiliation(s)
| | - Guillermo Chong
- Departamento de Ciencias Geológicas, Universidad Católica de Norte, Antofagasta, Chile
| | - Antonio E Serrano
- Centro de Biotecnología, Universidad Católica del Norte, Antofagasta, Chile
| | - Mariela Guajardo
- Centro de Investigación Científica y Tecnológica para la Minería, Antofagasta, Chile
| | - Olga Encalada
- Centro de Biotecnología, Universidad Católica del Norte, Antofagasta, Chile
| | - Victor Parro
- Department of Molecular Evolution, Centro de Astrobiología (CSIC-INTA), Madrid, Spain
| | - Yolanda Blanco
- Department of Molecular Evolution, Centro de Astrobiología (CSIC-INTA), Madrid, Spain
| | - Luis Rivas
- Department of Molecular Evolution, Centro de Astrobiología (CSIC-INTA), Madrid, Spain
| | - Kevin C Rose
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Mercedes Moreno-Paz
- Department of Molecular Evolution, Centro de Astrobiología (CSIC-INTA), Madrid, Spain
| | - José A Luque
- Departamento de Ciencias Geológicas, Universidad Católica de Norte, Antofagasta, Chile.,Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Antofagasta, Chile
| | - Nathalie A Cabrol
- Carl Sagan Center, SETI Institute, Mountain View, CA, United States.,Space Science Division, NASA Ames Research Center, Moffett Field, CA, United States
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64
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Effect of light wavelength on hot spring microbial mat biodiversity. PLoS One 2018; 13:e0191650. [PMID: 29381713 PMCID: PMC5790269 DOI: 10.1371/journal.pone.0191650] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 01/09/2018] [Indexed: 11/19/2022] Open
Abstract
Hot spring associated phototrophic microbial mats are purely microbial communities, in which phototrophic bacteria function as primary producers and thus shape the community. The microbial mats at Nakabusa hot springs in Japan harbor diverse photosynthetic bacteria, mainly Thermosynechococcus, Chloroflexus, and Roseiflexus, which use light of different wavelength for energy conversion. The aim of this study was to investigate the effect of the phototrophs on biodiversity and community composition in hot spring microbial mats. For this, we specifically activated the different phototrophs by irradiating the mats with different wavelengths in situ. We used 625, 730, and 890 nm wavelength LEDs alone or in combination and confirmed the hypothesized increase in relative abundance of different phototrophs by 16S rRNA gene sequencing. In addition to the increase of the targeted phototrophs, we studied the effect of the different treatments on chemotrophic members. The specific activation of Thermosynechococcus led to increased abundance of several other bacteria, whereas wavelengths specific to Chloroflexus and Roseiflexus induced a decrease in >50% of the community members as compared to the dark conditions. This suggests that the growth of Thermosynechococcus at the surface layer benefits many community members, whereas less benefit is obtained from an increase in filamentous anoxygenic phototrophs Chloroflexus and Roseiflexus. The increases in relative abundance of chemotrophs under different light conditions suggest a relationship between the two groups. Aerobic chemoheterotrophs such as Thermus sp. and Meiothermus sp. are thought to benefit from aerobic conditions and organic carbon in the form of photosynthates by Thermosynechococcus, while the oxidation of sulfide and production of elemental sulfur by filamentous anoxygenic phototrophs benefit the sulfur-disproportionating Caldimicrobium thiodismutans. In this study, we used an experimental approach under controlled environmental conditions for the analysis of natural microbial communities, which proved to be a powerful tool to study interspecies relationships in the microbiome.
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65
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Prieto-Barajas CM, Valencia-Cantero E, Santoyo G. Microbial mat ecosystems: Structure types, functional diversity, and biotechnological application. ELECTRON J BIOTECHN 2018. [DOI: 10.1016/j.ejbt.2017.11.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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66
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Evolution of the 3-hydroxypropionate bicycle and recent transfer of anoxygenic photosynthesis into the Chloroflexi. Proc Natl Acad Sci U S A 2017; 114:10749-10754. [PMID: 28923961 DOI: 10.1073/pnas.1710798114] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Various lines of evidence from both comparative biology and the geologic record make it clear that the biochemical machinery for anoxygenic photosynthesis was present on early Earth and provided the evolutionary stock from which oxygenic photosynthesis evolved ca. 2.3 billion years ago. However, the taxonomic identity of these early anoxygenic phototrophs is uncertain, including whether or not they remain extant. Several phototrophic bacterial clades are thought to have evolved before oxygenic photosynthesis emerged, including the Chloroflexi, a phylum common across a wide range of modern environments. Although Chloroflexi have traditionally been thought to be an ancient phototrophic lineage, genomics has revealed a much greater metabolic diversity than previously appreciated. Here, using a combination of comparative genomics and molecular clock analyses, we show that phototrophic members of the Chloroflexi phylum are not particularly ancient, having evolved well after the rise of oxygen (ca. 867 million years ago), and thus cannot be progenitors of oxygenic photosynthesis. Similarly, results show that the carbon fixation pathway that defines this clade-the 3-hydroxypropionate bicycle-evolved late in Earth history as a result of a series of horizontal gene transfer events, explaining the lack of geological evidence for this pathway based on the carbon isotope record. These results demonstrate the role of horizontal gene transfer in the recent metabolic innovations expressed within this phylum, including its importance in the development of a novel carbon fixation pathway.
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67
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Vuillemin A, Horn F, Alawi M, Henny C, Wagner D, Crowe SA, Kallmeyer J. Preservation and Significance of Extracellular DNA in Ferruginous Sediments from Lake Towuti, Indonesia. Front Microbiol 2017; 8:1440. [PMID: 28798742 PMCID: PMC5529349 DOI: 10.3389/fmicb.2017.01440] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 07/17/2017] [Indexed: 01/20/2023] Open
Abstract
Extracellular DNA is ubiquitous in soil and sediment and constitutes a dominant fraction of environmental DNA in aquatic systems. In theory, extracellular DNA is composed of genomic elements persisting at different degrees of preservation produced by processes occurring on land, in the water column and sediment. Extracellular DNA can be taken up as a nutrient source, excreted or degraded by microorganisms, or adsorbed onto mineral matrices, thus potentially preserving information from past environments. To test whether extracellular DNA records lacustrine conditions, we sequentially extracted extracellular and intracellular DNA from anoxic sediments of ferruginous Lake Towuti, Indonesia. We applied 16S rRNA gene Illumina sequencing on both fractions to discriminate exogenous from endogenous sources of extracellular DNA in the sediment. Environmental sequences exclusively found as extracellular DNA in the sediment originated from multiple sources. For instance, Actinobacteria, Verrucomicrobia, and Acidobacteria derived from soils in the catchment. Limited primary productivity in the water column resulted in few sequences of Cyanobacteria in the oxic photic zone, whereas stratification of the water body mainly led to secondary production by aerobic and anaerobic heterotrophs. Chloroflexi and Planctomycetes, the main degraders of sinking organic matter and planktonic sequences at the water-sediment interface, were preferentially preserved during the initial phase of burial. To trace endogenous sources of extracellular DNA, we used relative abundances of taxa in the intracellular DNA to define which microbial populations grow, decline or persist at low density with sediment depth. Cell lysis became an important additional source of extracellular DNA, gradually covering previous genetic assemblages as other microbial genera became more abundant with depth. The use of extracellular DNA as nutrient by active microorganisms led to selective removal of sequences with lowest GC contents. We conclude that extracellular DNA preserved in shallow lacustrine sediments reflects the initial environmental context, but is gradually modified and thereby shifts from its stratigraphic context. Discrimination of exogenous and endogenous sources of extracellular DNA allows simultaneously addressing in-lake and post-depositional processes. In deeper sediments, the accumulation of resting stages and sequences from cell lysis would require stringent extraction and specific primers if ancient DNA is targeted.
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Affiliation(s)
- Aurèle Vuillemin
- GFZ German Research Centre for Geosciences, Section 5.3: GeomicrobiologyPotsdam, Germany
| | - Fabian Horn
- GFZ German Research Centre for Geosciences, Section 5.3: GeomicrobiologyPotsdam, Germany
| | - Mashal Alawi
- GFZ German Research Centre for Geosciences, Section 5.3: GeomicrobiologyPotsdam, Germany
| | - Cynthia Henny
- Research Center for Limnology, Indonesian Institute of SciencesCibinong-Bogor, Indonesia
| | - Dirk Wagner
- GFZ German Research Centre for Geosciences, Section 5.3: GeomicrobiologyPotsdam, Germany
| | - Sean A. Crowe
- Department of Microbiology and Immunology, University of British Columbia, VancouverBC, Canada
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, VancouverBC, Canada
| | - Jens Kallmeyer
- GFZ German Research Centre for Geosciences, Section 5.3: GeomicrobiologyPotsdam, Germany
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68
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Mobberley JM, Lindemann SR, Bernstein HC, Moran JJ, Renslow RS, Babauta J, Hu D, Beyenal H, Nelson WC. Organismal and spatial partitioning of energy and macronutrient transformations within a hypersaline mat. FEMS Microbiol Ecol 2017; 93:3071443. [PMID: 28334407 PMCID: PMC5812542 DOI: 10.1093/femsec/fix028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/13/2017] [Indexed: 02/06/2023] Open
Abstract
Phototrophic mat communities are model ecosystems for studying energy cycling and elemental transformations because complete biogeochemical cycles occur over millimeter-to-centimeter scales. Characterization of energy and nutrient capture within hypersaline phototrophic mats has focused on specific processes and organisms; however, little is known about community-wide distribution of and linkages between these processes. To investigate energy and macronutrient capture and flow through a structured community, the spatial and organismal distribution of metabolic functions within a compact hypersaline mat community from Hot Lake have been broadly elucidated through species-resolved metagenomics and geochemical, microbial diversity and metabolic gradient measurements. Draft reconstructed genomes of 34 abundant organisms revealed three dominant cyanobacterial populations differentially distributed across the top layers of the mat suggesting niche separation along light and oxygen gradients. Many organisms contained diverse functional profiles, allowing for metabolic response to changing conditions within the mat. Organisms with partial nitrogen and sulfur metabolisms were widespread indicating dependence on metabolite exchange. In addition, changes in community spatial structure were observed over the diel. These results indicate that organisms within the mat community have adapted to the temporally dynamic environmental gradients in this hypersaline mat through metabolic flexibility and fluid syntrophic interactions, including shifts in spatial arrangements.
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Affiliation(s)
- Jennifer M Mobberley
- Biological Science Division, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Stephen R Lindemann
- Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN 47907, USA.,Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Hans C Bernstein
- Biological Science Division, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.,The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - James J Moran
- Chemical and Biological Signature Sciences, National Security Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Ryan S Renslow
- Biological Science Division, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.,The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - Jerome Babauta
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - Dehong Hu
- Environmental Molecular Sciences Laboratory, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Haluk Beyenal
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA
| | - William C Nelson
- Biological Science Division, Earth and Environmental Science Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
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69
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Lindemann SR, Mobberley JM, Cole JK, Markillie LM, Taylor RC, Huang E, Chrisler WB, Wiley HS, Lipton MS, Nelson WC, Fredrickson JK, Romine MF. Predicting Species-Resolved Macronutrient Acquisition during Succession in a Model Phototrophic Biofilm Using an Integrated 'Omics Approach. Front Microbiol 2017; 8:1020. [PMID: 28659875 PMCID: PMC5468372 DOI: 10.3389/fmicb.2017.01020] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/22/2017] [Indexed: 12/27/2022] Open
Abstract
The principles governing acquisition and interspecies exchange of nutrients in microbial communities and how those exchanges impact community productivity are poorly understood. Here, we examine energy and macronutrient acquisition in unicyanobacterial consortia for which species-resolved genome information exists for all members, allowing us to use multi-omic approaches to predict species' abilities to acquire resources and examine expression of resource-acquisition genes during succession. Metabolic reconstruction indicated that a majority of heterotrophic community members lacked the genes required to directly acquire the inorganic nutrients provided in culture medium, suggesting high metabolic interdependency. The sole primary producer in consortium UCC-O, cyanobacterium Phormidium sp. OSCR, displayed declining expression of energy harvest, carbon fixation, and nitrate and sulfate reduction proteins but sharply increasing phosphate transporter expression over 28 days. Most heterotrophic members likewise exhibited signs of phosphorus starvation during succession. Though similar in their responses to phosphorus limitation, heterotrophs displayed species-specific expression of nitrogen acquisition genes. These results suggest niche partitioning around nitrogen sources may structure the community when organisms directly compete for limited phosphate. Such niche complementarity around nitrogen sources may increase community diversity and productivity in phosphate-limited phototrophic communities.
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Affiliation(s)
- Stephen R Lindemann
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States.,Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West LafayetteIN, United States.,Department of Nutrition Science, Purdue University, West LafayetteIN, United States
| | - Jennifer M Mobberley
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States
| | - Jessica K Cole
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States
| | - L M Markillie
- Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West LafayetteIN, United States
| | - Ronald C Taylor
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States
| | - Eric Huang
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States
| | - William B Chrisler
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States
| | - H S Wiley
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, RichlandWA, United States
| | - Mary S Lipton
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, RichlandWA, United States
| | - William C Nelson
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States
| | - James K Fredrickson
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States
| | - Margaret F Romine
- Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, United States
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70
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Thiel V, Hügler M, Ward DM, Bryant DA. The Dark Side of the Mushroom Spring Microbial Mat: Life in the Shadow of Chlorophototrophs. II. Metabolic Functions of Abundant Community Members Predicted from Metagenomic Analyses. Front Microbiol 2017. [PMID: 28634470 PMCID: PMC5459899 DOI: 10.3389/fmicb.2017.00943] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial mat communities in the effluent channels of Octopus and Mushroom Springs within the Lower Geyser Basin of Yellowstone National Park have been extensively characterized. Previous studies have focused on the chlorophototrophic organisms of the phyla Cyanobacteria and Chloroflexi. However, the diversity and metabolic functions of the other portion of the community in the microoxic/anoxic region of the mat are poorly understood. We recently described the diverse but extremely uneven microbial assemblage in the undermat of Mushroom Spring based on 16S rRNA amplicon sequences, which was dominated by Roseiflexus members, filamentous anoxygenic chlorophototrophs. In this study, we analyzed the orange-colored undermat portion of the community of Mushroom Spring mats in a genome-centric approach and discuss the metabolic potentials of the major members. Metagenome binning recovered partial genomes of all abundant community members, ranging in completeness from ~28 to 96%, and allowed affiliation of function with taxonomic identity even for representatives of novel and Candidate phyla. Less complete metagenomic bins correlated with high microdiversity. The undermat portion of the community was found to be a mixture of phototrophic and chemotrophic organisms, which use bicarbonate as well as organic carbon sources derived from different cell components and fermentation products. The presence of rhodopsin genes in many taxa strengthens the hypothesis that light energy is of major importance. Evidence for the usage of all four bacterial carbon fixation pathways was found in the metagenome. Nitrogen fixation appears to be limited to Synechococcus spp. in the upper mat layer and Thermodesulfovibrio sp. in the undermat, and nitrate/nitrite metabolism was limited. A closed sulfur cycle is indicated by biological sulfate reduction combined with the presence of genes for sulfide oxidation mainly in phototrophs. Finally, a variety of undermat microorganisms have genes for hydrogen production and consumption, which leads to the observed diel hydrogen concentration patterns.
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Affiliation(s)
- Vera Thiel
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University ParkPA, United States
| | - Michael Hügler
- Department Microbiology and Molecular Biology, DVGW-Technologiezentrum WasserKarlsruhe, Germany
| | - David M Ward
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, United States
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University ParkPA, United States.,Department of Chemistry and Biochemistry, Montana State UniversityBozeman, MT, United States
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71
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Budinich M, Bourdon J, Larhlimi A, Eveillard D. A multi-objective constraint-based approach for modeling genome-scale microbial ecosystems. PLoS One 2017; 12:e0171744. [PMID: 28187207 PMCID: PMC5302800 DOI: 10.1371/journal.pone.0171744] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/25/2017] [Indexed: 12/20/2022] Open
Abstract
Interplay within microbial communities impacts ecosystems on several scales, and elucidation of the consequent effects is a difficult task in ecology. In particular, the integration of genome-scale data within quantitative models of microbial ecosystems remains elusive. This study advocates the use of constraint-based modeling to build predictive models from recent high-resolution -omics datasets. Following recent studies that have demonstrated the accuracy of constraint-based models (CBMs) for simulating single-strain metabolic networks, we sought to study microbial ecosystems as a combination of single-strain metabolic networks that exchange nutrients. This study presents two multi-objective extensions of CBMs for modeling communities: multi-objective flux balance analysis (MO-FBA) and multi-objective flux variability analysis (MO-FVA). Both methods were applied to a hot spring mat model ecosystem. As a result, multiple trade-offs between nutrients and growth rates, as well as thermodynamically favorable relative abundances at community level, were emphasized. We expect this approach to be used for integrating genomic information in microbial ecosystems. Following models will provide insights about behaviors (including diversity) that take place at the ecosystem scale.
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Affiliation(s)
- Marko Budinich
- Computational Biology group, LINA UMR 6241 CNRS, EMN, Université de Nantes, Nantes, France
| | - Jérémie Bourdon
- Computational Biology group, LINA UMR 6241 CNRS, EMN, Université de Nantes, Nantes, France
| | - Abdelhalim Larhlimi
- Computational Biology group, LINA UMR 6241 CNRS, EMN, Université de Nantes, Nantes, France
| | - Damien Eveillard
- Computational Biology group, LINA UMR 6241 CNRS, EMN, Université de Nantes, Nantes, France
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72
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In Situ Hydrogen Dynamics in a Hot Spring Microbial Mat during a Diel Cycle. Appl Environ Microbiol 2016; 82:4209-4217. [PMID: 27208140 DOI: 10.1128/aem.00710-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 04/29/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Microbes can produce molecular hydrogen (H2) via fermentation, dinitrogen fixation, or direct photolysis, yet the H2 dynamics in cyanobacterial communities has only been explored in a few natural systems and mostly in the laboratory. In this study, we investigated the diel in situ H2 dynamics in a hot spring microbial mat, where various ecotypes of unicellular cyanobacteria (Synechococcus sp.) are the only oxygenic phototrophs. In the evening, H2 accumulated rapidly after the onset of darkness, reaching peak values of up to 30 μmol H2 liter(-1) at about 1-mm depth below the mat surface, slowly decreasing to about 11 μmol H2 liter(-1) just before sunrise. Another pulse of H2 production, reaching a peak concentration of 46 μmol H2 liter(-1), was found in the early morning under dim light conditions too low to induce accumulation of O2 in the mat. The light stimulation of H2 accumulation indicated that nitrogenase activity was an important source of H2 during the morning. This is in accordance with earlier findings of a distinct early morning peak in N2 fixation and expression of Synechococcus nitrogenase genes in mat samples from the same location. Fermentation might have contributed to the formation of H2 during the night, where accumulation of other fermentation products lowered the pH in the mat to less than pH 6 compared to a spring source pH of 8.3. IMPORTANCE Hydrogen is a key intermediate in anaerobic metabolism, and with the development of a sulfide-insensitive microsensor for H2, it is now possible to study the microdistribution of H2 in stratified microbial communities such as the photosynthetic microbial mat investigated here. The ability to measure H2 profiles within the mat compared to previous measurements of H2 emission gives much more detailed information about the sources and sinks of H2 in such communities, and it was demonstrated that the high rates of H2 formation in the early morning when the mat was exposed to low light intensities might be explained by nitrogen fixation, where H2 is formed as a by-product.
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73
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Thiel V, Wood JM, Olsen MT, Tank M, Klatt CG, Ward DM, Bryant DA. The Dark Side of the Mushroom Spring Microbial Mat: Life in the Shadow of Chlorophototrophs. I. Microbial Diversity Based on 16S rRNA Gene Amplicons and Metagenomic Sequencing. Front Microbiol 2016; 7:919. [PMID: 27379049 PMCID: PMC4911352 DOI: 10.3389/fmicb.2016.00919] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 05/27/2016] [Indexed: 11/13/2022] Open
Abstract
Microbial-mat communities in the effluent channels of Octopus and Mushroom Springs within the Lower Geyser Basin at Yellowstone National Park have been studied for nearly 50 years. The emphasis has mostly focused on the chlorophototrophic bacterial organisms of the phyla Cyanobacteria and Chloroflexi. In contrast, the diversity and metabolic functions of the heterotrophic community in the microoxic/anoxic region of the mat are not well understood. In this study we analyzed the orange-colored undermat of the microbial community of Mushroom Spring using metagenomic and rRNA-amplicon (iTag) analyses. Our analyses disclosed a highly diverse community exhibiting a high degree of unevenness, strongly dominated by a single taxon, the filamentous anoxygenic phototroph, Roseiflexus spp. The second most abundant organisms belonged to the Thermotogae, which have been hypothesized to be a major source of H2 from fermentation that could enable photomixotrophic metabolism by Chloroflexus and Roseiflexus spp. Other abundant organisms include two members of the Armatimonadetes (OP10); Thermocrinis sp.; and phototrophic and heterotrophic members of the Chloroflexi. Further, an Atribacteria (OP9/JS1) member; a sulfate-reducing Thermodesulfovibrio sp.; a Planctomycetes member; a member of the EM3 group tentatively affiliated with the Thermotogae, as well as a putative member of the Arminicenantes (OP8) represented ≥1% of the reads. Archaea were not abundant in the iTag analysis, and no metagenomic bin representing an archaeon was identified. A high microdiversity of 16S rRNA gene sequences was identified for the dominant taxon, Roseiflexus spp. Previous studies demonstrated that highly similar Synechococcus variants in the upper layer of the mats represent ecological species populations with specific ecological adaptations. This study suggests that similar putative ecotypes specifically adapted to different niches occur within the undermat community, particularly for Roseiflexus spp.
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Affiliation(s)
- Vera Thiel
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University University Park, PA, USA
| | - Jason M Wood
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Millie T Olsen
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Marcus Tank
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University University Park, PA, USA
| | - Christian G Klatt
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA; Agricultural Research Service, United States Department of Agriculture, University of MinnesotaSaint Paul, MN, USA
| | - David M Ward
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State UniversityUniversity Park, PA, USA; Department of Chemistry and Biochemistry, Montana State UniversityBozeman, MT, USA
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Abstract
Bacteria have traditionally been studied as single-cell organisms. In laboratory settings, aerobic bacteria are usually cultured in aerated flasks, where the cells are considered essentially homogenous. However, in many natural environments, bacteria and other microorganisms grow in mixed communities, often associated with surfaces. Biofilms are comprised of surface-associated microorganisms, their extracellular matrix material, and environmental chemicals that have adsorbed to the bacteria or their matrix material. While this definition of a biofilm is fairly simple, biofilms are complex and dynamic. Our understanding of the activities of individual biofilm cells and whole biofilm systems has developed rapidly, due in part to advances in molecular, analytical, and imaging tools and the miniaturization of tools designed to characterize biofilms at the enzyme level, cellular level, and systems level.
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Zepeda Mendoza ML, Lundberg J, Ivarsson M, Campos P, Nylander JAA, Sallstedt T, Dalen L. Metagenomic Analysis from the Interior of a Speleothem in Tjuv-Ante's Cave, Northern Sweden. PLoS One 2016; 11:e0151577. [PMID: 26985997 PMCID: PMC4795671 DOI: 10.1371/journal.pone.0151577] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 03/01/2016] [Indexed: 02/01/2023] Open
Abstract
Speleothems are secondary mineral deposits normally formed by water supersaturated with calcium carbonate percolating into underground caves, and are often associated with low-nutrient and mostly non-phototrophic conditions. Tjuv-Ante's cave is a shallow-depth cave formed by the action of waves, with granite and dolerite as major components, and opal-A and calcite as part of the speleothems, making it a rare kind of cave. We generated two DNA shotgun sequencing metagenomic datasets from the interior of a speleothem from Tjuv-Ante's cave representing areas of old and relatively recent speleothem formation. We used these datasets to perform i) an evaluation of the use of these speleothems as past biodiversity archives, ii) functional and taxonomic profiling of the speleothem's different formation periods, and iii) taxonomic comparison of the metagenomic results to previous microscopic analyses from a nearby speleothem of the same cave. Our analyses confirm the abundance of Actinobacteria and fungi as previously reported by microscopic analyses on this cave, however we also discovered a larger biodiversity. Interestingly, we identified photosynthetic genes, as well as genes related to iron and sulphur metabolism, suggesting the presence of chemoautotrophs. Furthermore, we identified taxa and functions related to biomineralization. However, we could not confidently establish the use of this type of speleothems as biological paleoarchives due to the potential leaching from the outside of the cave and the DNA damage that we propose has been caused by the fungal chemical etching.
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Affiliation(s)
| | - Johannes Lundberg
- Department of Botany, Swedish Museum of Natural History, Stockholm, Sweden
| | - Magnus Ivarsson
- Department of Palaeobiology and the Nordic Center for Earth Evolution (NordCEE), Swedish Museum of Natural History, Stockholm, Sweden
| | - Paula Campos
- Centre for GeoGenetics, University of Copenhagen, Natural History Museum of Denmark, Copenhagen, Denmark
| | - Johan A. A. Nylander
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
| | - Therese Sallstedt
- Department of Palaeobiology and the Nordic Center for Earth Evolution (NordCEE), Swedish Museum of Natural History, Stockholm, Sweden
| | - Love Dalen
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
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76
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Gaisin VA, Grouzdev DS, Namsaraev ZB, Sukhacheva MV, Gorlenko VM, Kuznetsov BB. Biogeography of thermophilic phototrophic bacteria belonging toRoseiflexusgenus. FEMS Microbiol Ecol 2016; 92:fiw012. [DOI: 10.1093/femsec/fiw012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2016] [Indexed: 11/14/2022] Open
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77
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Nozhevnikova AN, Botchkova EA, Plakunov VK. Multi-species biofilms in ecology, medicine, and biotechnology. Microbiology (Reading) 2015. [DOI: 10.1134/s0026261715060107] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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78
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Badhai J, Ghosh TS, Das SK. Taxonomic and functional characteristics of microbial communities and their correlation with physicochemical properties of four geothermal springs in Odisha, India. Front Microbiol 2015; 6:1166. [PMID: 26579081 PMCID: PMC4620158 DOI: 10.3389/fmicb.2015.01166] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/08/2015] [Indexed: 12/31/2022] Open
Abstract
This study describes microbial diversity in four tropical hot springs representing moderately thermophilic environments (temperature range: 40–58°C; pH: 7.2–7.4) with discrete geochemistry. Metagenome sequence data showed a dominance of Bacteria over Archaea; the most abundant phyla were Chloroflexi and Proteobacteria, although other phyla were also present, such as Acetothermia, Nitrospirae, Acidobacteria, Firmicutes, Deinococcus-Thermus, Bacteroidetes, Thermotogae, Euryarchaeota, Verrucomicrobia, Ignavibacteriae, Cyanobacteria, Actinobacteria, Planctomycetes, Spirochaetes, Armatimonadetes, Crenarchaeota, and Aquificae. The distribution of major genera and their statistical correlation analyses with the physicochemical parameters predicted that the temperature, aqueous concentrations of ions (such as sodium, chloride, sulfate, and bicarbonate), total hardness, dissolved solids and conductivity were the main environmental variables influencing microbial community composition and diversity. Despite the observed high taxonomic diversity, there were only little variations in the overall functional profiles of the microbial communities in the four springs. Genes involved in the metabolism of carbohydrates and carbon fixation were the most abundant functional class of genes present in these hot springs. The distribution of genes involved in carbon fixation predicted the presence of all the six known autotrophic pathways in the metagenomes. A high prevalence of genes involved in membrane transport, signal transduction, stress response, bacterial chemotaxis, and flagellar assembly were observed along with genes involved in the pathways of xenobiotic degradation and metabolism. The analysis of the metagenomic sequences affiliated to the candidate phylum Acetothermia from spring TB-3 provided new insight into the metabolism and physiology of yet-unknown members of this lineage of bacteria.
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Affiliation(s)
- Jhasketan Badhai
- Department of Biotechnology, Institute of Life Sciences Bhubaneswar, India
| | | | - Subrata K Das
- Department of Biotechnology, Institute of Life Sciences Bhubaneswar, India
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79
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Estrella Alcamán M, Fernandez C, Delgado A, Bergman B, Díez B. The cyanobacterium Mastigocladus fulfills the nitrogen demand of a terrestrial hot spring microbial mat. THE ISME JOURNAL 2015; 9:2290-303. [PMID: 26230049 PMCID: PMC4579480 DOI: 10.1038/ismej.2015.63] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 11/09/2022]
Abstract
Cyanobacteria from Subsection V (Stigonematales) are important components of microbial mats in non-acidic terrestrial hot springs. Despite their diazotrophic nature (N2 fixers), their impact on the nitrogen cycle in such extreme ecosystems remains unknown. Here, we surveyed the identity and activity of diazotrophic cyanobacteria in the neutral hot spring of Porcelana (Northern Patagonia, Chile) during 2009 and 2011-2013. We used 16S rRNA and the nifH gene to analyze the distribution and diversity of diazotrophic cyanobacteria. Our results demonstrate the dominance of the heterocystous genus Mastigocladus (Stigonematales) along the entire temperature gradient of the hot spring (69-38 °C). In situ nitrogenase activity (acetylene reduction), nitrogen fixation rates (cellular uptake of (15)N2) and nifH transcription levels in the microbial mats showed that nitrogen fixation and nifH mRNA expression were light-dependent. Nitrogen fixation activities were detected at temperatures ranging from 58 °C to 46 °C, with maximum daily rates of 600 nmol C2H4 cm(-2) per day and 94.1 nmol N cm(-2) per day. These activity patterns strongly suggest a heterocystous cyanobacterial origin and reveal a correlation between nitrogenase activity and nifH gene expression during diurnal cycles in thermal microbial mats. N and C fixation in the mats contributed ~3 g N m(-2) per year and 27 g C m(-2) per year, suggesting that these vital demands are fully met by the diazotrophic and photoautotrophic capacities of the cyanobacteria in the Porcelana hot spring.
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Affiliation(s)
- María Estrella Alcamán
- Department of Molecular Genetics and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Camila Fernandez
- Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, Sorbonne Universités, UPMC Univ Paris 06, UMR 7621, Banyuls/mer, France
- CNRS, UMR 7621, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, Banyuls/mer, France
- Department of Oceanography, Interdisciplinary Center for Aquaculture Research (INCAR) and COPAS SURAUSTRAL Program, University of Concepción, Concepción, Chile
| | - Antonio Delgado
- Instituto Andaluz de Ciencias de la Tierra (CSIC-Univ. Granada), Armilla, Granada, Spain
| | - Birgitta Bergman
- Department of Ecology, Environment and Plant Sciences and Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Beatriz Díez
- Department of Molecular Genetics and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Center for Climate and Resilience Research (CR)2, Santiago, Chile
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80
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Kim YM, Nowack S, Olsen MT, Becraft ED, Wood JM, Thiel V, Klapper I, Kühl M, Fredrickson JK, Bryant DA, Ward DM, Metz TO. Diel metabolomics analysis of a hot spring chlorophototrophic microbial mat leads to new hypotheses of community member metabolisms. Front Microbiol 2015; 6:209. [PMID: 25941514 PMCID: PMC4400912 DOI: 10.3389/fmicb.2015.00209] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/02/2015] [Indexed: 11/29/2022] Open
Abstract
Dynamic environmental factors such as light, nutrients, salt, and temperature continuously affect chlorophototrophic microbial mats, requiring adaptive and acclimative responses to stabilize composition and function. Quantitative metabolomics analysis can provide insights into metabolite dynamics for understanding community response to such changing environmental conditions. In this study, we quantified volatile organic acids, polar metabolites (amino acids, glycolytic and citric acid cycle intermediates, nucleobases, nucleosides, and sugars), wax esters, and polyhydroxyalkanoates, resulting in the identification of 104 metabolites and related molecules in thermal chlorophototrophic microbial mat cores collected over a diel cycle in Mushroom Spring, Yellowstone National Park. A limited number of predominant taxa inhabit this community and their functional potentials have been previously identified through metagenomic and metatranscriptomic analyses and in situ metabolisms, and metabolic interactions among these taxa have been hypothesized. Our metabolomics results confirmed the diel cycling of photorespiration (e.g., glycolate) and fermentation (e.g., acetate, propionate, and lactate) products, the carbon storage polymers polyhydroxyalkanoates, and dissolved gasses (e.g., H2 and CO2) in the waters overlying the mat, which were hypothesized to occur in major mat chlorophototrophic community members. In addition, we have formulated the following new hypotheses: (1) the morning hours are a time of biosynthesis of amino acids, DNA, and RNA; (2) photo-inhibited cells may also produce lactate via fermentation as an alternate metabolism; (3) glycolate and lactate are exchanged among Synechococcus and Roseiflexus spp.; and (4) fluctuations in many metabolite pools (e.g., wax esters) at different times of day result from species found at different depths within the mat responding to temporal differences in their niches.
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Affiliation(s)
- Young-Mo Kim
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
| | - Shane Nowack
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
- Department of Mathematical Sciences, Montana State UniversityBozeman, MT, USA
| | - Millie T. Olsen
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | - Eric D. Becraft
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | - Jason M. Wood
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | - Vera Thiel
- Department of Biochemistry and Molecular Biology, The Pennsylvania State UniversityUniversity Park, PA, USA
| | - Isaac Klapper
- Department of Mathematical Sciences, Montana State UniversityBozeman, MT, USA
- Department of Mathematics, Temple UniversityPhiladelphia, PA, USA
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of CopenhagenHelsingør, Denmark
- Plant Functional Biology and Climate Change Cluster, University of Technology SydneyUltimo, NSW, Australia
| | - James K. Fredrickson
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State UniversityUniversity Park, PA, USA
- Department of Chemistry and Biochemistry, Montana State UniversityBozeman, MT, USA
| | - David M. Ward
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | - Thomas O. Metz
- Biological Sciences Division, Pacific Northwest National LaboratoryRichland, WA, USA
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81
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López NI, Pettinari MJ, Nikel PI, Méndez BS. Polyhydroxyalkanoates: Much More than Biodegradable Plastics. ADVANCES IN APPLIED MICROBIOLOGY 2015; 93:73-106. [PMID: 26505689 DOI: 10.1016/bs.aambs.2015.06.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Bacterial polyhydroxyalkanoates (PHAs) are isotactic polymers that play a critical role in central metabolism, as they act as dynamic reservoirs of carbon and reducing equivalents. These polymers have a number of technical applications since they exhibit thermoplastic and elastomeric properties, making them attractive as a replacement of oil-derived materials. PHAs are accumulated under conditions of nutritional imbalance (usually an excess of carbon source with respect to a limiting nutrient, such as nitrogen or phosphorus). The cycle of PHA synthesis and degradation has been recognized as an important physiological feature when these biochemical pathways were originally described, yet its role in bacterial processes as diverse as global regulation and cell survival is just starting to be appreciated in full. In the present revision, the complex regulation of PHA synthesis and degradation at the transcriptional, translational, and metabolic levels are explored by analyzing examples in natural producer bacteria, such as Pseudomonas species, as well as in recombinant Escherichia coli strains. The ecological role of PHAs, together with the interrelations with other polymers and extracellular substances, is also discussed, along with their importance in cell survival, resistance to several types of environmental stress, and planktonic-versus-biofilm lifestyle. Finally, bioremediation and plant growth promotion are presented as examples of environmental applications in which PHA accumulation has successfully been exploited.
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82
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Thermophilic microbial cellulose decomposition and methanogenesis pathways recharacterized by metatranscriptomic and metagenomic analysis. Sci Rep 2014; 4:6708. [PMID: 25330991 PMCID: PMC4204047 DOI: 10.1038/srep06708] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 10/02/2014] [Indexed: 02/01/2023] Open
Abstract
The metatranscriptomic recharacterization in the present study captured microbial enzymes at the unprecedented scale of 40,000 active genes belonged to 2,269 KEGG functions were identified. The novel information obtained herein revealed interesting patterns and provides an initial transcriptional insight into the thermophilic cellulose methanization process. Synergistic beta-sugar consumption by Thermotogales is crucial for cellulose hydrolysis in the thermophilic cellulose-degrading consortium because the primary cellulose degraders Clostridiales showed metabolic incompetence in subsequent beta-sugar pathways. Additionally, comparable transcription of putative Sus-like polysaccharide utilization loci (PULs) was observed in an unclassified order of Bacteroidetes suggesting the importance of PULs mechanism for polysaccharides breakdown in thermophilic systems. Despite the abundance of acetate as a fermentation product, the acetate-utilizing Methanosarcinales were less prevalent by 60% than the hydrogenotrophic Methanobacteriales. Whereas the aceticlastic methanogenesis pathway was markedly more active in terms of transcriptional activities in key genes, indicating that the less dominant Methanosarcinales are more active than their hydrogenotrophic counterparts in methane metabolism. These findings suggest that the minority of aceticlastic methanogens are not necessarily associated with repressed metabolism, in a pattern that was commonly observed in the cellulose-based methanization consortium, and thus challenge the causal likelihood proposed by previous studies.
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83
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Increasing phytoremediation efficiency and reliability using novel omics approaches. Trends Biotechnol 2014; 32:271-80. [DOI: 10.1016/j.tibtech.2014.02.008] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 02/12/2014] [Accepted: 02/26/2014] [Indexed: 01/19/2023]
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84
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Lee JZ, Burow LC, Woebken D, Everroad RC, Kubo MD, Spormann AM, Weber PK, Pett-Ridge J, Bebout BM, Hoehler TM. Fermentation couples Chloroflexi and sulfate-reducing bacteria to Cyanobacteria in hypersaline microbial mats. Front Microbiol 2014; 5:61. [PMID: 24616716 PMCID: PMC3935151 DOI: 10.3389/fmicb.2014.00061] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 01/30/2014] [Indexed: 11/17/2022] Open
Abstract
Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB). However, the mechanisms and magnitude of hydrogen cycling have not been extensively studied. Two mats types near Guerrero Negro, Mexico-permanently submerged Microcoleus microbial mat (GN-S), and intertidal Lyngbya microbial mat (GN-I)-were used in microcosm diel manipulation experiments with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), molybdate, ammonium addition, and physical disruption to understand the processes responsible for hydrogen cycling between mat microbes. Across microcosms, H2 production occurred under dark anoxic conditions with simultaneous production of a suite of organic acids. H2 production was not significantly affected by inhibition of nitrogen fixation, but rather appears to result from constitutive fermentation of photosynthetic storage products by oxygenic phototrophs. Comparison to accumulated glycogen and to CO2 flux indicated that, in the GN-I mat, fermentation released almost all of the carbon fixed via photosynthesis during the preceding day, primarily as organic acids. Across mats, although oxygenic and anoxygenic phototrophs were detected, cyanobacterial [NiFe]-hydrogenase transcripts predominated. Molybdate inhibition experiments indicated that SRBs from a wide distribution of DsrA phylotypes were responsible for H2 consumption. Incubation with (13)C-acetate and NanoSIMS (secondary ion mass-spectrometry) indicated higher uptake in both Chloroflexi and SRBs relative to other filamentous bacteria. These manipulations and diel incubations confirm that Cyanobacteria were the main fermenters in Guerrero Negro mats and that the net flux of nighttime fermentation byproducts (not only hydrogen) was largely regulated by the interplay between Cyanobacteria, SRBs, and Chloroflexi.
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Affiliation(s)
- Jackson Z. Lee
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
- Bay Area Environmental Research InstituteSonoma, CA, USA
| | - Luke C. Burow
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
- Departments of Civil and Environmental Engineering, and Chemical Engineering, Stanford UniversityStanford, CA, USA
| | - Dagmar Woebken
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
- Departments of Civil and Environmental Engineering, and Chemical Engineering, Stanford UniversityStanford, CA, USA
| | | | - Mike D. Kubo
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
- The SETI InstituteMountain View, CA, USA
| | - Alfred M. Spormann
- Departments of Civil and Environmental Engineering, and Chemical Engineering, Stanford UniversityStanford, CA, USA
| | - Peter K. Weber
- Lawrence Livermore National Lab, Chemical Sciences DivisionLivermore, CA, USA
| | - Jennifer Pett-Ridge
- Lawrence Livermore National Lab, Chemical Sciences DivisionLivermore, CA, USA
| | - Brad M. Bebout
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
| | - Tori M. Hoehler
- Exobiology Branch, NASA Ames Research CenterMoffett Field, CA, USA
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85
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Slysz GW, Steinke L, Ward DM, Klatt CG, Clauss TRW, Purvine SO, Payne SH, Anderson GA, Smith RD, Lipton MS. Automated data extraction from in situ protein-stable isotope probing studies. J Proteome Res 2014; 13:1200-10. [PMID: 24467184 DOI: 10.1021/pr400633j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Protein-stable isotope probing (protein-SIP) has strong potential for revealing key metabolizing taxa in complex microbial communities. While most protein-SIP work to date has been performed under controlled laboratory conditions to allow extensive isotope labeling of the target organism(s), a key application will be in situ studies of microbial communities for short periods of time under natural conditions that result in small degrees of partial labeling. One hurdle restricting large-scale in situ protein-SIP studies is the lack of algorithms and software for automated data processing of the massive data sets resulting from such studies. In response, we developed Stable Isotope Probing Protein Extraction Resources software (SIPPER) and applied it for large-scale extraction and visualization of data from short-term (3 h) protein-SIP experiments performed in situ on phototrophic bacterial mats isolated from Yellowstone National Park. Several metrics incorporated into the software allow it to support exhaustive analysis of the complex composite isotopic envelope observed as a result of low amounts of partial label incorporation. SIPPER also enables the detection of labeled molecular species without the need for any prior identification.
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Affiliation(s)
- Gordon W Slysz
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
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86
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Klatt CG, Inskeep WP, Herrgard MJ, Jay ZJ, Rusch DB, Tringe SG, Niki Parenteau M, Ward DM, Boomer SM, Bryant DA, Miller SR. Community structure and function of high-temperature chlorophototrophic microbial mats inhabiting diverse geothermal environments. Front Microbiol 2013; 4:106. [PMID: 23761787 PMCID: PMC3669762 DOI: 10.3389/fmicb.2013.00106] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Accepted: 04/13/2013] [Indexed: 11/13/2022] Open
Abstract
Six phototrophic microbial mat communities from different geothermal springs (YNP) were studied using metagenome sequencing and geochemical analyses. The primary goals of this work were to determine differences in community composition of high-temperature phototrophic mats distributed across the Yellowstone geothermal ecosystem, and to identify metabolic attributes of predominant organisms present in these communities that may correlate with environmental attributes important in niche differentiation. Random shotgun metagenome sequences from six phototrophic communities (average ∼53 Mbp/site) were subjected to multiple taxonomic, phylogenetic, and functional analyses. All methods, including G + C content distribution, MEGAN analyses, and oligonucleotide frequency-based clustering, provided strong support for the dominant community members present in each site. Cyanobacteria were only observed in non-sulfidic sites; de novo assemblies were obtained for Synechococcus-like populations at Chocolate Pots (CP_7) and Fischerella-like populations at White Creek (WC_6). Chloroflexi-like sequences (esp. Roseiflexus and/or Chloroflexus spp.) were observed in all six samples and contained genes involved in bacteriochlorophyll biosynthesis and the 3-hydroxypropionate carbon fixation pathway. Other major sequence assemblies were obtained for a Chlorobiales population from CP_7 (proposed family Thermochlorobacteriaceae), and an anoxygenic, sulfur-oxidizing Thermochromatium-like (Gamma-proteobacteria) population from Bath Lake Vista Annex (BLVA_20). Additional sequence coverage is necessary to establish more complete assemblies of other novel bacteria in these sites (e.g., Bacteroidetes and Firmicutes); however, current assemblies suggested that several of these organisms play important roles in heterotrophic and fermentative metabolisms. Definitive linkages were established between several of the dominant phylotypes present in these habitats and important functional processes such as photosynthesis, carbon fixation, sulfur oxidation, and fermentation.
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Affiliation(s)
- Christian G Klatt
- Department of Land Resources and Environmental Sciences, Montana State University , Bozeman, MT , USA ; Thermal Biology Institute, Montana State University , Bozeman, MT , USA
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