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Hird K, Campeciño JO, Lehnert N, Hegg EL. Recent mechanistic developments for cytochrome c nitrite reductase, the key enzyme in the dissimilatory nitrate reduction to ammonium pathway. J Inorg Biochem 2024; 256:112542. [PMID: 38631103 DOI: 10.1016/j.jinorgbio.2024.112542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/19/2024] [Accepted: 03/23/2024] [Indexed: 04/19/2024]
Abstract
Cytochrome c nitrite reductase, NrfA, is a soluble, periplasmic pentaheme cytochrome responsible for the reduction of nitrite to ammonium in the Dissimilatory Nitrate Reduction to Ammonium (DNRA) pathway, a vital reaction in the global nitrogen cycle. NrfA catalyzes this six-electron and eight-proton reduction of nitrite at a single active site with the help of its quinol oxidase partners. In this review, we summarize the latest progress in elucidating the reaction mechanism of ammonia production, including new findings about the active site architecture of NrfA, as well as recent results that elucidate electron transfer and storage in the pentaheme scaffold of this enzyme.
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Affiliation(s)
- Krystina Hird
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Julius O Campeciño
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Eric L Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA.
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2
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Zhang H, Cheng Y, Qiu L, Zeng W, Hu T, Yang J, Wang J, Wang H, Gong W, Liang H. In situ electron generation through Fe/C supported sludge coupled with a counter-diffusion biofilm for electron-deficient wastewater treatment: Binding properties and catalytic competition mechanism of nitrate reductase. WATER RESEARCH 2024; 257:121688. [PMID: 38723349 DOI: 10.1016/j.watres.2024.121688] [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: 01/31/2024] [Revised: 04/15/2024] [Accepted: 04/27/2024] [Indexed: 05/29/2024]
Abstract
A membrane-aerated biofilm-coupled Fe/C supported sludge system (MABR-Fe/C) was constructed to achieve in situ electron production for NO3--N reduction enhancement in different Fe/C loadings (10 g and 200 g). The anoxic environment formed in the MABR-Fe/C promoted a continual Fe2+release of Fe/C in 120 d operation (average Fe2+concentrations is 1.18 and 2.95 mg/L in MABR-Fe/C10 and MABR-Fe/C200, respectively). Metagenomics results suggested that the electrons generated from ongoing Fe2+ oxidation were transferred via the Quinone pool to EC 1.7.5.1 rather than EC 1.9.6.1 to complete the process of NO3--N reduction to NO2--N in Acidovorax, Ottowia, and Polaromonas. In the absence of organic matter, the NO3--N removal in MABR-Fe/C10 and MABR-Fe/C200 increased by 11.99 and 12.52 mg/L, respectively, compared to that in MABR. In the further NO2--N reduction, even if the minimum binding free energy (MBFE) was low, NO2--N in Acidovorax and Dechloromonas preferentially bind the Gln-residues for dissimilatory nitrate reduction (DNR) in the presence of Fe/C. Increasing Fe/C loading (MABR-Fe/C200) caused the formation of different residue binding sites, further enhancing the already dominant DNR. When DNR in MABR-Fe/C200 intensified, the TN in the effluent increased by 3.75 mg/L although the effluent NO3--N concentration was lower than that in MABR-Fe/C10. This study demonstrated a new MABR-Fe/C system for in situ electron generation to enhance biological nitrogen removal and analyzed the NO3--N reduction pathway and metabolic mechanism, thus providing new ideas for nitrogen removal in electron-deficient wastewater.
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Affiliation(s)
- Han Zhang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Yufei Cheng
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Linhong Qiu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Weichen Zeng
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Tianyi Hu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Jiaxuan Yang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Jinlong Wang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Hesong Wang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Weijia Gong
- School of Engineering, Northeast Agricultural University, 600 Changjiang Street, Xiangfang District, Harbin, 150030, PR China
| | - Heng Liang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China.
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3
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Kaviraj M, Kumar U, Snigdha A, Chatterjee S. Nitrate reduction to ammonium: a phylogenetic, physiological, and genetic aspects in Prokaryotes and eukaryotes. Arch Microbiol 2024; 206:297. [PMID: 38861039 DOI: 10.1007/s00203-024-04009-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 05/15/2024] [Accepted: 05/16/2024] [Indexed: 06/12/2024]
Abstract
The microbe-mediated conversion of nitrate (NO3-) to ammonium (NH4+) in the nitrogen cycle has strong implications for soil health and crop productivity. The role of prokaryotes, eukaryotes and their phylogeny, physiology, and genetic regulations are essential for understanding the ecological significance of this empirical process. Several prokaryotes (bacteria and archaea), and a few eukaryotes (fungi and algae) are reported as NO3- reducers under certain conditions. This process involves enzymatic reactions which has been catalysed by nitrate reductases, nitrite reductases, and NH4+-assimilating enzymes. Earlier reports emphasised that single-cell prokaryotic or eukaryotic organisms are responsible for this process, which portrayed a prominent gap. Therefore, this study revisits the similarities and uniqueness of mechanism behind NO3- -reduction to NH4+ in both prokaryotes and eukaryotes. Moreover, phylogenetic, physiological, and genetic regulation also shed light on the evolutionary connections between two systems which could help us to better explain the NO3--reduction mechanisms over time. Reports also revealed that certain transcription factors like NtrC/NtrB and Nit2 have shown a major role in coordinating the expression of NO3- assimilation genes in response to NO3- availability. Overall, this review provides a comprehensive information about the complex fermentative and respiratory dissimilatory nitrate reduction to ammonium (DNRA) processes. Uncovering the complexity of this process across various organisms may further give insight into sustainable nitrogen management practices and might contribute to addressing global environmental challenges.
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Affiliation(s)
- Megha Kaviraj
- ICAR- National Rice Research Institute, Cuttack, 753006, Odisha, India.
- The University of Burdwan, Burdwan, 713104, West Bengal, India.
| | - Upendra Kumar
- ICAR- National Rice Research Institute, Cuttack, 753006, Odisha, India.
| | - Alisha Snigdha
- Siksha 'O' Anusandhan University, Bhubaneswar, 751003, Odisha, India
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4
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Cerda Á, Rodríguez C, González M, González H, Serrano J, Leiva E. Feammox bacterial biofilm formation in HFMB. CHEMOSPHERE 2024; 358:142072. [PMID: 38657691 DOI: 10.1016/j.chemosphere.2024.142072] [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: 11/16/2023] [Revised: 04/08/2024] [Accepted: 04/16/2024] [Indexed: 04/26/2024]
Abstract
Nitrogen pollution has been increasing with the development of industrialization. Consequently, the excessive deposition of reactive nitrogen in the environment has generated the loss of biodiversity and eutrophication of different ecosystems. In 2005, a Feammox process was discovered that anaerobically metabolizes ammonium. Feammox with the use of hollow fiber membrane bioreactors (HFMB), based on the formation of biofilms of bacterial communities, has emerged as a possible efficient and sustainable method for ammonium removal in environments with high iron concentrations. This work sought to study the possibility of implementing, at laboratory scale, an efficient method by evaluating the use of HFMB. Samples from an internal circulation reactor (IC) incubated in culture media for Feammox bacteria. The cultures were enriched in a batch reactor to evaluate growth conditions. Next, HFMB assembly was performed, and Feammox parameters were monitored. Also, conventional PCR and scanning electron microscopy (SEM) analysis were performed to characterize the bacterial communities associated with biofilm formation. The use of sodium acetate presented the best performance for Feammox activity. The HFMB operation showed an ammonium (NH4+) removal of 50%. SEM analysis of the fibers illustrated the formation of biofilm networks formed by bacteria, which were identified as Albidiferax ferrireducens, Geobacter spp, Ferrovum myxofaciens, Shewanella spp., and Anammox. Functional genes Archaea/Bacteria ammonia monooxygenase, nrxA, hzsB, nirS and nosZ were also identified. The implementation of HFMB Feammox could be used as a sustainable tool for the removal of ammonium from wastewater produced because of anthropogenic activities.
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Affiliation(s)
- Ámbar Cerda
- Departamento de Química Inorgánica, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, 7820436, Santiago, Chile.
| | - Carolina Rodríguez
- Departamento de Química Inorgánica, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, 7820436, Santiago, Chile.
| | - Macarena González
- Departamento de Química Inorgánica, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, 7820436, Santiago, Chile.
| | - Heylin González
- Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, 7820436, Santiago, Chile.
| | - Jennyfer Serrano
- Escuela de Biotecnología, Universidad Mayor, Camino La Pirámide 5750, Huechuraba, Santiago 8580745, Chile.
| | - Eduardo Leiva
- Departamento de Química Inorgánica, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, 7820436, Santiago, Chile; Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Macul, 7820436, Santiago, Chile.
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5
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Saghaï A, Hallin S. Diversity and ecology of NrfA-dependent ammonifying microorganisms. Trends Microbiol 2024; 32:602-613. [PMID: 38462391 DOI: 10.1016/j.tim.2024.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/11/2024] [Accepted: 02/13/2024] [Indexed: 03/12/2024]
Abstract
Nitrate ammonifiers are a taxonomically diverse group of microorganisms that reduce nitrate to ammonium, which is released, and thereby contribute to the retention of nitrogen in ecosystems. Despite their importance for understanding the fate of nitrate, they remain a largely overlooked group in the nitrogen cycle. Here, we present the latest advances on free-living microorganisms using NrfA to reduce nitrite during ammonification. We describe their diversity and ecology in terrestrial and aquatic environments, as well as the environmental factors influencing the competition for nitrate with denitrifiers that reduce nitrate to gaseous nitrogen species, including the greenhouse gas nitrous oxide (N2O). We further review the capacity of ammonifiers for other redox reactions, showing that they likely play multiple roles in the cycling of elements.
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Affiliation(s)
- Aurélien Saghaï
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sara Hallin
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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Liu Y, Xu L, Su J, Ali A, Huang T, Wang Y, Zhang P. Microbially driven Fe-N cycle: Intrinsic mechanisms, enhancement, and perspectives. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168084. [PMID: 37924885 DOI: 10.1016/j.scitotenv.2023.168084] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/21/2023] [Accepted: 10/21/2023] [Indexed: 11/06/2023]
Abstract
The iron‑nitrogen (FeN) cycle driven by microbes has great potential for treating wastewater. Fe is a metal that is frequently present in the environment and one of the crucial trace elements needed by microbes. Due to its synergistic role in the microbial N removal process, Fe goes much beyond the essential nutritional needs of microorganisms. Investigating the mechanisms behind the linked Fe-N cycle driven by microbes is crucial. The Fe-N cycle is frequently connected with anaerobic ammonia oxidation (anammox), nitrification, denitrification, dissimilatory nitrate reduction to ammonium (DNRA), Feammox, and simultaneous nitrification denitrification (SND), etc. Although the main mechanisms of Fe-mediated biological N removal may vary depending on the valence state of the Fe, their similar transformation pathways may provide information on the study of certain element-microbial interactions. This review offers a thorough analysis of the facilitation effect and influence of Fe on the removal of nitrogenous pollutants in various biological N removal processes and summarizes the ideal Fe dosing. Additionally, the synergistic mechanisms of Fe and microbial synergistic N removal process are elaborated, covering four aspects: enzyme activity, electron transfer, microbial extracellular polymeric substances (EPS) secretion, and microbial community interactions. The methods to improve biological N removal based on the intrinsic mechanism were also discussed, with the aim of thoroughly understanding the biological mechanisms of Fe in the microbial N removal process and providing a reference and thinking for employing Fe to promote microbial N removal in practical applications.
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Affiliation(s)
- Yan Liu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Liang Xu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Amjad Ali
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tinglin Huang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yue Wang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Peng Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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7
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Mosley OE, Gios E, Handley KM. Implications for nitrogen and sulphur cycles: phylogeny and niche-range of Nitrospirota in terrestrial aquifers. ISME COMMUNICATIONS 2024; 4:ycae047. [PMID: 38650708 PMCID: PMC11033732 DOI: 10.1093/ismeco/ycae047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/20/2024] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
Increasing evidence suggests Nitrospirota are important contributors to aquatic and subsurface nitrogen and sulphur cycles. We determined the phylogenetic and ecological niche associations of Nitrospirota colonizing terrestrial aquifers. Nitrospirota compositions were determined across 59 groundwater wells. Distributions were strongly influenced by oxygen availability in groundwater, marked by a trade-off between aerobic (Nitrospira, Leptospirillum) and anaerobic (Thermodesulfovibrionia, unclassified) lineages. Seven Nitrospirota metagenome-assembled genomes (MAGs), or populations, were recovered from a subset of wells, including three from the recently designated class 9FT-COMBO-42-15. Most were relatively more abundant and transcriptionally active in dysoxic groundwater. These MAGs were analysed with 743 other Nitrospirota genomes. Results illustrate the predominance of certain lineages in aquifers (e.g. non-nitrifying Nitrospiria, classes 9FT-COMBO-42-15 and UBA9217, and Thermodesulfovibrionales family UBA1546). These lineages are characterized by mechanisms for nitrate reduction and sulphur cycling, and, excluding Nitrospiria, the Wood-Ljungdahl pathway, consistent with carbon-limited, low-oxygen, and sulphur-rich aquifer conditions. Class 9FT-COMBO-42-15 is a sister clade of Nitrospiria and comprises two families spanning a transition in carbon fixation approaches: f_HDB-SIOIB13 encodes rTCA (like Nitrospiria) and f_9FT-COMBO-42-15 encodes Wood-Ljungdahl CO dehydrogenase (like Thermodesulfovibrionia and UBA9217). The 9FT-COMBO-42-15 family is further differentiated by its capacity for sulphur oxidation (via DsrABEFH and SoxXAYZB) and dissimilatory nitrate reduction to ammonium, and gene transcription indicated active coupling of nitrogen and sulphur cycles by f_9FT-COMBO-42-15 in dysoxic groundwater. Overall, results indicate that Nitrospirota are widely distributed in groundwater and that oxygen availability drives the spatial differentiation of lineages with ecologically distinct roles related to nitrogen and sulphur metabolism.
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Affiliation(s)
- Olivia E Mosley
- School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
- Present address: NatureMetrics Ltd, Surrey Research Park, Guildford GU2 7HJ, United Kingdom
| | - Emilie Gios
- School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
- Present address: NINA, Norwegian Institute for Nature Research, Trondheim 7034, Norway
| | - Kim M Handley
- School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
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Saghaï A, Pold G, Jones CM, Hallin S. Phyloecology of nitrate ammonifiers and their importance relative to denitrifiers in global terrestrial biomes. Nat Commun 2023; 14:8249. [PMID: 38086813 PMCID: PMC10716430 DOI: 10.1038/s41467-023-44022-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
Nitrate ammonification is important for soil nitrogen retention. However, the ecology of ammonifiers and their prevalence compared with denitrifiers, being competitors for nitrate, are overlooked. Here, we screen 1 million genomes for nrfA and onr, encoding ammonifier nitrite reductases. About 40% of ammonifier assemblies carry at least one denitrification gene and show higher potential for nitrous oxide production than consumption. We then use a phylogeny-based approach to recruit gene fragments of nrfA, onr and denitrification nitrite reductase genes (nirK, nirS) in 1861 global terrestrial metagenomes. nrfA outnumbers the nearly negligible onr counts in all biomes, but denitrification genes dominate, except in tundra. Random forest modelling teases apart the influence of the soil C/N on nrfA-ammonifier vs denitrifier abundance, showing an effect of nitrate rather than carbon content. This study demonstrates the multiple roles nitrate ammonifiers play in nitrogen cycling and identifies factors ultimately controlling the fate of soil nitrate.
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Affiliation(s)
- Aurélien Saghaï
- Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology, Uppsala, Sweden
| | - Grace Pold
- Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology, Uppsala, Sweden
| | - Christopher M Jones
- Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology, Uppsala, Sweden
| | - Sara Hallin
- Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology, Uppsala, Sweden.
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Yang Z, Yang Z, Zhan Y, Hu C, Zhang Z, He M, Huang J, Wang J, Yin H, Liu Z. Optimizing SCND with carbon-rich hydrolysates from typical organic wastes: Material composition, augmentation performance, microbiome response, and life cycle impact. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 340:117966. [PMID: 37116417 DOI: 10.1016/j.jenvman.2023.117966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/22/2023] [Accepted: 04/16/2023] [Indexed: 05/12/2023]
Abstract
The rapid growth of production and consumption has led to severe environmental pollution, creating a major challenge to achieving the United Nations' sustainable development goals (SDGs). To address it, recycling of organic wastes into value-added products is a possible solution. In this work, four typical organic wastes including sewage sludge (SS), chicken manure (CM), food waste (FW), and corn straw (CS) were employed to produce hydrolysates augmenting shortcut nitrification-denitrification (SCND) for nitrogen depletion in wastewater. The hydrolysates were carbon-rich, with total COD (TCOD), soluble COD (SCOD), and volatile fatty acids (VFA) concentrations ranging from 32.5 to 102.7, 5.7 to 48.4, and 2.0-16.5 mg/L, respectively. The most effective nitrogen depletion was obtained in units supplemented with CM and FW hydrolysates, which had reduced average NH3-N concentrations and near-zero TN removal failure rates under legal requirements. The microbial community analysis demonstrated that various functional bacteria from phylum to genus level were detected in all scenarios, which was corroborated by abundant genetic functions involved in nitrogen metabolism. Further, life cycle assessment revealed negative environmental impact on all categories, with an exception of eutrophication potential (EP) with negative values (∼-0.04 kg Phosphate eq.), allowing positive net environmental benefit (NEB). Operational cost analysis revealed that CM and FW are more effective but costlier than SS and CS. Together, these results indicate that, after hydrolysis, organic wastes can be efficient stimulant augmenting SCND performance for nitrogen depletion in wastewater, benefiting the overall environmental impact.
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Affiliation(s)
- Zhendong Yang
- School of Architecture and Civil Engineering, Chengdu University, Chengdu, 610106, Sichuan, China; Sichuan Provincial Engineering Research Center of City Solid Waste Energy and Building Materials Conversion and Utilization Technology, Chengdu, 610106, Sichuan, China
| | - Zhaoyue Yang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, Hunan, China
| | - Yazhi Zhan
- School of Architecture and Civil Engineering, Chengdu University, Chengdu, 610106, Sichuan, China
| | - Cheng Hu
- School of Architecture and Civil Engineering, Chengdu University, Chengdu, 610106, Sichuan, China
| | - Zhenyu Zhang
- School of Architecture and Civil Engineering, Chengdu University, Chengdu, 610106, Sichuan, China
| | - Miao He
- School of Architecture and Civil Engineering, Chengdu University, Chengdu, 610106, Sichuan, China
| | - Jin Huang
- School of Architecture and Civil Engineering, Chengdu University, Chengdu, 610106, Sichuan, China; Sichuan Provincial Engineering Research Center of City Solid Waste Energy and Building Materials Conversion and Utilization Technology, Chengdu, 610106, Sichuan, China
| | - Jing Wang
- School of Architecture and Civil Engineering, Chengdu University, Chengdu, 610106, Sichuan, China; Sichuan Provincial Engineering Research Center of City Solid Waste Energy and Building Materials Conversion and Utilization Technology, Chengdu, 610106, Sichuan, China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, Hunan, China
| | - Zhenghua Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, Hunan, China.
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10
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Jiang H, Chen GF, Savateev O, Xue J, Ding LX, Liang Z, Antonietti M, Wang H. Enabled Efficient Ammonia Synthesis and Energy Supply in a Zinc-Nitrate Battery System by Separating Nitrate Reduction Process into Two Stages. Angew Chem Int Ed Engl 2023; 62:e202218717. [PMID: 36728627 DOI: 10.1002/anie.202218717] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/03/2023]
Abstract
The aqueous electrocatalytic reduction of NO3 - into NH3 (NitrRR) presents a sustainable route applicable to NH3 production and potentially energy storage. However, the NitrRR involves a directly eight-electron transfer process generally required a large overpotential (<-0.2 V versus reversible hydrogen electrode (vs. RHE)) to reach optimal efficiency. Here, inspired by biological nitrate respiration, the NitrRR was separated into two stages along a [2+6]-electron pathway to alleviate the kinetic barrier. The system employed a Cu nanowire catalyst produces NO2 - and NH3 with current efficiencies of 91.5 % and 100 %, respectively at lower overpotentials (>+0.1 vs. RHE). The high efficiency for such a reduction process was further explored in a zinc-nitrate battery. This battery could be specified by a high output voltage of 0.70 V, an average energy density of 566.7 Wh L-1 at 10 mA cm-2 and a power density of 14.1 mW cm-2 , which is well beyond all previously reported similar concepts.
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Affiliation(s)
- Haifeng Jiang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China.,Beijing Key Laboratory for Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Gao-Feng Chen
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China.,Department of Colloid Chemistry, Max-Planck Institute of Colloids and Interfaces, Research Campus Golm, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Oleksandr Savateev
- Department of Colloid Chemistry, Max-Planck Institute of Colloids and Interfaces, Research Campus Golm, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Jian Xue
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Liang-Xin Ding
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Zhenxing Liang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Markus Antonietti
- Department of Colloid Chemistry, Max-Planck Institute of Colloids and Interfaces, Research Campus Golm, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Haihui Wang
- Beijing Key Laboratory for Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
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11
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Lycus P, Einsle O, Zhang L. Structural biology of proteins involved in nitrogen cycling. Curr Opin Chem Biol 2023; 74:102278. [PMID: 36889028 DOI: 10.1016/j.cbpa.2023.102278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 03/08/2023]
Abstract
Microbial metabolic processes drive the global nitrogen cycle through sophisticated and often unique metalloenzymes that facilitate difficult redox reactions at ambient temperature and pressure. Understanding the intricacies of these biological nitrogen transformations requires a detailed knowledge that arises from the combination of a multitude of powerful analytical techniques and functional assays. Recent developments in spectroscopy and structural biology have provided new, powerful tools for addressing existing and emerging questions, which have gained urgency due to the global environmental implications of these fundamental reactions. The present review focuses on the recent contributions of the wider area of structural biology to understanding nitrogen metabolism, opening new avenues for biotechnological applications to better manage and balance the challenges of the global nitrogen cycle.
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Affiliation(s)
- Pawel Lycus
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104, Freiburg im Breisgau, Germany; Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Oliver Einsle
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104, Freiburg im Breisgau, Germany.
| | - Lin Zhang
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104, Freiburg im Breisgau, Germany.
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12
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Sharma G, Garg N, Hasan S, Saffarini D, Shirodkar S. Fumarate and nitrite reduction by Prevotella nigrescens and Prevotella buccae isolated from Chronic Periodontitis patients. Microb Pathog 2023; 176:106022. [PMID: 36739100 DOI: 10.1016/j.micpath.2023.106022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
OBJECTIVE This study is an investigation of anaerobic nitrite and fumarate reduction/respiration abilities of two characterised Prevotella species namely Prevotella nigrescens (SS6B) and Prevotella buccae (GS6B) isolated from the periodontal pockets of chronic periodontitis (ChP) patients. METHODS Isolation and identification of the periodontal bacteria from 20 patients showing clinical symptoms of ChP. Characterisation of anaerobic nitrite and fumarate reduction was done in P. nigrescens (SS6B) and P. buccae (GS6B) using reduction assays, inhibition assays with use of specific inhibitors, growth assays and enzyme activity assays. Degenerate PCR was used to detect and amplify nitrite reductase (nrfA) and fumarate reductase (frdA) gene sequences in these Prevotella isolates. In addition, molecular and in silico analysis of the amplified anaerobic reductase gene sequences was performed using NCBI conserved domain analysis, Interpro database and MegaX. RESULTS We provided experimental evidence for presence of active nitrite and fumarate reductase activities through enzyme activity, reduction, inhibitor and growth assays. Moreover, we were able to detect presence of 505 bps nrfA gene fragment and 400 bps frdA gene fragment in these Prevotella spp. These fragments show similarity to multiheme ammonia forming cytochrome c nitrite reductases and fumarate reductases flavoprotein subunit, respectively. CONCLUSION Anaerobic nitrite and fumarate respiration abilities in P. nigrescens and P. buccae isolates appear to be important for detoxification process and growth, respectively.
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Affiliation(s)
- Geetika Sharma
- Amity Institute of Biotechnology, Amity University Uttar Pradesh Noida Campus, Noida, 201313, India
| | - Nancy Garg
- Amity Institute of Biotechnology, Amity University Uttar Pradesh Noida Campus, Noida, 201313, India
| | - Shamimul Hasan
- Department of Oral Medicine and Radiology, Faculty of Dentistry, Jamia Millia Islamia, New Delhi, 110025, India
| | - Daad Saffarini
- Department of Biological Sciences, University of Wisconsin Milwaukee, 3209 N. Maryland Ave Milwaukee, WI, 53211, USA
| | - Sheetal Shirodkar
- Amity Institute of Biotechnology, Amity University Uttar Pradesh Noida Campus, Noida, 201313, India.
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13
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Homology modeling and virtual characterization of cytochrome c nitrite reductase (NrfA) in three model bacteria responsible for short-circuit pathway, DNRA in the terrestrial nitrogen cycle. World J Microbiol Biotechnol 2022; 38:168. [DOI: 10.1007/s11274-022-03352-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/04/2022] [Indexed: 11/26/2022]
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14
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Almeida K, Santos G, Daniel J, Nino-de-Guzman C, Amaro F, Sultana H, Arriola K, Araujo R, Vyas D. Effects of nitrate sources on in vitro methane production and ruminal fermentation parameters in diets differing in starch degradability. Anim Feed Sci Technol 2022. [DOI: 10.1016/j.anifeedsci.2022.115437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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15
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16
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Zhao Y, Zhao G. Decreasing ruminal methane production through enhancing the sulfate reduction pathway. ANIMAL NUTRITION 2022; 9:320-326. [PMID: 35600554 PMCID: PMC9097629 DOI: 10.1016/j.aninu.2022.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/28/2021] [Accepted: 01/25/2022] [Indexed: 11/17/2022]
Abstract
Methane (CH4) production from ruminants accounts for 16% of the global greenhouse gas emissions and represents 2% to 12% of feed energy. Mitigating CH4 production from ruminants is of great importance for sustainable development of the ruminant industry. H2 is the primary substrate for CH4 production in the processes of ruminal methanogenesis. Sulfate reducing bacteria are able to compete with methanogens for H2 in the rumen, and consequently inhibit the methanogenesis. Enhancing the ruminal sulfate reducing pathway is an important approach to mitigate CH4 emissions in ruminants. The review summarized the effects of sulfate and elemental S on ruminal methanogenesis, and clarified the related mechanisms through the impacts of sulfate and elemental S on major ruminal sulfate reducing bacteria. Enhancing the activities of the major ruminal sulfate reducing bacteria including Desulfovibrio, Desulfohalobium and Sulfolobus through dietary sulfate addition, elemental S and dried distillers grains with solubles can effectively decrease the ruminal CH4 emissions. Suitable levels of dietary addition with different S sources for reducing the ruminal CH4 production, as well as maintaining the performance and health of ruminants, need to be investigated in the future.
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17
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Spring S, Rohde M, Bunk B, Spröer C, Will SE, Neumann-Schaal M. New insights into the energy metabolism and taxonomy of Deferribacteres revealed by the characterization of a new isolate from a hypersaline microbial mat. Environ Microbiol 2022; 24:2543-2575. [PMID: 35415868 DOI: 10.1111/1462-2920.15999] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/04/2022] [Indexed: 12/13/2022]
Abstract
Strain L21-Ace-BEST , isolated from a lithifying cyanobacterial mat, could be assigned to a novel species and genus within the Deferribacteres. It is an important model organism for the study of anaerobic acetate degradation under hypersaline conditions. The metabolism of strain L21-Ace-BEST was characterized by biochemical studies, comparative genome analyses, and the evaluation of gene expression patterns. The central metabolic pathway is the citric acid cycle, which is mainly controlled by the enzyme succinyl-CoA:acetate-CoA transferase. The potential use of a reversed oxidative citric acid cycle to fix CO2 has been revealed through genome analysis. However, no autotrophic growth was detected in this strain, whereas sulfide and H2 can be used mixotrophically. Preferred electron acceptors for the anaerobic oxidation of acetate are nitrate, fumarate and DMSO, while oxygen can be utilized only under microoxic conditions. Aerotolerant growth by fermentation was observed at higher oxygen concentrations. The redox cycling of sulfur/sulfide enables the generation of reducing power for the assimilation of acetate during growth and could prevent the over-reduction of cells in stationary phase. Extracellular electron transfer appears to be an essential component of the respiratory metabolism in this clade of Deferribacteres and may be involved in the reduction of nitrite to ammonium. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Stefan Spring
- Department Microorganisms, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, HZI, Braunschweig, Germany
| | - Boyke Bunk
- Department Bioinformatics, Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Department Bioinformatics, Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Sabine Eva Will
- Research Group Metabolomics, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Meina Neumann-Schaal
- Research Group Metabolomics, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
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18
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Wang B, Peng Q, Wang R, Yu S, Li Q, Huang C. Efficient Microcystis removal and sulfonamide-resistance gene propagation mitigation by constructed wetlands and functional genes analysis. CHEMOSPHERE 2022; 292:133481. [PMID: 34990722 DOI: 10.1016/j.chemosphere.2021.133481] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/24/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
Increasingly prevalent Microcystis blooms and the propagation of the associated resistance genes represent global environmental problems. Constructed wetlands (CWs) are a cost-effective technology used for wastewater treatment. In this study, the herb Alisma orientale and three industrial byproducts, namely, blast furnace slag, biochar, and sawdust, were selected to construct mini-CW units. Their potential to remediate toxic Microcystis and their influences on the behaviors of antibiotic-resistant genes (ARGs, sul1, sul2, and intl1) were analyzed. Approximately 98.46% of Microcystis cells were removed by the sawdust-based CW in just 2 d, wherein <0.37 μg/L residual microcystin (MC)-LR was detected, with a removal efficiency of >96.47%, which is potentially caused by the higher relative abundance of MC-degrading gene mlrA on the substrate. Lower target ARG accumulations in the sawdust-based CW may be attributed to the lower intl1 relative abundance and microbial function mobile element content, which could influence horizontal gene transfer. In three sequential batches for the treatment of eutrophic lake water, six sawdust-based CW units were assembled into CW microcosms. The efficiency of removal of Microcystis and MC-LR by planted CW microcosms ranged between 92.00% and 95.88% and between 86.48% and 94.82%, respectively; this was significantly (P < 0.05) higher than that by unplanted ones. Less accumulation of target ARGs was also observed in planted CWs. Planting considerably improved nitrogen removal, possibly owing to the enrichment of genes involved in the KEGG nitrogen metabolism pathway in the substrate through metagenomic analysis.
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Affiliation(s)
- Bo Wang
- College of Life Science, Sichuan Normal University, Chengdu, 610041, China
| | - Qin Peng
- College of Life Science, Sichuan Normal University, Chengdu, 610041, China
| | - Rui Wang
- College of Life Science, Sichuan Normal University, Chengdu, 610041, China; Plant Functional Genomics and Bioinformatics Research Center, Sichuan Normal University, Chengdu, 610041, China; Institute of Application and Development of Plant Resources, Sichuan Normal University, Chengdu, 610041, China.
| | - Shuhua Yu
- College of Life Science, Sichuan Normal University, Chengdu, 610041, China; Plant Functional Genomics and Bioinformatics Research Center, Sichuan Normal University, Chengdu, 610041, China; Institute of Application and Development of Plant Resources, Sichuan Normal University, Chengdu, 610041, China
| | - Qi Li
- College of Life Science, Sichuan Normal University, Chengdu, 610041, China; Plant Functional Genomics and Bioinformatics Research Center, Sichuan Normal University, Chengdu, 610041, China; Institute of Application and Development of Plant Resources, Sichuan Normal University, Chengdu, 610041, China
| | - Chunping Huang
- College of Life Science, Sichuan Normal University, Chengdu, 610041, China; Plant Functional Genomics and Bioinformatics Research Center, Sichuan Normal University, Chengdu, 610041, China; Institute of Application and Development of Plant Resources, Sichuan Normal University, Chengdu, 610041, China
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19
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Lehnert N, Kim E, Dong HT, Harland JB, Hunt AP, Manickas EC, Oakley KM, Pham J, Reed GC, Alfaro VS. The Biologically Relevant Coordination Chemistry of Iron and Nitric Oxide: Electronic Structure and Reactivity. Chem Rev 2021; 121:14682-14905. [PMID: 34902255 DOI: 10.1021/acs.chemrev.1c00253] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nitric oxide (NO) is an important signaling molecule that is involved in a wide range of physiological and pathological events in biology. Metal coordination chemistry, especially with iron, is at the heart of many biological transformations involving NO. A series of heme proteins, nitric oxide synthases (NOS), soluble guanylate cyclase (sGC), and nitrophorins, are responsible for the biosynthesis, sensing, and transport of NO. Alternatively, NO can be generated from nitrite by heme- and copper-containing nitrite reductases (NIRs). The NO-bearing small molecules such as nitrosothiols and dinitrosyl iron complexes (DNICs) can serve as an alternative vehicle for NO storage and transport. Once NO is formed, the rich reaction chemistry of NO leads to a wide variety of biological activities including reduction of NO by heme or non-heme iron-containing NO reductases and protein post-translational modifications by DNICs. Much of our understanding of the reactivity of metal sites in biology with NO and the mechanisms of these transformations has come from the elucidation of the geometric and electronic structures and chemical reactivity of synthetic model systems, in synergy with biochemical and biophysical studies on the relevant proteins themselves. This review focuses on recent advancements from studies on proteins and model complexes that not only have improved our understanding of the biological roles of NO but also have provided foundations for biomedical research and for bio-inspired catalyst design in energy science.
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Affiliation(s)
- Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eunsuk Kim
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Hai T Dong
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jill B Harland
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Andrew P Hunt
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Elizabeth C Manickas
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Kady M Oakley
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - John Pham
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Garrett C Reed
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Victor Sosa Alfaro
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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20
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Kroneck PMH. Nature's nitrite-to-ammonia expressway, with no stop at dinitrogen. J Biol Inorg Chem 2021; 27:1-21. [PMID: 34865208 PMCID: PMC8840924 DOI: 10.1007/s00775-021-01921-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/22/2021] [Indexed: 12/26/2022]
Abstract
Since the characterization of cytochrome c552 as a multiheme nitrite reductase, research on this enzyme has gained major interest. Today, it is known as pentaheme cytochrome c nitrite reductase (NrfA). Part of the NH4+ produced from NO2- is released as NH3 leading to nitrogen loss, similar to denitrification which generates NO, N2O, and N2. NH4+ can also be used for assimilatory purposes, thus NrfA contributes to nitrogen retention. It catalyses the six-electron reduction of NO2- to NH4+, hosting four His/His ligated c-type hemes for electron transfer and one structurally differentiated active site heme. Catalysis occurs at the distal side of a Fe(III) heme c proximally coordinated by lysine of a unique CXXCK motif (Sulfurospirillum deleyianum, Wolinella succinogenes) or, presumably, by the canonical histidine in Campylobacter jejeuni. Replacement of Lys by His in NrfA of W. succinogenes led to a significant loss of enzyme activity. NrfA forms homodimers as shown by high resolution X-ray crystallography, and there exist at least two distinct electron transfer systems to the enzyme. In γ-proteobacteria (Escherichia coli) NrfA is linked to the menaquinol pool in the cytoplasmic membrane through a pentaheme electron carrier (NrfB), in δ- and ε-proteobacteria (S. deleyianum, W. succinogenes), the NrfA dimer interacts with a tetraheme cytochrome c (NrfH). Both form a membrane-associated respiratory complex on the extracellular side of the cytoplasmic membrane to optimize electron transfer efficiency. This minireview traces important steps in understanding the nature of pentaheme cytochrome c nitrite reductases, and discusses their structural and functional features.
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Affiliation(s)
- Peter M H Kroneck
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
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21
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Distribution of Dissolved Nitrogen Compounds in the Water Column of a Meromictic Subarctic Lake. NITROGEN 2021. [DOI: 10.3390/nitrogen2040029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In order to better understand the biogeochemical cycle of nitrogen in meromictic lakes, which can serve as a model for past aquatic environments, we measured dissolved concentrations of nitrate, nitrite, ammonium, and organic nitrogen in the deep (39 m maximal depth) subarctic Lake Svetloe (NW Russia). The lake is a rare type of freshwater meromictic water body with high concentrations of methane, ferrous iron, and manganese and low concentrations of sulfates and sulfides in the monimolimnion. In the oligotrophic mixolimnion, the concentration of mineral forms of nitrogen decreased in summer compared to winter, likely due to a phytoplankton bloom. The decomposition of the bulk of the organic matter occurs under microaerophilic/anaerobic conditions of the chemocline and is accompanied by the accumulation of nitrogen in the form of N-NH4 in the monimolimnion. We revealed a strong relationship between methane and nitrogen cycles in the chemocline and monimolimnion horizons. The nitrate concentrations in Lake Svetloe varied from 9 to 13 μM throughout the water column. This fact is rare for meromictic lakes, where nitrate concentrations up to 13 µM are found in the monimolimnion zone down to the bottom layers. We hypothesize, in accord with available data for other stratified lakes that under conditions of high concentrations of manganese and ammonium at the boundary of redox conditions and below, anaerobic nitrification with the formation of nitrate occurs. Overall, most of the organic matter in Lake Svetloe undergoes biodegradation essentially under microaerophilic/anaerobic conditions of the chemocline and the monimolimnion. Consequently, the manifestation of the biogeochemical nitrogen cycle is expressed in these horizons in the most vivid and complex relationship with other cycles of elements.
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Hu Y, Hong Y, Ye J, Wu J, Wang Y, Ye F, Chang X, Long A. Shift of DNRA bacterial community composition in sediment cores of the Pearl River Estuary and the impact of environmental factors. ECOTOXICOLOGY (LONDON, ENGLAND) 2021; 30:1689-1703. [PMID: 33411163 DOI: 10.1007/s10646-020-02321-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
Dissimilatory nitrate reduction to ammonia (DNRA) process, competing with denitrification and anaerobic ammonia oxidation (anammox) for nitrate, is an important nitrogen retention pathway in the environment. Previous studies on DNRA bacterial diversity and composition focused on the surface sediments in estuaries, but studies on the deep sediments are limited, and the linkage between DNRA community structure and complex estuarine environment remains unclear. In this study, through high-throughput sequencing of nrfA gene followed by high-resolution sample inference, we examined spatially and temporally the composition and diversity of DNRA bacteria along a salinity gradient in five sediment cores of the Pearl River Estuary (PRE). We found a higher diversity and richness of DNRA bacteria in sediments with lower organic carbon, where sea water intersects fresh water. Moreover, the DNRA bacterial communities had the specific spatially distribution coupling with their metabolic difference along the salinity gradient of the Pearl River Estuary, but no obvious difference along the sediment depth. The distribution of DNRA bacteria in the PRE was largely driven by various environmental factors, including salinity, Oxidation-Reduction Potential (ORP), ammonium, nitrate and Corg/NO3-. Furthermore, dominant DNRA bacteria were found to be the key populations of DNRA communities in the PRE sediments by network analysis. Collectively, our results showed that niche difference of DNRA bacteria indeed occurs in the Pearl River Estuary.
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Affiliation(s)
- Yaohao Hu
- State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510301, Guangzhou, PR China
- University of Chinese Academy of Sciences, 100049, Beijing, PR China
| | - Yiguo Hong
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, 510006, Guangzhou, PR China.
- School of Environmental Science and Engineering, Guangzhou University, 510006, Guangzhou, PR China.
| | - Jiaqi Ye
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, 510006, Guangzhou, PR China
- School of Environmental Science and Engineering, Guangzhou University, 510006, Guangzhou, PR China
| | - Jiapeng Wu
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, 510006, Guangzhou, PR China
| | - Yu Wang
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, 510006, Guangzhou, PR China
| | - Fei Ye
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, 510006, Guangzhou, PR China
| | - Xiangyang Chang
- School of Environmental Science and Engineering, Guangzhou University, 510006, Guangzhou, PR China
| | - Aimin Long
- State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510301, Guangzhou, PR China.
- University of Chinese Academy of Sciences, 100049, Beijing, PR China.
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Shahid S, Ali M, Legaspi-Humiston D, Wilcoxen J, Pacheco AA. A Kinetic Investigation of the Early Steps in Cytochrome c Nitrite Reductase (ccNiR)-Catalyzed Reduction of Nitrite. Biochemistry 2021; 60:2098-2115. [PMID: 34143605 DOI: 10.1021/acs.biochem.1c00172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The decaheme enzyme cytochrome c nitrite reductase (ccNiR) catalyzes reduction of nitrite to ammonium in a six-electron, eight-proton process. With a strong reductant as the electron source, ammonium is the sole product. However, intermediates accumulate when weaker reductants are employed, facilitating study of the ccNiR mechanism. Herein, the early stages of Shewanella oneidensis ccNiR-catalyzed nitrite reduction were investigated by using the weak reductants N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) and ferrocyanide. In stopped-flow experiments, reduction of nitrite-loaded ccNiR by TMPD generated a transient intermediate, identified as FeH1II(NO2-), where FeH1 represents the ccNiR active site. FeH1II(NO2-) accumulated rapidly and was then more slowly converted to the two-electron-reduced moiety {FeH1NO}7; ccNiR was not reduced beyond the {FeH1NO}7 state. The midpoint potentials for sequential reduction of FeH1III(NO2-) to FeH1II(NO2-) and then to {FeH1NO}7 were estimated to be 130 and 370 mV versus the standard hydrogen electrode, respectively. FeH1II(NO2-) does not accumulate at equilibrium because its reduction to {FeH1NO}7 is so much easier than the reduction of FeH1III(NO2-) to FeH1II(NO2-). With weak reductants, free NO• was released from nitrite-loaded ccNiR. The release of NO• from {FeH1NO}7 is exceedingly slow (k ∼ 0.001 s-1), but it is somewhat faster (k ∼ 0.050 s-1) while FeH1III(NO2-) is being reduced to {FeH1NO}7; then, the release of NO• from the undetectable transient {FeH1NO}6 can compete with reduction of {FeH1NO}6 to {FeH1NO}7. CcNiR appears to be optimized to capture nitrite and minimize the release of free NO•. Nitrite capture is achieved by reducing bound nitrite with even weak electron donors, while NO• release is minimized by stabilizing the substitutionally inert {FeH1NO}7 over the more labile {FeH1NO}6.
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Affiliation(s)
- Shahid Shahid
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Mahbbat Ali
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Desiree Legaspi-Humiston
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Jarett Wilcoxen
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - A Andrew Pacheco
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
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24
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Sosa Alfaro V, Campeciño J, Tracy M, Elliott SJ, Hegg EL, Lehnert N. Elucidating Electron Storage and Distribution within the Pentaheme Scaffold of Cytochrome c Nitrite Reductase (NrfA). Biochemistry 2021; 60:1853-1867. [PMID: 34061493 DOI: 10.1021/acs.biochem.0c00977] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cytochrome c nitrite reductases (CcNIR or NrfA) play important roles in the global nitrogen cycle by conserving the usable nitrogen in the soil. Here, the electron storage and distribution properties within the pentaheme scaffold of Geobacter lovleyi NrfA were investigated via electron paramagnetic resonance (EPR) spectroscopy coupled with chemical titration experiments. Initially, a chemical reduction method was established to sequentially add electrons to the fully oxidized protein, 1 equiv at a time. The step-by-step reduction of the hemes was then followed using ultraviolet-visible absorption and EPR spectroscopy. EPR spectral simulations were used to elucidate the sequence of heme reduction within the pentaheme scaffold of NrfA and identify the signals of all five hemes in the EPR spectra. Electrochemical experiments ascertain the reduction potentials for each heme, observed in a narrow range from +10 mV (heme 5) to -226 mV (heme 3) (vs the standard hydrogen electrode). On the basis of quantitative analysis and simulation of the EPR data, we demonstrate that hemes 4 and 5 are reduced first (before the active site heme 1) and serve the purpose of an electron storage unit within the protein. To probe the role of the central heme 3, an H108M NrfA variant was generated where the reduction potential of heme 3 is shifted positively (from -226 to +48 mV). The H108M mutation significantly impacts the distribution of electrons within the pentaheme scaffold and the reduction potentials of the hemes, reducing the catalytic activity of the enzyme to 1% compared to that of the wild type. We propose that this is due to heme 3's important role as an electron gateway in the wild-type enzyme.
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Affiliation(s)
- Victor Sosa Alfaro
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Julius Campeciño
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Matthew Tracy
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Sean J Elliott
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Eric L Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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25
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Durand S, Guillier M. Transcriptional and Post-transcriptional Control of the Nitrate Respiration in Bacteria. Front Mol Biosci 2021; 8:667758. [PMID: 34026838 PMCID: PMC8139620 DOI: 10.3389/fmolb.2021.667758] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 03/29/2021] [Indexed: 12/02/2022] Open
Abstract
In oxygen (O2) limiting environments, numerous aerobic bacteria have the ability to shift from aerobic to anaerobic respiration to release energy. This process requires alternative electron acceptor to replace O2 such as nitrate (NO3 -), which has the next best reduction potential after O2. Depending on the organism, nitrate respiration involves different enzymes to convert NO3 - to ammonium (NH4 +) or dinitrogen (N2). The expression of these enzymes is tightly controlled by transcription factors (TFs). More recently, bacterial small regulatory RNAs (sRNAs), which are important regulators of the rapid adaptation of microorganisms to extremely diverse environments, have also been shown to control the expression of genes encoding enzymes or TFs related to nitrate respiration. In turn, these TFs control the synthesis of multiple sRNAs. These results suggest that sRNAs play a central role in the control of these metabolic pathways. Here we review the complex interplay between the transcriptional and the post-transcriptional regulators to efficiently control the respiration on nitrate.
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Affiliation(s)
- Sylvain Durand
- CNRS, UMR 8261, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
| | - Maude Guillier
- CNRS, UMR 8261, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
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26
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Calisto F, Pereira MM. The Ion-Translocating NrfD-Like Subunit of Energy-Transducing Membrane Complexes. Front Chem 2021; 9:663706. [PMID: 33928068 PMCID: PMC8076601 DOI: 10.3389/fchem.2021.663706] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/19/2021] [Indexed: 11/23/2022] Open
Abstract
Several energy-transducing microbial enzymes have their peripheral subunits connected to the membrane through an integral membrane protein, that interacts with quinones but does not have redox cofactors, the so-called NrfD-like subunit. The periplasmic nitrite reductase (NrfABCD) was the first complex recognized to have a membrane subunit with these characteristics and consequently provided the family's name: NrfD. Sequence analyses indicate that NrfD homologs are present in many diverse enzymes, such as polysulfide reductase (PsrABC), respiratory alternative complex III (ACIII), dimethyl sulfoxide (DMSO) reductase (DmsABC), tetrathionate reductase (TtrABC), sulfur reductase complex (SreABC), sulfite dehydrogenase (SoeABC), quinone reductase complex (QrcABCD), nine-heme cytochrome complex (NhcABCD), group-2 [NiFe] hydrogenase (Hyd-2), dissimilatory sulfite-reductase complex (DsrMKJOP), arsenate reductase (ArrC) and multiheme cytochrome c sulfite reductase (MccACD). The molecular structure of ACIII subunit C (ActC) and Psr subunit C (PsrC), NrfD-like subunits, revealed the existence of ion-conducting pathways. We performed thorough primary structural analyses and built structural models of the NrfD-like subunits. We observed that all these subunits are constituted by two structural repeats composed of four-helix bundles, possibly harboring ion-conducting pathways and containing a quinone/quinol binding site. NrfD-like subunits may be the ion-pumping module of several enzymes. Our data impact on the discussion of functional implications of the NrfD-like subunit-containing complexes, namely in their ability to transduce energy.
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Affiliation(s)
- Filipa Calisto
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universdade de Lisboa, Lisboa, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universdade de Lisboa, Lisboa, Portugal
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27
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Zhang D, Liu Y, Han Y, Zhang Y, Jia X, Li W, Li D, Jing L. Nitrate removal from low C/N wastewater at low temperature by immobilized Pseudomonas sp. Y39-6 with versatile nitrate metabolism pathways. BIORESOURCE TECHNOLOGY 2021; 326:124794. [PMID: 33550210 DOI: 10.1016/j.biortech.2021.124794] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 06/12/2023]
Abstract
For solving the challenge in nitrate removal from low C/N wastewater at low temperature, Pseudomonas sp. Y39-6 was isolated and used in nitrate removal. It showed aerobic-heterotrophic denitrification with rate of 1.77 ± 0.31 mg/L·h and unusual aerobic-autotrophic nitrate removal (rate of 0.324 mg/L·h). The aerobic-autotrophic nitrate removal mechanisms were deep investigated by analyzing the nitrate removal process and genomic information. At aerobic-autotrophic condition, the strain Y39-6 could assimilate nitrate to amino acid (NO3- + PHA + CO2 → C5H7O2N) with the carbon source from Polyhydroxyalkanoic acid (PHA) degradation and CO2 fixation. Flagella motivation, swarming activity and extracellular polymeric substances (EPS) production regulated Pseudomonas sp. Y39-6 forming biofilm. Carriers immobilized with Pseudomonas sp. Y39-6 were used in moving bed biofilm reactor (MBBR) and achieved 24.83% nitrate removal at C/N < 1 and 4 °C. Results of this study provided a practical way for nitrogen removal from low C/N wastewater in cold region.
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Affiliation(s)
- Duoying Zhang
- School of Civil Engineering, Heilongjiang University, Harbin 150080, China
| | - Ying Liu
- School of Civil Engineering, Heilongjiang University, Harbin 150080, China
| | - Yaxi Han
- School of Life Science, Heilongjiang University, Harbin 150080, China
| | - Yanlong Zhang
- School of Life Science, Heilongjiang University, Harbin 150080, China.
| | - Xuebin Jia
- School of Civil Engineering, Heilongjiang University, Harbin 150080, China
| | - Weiguang Li
- School of Environment, Harbin Institute of Technology, Harbin 150086, China
| | - Donghui Li
- School of Environment, Harbin Institute of Technology, Harbin 150086, China
| | - Liqiang Jing
- Key Laboratory of Functional Inorganic Material Chemistry, Heilongjiang University, Harbin 150080, China
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28
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Duarte AG, Barbosa ACC, Ferreira D, Manteigas G, Domingos RM, Pereira IAC. Redox loops in anaerobic respiration - The role of the widespread NrfD protein family and associated dimeric redox module. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148416. [PMID: 33753023 DOI: 10.1016/j.bbabio.2021.148416] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 02/25/2021] [Accepted: 03/11/2021] [Indexed: 02/06/2023]
Abstract
In prokaryotes, the proton or sodium motive force required for ATP synthesis is produced by respiratory complexes that present an ion-pumping mechanism or are involved in redox loops performed by membrane proteins that usually have substrate and quinone-binding sites on opposite sides of the membrane. Some respiratory complexes include a dimeric redox module composed of a quinone-interacting membrane protein of the NrfD family and an iron‑sulfur protein of the NrfC family. The QrcABCD complex of sulfate reducers, which includes the QrcCD module homologous to NrfCD, was recently shown to perform electrogenic quinone reduction providing the first conclusive evidence for energy conservation among this family. Similar redox modules are present in multiple respiratory complexes, which can be associated with electroneutral, energy-driven or electrogenic reactions. This work discusses the presence of the NrfCD/PsrBC dimeric redox module in different bioenergetics contexts and its role in prokaryotic energy conservation mechanisms.
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Affiliation(s)
- Américo G Duarte
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
| | - Ana C C Barbosa
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Delfim Ferreira
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Gonçalo Manteigas
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Renato M Domingos
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Inês A C Pereira
- Instituto de Tecnologia Química e Biológica António Xavier/Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
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29
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Evidence for Horizontal and Vertical Transmission of Mtr-Mediated Extracellular Electron Transfer among the Bacteria. mBio 2021; 13:e0290421. [PMID: 35100867 PMCID: PMC8805035 DOI: 10.1128/mbio.02904-21] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Some bacteria and archaea have evolved the means to use extracellular electron donors and acceptors for energy metabolism, a phenomenon broadly known as extracellular electron transfer (EET). One such EET mechanism is the transmembrane electron conduit MtrCAB, which has been shown to transfer electrons derived from metabolic substrates to electron acceptors, like Fe(III) and Mn(IV) oxides, outside the cell. Although most studies of MtrCAB-mediated EET have been conducted in Shewanella oneidensis MR-1, recent investigations in Vibrio and Aeromonas species have revealed that the electron-donating proteins that support MtrCAB in Shewanella are not as representative as previously thought. This begs the question of how widespread the capacity for MtrCAB-mediated EET is, the changes it has accrued in different lineages, and where these lineages persist today. Here, we employed a phylogenetic and comparative genomics approach to identify the MtrCAB system across all domains of life. We found mtrCAB in the genomes of numerous diverse Bacteria from a wide range of environments, and the patterns therein strongly suggest that mtrCAB was distributed through both horizontal and subsequent vertical transmission, and with some cases indicating downstream modular diversification of both its core and accessory components. Our data point to an emerging evolutionary story about metal-oxidizing and -reducing metabolism, demonstrates that this capacity for EET has broad relevance to a diversity of taxa and the biogeochemical cycles they drive, and lays the foundation for further studies to shed light on how this mechanism may have coevolved with Earth's redox landscape. IMPORTANCE While many metabolisms make use of soluble, cell-permeable substrates like oxygen or hydrogen, there are other substrates, like iron or manganese, that cannot be brought into the cell. Some bacteria and archaea have evolved the means to directly "plug in" to such environmental electron reservoirs in a process known as extracellular electron transfer (EET), making them powerful agents of biogeochemical change and promising vehicles for bioremediation and alternative energy. Yet the diversity, distribution, and evolution of EET mechanisms are poorly constrained. Here, we present findings showing that the genes encoding one such EET system (mtrCAB) are present in a broad diversity of bacteria found in a wide range of environments, emphasizing the ubiquity and potential impact of EET in our biosphere. Our results suggest that these genes have been disseminated largely through horizontal transfer, and the changes they have accrued in these lineages potentially reflect adaptations to changing environments.
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30
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Calisto F, Sousa FM, Sena FV, Refojo PN, Pereira MM. Mechanisms of Energy Transduction by Charge Translocating Membrane Proteins. Chem Rev 2021; 121:1804-1844. [PMID: 33398986 DOI: 10.1021/acs.chemrev.0c00830] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Life relies on the constant exchange of different forms of energy, i.e., on energy transduction. Therefore, organisms have evolved in a way to be able to harvest the energy made available by external sources (such as light or chemical compounds) and convert these into biological useable energy forms, such as the transmembrane difference of electrochemical potential (Δμ̃). Membrane proteins contribute to the establishment of Δμ̃ by coupling exergonic catalytic reactions to the translocation of charges (electrons/ions) across the membrane. Irrespectively of the energy source and consequent type of reaction, all charge-translocating proteins follow two molecular coupling mechanisms: direct- or indirect-coupling, depending on whether the translocated charge is involved in the driving reaction. In this review, we explore these two coupling mechanisms by thoroughly examining the different types of charge-translocating membrane proteins. For each protein, we analyze the respective reaction thermodynamics, electron transfer/catalytic processes, charge-translocating pathways, and ion/substrate stoichiometries.
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Affiliation(s)
- Filipa Calisto
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipe M Sousa
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipa V Sena
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Patricia N Refojo
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
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31
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Enebe MC, Babalola OO. Soil fertilization affects the abundance and distribution of carbon and nitrogen cycling genes in the maize rhizosphere. AMB Express 2021; 11:24. [PMID: 33555438 PMCID: PMC7870749 DOI: 10.1186/s13568-021-01182-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 01/11/2021] [Indexed: 12/11/2022] Open
Abstract
Soil microbes perform important functions in nitrogen and carbon cycling in the biosphere. Microbial communities in the rhizosphere enhance plants' health and promote nutrient turnover and cycling in the soil. In this study, we evaluated the effects of soil fertilization with organic and inorganic fertilizers on the abundances and distribution of carbon and nitrogen cycling genes within the rhizosphere of maize plants. Our result showed that maize plants through rhizosphere effects selected and enriched the same functional genes glnA, gltB, gudB involved in nitrogen cycle as do high compost and low inorganic fertilizer treatments. This observation was significantly different from those of high doses of inorganic fertilizer and low compost manure treated soil. Only alpha amylase encoding genes were selectively enriched by low compost and high inorganic fertilized soil. The other treatments only selected xynB (in Cp8), lacZ (Cp4), bglA, pldB, trpA (N2), uidA (N1) and glgC, vanA (Cn0) carbon cycling genes in the rhizosphere of maize. Also Actinomycetales are selected by high compost, low inorganic fertilizer and control. The control was without any fertilization and the soil was planted with maize. Bacillales are also promoted by low compost and high inorganic fertilizer. This indicated that only microbes capable of tolerating the stress of high dose of inorganic fertilizer will thrive under such condition. Therefore, soil fertilization lowers nitrogen gas emission as seen with the high abundance of nitrogen assimilation genes or microbial anabolic genes, but increases carbon dioxide evolution in the agricultural soil by promoting the abundance of catabolic genes involve in carbon cycling.
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32
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Nie WB, Ding J, Xie GJ, Yang L, Peng L, Tan X, Liu BF, Xing DF, Yuan Z, Ren NQ. Anaerobic Oxidation of Methane Coupled with Dissimilatory Nitrate Reduction to Ammonium Fuels Anaerobic Ammonium Oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:1197-1208. [PMID: 33185425 DOI: 10.1021/acs.est.0c02664] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) is critical for mitigating methane emission and returning reactive nitrogen to the atmosphere. The genomes of n-DAMO archaea show that they have the potential to couple anaerobic oxidation of methane to dissimilatory nitrate reduction to ammonium (DNRA). However, physiological details of DNRA for n-DAMO archaea were not reported yet. This work demonstrated n-DAMO archaea coupling the anaerobic oxidation of methane to DNRA, which fueled Anammox in a methane-fed membrane biofilm reactor with nitrate as only electron acceptor. Microelectrode analysis revealed that ammonium accumulated where nitrite built up in the biofilm. Ammonium production and significant upregulation of gene expression for DNRA were detected in suspended n-DAMO culture with nitrite exposure, indicating that nitrite triggered DNRA by n-DAMO archaea. 15N-labeling batch experiments revealed that n-DAMO archaea produced ammonium from nitrate rather than from external nitrite. Localized gradients of nitrite produced by n-DAMO archaea in biofilms induced ammonium production via the DNRA process, which promoted nitrite consumption by Anammox bacteria and in turn helped n-DAMO archaea resist stress from nitrite. As biofilms predominate in various ecosystems, anaerobic oxidation of methane coupled with DNRA could be an important link between the global carbon and nitrogen cycles that should be investigated in future research.
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Affiliation(s)
- Wen-Bo Nie
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73, Huanghe Road, Nangang, Harbin 150090, Heilongjiang, China
| | - Jie Ding
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73, Huanghe Road, Nangang, Harbin 150090, Heilongjiang, China
| | - Guo-Jun Xie
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73, Huanghe Road, Nangang, Harbin 150090, Heilongjiang, China
| | - Lu Yang
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551, Singapore
| | - Lai Peng
- School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China
| | - Xin Tan
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73, Huanghe Road, Nangang, Harbin 150090, Heilongjiang, China
| | - Bing-Feng Liu
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73, Huanghe Road, Nangang, Harbin 150090, Heilongjiang, China
| | - De-Feng Xing
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73, Huanghe Road, Nangang, Harbin 150090, Heilongjiang, China
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Nan-Qi Ren
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73, Huanghe Road, Nangang, Harbin 150090, Heilongjiang, China
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33
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Peterson BD, McDaniel EA, Schmidt AG, Lepak RF, Janssen SE, Tran PQ, Marick RA, Ogorek JM, DeWild JF, Krabbenhoft DP, McMahon KD. Mercury Methylation Genes Identified across Diverse Anaerobic Microbial Guilds in a Eutrophic Sulfate-Enriched Lake. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:15840-15851. [PMID: 33228362 PMCID: PMC9741811 DOI: 10.1021/acs.est.0c05435] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Mercury (Hg) methylation is a microbially mediated process that converts inorganic Hg into bioaccumulative, neurotoxic methylmercury (MeHg). The metabolic activity of methylating organisms is highly dependent on biogeochemical conditions, which subsequently influences MeHg production. However, our understanding of the ecophysiology of methylators in natural ecosystems is still limited. Here, we identified potential locations of MeHg production in the anoxic, sulfidic hypolimnion of a freshwater lake. At these sites, we used shotgun metagenomics to characterize microorganisms with the Hg-methylation gene hgcA. Putative methylators were dominated by hgcA sequences divergent from those in well-studied, confirmed methylators. Using genome-resolved metagenomics, we identified organisms with hgcA (hgcA+) within the Bacteroidetes and the recently described Kiritimatiellaeota phyla. We identified hgcA+ genomes derived from sulfate-reducing bacteria, but these accounted for only 22% of hgcA+ genome coverage. The most abundant hgcA+ genomes were from fermenters, accounting for over half of the hgcA gene coverage. Many of these organisms also mediate hydrolysis of polysaccharides, likely from cyanobacterial blooms. This work highlights the distribution of the Hg-methylation genes across microbial metabolic guilds and indicate that primary degradation of polysaccharides and fermentation may play an important but unrecognized role in MeHg production in the anoxic hypolimnion of freshwater lakes.
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Affiliation(s)
- Benjamin D. Peterson
- Environmental Science & Technology Program, University of Wisconsin - Madison, 660 N. Park Street, Madison, WI 53706, USA
- Corresponding author:
| | - Elizabeth A. McDaniel
- Department of Bacteriology, University of Wisconsin - Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Anna G. Schmidt
- Department of Bacteriology, University of Wisconsin - Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Ryan F. Lepak
- Environmental Science & Technology Program, University of Wisconsin - Madison, 660 N. Park Street, Madison, WI 53706, USA
- U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
- U.S. Environmental Protection Agency Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, MN 55804, USA
| | - Sarah E. Janssen
- U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
| | - Patricia Q. Tran
- Department of Bacteriology, University of Wisconsin - Madison, 1550 Linden Drive, Madison, WI 53706, USA
- Department of Integrative Biology, University of Wisconsin - Madison, 250 N. Mills St.Madison, WI 53706, USA
| | - Robert A. Marick
- Department of Biochemistry, University of Wisconsin - Madison, 433 Babcock Drive, Madison, WI 53706, USA
| | - Jacob M. Ogorek
- U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
| | - John F. DeWild
- U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
| | - David P. Krabbenhoft
- U.S. Geological Survey, Upper Midwest Water Science Center, Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
| | - Katherine D. McMahon
- Department of Bacteriology, University of Wisconsin - Madison, 1550 Linden Drive, Madison, WI 53706, USA
- Department of Civil and Environmental Engineering, University of Wisconsin – Madison, 1415 Engineering Drive, Madison WI 53706, USA
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34
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Andoralov V, Shleev S, Dergousova N, Kulikova O, Popov V, Tikhonova T. Octaheme nitrite reductase: The mechanism of intramolecular electron transfer and kinetics of nitrite bioelectroreduction. Bioelectrochemistry 2020; 138:107699. [PMID: 33221569 DOI: 10.1016/j.bioelechem.2020.107699] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 11/24/2022]
Abstract
Detailed impedance and voltammetric studies of hexameric octaheme nitrite reductase immobilized on carbon-based nanomaterials, specifically nanotubes and nanoparticles, were performed. Well-pronounced bioelectrocatalytic reduction of nitrite on enzyme-modified electrodes was obtained. Analysis of the impedance data indicated the absence of long-lived intermediates involved in the nitrite reduction. Cyclic voltammograms of biomodified electrodes had a bi-sigmoidal shape, which pointed to the presence of two enzyme orientations on carbon supports. The maximum (limiting) catalytic currents were determined and, by applying the correction by the mixed kinetics equation, the Tafel dependences were plotted for each catalytic wave/each enzyme orientation. Finally, two schemes for the rate-limiting processes during bioelectrocatalysis were proposed, viz. for low- and high-potential orientations.
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Affiliation(s)
- Victor Andoralov
- Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden
| | - Sergey Shleev
- Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden; Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Natalia Dergousova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Olga Kulikova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Vladimir Popov
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; Kurchatov NBIC Centre, National Research Centre "Kurchatov Institute", 123182 Moscow, Russia
| | - Tamara Tikhonova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia.
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35
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Huang YY, Liang MH, Zhao S, Chen SM, Liu JS, Liu DM, Lu YZ. Isolation, expression, and biochemical characterization: nitrite reductase from Bacillus cereus LJ01. RSC Adv 2020; 10:37871-37882. [PMID: 35515171 PMCID: PMC9057199 DOI: 10.1039/d0ra06129h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/23/2020] [Indexed: 11/24/2022] Open
Abstract
Biological remediation of toxic oxygen-containing anions such as nitrate that are common in the environment is of great significance. Therefore, it is necessary to understand the specific role of nitrate and nitrite reductase in the bioremediation process. Bacillus cereus LJ01, which was isolated from traditional Chinese soybean paste, effectively degraded nitrite (such as NaNO2) at 0–15 mmol L−1 in LB medium. Moreover, the nitrite-degrading active substance (ASDN) was isolated and purified from B. cereus LJ01. The nitrite-degrading activity of nitrite reductase (named LJ01-NiR) was 4004.89 U mg−1. The gene encoding the assimilation of nitrite reductase in B. cereus LJ01 was cloned and overexpressed in E. coli. The purified recombinant LJ01-NiR has a wide range of activities under temperature (20–60 °C), pH (6.5–8.0) and metal ions (Fe3+, Fe2+, Cu2+, Mn2+, and Al3+). Kinetic parameters of LJ01-NiR, including the values of Km and Vmax were 1.38 mM and 2.00 μmol g−1 min−1, respectively. The results showed that LJ01-NiR could degrade nitrite with or without an electron donor. In addition, sequence analysis revealed that LJ01-NiR was a ferredoxin-dependent nitrite reductase given the presence of conserved [Fe4–S4] cluster and heme-binding domain. The nitrite ion binds to the LJ01-NiR active site by forming three hydrogen bonds with the residues ASN72, ALA133 and ASN140. Due to its high nitrite-degrading activity, LJ01-NiR could potentially be used for environmental pollution treatment. Biological remediation of toxic oxygen-containing anions such as nitrite in the environment is of great significance. Bacillus cereus LJ01 showed the activity of degradation for nitrite. the enzyme NiR from LJ01 can degrade the nitrite in vitro.![]()
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Affiliation(s)
- Yan-Yan Huang
- School of Food Science and Engineering, South China University of Technology 381 Wushan Road Guangzhou Guangdong 510640 People's Republic of China
| | - Ming-Hua Liang
- School of Food Science and Engineering, South China University of Technology 381 Wushan Road Guangzhou Guangdong 510640 People's Republic of China
| | - Shan Zhao
- School of Food Science and Engineering, South China University of Technology 381 Wushan Road Guangzhou Guangdong 510640 People's Republic of China
| | - Si-Min Chen
- School of Food Science and Engineering, South China University of Technology 381 Wushan Road Guangzhou Guangdong 510640 People's Republic of China
| | - Jin-Song Liu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences 190 Kaiyuan Avenue, Science Park, Huangpu District Guangzhou 510530 People's Republic of China
| | - Dong-Mei Liu
- School of Food Science and Engineering, South China University of Technology 381 Wushan Road Guangzhou Guangdong 510640 People's Republic of China
| | - Yong-Zhi Lu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences 190 Kaiyuan Avenue, Science Park, Huangpu District Guangzhou 510530 People's Republic of China
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Pandey CB, Kumar U, Kaviraj M, Minick KJ, Mishra AK, Singh JS. DNRA: A short-circuit in biological N-cycling to conserve nitrogen in terrestrial ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 738:139710. [PMID: 32544704 DOI: 10.1016/j.scitotenv.2020.139710] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/21/2020] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
This paper reviews dissimilatory nitrate reduction to ammonium (DNRA) in soils - a newly appreciated pathway of nitrogen (N) cycling in the terrestrial ecosystems. The reduction of NO3- occurs in two steps; in the first step, NO3- is reduced to NO2-; and in the second, unlike denitrification, NO2- is reduced to NH4+ without intermediates. There are two sets of NO3-/NO2- reductase enzymes, i.e., Nap/Nrf and Nar/Nir; the former occurs on the periplasmic-membrane and energy conservation is respiratory via electron-transport-chain, whereas the latter is cytoplasmic and energy conservation is both respiratory and fermentative (Nir, substrate-phosphorylation). Since, Nir catalyzes both assimilatory- and dissimilatory-nitrate reduction, the nrfA gene, which transcribes the NrfA protein, is treated as a molecular-marker of DNRA; and a high nrfA/nosZ (N2O-reductase) ratio favours DNRA. Recently, several crystal structures of NrfA have been presumed to producee N2O as a byproduct of DNRA via the NO (nitric-oxide) pathway. Meta-analyses of about 200 publications have revealed that DNRA is regulated by oxidation state of soils and sediments, carbon (C)/N and NO2-/NO3- ratio, and concentrations of ferrous iron (Fe2+) and sulfide (S2-). Under low-redox conditions, a high C/NO3- ratio selects for DNRA while a low ratio selects for denitrification. When the proportion of both C and NO3- are equal, the NO2-/NO3- ratio modulates partitioning of NO3-, and a high NO2-/NO3- ratio favours DNRA. A high S2-/NO3- ratio also promotes DNRA in coastal-ecosystems and saline sediments. Soil pH, temperature, and fine soil particles are other factors known to influence DNRA. Since, DNRA reduces NO3- to NH4+, it is essential for protecting NO3- from leaching and gaseous (N2O) losses and enriches soils with readily available NH4+-N to primary producers and heterotrophic microorganisms. Therefore, DNRA may be treated as a tool to reduce ground-water NO3- pollution, enhance soil health and improve environmental quality.
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Affiliation(s)
- C B Pandey
- ICAR-Central Arid Zone Research Institute, Jodhpur 342003, Rajasthan, India.
| | - Upendra Kumar
- ICAR-National Rice Research Institute, Cuttack 753006, Odisha, India.
| | - Megha Kaviraj
- ICAR-National Rice Research Institute, Cuttack 753006, Odisha, India
| | - K J Minick
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA
| | - A K Mishra
- International Rice Research Institute, New Delhi 110012, India
| | - J S Singh
- Ecosystem Analysis Lab, Centre of Advanced Study in Botany, Banaras Hindu University (BHU), Varanasi 221005, India
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37
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Kang X, Cui Y, Shen T, Yan M, Tu W, Shoaib M, Xiang Q, Zhao K, Gu Y, Chen Q, Li S, Liang Y, Ma M, Zou L, Yu X. Changes of root microbial populations of natively grown plants during natural attenuation of V-Ti magnetite tailings. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 201:110816. [PMID: 32521370 DOI: 10.1016/j.ecoenv.2020.110816] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 05/28/2023]
Abstract
Mine tailings contain dangerously high levels of toxic metals which pose a constant threat to local ecosystems. Few naturally grown native plants can colonize tailings site and the existence of their root-associated microbial populations is poorly understood. The objective of this study was to give further insights into the interactions between native plants and their microbiota during natural attenuation of abandoned V-Ti magnetite mine tailings. In the present work, we first examined the native plants' potential for phytoremediation using plant/soil analytical methods and then investigated the root microbial communities and their inferred functions using 16 S rRNA-based metagenomics. It was found that in V-Ti magnetite mine tailings the two dominant plants Bothriochloa ischaemum and Typha angustifolia were able to increase available nitrogen in the rhizosphere soil by 23.3% and 53.7% respectively. The translocation factors (TF) for both plants indicated that B. ischaemum was able to accumulate Pb (TF = 1.212), while T. angustifolia was an accumulator of Mn (TF = 2.502). The microbial community structure was more complex in the soil associated with T. angustifolia than with B. ischaemum. The presence of both plants significantly reduced the population of Acinetobacter. Specifically, B. ischaemum enriched Massilia, Opitutus and Hydrogenophaga species while T. angustifolia significantly increased rhizobia species. Multivariate analyses revealed that among all tested soil variables Fe and total organic carbon (TOC) could be the key factors in shaping the microbial structure. The putative functional analysis indicated that soil sample of B. ischaemum was abundant with nitrate/nitrite reduction-related functions while that of T. angustifolia was rich in nitrogen fixing functions. The results indicate that these native plants host a diverse range of soil microbes, whose community structure can be shaped by plant types and soil variables. It is also possible that these plants can be used to improve soil nitrogen content and serve as bioaccumulators for Pb or Mn for phytoremediation purposes.
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Affiliation(s)
- Xia Kang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China; Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Yongliang Cui
- Sichuan Provincial Academy of Natural Resource and Sciences, Chengdu, 610015, China
| | - Tian Shen
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Min Yan
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Weiguo Tu
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Muhammad Shoaib
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Quanju Xiang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Ke Zhao
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yunfu Gu
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Qiang Chen
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Shuangcheng Li
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yueyang Liang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Menggen Ma
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Likou Zou
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xiumei Yu
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China.
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Campeciño J, Lagishetty S, Wawrzak Z, Sosa Alfaro V, Lehnert N, Reguera G, Hu J, Hegg EL. Cytochrome c nitrite reductase from the bacterium Geobacter lovleyi represents a new NrfA subclass. J Biol Chem 2020; 295:11455-11465. [PMID: 32518164 PMCID: PMC7450111 DOI: 10.1074/jbc.ra120.013981] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/07/2020] [Indexed: 01/07/2023] Open
Abstract
Cytochrome c nitrite reductase (NrfA) catalyzes the reduction of nitrite to ammonium in the dissimilatory nitrate reduction to ammonium (DNRA) pathway, a process that competes with denitrification, conserves nitrogen, and minimizes nutrient loss in soils. The environmental bacterium Geobacter lovleyi has recently been recognized as a key driver of DNRA in nature, but its enzymatic pathway is still uncharacterized. To address this limitation, here we overexpressed, purified, and characterized G. lovleyi NrfA. We observed that the enzyme crystallizes as a dimer but remains monomeric in solution. Importantly, its crystal structure at 2.55-Å resolution revealed the presence of an arginine residue in the region otherwise occupied by calcium in canonical NrfA enzymes. The presence of EDTA did not affect the activity of G. lovleyi NrfA, and site-directed mutagenesis of this arginine reduced enzymatic activity to <3% of the WT levels. Phylogenetic analysis revealed four separate emergences of Arg-containing NrfA enzymes. Thus, the Ca2+-independent, Arg-containing NrfA from G. lovleyi represents a new subclass of cytochrome c nitrite reductase. Most genera from the exclusive clades of Arg-containing NrfA proteins are also represented in clades containing Ca2+-dependent enzymes, suggesting convergent evolution.
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Affiliation(s)
- Julius Campeciño
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Satyanarayana Lagishetty
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Zdzislaw Wawrzak
- Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, Illinois, USA
| | - Victor Sosa Alfaro
- Department of Chemistry and Biophysics, The University of Michigan, Ann Arbor, Michigan, USA
| | - Nicolai Lehnert
- Department of Chemistry and Biophysics, The University of Michigan, Ann Arbor, Michigan, USA
| | - Gemma Reguera
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Jian Hu
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA,Department of Chemistry, Michigan State University, East Lansing, Michigan, USA
| | - Eric L. Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA,For correspondence: Eric L. Hegg,
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Adyasari D, Hassenrück C, Montiel D, Dimova N. Microbial community composition across a coastal hydrological system affected by submarine groundwater discharge (SGD). PLoS One 2020; 15:e0235235. [PMID: 32598345 PMCID: PMC7323985 DOI: 10.1371/journal.pone.0235235] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/10/2020] [Indexed: 11/18/2022] Open
Abstract
Mobile Bay, the fourth largest estuary in the USA located in the northern Gulf of Mexico, is known for extreme hypoxia in the water column during dry season caused by NH4+-rich and anoxic submarine groundwater discharge (SGD). Nutrient dynamics in the coastal ecosystem point to potentially elevated microbial activities; however, little is known about microbial community composition and their functional roles in this area. In this study, we investigated microbial community composition, distribution, and metabolic prediction along the coastal hydrological compartment of Mobile Bay using 16S rRNA gene sequencing. We collected microbial samples from surface (river and bay water) and subsurface water (groundwater and coastal pore water from two SGD sites with peat and sandy lithology, respectively). Salinity was identified as the primary factor affecting the distribution of microbial communities across surface water samples, while DON and PO43- were the major predictor of community shift within subsurface water samples. Higher microbial diversity was found in coastal pore water in comparison to surface water samples. Gammaproteobacteria, Bacteroidia, and Oxyphotobacteria dominated the bacterial community. Among the archaea, methanogens were prevalent in the peat-dominated SGD site, while the sandy SGD site was characterized by a higher proportion of ammonia-oxidizing archaea. Cyanobium PCC-6307 and unclassified Thermodesulfovibrionia were identified as dominant taxa strongly associated with trends in environmental parameters in surface and subsurface samples, respectively. Microbial communities found in the groundwater and peat layer consisted of taxa known for denitrification and dissimilatory nitrate reduction to ammonium (DNRA). This finding suggested that microbial communities might also play a significant role in mediating nitrogen transformation in the SGD flow path and in affecting the chemical composition of SGD discharging to the water column. Given the ecological importance of microorganisms, further studies at higher taxonomic and functional resolution are needed to accurately predict chemical biotransformation processes along the coastal hydrological continuum, which influence water quality and environmental condition in Mobile Bay.
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Affiliation(s)
- Dini Adyasari
- Department of Biogeochemistry and Geology, Leibniz Centre for Tropical Marine Research, Bremen, Germany
| | - Christiane Hassenrück
- Department of Biogeochemistry and Geology, Leibniz Centre for Tropical Marine Research, Bremen, Germany
| | - Daniel Montiel
- Department of Geological Sciences, Coastal Hydrogeology Laboratory, University of Alabama, Alabama, AL, United States of America
- Geosyntec Consultants, Clearwater, FL, United States of America
| | - Natasha Dimova
- Department of Geological Sciences, Coastal Hydrogeology Laboratory, University of Alabama, Alabama, AL, United States of America
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40
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Quistad SD, Doulcier G, Rainey PB. Experimental manipulation of selfish genetic elements links genes to microbial community function. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190681. [PMID: 32200751 PMCID: PMC7133536 DOI: 10.1098/rstb.2019.0681] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Microbial communities underpin the Earth's biological and geochemical processes, but their complexity hampers understanding. Motivated by the challenge of diversity and the need to forge ways of capturing dynamical behaviour connecting genes to function, biologically independent experimental communities comprising hundreds of microbial genera were established from garden compost and propagated on nitrogen-limited minimal medium with cellulose (paper) as sole carbon source. After 1 year of bi-weekly transfer, communities retained hundreds of genera. To connect genes to function, we used a simple experimental manipulation that involved the periodic collection of selfish genetic elements (SGEs) from separate communities, followed by pooling and redistribution across communities. The treatment was predicted to promote amplification and dissemination of SGEs and thus horizontal gene transfer. Confirmation came from comparative metagenomics, which showed the substantive movement of ecologically significant genes whose dynamic across space and time could be followed. Enrichment of genes implicated in nitrogen metabolism, and particularly ammonification, prompted biochemical assays that revealed a measurable impact on community function. Our simple experimental strategy offers a conceptually new approach for unravelling dynamical processes affecting microbial community function. This article is part of the theme issue ‘Conceptual challenges in microbial community ecology’.
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Affiliation(s)
- Steven D Quistad
- Laboratoire de Génétique de l'Evolution, Chemistry, Biology and Innovation (CBI) UMR8231, ESPCI Paris, CNRS, PSL Research University, 10 rue Vauquelin, Paris, France
| | - Guilhem Doulcier
- Laboratoire de Génétique de l'Evolution, Chemistry, Biology and Innovation (CBI) UMR8231, ESPCI Paris, CNRS, PSL Research University, 10 rue Vauquelin, Paris, France
| | - Paul B Rainey
- Laboratoire de Génétique de l'Evolution, Chemistry, Biology and Innovation (CBI) UMR8231, ESPCI Paris, CNRS, PSL Research University, 10 rue Vauquelin, Paris, France.,Department of Microbial Population Biology, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
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41
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Comparison of Community and Function of Dissimilatory Nitrate Reduction to Ammonium (DNRA) Bacteria in Chinese Shallow Lakes with Different Eutrophication Degrees. WATER 2020. [DOI: 10.3390/w12010174] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dissimilatory nitrate reduction to ammonium (DNRA) plays an important role in controlling nitrogen (N) loading in lake ecosystems. However, studies on the linkage between DNRA bacterial community structure and lake eutrophication remain unclear. We examined the community and abundance of DNRA bacteria at six basins of four shallow lakes with different degrees of eutrophication in China. Measurements of the different forms of N and phosphorus (P) in the water column and interstitial water as well as total organic carbon (TOC) and sulfide in the sediments in summer (July 2016) were performed. The nutritional status of Lake Chaohu was more serious than that of the lakes in Wuhan, including Lake Qingling, Lake Houguan, and Lake Zhiyin by comparing geochemical and physical parameters. We found a higher abundance of the nrfA gene, which is a function gene of DNRA bacteria in sediments with higher contents of TOC and sulfide. Moreover, nitrate was a significant factor influencing the DNRA bacterial community structure. A significant difference of the DNRA bacterial community structure between Lake Chaohu and the lakes in Wuhan was discovered. Furthermore, DNRA bacterial abundance and community positively correlated with NH4+ and Chl a concentrations in Lake Chaohu, in which a percent abundance of dominant populations varied along eutrophication gradients. Overall, the abundance and community structure of the DNRA bacteria might be important regulators of eutrophication and cyanobacteria bloom in Lake Chaohu.
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42
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Assessment of Heterotrophic Nitrification Capacity in Bacillus spp. and its Potential Application in the Removal of Nitrogen from Aquaculture Water. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2019. [DOI: 10.22207/jpam.13.4.02] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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43
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Aigle A, Bonin P, Fernandez-Nunez N, Loriod B, Guasco S, Bergon A, Armougom F, Iobbi-Nivol C, Imbert J, Michotey V. The nature of the electron acceptor (MnIV/NO3) triggers the differential expression of genes associated with stress and ammonium limitation responses in Shewanella algae C6G3. FEMS Microbiol Lett 2019; 365:4939474. [PMID: 29566166 DOI: 10.1093/femsle/fny068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/15/2018] [Indexed: 01/05/2023] Open
Abstract
Shewanella algae C6G3 can dissimilatively reduce nitrate into ammonium and manganese oxide (MnIV) into MnII. It has the unusual ability to anaerobically produce nitrite from ammonium in the presence of MnIV. To gain insight into their metabolic capabilities, global mRNA expression patterns were investigated by RNA-seq and qRT-PCR in cells growing with lactate and ammonium as carbon and nitrogen sources, and with either MnIV or nitrate as electron acceptors. Genes exhibiting higher expression levels in the presence of MnIV belonged to functional categories of carbohydrate, coenzyme, lipid metabolisms and inorganic ion transport. The comparative transcriptomic pattern between MnIV and NO3 revealed that the strain presented an ammonium limitation status with MnIV, despite the presence of a non-limiting concentration of ammonium under both culture conditions. In addition, in the presence of MnIV, ntrB/nrtC regulators, ammonium channel, nitrogen regulatory protein P-II, glutamine synthetase and asparagine synthetase glutamine-dependent genes were over-represented. Under the nitrate condition, the expression of genes involved in the synthesis of several amino acids was increased. Finally, the expression level of genes associated with the general stress response was also amplified in both conditions and among them, katE, a putative catalase/peroxidase present on several Shewanella genomes, was highly expressed with a median value relatively higher in the MnIV condition.
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Affiliation(s)
- Axel Aigle
- Aix Marseille Univ, Univ Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, Marseille, France
| | - Patricia Bonin
- Aix Marseille Univ, Univ Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, Marseille, France
| | | | - Béatrice Loriod
- UMR_S 1090, TGML/TAGC, Aix-Marseille Université, Marseille F-13009, France
| | - Sophie Guasco
- Aix Marseille Univ, Univ Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, Marseille, France
| | - Aurélie Bergon
- UMR_S 1090, TGML/TAGC, Aix-Marseille Université, Marseille F-13009, France
| | - Fabrice Armougom
- Aix Marseille Univ, Univ Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, Marseille, France
| | - Chantal Iobbi-Nivol
- Aix-Marseille Université, CNRS, BIP Bioénergétique et Ingénierie des Protéines UMR 7281, 13402, Marseille, France
| | - Jean Imbert
- UMR_S 1090, TGML/TAGC, Aix-Marseille Université, Marseille F-13009, France
| | - Valérie Michotey
- Aix Marseille Univ, Univ Toulon, CNRS, IRD, MIO UM 110, Mediterranean Institute of Oceanography, Marseille, France
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Gnandt D, Koslowski T. Long-range electron-electron interaction and charge transfer in protein complexes: a numerical approach. Phys Chem Chem Phys 2019; 21:18595-18604. [PMID: 31414082 DOI: 10.1039/c9cp03141c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
With application to the nitrite reductase hexameric protein complex of Desulfovibrio vulgaris, NrfH2A4, we suggest a strategy to compute the energy landscape of electron transfer in large systems of biochemical interest. For small complexes, the energy of all electronic configurations can be scanned completely on the level of a numerical solution of the Poisson-Boltzmann equation. In contrast, larger systems have to be treated using a pair approximation, which is verified here. Effective Coulomb interactions between neighbouring sites of excess electron localization may become as large as 200 meV, and they depend in a nontrivial manner on the intersite distance. We discuss the implications of strong Coulomb interactions on the thermodynamics and kinetics of charging and decharging a protein complex. Finally, we turn to the effect of embedding the system into a biomembrane.
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Affiliation(s)
- David Gnandt
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 23a, 79104 Freiburg im Breisgau, Germany.
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How Thermophilic Gram-Positive Organisms Perform Extracellular Electron Transfer: Characterization of the Cell Surface Terminal Reductase OcwA. mBio 2019; 10:mBio.01210-19. [PMID: 31431546 PMCID: PMC6703420 DOI: 10.1128/mbio.01210-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Thermophilic Gram-positive organisms were recently shown to be a promising class of organisms to be used in bioelectrochemical systems for the production of electrical energy. These organisms present a thick peptidoglycan layer that was thought to preclude them to perform extracellular electron transfer (i.e., exchange catabolic electrons with solid electron acceptors outside the cell). In this paper, we describe the structure and functional mechanisms of the multiheme cytochrome OcwA, the terminal reductase of the Gram-positive bacterium Thermincola potens JR found at the cell surface of this organism. The results presented here show that this protein can take the role of a respiratory “Swiss Army knife,” allowing this organism to grow in environments with soluble and insoluble substrates. Moreover, it is shown that it is unrelated to terminal reductases found at the cell surface of other electroactive organisms. Instead, OcwA is similar to terminal reductases of soluble electron acceptors. Our data reveal that terminal oxidoreductases of soluble and insoluble substrates are evolutionarily related, providing novel insights into the evolutionary pathway of multiheme cytochromes. Extracellular electron transfer is the key process underpinning the development of bioelectrochemical systems for the production of energy or added-value compounds. Thermincola potens JR is a promising Gram-positive bacterium to be used in these systems because it is thermophilic. In this paper, we describe the structural and functional properties of the nonaheme cytochrome OcwA, which is the terminal reductase of this organism. The structure of OcwA, determined at 2.2-Å resolution, shows that the overall fold and organization of the hemes are not related to other metal reductases and instead are similar to those of multiheme cytochromes involved in the biogeochemical cycles of nitrogen and sulfur. We show that, in addition to solid electron acceptors, OcwA can also reduce soluble electron shuttles and oxyanions. These data reveal that OcwA can work as a multipurpose respiratory enzyme allowing this organism to grow in environments with rapidly changing availability of terminal electron acceptors without the need for transcriptional regulation and protein synthesis.
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46
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Ali M, Stein N, Mao Y, Shahid S, Schmidt M, Bennett B, Pacheco AA. Trapping of a Putative Intermediate in the Cytochrome c Nitrite Reductase (ccNiR)-Catalyzed Reduction of Nitrite: Implications for the ccNiR Reaction Mechanism. J Am Chem Soc 2019; 141:13358-13371. [DOI: 10.1021/jacs.9b03036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mahbbat Ali
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Natalia Stein
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Yingxi Mao
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Shahid Shahid
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Marius Schmidt
- Department of Physics, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Brian Bennett
- Department of Physics, Marquette University, Milwaukee, Wisconsin 53233, United States
| | - A. Andrew Pacheco
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
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The Porphyromonas gingivalis Hybrid Cluster Protein Hcp Is Required for Growth with Nitrite and Survival with Host Cells. Infect Immun 2019; 87:IAI.00572-18. [PMID: 30670550 DOI: 10.1128/iai.00572-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 01/11/2019] [Indexed: 12/13/2022] Open
Abstract
Although the periodontal pathogen Porphyromonas gingivalis must withstand high levels of nitrosative stress while in the oral cavity, the mechanisms of nitrosative stress defense are not well understood in this organism. Previously we showed that the transcriptional regulator HcpR plays a significant role in defense, and here we further defined its regulon. Our study shows that hcp (PG0893), a putative nitric oxide (NO) reductase, is the only gene significantly upregulated in response to nitrite (NO2) and that this regulation is dependent on HcpR. An isogenic mutant deficient in hcp is not able to grow with 200 μM nitrite, demonstrating that the sensitivity of the HcpR mutant is mediated through Hcp. We further define the molecular mechanisms of HcpR interaction with the hcp promoter through mutational analysis of the inverted repeat present within the promoter. Although other putative nitrosative stress protection mechanisms present on the nrfAH operon are also found in the P. gingivalis genome, we show that their gene products play no role in growth of the bacterium with nitrite. As growth of the hcp-deficient strain was also significantly diminished in the presence of a nitric oxide-producing compound, S-nitrosoglutathione (GSNO), Hcp appears to be the primary means by which P. gingivalis responds to NO2 --based stress. Finally, we show that Hcp is required for survival with host cells but that loss of Hcp has no effect on association and entry of P. gingivalis into human oral keratinocytes.
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Lan W, Yang C. Ruminal methane production: Associated microorganisms and the potential of applying hydrogen-utilizing bacteria for mitigation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 654:1270-1283. [PMID: 30841400 DOI: 10.1016/j.scitotenv.2018.11.180] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/12/2018] [Accepted: 11/12/2018] [Indexed: 05/16/2023]
Abstract
Methane emission from ruminants not only causes serious environmental problems, but also represents a significant source of energy loss to animals. The increasing demand for sustainable animal production is driving researchers to explore proper strategies to mitigate ruminal methanogenesis. Since hydrogen is the primary substrate of ruminal methanogenesis, hydrogen metabolism and its associated microbiome in the rumen may closely relate to low- and high-methane phenotypes. Using candidate microbes that can compete with methanogens and redirect hydrogen away from methanogenesis as ruminal methane mitigants are promising avenues for methane mitigation, which can both prevent the adverse effects deriving from chemical additives such as toxicity and resistance, and increase the retention of feed energy. This review describes the ruminal microbial ecosystem and its association with methane production, as well as the effects of interspecies hydrogen transfer on methanogenesis. It provides a scientific perspective on using bacteria that are involved in hydrogen utilization as ruminal modifiers to decrease methanogenesis. This information will be helpful in better understanding the key role of ruminal microbiomes and their relationship with methane production and, therefore, will form the basis of valuable and eco-friendly methane mitigation methods while improving animal productivity.
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Affiliation(s)
- Wei Lan
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China; MoE Key Laboratory of Molecular Animal Nutrition, China
| | - Chunlei Yang
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China; MoE Key Laboratory of Molecular Animal Nutrition, China.
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Duarte AG, Catarino T, White GF, Lousa D, Neukirchen S, Soares CM, Sousa FL, Clarke TA, Pereira IAC. An electrogenic redox loop in sulfate reduction reveals a likely widespread mechanism of energy conservation. Nat Commun 2018; 9:5448. [PMID: 30575735 PMCID: PMC6303296 DOI: 10.1038/s41467-018-07839-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/27/2018] [Indexed: 02/02/2023] Open
Abstract
The bioenergetics of anaerobic metabolism frequently relies on redox loops performed by membrane complexes with substrate- and quinone-binding sites on opposite sides of the membrane. However, in sulfate respiration (a key process in the biogeochemical sulfur cycle), the substrate- and quinone-binding sites of the QrcABCD complex are periplasmic, and their role in energy conservation has not been elucidated. Here we show that the QrcABCD complex of Desulfovibrio vulgaris is electrogenic, as protons and electrons required for quinone reduction are extracted from opposite sides of the membrane, with a H+/e− ratio of 1. Although the complex does not act as a H+-pump, QrcD may include a conserved proton channel leading from the N-side to the P-side menaquinone pocket. Our work provides evidence of how energy is conserved during dissimilatory sulfate reduction, and suggests mechanisms behind the functions of related bacterial respiratory complexes in other bioenergetic contexts. The bacterial complex QrcABCD plays a key role in the bioenergetics of sulfate respiration. Here, Duarte et al. show that this complex is electrogenic, with protons and electrons required for quinone reduction being extracted from opposite sides of the membrane.
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Affiliation(s)
- Américo G Duarte
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Teresa Catarino
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.,Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Gaye F White
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Diana Lousa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Sinje Neukirchen
- Division of Archaea Biology and Ecogenomics, Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14 UZA I, 1090, Vienna, Austria
| | - Cláudio M Soares
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Filipa L Sousa
- Division of Archaea Biology and Ecogenomics, Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14 UZA I, 1090, Vienna, Austria
| | - Thomas A Clarke
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Inês A C Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.
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Divergent Nrf Family Proteins and MtrCAB Homologs Facilitate Extracellular Electron Transfer in Aeromonas hydrophila. Appl Environ Microbiol 2018; 84:AEM.02134-18. [PMID: 30266730 DOI: 10.1128/aem.02134-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 09/26/2018] [Indexed: 01/05/2023] Open
Abstract
Extracellular electron transfer (EET) is a strategy for respiration in which electrons generated from metabolism are moved outside the cell to a terminal electron acceptor, such as iron or manganese oxide. EET has primarily been studied in two model systems, Shewanella oneidensis and Geobacter sulfurreducens Metal reduction has also been reported in numerous microorganisms, including Aeromonas spp., which are ubiquitous Gammaproteobacteria found in aquatic ecosystems, with some species capable of pathogenesis in humans and fish. Genomic comparisons of Aeromonas spp. revealed a potential outer membrane conduit homologous to S. oneidensis MtrCAB. While the ability to respire metals and mineral oxides is not widespread in the genus Aeromonas, 90% of the sequenced Aeromonas hydrophila isolates contain MtrCAB homologs. A. hydrophila ATCC 7966 mutants lacking mtrA are unable to reduce metals. Expression of A. hydrophila mtrCAB in an S. oneidensis mutant lacking homologous components restored metal reduction. Although the outer membrane conduits for metal reduction were similar, homologs of the S. oneidensis inner membrane and periplasmic EET components CymA, FccA, and CctA were not found in A. hydrophila We characterized a cluster of genes predicted to encode components related to a formate-dependent nitrite reductase (NrfBCD), here named NetBCD (for Nrf-like electron transfer), and a predicted diheme periplasmic cytochrome, PdsA (periplasmic diheme shuttle). We present genetic evidence that proteins encoded by this cluster facilitate electron transfer from the cytoplasmic membrane across the periplasm to the MtrCAB conduit and function independently from an authentic NrfABCD system. A. hydrophila mutants lacking pdsA and netBCD were unable to reduce metals, while heterologous expression of these genes could restore metal reduction in an S. oneidensis mutant background. EET may therefore allow A. hydrophila and other species of Aeromonas to persist and thrive in iron- or manganese-rich oxygen-limited environments.IMPORTANCE Metal-reducing microorganisms are used for electricity production, bioremediation of toxic compounds, wastewater treatment, and production of valuable compounds. Despite numerous microorganisms being reported to reduce metals, the molecular mechanism has primarily been studied in two model systems, Shewanella oneidensis and Geobacter sulfurreducens We have characterized the mechanism of extracellular electron transfer in Aeromonas hydrophila, which uses the well-studied Shewanella system, MtrCAB, to move electrons across the outer membrane; however, most Aeromonas spp. appear to use a novel mechanism to transfer electrons from the inner membrane through the periplasm and to the outer membrane. The conserved use of MtrCAB in Shewanella spp. and Aeromonas spp. for metal reduction and conserved genomic architecture of metal reduction genes in Aeromonas spp. may serve as genomic markers for identifying metal-reducing microorganisms from genomic or transcriptomic sequencing. Understanding the variety of pathways used to reduce metals can allow for optimization and more efficient design of microorganisms used for practical applications.
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