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Béchade B, Cabuslay CS, Hu Y, Mendonca CM, Hassanpour B, Lin JY, Su Y, Fiers VJ, Anandarajan D, Lu R, Olson CJ, Duplais C, Rosen GL, Moreau CS, Aristilde L, Wertz JT, Russell JA. Physiological and evolutionary contexts of a new symbiotic species from the nitrogen-recycling gut community of turtle ants. THE ISME JOURNAL 2023; 17:1751-1764. [PMID: 37558860 PMCID: PMC10504363 DOI: 10.1038/s41396-023-01490-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/21/2023] [Accepted: 07/27/2023] [Indexed: 08/11/2023]
Abstract
While genome sequencing has expanded our knowledge of symbiosis, role assignment within multi-species microbiomes remains challenging due to genomic redundancy and the uncertainties of in vivo impacts. We address such questions, here, for a specialized nitrogen (N) recycling microbiome of turtle ants, describing a new genus and species of gut symbiont-Ischyrobacter davidsoniae (Betaproteobacteria: Burkholderiales: Alcaligenaceae)-and its in vivo physiological context. A re-analysis of amplicon sequencing data, with precisely assigned Ischyrobacter reads, revealed a seemingly ubiquitous distribution across the turtle ant genus Cephalotes, suggesting ≥50 million years since domestication. Through new genome sequencing, we also show that divergent I. davidsoniae lineages are conserved in their uricolytic and urea-generating capacities. With phylogenetically refined definitions of Ischyrobacter and separately domesticated Burkholderiales symbionts, our FISH microscopy revealed a distinct niche for I. davidsoniae, with dense populations at the anterior ileum. Being positioned at the site of host N-waste delivery, in vivo metatranscriptomics and metabolomics further implicate I. davidsoniae within a symbiont-autonomous N-recycling pathway. While encoding much of this pathway, I. davidsoniae expressed only a subset of the requisite steps in mature adult workers, including the penultimate step deriving urea from allantoate. The remaining steps were expressed by other specialized gut symbionts. Collectively, this assemblage converts inosine, made from midgut symbionts, into urea and ammonia in the hindgut. With urea supporting host amino acid budgets and cuticle synthesis, and with the ancient nature of other active N-recyclers discovered here, I. davidsoniae emerges as a central player in a conserved and impactful, multipartite symbiosis.
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Affiliation(s)
- Benoît Béchade
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA.
| | - Christian S Cabuslay
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
| | - Yi Hu
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
- State Key Laboratory of Earth Surface Processes and Resource Ecology and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Caroll M Mendonca
- Department of Civil and Environmental Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, 60208, USA
| | - Bahareh Hassanpour
- Department of Civil and Environmental Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, 60208, USA
| | - Jonathan Y Lin
- Department of Biology, Calvin University, 1726 Knollcrest Circle SE, Grand Rapids, MI, 49546-4402, USA
| | - Yangzhou Su
- Department of Biology, Calvin University, 1726 Knollcrest Circle SE, Grand Rapids, MI, 49546-4402, USA
| | - Valerie J Fiers
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
| | - Dharman Anandarajan
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
| | - Richard Lu
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
| | - Chandler J Olson
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
- Department of Biological Sciences, University of Alabama, 1325 Hackberry Ln, Tuscaloosa, AL, 35487, USA
| | - Christophe Duplais
- Department of Entomology, Cornell University, Cornell AgriTech, Geneva, NY, 14456, USA
| | - Gail L Rosen
- Ecological and Evolutionary Signal-Processing and Informatics Laboratory, Department of Electrical and Computer Engineering, Drexel University, 3141 Chestnut St., Philadelphia, PA, 19104, USA
| | - Corrie S Moreau
- Department of Entomology, Cornell University, Cornell AgriTech, Geneva, NY, 14456, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Ludmilla Aristilde
- Department of Civil and Environmental Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, 60208, USA
| | - John T Wertz
- Department of Biology, Calvin University, 1726 Knollcrest Circle SE, Grand Rapids, MI, 49546-4402, USA
| | - Jacob A Russell
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA, 19104, USA
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Sun K, Yu M, Zhu XY, Xue CX, Zhang Y, Chen X, Yao P, Chen L, Fu L, Yang Z, Zhang XH. Microbial communities related to the sulfur cycle in the Sansha Yongle Blue Hole. Microbiol Spectr 2023; 11:e0114923. [PMID: 37623326 PMCID: PMC10580873 DOI: 10.1128/spectrum.01149-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 07/13/2023] [Indexed: 08/26/2023] Open
Abstract
The Sansha Yongle Blue Hole (SYBH), the deepest blue hole in the world, is an excellent habitat for revealing biogeochemical cycles in the anaerobic environment. However, how sulfur cycling is mediated by microorganisms in the SYBH hasn't been fully understood. In this study, the water layers of the SYBH were divided into oxic zone, hypoxic zone, anoxic zone I and II, and microbial-mediated sulfur cycling in the SYBH was comprehensively interpreted. The 16S rRNA genes/transcripts analyses showed that the microbial community structures associated with the sulfur cycling in each zone had distinctive features. Sulfur-oxidizing bacteria were mostly constituted by Gammaproteobacteria, Alphaproteobacteria, Campylobacterota, and Chlorobia above the anoxic zone I and sulfate-reducing bacteria were dominated by Desulfobacterota in anoxic zones. Metagenomic analyses showed that the sulfide-oxidation-related gene sqr and genes encoding the Sox system were mainly distributed in the anoxic zone I, while genes related to dissimilatory sulfate reduction and sulfur intermediate metabolite reduction were mainly distributed in the anoxic zone II, indicating different sulfur metabolic processes between these two zones. Moreover, sulfur-metabolism-related genes were identified in 81 metagenome-assembled genomes (MAGs), indicating a high diversity of microbial communities involved in sulfur cycling. Among them, three MAGs from the candidate phyla JdFR-76 and AABM5-125-24 with genes related to dissimilatory sulfate reduction exhibited distinctive metabolic features. Our results showed unique and novel microbial populations in the SYBH sulfur cycle correlated to the sharp redox gradients, revealing complex biogeochemical processes in this extreme environment. IMPORTANCE Oxygen-deficient regions in the global ocean are expanding rapidly and affect the growth, reproduction and ecological processes of marine organisms. The anaerobic water body of about 150 m in the Sansha Yongle Blue Hole (SYBH) provided a suitable environment to study the specific microbial metabolism in anaerobic seawater. Here, we found that the vertical distributions of the total and active communities of sulfur-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB) were different in each water layer of the SYBH according to the dissolved oxygen content. Genes related to sulfur metabolism also showed distinct stratification characteristics. Furthermore, we have obtained diverse metagenome-assembled genomes, some of which exhibit special sulfur metabolic characteristics, especially candidate phyla JdFR-76 and AABM5-125-24 were identified as potential novel SRB. The results of this study will promote further understanding of the sulfur cycle in extreme environments, as well as the environmental adaptability of microorganisms in blue holes.
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Affiliation(s)
- Kai Sun
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Min Yu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiao-Yu Zhu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Chun-Xu Xue
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yunhui Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xing Chen
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Peng Yao
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China
| | - Lin Chen
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China
| | - Liang Fu
- Sansha Track Ocean Coral Reef Conservation Research Institute, Sansha, China
| | - Zuosheng Yang
- College of Marine Geosciences, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
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3
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Fan K, Wang W, Xu X, Yuan Y, Ren N, Lee DJ, Chen C. Recent Advances in Biotechnologies for the Treatment of Environmental Pollutants Based on Reactive Sulfur Species. Antioxidants (Basel) 2023; 12:antiox12030767. [PMID: 36979016 PMCID: PMC10044940 DOI: 10.3390/antiox12030767] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/19/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
The definition of reactive sulfur species (RSS) is inspired by the reactivity and variable chemical valence of sulfur. Sulfur is an essential element for life and is a part of global geochemical cycles. Wastewater treatment bioreactors can be divided into two major categories: sulfur reduction and sulfur oxidation. We review the origins of the definition of RSS and related biotechnological processes in environmental management. Sulfate reduction, sulfide oxidation, and sulfur-based redox reactions are key to driving the coupled global carbon, nitrogen, and sulfur co-cycles. This shows the coupling of the sulfur cycle with the carbon and nitrogen cycles and provides insights into the global material-chemical cycle. We also review the biological classification and RSS metabolic mechanisms of functional microorganisms involved in the biological processes, such as sulfate-reducing and sulfur-oxidizing bacteria. Developments in molecular biology and genomic technologies have allowed us to obtain detailed information on these bacteria. The importance of RSS in environmental technologies requires further consideration.
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Affiliation(s)
- Kaili Fan
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wei Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xijun Xu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yuan Yuan
- College of Biological Engineering, Beijing Polytechnic, Beijing 100176, China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Duu-Jong Lee
- Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Chuan Chen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
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Chou PH, Hu MY, Guh YJ, Wu GC, Yang SH, Tandon K, Shao YT, Lin LY, Chen C, Tseng KY, Wang MC, Zhang CM, Han BC, Lin CC, Tang SL, Jeng MS, Chang CF, Tseng YC. Cellular mechanisms underlying extraordinary sulfide tolerance in a crustacean holobiont from hydrothermal vents. Proc Biol Sci 2023; 290:20221973. [PMID: 36629118 PMCID: PMC9832567 DOI: 10.1098/rspb.2022.1973] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 11/17/2022] [Indexed: 01/12/2023] Open
Abstract
The shallow-water hydrothermal vent system of Kueishan Island has been described as one of the world's most acidic and sulfide-rich marine habitats. The only recorded metazoan species living in the direct vicinity of the vents is Xenograpsus testudinatus, a brachyuran crab endemic to marine sulfide-rich vent systems. Despite the toxicity of hydrogen sulfide, X. testudinatus occupies an ecological niche in a sulfide-rich habitat, with the underlying detoxification mechanism remaining unknown. Using laboratory and field-based experiments, we characterized the gills of X. testudinatus that are the major site of sulfide detoxification. Here sulfide is oxidized to thiosulfate or bound to hypotaurine to generate the less toxic thiotaurine. Biochemical and molecular analyses demonstrated that the accumulation of thiosulfate and hypotaurine is mediated by the sodium-independent sulfate anion transporter (SLC26A11) and taurine transporter (Taut), which are expressed in gill epithelia. Histological and metagenomic analyses of gill tissues demonstrated a distinct bacterial signature dominated by Epsilonproteobacteria. Our results suggest that thiotaurine synthesized in gills is used by sulfide-oxidizing endo-symbiotic bacteria, creating an effective sulfide-buffering system. This work identified physiological mechanisms involving host-microbe interactions that support life of a metazoan in one of the most extreme environments on our planet.
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Affiliation(s)
- Pei-Hsuan Chou
- Marine Research Station (MRS), Institute of Cellular and Organismic Biology, Academia Sinica, I-Lan County, Taiwan
| | - Marian Y. Hu
- Institute of Physiology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Ying-Jey Guh
- Marine Research Station (MRS), Institute of Cellular and Organismic Biology, Academia Sinica, I-Lan County, Taiwan
| | - Guan-Chung Wu
- Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan
- Center of Excellence for the Oceans National Taiwan Ocean University, Keelung, Taiwan
| | - Shan-Hua Yang
- Institute of Fisheries Science, National Taiwan University, Taipei City, Taiwan
| | - Kshitij Tandon
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan
| | - Yi-Ta Shao
- Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan
| | - Li-Yih Lin
- Department of Life Science, National Taiwan Normal University, Taipei City, Taiwan
| | - Chi Chen
- Doctoral Degree Program in Marine Biotechnology, National Taiwan Ocean University and Academia Sinica, Taipei City, Taiwan
| | - Kuang-Yu Tseng
- Department of Life Science, Tunghai University, Taichung, Taiwan
| | - Min-Chen Wang
- Marine Research Station (MRS), Institute of Cellular and Organismic Biology, Academia Sinica, I-Lan County, Taiwan
| | - Cheng-Mao Zhang
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan
| | - Bor-Cheng Han
- School of Public Health, Taipei Medical College, Taipei, Taiwan
| | - Ching-Chun Lin
- Biomedical Translation Research Center, Academia Sinica, Taipei City, Taiwan
| | - Sen-Lin Tang
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan
| | - Ming-Shiou Jeng
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan
| | - Ching-Fong Chang
- Center of Excellence for the Oceans National Taiwan Ocean University, Keelung, Taiwan
| | - Yung-Che Tseng
- Marine Research Station (MRS), Institute of Cellular and Organismic Biology, Academia Sinica, I-Lan County, Taiwan
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5
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Bhagat C, Kumar M. Muddy (silty-sand) beaches in semi-arid regions attenuate the contaminants flowing into the sea as a submarine groundwater discharge. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 833:155111. [PMID: 35398430 DOI: 10.1016/j.scitotenv.2022.155111] [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: 02/04/2022] [Revised: 03/20/2022] [Accepted: 04/04/2022] [Indexed: 06/14/2023]
Abstract
Urbanized coastal areas are well-recognized hotspots for the contaminant-enriched groundwater discharge, influencing sensitive coastal ecosystems. The present study investigates how muddy beaches in the semi-arid region alter the contaminant flux flowing into the sea using submarine groundwater discharge (SGD) estimation and hydrogeochemical analysis of coastal waters (groundwater, porewater, and seawater). Fresh SGD carries contaminants such as nutrients and trace metals in the coastal ecosystem, causing increased vulnerability towards eutrophication, harmful algal blooms, and human health. We found that SGD reaching the coast carries immense nutrient flux (155.6 mmol NO3- · day-1; 35 mmol P · day-1 and 12.4 mmol DSi · day-1) and trace metal load ranging from 0.1 to 14.9 mmol · day-1. The nutrient fluxes were higher in the upper saline plume compared to the lower plume. The muddy beach attenuates the nutrients in varying percentages of 9.7 to 22% of NO3-, 1.9 to 25.5% of P due to denitrification and phosphorus absorption, and also caused 19.6% reduction of SO42-. The reduction in SO42- leads to the formation of sulfide (HS-) that promotes the metal precipitation, resulting in the removal of Pb and Cu. This attenuation of nutrients leads to a change in the nutrient ratio (N/P = 7-11) approaching the Redfield ratio, implying the vulnerability of algal bloom at the Dehri beach. Overall, the muddy beach can serve as a natural biogeochemical reactor as it attenuates the nutrient and serves as a source for certain trace metals (Fe, Mn, Zn, and Ni), altering the composition of SGD. Probably this is the first study that emphasizes the attenuation of trace metals in the muddy beaches of a semi-arid region.
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Affiliation(s)
- Chandrashekhar Bhagat
- Discipline of Civil Engineering, Indian Institute of Technology Gandhinagar, Palaj Gandhinagar, Gujarat 382355, India
| | - Manish Kumar
- Sustainability Cluster, School of Engineering, University of Petroleum & Energy Studies, Dehradun, Uttarakhand 248007, India.
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Mojarro A, Cui X, Zhang X, Jost AB, Bergmann KD, Vinther J, Summons RE. Comparative soft-tissue preservation in Holocene-age capelin concretions. GEOBIOLOGY 2022; 20:377-398. [PMID: 34747129 DOI: 10.1111/gbi.12480] [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: 10/30/2020] [Revised: 10/21/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
Determining how soft tissues are preserved and persist through geologic time are continuing challenge because decay begins immediately after senescence while diagenetic transformations generally progress over days to millions of years. However, in recent years, carbonate concretions containing partially-to-fully decayed macroorganisms have proven to be remarkable windows into the diagenetic continuum revealing insights into the fossilization process. This is because most concretions are the result of biologically induced mineral precipitation caused by the localized decay of organic matter, which oftentimes preserves a greater biological signal relative to their host sediment. Here we present a comparative lipid biomarker study investigating processes associated with soft-tissue preservation within Holocene-age carbonate concretions that have encapsulated modern capelin (Mallotus villosus). We focus on samples collected from two depositional settings that have produced highly contrasting preservation end-members: (1) Kangerlussuaq, Greenland: a marine environment, which, due to isostatic rebound, has exposed strata containing concretions exhibiting exceptional soft-tissue preservation (6-7 kya), and (2) Greens Creek, Ottawa, Canada: a paleo brackish-to-freshwater marine excursion containing concretions exhibiting skeletal remains (~11 kya). Lipid biomarker analysis reveals endogenous capelin tissues and productive waters at Kangerlussuaq that are in sharp contrast to Greens Creek concretions, which lack appreciable capelin and environmental signals. Comparable distributions of bacterial fatty acids and statistical analyses suggest soft-tissue preservation within concretions is agnostic to specific heterotrophic decay communities. We, therefore, interpret preservation within carbonate concretions may represent a race between microbially induced authigenic precipitation and decay. Namely, factors resulting in exceptional preservation within concretions likely include: (1) organic matter input, (2) rate of decay, (3) carbonate saturation, (4) porewater velocity, and (5) rate of authigenic (carbonate) precipitation resulting in arrested decay/bacterial respiration due to cementing pore spaces limiting the diffusion of electron acceptors into the decay foci.
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Affiliation(s)
- Angel Mojarro
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Xingqian Cui
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Xiaowen Zhang
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Adam B Jost
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kristin D Bergmann
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Jakob Vinther
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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7
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Bremer K, Yasuo H, Debes PV, Jacobs HT. The alternative oxidase (AOX) increases sulphide tolerance in the highly invasive marine invertebrate Ciona intestinalis. J Exp Biol 2021; 224:jeb242985. [PMID: 34423818 PMCID: PMC8407659 DOI: 10.1242/jeb.242985] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/26/2021] [Indexed: 12/29/2022]
Abstract
Ecological communities and biodiversity are shaped by both abiotic and biotic factors. This is well illustrated by extreme environments and invasive species. Besides naturally occurring sulphide-rich environments, global change can lead to an increase in hydrogen sulphide episodes that threaten many multicellular organisms. With the increase in the formation, size and abundance of oxygen minimum zones and hypoxic environments, bacterial-associated sulphide production is favoured and, as such, hydrogen-sulphide-rich environments are likely to also increase in size and abundance. Many species are challenged by the inhibiting effect of sulphide on aerobic energy production via cytochrome c oxidase, ultimately causing the death of the organism. Interestingly, many protist, yeast, plant and also animal species possess a sulphide-resistant alternative oxidase (AOX). In this study, we investigated whether AOX is functionally involved in the sulphide stress response of the highly invasive marine tunicate Ciona intestinalis. At the LC50, the sulphide-induced reduction of developmental success was three times stronger in AOX knock-down embryos than in control embryos. Further, AOX mRNA levels were higher under sulphide than under control conditions, and this effect increased during embryonic development. Together, we found that AOX is indeed functionally involved in the sulphide tolerance of C. intestinalis embryos, hence, very likely contributing to its invasive potential; and that the response of AOX to sulphide seems to be controlled at the transcriptional level. We suggest that AOX-possessing species play an important role in shaping marine ecological communities, and this importance may increase under ongoing global change.
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Affiliation(s)
- Katharina Bremer
- Tampere University, Faculty of Medicine and Health Technology, 33014 Tampere, Finland
| | - Hitoyoshi Yasuo
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Paul Vincent Debes
- Hólar University College, Department of Aquaculture and Fish Biology, 551 Sauðárkrókur, Iceland
| | - Howard Trevor Jacobs
- Tampere University, Faculty of Medicine and Health Technology, 33014 Tampere, Finland
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Assessment of the Main Geochemical Processes Affecting Surface Water and Groundwater in a Low-Lying Coastal Area: Implications for Water Management. WATER 2020. [DOI: 10.3390/w12061720] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hydrogeochemical analyses were carried out to identify geochemical processes occurring in the low-lying coastal aquifer of Ravenna, North Adriatic Sea (Italy). The area is characterized by a complex coexistence of several environments: coastal dunes, paleodunes, pine forests, freshwater wetlands, rivers, brackish lagoons, gravel pit lakes, reclaimed lands, agricultural fields and industrial areas. Water quality is of primary importance for the sustainability of these, areas and a full understanding of geochemical processing is fundamental for their management. A total of 104 water samples was collected from groundwater wells and surface water bodies, and analyzed for the major and trace elements (TEs). Field measurements of chemical-physical parameters were carried out by a multiparameter device XS PCD650; major elements were analyzed following the Italian National Environmental Agency standards (APAT-IRSA 2003), while TEs were analyzed by ICP-AES/ICP-MS. The major findings include: organic matter degradation in salinized and anoxic conditions; TEs concentrations related to water–sediment interactions, i.e., adsorption, ion exchange, redox reactions, mineral dissolution and precipitation; anthropogenic contamination from pesticides and fertilizers use; pollution from industrial district; TEs enrichments and depletion due to groundwater salinization and water management practices; comparison of TEs concentrations with respect to national and international thresholds. The findings can provide water managers and local authorities with a comprehensive framework of the coastal water hydrochemistry, allowing a better understanding of the effects of current management practices and the design of mitigation measures to reduce water resource deterioration in the studied coastal area.
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9
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Lahme S, Callbeck CM, Eland LE, Wipat A, Enning D, Head IM, Hubert CR. Comparison of sulfide‐oxidizing
Sulfurimonas
strains reveals a new mode of thiosulfate formation in subsurface environments. Environ Microbiol 2020; 22:1784-1800. [DOI: 10.1111/1462-2920.14894] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/02/2019] [Accepted: 12/11/2019] [Indexed: 01/18/2023]
Affiliation(s)
- Sven Lahme
- School of Natural and Environmental SciencesNewcastle University Devonshire Building (3rd floor) Newcastle upon Tyne NE1 7RU UK
| | | | - Lucy E. Eland
- School of ComputingNewcastle University Newcastle upon Tyne UK
| | - Anil Wipat
- School of ComputingNewcastle University Newcastle upon Tyne UK
| | - Dennis Enning
- ExxonMobil Upstream Research Company Spring Texas USA
| | - Ian M. Head
- School of Natural and Environmental SciencesNewcastle University Devonshire Building (3rd floor) Newcastle upon Tyne NE1 7RU UK
| | - Casey R.J. Hubert
- School of Natural and Environmental SciencesNewcastle University Devonshire Building (3rd floor) Newcastle upon Tyne NE1 7RU UK
- Department of Biological SciencesUniversity of Calgary Calgary Canada
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10
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Sam Kamaleson A, Gonsalves MJ, Nazareth DR. Interactions of sulfur and methane-oxidizing bacteria in tropical estuarine sediments. ENVIRONMENTAL MONITORING AND ASSESSMENT 2019; 191:496. [PMID: 31312943 DOI: 10.1007/s10661-019-7616-8] [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: 12/06/2018] [Accepted: 06/24/2019] [Indexed: 06/10/2023]
Abstract
The bacterial oxidation of sulfur and methane is central to the biogeochemical processes in sediments such as the tropical mangrove sediments. However, there is a lacuna of information on the seasonal interactions including the influence of monsoons which is a major driver of seasonal change, on sulfur-oxidizing bacteria (SOB) and methane-oxidizing bacteria (MOB), their activity and the environmental variables. To understand these interactions, the analysis was carried out on sediment samples that were sampled monthly for a year from Chorao mangrove, Goa, southwest coast of India. SOB (3.8×105CFU g-1) and MOB (0.90×105CFU g-1) had maximum average abundance in the surface sediments in the post-monsoon and monsoon season, respectively. The mean sulfur-oxidation activity (SOA) of 2.63 mM day-1 and methane-oxidation activity (MOA) of 110.94 mM day-1 were highest in surface sediments during the post-monsoon season. Generally, the activity of SOB and MOB in surface sediments of post-monsoon was 2.2 times(×) and 2.8× respectively higher than that in the monsoon season. Among the environmental parameters analyzed, protein and sulfide concentrations significantly (p < 0.001) influenced SOA and MOA, respectively. There was a significant difference in SOA (p < 0.003) and MOA (p < 0.036) in surface sediments between the monsoon and the post-monsoon season. During the monsoon season, when the system is a sink of terrestrial/anthropogenic material, the interrelationship of SOB with MOA (r = 0.617, p < 0.001) and SOB with SOA (r = 0.489, p < 0.05) aids in maintaining the homeostasis of the system.
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Affiliation(s)
- A Sam Kamaleson
- CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India
- Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
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Jørgensen BB, Findlay AJ, Pellerin A. The Biogeochemical Sulfur Cycle of Marine Sediments. Front Microbiol 2019. [DOI: 10.10.3389/fmicb.2019.00849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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12
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Jørgensen BB, Findlay AJ, Pellerin A. The Biogeochemical Sulfur Cycle of Marine Sediments. Front Microbiol 2019; 10:849. [PMID: 31105660 PMCID: PMC6492693 DOI: 10.3389/fmicb.2019.00849] [Citation(s) in RCA: 210] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/02/2019] [Indexed: 11/13/2022] Open
Abstract
Microbial dissimilatory sulfate reduction to sulfide is a predominant terminal pathway of organic matter mineralization in the anoxic seabed. Chemical or microbial oxidation of the produced sulfide establishes a complex network of pathways in the sulfur cycle, leading to intermediate sulfur species and partly back to sulfate. The intermediates include elemental sulfur, polysulfides, thiosulfate, and sulfite, which are all substrates for further microbial oxidation, reduction or disproportionation. New microbiological discoveries, such as long-distance electron transfer through sulfide oxidizing cable bacteria, add to the complexity. Isotope exchange reactions play an important role for the stable isotope geochemistry and for the experimental study of sulfur transformations using radiotracers. Microbially catalyzed processes are partly reversible whereby the back-reaction affects our interpretation of radiotracer experiments and provides a mechanism for isotope fractionation. We here review the progress and current status in our understanding of the sulfur cycle in the seabed with respect to its microbial ecology, biogeochemistry, and isotope geochemistry.
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Affiliation(s)
- Bo Barker Jørgensen
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
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Buckley A, MacGregor B, Teske A. Identification, Expression and Activity of Candidate Nitrite Reductases From Orange Beggiatoaceae, Guaymas Basin. Front Microbiol 2019; 10:644. [PMID: 30984153 PMCID: PMC6449678 DOI: 10.3389/fmicb.2019.00644] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 03/14/2019] [Indexed: 11/13/2022] Open
Abstract
Orange filamentous Beggiatoaceae form massive microbial mats on hydrothermal sediments in Guaymas Basin; these bacteria are considered to oxidize sulfide with nitrate and nitrite as electron acceptors. From a previously analyzed genome of an orange Beggiatoaceae filament, three candidate genes for enzymes with nitrite-reducing function - an orange octaheme cytochrome, a nirS nitrite reductase, and a nitrite/tetrathionate-reducing octaheme cytochrome - were cloned and expressed in Escherichia coli. The expressed and purified orange cytochrome showed reduced nitrite-reducing activity compared to the multifunctional native protein obtained from microbial mats. The nirS gene product showed in vitro but no in-gel nitrite-reducing activity; and the nitrite/tetrathionate-reducing octaheme cytochrome was capable of reducing both nitrite and tetrathionate in vitro. Phylogenetic analysis shows that the orange Beggiatoaceae nirS, in contrast to the other candidate nitrite reductases, does not form monophyletic lineages with its counterparts in other large sulfur-oxidizing bacteria, and most likely represents a recent acquisition by lateral gene transfer. The nitrite/tetrathionate-reducing enzyme of the orange Beggiatoaceae is related to nitrite- and tetrathionate reductases harbored predominantly by Gammaproteobacteria, including obligate endosymbionts of hydrothermal vent tubeworms. Thus, the orange Guaymas Basin Beggiatoaceae have a repertoire of at least three different functional enzymes for nitrite reduction. By demonstrating the unusual diversity of enzymes with a potential role in nitrite reduction, we show that bacteria in highly dynamic, sulfide-rich hydrothermal vent habitats adapt to these conditions that usually prohibit nitrate and nitrite reduction. In the case of the orange Guaymas Beggiatoaceae, classical denitrification appears to be replaced by different multifunctional enzymes for nitrite and tetrathionate reduction; the resulting ecophysiological flexibility provides a new key to the dominance of these Beggiatoaceae in hydrothermal hot spots.
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Affiliation(s)
- Andrew Buckley
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Barbara MacGregor
- Department of Earth Sciences, College of Science and Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Andreas Teske
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Urbanization Altered Bacterial and Archaeal Composition in Tidal Freshwater Wetlands Near Washington DC, USA, and Buenos Aires, Argentina. Microorganisms 2019; 7:microorganisms7030072. [PMID: 30845660 PMCID: PMC6463075 DOI: 10.3390/microorganisms7030072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/14/2019] [Accepted: 03/02/2019] [Indexed: 02/03/2023] Open
Abstract
Urban expansion causes coastal wetland loss, and environmental stressors associated with development can lead to wetland degradation and loss of ecosystem services. This study investigated the effect of urbanization on prokaryotic community composition in tidal freshwater wetlands. Sites in an urban, suburban, and rural setting were located near Buenos Aires, Argentina, and Washington D.C., USA. We sampled soil associated with two pairs of functionally similar plant species, and used Illumina sequencing of the 16S rRNA gene to examine changes in prokaryotic communities. Urban stressors included raw sewage inputs, nutrient pollution, and polycyclic aromatic hydrocarbons. Prokaryotic communities changed along the gradient (nested PerMANOVA, Buenos Aires: p = 0.005; Washington D.C.: p = 0.001), but did not differ between plant species within sites. Indicator taxa included Methanobacteria in rural sites, and nitrifying bacteria in urban sites, and we observed a decrease in methanogens and an increase in ammonia-oxidizers from rural to urban sites. Functional profiles in the Buenos Aires communities showed higher abundance of pathways related to nitrification and xenobiotic degradation in the urban site. These results suggest that changes in prokaryotic taxa across the gradient were due to surrounding stressors, and communities in urban and rural wetlands are likely carrying out different functions.
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Ugarelli K, Chakrabarti S, Laas P, Stingl U. The Seagrass Holobiont and Its Microbiome. Microorganisms 2017; 5:microorganisms5040081. [PMID: 29244764 PMCID: PMC5748590 DOI: 10.3390/microorganisms5040081] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/25/2022] Open
Abstract
Seagrass meadows are ecologically and economically important components of many coastal areas worldwide. Ecosystem services provided by seagrasses include reducing the number of microbial pathogens in the water, providing food, shelter and nurseries for many species, and decreasing the impact of waves on the shorelines. A global assessment reported that 29% of the known areal extent of seagrasses has disappeared since seagrass areas were initially recorded in 1879. Several factors such as direct and indirect human activity contribute to the demise of seagrasses. One of the main reasons for seagrass die-offs all over the world is increased sulfide concentrations in the sediment that result from the activity of sulfate-reducing prokaryotes, which perform the last step of the anaerobic food chain in marine sediments and reduce sulfate to H2S. Recent seagrass die-offs, e.g., in the Florida and Biscayne Bays, were caused by an increase in pore-water sulfide concentrations in the sediment, which were the combined result of unfavorable environmental conditions and the activities of various groups of heterotrophic bacteria in the sulfate-rich water-column and sediment that are stimulated through increased nutrient concentrations. Under normal circumstances, seagrasses are able to withstand low levels of sulfide, probably partly due to microbial symbionts, which detoxify sulfide by oxidizing it to sulfur or sulfate. Novel studies are beginning to give greater insights into the interactions of microbes and seagrasses, not only in the sulfur cycle. Here, we review the literature on the basic ecology and biology of seagrasses and focus on studies describing their microbiome.
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Affiliation(s)
- Kelly Ugarelli
- Ft. Lauderdale Research and Education Center, Department of Microbiology and Cell Science, UF/IFAS, University of Florida, Davie, FL 33314, USA.
| | - Seemanti Chakrabarti
- Ft. Lauderdale Research and Education Center, Department of Microbiology and Cell Science, UF/IFAS, University of Florida, Davie, FL 33314, USA.
| | - Peeter Laas
- Ft. Lauderdale Research and Education Center, Department of Microbiology and Cell Science, UF/IFAS, University of Florida, Davie, FL 33314, USA.
| | - Ulrich Stingl
- Ft. Lauderdale Research and Education Center, Department of Microbiology and Cell Science, UF/IFAS, University of Florida, Davie, FL 33314, USA.
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Sethurajan M, Lens PNL, Horn HA, Figueiredo LHA, van Hullebusch ED. Leaching and Recovery of Metals. SUSTAINABLE HEAVY METAL REMEDIATION 2017. [DOI: 10.1007/978-3-319-61146-4_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Maheaux H, Leavitt PR, Jackson LJ. Asynchronous onset of eutrophication among shallow prairie lakes of the Northern Great Plains, Alberta, Canada. GLOBAL CHANGE BIOLOGY 2016; 22:271-283. [PMID: 26313740 DOI: 10.1111/gcb.13076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 06/04/2023]
Abstract
Coherent timing of agricultural expansion, fertilizer application, atmospheric nutrient deposition, and accelerated global warming is expected to promote synchronous fertilization of regional surface waters and coherent development of algal blooms and lake eutrophication. While broad-scale cyanobacterial expansion is evident in global meta-analyses, little is known of whether lakes in discrete catchments within a common lake district also exhibit coherent water quality degradation through anthropogenic forcing. Consequently, the primary goal of this study was to determine whether agricultural development since ca. 1900, accelerated use of fertilizer since 1960, atmospheric deposition of reactive N, or regional climate warming has resulted in coherent patterns of eutrophication of surface waters in southern Alberta, Canada. Unexpectedly, analysis of sedimentary pigments as an index of changes in total algal abundance since ca. 1850 revealed that while total algal abundance (as β-carotene, pheophytin a) increased in nine of 10 lakes over 150 years, the onset of eutrophication varied by a century and was asynchronous across basins. Similarly, analysis of temporal sequences with least-squares regression revealed that the relative abundance of cyanobacteria (echinenone) either decreased or did not change significantly in eight of the lakes since ca. 1850, whereas purple sulfur bacteria (as okenone) increased significantly in seven study sites. These patterns are consistent with the catchment filter hypothesis, which posits that lakes exhibit unique responses to common forcing associated with the influx of mass as water, nutrients, or particles.
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Affiliation(s)
- Heather Maheaux
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Peter R Leavitt
- Limnology Laboratory, Department of Biology, University of Regina, Regina, SK, S4S 0A2, Canada
| | - Leland J Jackson
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
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Cable bacteria generate a firewall against euxinia in seasonally hypoxic basins. Proc Natl Acad Sci U S A 2015; 112:13278-83. [PMID: 26446670 DOI: 10.1073/pnas.1510152112] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Seasonal oxygen depletion (hypoxia) in coastal bottom waters can lead to the release and persistence of free sulfide (euxinia), which is highly detrimental to marine life. Although coastal hypoxia is relatively common, reports of euxinia are less frequent, which suggests that certain environmental controls can delay the onset of euxinia. However, these controls and their prevalence are poorly understood. Here we present field observations from a seasonally hypoxic marine basin (Grevelingen, The Netherlands), which suggest that the activity of cable bacteria, a recently discovered group of sulfur-oxidizing microorganisms inducing long-distance electron transport, can delay the onset of euxinia in coastal waters. Our results reveal a remarkable seasonal succession of sulfur cycling pathways, which was observed over multiple years. Cable bacteria dominate the sediment geochemistry in winter, whereas, after the summer hypoxia, Beggiatoaceae mats colonize the sediment. The specific electrogenic metabolism of cable bacteria generates a large buffer of sedimentary iron oxides before the onset of summer hypoxia, which captures free sulfide in the surface sediment, thus likely preventing the development of bottom water euxinia. As cable bacteria are present in many seasonally hypoxic systems, this euxinia-preventing firewall mechanism could be widely active, and may explain why euxinia is relatively infrequently observed in the coastal ocean.
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Abstract
Environmental bacteria play a central role in the Earth's elemental cycles and represent a mostly untapped reservoir for novel metabolic capacities and biocatalysts. Over the last 15 years, the author's laboratory has focused on three major switches in the breakdown of organic carbon defined by the abundance and recalcitrance of the substrates: carbohydrates and amino acids by aerobic heterotrophs, fermentation end products by sulphate reducers and anaerobic degradation of aromatic compounds and hydrocarbons by denitrifiers and sulphate reducers. As these bacteria are novel isolates mostly not accessibly by molecular genetics, genomics combined with differential proteomics was early on applied to obtain molecular-functional insights into degradation pathways, catabolic and regulatory networks, as well as mechanisms and strategies for adapting to changing environmental conditions. This review provides some background on research motivations and briefly summarizes insights into studied model organisms, e.g. "Aromatoleum aromaticum" EbN1, Desulfobacula toluolica Tol2 and Phaeobacter inhibens DSM 17395.
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Affiliation(s)
- R Rabus
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), University Oldenburg , Oldenburg , Germany
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20
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Purcell AM, Mikucki JA, Achberger AM, Alekhina IA, Barbante C, Christner BC, Ghosh D, Michaud AB, Mitchell AC, Priscu JC, Scherer R, Skidmore ML, Vick-Majors TJ, the WISSARD Science Team. Microbial sulfur transformations in sediments from Subglacial Lake Whillans. Front Microbiol 2014; 5:594. [PMID: 25477865 PMCID: PMC4237127 DOI: 10.3389/fmicb.2014.00594] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/21/2014] [Indexed: 11/13/2022] Open
Abstract
Diverse microbial assemblages inhabit subglacial aquatic environments. While few of these environments have been sampled, data reveal that subglacial organisms gain energy for growth from reduced minerals containing nitrogen, iron, and sulfur. Here we investigate the role of microbially mediated sulfur transformations in sediments from Subglacial Lake Whillans (SLW), Antarctica, by examining key genes involved in dissimilatory sulfur oxidation and reduction. The presence of sulfur transformation genes throughout the top 34 cm of SLW sediments changes with depth. SLW surficial sediments were dominated by genes related to known sulfur-oxidizing chemoautotrophs. Sequences encoding the adenosine-5'-phosphosulfate (APS) reductase gene, involved in both dissimilatory sulfate reduction and sulfur oxidation, were present in all samples and clustered into 16 distinct operational taxonomic units. The majority of APS reductase sequences (74%) clustered with known sulfur oxidizers including those within the "Sideroxydans" and Thiobacillus genera. Reverse-acting dissimilatory sulfite reductase (rDSR) and 16S rRNA gene sequences further support dominance of "Sideroxydans" and Thiobacillus phylotypes in the top 2 cm of SLW sediments. The SLW microbial community has the genetic potential for sulfate reduction which is supported by experimentally measured low rates (1.4 pmol cm(-3)d(-1)) of biologically mediated sulfate reduction and the presence of APS reductase and DSR gene sequences related to Desulfobacteraceae and Desulfotomaculum. Our results also infer the presence of sulfur oxidation, which can be a significant energetic pathway for chemosynthetic biosynthesis in SLW sediments. The water in SLW ultimately flows into the Ross Sea where intermediates from subglacial sulfur transformations can influence the flux of solutes to the Southern Ocean.
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Affiliation(s)
- Alicia M. Purcell
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Jill A. Mikucki
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Amanda M. Achberger
- Department of Biological Sciences, Louisiana State UniversityBaton Rouge, LA, USA
| | - Irina A. Alekhina
- Climate and Environmental Research Laboratory, Arctic and Antarctic Research Institute, St.Petersburg, Russia
| | - Carlo Barbante
- Institute for the Dynamics of Environmental Processes – Consiglio Nazionale delle Ricerche and Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of VeniceVenice, Italy
| | - Brent C. Christner
- Department of Biological Sciences, Louisiana State UniversityBaton Rouge, LA, USA
| | - Dhritiman Ghosh
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Alexander B. Michaud
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | | | - John C. Priscu
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | - Reed Scherer
- Department of Geological and Environmental Sciences, Northern Illinois UniversityDeKalb, IL, USA
| | - Mark L. Skidmore
- Department of Earth Sciences, Montana State UniversityBozeman, MT, USA
| | - Trista J. Vick-Majors
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
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Effects of ecological engineered oxygenation on the bacterial community structure in an anoxic fjord in western Sweden. ISME JOURNAL 2014; 9:656-69. [PMID: 25238400 DOI: 10.1038/ismej.2014.172] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 08/05/2014] [Accepted: 08/15/2014] [Indexed: 11/09/2022]
Abstract
Oxygen-depleted bodies of water are becoming increasingly common in marine ecosystems. Solutions to reverse this trend are needed and under development, for example, by the Baltic deep-water OXygenation (BOX) project. In the framework of this project, the Swedish Byfjord was chosen for a pilot study, investigating the effects of an engineered oxygenation on long-term anoxic bottom waters. The strong stratification of the water column of the Byfjord was broken up by pumping surface water into the deeper layers, triggering several inflows of oxygen-rich water and increasing oxygen levels in the lower water column and the benthic zone up to 110 μmol l(-1).We used molecular ecologic methods to study changes in bacterial community structure in response to the oxygenation in the Byfjord. Water column samples from before, during and after the oxygenation as well as from two nearby control fjords were analyzed. Our results showed a strong shift in bacterial community composition when the bottom water in the Byfjord became oxic. Initially dominant indicator species for oxygen minimum zones such as members of the SUP05 clade declined in abundance during the oxygenation event and nearly vanished after the oxygenation was accomplished. In contrast, aerobic species like SAR11 that initially were restricted to surface waters could later be detected deep into the water column. Overall, the bacterial community in the formerly anoxic bottom waters changed to a community structure similar to those found in oxic waters, showing that an engineered oxygenation of a large body of anoxic marine water is possible and emulates that of a natural oxygenation event.
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Nielsen LP, Risgaard-Petersen N. Rethinking sediment biogeochemistry after the discovery of electric currents. ANNUAL REVIEW OF MARINE SCIENCE 2014; 7:425-442. [PMID: 25251266 DOI: 10.1146/annurev-marine-010814-015708] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The discovery of electric currents in marine sediments arose from a simple observation that conventional biogeochemistry could not explain: Sulfide oxidation in one place is closely coupled to oxygen reduction in another place, centimeters away. After experiments demonstrated that this resulted from electric coupling, the conductors were found to be long, multicellular, filamentous bacteria, now known as cable bacteria. The spatial separation of oxidation and reduction processes by these bacteria represents a shortcut in the conventional cascade of redox processes and may drive most of the oxygen consumption. In addition, it implies a separation of strong proton generators and consumers and the formation of measurable electric fields, which have several effects on mineral development and ion migration. This article reviews the work on electric currents and cable bacteria published through April 2014, with an emphasis on general trends, thought-provoking consequences, and new questions to address.
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Affiliation(s)
- Lars Peter Nielsen
- Section for Microbiology and Center for Geomicrobiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark; ,
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Patterns of Macroinvertebrate and Fish Diversity in Freshwater Sulphide Springs. DIVERSITY-BASEL 2014. [DOI: 10.3390/d6030597] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Extreme environments are characterised by the presence of physicochemical stressors and provide unique study systems to address problems in evolutionary ecology research. Sulphide springs provide an example of extreme freshwater environments; because hydrogen sulphide’s adverse physiological effects induce mortality in metazoans even at micromolar concentrations. Sulphide springs occur worldwide, but while microbial communities in sulphide springs have received broad attention, little is known about macroinvertebrates and fish inhabiting these toxic environments. We reviewed qualitative occurrence records of sulphide spring faunas on a global scale and present a quantitative case study comparing diversity patterns in sulphidic and adjacent non-sulphidic habitats across replicated river drainages in Southern Mexico. While detailed studies in most regions of the world remain scarce, available data suggests that sulphide spring faunas are characterised by low species richness. Dipterans (among macroinvertebrates) and cyprinodontiforms (among fishes) appear to dominate the communities in these habitats. At least in fish, there is evidence for the presence of highly endemic species and populations exclusively inhabiting sulphide springs. We provide a detailed discussion of traits that might predispose certain taxonomic groups to colonize sulphide springs, how colonizers subsequently adapt to cope with sulphide toxicity, and how adaptation may be linked to speciation processes.
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Morais-Silva FO, Rezende AM, Pimentel C, Santos CI, Clemente C, Varela-Raposo A, Resende DM, da Silva SM, de Oliveira LM, Matos M, Costa DA, Flores O, Ruiz JC, Rodrigues-Pousada C. Genome sequence of the model sulfate reducer Desulfovibrio gigas: a comparative analysis within the Desulfovibrio genus. Microbiologyopen 2014; 3:513-30. [PMID: 25055974 PMCID: PMC4287179 DOI: 10.1002/mbo3.184] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 04/30/2014] [Accepted: 05/15/2014] [Indexed: 11/20/2022] Open
Abstract
Desulfovibrio gigas is a model organism of sulfate-reducing bacteria of which energy metabolism and stress response have been extensively studied. The complete genomic context of this organism was however, not yet available. The sequencing of the D. gigas genome provides insights into the integrated network of energy conserving complexes and structures present in this bacterium. Comparison with genomes of other Desulfovibrio spp. reveals the presence of two different CRISPR/Cas systems in D. gigas. Phylogenetic analysis using conserved protein sequences (encoded by rpoB and gyrB) indicates two main groups of Desulfovibrio spp, being D. gigas more closely related to D. vulgaris and D. desulfuricans strains. Gene duplications were found such as those encoding fumarate reductase, formate dehydrogenase, and superoxide dismutase. Complexes not yet described within Desulfovibrio genus were identified: Mnh complex, a v-type ATP-synthase as well as genes encoding the MinCDE system that could be responsible for the larger size of D. gigas when compared to other members of the genus. A low number of hydrogenases and the absence of the codh/acs and pfl genes, both present in D. vulgaris strains, indicate that intermediate cycling mechanisms may contribute substantially less to the energy gain in D. gigas compared to other Desulfovibrio spp. This might be compensated by the presence of other unique genomic arrangements of complexes such as the Rnf and the Hdr/Flox, or by the presence of NAD(P)H related complexes, like the Nuo, NfnAB or Mnh.
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Affiliation(s)
- Fabio O Morais-Silva
- Instituto de Tecnologia Quómica e Biológica - Antonio Xavier, Universidade Nova de Lisboa (ITQB-UNL), Av. da República - Estação Agronómica Nacional, 2780-157, Oeiras, Portugal
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Fernández AB, Vera-Gargallo B, Sánchez-Porro C, Ghai R, Papke RT, Rodriguez-Valera F, Ventosa A. Comparison of prokaryotic community structure from Mediterranean and Atlantic saltern concentrator ponds by a metagenomic approach. Front Microbiol 2014; 5:196. [PMID: 24847316 PMCID: PMC4021199 DOI: 10.3389/fmicb.2014.00196] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 04/12/2014] [Indexed: 12/02/2022] Open
Abstract
We analyzed the prokaryotic community structure of a saltern pond with 21% total salts located in Isla Cristina, Huelva, Southwest Spain, close to the Atlantic ocean coast. For this purpose, we constructed a metagenome (designated as IC21) obtained by pyrosequencing consisting of 486 Mb with an average read length of 397 bp and compared it with other metagenomic datasets obtained from ponds with 19, 33, and 37% total salts acquired from Santa Pola marine saltern, located in Alicante, East Spain, on the Mediterranean coast. Although the salinity in IC21 is closer to the pond with 19% total salts from Santa Pola saltern (designated as SS19), IC21 is more similar at higher taxonomic levels to the pond with 33% total salts from Santa Pola saltern (designated as SS33), since both are predominated by the phylum Euryarchaeota. However, there are significant differences at lower taxonomic levels where most sequences were related to the genus Halorubrum in IC21 and to Haloquadratum in SS33. Within the Bacteroidetes, the genus Psychroflexus is the most abundant in IC21 while Salinibacter dominates in SS33. Sequences related to bacteriorhodopsins and halorhodopsins correlate with the abundance of Haloquadratum in Santa Pola SS19 to SS33 and of Halorubrum in Isla Cristina IC21 dataset, respectively. Differences in composition might be attributed to local ecological conditions since IC21 showed a decrease in the number of sequences related to the synthesis of compatible solutes and in the utilization of phosphonate.
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Affiliation(s)
- Ana B Fernández
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla Sevilla, Spain
| | - Blanca Vera-Gargallo
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla Sevilla, Spain
| | - Cristina Sánchez-Porro
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla Sevilla, Spain
| | - Rohit Ghai
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante Alicante, Spain
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Francisco Rodriguez-Valera
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante Alicante, Spain
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla Sevilla, Spain
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Sánchez-Andrea I, Stams AJM, Amils R, Sanz JL. Enrichment and isolation of acidophilic sulfate-reducing bacteria from Tinto River sediments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:672-8. [PMID: 24115617 DOI: 10.1111/1758-2229.12066] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 04/10/2013] [Indexed: 05/27/2023]
Abstract
Although some acidophilic and alkaliphilic species have been described recently, most of the known sulfate-reducing bacteria (SRB) grow optimally at neutral pH. In this study, sulfate reduction was studied with sediment samples from the extremely acidic Tinto River basin. Stable enrichments of SRB were obtained at pH 4 with glycerol, methanol and hydrogen; at pH 4.5 with lactate and at pH 5.5 with succinate as substrates. Inhibition of sulfate reduction by organic acids below their pKa was observed. Cloning and sequencing of 16S rRNA gene showed that fermentative bacteria (Paludibacter spp., Oscillibacter spp.) and SRB (Thermodesulfobium spp., Desulfosporosinus spp., Desulfitobacterium spp., Desulfotomaculum spp.) were co-enriched. By repeated serial dilutions and streaking on agar plates, four strains of SRB belonging to the Firmicutes phylum were obtained. Two of them show 96% 16S rRNA gene sequence similarity with Desulfosporosinus acidophilus, and a third one with Desulfosporosinus orientis. Another isolate has just 93% rRNA gene sequence similarity with the Desulfosporosinus/Desulfitobacterium cluster and might represent a novel species within a novel genus. One of the Desulfosporosinus strains was further investigated showing maximum growth at pH 5.5, and a pH-dependent inhibitory effect of organic acids and sulfide.
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Affiliation(s)
- Irene Sánchez-Andrea
- Universidad Autónoma de Madrid, Departamento de Biología Molecular, 28049, Madrid, Spain; Laboratory for Microbiology, Wageningen University, Dreijenplein 10, 6703 HB, Wageningen, The Netherlands
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Schunck H, Lavik G, Desai DK, Großkopf T, Kalvelage T, Löscher CR, Paulmier A, Contreras S, Siegel H, Holtappels M, Rosenstiel P, Schilhabel MB, Graco M, Schmitz RA, Kuypers MMM, LaRoche J. Giant hydrogen sulfide plume in the oxygen minimum zone off Peru supports chemolithoautotrophy. PLoS One 2013; 8:e68661. [PMID: 23990875 PMCID: PMC3749208 DOI: 10.1371/journal.pone.0068661] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 06/01/2013] [Indexed: 11/30/2022] Open
Abstract
In Eastern Boundary Upwelling Systems nutrient-rich waters are transported to the ocean surface, fuelling high photoautotrophic primary production. Subsequent heterotrophic decomposition of the produced biomass increases the oxygen-depletion at intermediate water depths, which can result in the formation of oxygen minimum zones (OMZ). OMZs can sporadically accumulate hydrogen sulfide (H2S), which is toxic to most multicellular organisms and has been implicated in massive fish kills. During a cruise to the OMZ off Peru in January 2009 we found a sulfidic plume in continental shelf waters, covering an area >5500 km2, which contained ∼2.2×104 tons of H2S. This was the first time that H2S was measured in the Peruvian OMZ and with ∼440 km3 the largest plume ever reported for oceanic waters. We assessed the phylogenetic and functional diversity of the inhabiting microbial community by high-throughput sequencing of DNA and RNA, while its metabolic activity was determined with rate measurements of carbon fixation and nitrogen transformation processes. The waters were dominated by several distinct γ-, δ- and ε-proteobacterial taxa associated with either sulfur oxidation or sulfate reduction. Our results suggest that these chemolithoautotrophic bacteria utilized several oxidants (oxygen, nitrate, nitrite, nitric oxide and nitrous oxide) to detoxify the sulfidic waters well below the oxic surface. The chemolithoautotrophic activity at our sampling site led to high rates of dark carbon fixation. Assuming that these chemolithoautotrophic rates were maintained throughout the sulfidic waters, they could be representing as much as ∼30% of the photoautotrophic carbon fixation. Postulated changes such as eutrophication and global warming, which lead to an expansion and intensification of OMZs, might also increase the frequency of sulfidic waters. We suggest that the chemolithoautotrophically fixed carbon may be involved in a negative feedback loop that could fuel further sulfate reduction and potentially stabilize the sulfidic OMZ waters.
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Affiliation(s)
- Harald Schunck
- Research Division Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Institute for General Microbiology, Christian-Albrechts-University, Kiel, Germany
| | - Gaute Lavik
- Department of Biogeochemistry, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Dhwani K. Desai
- Research Division Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Tobias Großkopf
- Research Division Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
| | - Tim Kalvelage
- Department of Biogeochemistry, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Carolin R. Löscher
- Institute for General Microbiology, Christian-Albrechts-University, Kiel, Germany
| | - Aurélien Paulmier
- Department of Biogeochemistry, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
- Laboratory for Studies in Geophysics and Spatial Oceanography, Institute of Research for Development, Toulouse, France
- Dirección de Investigaciones Oceanográficas, Instituto del Mar del Perú, Callao, Peru
| | - Sergio Contreras
- Department of Biogeochemistry, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
- Large Lakes Observatory, University of Minnesota Duluth, Duluth, Minnesota, United States of America
| | - Herbert Siegel
- Physical Oceanography and Instrumentation, Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany
| | - Moritz Holtappels
- Department of Biogeochemistry, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Philip Rosenstiel
- Institute of Clinical Molecular Biology, Christian-Albrechts-University, Kiel, Germany
| | - Markus B. Schilhabel
- Institute of Clinical Molecular Biology, Christian-Albrechts-University, Kiel, Germany
| | - Michelle Graco
- Dirección de Investigaciones Oceanográficas, Instituto del Mar del Perú, Callao, Peru
| | - Ruth A. Schmitz
- Institute for General Microbiology, Christian-Albrechts-University, Kiel, Germany
| | - Marcel M. M. Kuypers
- Department of Biogeochemistry, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Julie LaRoche
- Research Division Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- * E-mail:
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Pradel N, Ji B, Gimenez G, Talla E, Lenoble P, Garel M, Tamburini C, Fourquet P, Lebrun R, Bertin P, Denis Y, Pophillat M, Barbe V, Ollivier B, Dolla A. The first genomic and proteomic characterization of a deep-sea sulfate reducer: insights into the piezophilic lifestyle of Desulfovibrio piezophilus. PLoS One 2013; 8:e55130. [PMID: 23383081 PMCID: PMC3559428 DOI: 10.1371/journal.pone.0055130] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 12/18/2012] [Indexed: 01/19/2023] Open
Abstract
Desulfovibrio piezophilus strain C1TLV30(T) is a piezophilic anaerobe that was isolated from wood falls in the Mediterranean deep-sea. D. piezophilus represents a unique model for studying the adaptation of sulfate-reducing bacteria to hydrostatic pressure. Here, we report the 3.6 Mbp genome sequence of this piezophilic bacterium. An analysis of the genome revealed the presence of seven genomic islands as well as gene clusters that are most likely linked to life at a high hydrostatic pressure. Comparative genomics and differential proteomics identified the transport of solutes and amino acids as well as amino acid metabolism as major cellular processes for the adaptation of this bacterium to hydrostatic pressure. In addition, the proteome profiles showed that the abundance of key enzymes that are involved in sulfate reduction was dependent on hydrostatic pressure. A comparative analysis of orthologs from the non-piezophilic marine bacterium D. salexigens and D. piezophilus identified aspartic acid, glutamic acid, lysine, asparagine, serine and tyrosine as the amino acids preferentially replaced by arginine, histidine, alanine and threonine in the piezophilic strain. This work reveals the adaptation strategies developed by a sulfate reducer to a deep-sea lifestyle.
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Affiliation(s)
- Nathalie Pradel
- Aix-Marseille Université, Université du Sud Toulon-Var, CNRS/INSU, IRD, MIO, UM110, Marseille, France
- * E-mail: (NP); (AD)
| | - Boyang Ji
- Aix-Marseille Université, CNRS, LCB, UMR 7283, Marseille, France
| | | | - Emmanuel Talla
- Aix-Marseille Université, CNRS, LCB, UMR 7283, Marseille, France
| | - Patricia Lenoble
- Laboratoire de Finition C.E.A., Institut de Génomique – Genoscope, Evry, France
| | - Marc Garel
- Aix-Marseille Université, Université du Sud Toulon-Var, CNRS/INSU, IRD, MIO, UM110, Marseille, France
| | - Christian Tamburini
- Aix-Marseille Université, Université du Sud Toulon-Var, CNRS/INSU, IRD, MIO, UM110, Marseille, France
| | | | - Régine Lebrun
- Plate-formes Protéomique et Transcriptomique FR3479, IBiSA Marseille-Protéomique. IMM - CNRS, Marseille, France
| | - Philippe Bertin
- UMR 7156, CNRS, Université Louis Pasteur, Strasbourg, France
| | - Yann Denis
- Plate-formes Protéomique et Transcriptomique FR3479, IBiSA Marseille-Protéomique. IMM - CNRS, Marseille, France
| | | | - Valérie Barbe
- Laboratoire de Finition C.E.A., Institut de Génomique – Genoscope, Evry, France
| | - Bernard Ollivier
- Aix-Marseille Université, Université du Sud Toulon-Var, CNRS/INSU, IRD, MIO, UM110, Marseille, France
| | - Alain Dolla
- Aix-Marseille Université, CNRS, LCB, UMR 7283, Marseille, France
- * E-mail: (NP); (AD)
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Abstract
We determined a significant fraction of the genome sequence of a representative of Thiovulum, the uncultivated genus of colorless sulfur Epsilonproteobacteria, by analyzing the genome sequences of four individual cells collected from phototrophic mats from Elkhorn Slough, California. These cells were isolated utilizing a microfluidic laser-tweezing system, and their genomes were amplified by multiple-displacement amplification prior to sequencing. Thiovulum is a gradient bacterium found at oxic-anoxic marine interfaces and noted for its distinctive morphology and rapid swimming motility. The genomic sequences of the four individual cells were assembled into a composite genome consisting of 221 contigs covering 2.083 Mb including 2,162 genes. This single-cell genome represents a genomic view of the physiological capabilities of isolated Thiovulum cells. Thiovulum is the second-fastest bacterium ever observed, swimming at 615 μm/s, and this genome shows that this rapid swimming motility is a result of a standard flagellar machinery that has been extensively characterized in other bacteria. This suggests that standard flagella are capable of propelling bacterial cells at speeds much faster than typically thought. Analysis of the genome suggests that naturally occurring Thiovulum populations are more diverse than previously recognized and that studies performed in the past probably address a wide range of unrecognized genotypic and phenotypic diversities of Thiovulum. The genome presented in this article provides a basis for future isolation-independent studies of Thiovulum, where single-cell and metagenomic tools can be used to differentiate between different Thiovulum genotypes.
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Abstract
Dissolved oxygen concentration is a crucial organizing principle in marine ecosystems. As oxygen levels decline, energy is increasingly diverted away from higher trophic levels into microbial metabolism, leading to loss of fixed nitrogen and to production of greenhouse gases, including nitrous oxide and methane. In this Review, we describe current efforts to explore the fundamental factors that control the ecological and microbial biodiversity in oxygen-starved regions of the ocean, termed oxygen minimum zones. We also discuss how recent advances in microbial ecology have provided information about the potential interactions in distributed co-occurrence and metabolic networks in oxygen minimum zones, and we provide new insights into coupled biogeochemical processes in the ocean.
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Miller AW, Richardson LL. Fine structure analysis of black band disease (BBD) infected coral and coral exposed to the BBD toxins microcystin and sulfide. J Invertebr Pathol 2012; 109:27-33. [DOI: 10.1016/j.jip.2011.09.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 09/13/2011] [Indexed: 10/17/2022]
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Wassmann P. Sedimentation of particulate material in two shallow, land-locked fjords in western Norway. ACTA ACUST UNITED AC 2011. [DOI: 10.1080/00364827.1985.10419686] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Wassmann P, Aadnesen A. Hydrography, nutrients, suspended organic matter, and primary production in a shallow fjord system on the west coast of Norway. ACTA ACUST UNITED AC 2011. [DOI: 10.1080/00364827.1984.10420600] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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34
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Miller AW, Blackwelder P, Al-Sayegh H, Richardson LL. Fine-structural analysis of black band disease-infected coral reveals boring cyanobacteria and novel bacteria. DISEASES OF AQUATIC ORGANISMS 2011; 93:179-190. [PMID: 21516970 DOI: 10.3354/dao02305] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Examination of coral fragments infected with black band disease (BBD) at the fine- and ultrastructural levels using scanning (SEM) and transmission electron microscopy (TEM) revealed novel features of the disease. SEM images of the skeleton from the host coral investigated (Montastraea annularis species complex) revealed extensive boring underneath the BBD mat, with cyanobacterial filaments present within some of the bore holes. Cyanobacteria were observed to penetrate into the overlying coral tissue from within the skeleton and were present throughout the mesoglea between tissue layers (coral epidermis and gastrodermis). A population of novel, as yet unidentified, small filamentous bacteria was found at the leading edge of the migrating band. This population increased in number within the band and was present within degrading coral epithelium, suggesting a role in disease etiology. In coral tissue in front of the leading edge of the band, cyanobacterial filaments were observed to be emerging from bundles of sloughed-off epidermal tissue. Degraded gastrodermis that contained actively dividing zooxanthellae was observed using both TEM and SEM. The BBD mat contained cyanobacterial filaments that were twisted, characteristic of negative-tactic responses. Some evidence of boring was found in apparently healthy control coral fragments; however, unlike in BBD-infected fragments, there were no associated cyanobacteria. These results suggest the coral skeleton as a possible source of pathogenic BBD cyanobacteria. Additionally, SEM revealed the presence of a potentially important group of small, filamentous BBD-associated bacteria yet to be identified.
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Affiliation(s)
- Aaron W Miller
- Department of Biological Sciences, Florida International University, Miami, Florida 33199, USA.
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35
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Metagenomic assessment of a sulfur-oxidizing enrichment culture derived from marine sediment. J Microbiol 2011; 48:739-47. [DOI: 10.1007/s12275-010-0257-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 08/18/2010] [Indexed: 11/25/2022]
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36
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Brissac T, Merçot H, Gros O. Lucinidae/sulfur-oxidizing bacteria: ancestral heritage or opportunistic association? Further insights from the Bohol Sea (the Philippines). FEMS Microbiol Ecol 2010; 75:63-76. [DOI: 10.1111/j.1574-6941.2010.00989.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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37
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Van Frausum J, Middelburg JJ, Soetaert K, Meysman FJ. Different proxies for the reactivity of aquatic sediments towards oxygen: A model assessment. Ecol Modell 2010. [DOI: 10.1016/j.ecolmodel.2010.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Gray ND, Pickup RW, Jones JG, Head IM. Ecophysiological Evidence that Achromatium oxaliferum Is Responsible for the Oxidation of Reduced Sulfur Species to Sulfate in a Freshwater Sediment. Appl Environ Microbiol 2010; 63:1905-10. [PMID: 16535604 PMCID: PMC1389159 DOI: 10.1128/aem.63.5.1905-1910.1997] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Achromatium oxaliferum is a large, morphologically conspicuous, sediment-dwelling bacterium. The organism has yet to be cultured in the laboratory, and very little is known about its physiology. The presence of intracellular inclusions of calcite and sulfur have given rise to speculation that the bacterium is involved in the carbon and sulfur cycles in the sediments where it is found. Depth profiles of oxygen concentration and A. oxaliferum cell numbers in a freshwater sediment revealed that the A. oxaliferum population spanned the oxic-anoxic boundary in the top 3 to 4 cm of sediments. Some of the A. oxaliferum cells resided at depths where no oxygen was detectable, suggesting that these cells may be capable of anaerobic metabolism. The distributions of solid-phase and dissolved inorganic sulfur species in the sediment revealed that A. oxaliferum was most abundant where sulfur cycling was most intense. The sediment was characterized by low concentrations of free sulfide. However, a comparison of sulfate reduction rates in sediment cores incubated with either oxic or anoxic overlying water indicated that the oxidative and reductive components of the sulfur cycle were tightly coupled in the A. oxaliferum-bearing sediment. A positive correlation between pore water sulfate concentration and A. oxaliferum numbers was observed in field data collected over an 18-month period, suggesting a possible link between A. oxaliferum numbers and the oxidation of reduced sulfur species to sulfate. The field data were supported by laboratory incubation experiments in which sodium molybdate-treated sediment cores were augmented with highly purified suspensions of A. oxaliferum cells. Under oxic conditions, rates of sulfate production in the presence of sodium molybdate were found to correlate strongly with the number of cells added to sediment cores, providing further evidence for a role for A. oxaliferum in the oxidation of reduced sulfur.
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Marshall T, Dorman D, Gardner D, Adeshina F. Provisional Advisory Levels (PALs) for hydrogen sulfide (H2S). Inhal Toxicol 2009; 21 Suppl 3:56-72. [DOI: 10.3109/08958370903202812] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Mohan SB, Schmid M, Jetten M, Cole J. Detection and widespread distribution of the nrfA gene encoding nitrite reduction to ammonia, a short circuit in the biological nitrogen cycle that competes with denitrification. FEMS Microbiol Ecol 2009; 49:433-43. [PMID: 19712292 DOI: 10.1016/j.femsec.2004.04.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Degenerate primers to detect nrfA were designed by aligning six nrfA sequences including Escherichia coli K-12, Sulfurospirillum deleyianum and Wolinella succinogenes. These primers amplified a 490 bp fragment of nrfA. The ability of these primers to detect nrfA was tested with chromosomal DNA isolated from a variety of bacteria: they could distinguish between bacteria in which the gene is known to be present or absent. The positive reference organisms spanned the various classes of Proteobacteria, suggesting that these primers are probably generic. The primer pair F1 and R1 was also used successfully to analyse nrfA diversity from community DNA isolated from a sulphate reducing bioreactor, and from two established Anammox reactors (for an aerobic ammonia oxidation, in which nitrite is reduced by ammonia to dinitrogen gas). The nrfA clones isolated from these three sources grouped with the Bacteroidetes phylum. The nrfA primers also amplified 570 bp fragments from the Anammox community DNA. These fragments encoded a protein with four haem-binding motifs typical of a c-type cytochrome, but were unrelated to the NrfA nitrite reductase. A BLAST search failed to reveal similarity to any known proteins. However, similarity was found to one sequence, which was annotated as rapC (response regulator aspartate phosphatase), in the genome of the planctomycete Rhodopirellula baltica. These sequences possibly belong to a new class of c-type cytochrome that might be specific to members of the order Planctomycetales. The data are consistent with the proposal that cytochrome c nitrite reductases, present in the periplasm of Gram-negative bacteria, are widely distributed in many different environments where they provide a short circuit in the biological nitrogen cycle by reducing nitrite directly to ammonia.
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Affiliation(s)
- Sudesh B Mohan
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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41
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Pham VH, Yong JJ, Park SJ, Yoon DN, Chung WH, Rhee SK. Molecular analysis of the diversity of the sulfide : quinone reductase (sqr) gene in sediment environments. MICROBIOLOGY-SGM 2008; 154:3112-3121. [PMID: 18832317 DOI: 10.1099/mic.0.2008/018580-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Our newly designed primers were evaluated for the molecular analysis of specific groups of the sqr gene encoding sulfide : quinone reductase (SQR) in sediment environments. Based on the phylogenetic analysis, we classified the sqr sequences into six groups. PCR primers specific for each group were developed. We successfully amplified sqr-like gene sequences related to groups 1, 2 and 4 from diverse sediments including a marine sediment (SW), a tidal flat (TS), a river sediment (RS) and a lake sediment (FW). We recovered a total of 82 unique phylotypes (based on a 95 % amino acid sequence similarity cutoff) from 243 individual sqr-like gene sequences. Phylotype richness varied widely among the groups of sqr-like gene sequences (group 1>group 2>group 4) and sediments (SW>TS>RS>FW). Most of the sqr-like gene sequences were affiliated with the Proteobacteria clade and were distantly related to the reference sqr gene sequences from cultivated strains (less than approximately 80 % amino acid sequence similarity). Unique sqr-like gene sequences were associated with individual sediment samples in groups 1 and 2. This molecular tool has also enabled us to detect sqr-like genes in a sulfur-oxidizing enrichment from marine sediments. Collectively, our results support the presence of previously unrecognized sqr gene-containing micro-organisms that play important roles in the global biogeochemical cycle of sulfur.
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Affiliation(s)
- Vinh Hoa Pham
- Department of Microbiology, Chungbuk National University, 12 Gaeshin-dong, Heungduk-gu, Cheongju 361-763, Korea
| | - Jeong-Joong Yong
- Department of Microbiology, Chungbuk National University, 12 Gaeshin-dong, Heungduk-gu, Cheongju 361-763, Korea
| | - Soo-Je Park
- Department of Microbiology, Chungbuk National University, 12 Gaeshin-dong, Heungduk-gu, Cheongju 361-763, Korea
| | - Dae-No Yoon
- Department of Microbiology, Chungbuk National University, 12 Gaeshin-dong, Heungduk-gu, Cheongju 361-763, Korea
| | - Won-Hyong Chung
- National Genome Information Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Sung-Keun Rhee
- Department of Microbiology, Chungbuk National University, 12 Gaeshin-dong, Heungduk-gu, Cheongju 361-763, Korea
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Pacheco Aguilar JR, Peña Cabriales JJ, Maldonado Vega M. Identification and characterization of sulfur-oxidizing bacteria in an artificial wetland that treats wastewater from a tannery. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2008; 10:359-370. [PMID: 19260219 DOI: 10.1080/15226510802100390] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Wastewater from tanneries contains high concentrations of organic matter, chromium, nitrogen, and sulfur compounds. In this study, an artificial wetland is is used as the tertiary treatment in a tannery in León Gto., México. It consists of three subplots with an area of about 450 m2. Two subplots were planted with Typha sp. and the third with Scirpus americanus. Geochemical analyses along the flowpath of the wetland show that contaminants were effectively attenuated. The most probable number technique was used to determine rhizospheric microbial populations involved in the sulfur cycle and suggested that there were 104-10(6) cells g(-1) sediment of sulfate-reducing bacteria and 10(2)-10(5) of sulfur-oxidizing bacteria (SOB). Representatives of SOB were isolated on media containing thiosulfate. Phylogenetic analysis of 16S rRNA of SOB isolates shows that they belong to the genera Acinetobacter, Alcaligenes, Ochrobactrum, and Pseudomonas. Most of the isolates are organotrophic and can oxidize reduced sulfur compounds such as elemental sulfur or thiosulfate, accumulating thiosulfate, or tetrathionate during growth. All isolates can use reduced-sulfur compounds as their sole sulfur source and some can use nitrate as an electron acceptor to grow anaerobically. Our results illustrate the relevance of SOB in the functioning of the wetland constructed for tannery wastewater remediation.
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Burgin AJ, Hamilton SK. NO3 −-Driven SO4 2− Production in Freshwater Ecosystems: Implications for N and S Cycling. Ecosystems 2008. [DOI: 10.1007/s10021-008-9169-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Brioukhanov AL, Netrusov AI. Aerotolerance of strictly anaerobic microorganisms and factors of defense against oxidative stress: A review. APPL BIOCHEM MICRO+ 2007. [DOI: 10.1134/s0003683807060014] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Myers JL, Sekar R, Richardson LL. Molecular detection and ecological significance of the cyanobacterial genera Geitlerinema and Leptolyngbya in black band disease of corals. Appl Environ Microbiol 2007; 73:5173-82. [PMID: 17601818 PMCID: PMC1950983 DOI: 10.1128/aem.00900-07] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Black band disease (BBD) is a pathogenic, sulfide-rich microbial mat dominated by filamentous cyanobacteria that infect corals worldwide. We isolated cyanobacteria from BBD into culture, confirmed their presence in the BBD community by using denaturing gradient gel electrophoresis (DGGE), and demonstrated their ecological significance in terms of physiological sulfide tolerance and photosynthesis-versus-irradiance values. Twenty-nine BBD samples were collected from nine host coral species, four of which have not previously been investigated, from reefs of the Florida Keys, the Bahamas, St. Croix, and the Philippines. From these samples, seven cyanobacteria were isolated into culture. Cloning and sequencing of the 16S rRNA gene using universal primers indicated that four isolates were related to the genus Geitlerinema and three to the genus Leptolyngbya. DGGE results, obtained using Cyanobacteria-specific 16S rRNA primers, revealed that the most common BBD cyanobacterial sequence, detected in 26 BBD field samples, was related to that of an Oscillatoria sp. The next most common sequence, 99% similar to that of the Geitlerinema BBD isolate, was present in three samples. One Leptolyngbya- and one Phormidium-related sequence were also found. Laboratory experiments using isolates of BBD Geitlerinema and Leptolyngbya revealed that they could carry out sulfide-resistant oxygenic photosynthesis, a relatively rare characteristic among cyanobacteria, and that they are adapted to the sulfide-rich, low-light BBD environment. The presence of the cyanotoxin microcystin in these cultures and in BBD suggests a role in BBD pathogenicity. Our results confirm the presence of Geitlerinema in the BBD microbial community and its ecological significance, which have been challenged, and provide evidence of a second ecologically significant BBD cyanobacterium, Leptolyngbya.
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Affiliation(s)
- Jamie L Myers
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA.
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Dillon JG, Fishbain S, Miller SR, Bebout BM, Habicht KS, Webb SM, Stahl DA. High rates of sulfate reduction in a low-sulfate hot spring microbial mat are driven by a low level of diversity of sulfate-respiring microorganisms. Appl Environ Microbiol 2007; 73:5218-26. [PMID: 17575000 PMCID: PMC1950965 DOI: 10.1128/aem.00357-07] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The importance of sulfate respiration in the microbial mat found in the low-sulfate thermal outflow of Mushroom Spring in Yellowstone National Park was evaluated using a combination of molecular, microelectrode, and radiotracer studies. Despite very low sulfate concentrations, this mat community was shown to sustain a highly active sulfur cycle. The highest rates of sulfate respiration were measured close to the surface of the mat late in the day when photosynthetic oxygen production ceased and were associated with a Thermodesulfovibrio-like population. Reduced activity at greater depths was correlated with novel populations of sulfate-reducing microorganisms, unrelated to characterized species, and most likely due to both sulfate and carbon limitation.
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Affiliation(s)
- Jesse G Dillon
- Department of Microbiology and NASA Astrobiology Institute, University of Washington, Seattle, Washington 98195, USA.
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Nigro LM, King GM. Disparate distributions of chemolithotrophs containing form IA or IC large subunit genes for ribulose-1,5-bisphosphate carboxylase/oxygenase in intertidal marine and littoral lake sediments. FEMS Microbiol Ecol 2007; 60:113-25. [PMID: 17381527 DOI: 10.1111/j.1574-6941.2007.00272.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The distributions of bacterial form IA and form IC ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) were investigated using Lowes Cove intertidal mudflat and Damariscotta Lake littoral sediments by PCR amplification of 492-495 bp fragments of the large subunit RuBisCO gene, cbbL. Genomic extracts for amplification were obtained from lake surface (upper 2 mm), mudflat surface (upper 2 mm), subsurface (5-7 cm), and soft-shell clam (Mya arenaria) burrow-wall sediments, as well as from a sulfide-oxidizing mat. Phylogenetic analyses of cbbL clone libraries revealed that Lowes Cove sediments were dominated by form IA cbbL-containing sequences most closely related to cbbL genes of sulfur-oxidizing bacteria or sulfide-oxidizing mats. In contrast, Damariscotta Lake cbbL clones contained primarily form IC cbbL sequences, which typify aerobic CO- and hydrogen-oxidizing facultative chemolithotrophs. Statistical analyses supported clear differentiation of intertidal and lake chemolithotroph communities, and provided evidence for some differentiation among intertidal communities. amova and libshuff analyses of Lowes Cove libraries suggested that M. arenaria burrow-wall sediments did not harbour distinct communities compared with surface and subsurface sediments, but that surface and subsurface libraries displayed moderate differences. The results collectively support a conceptual model in which the relative distribution of form IA- and IC-containing bacterial chemolithotrophs depends on sulfide availability, which could reflect the role of sulfate reduction in sediment organic matter metabolism, or the presence of geothermal sulfide sources.
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Affiliation(s)
- Lisa M Nigro
- University of Maine, 193 Clarks Cove Road, Walpole, ME 04573, USA
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Taylor BL, Watts KJ, Johnson MS. Oxygen and Redox Sensing by Two‐Component Systems That Regulate Behavioral Responses: Behavioral Assays and Structural Studies of Aer Using In Vivo Disulfide Cross‐Linking. Methods Enzymol 2007; 422:190-232. [PMID: 17628141 DOI: 10.1016/s0076-6879(06)22010-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A remarkable increase in the number of annotated aerotaxis (oxygen-seeking) and redox taxis sensors can be attributed to recent advances in bacterial genomics. However, in silico predictions should be supported by behavioral assays and genetic analyses that confirm an aerotaxis or redox taxis function. This chapter presents a collection of procedures that have been highly successful in characterizing aerotaxis and redox taxis in Escherichia coli. The methods are described in enough detail to enable investigators of other species to adapt the procedures for their use. A gas flow cell is used to quantitate the temporal responses of bacteria to a step increase or decrease in oxygen partial pressure or redox potential. Bacterial behavior in spatial gradients is analyzed using optically flat capillaries and soft agar plates (succinate agar or tryptone agar). We describe two approaches to estimate the preferred partial pressure of oxygen that attracts a bacterial species; this concentration is important for understanding microbial ecology. At the molecular level, we describe procedures used to determine the structure and topology of Aer, a membrane receptor for aerotaxis. Cysteine-scanning mutagenesis and in vivo disulfide cross-linking procedures utilize the oxidant Cu(II)-(1,10-phenanthroline)(3) and bifunctional sulfhydryl-reactive probes. Finally, we describe methods used to determine the boundaries of transmembrane segments of receptors such as Aer. These include 5-iodoacetamidofluorescein, 4-acetamido-4-disulfonic acid, disodium salt (AMS), and methoxy polyethylene glycol maleimide, a 5-kDa molecular mass probe that alters the mobility of Aer on SDS-PAGE.
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Affiliation(s)
- Barry L Taylor
- Division of Cellular Biology and Molecular Genetics, Loma Linda University, Loma Linda, California, USA
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Edwards JC, Johnson MS, Taylor BL. Differentiation between electron transport sensing and proton motive force sensing by the Aer and Tsr receptors for aerotaxis. Mol Microbiol 2006; 62:823-37. [PMID: 16995896 PMCID: PMC1858650 DOI: 10.1111/j.1365-2958.2006.05411.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Aerotaxis (oxygen-seeking) behaviour in Escherichia coli is a response to changes in the electron transport system and not oxygen per se. Because changes in proton motive force (PMF) are coupled to respiratory electron transport, it is difficult to differentiate between PMF, electron transport or redox, all primary candidates for the signal sensed by the aerotaxis receptors, Aer and Tsr. We constructed electron transport mutants that produced different respiratory H+/e- stoichiometries. These strains expressed binary combinations of one NADH dehydrogenase and one quinol oxidase. We then introduced either an aer or tsr mutation into each mutant to create two sets of electron transport mutants. In vivo H+/e- ratios for strains grown in glycerol medium ranged from 1.46+/-0.18-3.04+/-0.47, but rates of respiration and growth were similar. The PMF jump in response to oxygen was proportional to the H+/e- ratio in each set of mutants (r2=0.986-0.996). The length of Tsr-mediated aerotaxis responses increased with the PMF jump (r2=0.988), but Aer-mediated responses did not correlate with either PMF changes (r2=0.297) or the rate of electron transport (r2=0.066). Aer-mediated responses were linked to NADH dehydrogenase I, although there was no absolute requirement. The data indicate that Tsr responds to changes in PMF, but strong Aer responses to oxygen are associated with redox changes in NADH dehydrogenase I.
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Affiliation(s)
- Jessica C Edwards
- Division of Microbiology and Molecular Genetics, Loma Linda University, Loma Linda, CA 92350, USA
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