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Zheng J, Huang X, Gao L, Xu X, Hou L, Cai T, Jia S. Deciphering the core bacterial community structure and function and their response to environmental factors in activated sludge from pharmaceutical wastewater treatment plants. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 346:123635. [PMID: 38428794 DOI: 10.1016/j.envpol.2024.123635] [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: 12/14/2023] [Revised: 01/29/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024]
Abstract
Pharmaceutical wastewater is recognized for its heightened concentrations of organic pollutants, and biological treatment stands out as an effective technology to remove these organic pollution. Therefore, a comprehensive exploration of core bacterial community compositions, functions, and their responses to environmental factors in pharmaceutical wastewater treatment plants (PWWTPs) is important for understanding the removal mechanism of these organic pollutants. This study comprehensively investigated 36 activated sludge (AS) samples from 15 PWWTPs in China. The results revealed that Proteobacteria (45.41%) was the dominant phylum in AS samples, followed by Bacteroidetes (19.54%) and Chloroflexi (4.13%). While the dominant genera were similar in both aerobic and anaerobic treatment processes, their relative abundances exhibited significant variations. Genera like HA73, Kosmotoga, and Desulfovibrio were more abundant during anaerobic treatment, while Rhodoplanes, Bdellovibrio, and Hyphomicrobium dominated during aerobic treatment. 13 and 10 core operational taxonomic units (OTUs) were identified in aerobic and anaerobic sludge, respectively. Further analysis revealed that core OTUs belonging to genera Kosmotoga, Desulfovibrio, Thauera, Hyphomicrobium, and Chelativorans, were associated with key functions, including sulfur metabolism, methane metabolism, amino acid metabolism, carbohydrate metabolism, toluene degradation, and nitrogen metabolism. Furthermore, this study highlighted the crucial roles of environmental factors, such as COD, NH4+-N, SO42-, and TP, in shaping both the structure and core functions of bacterial communities within AS of PWWTPs. Notably, these factors indirectly affect functional attributes by modulating the bacterial community composition and structure in pharmaceutical wastewater. These findings provide valuable insights for optimizing the efficiency of biochemical treatment processes in PWWTPs.
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Affiliation(s)
- Jinli Zheng
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xin Huang
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Linjun Gao
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xu Xu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Lijun Hou
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Tianming Cai
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shuyu Jia
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
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2
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Kumar Chaudhary D, Bajagain R, Seo D, Hong Y, Han S. Depth-dependent microbial communities potentially mediating mercury methylation and various geochemical processes in anthropogenically affected sediments. ENVIRONMENTAL RESEARCH 2023; 237:116888. [PMID: 37586452 DOI: 10.1016/j.envres.2023.116888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
Metal contamination and other geochemical alterations affect microbial composition and functional activities, disturbing natural biogeochemical cycles. Therefore, it is essential to understand the influences of multi-metal and geochemical interactions on microbial communities. This work investigated the distributions of total mercury (THg), methylmercury (MeHg), and trace metals in the anthropogenically affected sediment. The microbial communities and functional genes profiles were further determined to explore their association with Hg-methylation and geochemical features. The levels of THg and MeHg in sediment cores ranged between 10 and 40 mg/kg and 0.01-0.16 mg/kg, respectively, with an increasing trend toward bottom horizons. The major metals present at all depths were Al, Fe, Mn, and Zn. The enrichment and contamination indices confirmed that the trace metals were highly enriched in the anthropogenically affected sediment. Various functional genes were detected in all strata, indicating the presence of active microbial metabolic processes. The microbial community profiles revealed that the phyla Proteobacteria, Bacteroidetes, Bathyarchaeota, and Euryarchaeota, and the genera Thauera, Woeseia, Methanomethylovorans, and Methanosarcina were the dominant microbes. Correlating major taxa with geochemical variables inferred that sediment geochemistry substantially affects microbial community and biogeochemical cycles. Furthermore, archaeal methanogens and the bacterial phyla Chloroflexi and Firmicutes may play crucial roles in enhancing MeHg levels. Overall, these findings shed new light on the microbial communities potentially involved in Hg-methylation process and other biogeochemical cycles.
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Affiliation(s)
- Dhiraj Kumar Chaudhary
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, Republic of Korea
| | - Rishikesh Bajagain
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, Republic of Korea
| | - DongGyun Seo
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, Republic of Korea
| | - Yongseok Hong
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, Republic of Korea.
| | - Seunghee Han
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
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3
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Zhuo T, He L, Chai B, Zhou S, Wan Q, Lei X, Zhou Z, Chen B. Micro-pressure promotes endogenous phosphorus release in a deep reservoir by favouring microbial phosphate mineralisation and solubilisation coupled with sulphate reduction. WATER RESEARCH 2023; 245:120647. [PMID: 37738938 DOI: 10.1016/j.watres.2023.120647] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 09/10/2023] [Accepted: 09/17/2023] [Indexed: 09/24/2023]
Abstract
Deep reservoirs vary in their hydrostatic pressure owing to artificial water level control. The potential migration of phosphorus (P) in reservoir sediments raises the risk of harmful algal blooms. To ascertain the mechanisms of endogenous P release in reservoirs, we characterised aquatic microbial communities associated with coupled iron (Fe), P and sulphur (S) cycling at the sediment-water interface. The responses of microbial communities to hydrostatic pressures of 0.2-0.7 mega pascals (MPa; that is, micro-pressures) were investigated through a 30-day simulation experiment. Our findings unravelled a potential mechanism that micro-pressure enhanced the solubilisation of Fe/aluminium (Al)-bound P caused by microbially-driven sulphate reduction, leading to endogenous P release in the deep reservoir. Although the vertical distribution of labile Fe was not affected by pressure changes, we did observe Fe resupply at sediment depths of 2-5 cm. Metagenomic analysis revealed increased abundances of functional genes for P mineralisation (phoD, phoA), P solubilisation (pqqC, ppx-gppA) and sulphate reduction (cysD, cysC) in sediments subjected to micro-pressure, which contrasted with the pattern of S oxidation gene (soxB). There was a tight connection between P and S cycling-related microbial communities, based on significant positive correlations between labile element (P and S) concentrations and functional gene (phoD, cysD) abundances. This provided strong support that Fe-P-S coupling processes were governed by micro-pressure through modulation of P and S cycling-related microbial functions. Key taxa involved in P and S cycling (for example, Bradyrhizobium, Methyloceanibacter) positively responded to micro-pressure and as such, indirectly drove P release from sediments by facilitating P mineralisation and solubilisation coupled with sulphate reduction.
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Affiliation(s)
- Tianyu Zhuo
- School of Environmental Science and Engineering, Tianjin University, Jinnan District, Tianjin 300350, China
| | - Lixin He
- Hebei Collaborative Innovation Center for the Regulation and Comprehensive Management of Water Resources and Water Environment, Hebei University of Engineering, Handan 056038, China; Hebei Key Laboratory of Intelligent Water Conservancy, School of Water Conservancy and Hydroelectric, Hebei University of Engineering, Handan 056038, China
| | - Beibei Chai
- Hebei Collaborative Innovation Center for the Regulation and Comprehensive Management of Water Resources and Water Environment, Hebei University of Engineering, Handan 056038, China; Hebei Key Laboratory of Intelligent Water Conservancy, School of Water Conservancy and Hydroelectric, Hebei University of Engineering, Handan 056038, China.
| | - Shilei Zhou
- Pollution Prevention Biotechnology Laboratory of Hebei Province, School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Qiong Wan
- School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an 710054, China
| | - Xiaohui Lei
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China.
| | - Zhenming Zhou
- College of Civil Engineering, Huaqiao University, Xiamen 361021, China
| | - Bin Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China
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4
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Okumura Y, Furutono T, Ito K, Hara M. Influence of submarine topography and sediment environment on microbial assemblages in a coastal lagoon in northeastern Japan. MARINE POLLUTION BULLETIN 2023; 194:115404. [PMID: 37591020 DOI: 10.1016/j.marpolbul.2023.115404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 07/10/2023] [Accepted: 08/06/2023] [Indexed: 08/19/2023]
Abstract
The relationships among eutrophication, anoxia, and microbial distribution were investigated for Nagatsura-Ura Lagoon on the northeastern Pacific coast of Japan. In September 2017, the bottom environment in a small area of the inner part of the lagoon (which has a basin-shaped bottom topology) was eutrophic and anoxic, with high carbon, nitrogen, phosphate, acid-volatile sulfide, and low dissolved oxygen and oxidation-reduction potential. Dissolved oxygen levels improved during the winter. Bacillariophyta (diatoms) were the main organic component according to pigment analysis and next-generation sequencing of nucleic acids in seawater samples. Phylum Proteobacteria was dominant among the bacterial flora in the sediment but the proportions of Class Epsilon-proteobacteria and Chlorobium (a green sulfur-utilizing bacterium) were high in the inner part of the lagoon compared to other stations, and these groups were also present in winter. Apparently groups able to thrive in both anoxic and aerobic conditions were predominant in the inner part of the lagoon.
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Affiliation(s)
- Yutaka Okumura
- Fisheries Resources Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency, 3-27-5 Shinhama, Shiogama, Miyagi 985-0001, Japan.
| | - Tarou Furutono
- IDEA Consultants Inc., 1-1-11, Nishikimachi, Aoba, Sendai, Miyagi 980-0012, Japan
| | - Kinuko Ito
- Graduate School of Agricultural Science, Tohoku University, 468-1, Aramaki, Aoba, Aoba, Sendai, Miyagi 980-0845 Japan
| | - Motoyuki Hara
- Graduate School of Agricultural Science, Tohoku University, 468-1, Aramaki, Aoba, Aoba, Sendai, Miyagi 980-0845 Japan
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Zhang X, Paoletti MM, Izon G, Fournier GP, Summons RE. Late acquisition of the rTCA carbon fixation pathway by Chlorobi. Nat Ecol Evol 2023; 7:1398-1407. [PMID: 37537385 DOI: 10.1038/s41559-023-02147-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/30/2023] [Indexed: 08/05/2023]
Abstract
The reverse tricarboxylic acid (rTCA) cycle is touted as a primordial mode of carbon fixation due to its autocatalytic propensity and oxygen intolerance. Despite this inferred antiquity, however, the earliest rock record affords scant supporting evidence. In fact, based on the chimeric inheritance of rTCA cycle steps within the Chlorobiaceae, even the use of the chemical fossil record of this group is now subject to question. While the 1.64-billion-year-old Barney Creek Formation contains chemical fossils of the earliest known putative Chlorobiaceae-derived carotenoids, interferences from the accompanying hydrocarbon matrix have hitherto precluded the carbon isotope measurements necessary to establish the physiology of the organisms that produced them. Overcoming this obstacle, here we report a suite of compound-specific carbon isotope measurements identifying a cyanobacterially dominated ecosystem featuring heterotrophic bacteria. We demonstrate chlorobactane is 13C-depleted when compared to contemporary equivalents, showing only slight 13C-enrichment over co-existing cyanobacterial carotenoids. The absence of this diagnostic isotopic fingerprint, in turn, confirms phylogenomic hypotheses that call for the late assembly of the rTCA cycle and, thus, the delayed acquisition of autotrophy within the Chlorobiaceae. We suggest that progressive oxygenation of the Earth System caused an increase in the marine sulfate inventory thereby providing the selective pressure to fuel the Neoproterozoic shift towards energy-efficient photoautotrophy within the Chlorobiaceae.
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Affiliation(s)
- Xiaowen Zhang
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, China.
| | - Madeline M Paoletti
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gareth Izon
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gregory P Fournier
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
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6
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Xu F, Guan J, Zhou Y, Song Z, Shen Y, Liu Y, Jia X, Zhang B, Guo P. Effects of freeze-thaw dynamics and microplastics on the distribution of antibiotic resistance genes in soil aggregates. CHEMOSPHERE 2023; 329:138678. [PMID: 37059196 DOI: 10.1016/j.chemosphere.2023.138678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
This is the first study investigating the effects of freeze-thaw (FT) and microplastics (MPs) on the distribution of antibiotic resistance genes (ARGs) in soil aggregates (i.e., soil basic constituent and functional unit) via microcosm experiments. The results showed that FT significantly increased the total relative abundance of target ARGs in different aggregates due to the increase in intI1 and ARG host bacteria. However, polyethylene MPs (PE-MPs) hindered the increase in ARG abundance caused by FT. The host bacteria carrying ARGs and intI1 varied with aggregate size, and the highest number of hosts was observed in micro-aggregates (<0.25 mm). FT and MPs altered host bacteria abundance by affecting aggregate physicochemical properties and bacterial community and enhanced multiple antibiotic resistance via vertical gene transfer. Although the dominant factors affecting ARGs varied with aggregate size, intI1 was a co-dominant factor in various-sized aggregates. Furthermore, other than ARGs, FT, PE-MPs, and their integration promoted the proliferation of human pathogenic bacteria in aggregates. These findings suggested that FT and its integration with MPs significantly affected ARG distribution in soil aggregates. They amplified antibiotic resistance environmental risks, contributing to a profound understanding of soil antibiotic resistance in the boreal region.
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Affiliation(s)
- Fukai Xu
- Key Laboratory of Groundwater Resources and Environment Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130012, PR China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, 130012, PR China
| | - Jiunian Guan
- School of Environment, Northeast Normal University, Changchun, 130117, PR China
| | - Yumei Zhou
- Shanghai Institute of Technology, Shanghai, 201418, PR China
| | - Ziwei Song
- Key Laboratory of Groundwater Resources and Environment Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130012, PR China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, 130012, PR China
| | - Yanping Shen
- Key Laboratory of Groundwater Resources and Environment Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130012, PR China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, 130012, PR China
| | - Yibo Liu
- Key Laboratory of Groundwater Resources and Environment Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130012, PR China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, 130012, PR China
| | - Xiaohui Jia
- Key Laboratory of Groundwater Resources and Environment Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130012, PR China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, 130012, PR China
| | - Baiyu Zhang
- Department of Civil Engineering, Faculty of Engineering and Applied Science, Memorial University, St. John's, NL, A1B 3X5, Canada.
| | - Ping Guo
- Key Laboratory of Groundwater Resources and Environment Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130012, PR China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, 130012, PR China.
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7
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Hu L, Wang Y, Ci M, Long Y. Unravelling microbial drivers of the sulfate-reduction process inside landfill using metagenomics. CHEMOSPHERE 2023; 313:137537. [PMID: 36521740 DOI: 10.1016/j.chemosphere.2022.137537] [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: 09/05/2022] [Revised: 11/25/2022] [Accepted: 12/10/2022] [Indexed: 06/17/2023]
Abstract
Hydrogen sulfide (H2S) is one of the common landfill odor. This research demonstrates that the sulfate transformation behavior is significantly enhanced during the landfill process, accompanied by a shift in microbial structure. The relative abundance of dissimilatory sulfate reduction (DSR) and thiosulfate oxidation by SOX (sulfur-oxidation) complex gradually decreases through the landfill processes while the assimilatory sulfate reduction (ASR) demonstrates the opposite behavior. The major module for landfill sulfate reduction is ASR, accounting for 31.72% ± 2.84% of sulfate metabolism. Based on the functional genes for the sulfate pathway, the drivers for sulfate biotransformation in landfills were determined and further identified their contribution in the sulfate metabolism during landfill processes. Pseudomonas, Methylocaldum, Bacillus, Methylocystis and Hyphomicrobium were the top 5 contributors for ASR pathway, and only one genus Pseudomonas was found for DSR pathway. Among the 26 high-quality metagenome-assembled genomes of sulfate functional species, 24 were considered novel species for sulfuric metabolism. Overall, this study provides unique insight into the sulfate transformation process related to the H2S odor control in landfill management.
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Affiliation(s)
- Lifang Hu
- College of Quality and Safety Engineering, Institution of Industrial Carbon Metrology, China Jiliang University, Hangzhou, 310018, China
| | - Yuqian Wang
- College of Quality and Safety Engineering, Institution of Industrial Carbon Metrology, China Jiliang University, Hangzhou, 310018, China
| | - Manting Ci
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Instrumental Analysis Center, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China
| | - Yuyang Long
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Instrumental Analysis Center, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
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8
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Ward LM, Shih PM. Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen. PLoS One 2022; 17:e0270187. [PMID: 35913911 PMCID: PMC9342728 DOI: 10.1371/journal.pone.0270187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 06/07/2022] [Indexed: 11/28/2022] Open
Abstract
While most productivity on the surface of the Earth today is fueled by oxygenic photosynthesis, for much of Earth history it is thought that anoxygenic photosynthesis-using compounds like ferrous iron or sulfide as electron donors-drove most global carbon fixation. Anoxygenic photosynthesis is still performed by diverse bacteria in niche environments today. Of these, the Chlorobi (formerly green sulfur bacteria) are often interpreted as being particularly ancient and are frequently proposed to have fueled the biosphere during late Archean and early Paleoproterozoic time before the rise of oxygenic photosynthesis. Here, we perform comparative genomic, phylogenetic, and molecular clock analyses to determine the antiquity of the Chlorobi and their characteristic phenotypes. We show that contrary to common assumptions, the Chlorobi clade is relatively young, with anoxygenic phototrophy, carbon fixation via the rTCA pathway, and iron oxidation all significantly postdating the rise of oxygen ~2.3 billion years ago. The Chlorobi therefore could not have fueled the Archean biosphere, but instead represent a relatively young radiation of organisms which likely acquired the capacity for anoxygenic photosynthesis and other traits via horizontal gene transfer sometime after the evolution of oxygenic Cyanobacteria.
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Affiliation(s)
- L. M. Ward
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Geosciences, Smith College, Northampton, Massachusetts, United States of America
| | - Patrick M. Shih
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, United States of America
- Feedstocks Division, Joint BioEnergy Institute, Emeryville, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, California, United States of America
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9
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Lambrecht N, Stevenson Z, Sheik CS, Pronschinske MA, Tong H, Swanner ED. " Candidatus Chlorobium masyuteum," a Novel Photoferrotrophic Green Sulfur Bacterium Enriched From a Ferruginous Meromictic Lake. Front Microbiol 2021; 12:695260. [PMID: 34305861 PMCID: PMC8302410 DOI: 10.3389/fmicb.2021.695260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/07/2021] [Indexed: 11/13/2022] Open
Abstract
Anoxygenic phototrophic bacteria can be important primary producers in some meromictic lakes. Green sulfur bacteria (GSB) have been detected in ferruginous lakes, with some evidence that they are photosynthesizing using Fe(II) as an electron donor (i.e., photoferrotrophy). However, some photoferrotrophic GSB can also utilize reduced sulfur compounds, complicating the interpretation of Fe-dependent photosynthetic primary productivity. An enrichment (BLA1) from meromictic ferruginous Brownie Lake, Minnesota, United States, contains an Fe(II)-oxidizing GSB and a metabolically flexible putative Fe(III)-reducing anaerobe. "Candidatus Chlorobium masyuteum" grows photoautotrophically with Fe(II) and possesses the putative Fe(II) oxidase-encoding cyc2 gene also known from oxygen-dependent Fe(II)-oxidizing bacteria. It lacks genes for oxidation of reduced sulfur compounds. Its genome encodes for hydrogenases and a reverse TCA cycle that may allow it to utilize H2 and acetate as electron donors, an inference supported by the abundance of this organism when the enrichment was supplied by these substrates and light. The anaerobe "Candidatus Pseudopelobacter ferreus" is in low abundance (∼1%) in BLA1 and is a putative Fe(III)-reducing bacterium from the Geobacterales ord. nov. While "Ca. C. masyuteum" is closely related to the photoferrotrophs C. ferroooxidans strain KoFox and C. phaeoferrooxidans strain KB01, it is unique at the genomic level. The main light-harvesting molecule was identified as bacteriochlorophyll c with accessory carotenoids of the chlorobactene series. BLA1 optimally oxidizes Fe(II) at a pH of 6.8, and the rate of Fe(II) oxidation was 0.63 ± 0.069 mmol day-1, comparable to other photoferrotrophic GSB cultures or enrichments. Investigation of BLA1 expands the genetic basis for phototrophic Fe(II) oxidation by GSB and highlights the role these organisms may play in Fe(II) oxidation and carbon cycling in ferruginous lakes.
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Affiliation(s)
- Nicholas Lambrecht
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
| | - Zackry Stevenson
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
| | - Cody S. Sheik
- Department of Biology, University of Minnesota Duluth, Duluth, MN, United States
- Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN, United States
| | - Matthew A. Pronschinske
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
| | - Hui Tong
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Institute of Eco-environmental Science and Technology, Guangdong Academy of Sciences, Guangzhou, China
| | - Elizabeth D. Swanner
- Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA, United States
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10
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Rego ES, Busigny V, Lalonde SV, Philippot P, Bouyon A, Rossignol C, Babinski M, de Cássia Zapparoli A. Anoxygenic photosynthesis linked to Neoarchean iron formations in Carajás (Brazil). GEOBIOLOGY 2021; 19:326-341. [PMID: 33660904 DOI: 10.1111/gbi.12438] [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: 10/14/2020] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 06/12/2023]
Abstract
Microbial activity is often invoked as a direct or indirect contributor to the precipitation of ancient chemical sedimentary rocks such as Precambrian iron formations (IFs). Determining a specific metabolic pathway from the geological record remains a challenge, however, due to a lack of constraints on the initial conditions and microbially induced redox reactions involved in the formation of iron oxides. Thus, there is ongoing debate concerning the role of photoferrotrophy, that is the process by which inorganic carbon is fixed into organic matter using light as an energy source and Fe(II) as an electron donor, in the deposition of IFs. Here, we examine ~2.74-Ga-old Neoarchean IFs and associated carbonates from the Carajás Mineral Province, Brazil, to reconstruct redox conditions and to infer the oxidizing mechanism that allowed one of the world's largest iron deposits to form. The absence of cerium (Ce) anomalies reveals that conditions were pervasively anoxic during IF deposition, while unprecedented europium (Eu) anomalies imply that Fe was supplied by intense hydrothermal activity. A positive and homogeneous Fe isotopic signal in space and time in these IFs indicates a low degree of partial oxidation of Fe(II), which, combined with the presence of 13 C-depleted organic matter, points to a photoautotrophic metabolic driver. Collectively, our results argue in favor of reducing conditions during IF deposition and suggest anoxygenic photosynthesis as the most plausible mechanism responsible for Fe oxidation in the Carajás Basin.
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Affiliation(s)
- Eric Siciliano Rego
- Instituto de Geociências, Universidade de São Paulo, Cidade Universitária, São Paulo, Brazil
- Institut de Physique du Globe de Paris, Université de Paris, CNRS, Paris cedex 05, France
- Géosciences Montpellier, Université de Montpellier, CNRS, Université des Antilles, Montpellier, France
| | - Vincent Busigny
- Institut de Physique du Globe de Paris, Université de Paris, CNRS, Paris cedex 05, France
| | - Stefan V Lalonde
- Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, CNRS, Plouzané, France
| | - Pascal Philippot
- Institut de Physique du Globe de Paris, Université de Paris, CNRS, Paris cedex 05, France
- Géosciences Montpellier, Université de Montpellier, CNRS, Université des Antilles, Montpellier, France
- Departamento de Geofísica, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Cidade Universitária, São Paulo, Brazil
| | - Amaury Bouyon
- Géosciences Montpellier, Université de Montpellier, CNRS, Université des Antilles, Montpellier, France
| | - Camille Rossignol
- Institut de Physique du Globe de Paris, Université de Paris, CNRS, Paris cedex 05, France
- Departamento de Geofísica, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Cidade Universitária, São Paulo, Brazil
| | - Marly Babinski
- Instituto de Geociências, Universidade de São Paulo, Cidade Universitária, São Paulo, Brazil
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11
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Tsuji JM, Tran N, Schiff SL, Venkiteswaran JJ, Molot LA, Tank M, Hanada S, Neufeld JD. Anoxygenic photosynthesis and iron-sulfur metabolic potential of Chlorobia populations from seasonally anoxic Boreal Shield lakes. THE ISME JOURNAL 2020; 14:2732-2747. [PMID: 32747714 PMCID: PMC7784702 DOI: 10.1038/s41396-020-0725-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/02/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022]
Abstract
Aquatic environments with high levels of dissolved ferrous iron and low levels of sulfate serve as an important systems for exploring biogeochemical processes relevant to the early Earth. Boreal Shield lakes, which number in the tens of millions globally, commonly develop seasonally anoxic waters that become iron rich and sulfate poor, yet the iron-sulfur microbiology of these systems has been poorly examined. Here we use genome-resolved metagenomics and enrichment cultivation to explore the metabolic diversity and ecology of anoxygenic photosynthesis and iron/sulfur cycling in the anoxic water columns of three Boreal Shield lakes. We recovered four high-completeness and low-contamination draft genome bins assigned to the class Chlorobia (formerly phylum Chlorobi) from environmental metagenome data and enriched two novel sulfide-oxidizing species, also from the Chlorobia. The sequenced genomes of both enriched species, including the novel "Candidatus Chlorobium canadense", encoded the cyc2 gene that is associated with photoferrotrophy among cultured Chlorobia members, along with genes for phototrophic sulfide oxidation. One environmental genome bin also encoded cyc2. Despite the presence of cyc2 in the corresponding draft genome, we were unable to induce photoferrotrophy in "Ca. Chlorobium canadense". Genomic potential for phototrophic sulfide oxidation was more commonly detected than cyc2 among environmental genome bins of Chlorobia, and metagenome and cultivation data suggested the potential for cryptic sulfur cycling to fuel sulfide-based growth. Overall, our results provide an important basis for further probing the functional role of cyc2 and indicate that anoxygenic photoautotrophs in Boreal Shield lakes could have underexplored photophysiology pertinent to understanding Earth's early microbial communities.
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Affiliation(s)
- J M Tsuji
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - N Tran
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - S L Schiff
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - J J Venkiteswaran
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
- Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON, N2L 3C5, Canada
| | - L A Molot
- York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - M Tank
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH, Inhoffenstrasse 7B, 38124, Braunschweig, Germany
- Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan
| | - S Hanada
- Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan
| | - J D Neufeld
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada.
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12
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Fernandez L, Peura S, Eiler A, Linz AM, McMahon KD, Bertilsson S. Diazotroph Genomes and Their Seasonal Dynamics in a Stratified Humic Bog Lake. Front Microbiol 2020; 11:1500. [PMID: 32714313 PMCID: PMC7341956 DOI: 10.3389/fmicb.2020.01500] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 06/09/2020] [Indexed: 12/28/2022] Open
Abstract
Aquatic N-fixation is generally associated with the growth and mass development of Cyanobacteria in nitrogen-deprived photic zones. However, sequenced genomes and environmental surveys suggest active aquatic N-fixation also by many non-cyanobacterial groups. Here, we revealed the seasonal variation and genomic diversity of potential N-fixers in a humic bog lake using metagenomic data and nif gene clusters analysis. Groups with diazotrophic operons were functionally divergent and included Cholorobi, Geobacter, Desulfobacterales, Methylococcales, and Acidobacteria. In addition to nifH (a gene that encodes the dinitrogenase reductase component of the molybdenum nitrogenase), we also identified sequences corresponding to vanadium and iron-only nitrogenase genes. Within the Chlorobi population, the nitrogenase (nifH) cluster was included in a well-structured retrotransposon. Furthermore, the presence of light-harvesting photosynthesis genes implies that anoxygenic photosynthesis may fuel nitrogen fixation under the prevailing low-irradiance conditions. The presence of rnf genes (related to the expression of H+/Na+-translocating ferredoxin: NAD+ oxidoreductase) in Methylococcales and Desulfobacterales suggests that other energy-generating processes may drive the costly N-fixation in the absence of photosynthesis. The highly reducing environment of the anoxic bottom layer of Trout Bog Lake may thus also provide a suitable niche for active N-fixers and primary producers. While future studies on the activity of these potential N-fixers are needed to clarify their role in freshwater nitrogen cycling, the metagenomic data presented here enabled an initial characterization of previously overlooked diazotrophs in freshwater biomes.
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Affiliation(s)
- Leyden Fernandez
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Alexander Eiler
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.,Centre for Biogeochemistry in the Anthropocene, Department of Biosciences, Section for Aquatic Biology and Toxicology, University of Oslo, Oslo, Norway
| | - Alexandra M Linz
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Katherine D McMahon
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.,Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
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13
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Feed Types Driven Differentiation of Microbial Community and Functionality in Marine Integrated Multitrophic Aquaculture System. WATER 2019. [DOI: 10.3390/w12010095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Integrated multi trophic aquaculture (IMTA) improves the production of aquatic animals by promoting nutrient utilization through different tropical levels. Microorganisms play an important role in elements cycling, energy flow and farmed-species health. The aim of this study was to evaluate how feed types, fresh frozen fish diet (FFD) or formulated diet (FD), influence the microbial community diversity and functionality in both water and sediment in a marine IMTA system. Preferable water quality, higher animal yields and higher cost efficiency were achieved in the FD pond. Feed types changed the pond bacterial community distribution, especially in the rearing water. The FFD pond was dominated with Cyanobacteria in the water, which played an important role in nitrogen fixation through photosynthesis due to the high nitrogen input of the frozen fish diet. The high carbohydrate composition in the formulated diet triggered higher metabolic pathways related to carbon and lipid metabolism in the water of the FD pond. Sediment had significantly higher microbial diversity than the rearing water. In sediment, the dominating genus, Sulfurovum and Desulfobulbus, were found to be positively correlated by network analysis, which had similar functionality in sulfur transformation. The relatively higher rates of antibiotic biosynthesis in the FFD sediment might be related to the pathogenic bacteria introduced by the trash fish diet. The difference in microbial community composition and metabolic pathways may be associated with the different pathways for nutrient cycling and animal growth performance. The formulated diet was determined to be more ecologically and economically sustainable than the frozen fish diet for marine IMTA pond systems.
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14
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Ozaki K, Thompson KJ, Simister RL, Crowe SA, Reinhard CT. Anoxygenic photosynthesis and the delayed oxygenation of Earth's atmosphere. Nat Commun 2019; 10:3026. [PMID: 31289261 PMCID: PMC6616575 DOI: 10.1038/s41467-019-10872-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/28/2019] [Indexed: 12/03/2022] Open
Abstract
The emergence of oxygenic photosynthesis created a new niche with dramatic potential to transform energy flow through Earth's biosphere. However, more primitive forms of photosynthesis that fix CO2 into biomass using electrons from reduced species like Fe(II) and H2 instead of water would have competed with Earth's early oxygenic biosphere for essential nutrients. Here, we combine experimental microbiology, genomic analyses, and Earth system modeling to demonstrate that competition for light and nutrients in the surface ocean between oxygenic phototrophs and Fe(II)-oxidizing, anoxygenic photosynthesizers (photoferrotrophs) translates into diminished global photosynthetic O2 release when the ocean interior is Fe(II)-rich. These results provide a simple ecophysiological mechanism for inhibiting atmospheric oxygenation during Earth's early history. We also find a novel positive feedback within the coupled C-P-O-Fe cycles that can lead to runaway planetary oxygenation as rising atmospheric pO2 sweeps the deep ocean of the ferrous iron substrate for photoferrotrophy.
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Affiliation(s)
- Kazumi Ozaki
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, CA, USA
- NASA Postdoctoral Program, Universities Space Research Association, Columbia, MD, 21046, USA
- Department of Environmental Science, Toho University, Funabashi, Chiba, 274-8510, Japan
| | - Katharine J Thompson
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Rachel L Simister
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Sean A Crowe
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Christopher T Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, CA, USA.
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15
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Bryce C, Blackwell N, Schmidt C, Otte J, Huang YM, Kleindienst S, Tomaszewski E, Schad M, Warter V, Peng C, Byrne JM, Kappler A. Microbial anaerobic Fe(II) oxidation - Ecology, mechanisms and environmental implications. Environ Microbiol 2018; 20:3462-3483. [DOI: 10.1111/1462-2920.14328] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/15/2018] [Accepted: 06/16/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Casey Bryce
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Nia Blackwell
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | | | - Julia Otte
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Yu-Ming Huang
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | | | | | - Manuel Schad
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Viola Warter
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Chao Peng
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - James M. Byrne
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Andreas Kappler
- Geomicrobiology; University of Tübingen; Tübingen Germany
- Center for Geomicrobiology, Department of Bioscience; Aarhus University; Aarhus Denmark
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16
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Proteome Response of a Metabolically Flexible Anoxygenic Phototroph to Fe(II) Oxidation. Appl Environ Microbiol 2018; 84:AEM.01166-18. [PMID: 29915106 DOI: 10.1128/aem.01166-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 06/07/2018] [Indexed: 11/20/2022] Open
Abstract
The oxidation of Fe(II) by anoxygenic photosynthetic bacteria was likely a key contributor to Earth's biosphere prior to the evolution of oxygenic photosynthesis and is still found in a diverse range of modern environments. All known phototrophic Fe(II) oxidizers can utilize a wide range of substrates, thus making them very metabolically flexible. However, the underlying adaptations required to oxidize Fe(II), a potential stressor, are not completely understood. We used a combination of quantitative proteomics and cryogenic transmission electron microscopy (cryo-TEM) to compare cells of Rhodopseudomonas palustris TIE-1 grown photoautotrophically with Fe(II) or H2 and photoheterotrophically with acetate. We observed unique proteome profiles for each condition, with differences primarily driven by carbon source. However, these differences were not related to carbon fixation but to growth and light harvesting processes, such as pigment synthesis. Cryo-TEM showed stunted development of photosynthetic membranes in photoautotrophic cultures. Growth on Fe(II) was characterized by a response typical of iron homeostasis, which included an increased abundance of proteins required for metal efflux (particularly copper) and decreased abundance of iron import proteins, including siderophore receptors, with no evidence of further stressors, such as oxidative damage. This study suggests that the main challenge facing anoxygenic phototrophic Fe(II) oxidizers comes from growth limitations imposed by autotrophy, and, once this challenge is overcome, iron stress can be mitigated using iron management mechanisms common to diverse bacteria (e.g., by control of iron influx and efflux).IMPORTANCE The cycling of iron between redox states leads to the precipitation and dissolution of minerals, which can in turn impact other major biogeochemical cycles, such as those of carbon, nitrogen, phosphorus and sulfur. Anoxygenic phototrophs are one of the few drivers of Fe(II) oxidation in anoxic environments and are thought to contribute significantly to iron cycling in both modern and ancient environments. These organisms thrive at high Fe(II) concentrations, yet the adaptations required to tolerate the stresses associated with this are unclear. Despite the general consensus that high Fe(II) concentrations pose numerous stresses on these organisms, our study of the large-scale proteome response of a model anoxygenic phototroph to Fe(II) oxidation demonstrates that common iron homeostasis strategies are adequate to manage this. The bulk of the proteome response is not driven by adaptations to Fe(II) stress but to adaptations required to utilize an inorganic carbon source. Such a global overview of the adaptation of these organisms to Fe(II) oxidation provides valuable insights into the physiology of these biogeochemically important organisms and suggests that Fe(II) oxidation may not pose as many challenges to anoxygenic phototrophs as previously thought.
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17
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Otte JM, Harter J, Laufer K, Blackwell N, Straub D, Kappler A, Kleindienst S. The distribution of active iron‐cycling bacteria in marine and freshwater sediments is decoupled from geochemical gradients. Environ Microbiol 2018; 20:2483-2499. [DOI: 10.1111/1462-2920.14260] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Julia M. Otte
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
| | - Johannes Harter
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
| | - Katja Laufer
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
- Center for Geomicrobiology, Department of BioscienceAarhus University Denmark
| | - Nia Blackwell
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
| | - Daniel Straub
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
- Center for Geomicrobiology, Department of BioscienceAarhus University Denmark
| | - Sara Kleindienst
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
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18
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Gustave W, Yuan ZF, Sekar R, Chang HC, Zhang J, Wells M, Ren YX, Chen Z. Arsenic mitigation in paddy soils by using microbial fuel cells. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 238:647-655. [PMID: 29614474 DOI: 10.1016/j.envpol.2018.03.085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/06/2018] [Accepted: 03/24/2018] [Indexed: 05/10/2023]
Abstract
Arsenic (As) behavior in paddy soils couples with the redox process of iron (Fe) minerals. When soil is flooded, Fe oxides are transformed to soluble ferrous ions by accepting the electrons from Fe reducers. This process can significantly affect the fate of As in paddy fields. In this study, we show a novel technique to manipulate the Fe redox processes in paddy soils by deploying soil microbial fuel cells (sMFC). The results showed that the sMFC bioanode can significantly decrease the release of Fe and As into soil porewater. Iron and As contents around sMFC anode were 65.0% and 47.0% of the control respectively at day 50. The observed phenomenon would be explained by a competition for organic substrate between sMFC bioanode and the iron- and arsenic-reducing bacteria in the soils. In the vicinity of bioanode, organic matter removal efficiencies were 10.3% and 14.0% higher than the control for lost on ignition carbon and total organic carbon respectively. Sequencing of the 16S rRNA genes suggested that the influence of bioanodes on bulk soil bacterial community structure was minimal. Moreover, during the experiment a maximum current and power density of 0.31 mA and 12.0 mWm-2 were obtained, respectively. This study shows a novel way to limit the release of Fe and As in soils porewater and simultaneously generate electricity.
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Affiliation(s)
- Williamson Gustave
- Department of Environmental Science, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China; Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool, L69 7ZX, United Kingdom
| | - Zhao-Feng Yuan
- Department of Environmental Science, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China; Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool, L69 7ZX, United Kingdom
| | - Raju Sekar
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, China
| | - Hu-Cheng Chang
- Department of Environmental Science, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China
| | - Jun Zhang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Mona Wells
- Department of Environmental Science, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China
| | - Yu-Xiang Ren
- Department of Environmental Science, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China
| | - Zheng Chen
- Department of Environmental Science, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China.
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19
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Björn LO. Photoenzymes and Related Topics: An Update. Photochem Photobiol 2018; 94:459-465. [PMID: 29441583 DOI: 10.1111/php.12892] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/20/2017] [Indexed: 12/11/2022]
Abstract
Photoenzymes are enzymes that catalyze photochemical reactions. For a long time, it was believed that only two types of photoenzymes exist: light-dependent NADPH:protochlorophyllide oxidoreductase and photolyase. However, other photoenzymes have now been discovered, most recently fatty acid photodecarboxylase.
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