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Saini JS, Manni M, Hassler C, Cable RN, Duhaime MB, Zdobnov EM. Genomic insights into the coupling of a Chlorella-like microeukaryote and sulfur bacteria in the chemocline of permanently stratified Lake Cadagno. THE ISME JOURNAL 2023; 17:903-915. [PMID: 37031343 DOI: 10.1038/s41396-023-01396-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 04/10/2023]
Abstract
Meromictic Lake Cadagno is a permanently stratified system with a persistent microbial bloom within the oxic-anoxic boundary called the chemocline. The association between oxygenic and anoxygenic photosynthesis within the chemocline has been known for at least two decades. Although anoxygenic purple and green sulfur bacteria have been well studied, reports on oxygenic phytoplankton have remained sparse since their discovery in the 1920s. Nearly a century later, this study presents the first near-complete genome of a photosynthetic microbial eukaryote from the chemocline of Lake Cadagno, provisionally named Chlorella-like MAG. The 18.9 Mbp nuclear genome displays a high GC content (71.5%), and the phylogenetic placement suggests that it is a novel species of the genus Chlorella of Chlorophytes. Functional annotation of the Chlorella-like metagenome-assembled genome predicted 10,732 protein-coding genes, with an approximate 0.6% proportion potentially involved in carbon, sulfur, and nitrogen (C, N, and S) metabolism. In addition to C4 photosynthesis, this study detected genes for heat shock proteins (HSPs) in the Chlorella-like algae, consistent with the other Chlorella species. Altogether, the genomic insights in this study suggest the cooperation of photosynthetic algae with phototrophic sulfur bacteria via C, N, and S metabolism, which may aid their collective persistence in the Lake Cadagno chemocline. Furthermore, this work additionally presents the chloroplast genome of Cryptomonas-like species, which was likely to be presumed as cyanobacteria in previous studies because of the presence of phycobilisomes.
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Affiliation(s)
- Jaspreet S Saini
- Department F.-A Forel for Environmental and Aquatic Sciences, Earth and Environmental Sciences, University of Geneva, Geneva, Switzerland.
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Mosè Manni
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Christel Hassler
- Department F.-A Forel for Environmental and Aquatic Sciences, Earth and Environmental Sciences, University of Geneva, Geneva, Switzerland
- Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland
| | - Rachel N Cable
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Melissa B Duhaime
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Evgeny M Zdobnov
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
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2
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Grouzdev D, Gaisin V, Lunina O, Krutkina M, Krasnova E, Voronov D, Baslerov R, Sigalevich P, Savvichev A, Gorlenko V. Microbial communities of stratified aquatic ecosystems of Kandalaksha Bay (White Sea) shed light on the evolutionary history of green and brown morphotypes of Chlorobiota. FEMS Microbiol Ecol 2022; 98:6693937. [PMID: 36073352 DOI: 10.1093/femsec/fiac103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 12/14/2022] Open
Abstract
Anoxygenic photoautotrophic metabolism of green sulfur bacteria of the family Chlorobiaceae played a significant role in establishing the Earth's biosphere. Two known major ecological forms of these phototrophs differ in their pigment composition and, therefore, in color: the green and brown forms. The latter form often occurs in low-light environments and is specialized to harvest blue light, which can penetrate to the greatest depth in the water column. In the present work, metagenomic sequencing was used to investigate the natural population of brown Chl. phaeovibrioides ZM in a marine stratified Zeleny Mys lagoon in the Kandalaksha Bay (the White Sea) to supplement the previously obtained genomes of brown Chlorobiaceae. The genomes of brown and green Chlorobiaceae were investigated using comparative genome analysis and phylogenetic and reconciliation analysis to reconstruct the evolution of these ecological forms. Our results support the suggestion that the last common ancestor of Chlorobiaceae belonged to the brown form, i.e. it was adapted to the conditions of low illumination. However, despite the vertical inheritance of these characteristics, among modern Chlorobiaceae populations, the genes responsible for synthesizing the pigments of the brown form are subject to active horizontal transfer.
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Affiliation(s)
- Denis Grouzdev
- SciBear OU, 10115 Tallinn, Estonia.,School of Marine and Atmospheric Sciences, Stony Brook University, 11794, Stony Brook, USA
| | - Vasil Gaisin
- Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia.,Current affiliation: Institute of Molecular Biology & Biophysics, Eidgenössische Technische Hochschule Zürich, Zurich, Switzerland
| | - Olga Lunina
- Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia
| | | | - Elena Krasnova
- Pertsov White Sea Biological Station, 184042, Republic Karelia, Russia
| | - Dmitry Voronov
- Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, 127051, Moscow, Russia
| | - Roman Baslerov
- Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia
| | - Pavel Sigalevich
- Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia
| | - Alexander Savvichev
- Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia
| | - Vladimir Gorlenko
- Research Center of Biotechnology of the Russian Academy of Sciences, 119071, Moscow, Russia
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3
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Kuzyk SB, Ma X, Yurkov V. Seasonal Dynamics of Lake Winnipeg’s Microbial Communities Reveal Aerobic Anoxygenic Phototrophic Populations Coincide with Sunlight Availability. Microorganisms 2022; 10:microorganisms10091690. [PMID: 36144291 PMCID: PMC9501198 DOI: 10.3390/microorganisms10091690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/12/2022] [Accepted: 08/19/2022] [Indexed: 11/30/2022] Open
Abstract
In this first comprehensive study of Lake Winnipeg’s microbial communities, limnetic and littoral euphotic zones were examined during each season from 2016 through 2020. Classical cultivation and modern high-throughput sequencing techniques provided quantification and identification of key phototrophic populations, including aerobic anoxygenic phototrophs (AAP). Annual dynamics found total heterotrophs reached 4.23 × 106 CFU/g in littoral sands, and 7.69 × 104 CFU/mL in summer littoral waters on oligotrophic media, higher counts than for copiotrophic compositions. Limnetic numbers inversely dipped to 4.34 × 103 CFU/mL midsummer. Cultured AAP did not follow heterotrophic trends, instead peaking during the spring in both littoral and limnetic waters as 19.1 and 4.7% of total copiotrophs, or 3.9 and 4.9% of oligotrophs, decreasing till autumn each year. Complementary observations came from environmental 16S V4 rRNA gene analysis, as AAP made up 1.49 and 1.02% of the littoral and limnetic sequenced communities in the spring, declining with seasonal progression. Spatial and temporal fluctuations of microbes compared to environmental factors exposed photosynthetic populations to independently and regularly fluctuate in the ecosystem. Oxygenic phototrophic numbers expectantly matched the midsummer peak of Chl a and b, oxygenic photosynthesis related carbon fixation, and water temperature. Independently, AAP particularly colonized spring littoral areas more than limnetic, and directly corresponded to habitat conditions that specifically promoted growth: the requirement of light and organic material.
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Block KR, O'Brien JM, Edwards WJ, Marnocha CL. Vertical structure of the bacterial diversity in meromictic Fayetteville Green Lake. Microbiologyopen 2021; 10:e1228. [PMID: 34459548 PMCID: PMC8330806 DOI: 10.1002/mbo3.1228] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/16/2021] [Accepted: 07/19/2021] [Indexed: 11/08/2022] Open
Abstract
The permanently stratified water columns in euxinic meromictic lakes produce niche environments for phototrophic sulfur oxidizers and diverse sulfur metabolisms. While Green Lake (Fayetteville, New York, NY) is known to host a diverse community of ecologically important sulfur bacteria, analyses of its microbial communities, to date, have been largely based on pigment analysis and smaller datasets from Sanger sequencing techniques. Here, we present the results of next-generation sequencing of the eubacterial community in the context of the water column geochemistry. We observed abundant purple and green sulfur bacteria, as well as anoxygenic photosynthesis-capable cyanobacteria within the upper monimolimnion. Amidst the phototrophs, we found other sulfur-cycling bacteria including sulfur disproportionators and chemotrophic sulfur oxidizers, further detailing our understanding of the sulfur cycle and microbial ecology of euxinic, meromictic lakes.
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Affiliation(s)
| | - Joy M. O'Brien
- Department of BiologyNiagara UniversityLewistonNew YorkUSA
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Exploring Viral Diversity in a Gypsum Karst Lake Ecosystem Using Targeted Single-Cell Genomics. Genes (Basel) 2021; 12:genes12060886. [PMID: 34201311 PMCID: PMC8226683 DOI: 10.3390/genes12060886] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 12/14/2022] Open
Abstract
Little is known about the diversity and distribution of viruses infecting green sulfur bacteria (GSB) thriving in euxinic (sulfuric and anoxic) habitats, including gypsum karst lake ecosystems. In this study, we used targeted cell sorting combined with single-cell sequencing to gain insights into the gene content and genomic potential of viruses infecting sulfur-oxidizing bacteria Chlorobium clathratiforme, obtained from water samples collected during summer stratification in gypsum karst Lake Kirkilai (Lithuania). In total, 82 viral contigs were bioinformatically identified in 62 single amplified genomes (SAGs) of C. clathratiforme. The majority of viral gene and protein sequences showed little to no similarity with phage sequences in public databases, uncovering the vast diversity of previously undescribed GSB viruses. We observed a high level of lysogenization in the C. clathratiforme population, as 87% SAGs contained intact prophages. Among the thirty identified auxiliary metabolic genes (AMGs), two, thiosulfate sulfurtransferase (TST) and thioredoxin-dependent phosphoadenosine phosphosulfate (PAPS) reductase (cysH), were found to be involved in the oxidation of inorganic sulfur compounds, suggesting that viruses can influence the metabolism and cycling of this essential element. Finally, the analysis of CRISPR spacers retrieved from the consensus C. clathratiforme genome imply persistent and active virus–host interactions for several putative phages prevalent among C. clathratiforme SAGs. Overall, this study provides a glimpse into the diversity of phages associated with naturally occurring and highly abundant sulfur-oxidizing bacteria.
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Berg M, Goudeau D, Olmsted C, McMahon KD, Yitbarek S, Thweatt JL, Bryant DA, Eloe-Fadrosh EA, Malmstrom RR, Roux S. Host population diversity as a driver of viral infection cycle in wild populations of green sulfur bacteria with long standing virus-host interactions. THE ISME JOURNAL 2021; 15:1569-1584. [PMID: 33452481 PMCID: PMC8163819 DOI: 10.1038/s41396-020-00870-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 09/29/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023]
Abstract
Temperate phages are viruses of bacteria that can establish two types of infection: a lysogenic infection in which the virus replicates with the host cell without producing virions, and a lytic infection where the host cell is eventually destroyed, and new virions are released. While both lytic and lysogenic infections are routinely observed in the environment, the ecological and evolutionary processes regulating these viral dynamics are still not well understood, especially for uncultivated virus-host pairs. Here, we characterized the long-term dynamics of uncultivated viruses infecting green sulfur bacteria (GSB) in a model freshwater lake (Trout Bog Lake, TBL). As no GSB virus has been formally described yet, we first used two complementary approaches to identify new GSB viruses from TBL; one in vitro based on flow cytometry cell sorting, the other in silico based on CRISPR spacer sequences. We then took advantage of existing TBL metagenomes covering the 2005-2018 period to examine the interactions between GSB and their viruses across years and seasons. From our data, GSB populations in TBL were constantly associated with at least 2-8 viruses each, including both lytic and temperate phages. The dominant GSB population in particular was consistently associated with two prophages with a nearly 100% infection rate for >10 years. We illustrate with a theoretical model that such an interaction can be stable given a low, but persistent, level of prophage induction in low-diversity host populations. Overall, our data suggest that lytic and lysogenic viruses can readily co-infect the same host population, and that host strain-level diversity might be an important factor controlling virus-host dynamics including lytic/lysogeny switch.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Simon Roux
- Joint Genome Institute, Berkeley, CA, USA.
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Garcia SL, Mehrshad M, Buck M, Tsuji JM, Neufeld JD, McMahon KD, Bertilsson S, Greening C, Peura S. Freshwater Chlorobia Exhibit Metabolic Specialization among Cosmopolitan and Endemic Populations. mSystems 2021; 6:e01196-20. [PMID: 33975970 PMCID: PMC8125076 DOI: 10.1128/msystems.01196-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 04/09/2021] [Indexed: 01/15/2023] Open
Abstract
Photosynthetic bacteria from the class Chlorobia (formerly phylum Chlorobi) sustain carbon fixation in anoxic water columns. They harvest light at extremely low intensities and use various inorganic electron donors to fix carbon dioxide into biomass. Until now, most information on the functional ecology and local adaptations of Chlorobia members came from isolates and merely 26 sequenced genomes that may not adequately represent natural populations. To address these limitations, we analyzed global metagenomes to profile planktonic Chlorobia cells from the oxyclines of 42 freshwater bodies, spanning subarctic to tropical regions and encompassing all four seasons. We assembled and compiled over 500 genomes, including metagenome-assembled genomes (MAGs), single-amplified genomes (SAGs), and reference genomes from cultures, clustering them into 71 metagenomic operational taxonomic units (mOTUs or "species"). Of the 71 mOTUs, 57 were classified within the genus Chlorobium, and these mOTUs represented up to ∼60% of the microbial communities in the sampled anoxic waters. Several Chlorobium-associated mOTUs were globally distributed, whereas others were endemic to individual lakes. Although most clades encoded the ability to oxidize hydrogen, many lacked genes for the oxidation of specific sulfur and iron substrates. Surprisingly, one globally distributed Scandinavian clade encoded the ability to oxidize hydrogen, sulfur, and iron, suggesting that metabolic versatility facilitated such widespread colonization. Overall, these findings provide new insight into the biogeography of the Chlorobia and the metabolic traits that facilitate niche specialization within lake ecosystems.IMPORTANCE The reconstruction of genomes from metagenomes has helped explore the ecology and evolution of environmental microbiota. We applied this approach to 274 metagenomes collected from diverse freshwater habitats that spanned oxic and anoxic zones, sampling seasons, and latitudes. We demonstrate widespread and abundant distributions of planktonic Chlorobia-associated bacteria in hypolimnetic waters of stratified freshwater ecosystems and show they vary in their capacities to use different electron donors. Having photoautotrophic potential, these Chlorobia members could serve as carbon sources that support metalimnetic and hypolimnetic food webs.
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Affiliation(s)
- Sarahi L Garcia
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Maliheh Mehrshad
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Moritz Buck
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Jackson M Tsuji
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Josh D Neufeld
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Katherine D McMahon
- Department of Civil and Environmental Engineering, University of Wisconsin, Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin, Madison, Madison, Wisconsin, USA
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
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Lipko IA, Belykh OI. Environmental Features of Freshwater Planktonic Actinobacteria. CONTEMP PROBL ECOL+ 2021. [DOI: 10.1134/s1995425521020074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Effects of Seasonal Anoxia on the Microbial Community Structure in Demosponges in a Marine Lake in Lough Hyne, Ireland. mSphere 2021; 6:6/1/e00991-20. [PMID: 33536324 PMCID: PMC7860989 DOI: 10.1128/msphere.00991-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Climate change is expanding marine oxygen minimum zones (OMZs), while anthropogenic nutrient input depletes oxygen concentrations locally. The effects of deoxygenation on animals are generally detrimental; however, some sponges (Porifera) exhibit hypoxic and anoxic tolerance through currently unknown mechanisms. Sponges harbor highly specific microbiomes, which can include microbes with anaerobic capabilities. Sponge-microbe symbioses must also have persisted through multiple anoxic/hypoxic periods throughout Earth's history. Since sponges lack key components of the hypoxia-inducible factor (HIF) pathway responsible for hypoxic responses in other animals, it was hypothesized that sponge tolerance to deoxygenation may be facilitated by its microbiome. To test this hypothesis, we determined the microbial composition of sponge species tolerating seasonal anoxia and hypoxia in situ in a semienclosed marine lake, using 16S rRNA amplicon sequencing. We discovered a high degree of cryptic diversity among sponge species tolerating seasonal deoxygenation, including at least nine encrusting species of the orders Axinellida and Poecilosclerida. Despite significant changes in microbial community structure in the water, sponge microbiomes were species specific and remarkably stable under varied oxygen conditions, which was further explored for Eurypon spp. 2 and Hymeraphia stellifera However, some symbiont sharing occurred under anoxia. At least three symbiont combinations, all including large populations of Thaumarchaeota, corresponded with deoxygenation tolerance, and some combinations were shared between some distantly related hosts. We propose hypothetical host-symbiont interactions following deoxygenation that could confer deoxygenation tolerance.IMPORTANCE The oceans have an uncertain future due to anthropogenic stressors and an uncertain past that is becoming clearer with advances in biogeochemistry. Both past and future oceans were, or will be, deoxygenated in comparison to present conditions. Studying how sponges and their associated microbes tolerate deoxygenation provides insights into future marine ecosystems. Moreover, sponges form the earliest branch of the animal evolutionary tree, and they likely resemble some of the first animals. We determined the effects of variable environmental oxygen concentrations on the microbial communities of several demosponge species during seasonal anoxia in the field. Our results indicate that anoxic tolerance in some sponges may depend on their symbionts, but anoxic tolerance was not universal in sponges. Therefore, some sponge species could likely outcompete benthic organisms like corals in future, reduced-oxygen ecosystems. Our results support the molecular evidence that sponges and other animals have a Neoproterozoic origin and that animal evolution was not limited by low-oxygen conditions.
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Chen M, Jiao YY, Zhang YQ, Krumholz LR, Ren JX, Li ZH, Zhao LY, Song HT, Lu JD. Succession of sulfur bacteria during decomposition of cyanobacterial bloom biomass in the shallow Lake Nanhu: An ex situ mesocosm study. CHEMOSPHERE 2020; 256:127101. [PMID: 32450355 DOI: 10.1016/j.chemosphere.2020.127101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/26/2020] [Accepted: 05/15/2020] [Indexed: 06/11/2023]
Abstract
Previous studies of the dynamics of sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) have focused on deep stratified lakes. The objective of this study is to present an in-depth investigation of the structure and dynamics of sulfur bacteria (including SRB and SOB) in the water column of shallow freshwater lakes. A cyanobacterial bloom biomass (CBB)-amended mesocosm experiment was conducted in this study, in which water was taken from a shallow eutrophic lake with sulfate levels near 40 mg L-1. Illumina sequencing was used to investigate SRB and SOB species involved in CBB decomposition and the effects of the increases in sulfate input on the water column microbial community structure. The accumulation of dissolved sulfide (∑H2S) produced by SRB during CBB decomposition stimulated the growth of SOB, and ∑H2S was then oxidized back to sulfate by SOB in the water column. Chlorobaculum sequences (the main SOB species in the study) were significantly influenced by increases in sulfate input, with relative abundance increasing approximately four-fold in treatments amended with 40 mg L-1 sulfate (referred to as 40S) when compared to the treatment without additional sulfate addition (referred to as CU). Additionally, an increase in SOB number was observed from day 26-37, concurrent with the decrease in SRB number, indicating the succession of sulfur bacteria. These findings suggest that biological sulfur oxidation and succession of sulfur bacteria occur in the water column during CBB decomposition in shallow freshwater ecosystems, and the increases in sulfate input stimulate microbial sulfur oxidation.
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Affiliation(s)
- Mo Chen
- Faculty of Resources and Environmental Science, Hubei University, Wuhan, 430062, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Yi-Ying Jiao
- Hubei Key Laboratory of Ecological Restoration for River-Lakes and Algal Utilization, College of Resources and Environmental Engineering, Hubei University of Technology, Wuhan, China
| | - Ya-Qing Zhang
- Faculty of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
| | - Lee R Krumholz
- Department of Botany & Microbiology, University of Oklahoma, Norman, OK, USA
| | - Jun-Xian Ren
- Faculty of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
| | - Zhao-Hua Li
- Faculty of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
| | - Li-Ya Zhao
- Faculty of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
| | - Hui-Ting Song
- Faculty of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
| | - Jin-Deng Lu
- Faculty of Resources and Environmental Science, Hubei University, Wuhan, 430062, China.
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Bhatnagar S, Cowley ES, Kopf SH, Pérez Castro S, Kearney S, Dawson SC, Hanselmann K, Ruff SE. Microbial community dynamics and coexistence in a sulfide-driven phototrophic bloom. ENVIRONMENTAL MICROBIOME 2020; 15:3. [PMID: 33902727 PMCID: PMC8066431 DOI: 10.1186/s40793-019-0348-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 11/25/2019] [Indexed: 05/30/2023]
Abstract
BACKGROUND Lagoons are common along coastlines worldwide and are important for biogeochemical element cycling, coastal biodiversity, coastal erosion protection and blue carbon sequestration. These ecosystems are frequently disturbed by weather, tides, and human activities. Here, we investigated a shallow lagoon in New England. The brackish ecosystem releases hydrogen sulfide particularly upon physical disturbance, causing blooms of anoxygenic sulfur-oxidizing phototrophs. To study the habitat, microbial community structure, assembly and function we carried out in situ experiments investigating the bloom dynamics over time. RESULTS Phototrophic microbial mats and permanently or seasonally stratified water columns commonly contain multiple phototrophic lineages that coexist based on their light, oxygen and nutrient preferences. We describe similar coexistence patterns and ecological niches in estuarine planktonic blooms of phototrophs. The water column showed steep gradients of oxygen, pH, sulfate, sulfide, and salinity. The upper part of the bloom was dominated by aerobic phototrophic Cyanobacteria, the middle and lower parts by anoxygenic purple sulfur bacteria (Chromatiales) and green sulfur bacteria (Chlorobiales), respectively. We show stable coexistence of phototrophic lineages from five bacterial phyla and present metagenome-assembled genomes (MAGs) of two uncultured Chlorobaculum and Prosthecochloris species. In addition to genes involved in sulfur oxidation and photopigment biosynthesis the MAGs contained complete operons encoding for terminal oxidases. The metagenomes also contained numerous contigs affiliating with Microviridae viruses, potentially affecting Chlorobi. Our data suggest a short sulfur cycle within the bloom in which elemental sulfur produced by sulfide-oxidizing phototrophs is most likely reduced back to sulfide by Desulfuromonas sp. CONCLUSIONS The release of sulfide creates a habitat selecting for anoxygenic sulfur-oxidizing phototrophs, which in turn create a niche for sulfur reducers. Strong syntrophism between these guilds apparently drives a short sulfur cycle that may explain the rapid development of the bloom. The fast growth and high biomass yield of Chlorobi-affiliated organisms implies that the studied lineages of green sulfur bacteria can thrive in hypoxic habitats. This oxygen tolerance is corroborated by oxidases found in MAGs of uncultured Chlorobi. The findings improve our understanding of the ecology and ecophysiology of anoxygenic phototrophs and their impact on the coupled biogeochemical cycles of sulfur and carbon.
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Affiliation(s)
- Srijak Bhatnagar
- Department of Biological Sciences, University of Calgary, Calgary, AB Canada
| | - Elise S. Cowley
- School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI USA
| | - Sebastian H. Kopf
- Department of Geological Sciences, University of Colorado, Boulder, CO USA
| | - Sherlynette Pérez Castro
- Ecosystems Center and J. Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA USA
| | - Sean Kearney
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Scott C. Dawson
- Department of Microbiology and Molecular Genetics, University of California Davis, Davis, CA USA
| | | | - S. Emil Ruff
- Ecosystems Center and J. Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA USA
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12
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Bacterial diversity in the water column of meromictic Lake Cadagno and evidence for seasonal dynamics. PLoS One 2018; 13:e0209743. [PMID: 30586464 PMCID: PMC6306205 DOI: 10.1371/journal.pone.0209743] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 12/11/2018] [Indexed: 11/19/2022] Open
Abstract
The meromictic Lake Cadagno is characterized by a compact chemocline with high concentrations of anoxygenic phototrophic purple and green sulfur bacteria. However, a complete picture of the bacterial diversity, and in particular of effects of seasonality and compartmentalization is missing. To characterize bacterial communities and elucidate relationships between them and their surrounding environment high-throughput 16S rRNA gene pyrosequencing was conducted. Proteobacteria, Chlorobi, Verrucomicrobia, and Actinobacteria were the dominant groups in Lake Cadagno water column. Moreover, bacterial interaction within the chemocline and between oxic and anoxic lake compartments were investigated through fluorescence in situ hybridization (FISH) and flow cytometry (FCM). The different populations of purple sulfur bacteria (PSB) and green sulfur bacteria (GSB) in the chemocline indicate seasonal dynamics of phototrophic sulfur bacteria composition. Interestingly, an exceptional bloom of a cyanobacteria population in the oxic-anoxic transition zone affected the common spatial distribution of phototrophic sulfur bacteria with consequence on chemocline location and water column stability. Our study suggests that both bacterial interactions between different lake compartments and within the chemocline can be a dynamic process influencing the stratification structure of Lake Cadagno water column.
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Matyugina E, Belkova N, Borzenko S, Lukyanov P, Kabilov M, Baturina O, Kley AMV, Nalian A, Ptitsyn A. Structure and diversity dynamics of microbial communities at day and night: investigation of meromictic Lake Doroninskoe, Transbaikalia, Russia. JOURNAL OF OCEANOLOGY AND LIMNOLOGY 2018; 36:1978-1992. [DOI: 10.1007/s00343-018-7332-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 03/27/2018] [Indexed: 07/26/2024]
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14
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Danza F, Storelli N, Roman S, Lüdin S, Tonolla M. Dynamic cellular complexity of anoxygenic phototrophic sulfur bacteria in the chemocline of meromictic Lake Cadagno. PLoS One 2017; 12:e0189510. [PMID: 29245157 PMCID: PMC5731995 DOI: 10.1371/journal.pone.0189510] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/28/2017] [Indexed: 11/23/2022] Open
Abstract
The meromictic Lake Cadagno is characterized by a compact chemocline with high concentrations of anoxygenic phototrophic purple sulfur bacteria (PSB) and green sulfur bacteria (GSB). The co-occurrence of phylogenetically distant bacterial groups such as PSB and GSB in the same ecological niche, makes the chemocline of Lake Cadagno an ideal system for studying the conditions and consequences of coexistence of photosynthetic bacteria populations. In this study, we applied flow cytometry (FCM) as a fast tool to identify metabolic changes due to the production and consumption of inclusion bodies such as sulfur globules (SGBs), and follow population dynamics of closely related anoxygenic photosynthetic sulfur bacteria in their natural environment. Large-celled PSB Chromatium okenii and GSB Chlorobium populations were reliably separated and identified due to differences in auto-fluorescence and cell size. Moreover, we showed that these dominant taxa share the same ecological niche over seasonal periods. Taking advantage of FCM detection of dynamic cellular complexity variation during phases of photosynthetic activity, we identified an unexpected alternation in PSB versus GSB metabolic activity, indicating dynamic interspecific interactions between these two populations.
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Affiliation(s)
- Francesco Danza
- Laboratory of Applied Microbiology (LMA), Department for Environmental Constructions and Design (DACD), University of Applied Sciences and Arts of Southern Switzerland (SUPSI), via Mirasole 22a, Bellinzona, Switzerland
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Nicola Storelli
- Laboratory of Applied Microbiology (LMA), Department for Environmental Constructions and Design (DACD), University of Applied Sciences and Arts of Southern Switzerland (SUPSI), via Mirasole 22a, Bellinzona, Switzerland
| | - Samuele Roman
- Laboratory of Applied Microbiology (LMA), Department for Environmental Constructions and Design (DACD), University of Applied Sciences and Arts of Southern Switzerland (SUPSI), via Mirasole 22a, Bellinzona, Switzerland
- Alpine Biology Center Foundation, via Mirasole 22a, Bellinzona, Switzerland
| | - Samuel Lüdin
- Laboratory of Applied Microbiology (LMA), Department for Environmental Constructions and Design (DACD), University of Applied Sciences and Arts of Southern Switzerland (SUPSI), via Mirasole 22a, Bellinzona, Switzerland
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
- Federal Office for Civil Protection, Spiez Laboratory, Biology Division, Spiez, Switzerland
| | - Mauro Tonolla
- Laboratory of Applied Microbiology (LMA), Department for Environmental Constructions and Design (DACD), University of Applied Sciences and Arts of Southern Switzerland (SUPSI), via Mirasole 22a, Bellinzona, Switzerland
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
- Alpine Biology Center Foundation, via Mirasole 22a, Bellinzona, Switzerland
- * E-mail:
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15
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Posth NR, Bristow LA, Cox RP, Habicht KS, Danza F, Tonolla M, Frigaard NU, Canfield DE. Carbon isotope fractionation by anoxygenic phototrophic bacteria in euxinic Lake Cadagno. GEOBIOLOGY 2017; 15:798-816. [PMID: 28866873 DOI: 10.1111/gbi.12254] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 07/14/2017] [Indexed: 06/07/2023]
Abstract
Anoxygenic phototrophic bacteria utilize ancient metabolic pathways to link sulfur and iron metabolism to the reduction of CO2 . In meromictic Lake Cadagno, Switzerland, both purple sulfur (PSB) and green sulfur anoxygenic phototrophic bacteria (GSB) dominate the chemocline community and drive the sulfur cycle. PSB and GSB fix carbon utilizing different enzymatic pathways and these fractionate C-isotopes to different extents. Here, these differences in C-isotope fractionation are used to constrain the relative input of various anoxygenic phototrophs to the bulk community C-isotope signal in the chemocline. We sought to determine whether a distinct isotopic signature of GSB and PSB in the chemocline persists in the settling fraction and in the sediment. To answer these questions, we also sought investigated C-isotope fractionation in the water column, settling material, and sediment of Lake Cadagno, compared these values to C-isotope fractionation of isolated anoxygenic phototroph cultures, and took a mass balance approach to investigate relative contributions to the bulk fractionation signature. We found a large C-isotope fractionation between dissolved inorganic carbon (DIC) and particulate organic carbon (POC) in the Lake Cadagno chemocline. This large fractionation between the DIC and POC was also found in culture experiments carried out with anoxygenic phototrophic bacteria isolated from the lake. In the Lake Cadagno chemocline, anoxygenic phototrophic bacteria controlled the bulk C-isotope fractionation, but the influence of GSB and PSB differed with season. Furthermore, the contribution of PSB and GSB to bulk C-isotope fractionation in the chemocline could be traced in the settling fraction and in the sediment. Taken together with other studies, such as lipid biomarker analyzes and investigations of other stratified lakes, these results offer a firmer understanding of diagenetic influences on bacterial biomass.
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Affiliation(s)
- N R Posth
- Department of Biology, Nordic Centre for Earth Evolution (Nordcee), University of Southern Denmark, Odense M, Denmark
| | - L A Bristow
- Department of Biology, Nordic Centre for Earth Evolution (Nordcee), University of Southern Denmark, Odense M, Denmark
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - R P Cox
- Department of Biology, Nordic Centre for Earth Evolution (Nordcee), University of Southern Denmark, Odense M, Denmark
| | - K S Habicht
- Department of Biology, Nordic Centre for Earth Evolution (Nordcee), University of Southern Denmark, Odense M, Denmark
- Unisense A/S, Aarhus N, Denmark
| | - F Danza
- Laboratory of Applied Microbiology, University of Applied Sciences Southern Switzerland, Bellinzona, Switzerland
- Department of Botany and Plant Biology, Microbiology Unit, University of Geneva, Geneva, Switzerland
| | - M Tonolla
- Laboratory of Applied Microbiology, University of Applied Sciences Southern Switzerland, Bellinzona, Switzerland
- Department of Botany and Plant Biology, Microbiology Unit, University of Geneva, Geneva, Switzerland
- Alpine Biology Center Foundation, Bellinzona, Switzerland
| | - N-U Frigaard
- Department of Biology, Section for Marine Biology, University of Copenhagen, Helsingør, Denmark
| | - D E Canfield
- Department of Biology, Nordic Centre for Earth Evolution (Nordcee), University of Southern Denmark, Odense M, Denmark
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16
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Thompson KJ, Simister RL, Hahn AS, Hallam SJ, Crowe SA. Nutrient Acquisition and the Metabolic Potential of Photoferrotrophic Chlorobi. Front Microbiol 2017; 8:1212. [PMID: 28729857 PMCID: PMC5498476 DOI: 10.3389/fmicb.2017.01212] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 06/14/2017] [Indexed: 11/18/2022] Open
Abstract
Anoxygenic photosynthesis evolved prior to oxygenic photosynthesis and harnessed energy from sunlight to support biomass production on the early Earth. Models that consider the availability of electron donors predict that anoxygenic photosynthesis using Fe(II), known as photoferrotrophy, would have supported most global primary production before the proliferation of oxygenic phototrophs at approximately 2.3 billion years ago. These photoferrotrophs have also been implicated in the deposition of banded iron formations, the world's largest sedimentary iron ore deposits that formed mostly in late Archean and early Proterozoic Eons. In this work we present new data and analyses that illuminate the metabolic capacity of photoferrotrophy in the phylum Chlorobi. Our laboratory growth experiments and biochemical analyses demonstrate that photoferrotrophic Chlorobi are capable of assimilatory sulfate reduction and nitrogen fixation under sulfate and nitrogen limiting conditions, respectively. Furthermore, the evolutionary histories of key enzymes in both sulfur (CysH and CysD) and nitrogen fixation (NifDKH) pathways are convoluted; protein phylogenies, however, suggest that early Chlorobi could have had the capacity to assimilate sulfur and fix nitrogen. We argue, then, that the capacity for photoferrotrophic Chlorobi to acquire these key nutrients enabled them to support primary production and underpin global biogeochemical cycles in the Precambrian.
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Affiliation(s)
- Katharine J. Thompson
- Department of Microbiology and Immunology, University of British Columbia, VancouverBC, Canada
| | - Rachel L. Simister
- Department of Microbiology and Immunology, University of British Columbia, VancouverBC, Canada
| | - Aria S. Hahn
- Department of Microbiology and Immunology, University of British Columbia, VancouverBC, Canada
| | - Steven J. Hallam
- Department of Microbiology and Immunology, University of British Columbia, VancouverBC, Canada
| | - Sean A. Crowe
- Department of Microbiology and Immunology, University of British Columbia, VancouverBC, Canada
- Departments of Earth, Ocean and Atmospheric Sciences, University of British Columbia, VancouverBC, Canada
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Savvichev AS, Kokryatskaya NM, Zabelina SA, Rusanov II, Zakharova EE, Veslopolova EF, Lunina ON, Patutina EO, Bumazhkin BK, Gruzdev DS, Sigalevich PA, Pimenov NV, Kuznetsov BB, Gorlenko VM. Microbial processes of the carbon and sulfur cycles in an ice-covered, iron-rich meromictic lake Svetloe (Arkhangelsk region, Russia). Environ Microbiol 2016; 19:659-672. [PMID: 27862807 DOI: 10.1111/1462-2920.13591] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 10/28/2016] [Indexed: 12/01/2022]
Abstract
Biogeochemical, isotope geochemical and microbiological investigation of Lake Svetloe (White Sea basin), a meromictic freshwater was carried out in April 2014, when ice thickness was ∼0.5 m, and the ice-covered water column contained oxygen to 23 m depth. Below, the anoxic water column contained ferrous iron (up to 240 μμM), manganese (60 μM), sulfide (up to 2 μM) and dissolved methane (960 μM). The highest abundance of microbial cells revealed by epifluorescence microscopy was found in the chemocline (redox zone) at 23-24.5 m. Oxygenic photosynthesis exhibited two peaks: the major one (0.43 μmol C L-1 day-1 ) below the ice and the minor one in the chemocline zone, where cyanobacteria related to Synechococcus rubescens were detected. The maximum of anoxygenic photosynthesis (0.69 μmol C L-1 day-1 ) at the oxic/anoxic interface, for which green sulfur bacteria Chlorobium phaeoclathratiforme were probably responsible, exceeded the value for oxygenic photosynthesis. Bacterial sulfate reduction peaked (1.5 μmol S L-1 day-1 ) below the chemocline zone. The rates of methane oxidation were as high as 1.8 μmol CH4 L-1 day-1 at the oxi/anoxic interface and much lower in the oxic zone. Small phycoerythrin-containing Synechococcus-related cyanobacteria were probably involved in accumulation of metal oxides in the redox zone.
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Affiliation(s)
- Alexander S Savvichev
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Natalia M Kokryatskaya
- Institute of Ecological Problems of the North, Ural Branch, Russian Academy of Sciences, Arkhangelsk, Russia
| | - Svetlana A Zabelina
- Institute of Ecological Problems of the North, Ural Branch, Russian Academy of Sciences, Arkhangelsk, Russia
| | - Igor I Rusanov
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Elena E Zakharova
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Elena F Veslopolova
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Olga N Lunina
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina O Patutina
- Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Boris K Bumazhkin
- Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Denis S Gruzdev
- Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Pavel A Sigalevich
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Nikolay V Pimenov
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Boris B Kuznetsov
- Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Vladimir M Gorlenko
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
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18
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Speciation and ecological success in dimly lit waters: horizontal gene transfer in a green sulfur bacteria bloom unveiled by metagenomic assembly. ISME JOURNAL 2016; 11:201-211. [PMID: 27392085 DOI: 10.1038/ismej.2016.93] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 05/06/2016] [Accepted: 06/07/2016] [Indexed: 01/08/2023]
Abstract
A natural planktonic bloom of a brown-pigmented photosynthetic green sulfur bacteria (GSB) from the disphotic zone of karstic Lake Banyoles (NE Spain) was studied as a natural enrichment culture from which a nearly complete genome was obtained after metagenomic assembly. We showed in situ a case where horizontal gene transfer (HGT) explained the ecological success of a natural population unveiling ecosystem-specific adaptations. The uncultured brown-pigmented GSB was 99.7% identical in the 16S rRNA gene sequence to its green-pigmented cultured counterpart Chlorobium luteolum DSM 273T. Several differences were detected for ferrous iron acquisition potential, ATP synthesis and gas vesicle formation, although the most striking trait was related to pigment biosynthesis strategy. Chl. luteolum DSM 273T synthesizes bacteriochlorophyll (BChl) c, whereas Chl. luteolum CIII incorporated by HGT a 18-kbp cluster with the genes needed for BChl e and specific carotenoids biosynthesis that provided ecophysiological advantages to successfully colonize the dimly lit waters. We also genomically characterized what we believe to be the first described GSB phage, which based on the metagenomic coverage was likely in an active state of lytic infection. Overall, we observed spread HGT and we unveiled clear evidence for virus-mediated HGT in a natural population of photosynthetic GSB.
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19
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Hamilton TL, Bovee RJ, Sattin SR, Mohr W, Gilhooly WP, Lyons TW, Pearson A, Macalady JL. Carbon and Sulfur Cycling below the Chemocline in a Meromictic Lake and the Identification of a Novel Taxonomic Lineage in the FCB Superphylum, Candidatus Aegiribacteria. Front Microbiol 2016; 7:598. [PMID: 27199928 PMCID: PMC4846661 DOI: 10.3389/fmicb.2016.00598] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/11/2016] [Indexed: 11/13/2022] Open
Abstract
Mahoney Lake in British Columbia is an extreme meromictic system with unusually high levels of sulfate and sulfide present in the water column. As is common in strongly stratified lakes, Mahoney Lake hosts a dense, sulfide-oxidizing phototrophic microbial community where light reaches the chemocline. Below this "plate," the euxinic hypolimnion is anoxic, eutrophic, saline, and rich in sulfide, polysulfides, elemental sulfur, and other sulfur intermediates. While much is known regarding microbial communities in sunlit portions of euxinic systems, the composition and genetic potential of organisms living at aphotic depths have rarely been studied. Metagenomic sequencing of samples from the hypolimnion and the underlying sediments of Mahoney Lake indicate that multiple taxa contribute to sulfate reduction below the chemocline and that the hypolimnion and sediments each support distinct populations of sulfate reducing bacteria (SRB) that differ from the SRB populations observed in the chemocline. After assembling and binning the metagenomic datasets, we recovered near-complete genomes of dominant populations including two Deltaproteobacteria. One of the deltaproteobacterial genomes encoded a 16S rRNA sequence that was most closely related to the sulfur-disproportionating genus Dissulfuribacter and the other encoded a 16S rRNA sequence that was most closely related to the fatty acid- and aromatic acid-degrading genus Syntrophus. We also recovered two near-complete genomes of Firmicutes species. Analysis of concatenated ribosomal protein trees suggests these genomes are most closely related to extremely alkaliphilic genera Alkaliphilus and Dethiobacter. Our metagenomic data indicate that these Firmicutes contribute to carbon cycling below the chemocline. Lastly, we recovered a nearly complete genome from the sediment metagenome which represents a new genus within the FCB (Fibrobacteres, Chlorobi, Bacteroidetes) superphylum. Consistent with the geochemical data, we found little or no evidence for organisms capable of sulfide oxidation in the aphotic zone below the chemocline. Instead, comparison of functional genes below the chemocline are consistent with recovery of multiple populations capable of reducing oxidized sulfur. Our data support previous observations that at least some of the sulfide necessary to support the dense population of phototrophs in the chemocline is supplied from sulfate reduction in the hypolimnion and sediments. These studies provide key insights regarding the taxonomic and functional diversity within a euxinic environment and highlight the complexity of biogeochemical carbon and sulfur cycling necessary to maintain euxinia.
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Affiliation(s)
- Trinity L Hamilton
- Department of Biological Sciences, University of Cincinnati Cincinnati, OH, USA
| | - Roderick J Bovee
- Department of Earth and Planetary Sciences, Harvard University Cambridge, MA, USA
| | - Sarah R Sattin
- Department of Earth and Planetary Sciences, Harvard University Cambridge, MA, USA
| | - Wiebke Mohr
- Department of Earth and Planetary Sciences, Harvard University Cambridge, MA, USA
| | - William P Gilhooly
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis Indianapolis, IN, USA
| | - Timothy W Lyons
- Department of Earth Sciences, University of California Riverside, CA, USA
| | - Ann Pearson
- Department of Earth and Planetary Sciences, Harvard University Cambridge, MA, USA
| | - Jennifer L Macalady
- Penn State Astrobiology Research Center, Department of Geosciences, Pennsylvania State University University Park, TX, USA
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20
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Baatar B, Chiang PW, Rogozin DY, Wu YT, Tseng CH, Yang CY, Chiu HH, Oyuntsetseg B, Degermendzhy AG, Tang SL. Bacterial Communities of Three Saline Meromictic Lakes in Central Asia. PLoS One 2016; 11:e0150847. [PMID: 26934492 PMCID: PMC4775032 DOI: 10.1371/journal.pone.0150847] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 02/19/2016] [Indexed: 12/20/2022] Open
Abstract
Meromictic lakes located in landlocked steppes of central Asia (~2500 km inland) have unique geophysiochemical characteristics compared to other meromictic lakes. To characterize their bacteria and elucidate relationships between those bacteria and surrounding environments, water samples were collected from three saline meromictic lakes (Lakes Shira, Shunet and Oigon) in the border between Siberia and the West Mongolia, near the center of Asia. Based on in-depth tag pyrosequencing, bacterial communities were highly variable and dissimilar among lakes and between oxic and anoxic layers within individual lakes. Proteobacteria, Bacteroidetes, Cyanobacteria, Actinobacteria and Firmicutes were the most abundant phyla, whereas three genera of purple sulfur bacteria (a novel genus, Thiocapsa and Halochromatium) were predominant bacterial components in the anoxic layer of Lake Shira (~20.6% of relative abundance), Lake Shunet (~27.1%) and Lake Oigon (~9.25%), respectively. However, few known green sulfur bacteria were detected. Notably, 3.94% of all sequencing reads were classified into 19 candidate divisions, which was especially high (23.12%) in the anoxic layer of Lake Shunet. Furthermore, several hydro-parameters (temperature, pH, dissolved oxygen, H2S and salinity) were associated (P< 0.05) with variations in dominant bacterial groups. In conclusion, based on highly variable bacterial composition in water layers or lakes, we inferred that the meromictic ecosystem was characterized by high diversity and heterogenous niches.
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Affiliation(s)
- Bayanmunkh Baatar
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan
| | - Pei-Wen Chiang
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Yu-Ting Wu
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
- National Pingtung University of Science and Technology, Pingtung, Taiwan
| | | | - Cheng-Yu Yang
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Hsiu-Hui Chiu
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Bolormaa Oyuntsetseg
- School of Art and Sciences, National University of Mongolia, Ulaanbaatar 14201, Mongolia
| | | | - Sen-Lin Tang
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung, Taiwan
- * E-mail:
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21
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Biderre-Petit C, Dugat-Bony E, Mege M, Parisot N, Adrian L, Moné A, Denonfoux J, Peyretaillade E, Debroas D, Boucher D, Peyret P. Distribution of Dehalococcoidia in the Anaerobic Deep Water of a Remote Meromictic Crater Lake and Detection of Dehalococcoidia-Derived Reductive Dehalogenase Homologous Genes. PLoS One 2016; 11:e0145558. [PMID: 26734727 PMCID: PMC4703385 DOI: 10.1371/journal.pone.0145558] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/04/2015] [Indexed: 12/29/2022] Open
Abstract
Here we describe the natural occurrence of bacteria of the class Dehalococcoidia (DEH) and their diversity at different depths in anoxic waters of a remote meromictic lake (Lake Pavin) using 16S rRNA gene amplicon sequencing and quantitative PCR. Detected DEH are phylogenetically diverse and the majority of 16S rRNA sequences have less than 91% similarity to previously isolated DEH 16S rRNA sequences. To predict the metabolic potential of detected DEH subgroups and to assess if they encode genes to transform halogenated compounds, we enriched DEH-affiliated genomic DNA by using a specific-gene capture method and probes against DEH-derived 16S rRNA genes, reductive dehalogenase genes and known insertion sequences. Two reductive dehalogenase homologous sequences were identified from DEH-enriched genomic DNA, and marker genes in the direct vicinity confirm that gene fragments were derived from DEH. The low sequence similarity with known reductive dehalogenase genes suggests yet-unknown catabolic potential in the anoxic zone of Lake Pavin.
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Affiliation(s)
- Corinne Biderre-Petit
- Laboratoire “Microorganismes: Génome et Environnement,” Clermont Université, Université Blaise Pascal, F-63000, Clermont-Ferrand, France
- Laboratoire Microorganismes, Génome et Environnement, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 6023, F-63171, Aubière, France
- * E-mail:
| | - Eric Dugat-Bony
- UMR GMPA, AgroParisTech, INRA, Université Paris-Saclay, 78850, Thiverval-Grignon, France
| | - Mickaël Mege
- Laboratoire “Microorganismes: Génome et Environnement,” Clermont Université, Université Blaise Pascal, F-63000, Clermont-Ferrand, France
- Laboratoire Microorganismes, Génome et Environnement, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 6023, F-63171, Aubière, France
| | - Nicolas Parisot
- Laboratoire “Microorganismes: Génome et Environnement,” Clermont Université, Université Blaise Pascal, F-63000, Clermont-Ferrand, France
- Laboratoire Microorganismes, Génome et Environnement, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 6023, F-63171, Aubière, France
- Clermont Université, Université d’Auvergne, EA 4678 CIDAM, BP 10448, F-63001, Clermont-Ferrand, France
| | - Lorenz Adrian
- Helmholtz Centre for Environmental Research–UFZ, Permoserstraße 15, D-04318, Leipzig, Germany
| | - Anne Moné
- Laboratoire “Microorganismes: Génome et Environnement,” Clermont Université, Université Blaise Pascal, F-63000, Clermont-Ferrand, France
- Laboratoire Microorganismes, Génome et Environnement, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 6023, F-63171, Aubière, France
| | - Jérémie Denonfoux
- Clermont Université, Université d’Auvergne, EA 4678 CIDAM, BP 10448, F-63001, Clermont-Ferrand, France
| | - Eric Peyretaillade
- Clermont Université, Université d’Auvergne, EA 4678 CIDAM, BP 10448, F-63001, Clermont-Ferrand, France
| | - Didier Debroas
- Laboratoire “Microorganismes: Génome et Environnement,” Clermont Université, Université Blaise Pascal, F-63000, Clermont-Ferrand, France
- Laboratoire Microorganismes, Génome et Environnement, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 6023, F-63171, Aubière, France
| | - Delphine Boucher
- Clermont Université, Université d’Auvergne, EA 4678 CIDAM, BP 10448, F-63001, Clermont-Ferrand, France
| | - Pierre Peyret
- Clermont Université, Université d’Auvergne, EA 4678 CIDAM, BP 10448, F-63001, Clermont-Ferrand, France
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Community shift from phototrophic to chemotrophic sulfide oxidation following anoxic holomixis in a stratified seawater lake. Appl Environ Microbiol 2014; 81:298-308. [PMID: 25344237 DOI: 10.1128/aem.02435-14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Most stratified sulfidic holomictic lakes become oxygenated after annual turnover. In contrast, Lake Rogoznica, on the eastern Adriatic coast, has been observed to undergo a period of water column anoxia after water layer mixing and establishment of holomictic conditions. Although Lake Rogoznica's chemistry and hydrography have been studied extensively, it is unclear how the microbial communities typically inhabiting the oxic epilimnion and a sulfidic hypolimnion respond to such a drastic shift in redox conditions. We investigated the impact of anoxic holomixis on microbial diversity and microbially mediated sulfur cycling in Lake Rogoznica with an array of culture-independent microbiological methods. Our data suggest a tight coupling between the lake's chemistry and occurring microorganisms. During stratification, anoxygenic phototrophic sulfur bacteria were dominant at the chemocline and in the hypolimnion. After an anoxic mixing event, the anoxygenic phototrophic sulfur bacteria entirely disappeared, and the homogeneous, anoxic water column was dominated by a bloom of gammaproteobacterial sulfur oxidizers related to the GSO/SUP05 clade. This study is the first report of a community shift from phototrophic to chemotrophic sulfide oxidizers as a response to anoxic holomictic conditions in a seasonally stratified seawater lake.
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Hamilton TL, Bovee RJ, Thiel V, Sattin SR, Mohr W, Schaperdoth I, Vogl K, Gilhooly WP, Lyons TW, Tomsho LP, Schuster SC, Overmann J, Bryant DA, Pearson A, Macalady JL. Coupled reductive and oxidative sulfur cycling in the phototrophic plate of a meromictic lake. GEOBIOLOGY 2014; 12:451-68. [PMID: 24976102 DOI: 10.1111/gbi.12092] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 05/30/2014] [Indexed: 05/10/2023]
Abstract
Mahoney Lake represents an extreme meromictic model system and is a valuable site for examining the organisms and processes that sustain photic zone euxinia (PZE). A single population of purple sulfur bacteria (PSB) living in a dense phototrophic plate in the chemocline is responsible for most of the primary production in Mahoney Lake. Here, we present metagenomic data from this phototrophic plate--including the genome of the major PSB, as obtained from both a highly enriched culture and from the metagenomic data--as well as evidence for multiple other taxa that contribute to the oxidative sulfur cycle and to sulfate reduction. The planktonic PSB is a member of the Chromatiaceae, here renamed Thiohalocapsa sp. strain ML1. It produces the carotenoid okenone, yet its closest relatives are benthic PSB isolates, a finding that may complicate the use of okenone (okenane) as a biomarker for ancient PZE. Favorable thermodynamics for non-phototrophic sulfide oxidation and sulfate reduction reactions also occur in the plate, and a suite of organisms capable of oxidizing and reducing sulfur is apparent in the metagenome. Fluctuating supplies of both reduced carbon and reduced sulfur to the chemocline may partly account for the diversity of both autotrophic and heterotrophic species. Collectively, the data demonstrate the physiological potential for maintaining complex sulfur and carbon cycles in an anoxic water column, driven by the input of exogenous organic matter. This is consistent with suggestions that high levels of oxygenic primary production maintain episodes of PZE in Earth's history and that such communities should support a diversity of sulfur cycle reactions.
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Affiliation(s)
- T L Hamilton
- Department of Geosciences, Penn State Astrobiology Research Center (PSARC), The Pennsylvania State University, University Park, PA, USA
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24
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Abstract
Despite recent advances in metagenomic and single-cell genomic sequencing to investigate uncultivated microbial diversity and metabolic potential, fundamental questions related to population structure, interactions, and biogeochemical roles of candidate divisions remain. Numerous molecular surveys suggest that stratified ecosystems manifesting anoxic, sulfidic, and/or methane-rich conditions are enriched in these enigmatic microbes. Here we describe diversity, abundance, and cooccurrence patterns of uncultivated microbial communities inhabiting the permanently stratified waters of meromictic Sakinaw Lake, British Columbia, Canada, using 454 sequencing of the small-subunit rRNA gene with three-domain resolution. Operational taxonomic units (OTUs) were affiliated with 64 phyla, including more than 25 candidate divisions. Pronounced trends in community structure were observed for all three domains with eukaryotic sequences vanishing almost completely below the mixolimnion, followed by a rapid and sustained increase in methanogen-affiliated (∼10%) and unassigned (∼60%) archaeal sequences as well as bacterial OTUs affiliated with Chloroflexi (∼22%) and candidate divisions (∼28%). Network analysis revealed highly correlated, depth-dependent cooccurrence patterns between Chloroflexi, candidate divisions WWE1, OP9/JS1, OP8, and OD1, methanogens, and unassigned archaeal OTUs indicating niche partitioning and putative syntrophic growth modes. Indeed, pathway reconstruction using recently published Sakinaw Lake single-cell genomes affiliated with OP9/JS1 and OP8 revealed complete coverage of the Wood-Ljungdahl pathway with potential to drive syntrophic acetate oxidation to hydrogen and carbon dioxide under methanogenic conditions. Taken together, these observations point to previously unrecognized syntrophic networks in meromictic lake ecosystems with the potential to inform design and operation of anaerobic methanogenic bioreactors.
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25
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Mori Y, Kataoka T, Okamura T, Kondo R. Dominance of green sulfur bacteria in the chemocline of the meromictic Lake Suigetsu, Japan, as revealed by dissimilatory sulfite reductase gene analysis. Arch Microbiol 2013; 195:303-12. [PMID: 23455488 DOI: 10.1007/s00203-013-0879-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 12/18/2012] [Accepted: 02/16/2013] [Indexed: 10/27/2022]
Abstract
This study investigated the spatiotemporal abundance and diversity of the α-subunit of the dissimilatory sulfite reductase gene (dsrA) in the meromictic Lake Suigetsu for assessing the sulfur-oxidizing bacterial community. The density of dsrA in the chemocline reached up to 3.1 × 10(6) copies ml(-1) in summer by means of quantitative real-time PCR and it was generally higher than deeper layers. Most of the dsrA clones sequenced were related to green sulfur bacteria such as Chlorobium phaeovibrioides, C. limicola, and C. luteolum. Below the chemocline of the lake, we also detected other dsrA clones related to the purple sulfur bacterium Halochromatium salexigens and some branching lineages of diverse sequences that were related to chemotrophic sulfur bacterial species such as Magnetospirillum gryphiswaldense, Candidatus Ruthia magnifica, and Candidatus Thiobios zoothamnicoli. The abundance and community compositions of sulfur-oxidizing bacteria changed depending on the water depth and season. This study indicated that the green sulfur bacteria dominated among sulfur-oxidizing bacterial population in the chemocline of Lake Suigetsu and that certain abiotic environmental variables were important factors that determined sulfur bacterial abundance and community structure.
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Affiliation(s)
- Yumi Mori
- Department of Marine Bioscience, Fukui Prefectural University, Obama, Fukui 917-0003, Japan.
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26
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Storelli N, Peduzzi S, Saad MM, Frigaard NU, Perret X, Tonolla M. CO2assimilation in the chemocline of Lake Cadagno is dominated by a few types of phototrophic purple sulfur bacteria. FEMS Microbiol Ecol 2013; 84:421-32. [DOI: 10.1111/1574-6941.12074] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
| | | | - Maged M. Saad
- Department of Botany and Plant Biology, Microbiology Unit; University of Geneva, Sciences III; Geneva; Switzerland
| | - Niels-Ulrik Frigaard
- Section for Marine Biology, Department of Biology; University of Copenhagen; Helsingør; Denmark
| | - Xavier Perret
- Department of Botany and Plant Biology, Microbiology Unit; University of Geneva, Sciences III; Geneva; Switzerland
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27
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Edberg F, Andersson AF, Holmström SJM. Bacterial community composition in the water column of a lake formed by a former uranium open pit mine. MICROBIAL ECOLOGY 2012; 64:870-880. [PMID: 22622763 DOI: 10.1007/s00248-012-0069-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 04/27/2012] [Indexed: 06/01/2023]
Abstract
Mining of pyrite minerals is a major environmental issue involving both biological and geochemical processes. Here we present a study of an artificial lake of a former uranium open pit mine with the aim to connect the chemistry and bacterial community composition (454-pyrosequencing of 16S rRNA genes) in the stratified water column. A shift in the water chemistry from oxic conditions in the epilimnion to anoxic, alkaline, and metal and sulfide-rich conditions in the hypolimnion was corresponded by a strong shift in the bacterial community, with few shared operational taxonomic units (OTU) between the water layers. The epilimnetic bacterial community of the lake (~20 years old) showed similarities to other temperate freshwater lakes, while the hypolimnetic bacterial community showed similarity to extreme chemical environments. The epilimnetic bacterial community had dominance of Actinobacteria and Betaproteobacteria. The hypolimnion displayed a higher bacterial diversity and was dominated by the phototrophic green sulphur bacterium of the genus Chlorobium (ca. 40 % of the total community). Deltaproteobacteria were only represented in the hypolimnion and the most abundant OTUs were affiliated with ferric iron and sulfate reducers of the genus Geobacter and Desulfobulbus, respectively. The chemistry is clearly controlling, especially the hypolimnetic, bacterial community but the community composition also indicates that the bacteria are involved in metal cycling in the lake.
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Affiliation(s)
- Frida Edberg
- Department of Applied Environmental Science, Stockholm University, 106 91 Stockholm, Sweden
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28
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Vertical distribution of microbial communities in a perennially stratified Arctic lake with saline, anoxic bottom waters. Sci Rep 2012; 2:604. [PMID: 22930670 PMCID: PMC3428602 DOI: 10.1038/srep00604] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 08/09/2012] [Indexed: 11/25/2022] Open
Abstract
Meromictic lakes are useful biogeochemical models because of their stratified chemical gradients and separation of redox reactions down the water column. Perennially ice-covered meromictic lakes are particularly stable, with long term constancy in their density profiles. Here we sampled Lake A, a deep meromictic lake at latitude 83°N in High Arctic Canada. Sampling was before (May) and after (August) an unusual ice-out event during the warm 2008 summer. We determined the bacterial and archaeal community composition by high-throughput 16S rRNA gene tag-pyrosequencing. Both prokaryote communities were stratified by depth and the Bacteria differed between dates, indicating locally driven selection processes. We matched taxa to known taxon-specific biogeochemical functions and found a close correspondence between the depth of functional specialists and chemical gradients. These results indicate a rich microbial diversity despite the extreme location, with pronounced vertical structure in taxonomic and potential functional composition, and with community shifts during ice-out.
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29
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Archaeal diversity: temporal variation in the arsenic-rich creek sediments of Carnoulès Mine, France. Extremophiles 2012; 16:645-57. [PMID: 22714283 DOI: 10.1007/s00792-012-0466-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 05/03/2012] [Indexed: 02/01/2023]
Abstract
The Carnoulès mine is an extreme environment located in the South of France. It is an unusual ecosystem due to its acidic pH (2-3), high concentration of heavy metals, iron, and sulfate, but mainly due to its very high concentration of arsenic (up to 10 g L⁻¹ in the tailing stock pore water, and 100-350 mg L⁻¹ in Reigous Creek, which collects the acid mine drainage). Here, we present a survey of the archaeal community in the sediment and its temporal variation using a culture-independent approach by cloning of 16S rRNA encoding genes. The taxonomic affiliation of Archaea showed a low degree of biodiversity with two different phyla: Euryarchaeota and Thaumarchaeota. The archaeal community varied in composition and richness throughout the sampling campaigns. Many sequences were phylogenetically related to the order Thermoplasmatales represented by aerobic or facultatively anaerobic, thermoacidophilic autotrophic or heterotrophic organisms like the organotrophic genus Thermogymnomonas. Some members of Thermoplasmatales can also derive energy from sulfur/iron oxidation or reduction. We also found microorganisms affiliated with methanogenic Archaea (Methanomassiliicoccus luminyensis), which are involved in the carbon cycle. Some sequences affiliated with ammonia oxidizers, involved in the first and rate-limiting step in nitrification, a key process in the nitrogen cycle were also observed, including Candidatus Nitrososphaera viennensis and Candidatus nitrosopumilus sp. These results suggest that Archaea may be important players in the Reigous sediments through their participation in the biochemical cycles of elements, including those of carbon and nitrogen.
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30
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Ravasi DF, Peduzzi S, Guidi V, Peduzzi R, Wirth SB, Gilli A, Tonolla M. Development of a real-time PCR method for the detection of fossil 16S rDNA fragments of phototrophic sulfur bacteria in the sediments of Lake Cadagno. GEOBIOLOGY 2012; 10:196-204. [PMID: 22433067 DOI: 10.1111/j.1472-4669.2012.00326.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Lake Cadagno is a crenogenic meromictic lake situated in the southern range of the Swiss Alps characterized by a compact chemocline that has been the object of many ecological studies. The population dynamics of phototrophic sulfur bacteria in the chemocline has been monitored since 1994 with molecular methods such as 16S rRNA gene clone library analysis. To reconstruct paleo-microbial community dynamics, we developed a quantitative real-time PCR methodology for specific detection of 16S rRNA gene sequences of purple and green sulfur bacteria populations from sediment samples. We detected fossil 16S rDNA of nine populations of phototrophic sulfur bacteria down to 9-m sediment depth, corresponding to about 9500 years of the lake's biogeological history. These results provide the first evidence for the presence of 16S rDNA of anoxygenic phototrophic bacteria in Holocene sediments of an alpine meromictic lake and indicate that the water column stratification and the bacterial plume were already present in Lake Cadagno thousands of years ago. The finding of Chlorobium clathratiforme remains in all the samples analyzed shows that this population, identified in the water column only in 2001, was already a part of the lake's biota in the past.
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Affiliation(s)
- D F Ravasi
- Piora Alpine Biology Centre Foundation, c/o Cantonal Institute of Microbiology, Bellinzona, Switzerland.
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31
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Galand PE, Bourrain M, De Maistre E, Catala P, Desdevises Y, Elifantz H, Kirchman DL, Lebaron P. Phylogenetic and functional diversity of Bacteria and Archaea in a unique stratified lagoon, the Clipperton atoll (N Pacific). FEMS Microbiol Ecol 2012; 79:203-17. [PMID: 22029483 DOI: 10.1111/j.1574-6941.2011.01209.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The Clipperton lagoon in the North Pacific Ocean has been isolated from the surrounding sea for c. 160 years. It has a stratified water column that comprises an oxic and brackish upper water layer (mixolimnion) and a deep sulfuric anoxic saline layer (monimolimnion), separated by a steep pycnocline. Here, we test whether the Clipperton lagoon with its distinctive physico-chemical features, geographic isolation, recent water column stratification, and large nutrient input harbors original microbial communities. The combination of capillary electrophoresis single-strand polymorphism (CE-SSCP) fingerprinting and sequencing of cloned bacterial and archaeal 16S rRNA genes, and functional genes for methanogenesis (mcrA), methanotrophy (pmoA), and sulfate reduction (dsrAB), revealed that microbial communities and pathways were highly stratified down the water column. The mixolimnion contained ubiquitous freshwater clades of Alpha- and Betaproteobacteria, while the pycnocline contained mostly green sulfur bacteria (phylum Chlorobi). Sequences of the upper layers were closely related to sequences found in other aquatic ecosystems, suggesting that they have a strong potential for dispersal and colonization. In contrast, the monimolimnion contained new deeply branching bacterial divisions within the OP11 cluster and the Bacteroidetes, and was the most diverse of the layers. The unique environmental conditions characterizing the deep layers of the lagoon may explain the novelty of the microbial communities found at the Clipperton atoll.
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Affiliation(s)
- Pierre E Galand
- UPMC Univ Paris 06, Observatoire Océ anologique, Banyuls-sur-Mer, France.
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32
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Gregersen LH, Bryant DA, Frigaard NU. Mechanisms and evolution of oxidative sulfur metabolism in green sulfur bacteria. Front Microbiol 2011; 2:116. [PMID: 21833341 PMCID: PMC3153061 DOI: 10.3389/fmicb.2011.00116] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 05/11/2011] [Indexed: 11/13/2022] Open
Abstract
Green sulfur bacteria (GSB) constitute a closely related group of photoautotrophic and thiotrophic bacteria with limited phenotypic variation. They typically oxidize sulfide and thiosulfate to sulfate with sulfur globules as an intermediate. Based on genome sequence information from 15 strains, the distribution and phylogeny of enzymes involved in their oxidative sulfur metabolism was investigated. At least one homolog of sulfide:quinone oxidoreductase (SQR) is present in all strains. In all sulfur-oxidizing GSB strains except the earliest diverging Chloroherpeton thalassium, the sulfide oxidation product is further oxidized to sulfite by the dissimilatory sulfite reductase (DSR) system. This system consists of components horizontally acquired partly from sulfide-oxidizing and partly from sulfate-reducing bacteria. Depending on the strain, the sulfite is probably oxidized to sulfate by one of two different mechanisms that have different evolutionary origins: adenosine-5'-phosphosulfate reductase or polysulfide reductase-like complex 3. Thiosulfate utilization by the SOX system in GSB has apparently been acquired horizontally from Proteobacteria. SoxCD does not occur in GSB, and its function in sulfate formation in other bacteria has been replaced by the DSR system in GSB. Sequence analyses suggested that the conserved soxJXYZAKBW gene cluster was horizontally acquired by Chlorobium phaeovibrioides DSM 265 from the Chlorobaculum lineage and that this acquisition was mediated by a mobile genetic element. Thus, the last common ancestor of currently known GSB was probably photoautotrophic, hydrogenotrophic, and contained SQR but not DSR or SOX. In addition, the predominance of the Chlorobium-Chlorobaculum-Prosthecochloris lineage among cultured GSB could be due to the horizontally acquired DSR and SOX systems. Finally, based upon structural, biochemical, and phylogenetic analyses, a uniform nomenclature is suggested for sqr genes in prokaryotes.
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Affiliation(s)
- Lea H. Gregersen
- Department of Biology, University of CopenhagenHelsingør, Denmark
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State UniversityUniversity Park, PA, USA
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33
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Abstract
In nature, the complexity and structure of microbial communities varies widely, ranging from a few species to thousands of species, and from highly structured to highly unstructured communities. Here, we describe the identity and functional capacity of microbial populations within distinct layers of a pristine, marine-derived, meromictic (stratified) lake (Ace Lake) in Antarctica. Nine million open reading frames were analyzed, representing microbial samples taken from six depths of the lake size fractionated on sequential 3.0, 0.8 and 0.1 μm filters, and including metaproteome data from matching 0.1 μm filters. We determine how the interactions of members of this highly structured and moderately complex community define the biogeochemical fluxes throughout the entire lake. Our view is that the health of this delicate ecosystem is dictated by the effects of the polar light cycle on the dominant role of green sulfur bacteria in primary production and nutrient cycling, and the influence of viruses/phage and phage resistance on the cooperation between members of the microbial community right throughout the lake. To test our assertions, and develop a framework applicable to other microbially driven ecosystems, we developed a mathematical model that describes how cooperation within a microbial system is impacted by periodic fluctuations in environmental parameters on key populations of microorganisms. Our study reveals a mutualistic structure within the microbial community throughout the lake that has arisen as the result of mechanistic interactions between the physico-chemical parameters and the selection of individual members of the community. By exhaustively describing and modelling interactions in Ace Lake, we have developed an approach that may be applicable to learning how environmental perturbations affect the microbial dynamics in more complex aquatic systems.
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34
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Habicht KS, Miller M, Cox RP, Frigaard NU, Tonolla M, Peduzzi S, Falkenby LG, Andersen JS. Comparative proteomics and activity of a green sulfur bacterium through the water column of Lake Cadagno, Switzerland. Environ Microbiol 2010; 13:203-215. [PMID: 20731699 DOI: 10.1111/j.1462-2920.2010.02321.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primary production in the meromictic Lake Cadagno, Switzerland, is dominated by anoxygenic photosynthesis. The green sulfur bacterium Chlorobium clathratiforme is the dominant phototrophic organism in the lake, comprising more than half of the bacterial population, and its biomass increases 3.8-fold over the summer. Cells from four positions in the water column were used for comparative analysis of the Chl. clathratiforme proteome in order to investigate changes in protein composition in response to the chemical and physical gradient in their environment, with special focus on how the bacteria survive in the dark. Although metagenomic data are not available for Lake Cadagno, proteome analysis was possible based on the completely sequenced genome of an isolated strain of Chl. clathratiforme. Using LC-MS/MS we identified 1321 Chl. clathratiforme proteins in Lake Cadagno and quantitatively compared 621 of these in the four samples. Our results showed that compared with cells obtained from the photic zone, cells collected from the dark part of the water column had the same expression level of key enzymes involved in carbon metabolism and photosynthetic light harvesting. However, most proteins participating in nitrogen and sulfur metabolism were twofold less abundant in the dark. From the proteome analysis we were able to show that Chl. clathratiforme in the photic zone contains enzymes for fixation of N(2) and the complete oxidation of sulfide to sulfate while these processes are probably not active in the dark. Instead we propose that Chl. clathratiforme cells in the dark part of the water column obtain energy for maintenance from the fermentation of polyglucose. Based on the observed protein compositions we have constructed possible pathways for C, N and S metabolism in Chl. clathratiforme.
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Affiliation(s)
- Kirsten S Habicht
- Department of Biology and Nordic Center for Earth EvolutionDepartment of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.Cantonal Institute of Microbiology, CH-6500 Bellinzona and Microbial Ecology and Microbiology Unit, Plant Biology Department, University of Geneva, CH-1211 Geneva, Switzerland.Alpine Biology Center Foundation Piora, Quinto, Switzerland
| | - Mette Miller
- Department of Biology and Nordic Center for Earth EvolutionDepartment of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.Cantonal Institute of Microbiology, CH-6500 Bellinzona and Microbial Ecology and Microbiology Unit, Plant Biology Department, University of Geneva, CH-1211 Geneva, Switzerland.Alpine Biology Center Foundation Piora, Quinto, Switzerland
| | - Raymond P Cox
- Department of Biology and Nordic Center for Earth EvolutionDepartment of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.Cantonal Institute of Microbiology, CH-6500 Bellinzona and Microbial Ecology and Microbiology Unit, Plant Biology Department, University of Geneva, CH-1211 Geneva, Switzerland.Alpine Biology Center Foundation Piora, Quinto, Switzerland
| | - Niels-Ulrik Frigaard
- Department of Biology and Nordic Center for Earth EvolutionDepartment of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.Cantonal Institute of Microbiology, CH-6500 Bellinzona and Microbial Ecology and Microbiology Unit, Plant Biology Department, University of Geneva, CH-1211 Geneva, Switzerland.Alpine Biology Center Foundation Piora, Quinto, Switzerland
| | - Mauro Tonolla
- Department of Biology and Nordic Center for Earth EvolutionDepartment of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.Cantonal Institute of Microbiology, CH-6500 Bellinzona and Microbial Ecology and Microbiology Unit, Plant Biology Department, University of Geneva, CH-1211 Geneva, Switzerland.Alpine Biology Center Foundation Piora, Quinto, Switzerland
| | - Sandro Peduzzi
- Department of Biology and Nordic Center for Earth EvolutionDepartment of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.Cantonal Institute of Microbiology, CH-6500 Bellinzona and Microbial Ecology and Microbiology Unit, Plant Biology Department, University of Geneva, CH-1211 Geneva, Switzerland.Alpine Biology Center Foundation Piora, Quinto, Switzerland
| | - Lasse G Falkenby
- Department of Biology and Nordic Center for Earth EvolutionDepartment of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.Cantonal Institute of Microbiology, CH-6500 Bellinzona and Microbial Ecology and Microbiology Unit, Plant Biology Department, University of Geneva, CH-1211 Geneva, Switzerland.Alpine Biology Center Foundation Piora, Quinto, Switzerland
| | - Jens S Andersen
- Department of Biology and Nordic Center for Earth EvolutionDepartment of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.Cantonal Institute of Microbiology, CH-6500 Bellinzona and Microbial Ecology and Microbiology Unit, Plant Biology Department, University of Geneva, CH-1211 Geneva, Switzerland.Alpine Biology Center Foundation Piora, Quinto, Switzerland
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