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Egenolf K, Schöne J, Conrad J, Braunberger C, Beifuß U, Arango J, Rasche F. Root exudate fingerprint of Brachiaria humidicola reveals vanillin as a novel and effective nitrification inhibitor. Front Mol Biosci 2023; 10:1192043. [PMID: 38116382 PMCID: PMC10728723 DOI: 10.3389/fmolb.2023.1192043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 10/23/2023] [Indexed: 12/21/2023] Open
Abstract
Introduction: Biological Nitrification Inhibition (BNI) is defined as the plant-mediated control of soil nitrification via the release of nitrification inhibitors. BNI of Brachiaria humidicola (syn. Urochloa humidicola) has been mainly attributed to root-exuded fusicoccane-type diterpenes, e.g., 3-epi-brachialactone. We hypothesized, however, that BNI of B. humidicola is caused by an assemblage of bioactive secondary metabolites. Methods: B. humidicola root exudates were collected hydroponically, and metabolites were isolated by semi-preparative HPLC. Chemical structures were elucidated by HRMS as well as 1D and 2D NMR spectroscopy. Nitrification inhibiting potential of isolated metabolites was evaluated by a Nitrosomonas europaea based bioassay. Results and discussion: Besides previously described brachialactone isomers and derivatives, five phenol and cinnamic acid derivatives were identified in the root exudates of B. humidicola: 2-hydroxy-3-(hydroxymethyl)benzaldehyde, vanillin, umbelliferone and both trans- and cis-2,6-dimethoxycinnamic acid. Notably, vanillin revealed a substantially higher nitrification inhibiting activity than 3-epi-brachialactone (ED50 ∼ 12.5 μg·ml-1, ED80 ∼ 20 μg·ml-1), identifying this phenolic aldehyde as novel nitrification inhibitor (NI). Furthermore, vanillin exudation rates were in the same range as 3-epi-brachialactone (1-4 μg·h-1·g-1 root DM), suggesting a substantial contribution to the overall inhibitory activity of B. humidicola root exudates. In relation to the verification of the encountered effects within soils and considering the exclusion of any detrimental impact on the soil microbiome, the biosynthetic pathway of vanillin via the precursor phenylalanine and the intermediates p-coumaric acid/ferulic acid (precursors of further phenolic NI) might constitute a promising BNI breeding target. This applies not only to Brachiaria spp., but also to crops in general, owing to the highly conserved nature of these metabolites.
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Affiliation(s)
- Konrad Egenolf
- Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Stuttgart, Germany
- Tropical Forages Program, The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Jochen Schöne
- Institute of Phytomedicine, University of Hohenheim, Stuttgart, Germany
| | - Jürgen Conrad
- Institute of Chemistry, University of Hohenheim, Stuttgart, Germany
| | | | - Uwe Beifuß
- Institute of Chemistry, University of Hohenheim, Stuttgart, Germany
| | - Jacobo Arango
- Tropical Forages Program, The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Frank Rasche
- Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Stuttgart, Germany
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Kolovou M, Panagiotou D, Süße L, Loiseleur O, Williams S, Karpouzas DG, Papadopoulou ES. Assessing the activity of different plant-derived molecules and potential biological nitrification inhibitors on a range of soil ammonia- and nitrite-oxidizing strains. Appl Environ Microbiol 2023; 89:e0138023. [PMID: 37916825 PMCID: PMC10686072 DOI: 10.1128/aem.01380-23] [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: 08/09/2023] [Accepted: 09/26/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Synthetic nitrification inhibitors are routinely used with nitrogen fertilizers to reduce nitrogen losses from agroecosystems, despite having drawbacks like poor efficiency, cost, and entry into the food chain. Plant-derived BNIs constitute a more environmentally conducive alternative. Knowledge on the activity of BNIs to soil nitrifiers is largely based on bioassays with a single Nitrosomonas europaea strain which does not constitute a dominant member of the community of ammonia-oxidizing microorganisms (AOM) in soil. We determined the activity of several plant-derived molecules reported as having activity, including the recently discovered maize-isolated BNI, zeanone, and its natural analog, 2-methoxy-1,4-naphthoquinone, on a range of ecologically relevant AOM and one nitrite-oxidizing bacterial culture, expanding our knowledge on the intrinsic inhibition potential of BNIs toward AOM and highlighting the necessity for a deeper understanding of the effect of BNIs on the overall soil microbiome integrity before their further use in agricultural settings.
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Affiliation(s)
- Maria Kolovou
- Department of Environmental Sciences, Laboratory of Environmental Microbiology, University of Thessaly, Larissa, Greece
| | - Dimitra Panagiotou
- Department of Biochemistry and Biotechnology, Laboratory of Plant and Environmental Biotechnology, University of Thessaly, Larissa, Greece
| | - Lars Süße
- Syngenta Crop Protection AG, Basel, Switzerland
| | | | | | - Dimitrios G. Karpouzas
- Department of Biochemistry and Biotechnology, Laboratory of Plant and Environmental Biotechnology, University of Thessaly, Larissa, Greece
| | - Evangelia S. Papadopoulou
- Department of Environmental Sciences, Laboratory of Environmental Microbiology, University of Thessaly, Larissa, Greece
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Mizukami-Murata S, Takanashi H, Sawai A, Suzuki Y, Tsushima I, Yamashita H, Goto Y, Toda M. Characteristics of compounds with strong or weak nitrification inhibition in sewage. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:1437. [PMID: 37940732 DOI: 10.1007/s10661-023-12074-z] [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: 04/18/2023] [Accepted: 10/30/2023] [Indexed: 11/10/2023]
Abstract
To clarify the characteristics of compounds with strong or weak nitrification inhibition in sewage, 64 organic compounds including compounds registered in Pollutant Release and Transfer Register (PRTR) were evaluated in terms of their chemical structures and molecular weights. Nineteen compounds showed strong nitrification inhibition by testing with Nitrosomonas europaea. Compounds with thioamide structures had the lowest median value of EC50 (0.017 mg/L), followed by those with alkyne structures (0.121 mg/L), chlorophenol structures (0.300 mg/L), and then azole structures (0.365 mg/L). In contrast, 33 of the 64 compounds showed weak nitrification inhibition at a concentration of 10 mg/L, 27 of which were categorized into three main groups: long-chain alcohol structures, alkyne structures with a phenyl group, and aromatic structures. Most compounds with strong nitrification inhibition had a low molecular weight (MW) from 50 to 200. Meanwhile, the proportion of compounds with weak nitrification inhibition tended to be greater with increasing MW and such compounds were predominant at higher molecular weights above 300. The correlations of results derived from tests of nitrification inhibition based on ISO 9509 and N. europaea showed that 24 out of 30 compounds provided results that were highly correlated between these tests (R = 0.85), while 4 compounds with chlorophenol structures and 2 compounds with alkyne structures showed weaker inhibition rates in the ISO 9509 test than in the N. europaea test. Our results indicate that the magnitude of nitrification inhibition depends on MW in addition to the chemical structure, which is helpful in the search for the cause of nitrification inhibition in wastewater treatment plants.
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Affiliation(s)
- Satomi Mizukami-Murata
- Water Quality Team, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, Ibaraki, 305-8516, Japan.
| | - Hirokazu Takanashi
- Chemistry and Biotechnology Program, Department of Engineering, Graduate School of Science, and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima, 890-0065, Japan
| | - Atsushi Sawai
- IDEA Consultants, Inc., 3-15-1 Komazawa, Setagaya-Ku, Tokyo, 154-8585, Japan
| | - Yuji Suzuki
- Department of Civil Engineering, Gifu University, C-214, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Ikuo Tsushima
- Water Quality Team, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, Ibaraki, 305-8516, Japan
| | - Hiromasa Yamashita
- Water Quality Team, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, Ibaraki, 305-8516, Japan
| | - Yasushi Goto
- IDEA Consultants, Inc., 3-15-1 Komazawa, Setagaya-Ku, Tokyo, 154-8585, Japan
| | - Misa Toda
- IDEA Consultants, Inc., 3-15-1 Komazawa, Setagaya-Ku, Tokyo, 154-8585, Japan
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Canisares LP, Rosolem CA, Momesso L, Crusciol CAC, Villegas DM, Arango J, Ritz K, Cantarella H. Maize-Brachiaria intercropping: A strategy to supply recycled N to maize and reduce soil N 2O emissions? AGRICULTURE, ECOSYSTEMS & ENVIRONMENT 2021; 319:107491. [PMID: 34602686 PMCID: PMC8363933 DOI: 10.1016/j.agee.2021.107491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/04/2021] [Accepted: 05/10/2021] [Indexed: 06/13/2023]
Abstract
Nitrogen use in agriculture directly impacts food security, global warming, and environmental degradation. Forage grasses intercropped with maize produce feed for animals and or mulch for no-till systems. Forage grasses may exude nitrification inhibitors. It was hypothesized that brachiaria intercropping increases N recycling and maize grain yield and reduces nitrous oxide (N2O) emissions from soil under maize cropping. A field experiment was set up in December 2016 to test three cropping system (maize monocropped, maize intercropped with Brachiaria brizantha or with B. humidicola) and two N rates (0 or 150 kg ha-1). The grasses were sown with maize, but B. humidicola did not germinate well in the first year. B. brizantha developed slowly during the maize cycle because of shading but expanded after maize was harvested. The experiment was repeated in 2017/2018 when B. humidicola was replanted. N2O and carbon dioxide (CO2) emissions, maize grain yield and N content were measured during the two seasons. After the first maize harvest, the above- and below-ground biomass, C and N content of B. brizantha grown during fall-winter, and the biological nitrification inhibition potential of B. brizantha were evaluated. Maize yield responded to N fertilization (5.1 vs. 9.8 t ha-1) but not to brachiaria intercropping. B. brizantha recycled approximately 140 kg N ha-1 and left 12 t dry matter ha-1 for the second maize crop. However, the 2017/18 maize yields were not affected by the N recycled by B. brizantha, whereas N2O emissions were higher in the plots with brachiaria, suggesting that part of the recycled N was released too early after desiccation. Brachiarias showed no evidence of causing nitrification inhibition. The strategy of intercropping brachiarias did not increase maize yield, although it added C and recycled N in the system.
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Affiliation(s)
| | - Ciro Antonio Rosolem
- São Paulo State University, College of Agricultural Sciences, Botucatu, São Paulo 18603-970, Brazil
| | - Letusa Momesso
- São Paulo State University, College of Agricultural Sciences, Botucatu, São Paulo 18603-970, Brazil
| | | | | | - Jacobo Arango
- International Center for Tropical Agriculture (CIAT), Cali 763537, Colombia
| | - Karl Ritz
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicester LE12 5RD, UK
| | - Heitor Cantarella
- Agronomic Institute of Campinas, Campinas, São Paulo 13012-970, Brazil
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Wang X, Bai J, Xie T, Wang W, Zhang G, Yin S, Wang D. Effects of biological nitrification inhibitors on nitrogen use efficiency and greenhouse gas emissions in agricultural soils: A review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 220:112338. [PMID: 34015632 DOI: 10.1016/j.ecoenv.2021.112338] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/26/2021] [Accepted: 05/10/2021] [Indexed: 05/27/2023]
Abstract
To maintain and increase crop yields, large amounts of nitrogen fertilizers have been applied to farmland. However, the nitrogen use efficiency (NUE) of chemical fertilizer remains very low, which may lead to serious environmental problems, including nitrate pollution, air quality degradation and greenhouse gas (GHG) emissions. Nitrification inhibitors can alleviate nitrogen loss by inhibiting nitrification; thus, biological nitrification inhibition by plants has gradually attracted increasing attention due to its low cost and environmental friendliness. Research progress on BNI is reviewed in this article, including the source, mechanisms, influencing factors and application of BNIs. In addition, the impact of BNI on agriculture and GHG emissions is summarized from the perspective of agricultural production and environmental protection, and the key future research prospects of BNIs are also noted.
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Affiliation(s)
- Xin Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Junhong Bai
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Tian Xie
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Wei Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Guangliang Zhang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Shuo Yin
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Dawei Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
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Ji G, Xu L, Lyu Q, Liu Y, Gong X, Li X, Yan Z. Poly-γ-glutamic acid production by simultaneous saccharification and fermentation using corn straw and its fertilizer synergistic effect evaluation. Bioprocess Biosyst Eng 2021; 44:2181-2191. [PMID: 34086133 DOI: 10.1007/s00449-021-02593-9] [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: 03/02/2021] [Accepted: 05/25/2021] [Indexed: 10/21/2022]
Abstract
Agricultural wastes rich in lignocellulosic biomass have been used in the production of poly-γ-glutamic acid (γ-PGA) through separate hydrolysis and fermentation (SHF), but this process is complicated and generates a lot of wastes. In order to find a simpler and greener way to produce γ-PGA using agricultural wastes, this study attempted to establish simultaneous saccharification and fermentation (SSF) with citric acid-pretreated corn straw. The possibility of Bacillus amyloliquefaciens JX-6 using corn straw as substrate to synthesize γ-PGA was validated, and the results showed that increasing the proportion of glucose in the substrate could improve the γ-PGA yield. Based on these preliminary results, the corn straw was pretreated using citric acid. Then, the liquid fraction (xylan-rich) was used for cultivation of seed culture, and the solid fraction (glucan-rich) was used as the substrate for SSF. In a 10-L fermenter, the maximum cumulative γ-PGA concentration in batch and fed-batch SSF were 5.08 ± 0.78 g/L and 10.78 ± 0.32 g/L, respectively. Moreover, the product from SSF without γ-PGA extraction was used as a fertilizer synergist, increasing the yield of pepper by 13.46% (P < 0.05). Our study greatly simplified the production steps of γ-PGA, and each step achieved zero emission as far as possible. The SSF process for γ-PGA production provided a simple and green way for lignocellulose biorefinery and sustainable cultivation in agriculture.
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Affiliation(s)
- Gaosheng Ji
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lishan Xu
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, People's Republic of China
| | - Qingyang Lyu
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, People's Republic of China
| | - Yang Liu
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, People's Republic of China
| | - Xuefeng Gong
- Institute of Horticulture, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, China
| | - Xudong Li
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, People's Republic of China
| | - Zhiying Yan
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, People's Republic of China.
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The Sorghum bicolor Root Exudate Sorgoleone Shapes Bacterial Communities and Delays Network Formation. mSystems 2021; 6:6/2/e00749-20. [PMID: 33727394 PMCID: PMC8546980 DOI: 10.1128/msystems.00749-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Primary and secondary metabolites exuded from roots are key drivers of root-soil microbe interactions that contribute to the structure and function of microbial communities. Studies with model plants have begun to reveal the complex interactions between root exudates and soil microbes, but little is known about the influence of specialized exudates from crop plants. The aims of this work were to understand whether sorgoleone, a unique lipophilic secondary benzoquinone exuded only from the root hairs of sorghum, influences belowground microbial community structure in the field, to assess the effect of purified sorgoleone on the cultured bacteria from field soils, and to determine whether sorgoleone inhibits nitrification under field conditions. Studies were conducted comparing wild-type sorghum and lines with genetically reduced sorgoleone exudation. In the soil near roots and rhizosphere, sorgoleone influenced microbial community structure as measured by β-diversity and network analysis. Under greenhouse conditions, the soil nitrogen content was an important factor in determining the impacts of sorgoleone. Sorgoleone delayed the formation of the bacterial and archaeal networks early in plant development and only inhibited nitrification at specific sampling times under field conditions. Sorgoleone was also shown to both inhibit and promote cultured bacterial isolate growth in laboratory tests. These findings provide new insights into the role of secondary metabolites in shaping the composition and function of the sorghum root-associated bacterial microbiomes. Understanding how root exudates modify soil microbiomes may potentially unlock an important tool for enhancing crop sustainability and yield in our changing environment.IMPORTANCE Plant roots exude a complex mixture of metabolites into the rhizosphere. Primary and secondary metabolites exuded from roots are key drivers of root-soil microbe interactions that contribute to the structure and function of microbial communities in agricultural and natural ecosystems. Previous work on plant root exudates and their influence on soil microbes has mainly been restricted to model plant species. Plant are a diverse group of organisms and produce a wide array of different secondary metabolites. Therefore, it is important to go beyond studies of model plants to fully understand the diverse repertoire of root exudates in crop plant species that feed human populations. Extending studies to a wider array of root exudates will provide a more comprehensive understanding of how the roots of important food crops interact with highly diverse soil microbial communities. This will provide information that could lead to tailoring root exudates for the development of more beneficial plant-soil microbe interactions that will benefit agroecosystem productivity.
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Nardi P, Laanbroek HJ, Nicol GW, Renella G, Cardinale M, Pietramellara G, Weckwerth W, Trinchera A, Ghatak A, Nannipieri P. Biological nitrification inhibition in the rhizosphere: determining interactions and impact on microbially mediated processes and potential applications. FEMS Microbiol Rev 2021; 44:874-908. [PMID: 32785584 DOI: 10.1093/femsre/fuaa037] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 08/10/2020] [Indexed: 12/11/2022] Open
Abstract
Nitrification is the microbial conversion of reduced forms of nitrogen (N) to nitrate (NO3-), and in fertilized soils it can lead to substantial N losses via NO3- leaching or nitrous oxide (N2O) production. To limit such problems, synthetic nitrification inhibitors have been applied but their performance differs between soils. In recent years, there has been an increasing interest in the occurrence of biological nitrification inhibition (BNI), a natural phenomenon according to which certain plants can inhibit nitrification through the release of active compounds in root exudates. Here, we synthesize the current state of research but also unravel knowledge gaps in the field. The nitrification process is discussed considering recent discoveries in genomics, biochemistry and ecology of nitrifiers. Secondly, we focus on the 'where' and 'how' of BNI. The N transformations and their interconnections as they occur in, and are affected by, the rhizosphere, are also discussed. The NH4+ and NO3- retention pathways alternative to BNI are reviewed as well. We also provide hypotheses on how plant compounds with putative BNI ability can reach their targets inside the cell and inhibit ammonia oxidation. Finally, we discuss a set of techniques that can be successfully applied to solve unresearched questions in BNI studies.
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Affiliation(s)
- Pierfrancesco Nardi
- Consiglio per la ricerca e l'analisi dell'economia agraria - Research Centre for Agriculture and Environment (CREA-AA), Via della Navicella 2-4, Rome 00184, Italy
| | - Hendrikus J Laanbroek
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands; Ecology and Biodiversity Group, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Graeme W Nicol
- Laboratoire Ampère, École Centrale de Lyon, Université de Lyon, Ecully, 69134, France
| | - Giancarlo Renella
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Viale dell'Università 16, 35020 Legnaro, Italy
| | - Massimiliano Cardinale
- Department of Biological and Environmental Sciences and Technologies - DiSTeBA, University of Salento, Centro Ecotekne - via Provinciale Lecce-Monteroni, I-73100, Lecce, Italy
| | - Giacomo Pietramellara
- Department of Agriculture, Food, Environment and Forestry, University of Firenze, P.le delle Cascine 28, Firenze 50144, Italy
| | - Wolfram Weckwerth
- Molecular Systems Biology (MOSYS), Department of Functional and Evolutionary Ecology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria; Vienna Metabolomics Center (VIME), University of Vienna, Althanstrasse 14, Vienna, 1090, Austria
| | - Alessandra Trinchera
- Consiglio per la ricerca e l'analisi dell'economia agraria - Research Centre for Agriculture and Environment (CREA-AA), Via della Navicella 2-4, Rome 00184, Italy
| | - Arindam Ghatak
- Molecular Systems Biology (MOSYS), Department of Functional and Evolutionary Ecology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria
| | - Paolo Nannipieri
- Department of Agriculture, Food, Environment and Forestry, University of Firenze, P.le delle Cascine 28, Firenze 50144, Italy
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Zappi D, Coronado E, Soljan V, Basile G, Varani G, Turemis M, Giardi MT. A microbial sensor platform based on bacterial bioluminescence (luxAB) and green fluorescent protein (gfp) reporters for in situ monitoring of toxicity of wastewater nitrification process dynamics. Talanta 2021; 221:121438. [DOI: 10.1016/j.talanta.2020.121438] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 07/13/2020] [Accepted: 07/19/2020] [Indexed: 10/23/2022]
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Egenolf K, Conrad J, Schöne J, Braunberger C, Beifuß U, Walker F, Nuñez J, Arango J, Karwat H, Cadisch G, Neumann G, Rasche F. Brachialactone isomers and derivatives of Brachiaria humidicola reveal contrasting nitrification inhibiting activity. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 154:491-497. [PMID: 32663650 DOI: 10.1016/j.plaphy.2020.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/29/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
Biological Nitrification Inhibition (BNI) of Brachiaria humidicola has been mainly attributed to the root-exuded fusicoccane-type diterpene brachialactone. We hypothesized, however, that according to the high diversity of fusicoccanes described for plants and microorganisms, BNI of B. humidicola is caused by an assemblage of bioactive fusicoccanes. B. humidicola root exudates were collected hydroponically and compounds isolated by semi-preparative HPLC. Chemical structures were revealed by spectroscopic techniques, including HRMS as well as 1D and 2D NMR. Nitrification inhibiting (NI) potential of isolated compounds was evaluated by a Nitrosomonas europaea based bioassay. Besides the previously described brachialactone (1), root exudates contained 3-epi-brachialactone (2), the C3-epimer of 1 (m/z 334), as well as 16-hydroxy-3-epi-brachialactone (3) with an additional hydroxyl group at C16 (m/z 350) and 3,18-epoxy-9-hydroxy-4,7-seco-brachialactone (4), which is a ring opened brachialactone derivative with a 3,18 epoxide ring and a hydroxyl group at C9 (m/z 332). The 3-epi-brachialactone (2) showed highest NI activity (ED50 ~ 20 μg mL-1, ED80 ~ 40 μg mL-1), followed by compound 4 with intermediate (ED50 ~ 40 μg mL-1), brachialactone (1) with low and compound 3 without activity. In coherence with previous reports on fusicoccanes, stereochemistry at C3 was of high relevance for the biological activity (NI potential) of brachialactones.
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Affiliation(s)
- Konrad Egenolf
- Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, 70593, Stuttgart, Germany; The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT), Km 17 Recta Cali-Palmira, A.A, 6713, Cali, Colombia
| | - Jürgen Conrad
- Institute of Chemistry, University of Hohenheim, 70593, Stuttgart, Germany
| | - Jochen Schöne
- Institute of Phytomedicine, University of Hohenheim, 70593, Stuttgart, Germany
| | | | - Uwe Beifuß
- Institute of Chemistry, University of Hohenheim, 70593, Stuttgart, Germany
| | - Frank Walker
- Institute of Phytomedicine, University of Hohenheim, 70593, Stuttgart, Germany
| | - Jonathan Nuñez
- The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT), Km 17 Recta Cali-Palmira, A.A, 6713, Cali, Colombia
| | - Jacobo Arango
- The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT), Km 17 Recta Cali-Palmira, A.A, 6713, Cali, Colombia
| | - Hannes Karwat
- Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, 70593, Stuttgart, Germany; The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT), Km 17 Recta Cali-Palmira, A.A, 6713, Cali, Colombia
| | - Georg Cadisch
- Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, 70593, Stuttgart, Germany
| | - Günter Neumann
- Institute of Crop Sciences, University of Hohenheim, 70593, Stuttgart, Germany
| | - Frank Rasche
- Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, 70593, Stuttgart, Germany.
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Villegas D, Arevalo A, Nuñez J, Mazabel J, Subbarao G, Rao I, De Vega J, Arango J. Biological Nitrification Inhibition (BNI): Phenotyping of a Core Germplasm Collection of the Tropical Forage Grass Megathyrsus maximus Under Greenhouse Conditions. FRONTIERS IN PLANT SCIENCE 2020; 11:820. [PMID: 32595688 PMCID: PMC7304326 DOI: 10.3389/fpls.2020.00820] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/22/2020] [Indexed: 05/31/2023]
Abstract
Modern intensively managed pastures that receive large external nitrogen (N) inputs account for high N losses in form of nitrate (NO3 -) leaching and emissions of the potent greenhouse gas nitrous oxide (N2O). The natural plant capacity to shape the soil N cycle through exudation of organic compounds can be exploited to favor N retention without affecting productivity. In this study, we estimated the relationship between biological nitrification inhibition (BNI), N2O emissions and plant productivity for 119 germplasm accessions of Guineagrass (Megathyrsus maximus), an important tropical forage crop for livestock production. This relation was tested in a greenhouse experiment measuring BNI as (i) rates of soil nitrification; (ii) abundance of ammonia-oxidizing bacteria (AOB) and archaea (AOA); and (iii) the capacity of root tissue extracts to inhibit nitrification in vitro. We then measured N2O emissions, aboveground biomass and forage nutrition quality parameters. Reductions on nitrification activity ranging between 30 and 70% were found across the germplasm collection of M. maximus. Accessions with low nitrification rates showed a lower abundance of AOB as well as a reduction in N2O emissions compared to accessions of high nitrification rates. The BNI capacity was not correlated to N uptake of plants, suggesting that there may be intraspecific variation in the exploitation of different N sources in this grass species. A group of accessions (cluster) with the most desirable agronomic and environmental traits among the collection was identified for further field validation. These results provide evidence of the ability of M. maximus to suppress soil nitrification and N2O emissions and their relationship with productivity and forage quality, pointing a way to develop N conservative improved forage grasses for tropical livestock production.
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Affiliation(s)
- Daniel Villegas
- International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Ashly Arevalo
- International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Jonathan Nuñez
- International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Johanna Mazabel
- International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Guntur Subbarao
- Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Japan
| | - Idupulapati Rao
- International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Jose De Vega
- Earlham Institute, Norwich Research Park, Norwich, United Kingdom
| | - Jacobo Arango
- International Center for Tropical Agriculture (CIAT), Cali, Colombia
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12
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Wendeborn S. Chemie, Biologie und Regulierung der Nitrifikation von Ammonium im Boden. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201903014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sebastian Wendeborn
- Fachhochschule Nordwestschweiz FHNWHochschule für Life SciencesInstitut für Chemie und Bioanalytik Hofackerstrasse 30 CH-4132 Muttenz Schweiz
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13
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Modrzyński JJ, Christensen JH, Brandt KK. Evaluation of dimethyl sulfoxide (DMSO) as a co-solvent for toxicity testing of hydrophobic organic compounds. ECOTOXICOLOGY (LONDON, ENGLAND) 2019; 28:1136-1141. [PMID: 31559559 DOI: 10.1007/s10646-019-02107-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
Toxicity testing of hydrophobic compounds with low aqueous solubility remains challenging. Dimethyl sulfoxide (DMSO) is widely used as a co-solvent for toxicity testing of hydrophobic chemicals, but it may modulate chemical toxicity patterns. In this study, we critically evaluated the suitability of DMSO as a co-solvent for toxicity testing of hydrophobic organic compounds in aqueous solutions. As the toxicity measure, we used growth inhibition of a natural bacterial community, and the test toxicants included phenol, BTEX (benzene, toluene, ethylbenzene and xylene) and transformation products of polycyclic aromatic hydrocarbons (PAHs). We found that dose-response curves for phenol were unaffected by DMSO concentrations up to 10% (v/v) and that DMSO (5% v/v) did not affect the degree of bacterial growth inhibition for any of the other test compounds in short-term experiments (3.5 h). By contrast, marked co-solvent effects of DMSO were observed in the long-term assay (25 and 27 h). We therefore conclude that DMSO has excellent co-solvent properties for short-term (≤3.5 h) toxicity testing of sparingly water-soluble compounds and its application provides a simple, inexpensive approach for screening of various environmentally relevant hydrophobic chemicals. Importantly, the use of DMSO allows for generation of full dose-responses that may otherwise not be attained.
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Affiliation(s)
- Jakub J Modrzyński
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350, Copenhagen, Denmark
| | - Jan H Christensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark
| | - Kristian K Brandt
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.
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14
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Wendeborn S. The Chemistry, Biology, and Modulation of Ammonium Nitrification in Soil. Angew Chem Int Ed Engl 2019; 59:2182-2202. [PMID: 31116902 DOI: 10.1002/anie.201903014] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/15/2019] [Indexed: 11/11/2022]
Abstract
Approximately two percent of the world's energy is consumed in the production of ammonia from hydrogen and nitrogen gas. Ammonia is used as a fertilizer ingredient for agriculture and distributed in the environment on an enormous scale to promote crop growth in intensive farming. Only 30-50 % of the nitrogen applied is assimilated by crop plants; the remaining 50-70 % goes into biological processes such as nitrification by microbial metabolism in the soil. This leads to an imbalance in the global nitrogen cycle and higher nitrous oxide emissions (a potent and significant greenhouse gas) as well as contamination of ground and surface waters by nitrate from the nitrogen-fertilized farmland. This Review gives a critical overview of the current knowledge of soil microbes involved in the chemistry of ammonia nitrification, the structures and mechanisms of the enzymes involved, and phytochemicals capable of inhibiting ammonia nitrification.
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Affiliation(s)
- Sebastian Wendeborn
- University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Institute for Chemistry and Bioanalytics, Hofackerstrasse 30, CH-4132, Muttenz, Switzerland
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15
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Yu H, Qu F, Zhang X, Wang P, Li G, Liang H. Effect of quorum quenching on biofouling and ammonia removal in membrane bioreactor under stressful conditions. CHEMOSPHERE 2018; 199:114-121. [PMID: 29433024 DOI: 10.1016/j.chemosphere.2018.02.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/22/2018] [Accepted: 02/04/2018] [Indexed: 06/08/2023]
Abstract
Quorum quenching (QQ) has been used to control biofouling in membrane bioreactors (MBRs), but the effect of QQ on the performance of MBR has not been systematically studied. This study investigated the effect of QQ on ammonia removal in MBR especially in some stressful conditions. The results showed that membrane fouling was effectively alleviated by QQ in all conditions. For the short HRT (3.94 h), the ammonia removal in QQ-MBR was fluctuating. In the presence of nitrification inhibitors (acetonitrile and allylthiourea) or at low temperature (10 °C), QQ induced much more significant suppression on nitrification in batch test and MBR. The number of the ammonia oxidizing bacteria (AOB) was not decreasing in these situations, which indicated that QQ only suppressed the activity of AOB. In all, comprehensive considerations should be taken into account when applying a QS tuning strategy to a bioreactor.
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Affiliation(s)
- Huarong Yu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Fangshu Qu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China.
| | - Xiaolei Zhang
- Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea
| | - Peng Wang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Guibai Li
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, 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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16
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Vilajeliu-Pons A, Koch C, Balaguer MD, Colprim J, Harnisch F, Puig S. Microbial electricity driven anoxic ammonium removal. WATER RESEARCH 2018; 130:168-175. [PMID: 29220717 DOI: 10.1016/j.watres.2017.11.059] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/07/2017] [Accepted: 11/27/2017] [Indexed: 05/03/2023]
Abstract
Removal of nitrogen, mainly in form of ammonium (NH4+), in wastewater treatment plants (WWTPs) is a highly energy demanding process, mainly due to aeration. It causes costs of about half a million Euros per year in an average European WWTP. Alternative, more economical technologies for the removal of nitrogen compounds from wastewater are required. This study proves the complete anoxic conversion of ammonium (NH4+) to dinitrogen gas (N2) in continuously operated bioelectrochemical systems at the litre-scale. The removal rate is comparable to conventional WWTPs with 35 ± 10 g N m-3 d-1 with low accumulation of NO2-, NO3-, N2O. In contrast to classical aerobic nitrification, the energy consumption is considerable lower (1.16 ± 0.21 kWh kg-1 N, being more than 35 times less than for the conventional wastewater treatment). Biotic and abiotic control experiments confirmed that the anoxic nitrification was an electrochemical biological process mainly performed by Nitrosomonas with hydroxylamine as the main substrate (mid-point potential, Eox = +0.67 ± 0.08 V vs. SHE). This article proves the technical feasibility and reduction of costs for ammonium removal from wastewater, investigates the underlying mechanisms and discusses future engineering needs.
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Affiliation(s)
| | - Christin Koch
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany.
| | - Maria D Balaguer
- LEQUiA, Institute of the Environment, University of Girona, Girona, Spain
| | - Jesús Colprim
- LEQUiA, Institute of the Environment, University of Girona, Girona, Spain
| | - Falk Harnisch
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Sebastià Puig
- LEQUiA, Institute of the Environment, University of Girona, Girona, Spain
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17
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Coskun D, Britto DT, Shi W, Kronzucker HJ. Nitrogen transformations in modern agriculture and the role of biological nitrification inhibition. NATURE PLANTS 2017; 3:17074. [PMID: 28585561 DOI: 10.1038/nplants.2017.74] [Citation(s) in RCA: 189] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 04/25/2017] [Indexed: 05/20/2023]
Abstract
The nitrogen (N)-use efficiency of agricultural plants is notoriously poor. Globally, about 50% of the N fertilizer applied to cropping systems is not absorbed by plants, but lost to the environment as ammonia (NH3), nitrate (NO3-), and nitrous oxide (N2O, a greenhouse gas with 300 times the heat-trapping capacity of carbon dioxide), raising agricultural production costs and contributing to pollution and climate change. These losses are driven by volatilization of NH3 and by a matrix of nitrification and denitrification reactions catalysed by soil microorganisms (chiefly bacteria and archaea). Here, we discuss mitigation of the harmful and wasteful process of agricultural N loss via biological nitrification inhibitors (BNIs) exuded by plant roots. We examine key recent discoveries in the emerging field of BNI research, focusing on BNI compounds and their specificity and transport, and discuss prospects for their role in improving agriculture while reducing its environmental impact.
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Affiliation(s)
- Devrim Coskun
- Department of Biological Sciences and Canadian Centre for World Hunger Research (CCWHR), University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Dev T Britto
- Department of Biological Sciences and Canadian Centre for World Hunger Research (CCWHR), University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Weiming Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Herbert J Kronzucker
- Department of Biological Sciences and Canadian Centre for World Hunger Research (CCWHR), University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
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18
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Huang X, Feng Y, Hu C, Xiao X, Yu D, Zou X. Mechanistic model for interpreting the toxic effects of sulfonamides on nitrification. JOURNAL OF HAZARDOUS MATERIALS 2016; 305:123-129. [PMID: 26651069 DOI: 10.1016/j.jhazmat.2015.11.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 06/05/2023]
Abstract
Antibiotics are categorized as pseudopersistent compounds because of their widespread use and continuous emission into the environment. Biological systems such as active sludge and biofilms are still the principal tools used to remove antibiotics in wastewater treatment plants (WWTPs). Consequently, it is important to determine the relationship between toxic effects in biological WWTPs and the structural characteristics of antibiotics. In the present study, toxic effects of 10 sulfonamides (SAs) on nitrification in an active sludge system were studied. The toxicity results (half-effective concentrations, EC50) indicated that the toxicity of sulfadimethoxine (SDM) is approximately 4 times as large as that of sulfadiazine (SD). Based on the toxicity mechanism and the partial least squares regression (PLS) method, an optimum quantitative structure-activity relationship (QSAR) model was developed for the test system. The mechanistic model showed that the pKa, the binding energies between SAs with dihydropteroate synthetase ( [Formula: see text] ) and the binding energies between SAs with ammonia monooxygenase ( [Formula: see text] ) are the key factors affecting the toxic effects of SAs on nitration process in active sludge system, following an order of importance of [Formula: see text] > [Formula: see text] >pKa.
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Affiliation(s)
- Xiangfeng Huang
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yi Feng
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Cui Hu
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; School of Life Science, Jinggangshan University, Ji'an 343009, China
| | - Xiaoyu Xiao
- School of Life Science, Jinggangshan University, Ji'an 343009, China
| | - Daliang Yu
- School of Life Science, Jinggangshan University, Ji'an 343009, China
| | - Xiaoming Zou
- School of Life Science, Jinggangshan University, Ji'an 343009, China.
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19
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Brandt KK, Amézquita A, Backhaus T, Boxall A, Coors A, Heberer T, Lawrence JR, Lazorchak J, Schönfeld J, Snape JR, Zhu YG, Topp E. Ecotoxicological assessment of antibiotics: A call for improved consideration of microorganisms. ENVIRONMENT INTERNATIONAL 2015; 85:189-205. [PMID: 26411644 DOI: 10.1016/j.envint.2015.09.013] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 09/03/2015] [Accepted: 09/10/2015] [Indexed: 05/06/2023]
Abstract
Antibiotics play a pivotal role in the management of infectious disease in humans, companion animals, livestock, and aquaculture operations at a global scale. Antibiotics are produced, consumed, and released into the environment at an unprecedented scale causing concern that the presence of antibiotic residues may adversely impact aquatic and terrestrial ecosystems. Here we critically review the ecotoxicological assessment of antibiotics as related to environmental risk assessment (ERA). We initially discuss the need for more specific protection goals based on the ecosystem service concept, and suggest that the ERA of antibiotics, through the application of a mode of toxic action approach, should make more use of ecotoxicological endpoints targeting microorganisms (especially bacteria) and microbial communities. Key ecosystem services provided by microorganisms and associated ecosystem service-providing units (e.g. taxa or functional groups) are identified. Approaches currently available for elucidating ecotoxicological effects on microorganisms are reviewed in detail and we conclude that microbial community-based tests should be used to complement single-species tests to offer more targeted protection of key ecosystem services. Specifically, we propose that ecotoxicological tests should not only assess microbial community function, but also microbial diversity (‘species’ richness) and antibiotic susceptibility. Promising areas for future basic and applied research of relevance to ERA are highlighted throughout the text. In this regard, the most fundamental knowledge gaps probably relate to our rudimentary understanding of the ecological roles of antibiotics in nature and possible adverse effects of environmental pollution with subinhibitory levels of antibiotics.
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Affiliation(s)
- Kristian K Brandt
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark; Sino Danish Center for Education and Research, Beijing, China.
| | - Alejandro Amézquita
- Unilever-Safety & Environmental Assurance Centre, Sharnbrook, United Kingdom
| | - Thomas Backhaus
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | | | - Anja Coors
- ECT Oekotoxikologie GmbH, Flörsheim/Main, Germany
| | - Thomas Heberer
- Federal Office of Consumer Protection and Food Safety, Department 3: Veterinary Drugs, Berlin, Germany
| | | | - James Lazorchak
- Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH, USA
| | - Jens Schönfeld
- Umweltbundesamt, Federal Environment Agency, Dessau, Germany
| | - Jason R Snape
- AstraZeneca Global Environment, Alderley Park, United Kingdom
| | - Yong-Guan Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Edward Topp
- Agriculture and Agri-Food Canada, London, Ontario, Canada.
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20
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Feld L, Hjelmsø MH, Nielsen MS, Jacobsen AD, Rønn R, Ekelund F, Krogh PH, Strobel BW, Jacobsen CS. Pesticide Side Effects in an Agricultural Soil Ecosystem as Measured by amoA Expression Quantification and Bacterial Diversity Changes. PLoS One 2015; 10:e0126080. [PMID: 25938467 PMCID: PMC4418756 DOI: 10.1371/journal.pone.0126080] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 03/29/2015] [Indexed: 11/26/2022] Open
Abstract
Background and Methods Assessing the effects of pesticide hazards on microbiological processes in the soil is currently based on analyses that provide limited insight into the ongoing processes. This study proposes a more comprehensive approach. The side effects of pesticides may appear as changes in the expression of specific microbial genes or as changes in diversity. To assess the impact of pesticides on gene expression, we focused on the amoA gene, which is involved in ammonia oxidation. We prepared soil microcosms and exposed them to dazomet, mancozeb or no pesticide. We hypothesized that the amount of amoA transcript decreases upon pesticide application, and to test this hypothesis, we used reverse-transcription qPCR. We also hypothesized that bacterial diversity is affected by pesticides. This hypothesis was investigated via 454 sequencing and diversity analysis of the 16S ribosomal RNA and RNA genes, representing the active and total soil bacterial communities, respectively. Results and Conclusion Treatment with dazomet reduced both the bacterial and archaeal amoA transcript numbers by more than two log units and produced long-term effects for more than 28 days. Mancozeb also inhibited the numbers of amoA transcripts, but only transiently. The bacterial and archaeal amoA transcripts were both sensitive bioindicators of pesticide side effects. Additionally, the numbers of bacterial amoA transcripts correlated with nitrate production in N-amended microcosms. Dazomet reduced the total bacterial numbers by one log unit, but the population size was restored after twelve days. The diversity of the active soil bacteria also seemed to be re-established after twelve days. However, the total bacterial diversity as reflected in the 16S ribosomal RNA gene sequences was largely dominated by Firmicutes and Proteobacteria at day twelve, likely reflecting a halt in the growth of early opportunists and the re-establishment of a more diverse population. We observed no effects of mancozeb on diversity.
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Affiliation(s)
- Louise Feld
- Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Copenhagen, Denmark
- * E-mail:
| | - Mathis Hjort Hjelmsø
- Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Copenhagen, Denmark
| | - Morten Schostag Nielsen
- Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Copenhagen, Denmark
| | - Anne Dorthe Jacobsen
- Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Copenhagen, Denmark
| | - Regin Rønn
- University of Copenhagen, Department of Biology, Section of Terrestrial Ecology, Copenhagen, Denmark
| | - Flemming Ekelund
- University of Copenhagen, Department of Biology, Section of Terrestrial Ecology, Copenhagen, Denmark
| | - Paul Henning Krogh
- University of Aarhus, Department of Bioscience, Section of Soil Fauna Ecology and Ecotoxicology, Silkeborg, Denmark
| | - Bjarne Westergaard Strobel
- University of Copenhagen, Department of Plant and Environmental Sciences, Section of Environmental Chemistry and Physics, Frederiksberg, Denmark
| | - Carsten Suhr Jacobsen
- Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Copenhagen, Denmark
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21
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Subbarao GV, Yoshihashi T, Worthington M, Nakahara K, Ando Y, Sahrawat KL, Rao IM, Lata JC, Kishii M, Braun HJ. Suppression of soil nitrification by plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 233:155-164. [PMID: 25711823 DOI: 10.1016/j.plantsci.2015.01.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 12/22/2014] [Accepted: 01/21/2015] [Indexed: 06/04/2023]
Abstract
Nitrification, the biological oxidation of ammonium to nitrate, weakens the soil's ability to retain N and facilitates N-losses from production agriculture through nitrate-leaching and denitrification. This process has a profound influence on what form of mineral-N is absorbed, used by plants, and retained in the soil, or lost to the environment, which in turn affects N-cycling, N-use efficiency (NUE) and ecosystem health and services. As reactive-N is often the most limiting in natural ecosystems, plants have acquired a range of mechanisms that suppress soil-nitrifier activity to limit N-losses via N-leaching and denitrification. Plants' ability to produce and release nitrification inhibitors from roots and suppress soil-nitrifier activity is termed 'biological nitrification inhibition' (BNI). With recent developments in methodology for in-situ measurement of nitrification inhibition, it is now possible to characterize BNI function in plants. This review assesses the current status of our understanding of the production and release of biological nitrification inhibitors (BNIs) and their potential in improving NUE in agriculture. A suite of genetic, soil and environmental factors regulate BNI activity in plants. BNI-function can be genetically exploited to improve the BNI-capacity of major food- and feed-crops to develop next-generation production systems with reduced nitrification and N2O emission rates to benefit both agriculture and the environment. The feasibility of such an approach is discussed based on the progresses made.
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Affiliation(s)
- Guntur Venkata Subbarao
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
| | - Tadashi Yoshihashi
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | | | - Kazuhiko Nakahara
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Yasuo Ando
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Kanwar Lal Sahrawat
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Andhra Pradesh, India
| | | | - Jean-Christophe Lata
- Sorbonne Universities, UPMC Univ. Paris 06, UMR 7618, InstitutiEESParis, Ecole Normale Superieure, 46 rue d'Ulm, 75230 Paris Cedex, France; Department of Geoecology and Geochemistry, Institute of Natural Resources, Tomsk Polytechnic University, 30, Lenin Street, Tomsk, 634050, Russia
| | - Masahiro Kishii
- CIMMYT (International Maize and Wheat Improvement Center), Apdo Postal 6-641, 06600 Mexico, D.F., Mexico
| | - Hans-Joachim Braun
- CIMMYT (International Maize and Wheat Improvement Center), Apdo Postal 6-641, 06600 Mexico, D.F., Mexico
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22
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Roslev P, Lentz T, Hesselsoe M. Microbial toxicity of methyl tert-butyl ether (MTBE) determined with fluorescent and luminescent bioassays. CHEMOSPHERE 2015; 120:284-291. [PMID: 25128634 DOI: 10.1016/j.chemosphere.2014.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/30/2014] [Accepted: 07/05/2014] [Indexed: 06/03/2023]
Abstract
The inhibitory effects of the fuel additive methyl tert-butyl ether (MTBE) and potential degradation products tert-butanol (TBA) and formaldehyde was examined using mixed microbial biomass, and six strains of bioluminescent bacteria and yeast. The purpose was to assess microbial toxicity with quantitative bioluminescent and fluorescent endpoints, and to identify sensitive proxies suitable for monitoring MTBE contamination. Bioluminescent Aliivibrio fischeri DSM 7151 (formerly Vibrio fischeri) appeared highly sensitive to MTBE exposure, and was a superior test organisms compared to lux-tagged Escherichia coli DH5α, Pseudomonas fluorescens DF57-40E7 and Saccharomyces cerevisiae BLYR. EC10 and EC50 for acute MTBE toxicity in A. fischeri were 1.1 and 10.9 mg L(-1), respectively. Long term (24h) MTBE exposure resulted in EC10 values of 0.01 mg L(-1). TBA was significantly less toxic with EC10 and EC50 for acute and chronic toxicity >1000 mg L(-1). Inhibition of bioluminescence was generally a more sensitive endpoint for MTBE toxicity than measuring intracellular ATP levels and heterotrophic CO2 assimilation. A weak estrogenic response was detected for MTBE at concentrations ⩾ 3.7 g L(-1) using an estrogen inducible bioluminescent yeast strain (S. cerevisiae BLYES). Microbial hydrolytic enzyme activity in groundwater was affected by MTBE with EC10 values of 0.5-787 mg L(-1), and EC50 values of 59-3073 for alkaline phosphatase, arylsulfatase, beta-1,4-glucanase, N-acetyl-beta-d-glucosaminidase, and leucine-aminopeptidase. Microbial alkaline phosphatase and beta-1,4-glucanase activity were most sensitive to MTBE exposure with EC50 ⩽ 64.8 mg L(-1). The study suggests that bioassays with luminescent A. fischeri, and fluorescent assays targeting hydrolytic enzyme activity are good candidates for monitoring microbial MTBE toxicity in contaminated water.
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Affiliation(s)
- Peter Roslev
- Section of Biology and Environmental Science, Aalborg University, DK-9000 Aalborg, Denmark.
| | - Trine Lentz
- Section of Biology and Environmental Science, Aalborg University, DK-9000 Aalborg, Denmark
| | - Martin Hesselsoe
- Amphi Consult ApS, Niels Jernes Vej 10, DK-9220 Aalborg, Denmark.
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Evaluation of the ecotoxicity of pollutants with bioluminescent microorganisms. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 145:65-135. [PMID: 25216953 DOI: 10.1007/978-3-662-43619-6_3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This chapter deals with the use of bioluminescent microorganisms in environmental monitoring, particularly in the assessment of the ecotoxicity of pollutants. Toxicity bioassays based on bioluminescent microorganisms are an interesting complement to classical toxicity assays, providing easiness of use, rapid response, mass production, and cost effectiveness. A description of the characteristics and main environmental applications in ecotoxicity testing of naturally bioluminescent microorganisms, covering bacteria and eukaryotes such as fungi and dinoglagellates, is reported in this chapter. The main features and applications of a wide variety of recombinant bioluminescent microorganisms, both prokaryotic and eukaryotic, are also summarized and critically considered. Quantitative structure-activity relationship models and hormesis are two important concepts in ecotoxicology; bioluminescent microorganisms have played a pivotal role in their development. As pollutants usually occur in complex mixtures in the environment, the use of both natural and recombinant bioluminescent microorganisms to assess mixture toxicity has been discussed. The main information has been summarized in tables, allowing quick consultation of the variety of luminescent organisms, bioluminescence gene systems, commercially available bioluminescent tests, environmental applications, and relevant references.
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Subbarao GV, Sahrawat KL, Nakahara K, Rao IM, Ishitani M, Hash CT, Kishii M, Bonnett DG, Berry WL, Lata JC. A paradigm shift towards low-nitrifying production systems: the role of biological nitrification inhibition (BNI). ANNALS OF BOTANY 2013; 112:297-316. [PMID: 23118123 PMCID: PMC3698375 DOI: 10.1093/aob/mcs230] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 09/19/2012] [Indexed: 05/15/2023]
Abstract
BACKGROUND Agriculture is the single largest geo-engineering initiative that humans have initiated on planet Earth, largely through the introduction of unprecedented amounts of reactive nitrogen (N) into ecosystems. A major portion of this reactive N applied as fertilizer leaks into the environment in massive amounts, with cascading negative effects on ecosystem health and function. Natural ecosystems utilize many of the multiple pathways in the N cycle to regulate N flow. In contrast, the massive amounts of N currently applied to agricultural systems cycle primarily through the nitrification pathway, a single inefficient route that channels much of this reactive N into the environment. This is largely due to the rapid nitrifying soil environment of present-day agricultural systems. SCOPE In this Viewpoint paper, the importance of regulating nitrification as a strategy to minimize N leakage and to improve N-use efficiency (NUE) in agricultural systems is highlighted. The ability to suppress soil nitrification by the release of nitrification inhibitors from plant roots is termed 'biological nitrification inhibition' (BNI), an active plant-mediated natural function that can limit the amount of N cycling via the nitrification pathway. The development of a bioassay using luminescent Nitrosomonas to quantify nitrification inhibitory activity from roots has facilitated the characterization of BNI function. Release of BNIs from roots is a tightly regulated physiological process, with extensive genetic variability found in selected crops and pasture grasses. Here, the current status of understanding of the BNI function is reviewed using Brachiaria forage grasses, wheat and sorghum to illustrate how BNI function can be utilized for achieving low-nitrifying agricultural systems. A fundamental shift towards ammonium (NH4(+))-dominated agricultural systems could be achieved by using crops and pastures with high BNI capacities. When viewed from an agricultural and environmental perspective, the BNI function in plants could potentially have a large influence on biogeochemical cycling and closure of the N loop in crop-livestock systems.
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Affiliation(s)
- G V Subbarao
- Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki, Japan.
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A potentiometric flow biosensor based on ammonia-oxidizing bacteria for the detection of toxicity in water. SENSORS 2013; 13:6936-45. [PMID: 23708274 PMCID: PMC3715250 DOI: 10.3390/s130606936] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/17/2013] [Accepted: 05/20/2013] [Indexed: 11/17/2022]
Abstract
A flow biosensor for the detection of toxicity in water using the ammonia-oxidizing bacterium (AOB) Nitrosomonas europaea as a bioreceptor and a polymeric membrane ammonium-selective electrode as a transducer is described. The system is based on the inhibition effects of toxicants on the activity of AOB, which can be evaluated by measuring the ammonium consumption rates with the ammonium-selective membrane electrode. The AOB cells are immobilized on polyethersulfone membranes packed in a holder, while the membrane electrode is placed downstream in the flow cell. Two specific inhibitors of the ammonia oxidation—allylthiourea and thioacetamide—have been tested. The IC50 values defined as the concentration of an inhibitor causing a 50% reduction in the ammonia oxidation activity have been measured as 0.17 μM and 0.46 μM for allylthiourea and thioacetamide, respectively. The proposed sensor offers advantages of simplicity, speed and high sensitivity for measuring toxicity in water.
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Stimulatory effect of xenobiotics on oxidative electron transport of chemolithotrophic nitrifying bacteria used as biosensing element. PLoS One 2013; 8:e53484. [PMID: 23326438 PMCID: PMC3541135 DOI: 10.1371/journal.pone.0053484] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 11/30/2012] [Indexed: 02/01/2023] Open
Abstract
Electron transport chain (ETCh) of ammonium (AOB) and nitrite oxidizing bacteria (NOB) participates in oxidation of ammonium to nitrate (nitrification). Operation of ETCh may be perturbed by a range of water-soluble xenobiotics. Therefore, consortia of nitrifying bacteria may be used as a biosensor to detect water contamination. A surprising feature of this system is an increase of oxygen consumption, detected in the presence of certain inhibitors of ETCh. Thus, to shed light on the mechanism of this effect (and other differences between inhibitors) we monitored separately respiration of the bacteria of the first (AOB - Nitrosomonas) and second (NOB -Nitrobacter) stages of nitrification. Furthermore, we measured plasma membrane potential and the level of reduction of NAD(P)H. We propose a novel model of ETCh in NOB to explain the role of reverse electron transport in the stimulation of oxygen consumption (previously attributed to hormesis).
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Potential for biological nitrification inhibition to reduce nitrification and N2O emissions in pasture crop–livestock systems. Animal 2013; 7 Suppl 2:322-32. [DOI: 10.1017/s1751731113000761] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Abstract
Modern agriculture has promoted the development of high-nitrification systems that are susceptible to major losses of nitrogen through leaching of nitrate and gaseous emissions of nitrogen oxide (NO and N2O), contributing to global warming and depletion of the ozone layer. Leakage of nitrogen from agricultural systems forces increased use of nitrogen fertilizers and causes water pollution and elevated costs of food production. Possible strategies for prevention of these processes involve various agricultural management approaches and use of synthetic inhibitors. Growing plants capable of producing nitrification suppressors could become a potentially superior method of controlling nitrification in the soil. There is a need to investigate the phenomenon of biological nitrification inhibition in arable crop species.
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Abstract
The study of traits of ammonia-oxidizing bacteria (AOB) by genetic transformation is an approach that is facilitated by the availability of AOB genome sequences. To transform an AOB, a vector construct is introduced into the cells by electroporation or conjugation to effect the inactivation, complementation, or expression of a selected gene. For inactivation studies, the vector construct should contain the gene of interest with an antibiotic resistance cassette and recombine into the cell's chromosome. For gene expression studies, a wide-host range vector with a transcriptional gene fusion can be used to test for gene roles. For gene complementation studies, a wide-host range vector expressing the inactivated gene can be used to recover the lost function in an AOB mutant strain. This chapter is a compilation of the methods that have been used to transform the AOB Nitrosomonas europaea and Nitrosospira multiformis and of the considerations and caveats to successfully produce, maintain, and store AOB transformants. The protocols may be applied to other AOB.
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Nguyen MD, Risgaard-Petersen N, Sørensen J, Brandt KK. Rapid and sensitive Nitrosomonas europaea biosensor assay for quantification of bioavailable ammonium sensu strictu in soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:1048-1054. [PMID: 21174468 DOI: 10.1021/es1030036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Knowledge on bioavailable ammonium sensu strictu (i.e., immediately available for cellular uptake) in soil is required to understand nutrient uptake processes in microorganisms and thus of vital importance for plant production. We here present a novel ammonium biosensor approach based on the lithoautotrophic ammonia-oxidizing bacterium Nitrosomonas europaea transformed with a luxAB sensor plasmid. Bioluminescence-based ammonium detection was achieved within 10 min with a quantification limit in liquid samples of ∼20 μM and a linear response range up to 400 μM. Biosensor and conventional chemical quantification of ammonium in soil solutions agreed well across a range of sample and assay conditions. The biosensor was subsequently applied for a solid phase-contact assay allowing for direct interaction of biosensor cells with soil particle-associated (i.e., exchangeable plus fixed) ammonium. The assay successfully quantified bioavailable ammonium even in unfertilized soil and demonstrated markedly higher ratios of bioavailable ammonium to water- or 2 M KCl-exchangeable ammonium in anoxic soil than in corresponding oxic soil. Particle-associated ammonium contributed by at least 74% and 93% of the total bioavailable pool in oxic and anoxic soil, respectively. The N. europaea biosensor should have broad relevance for environmental monitoring of bioavailable ammonium and processes depending on ammonium bioavailability.
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Affiliation(s)
- Minh Dong Nguyen
- Department of Agriculture and Ecology, Faculty of Life Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
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31
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Wang S, Gunsch CK. Effects of selected pharmaceutically active compounds on the ammonia oxidizing bacterium Nitrosomonas europaea. CHEMOSPHERE 2011; 82:565-72. [PMID: 20980043 DOI: 10.1016/j.chemosphere.2010.10.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 09/30/2010] [Accepted: 10/03/2010] [Indexed: 05/25/2023]
Abstract
Pharmaceutically active compounds (PhACs) are commonly found in wastewater influent. However, little research has focused on determining their impact on fundamental processes in wastewater treatment such as nitrogen removal. In this study, focus was placed on 4 commonly occurring PhACs (ketoprofen, naproxen, carbamazepine and gemfibrozil). Their effect was ascertained in the ammonia oxidizing bacterium (AOB), Nitrosomonas europaea in terms of membrane integrity and nitrite production. These PhACs were shown to inhibit nitrite production at concentrations of 1 and 10 μM while no effect was observed at 0.1 μM. The maximum observed nitrification inhibition was 25%, 29%, 22% and 26% for ketoprofen, naproxen, carbamazepine and gemfibrozil, respectively. A decrease in the live/dead ratio ranging from 10% to 16% suggests that these PhACs affect membrane integrity in N.europaea. The difference in nitrite production between PhACs treated cells and non PhAC treated controls was still significant following washing suggesting that inhibition is irreversible. Finally, nitrite production when adjusted to the live fraction of cells was also found to decrease suggesting that PhACs inhibited the activity of surviving cells. These results suggest that the presence of PhACs may affect AOB activity and may impact nitrogen removal, a key function in wastewater treatment. Follow up studies with additional AOB and in mixed culture are needed to further confirm these results.
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Affiliation(s)
- Shuyi Wang
- Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708, USA
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Pariasca Tanaka J, Nardi P, Wissuwa M. Nitrification inhibition activity, a novel trait in root exudates of rice. AOB PLANTS 2010; 2010:plq014. [PMID: 22476072 PMCID: PMC2992353 DOI: 10.1093/aobpla/plq014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/30/2010] [Accepted: 09/13/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Nitrification is an important process in soil--plant systems for providing plant-available nitrate (NO(3) (-)). However, NO(3) (-) is less stable in soils compared with ammonium (NH(4) (+)) and is more easily lost through leaching, runoff or denitrification. This study tested whether biological nitrification inhibition (BNI) activity is present in the root exudates of rice (Oryza sativa) and also the extent of variation between different genotypes. METHODOLOGY The BNI activity of root exudates was estimated by a bioluminescence assay using a recombinant Nitrosomonas europaea strain. Afterwards, the effect of a single application of concentrated root exudates and that of exudates deposited in the rhizosphere soil was tested on BNI using soil incubation. Soil was added with (NH(4))(2)SO(4) and water to reach 60 % of the water-holding capacity and incubated at 30 °C for different periods. Amounts of NH(4) (+) and NO(3) (-) were determined using a continuous-flow auto-analyser. PRINCIPAL RESULTS In an initial screening experiment, BNI activity in the exudates of 36 different rice genotypes was evaluated using a bioassay based on a recombinant Nitrosomonas strain. Significant genotypic variation was detected with the upland cultivar IAC25 demonstrating consistently high BNI activity, while modern lowland varieties like Nipponbare or IR64 exhibited lower activity. Subsequent experiments ruled out the possibility that BNI activity is simply due to non-specific (solute) leakage from roots. Soil incubation studies with concentrated root exudates of IAC25 showed significant reductions in NO(3) (-) formation. This effect was confirmed by detecting lower NO(3) (-) levels in incubation experiments using rhizosphere soil obtained from IAC25. CONCLUSIONS Our results provide first evidence that root exudates of rice can reduce nitrification rates in soil. Having shown this for a model crop, rice, offers possibilities for further exploitation of this phenomenon through molecular and genetic tools.
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Affiliation(s)
| | | | - Matthias Wissuwa
- Japan International Research Center for Agricultural Sciences (JIRCAS)Crop Production and Environment Division, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
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Figuerola ELM, Erijman L. Diversity of nitrifying bacteria in a full-scale petroleum refinery wastewater treatment plant experiencing unstable nitrification. JOURNAL OF HAZARDOUS MATERIALS 2010; 181:281-288. [PMID: 20570044 DOI: 10.1016/j.jhazmat.2010.05.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Revised: 03/27/2010] [Accepted: 05/03/2010] [Indexed: 05/29/2023]
Abstract
We have investigated bacterial populations relevant to nitrification in a full-scale activated sludge plant receiving wastewater from a petroleum refinery showing unstable nitrification. Inhibition of ammonia oxidation was related to phenol concentration according to a model of non-competitive inhibition. While the number of ammonia-oxidizing bacteria (AOB) did not correlate with nitrification performance, the total number of nitrite-oxidizing bacteria (NOB) dropped considerably during periods of nitrite accumulation or no nitrification. Diversity of nitrifiers in the sludge of the full-scale facility was examined at a time of full nitrification with the construction of clone libraries of ammonia monooxygenase (amoA) gene and of the 16S rRNA gene of NOB. Nucleotide sequences of amoA gene belonged to one dominant population, associated with Nitrosomonas europaea, and to a minor population related to the Nitrosomonas nitrosa lineage. The majority of sequences retrieved in the NOB-like clone library also clustered within a single operational taxonomic unit. The high dominance of Nitrobacter over Nitrospira and the low diversity of nitrifying bacteria observed in this wastewater treatment plant might account for the increased risk of failure in the presence of disturbances.
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Affiliation(s)
- Eva L M Figuerola
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI-CONICET), Buenos Aires, Argentina
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Nitrification and degradation of halogenated hydrocarbons--a tenuous balance for ammonia-oxidizing bacteria. Appl Microbiol Biotechnol 2010; 86:435-44. [PMID: 20146060 DOI: 10.1007/s00253-010-2454-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 01/14/2010] [Accepted: 01/14/2010] [Indexed: 10/19/2022]
Abstract
The process of nitrification has the potential for the in situ bioremediation of halogenated compounds provided a number of challenges can be overcome. In nitrification, the microbial process where ammonia is oxidized to nitrate, ammonia-oxidizing bacteria (AOB) are key players and are capable of carrying out the biodegradation of recalcitrant halogenated compounds. Through industrial uses, halogenated compounds often find their way into wastewater, contaminating the environment and bodies of water that supply drinking water. In the reclamation of wastewater, halogenated compounds can be degraded by AOB but can also be detrimental to the process of nitrification. This minireview considers the ability of AOB to carry out cometabolism of halogenated compounds and the consequent inhibition of nitrification. Possible cometabolism monitoring methods that were derived from current information about AOB genomes are also discussed. AOB expression microarrays have detected mRNA of genes that are expressed at higher levels during stress and are deemed "sentinel" genes. Promoters of selected "sentinel" genes have been cloned and used to drive the expression of gene-reporter constructs. The latter are being tested as early warning biosensors of cometabolism-induced damage in Nitrosomonas europaea with promising results. These and other biosensors may help to preserve the tenuous balance that exists when nitrification occurs in waste streams containing alternative AOB substrates such as halogenated hydrocarbons.
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Woznica A, Nowak A, Beimfohr C, Karczewski J, Bernas T. Monitoring structure and activity of nitrifying bacterial biofilm in an automatic biodetector of water toxicity. CHEMOSPHERE 2010; 78:1121-1128. [PMID: 20096440 DOI: 10.1016/j.chemosphere.2009.12.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 12/11/2009] [Accepted: 12/14/2009] [Indexed: 05/28/2023]
Abstract
Automatic biodetector of water toxicity is a biosensor based on monitoring of catalytic activity of the nitrifying bacteria. To create a standardized biosensing system, development of the biofilm must be characterized to determine the prerequisites for its biological (biocatalytic) stability. In this paper, growth of biofilm comprising ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the open cellular polyurethane material polyurethane sponge bioreactor has been investigated. Dynamics of the biofilm formation was estimated using AOB and NOB metabolic activity and the volume occupied by these two types of bacteria in the biofilm. Spectrophotometry liquid ion chromatography and image cytometry were used, respectively, for these measurements. A mathematical model of the dynamics of biofilm formation was established. These data indicate that open cellular polyurethane material is a good basis for the immobilization of nitrifying bacteria. Moreover, growth of the biofilm leads to its stable structural form, whose biocatalytic activity (12.29 for AOB and 6.84 micromol min(-1) for NOB) is constant in the long term.
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Affiliation(s)
- Andrzej Woznica
- Department of Biochemistry, Faculty of Biology and Environmental Protection, University of Silesia, Katowice, Poland.
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36
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Park S, Ely RL. Whole-genome transcriptional and physiological responses ofNitrosomonas europaeato cyanide: Identification of cyanide stress response genes. Biotechnol Bioeng 2009; 102:1645-53. [DOI: 10.1002/bit.22194] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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37
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Gvakharia BO, Bottomley PJ, Arp DJ, Sayavedra-Soto LA. Construction of recombinant Nitrosomonas europaea expressing green fluorescent protein in response to co-oxidation of chloroform. Appl Microbiol Biotechnol 2009; 82:1179-85. [PMID: 19247648 DOI: 10.1007/s00253-009-1914-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 02/05/2009] [Accepted: 02/08/2009] [Indexed: 11/29/2022]
Abstract
Transcriptional fusions with gfp driven by the promoter region of mbla (NE2571) in pPRO/mbla4 and clpB (NE2402) in pPRO/clpb7 were used to transform the ammonia-oxidizing bacterium Nitrosomonas europaea (ATCC 19718). The two genes were chosen because their transcript levels were found at much higher levels in N. europaea in response to oxidation of chloroform and chloromethane. In N. europaea transformed with pPRO/mbla4, green fluorescent protein (GFP)-dependent fluorescence increased from 3- to 18-fold above control levels in response to increasing chloroform concentrations (7 to 28 microM), and from 8- to 10-fold in response to increasing hydrogen peroxide concentrations (2.5-7.5 mM). The GFP-dependent fluorescence of N. europaea transformed with pPRO/clpb7 also showed an increase of 6- to 10-fold in response to chloroform (28-100 microM) but did not respond to H(2)O(2). Our data provide proof of concept that biosensors can be fabricated in ammonia-oxidizing bacteria using "sentinel" genes that up-regulate in response to stress caused either by co-oxidation of chlorinated solvents or by the presence of H(2)O(2). The fabricated biosensors had a consistent concentration-dependent response to chloroform; however, these did not respond to other chlorinated compounds that cause similar cellular stress.
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Affiliation(s)
- Barbara O Gvakharia
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
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Harper WF, Terada A, Poly F, Le Roux X, Kristensen K, Mazher M, Smets BF. The effect of hydroxylamine on the activity and aggregate structure of autotrophic nitrifying bioreactor cultures. Biotechnol Bioeng 2009; 102:714-24. [DOI: 10.1002/bit.22121] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Pagliaccia D, Merhaut D, Colao MC, Ruzzi M, Saccardo F, Stanghellini ME. Selective enhancement of the fluorescent pseudomonad population after amending the recirculating nutrient solution of hydroponically grown plants with a nitrogen stabilizer. MICROBIAL ECOLOGY 2008; 56:538-554. [PMID: 18347844 DOI: 10.1007/s00248-008-9373-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 01/11/2008] [Accepted: 02/05/2008] [Indexed: 05/26/2023]
Abstract
Fluorescent pseudomonads have been associated, via diverse mechanisms, with suppression of root disease caused by numerous fungal and fungal-like pathogens. However, inconsistent performance in disease abatement, after their employment, has been a problem. This has been attributed, in part, to the inability of the biocontrol bacterium to maintain a critical threshold population necessary for sustained biocontrol activity. Our results indicate that a nitrogen stabilizer (N-Serve, Dow Agrosciences) selectively and significantly enhanced, by two to three orders of magnitude, the resident population of fluorescent pseudomonads in the amended (i.e., 25 microg ml(-1) nitrapyrin, the active ingredient) and recycled nutrient solution used in the cultivation of hydroponically grown gerbera and pepper plants. Pseudomonas putida was confirmed as the predominant bacterium selectively enhanced. Terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rDNA suggested that N-Serve selectively increased P. putida and reduced bacterial diversity 72 h after application. In vitro tests revealed that the observed population increases of fluorescent pseudomonads were preceded by an early growth suppression of indigenous aerobic heterotrophic bacteria (AHB) population. Interestingly, the fluorescent pseudomonad population did not undergo this decrease, as shown in competition assays. Xylene and 1,2,4-trimethylbenzene (i.e., the inert ingredients in N-Serve) were responsible for a significant percentage of the fluorescent pseudomonad population increase. Furthermore, those increases were significantly higher when the active ingredient (i.e., nitrapyrin) and the inert ingredients were combined, which suggests a synergistic response. P. putida strains were screened for the ability to produce antifungal compounds and for the antifungal activity against Pythium aphanidermatum and Phytophthora capsici. The results of this study suggest the presence of diverse mechanisms with disease-suppressing potential. This study demonstrates the possibility of using a specific substrate to selectively enhance and maintain desired populations of a natural-occurring bacterium such as P. putida, a trait considered to have great potential in biocontrol applications for plant protection.
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Affiliation(s)
- D Pagliaccia
- Department of Plant Production, University of Tuscia, 01100, Viterbo, Italy.
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40
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Zakir HAKM, Subbarao GV, Pearse SJ, Gopalakrishnan S, Ito O, Ishikawa T, Kawano N, Nakahara K, Yoshihashi T, Ono H, Yoshida M. Detection, isolation and characterization of a root-exuded compound, methyl 3-(4-hydroxyphenyl) propionate, responsible for biological nitrification inhibition by sorghum (Sorghum bicolor). THE NEW PHYTOLOGIST 2008; 180:442-451. [PMID: 18657214 DOI: 10.1111/j.1469-8137.2008.02576.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nitrification results in poor nitrogen (N) recovery and negative environmental impacts in most agricultural systems. Some plant species release secondary metabolites from their roots that inhibit nitrification, a phenomenon known as biological nitrification inhibition (BNI). Here, we attempt to characterize BNI in sorghum (Sorghum bicolor). In solution culture, the effect of N nutrition and plant age was studied on BNI activity from roots. A bioluminescence assay using recombinant Nitrosomonas europaea was employed to determine the inhibitory effect of root exudates. One major active constituent was isolated by activity-guided HPLC fractionations. The structure was analysed using NMR and mass spectrometry. Properties and the 70% inhibitory concentration (IC(70)) of this compound were determined by in vitro assay. Sorghum had significant BNI capacity, releasing 20 allylthiourea units (ATU) g(-1) root DW d(-1). Release of BNI compounds increased with growth stage and concentration of supply. NH4+ -grown plants released several-fold higher BNI compounds than NO3- -grown plants. The active constituent was identified as methyl 3-(4-hydroxyphenyl) propionate. BNI compound release from roots is a physiologically active process, stimulated by the presence of NH4+. Methyl 3-(4-hydroxyphenyl) propionate is the first compound purified from the root exudates of any species; this is an important step towards better understanding BNI in sorghum.
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Affiliation(s)
- Hossain A K M Zakir
- Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Guntur V Subbarao
- Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Stuart J Pearse
- Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Subramaniam Gopalakrishnan
- Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Osamu Ito
- Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Takayuki Ishikawa
- Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Naoyoshi Kawano
- Crop production & Environment Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Kazuhiko Nakahara
- Food Science & Technology Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Tadashi Yoshihashi
- Food Science & Technology Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Hiroshi Ono
- National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
| | - Mitsuru Yoshida
- National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
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41
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Ortiz R, Sayre KD, Govaerts B, Gupta R, Subbarao G, Ban T, Hodson D, Dixon JM, Iván Ortiz-Monasterio J, Reynolds M. Climate change: Can wheat beat the heat? AGRICULTURE, ECOSYSTEMS & ENVIRONMENT 2008; 126:46-58. [PMID: 0 DOI: 10.1016/j.agee.2008.01.019] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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42
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Radniecki TS, Dolan ME, Semprini L. Physiological and transcriptional responses of Nitrosomonas europaea to toluene and benzene inhibition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:4093-4098. [PMID: 18589971 DOI: 10.1021/es702623s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ammonia oxidizing bacteria (AOB) are inhibited by many compounds found in wastewater treatment plant (WWTP) influent, including aromatic hydrocarbons. The detection of "sentinel genes" to identify the presence of aromatic hydrocarbons could be useful to WWTP operators. In this study, the transcriptomic responses of Nitrosomonas europaea during the cometabolism of benzene to phenol and toluene to benzyl alcohol and benzaldehyde were evaluated using whole genome Affymetrix microarrays and qRT-PCR. Benzyl alcohol and benzaldehyde were found not to inhibit N. europaea. However, phenol concentrations as low as 5 microM directly inhibited ammonia oxidation. Surprisingly, there were no significant up- or down-regulation of genes in N. europaea cells exposed to 20 microM toluene, which caused 50% inhibition of ammonia oxidation. Exposing N. europaea to 40 microM benzene, which caused a similar degree of inhibition, resulted in the up-regulation of seven adjacent genes, including NE 1545 (a putative pirin protein) and NE 1546 (a putative membrane protein), that appear to be involved with fatty-acid metabolism, lipid biosynthesis, and membrane protein synthesis. qRT-PCR analysis revealed that NE 1545 and NE 1546 were significantly up-regulated upon exposure to benzene and phenol, but not upon exposure to toluene. Transmission electron microscope images revealed a shift in outer cell structure in response to benzene exposure.
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Affiliation(s)
- Tyler S Radniecki
- School of Chemical, Biological and Environmental Engineering; 101 Gleeson Hall, Oregon State University, Corvallis, Oregon 97331, USA.
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43
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Morita M, Kudo N, Uemoto H, Watanabe A, Shinozaki H. Protective Effect of Immobilized Ammonia Oxidizers and Phenol-degrading Bacteria on Nitrification in Ammonia– and Phenol-containing Wastewater. Eng Life Sci 2007. [DOI: 10.1002/elsc.200700014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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44
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Gopalakrishnan S, Subbarao GV, Nakahara K, Yoshihashi T, Ito O, Maeda I, Ono H, Yoshida M. Nitrification Inhibitors from the root tissues of Brachiaria humidicola, a tropical grass. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:1385-8. [PMID: 17243702 DOI: 10.1021/jf062593o] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Nitrification inhibitory activity was found in root tissue extracts of Brachiaria humidicola, a tropical pasture grass. Two active inhibitory compounds were isolated by activity-guided fractionation, using recombinant Nitrosomonas europaea containing luxAB genes derived from the bioluminescent marine gram-negative bacterium Vibrio harveyi. The compounds were identified as methyl-p-coumarate and methyl ferulate, respectively. Their nitrification inhibitory properties were confirmed in chemically synthesized preparations of each. The IC50 values of chemically synthesized preparations were 19.5 and 4.4 microM, respectively. The ethyl, propyl, and butyl esters of p-coumaric and ferulic acids inhibited nitrification, whereas the free acid forms did not show inhibitory activity.
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Affiliation(s)
- Subramaniam Gopalakrishnan
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
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45
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Cui R, Chung WJ, Jahng D. A rapid and simple respirometric biosensor with immobilized cells of Nitrosomonas europaea for detecting inhibitors of ammonia oxidation. Biosens Bioelectron 2005; 20:1788-95. [PMID: 15681195 DOI: 10.1016/j.bios.2004.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Revised: 07/06/2004] [Accepted: 07/08/2004] [Indexed: 11/18/2022]
Abstract
As obligate chemolithotrophs, ammonia-oxidizing bacteria (AOB) grow very slowly and are known to be extremely sensitive to a wide variety of inhibitors. Since it is generally accepted that inhibition of ammonia oxidation by AOB results in a total failure of nitrogen removal, it is necessary to develop a method to detect inhibitors of ammonia oxidation in wastewater. Since ammonia oxidation accompanies oxygen consumption, ammonia oxidation can be easily evaluated by measuring oxygen consumption rate using a dissolved oxygen (DO) probe. In this study, a rapid and simple respirometric biosensor using the pure culture of Nitrosomonas europaea was developed. N. europaea was cultivated in a continuous fermentor operating at the dilution rate of 0.008 h(-1) to obtain physiologically constant cells and was immobilized onto the dialysis membrane through filtration. DO, determined by the biosensor, started to increase 30 s later after ammonia oxidation inhibitor was fed, and a new steady-state DO was obtained in 10-30 min. For this DO profile, steady-state kinetics was applied to evaluate ammonia oxidation efficiency. The concentration of a toxic compound causing 50% decrease of oxygen-consumption activity (EC50) was determined for different chemicals. The EC50 values obtained with the biosensor (0.018 mg l(-1) for allylthiourea, 0.027 mg l(-1) for thioacetamide, 1.10 mg l(-1) for phenol and 0.0 1mg l(-1) for thiourea) indicated that the developed biosensor was highly sensitive to a variety of the inhibitors. It was also shown that the biosensor is applicable for on-line real time monitoring.
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Affiliation(s)
- Rong Cui
- Department of Environmental Engineering and Biotechnology, Myongji University, San 38-2, Namdong, Yongin, Kyonggido 449-728, Republic of Korea
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46
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Brandt KK, Jørgensen NO, Nielsen TH, Winding A. Microbial community-level toxicity testing of linear alkylbenzene sulfonates in aquatic microcosms. FEMS Microbiol Ecol 2004; 49:229-41. [DOI: 10.1016/j.femsec.2004.03.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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47
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Kelly CJ, Tumsaroj N, Lajoie CA. Assessing wastewater metal toxicity with bacterial bioluminescence in a bench-scale wastewater treatment system. WATER RESEARCH 2004; 38:423-431. [PMID: 14675654 DOI: 10.1016/s0043-1354(03)00432-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effectiveness of a previously developed toxicity monitoring method for activated sludge wastewater treatment employing a bioluminescent bacterium (Shk1) was evaluated in batch experiments and a bench-scale activated sludge system exposed to heavy metals (Cu, Zn, Ni, and Cd). Influent wastewater (primary clarifier supernatant) and activated sludge from a municipal wastewater treatment plant were used in both batch experiments and in the bench-scale wastewater treatment system. Shk1 bioluminescence was most sensitive to Cd and Zn, followed by Cu, and then Ni in order of decreasing sensitivity. In contrast, activated sludge specific oxygen uptake rate was most sensitive to Cu, followed by Cd and Zn, and finally Ni. The same pattern of sensitivity was observed in batch and bench-scale evaluations. Batch experiments examining the effect of metal adsorption were performed. The adsorption of metals to activated sludge and reduction in bioavailability due to chelation by soluble organics or by precipitation in wastewater was found to be an important effect in mediating differences in toxicity response between bioluminescence and respirometry. Batch adsorption experiments indicated that the activated sludge adsorption capacity was highest for Cu, followed by Cd, Ni, and then Zn. A simple mathematical model for the soluble metal concentration in the aeration basin and clarifier was developed utilizing metal distribution coefficients determined from the batch adsorption experiments. Model predictions compared well with results from the bench-scale activated sludge experiments.
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Affiliation(s)
- Christine J Kelly
- Department of Chemical Engineering and Materials Science, Syracuse University, 220 Hinds Hall, Syracuse, NY 13244-01190, USA.
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49
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Brandt KK, Pedersen A, Sørensen J. Solid-phase contact assay that uses a lux-marked Nitrosomonas europaea reporter strain to estimate toxicity of bioavailable linear alkylbenzene sulfonate in soil. Appl Environ Microbiol 2002; 68:3502-8. [PMID: 12089034 PMCID: PMC126794 DOI: 10.1128/aem.68.7.3502-3508.2002] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Information about in situ toxicity of the bioavailable pools of adsorptive soil pollutants is a prerequisite for proper ecological risk assessment in contaminated soils. Such toxicity data may be obtained by assays allowing for direct exposure of introduced test microorganisms to the toxicants, as they appear in solid solution equilibria in the natural soil. We describe a novel sensitive solid-phase contact assay for in situ toxicity testing of soil pollutants based on a recombinant bioluminescent reporter strain of Nitrosomonas europaea. A slurry of the reporter strain and soil sample was shaken for 1 h, after which bioluminescence was measured either directly (soil slurry protocol) or in the supernatant obtained after centrifugation (soil extract protocol). The assay was validated for both protocols by using linear alkylbenzene sulfonate (LAS) as a toxic and adsorptive model compound in the soil samples. Interestingly, LAS showed the same toxicity to the reporter strain with either soil incubation (both protocols) or pure culture, suggesting that adsorbed LAS pools contributed to the observed toxicity. The solid-phase contact assay that used the reporter strain of lux-marked N. europaea was slightly more sensitive for the detection of LAS toxicity in soil than activity-based assays targeting indigenous nitrifiers and much more sensitive than assays targeting indigenous heterotrophic microbes. We conclude that the new solid-phase contact assay, which is based on direct interaction of the test microorganisms with bioavailable pools of the toxicants in soil, provides a most sensitive and relevant method for evaluating the in situ toxicity and assessing the risks of soil contaminants.
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Affiliation(s)
- Kristian K Brandt
- Section of Genetics and Microbiology, Department of Ecology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
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