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Partipilo G, Bowman EK, Palmer EJ, Gao Y, Ridley RS, Alper HS, Keitz BK. Single-Cell Phenotyping of Extracellular Electron Transfer via Microdroplet Encapsulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.13.598847. [PMID: 38915652 PMCID: PMC11195189 DOI: 10.1101/2024.06.13.598847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Electroactive organisms contribute to metal cycling, pollutant removal, and other redox-driven environmental processes. Studying this phenomenon in high-throughput is challenging since extracellular reduction cannot easily be traced back to its cell of origin within a mixed population. Here, we describe the development of a microdroplet emulsion system to enrich EET-capable organisms. We validated our system using the model electroactive organism S. oneidensis and describe the tooling of a benchtop microfluidic system for oxygen-limited processes. We demonstrated enrichment of EET-capable phenotypes from a mixed wild-type and EET-knockout population. As a proof-of-concept application, bacteria were collected from iron sedimentation from Town Lake (Austin, TX) and subjected to microdroplet enrichment. We observed an increase in EET-capable organisms in the sorted population that was distinct when compared to a population enriched in a bulk culture more closely akin to traditional techniques for discovering EET-capable bacteria. Finally, two bacterial species, C. sakazakii and V. fessus not previously shown to be electroactive, were further cultured and characterized for their ability to reduce channel conductance in an organic electrochemical transistor (OECT) and to reduce soluble Fe(III). We characterized two bacterial species not previously shown to exhibit electrogenic behavior. Our results demonstrate the utility of a microdroplet emulsions for identifying putative EET-capable bacteria and how this technology can be leveraged in tandem with existing methods.
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Affiliation(s)
- Gina Partipilo
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, 78712
| | - Emily K. Bowman
- Interdisciplinary Life Sciences Graduate Program, University of Texas at Austin, Austin, TX, 78712
| | - Emma J. Palmer
- Civil, Architectural, and Environmental Engineering, University of Texas at Austin, Austin, TX, 78712
| | - Yang Gao
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, 78712
| | - Rodney S. Ridley
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, 78712
| | - Hal S. Alper
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, 78712
| | - Benjamin K. Keitz
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, 78712
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2
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Franco A, Chukwubuikem A, Meiners C, Rosenbaum MA. Exploring phenazine electron transfer interaction with elements of the respiratory pathways of Pseudomonas putida and Pseudomonas aeruginosa. Bioelectrochemistry 2024; 157:108636. [PMID: 38181591 DOI: 10.1016/j.bioelechem.2023.108636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/20/2023] [Accepted: 12/23/2023] [Indexed: 01/07/2024]
Abstract
Pseudomonas aeruginosa phenazines contribute to survival under microaerobic and anaerobic conditions by extracellular electron discharge to regulate cellular redox balances. This electron discharge is also attractive to be used for bioelectrochemical applications. However, elements of the respiratory pathways that interact with phenazines are not well understood. Five terminal oxidases are involved in the aerobic electron transport chain (ETC) of Pseudomonas putida and P. aeruginosa. The latter bacterium also includes four reductases that allow for denitrification. Here, we explored if phenazine-1-carboxylic acid interacts with those elements to enhance anodic electron discharge and drive bacterial growth in oxygen-limited conditions. Bioelectrochemical evaluations of terminal oxidase-deficient mutants of both Pseudomonas strains and P. aeruginosa with stimulated denitrification pathways indicated no direct beneficial interaction of phenazines with ETC elements for extracellular electron discharge. However, the single usage of the Cbb3-2 oxidase increased phenazine production, electron discharge, and cell growth. Assays with purified periplasmic cytochromes NirM and NirS indicated that pyocyanin acts as their electron donor. We conclude that phenazines play an important role in electron transfer to, between, and from terminal oxidases under oxygen-limiting conditions and their modulation might enhance EET. However, the phenazine-anode interaction cannot replace oxygen respiration to deliver energy for biomass formation.
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Affiliation(s)
- Angel Franco
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Anthony Chukwubuikem
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), Fürstengraben 1, 07743 Jena, Germany
| | - Carina Meiners
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), Fürstengraben 1, 07743 Jena, Germany
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), Fürstengraben 1, 07743 Jena, Germany.
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3
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Bényei ÉB, Nazeer RR, Askenasy I, Mancini L, Ho PM, Sivarajan GAC, Swain JEV, Welch M. The past, present and future of polymicrobial infection research: Modelling, eavesdropping, terraforming and other stories. Adv Microb Physiol 2024; 85:259-323. [PMID: 39059822 DOI: 10.1016/bs.ampbs.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Over the last two centuries, great advances have been made in microbiology as a discipline. Much of this progress has come about as a consequence of studying the growth and physiology of individual microbial species in well-defined laboratory media; so-called "axenic growth". However, in the real world, microbes rarely live in such "splendid isolation" (to paraphrase Foster) and more often-than-not, share the niche with a plethora of co-habitants. The resulting interactions between species (and even between kingdoms) are only very poorly understood, both on a theoretical and experimental level. Nevertheless, the last few years have seen significant progress, and in this review, we assess the importance of polymicrobial infections, and show how improved experimental traction is advancing our understanding of these. A particular focus is on developments that are allowing us to capture the key features of polymicrobial infection scenarios, especially as those associated with the human airways (both healthy and diseased).
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Affiliation(s)
| | | | - Isabel Askenasy
- Department of Biochemistry, Tennis Court Road, Cambridge, United Kingdom
| | - Leonardo Mancini
- Department of Biochemistry, Tennis Court Road, Cambridge, United Kingdom
| | - Pok-Man Ho
- Department of Biochemistry, Tennis Court Road, Cambridge, United Kingdom
| | | | - Jemima E V Swain
- Department of Biochemistry, Tennis Court Road, Cambridge, United Kingdom
| | - Martin Welch
- Department of Biochemistry, Tennis Court Road, Cambridge, United Kingdom.
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4
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Shao Z, Guo R, Tang J, Zhang X. Effect of Pseudomonas aeruginosa on Corrosion Behavior of X65 Carbon Steel. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2428. [PMID: 38793494 PMCID: PMC11123138 DOI: 10.3390/ma17102428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/01/2024] [Accepted: 05/13/2024] [Indexed: 05/26/2024]
Abstract
X65 pipeline steel is widely used in the field of offshore oil and gas exploitation due to its excellent performance. However, due to the complex environment in the ocean, X65 pipeline steel is faced with a great risk of microbial corrosion failure. Therefore, it is of great significance to study the corrosion mechanism of X65 pipeline steel by microorganisms. In this paper, the corrosion effect of Pseudomonas aeruginosa (P. aeruginosa) secreting phenazine compounds on X65 pipeline steel was studied by the weight loss method, biofilm scanning electron microscopy analysis, surface corrosion morphology observation, electrochemical testing and medium pH test corrosion products. The results showed that the inoculation of P. aeruginosa accelerated the corrosion of X65 steel. After knocking out the phzM and phzS genes that regulate the synthesis of PYO, P. aeruginosa can still produce biofilms on the surface of X65 steel consistent with the morphology of wild-type P. aeruginosa, but the corrosion of X65 steel is significantly reduced. It is proved that PYO plays an important role in the corrosion process of P. aeruginosa on steel.
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Affiliation(s)
- Zixuan Shao
- School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China; (Z.S.); (R.G.)
| | - Ruiqi Guo
- School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China; (Z.S.); (R.G.)
| | - Jianhua Tang
- China National Offshore Oil Corporation, Beijing 100010, China;
| | - Xin Zhang
- School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China; (Z.S.); (R.G.)
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5
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Tsypin LMZ, Saunders SH, Chen AW, Newman DK. Genetically dissecting the electron transport chain of a soil bacterium reveals a generalizable mechanism for biological phenazine-1-carboxylic acid oxidation. PLoS Genet 2024; 20:e1011064. [PMID: 38709821 PMCID: PMC11108179 DOI: 10.1371/journal.pgen.1011064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 05/21/2024] [Accepted: 03/25/2024] [Indexed: 05/08/2024] Open
Abstract
The capacity for bacterial extracellular electron transfer via secreted metabolites is widespread in natural, clinical, and industrial environments. Recently, we discovered the biological oxidation of phenazine-1-carboxylic acid (PCA), the first example of biological regeneration of a naturally produced extracellular electron shuttle. However, it remained unclear how PCA oxidation was catalyzed. Here, we report the mechanism, which we uncovered by genetically perturbing the branched electron transport chain (ETC) of the soil isolate Citrobacter portucalensis MBL. Biological PCA oxidation is coupled to anaerobic respiration with nitrate, fumarate, dimethyl sulfoxide, or trimethylamine-N-oxide as terminal electron acceptors. Genetically inactivating the catalytic subunits for all redundant complexes for a given terminal electron acceptor abolishes PCA oxidation. In the absence of quinones, PCA can still donate electrons to certain terminal reductases, albeit much less efficiently. In C. portucalensis MBL, PCA oxidation is largely driven by flux through the ETC, which suggests a generalizable mechanism that may be employed by any anaerobically respiring bacterium with an accessible cytoplasmic membrane. This model is supported by analogous genetic experiments during nitrate respiration by Pseudomonas aeruginosa.
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Affiliation(s)
- Lev M. Z. Tsypin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Scott H. Saunders
- Green Center for Systems Biology—Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Allen W. Chen
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Dianne K. Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, United States of America
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6
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Kou B, Yuan Y, Zhu X, Ke Y, Wang H, Yu T, Tan W. Effect of soil organic matter-mediated electron transfer on heavy metal remediation: Current status and perspectives. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170451. [PMID: 38296063 DOI: 10.1016/j.scitotenv.2024.170451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/18/2024] [Accepted: 01/24/2024] [Indexed: 02/05/2024]
Abstract
Soil contamination by heavy metals poses major risks to human health and the environment. Given the current status of heavy metal pollution, many remediation techniques have been tested at laboratory and contaminated sites. The effects of soil organic matter-mediated electron transfer on heavy metal remediation have not been adequately studied, and the key mechanisms underlying this process have not yet been elucidated. In this review, microbial extracellular electron transfer pathways, organic matter electron transfer for heavy metal reduction, and the factors affecting these processes were discussed to enhance our understanding of heavy metal pollution. It was found that microbial extracellular electrons delivered by electron shuttles have the longest distance among the three electron transfer pathways, and the application of exogenous electron shuttles lays the foundation for efficient and persistent remediation of heavy metals. The organic matter-mediated electron transfer process, wherein organic matter acts as an electron shuttle, promotes the conversion of high valence state metal ions, such as Cr(VI), Hg(II), and U(VI), into less toxic and morphologically stable forms, which inhibits their mobility and bioavailability. Soil type, organic matter structural and content, heavy metal concentrations, and environmental factors (e.g., pH, redox potential, oxygen conditions, and temperature) all influence organic matter-mediated electron transfer processes and bioremediation of heavy metals. Organic matter can more effectively mediate electron transfer for heavy metal remediation under anaerobic conditions, as well as when the heavy metal content is low and the redox potential is suitable under fluvo-aquic/paddy soil conditions. Organic matter with high aromaticity, quinone groups, and phenol groups has a stronger electron transfer ability. This review provides new insights into the control and management of soil contamination and heavy metal remediation technologies.
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Affiliation(s)
- Bing Kou
- College of Urban and Environmental Science, Northwest University, Xi'an 710127, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Ying Yuan
- State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
| | - Xiaoli Zhu
- College of Urban and Environmental Science, Northwest University, Xi'an 710127, China.
| | - Yuxin Ke
- College of Urban and Environmental Science, Northwest University, Xi'an 710127, China
| | - Hui Wang
- State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Tingqiao Yu
- International Education College, Beijing Vocational College of Agriculture, Beijing 102442, China
| | - Wenbing Tan
- State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
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7
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He Y, Yun H, Peng L, Ji J, Wang W, Li X. Deciphering the potential role of quorum quenching in efficient aerobic denitrification driven by a synthetic microbial community. WATER RESEARCH 2024; 251:121162. [PMID: 38277828 DOI: 10.1016/j.watres.2024.121162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/03/2024] [Accepted: 01/16/2024] [Indexed: 01/28/2024]
Abstract
Low efficiency is one of the main challenges for the application of aerobic denitrification technology in wastewater treatment. To improve denitrification efficiency, a synthetic microbial community (SMC) composed of denitrifiers Acinetobacter baumannii N1 (AC), Pseudomonas aeruginosa N2 (PA) and Aeromonas hydrophila (AH) were constructed. The nitrate (NO3--N) reduction efficiency of the SMC reached 97 % with little nitrite (NO2--N) accumulation, compared to the single-culture systems and co-culture systems. In the SMC, AH proved to mainly contribute to NO3--N reduction with the assistance of AC, while PA exerted NO2--N reduction. AC and AH secreted N-hexanoyl-DL-homoserine lactone (C6-HSL) to promote the electron transfer from the quinone pool to nitrate reductase. The declined N-(3-oxododecanoyl)-L-homoserine lactone (3OC12-HSL), resulting from quorum quenching (QQ) by AH, stimulated the excretion of pyocyanin, which could improve the electron transfer from complex III to downstream denitrifying enzymes for NO2--N reduction. In addition, C6-HSL mainly secreted by PA led to the up-regulation of TCA cycle-related genes and provided sufficient energy (such as NADH and ATP) for aerobic denitrification. In conclusion, members of the SMC achieved efficient denitrification through the interactions between QQ, electron transfer, and energy metabolism induced by N-acyl-homoserine lactones (AHLs). This study provided a theoretical basis for the engineering application of synthetic microbiome to remove nitrate wastewater.
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Affiliation(s)
- Yue He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshui South Road #222, Lanzhou 730000, China
| | - Hui Yun
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshui South Road #222, Lanzhou 730000, China; Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Sciences, Lanzhou University, Tianshui South Road #222, Lanzhou 730000, China.
| | - Liang Peng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshui South Road #222, Lanzhou 730000, China
| | - Jing Ji
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshui South Road #222, Lanzhou 730000, China
| | - Wenxue Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshui South Road #222, Lanzhou 730000, China
| | - Xiangkai Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Tianshui South Road #222, Lanzhou 730000, China; Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Sciences, Lanzhou University, Tianshui South Road #222, Lanzhou 730000, China.
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8
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Smiley MK, Sekaran DC, Forouhar F, Wolin E, Jovanovic M, Price-Whelan A, Dietrich LEP. MpaR-driven expression of an orphan terminal oxidase subunit supports Pseudomonas aeruginosa biofilm respiration and development during cyanogenesis. mBio 2024; 15:e0292623. [PMID: 38112469 PMCID: PMC10790758 DOI: 10.1128/mbio.02926-23] [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: 11/03/2023] [Accepted: 11/10/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE Cyanide is an inhibitor of heme-copper oxidases, which are required for aerobic respiration in all eukaryotes and many prokaryotes. This fast-acting poison can arise from diverse sources, but mechanisms by which bacteria sense it are poorly understood. We investigated the regulatory response to cyanide in the pathogenic bacterium Pseudomonas aeruginosa, which produces cyanide as a virulence factor. Although P. aeruginosa has the capacity to produce a cyanide-resistant oxidase, it relies primarily on heme-copper oxidases and even makes additional heme-copper oxidase proteins specifically under cyanide-producing conditions. We found that the protein MpaR controls expression of cyanide-inducible genes in P. aeruginosa and elucidated the molecular details of this regulation. MpaR contains a DNA-binding domain and a domain predicted to bind pyridoxal phosphate (vitamin B6), a compound that is known to react spontaneously with cyanide. These observations provide insight into the understudied phenomenon of cyanide-dependent regulation of gene expression in bacteria.
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Affiliation(s)
- Marina K. Smiley
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Doran C. Sekaran
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Farhad Forouhar
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York, USA
| | - Erica Wolin
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Marko Jovanovic
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Lars E. P. Dietrich
- Department of Biological Sciences, Columbia University, New York, New York, USA
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9
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Tsypin LM, Saunders SH, Chen AW, Newman DK. Genetically dissecting the electron transport chain of a soil bacterium reveals a generalizable mechanism for biological phenazine-1-carboxylic acid oxidation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.567096. [PMID: 38014283 PMCID: PMC10680695 DOI: 10.1101/2023.11.14.567096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The capacity for bacterial extracellular electron transfer via secreted metabolites is widespread in natural, clinical, and industrial environments. Recently, we discovered biological oxidation of phenazine-1-carboxylic acid (PCA), the first example of biological regeneration of a naturally produced extracellular electron shuttle. However, it remained unclear how PCA oxidation was catalyzed. Here, we report the mechanism, which we uncovered by genetically perturbing the branched electron transport chain (ETC) of the soil isolate Citrobacter portucalensis MBL. Biological PCA oxidation is coupled to anaerobic respiration with nitrate, fumarate, dimethyl sulfoxide, or trimethylamine-N-oxide as terminal electron acceptors. Genetically inactivating the catalytic subunits for all redundant complexes for a given terminal electron acceptor abolishes PCA oxidation. In the absence of quinones, PCA can still donate electrons to certain terminal reductases, albeit much less efficiently. In C. portucalensis MBL, PCA oxidation is largely driven by flux through the ETC, which suggests a generalizable mechanism that may be employed by any anaerobically respiring bacterium with an accessible cytoplasmic membrane. This model is supported by analogous genetic experiments during nitrate respiration by Pseudomonas aeruginosa.
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Affiliation(s)
- Lev M.Z. Tsypin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Scott H. Saunders
- Green Center for Systems Biology - Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Allen W. Chen
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Dianne K. Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
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10
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Ma W, Zhang X, Han H, Shi X, Kong Q, Yu T, Zhao F. Novel strategy to enhance the biological treatment of coal chemical wastewater by nano-zero valent iron loaded fly ash-based activated carbon assisted activated sludge process. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:110550-110561. [PMID: 37792192 DOI: 10.1007/s11356-023-29904-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 09/11/2023] [Indexed: 10/05/2023]
Abstract
Industrial waste as novel conductive mediator was applied for wastewater treatment as a novel strategy for both waste recycling and sustainable development of wastewater treatment. In this study, nanoscale zero valent iron-loaded fly ash-based activated carbon (nZVI@FABAC) was prepared and applied to enhancing activated sludge (AS) process for coal chemical wastewater (CCW) treatment. The results demonstrated that the removal efficiencies of COD and total phenols (TPh) in nZVI@FABAC/AS process reached about 83.96 and 85.17%, which increased 52.51 and 31.52% compared with the single AS process, respectively. And the acute toxic unit value of CCW was reduced by 88.24% after nZVI@FABAC/AS process treatment. The various functional bacteria including phenol-degrading bacteria (Comamonas and Acinetobacter), electroactive bacteria (Geobacter), and iron reduction bacteria (Geothrix) were enriched in the nZVI@FABAC/AS process, which provided various electron transfer pathways to improve the degradation of toxic organics in CCW. Accordingly, nZVI@FABAC/AS process provided a promising and sustainable way for industrial wastewater treatment.
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Affiliation(s)
- Weiwei Ma
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266520, China
| | - Xiaoqi Zhang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266520, China
| | - Hongjun Han
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Xueqing Shi
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266520, China.
| | - Qiaoping Kong
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266520, China
| | - Tong Yu
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266520, China
| | - Fei Zhao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266520, China
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11
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Evans CR, Smiley MK, Asahara Thio S, Wei M, Florek LC, Dayton H, Price-Whelan A, Min W, Dietrich LEP. Spatial heterogeneity in biofilm metabolism elicited by local control of phenazine methylation. Proc Natl Acad Sci U S A 2023; 120:e2313208120. [PMID: 37847735 PMCID: PMC10614215 DOI: 10.1073/pnas.2313208120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/15/2023] [Indexed: 10/19/2023] Open
Abstract
Within biofilms, gradients of electron acceptors such as oxygen stimulate the formation of physiological subpopulations. This heterogeneity can enable cross-feeding and promote drug resilience, features of the multicellular lifestyle that make biofilm-based infections difficult to treat. The pathogenic bacterium Pseudomonas aeruginosa produces pigments called phenazines that can support metabolic activity in hypoxic/anoxic biofilm subzones, but these compounds also include methylated derivatives that are toxic to their producer under some conditions. In this study, we uncover roles for the global regulators RpoS and Hfq/Crc in controlling the beneficial and detrimental effects of methylated phenazines in biofilms. Our results indicate that RpoS controls phenazine methylation by modulating activity of the carbon catabolite repression pathway, in which the Hfq/Crc complex inhibits translation of the phenazine methyltransferase PhzM. We find that RpoS indirectly inhibits expression of CrcZ, a small RNA that binds to and sequesters Hfq/Crc, specifically in the oxic subzone of P. aeruginosa biofilms. Deletion of rpoS or crc therefore leads to overproduction of methylated phenazines, which we show leads to increased metabolic activity-an apparent beneficial effect-in hypoxic/anoxic subpopulations within biofilms. However, we also find that under specific conditions, biofilms lacking RpoS and/or Crc show increased sensitivity to phenazines indicating that the increased metabolic activity in these mutants comes at a cost. Together, these results suggest that complex regulation of PhzM allows P. aeruginosa to simultaneously exploit the benefits and limit the toxic effects of methylated phenazines.
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Affiliation(s)
| | - Marina K. Smiley
- Department of Biological Sciences, Columbia University, New York, NY10027
| | - Sean Asahara Thio
- Department of Biological Sciences, Columbia University, New York, NY10027
| | - Mian Wei
- Department of Chemistry, Columbia University, New York, NY10027
| | - Lindsey C. Florek
- Department of Biological Sciences, Columbia University, New York, NY10027
| | - Hannah Dayton
- Department of Biological Sciences, Columbia University, New York, NY10027
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, NY10027
| | - Wei Min
- Department of Chemistry, Columbia University, New York, NY10027
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12
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Smith HB, Lee K, Freeman MJ, Stevenson DM, Amador-Noguez D, Sauer JD. Listeria monocytogenes requires DHNA-dependent intracellular redox homeostasis facilitated by Ndh2 for survival and virulence. Infect Immun 2023; 91:e0002223. [PMID: 37754681 PMCID: PMC10580952 DOI: 10.1128/iai.00022-23] [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: 01/12/2023] [Accepted: 08/09/2023] [Indexed: 09/28/2023] Open
Abstract
Listeria monocytogenes is a remarkably well-adapted facultative intracellular pathogen that can thrive in a wide range of ecological niches. L. monocytogenes maximizes its ability to generate energy from diverse carbon sources using a respiro-fermentative metabolism that can function under both aerobic and anaerobic conditions. Cellular respiration maintains redox homeostasis by regenerating NAD+ while also generating a proton motive force. The end products of the menaquinone (MK) biosynthesis pathway are essential to drive both aerobic and anaerobic cellular respirations. We previously demonstrated that intermediates in the MK biosynthesis pathway, notably 1,4-dihydroxy-2-naphthoate (DHNA), are required for the survival and virulence of L. monocytogenes independent of their role in respiration. Furthermore, we found that restoration of NAD+/NADH ratio through expression of water-forming NADH oxidase could rescue phenotypes associated with DHNA deficiency. Here, we extend these findings to demonstrate that endogenous production or direct supplementation of DHNA restored both the cellular redox homeostasis and metabolic output of fermentation in L. monocytogenes. Furthermore, exogenous supplementation of DHNA rescues the in vitro growth and ex vivo virulence of L. monocytogenes DHNA-deficient mutants. Finally, we demonstrate that exogenous DHNA restores redox balance in L. monocytogenes specifically through the recently annotated NADH dehydrogenase Ndh2, independent of its role in the extracellular electron transport pathway. These data suggest that the production of DHNA may represent an additional layer of metabolic adaptability by L. monocytogenes to drive energy metabolism in the absence of respiration-favorable conditions.
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Affiliation(s)
- Hans B. Smith
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kijeong Lee
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Matthew J. Freeman
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - David M. Stevenson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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13
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Jiménez Otero F, Newman DK, Tender LM. Pyocyanin-dependent electrochemical inhibition of Pseudomonas aeruginosa biofilms is synergistic with antibiotic treatment. mBio 2023; 14:e0070223. [PMID: 37314185 PMCID: PMC10470778 DOI: 10.1128/mbio.00702-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 04/19/2023] [Indexed: 06/15/2023] Open
Abstract
Pseudomonas aeruginosa biofilms are common in chronic wound infections and recalcitrant to treatment. Survival of cells within oxygen-limited regions in these biofilms is enabled by extracellular electron transfer (EET), whereby small redox active molecules act as electron shuttles to access distal oxidants. Here, we report that electrochemically controlling the redox state of these electron shuttles, specifically pyocyanin (PYO), can impact cell survival within anaerobic P. aeruginosa biofilms and can act synergistically with antibiotic treatment. Prior results demonstrated that under anoxic conditions, an electrode poised at sufficiently oxidizing potential (+100 mV vs Ag/AgCl) promotes EET within P. aeruginosa biofilms by re-oxidizing PYO for reuse by the cells. Here, when a reducing potential (-400 mV vs Ag/AgCl) was used to disrupt PYO redox cycling by maintaining PYO in the reduced state, we observed a 100-fold decrease in colony forming units within these biofilms compared with those exposed to electrodes poised at +100 mV vs Ag/AgCl. Phenazine-deficient Δphz* biofilms were unaffected by the potential applied to the electrode but were re-sensitized by adding PYO. The effect at -400 mV was exacerbated when biofilms were treated with sub-MICs of a range of antibiotics. Most notably, addition of the aminoglycoside gentamicin in a reductive environment almost completely eradicated wild-type biofilms but had no effect on the survival of Δphz* biofilms in the absence of phenazines. These data suggest that antibiotic treatment combined with the electrochemical disruption of PYO redox cycling, either through the toxicity of accumulated reduced PYO or the disruption of EET, or both, can lead to extensive killing. IMPORTANCE Biofilms provide a protective environment but also present challenges to the cells living within them, such as overcoming nutrient and oxygen diffusion limitations. Pseudomonas aeruginosa overcomes oxygen limitation by secreting soluble redox active phenazines, which act as electron shuttles to distal oxygen. Here, we show that electrochemically blocking the re-oxidation of one of these electron shuttles, pyocyanin, decreases cell survival within biofilms and acts synergistically with gentamicin to kill cells. Our results highlight the importance of the role that the redox cycling of electron shuttles fulfills within P. aeruginosa biofilms.
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Affiliation(s)
| | - Dianne K. Newman
- Biology and Biological Engineering and Geological and Planetary Sciences, Caltech, Pasadena, California, USA
| | - Leonard M. Tender
- Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, Washington, DC, USA
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14
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Thalhammer KO, Newman DK. A phenazine-inspired framework for identifying biological functions of microbial redox-active metabolites. Curr Opin Chem Biol 2023; 75:102320. [PMID: 37201291 PMCID: PMC10524139 DOI: 10.1016/j.cbpa.2023.102320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/12/2023] [Accepted: 04/17/2023] [Indexed: 05/20/2023]
Abstract
While the list of small molecules known to be secreted by environmental microbes continues to grow, our understanding of their in situ biological functions remains minimal. The time has come to develop a framework to parse the meaning of these "secondary metabolites," which are ecologically ubiquitous and have direct applications in medicine and biotechnology. Here, we focus on a particular subset of molecules, redox active metabolites (RAMs), and review the well-studied phenazines as archetypes of this class. We argue that efforts to characterize the chemical, physical and biological makeup of the microenvironments, wherein these molecules are produced, coupled with measurements of the molecules' basic chemical properties, will enable significant progress in understanding the precise roles of novel RAMs.
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Affiliation(s)
- Korbinian O Thalhammer
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Dianne K Newman
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
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15
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Smiley MK, Sekaran DC, Price-Whelan A, Dietrich LE. Cyanide-dependent control of terminal oxidase hybridization by Pseudomonas aeruginosa MpaR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543164. [PMID: 37398129 PMCID: PMC10312525 DOI: 10.1101/2023.05.31.543164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Pseudomonas aeruginosa is a common, biofilm-forming pathogen that exhibits complex pathways of redox metabolism. It produces four different types of terminal oxidases for aerobic respiration, and for one of these-the cbb3-type terminal oxidases-it has the capacity to produce at least 16 isoforms encoded by partially redundant operons. It also produces small-molecule virulence factors that interact with the respiratory chain, including the poison cyanide. Previous studies had indicated a role for cyanide in activating expression of an "orphan" terminal oxidase subunit gene called ccoN4 and that the product contributes to P. aeruginosa cyanide resistance, fitness in biofilms, and virulence-but the mechanisms underlying this process had not been elucidated. Here, we show that the regulatory protein MpaR, which is predicted to be a pyridoxal phosphate-binding transcription factor and is encoded just upstream of ccoN4, controls ccoN4 expression in response to endogenous cyanide. Paradoxically, we find that cyanide production is required to support CcoN4's contribution to respiration in biofilms. We identify a palindromic motif required for cyanide- and MpaR-dependent expression of ccoN4 and co-expressed, adjacent loci. We also characterize the regulatory logic of this region of the chromosome. Finally, we identify residues in the putative cofactor-binding pocket of MpaR that are required for ccoN4 expression. Together, our findings illustrate a novel scenario in which the respiratory toxin cyanide acts as a signal to control gene expression in a bacterium that produces the compound endogenously.
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Affiliation(s)
- Marina K. Smiley
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Doran C. Sekaran
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Lars E.P. Dietrich
- Department of Biological Sciences, Columbia University, New York, NY 10025
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16
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Zani ACB, Almeida ÉJRD, Furlan JPR, Pedrino M, Guazzaroni ME, Stehling EG, Andrade ARD, Reginatto V. Electrobiochemical skills of Pseudomonas aeruginosa species that produce pyocyanin or pyoverdine for glycerol oxidation in a microbial fuel cell. CHEMOSPHERE 2023:139073. [PMID: 37263512 DOI: 10.1016/j.chemosphere.2023.139073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 05/05/2023] [Accepted: 05/28/2023] [Indexed: 06/03/2023]
Abstract
Pseudomonas aeruginosa can produce pigments, which mediate external electron transfer (EET). Depending on the mediator, this species can be explored in bioelectrosystems to harvest energy or to obtain chemicals from residual organic compounds. This study has compared the performance of microbial fuel cells (MFCs) inoculated with a Pseudomonas aeruginosa isolate, namely EW603 or EW819, which produce pyocyanin and pyoverdine, respectively. The efficiency of these MFCs in glycerol, a typical residue of biodiesel production, were also compared. The MFCs exhibited different performances. The maximum voltage was 411 and 281 mV m2, the power density was 40.1 and 21.3 mW m-2, and the coulombic efficiency was 5.16 and 1.49% for MFC-EW603 and MFC-EW819, respectively. MFC-EW603 and MFC-EW819 achieved maximum current at 560 and 2200 Ω, at 141.2 and 91.3 mA m-2, respectively. When the system was operated at the respective maximum current output, MFC-EW603 consumed the total glycerol content (11 mmol L-1), and no products could be detected after 50 h. In turn, acetic and butyric acids were detected at the end of MFC-EW819 operation (75 h). The results suggested that P. aeruginosa metabolism can be steered in the MFC to generate current or microbial products depending on the pigment-producing strain and the conditions applied to the system, such as the external resistance. In addition, gene cluster pathways related to phenazine production (phzA and phzB) and other electrogenic-related genes (mexGHI-opmB) were identified in the strain genomes, supporting the findings. These results open new possibilities for using glycerol in bioelectrochemical systems.
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Affiliation(s)
- Ana Clara Bonizol Zani
- Universidade de São Paulo- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto - FFCLRP - SP. Departamento de Química, Av. Bandeirantes, 3900, CEP 14040-030, Ribeirão Preto, SP, Brazil
| | - Érica Janaina Rodrigues de Almeida
- Universidade de São Paulo- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto - FFCLRP - SP. Departamento de Química, Av. Bandeirantes, 3900, CEP 14040-030, Ribeirão Preto, SP, Brazil
| | - João Pedro Rueda Furlan
- Universidade de São Paulo - Faculdade de Ciências Farmacêuticas de Ribeirão Preto - FCFRP - SP. Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Av. Bandeirantes, 3900, CEP 14040-030, Ribeirão Preto, SP, Brazil
| | - Matheus Pedrino
- Universidade de São Paulo - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Departamento de Biologia, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-901, Brazil
| | - María-Eugenia Guazzaroni
- Universidade de São Paulo - Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Departamento de Biologia, Av. Bandeirantes 3900, Ribeirão Preto, SP, 14049-901, Brazil
| | - Eliana Guedes Stehling
- Universidade de São Paulo - Faculdade de Ciências Farmacêuticas de Ribeirão Preto - FCFRP - SP. Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Av. Bandeirantes, 3900, CEP 14040-030, Ribeirão Preto, SP, Brazil
| | - Adalgisa Rodrigues de Andrade
- Universidade de São Paulo- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto - FFCLRP - SP. Departamento de Química, Av. Bandeirantes, 3900, CEP 14040-030, Ribeirão Preto, SP, Brazil; Unesp, National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), Institute of Chemistry, P.O. Box 355, 14800-900, Araraquara, SP, Brazil
| | - Valeria Reginatto
- Universidade de São Paulo- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto - FFCLRP - SP. Departamento de Química, Av. Bandeirantes, 3900, CEP 14040-030, Ribeirão Preto, SP, Brazil.
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17
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Zhang B, Shi S, Tang R, Qiao C, Yang M, You Z, Shao S, Wu D, Yu H, Zhang J, Cao Y, Li F, Song H. Recent advances in enrichment, isolation, and bio-electrochemical activity evaluation of exoelectrogenic microorganisms. Biotechnol Adv 2023; 66:108175. [PMID: 37187358 DOI: 10.1016/j.biotechadv.2023.108175] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/10/2023] [Accepted: 05/10/2023] [Indexed: 05/17/2023]
Abstract
Exoelectrogenic microorganisms (EEMs) catalyzed the conversion of chemical energy to electrical energy via extracellular electron transfer (EET) mechanisms, which underlay diverse bio-electrochemical systems (BES) applications in clean energy development, environment and health monitoring, wearable/implantable devices powering, and sustainable chemicals production, thereby attracting increasing attentions from academic and industrial communities in the recent decades. However, knowledge of EEMs is still in its infancy as only ~100 EEMs of bacteria, archaea, and eukaryotes have been identified, motivating the screening and capture of new EEMs. This review presents a systematic summarization on EEM screening technologies in terms of enrichment, isolation, and bio-electrochemical activity evaluation. We first generalize the distribution characteristics of known EEMs, which provide a basis for EEM screening. Then, we summarize EET mechanisms and the principles underlying various technological approaches to the enrichment, isolation, and bio-electrochemical activity of EEMs, in which a comprehensive analysis of the applicability, accuracy, and efficiency of each technology is reviewed. Finally, we provide a future perspective on EEM screening and bio-electrochemical activity evaluation by focusing on (i) novel EET mechanisms for developing the next-generation EEM screening technologies, and (ii) integration of meta-omics approaches and bioinformatics analyses to explore nonculturable EEMs. This review promotes the development of advanced technologies to capture new EEMs.
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Affiliation(s)
- Baocai Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Sicheng Shi
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Rui Tang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Chunxiao Qiao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Meiyi Yang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Zixuan You
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Shulin Shao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Deguang Wu
- Department of Brewing Engineering, Moutai Institute, Luban Ave, Renhuai 564507, Guizhou, PR China
| | - Huan Yu
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Junqi Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Yingxiu Cao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Feng Li
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
| | - Hao Song
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
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18
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You Z, Li J, Wang Y, Wu D, Li F, Song H. Advances in mechanisms and engineering of electroactive biofilms. Biotechnol Adv 2023; 66:108170. [PMID: 37148984 DOI: 10.1016/j.biotechadv.2023.108170] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/22/2023] [Accepted: 05/02/2023] [Indexed: 05/08/2023]
Abstract
Electroactive biofilms (EABs) are electroactive microorganisms (EAMs) encased in conductive polymers that are secreted by EAMs and formed by the accumulation and cross-linking of extracellular polysaccharides, proteins, nucleic acids, lipids, and other components. EABs are present in the form of multicellular aggregates and play a crucial role in bioelectrochemical systems (BESs) for diverse applications, including biosensors, microbial fuel cells for renewable bioelectricity production and remediation of wastewaters, and microbial electrosynthesis of valuable chemicals. However, naturally occurred EABs are severely limited owing to their low electrical conductivity that seriously restrict the electron transfer efficiency and practical applications. In the recent decade, synthetic biology strategies have been adopted to elucidate the regulatory mechanisms of EABs, and to enhance the formation and electrical conductivity of EABs. Based on the formation of EABs and extracellular electron transfer (EET) mechanisms, the synthetic biology-based engineering strategies of EABs are summarized and reviewed as follows: (i) Engineering the structural components of EABs, including strengthening the synthesis and secretion of structural elements such as polysaccharides, eDNA, and structural proteins, to improve the formation of biofilms; (ii) Enhancing the electron transfer efficiency of EAMs, including optimizing the distribution of c-type cytochromes and conducting nanowire assembly to promote contact-based EET, and enhancing electron shuttles' biosynthesis and secretion to promote shuttle-mediated EET; (iii) Incorporating intracellular signaling molecules in EAMs, including quorum sensing systems, secondary messenger systems, and global regulatory systems, to increase the electron transfer flux in EABs. This review lays a foundation for the design and construction of EABs for diverse BES applications.
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Affiliation(s)
- Zixuan You
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Jianxun Li
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100093, China
| | - Yuxuan Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Deguang Wu
- Department of Brewing Engineering, Moutai Institute, Luban Ave, Renhuai 564507, Guizhou, PR China
| | - Feng Li
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
| | - Hao Song
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
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19
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Ciemniecki JA, Newman DK. NADH dehydrogenases are the predominant phenazine reductases in the electron transport chain of Pseudomonas aeruginosa. Mol Microbiol 2023; 119:560-573. [PMID: 36840394 PMCID: PMC11129870 DOI: 10.1111/mmi.15049] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/15/2023] [Accepted: 02/21/2023] [Indexed: 02/26/2023]
Abstract
Phenazines are redox-active secondary metabolites produced by diverse bacteria including the opportunistic pathogen Pseudomonas aeruginosa. Extracellular electron transfer via phenazines enhances anaerobic survival by serving as an electron sink for glucose catabolism. However, the specific phenazine reductase(s) used to support this catabolism are unknown. Because electron transport chain components have been previously implicated in phenazine reduction, we sought to determine which of them possess phenazine reductase activity. We show that phenazine-1-carboxamide (PCN) and pyocyanin (PYO) are reduced at the highest rate by cells and are localized to the cell envelope while reduced. Using a coupled genetic and biochemical approach, we show that phenazine reductase activity in membrane fractions is attributable to the three NADH dehydrogenases present in P. aeruginosa and that their order of phenazine reductase activity is Nqr > Nuo > Ndh. In mutants possessing only one functional NADH dehydrogenase, whole cell reduction rates of PCN, but not PYO, recapitulate the pattern of biochemical results, implying that PYO reduction is predominantly occurring in the cytosol. Lastly, we show that ubiquinone rapidly and non-enzymatically oxidizes reduced phenazines, demonstrating that phenazines have the capability to serve in a redox loop between the NADH and ubiquinone pools, a finding that carries bioenergetic implications.
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Affiliation(s)
- John A Ciemniecki
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Dianne K Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
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20
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Gupta D, Chen K, Elliott SJ, Nayak DD. MmcA is an electron conduit that facilitates both intracellular and extracellular electron transport in Methanosarcina acetivorans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.20.537704. [PMID: 37131651 PMCID: PMC10153276 DOI: 10.1101/2023.04.20.537704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Methanogens are a diverse group of Archaea that couple energy conservation to the production of methane gas. While most methanogens have no alternate mode of energy conservation, strains like Methanosarcina acetivorans are known to also conserve energy by dissimilatory metal reduction (DSMR) in the presence of soluble ferric iron or iron-containing minerals. The ecological ramifications of energy conservation decoupled from methane production in methanogens are substantial, yet the molecular details are poorly understood. In this work, we conducted in vitro and in vivo studies with a multiheme c-type cytochrome (MHC), called MmcA, to establish its role during methanogenesis and DSMR in M. acetivorans. MmcA purified from M. acetivorans can donate electrons to methanophenazine, a membrane-bound electron carrier, to facilitate methanogenesis. In addition, MmcA can also reduce Fe(III) and the humic acid analog anthraquinone-2,6-disulfonate (AQDS) during DSMR. Furthermore, mutants lacking mmcA have slower Fe(III) reduction rates. The redox reactivities of MmcA are consistent with the electrochemical data where MmcA displays reversible redox features ranging from -100 to -450 mV versus SHE. MmcA is prevalent in members of the Order Methanosarcinales but does not belong to a known family of MHCs linked to extracellular electron transfer, bioinformatically, and instead forms a distinct clade that is closely related to octaheme tetrathionate reductases. Taken together, this study shows that MmcA is widespread in methanogens with cytochromes where it acts as an electron conduit to support a variety of energy conservation strategies that extend beyond methanogenesis.
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Affiliation(s)
- Dinesh Gupta
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Keying Chen
- Department of Chemistry, Boston University, Boston, MA, USA
| | | | - Dipti D. Nayak
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
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21
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Alatawneh N, Meijler MM. Unraveling the Antibacterial and Iron Chelating Activity of
N
‐Oxide Hydroxy‐Phenazine natural Products and Synthetic Analogs against
Staphylococcus Aureus. Isr J Chem 2023. [DOI: 10.1002/ijch.202200112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Affiliation(s)
- Nadeem Alatawneh
- Department of Chemistry and The National Institute for Biotechnology in the Negev Ben-Gurion University of the Negev Be'er Sheva 84105 Israel
| | - Michael M. Meijler
- Department of Chemistry and The National Institute for Biotechnology in the Negev Ben-Gurion University of the Negev Be'er Sheva 84105 Israel
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22
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McRose D, Li J, Newman D. The chemical ecology of coumarins and phenazines affects iron acquisition by pseudomonads. Proc Natl Acad Sci U S A 2023; 120:e2217951120. [PMID: 36996105 PMCID: PMC10083548 DOI: 10.1073/pnas.2217951120] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 02/27/2023] [Indexed: 03/31/2023] Open
Abstract
Secondary metabolites are important facilitators of plant-microbe interactions in the rhizosphere, contributing to communication, competition, and nutrient acquisition. However, at first glance, the rhizosphere seems full of metabolites with overlapping functions, and we have a limited understanding of basic principles governing metabolite use. Increasing access to the essential nutrient iron is one important, but seemingly redundant role performed by both plant and microbial Redox-Active Metabolites (RAMs). We used coumarins, RAMs made by the model plant Arabidopsis thaliana, and phenazines, RAMs made by soil-dwelling pseudomonads, to ask whether plant and microbial RAMs might each have distinct functions under different environmental conditions. We show that variations in oxygen and pH lead to predictable differences in the capacity of coumarins vs phenazines to increase the growth of iron-limited pseudomonads and that these effects depend on whether pseudomonads are grown on glucose, succinate, or pyruvate: carbon sources commonly found in root exudates. Our results are explained by the chemical reactivities of these metabolites and the redox state of phenazines as altered by microbial metabolism. This work shows that variations in the chemical microenvironment can profoundly affect secondary metabolite function and suggests plants may tune the utility of microbial secondary metabolites by altering the carbon released in root exudates. Together, these findings suggest that RAM diversity may be less overwhelming when viewed through a chemical ecological lens: Distinct molecules can be expected to be more or less important to certain ecosystem functions, such as iron acquisition, depending on the local chemical microenvironments in which they reside.
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Affiliation(s)
- Darcy L. McRose
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA91125
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA91125
| | - Jinyang Li
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA91125
| | - Dianne K. Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA91125
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA91125
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Franco A, Elbahnasy M, Rosenbaum MA. Screening of natural phenazine producers for electroactivity in bioelectrochemical systems. Microb Biotechnol 2023; 16:579-594. [PMID: 36571174 PMCID: PMC9948232 DOI: 10.1111/1751-7915.14199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 12/05/2022] [Accepted: 12/07/2022] [Indexed: 12/27/2022] Open
Abstract
Mediated extracellular electron transfer (EET) might be a great vehicle to connect microbial bioprocesses with electrochemical control in stirred-tank bioreactors. However, mediated electron transfer to date is not only much less efficient but also much less studied than microbial direct electron transfer to an anode. For example, despite the widespread capacity of pseudomonads to produce phenazine natural products, only Pseudomonas aeruginosa has been studied for its use of phenazines in bioelectrochemical applications. To provide a deeper understanding of the ecological potential for the bioelectrochemical exploitation of phenazines, we here investigated the potential electroactivity of over 100 putative diverse native phenazine producers and the performance within bioelectrochemical systems. Five species from the genera Pseudomonas, Streptomyces, Nocardiopsis, Brevibacterium and Burkholderia were identified as new electroactive bacteria. Electron discharge to the anode and electric current production correlated with the phenazine synthesis of Pseudomonas chlororaphis subsp. aurantiaca. Phenazine-1-carboxylic acid was the dominant molecule with a concentration of 86.1 μg/ml mediating an anodic current of 15.1 μA/cm2 . On the other hand, Nocardiopsis chromatogenes used a wider range of phenazines at low concentrations and likely yet-unknown redox compounds to mediate EET, achieving an anodic current of 9.5 μA/cm2 . Elucidating the energetic and metabolic usage of phenazines in these and other species might contribute to improving electron discharge and respiration. In the long run, this may enhance oxygen-limited bioproduction of value-added compounds based on mediated EET mechanisms.
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Affiliation(s)
- Angel Franco
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Jena, Germany
| | - Mahmoud Elbahnasy
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Jena, Germany.,Faculty of Biological Sciences, Friedrich Schiller University (FSU), Jena, Germany
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Jena, Germany.,Faculty of Biological Sciences, Friedrich Schiller University (FSU), Jena, Germany
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Emergence of Small Colony Variants Is an Adaptive Strategy Used by Pseudomonas aeruginosa to Mitigate the Effects of Redox Imbalance. mSphere 2023; 8:e0005723. [PMID: 36853007 PMCID: PMC10117050 DOI: 10.1128/msphere.00057-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
The ability to generate a subpopulation of small colony variants (SCVs) is a conserved feature of Pseudomonas aeruginosa and could represent a key adaptive strategy to colonize and persist in multiple niches. However, very little is known about the role of the SCV phenotype, the conditions that promote its emergence, and its possible involvement in an adaptive strategy. In the present work, we investigated the in vitro selective conditions promoting the emergence of SCVs from the prototypical strain PA14, which readily forms SCVs in nonagitated standing cultures. We found that O2 limitation, which causes a redox imbalance, is the main factor selecting for the SCV phenotype, which promotes survival of the population via formation of a biofilm at the air-liquid interface to access the electron acceptor. When this selective pressure is relieved by aeration or supplementation of an alternative electron acceptor, SCVs are barely detectable. We also observed that SCV emergence contributes to redox rebalancing, suggesting that it is involved in an adaptive strategy. We conclude that selection for the SCV phenotype is an adaptive solution adopted by P. aeruginosa to access poorly available O2. IMPORTANCE The bacterium Pseudomonas aeruginosa is an opportunistic pathogen that thrives in many environments. It poses a significant health concern, notably because it is a causative agent of nosocomial infections and the most prevalent pathogen found in the lungs of people with cystic fibrosis. In infected hosts, its persistence is often related to the emergence of an alternative phenotype known as small colony variant (SCV). Identification of conditions selecting for the SCV phenotype contributes to knowledge regarding adaptive mechanisms exploited by P. aeruginosa to survive in multiple niches and persist during infections. Hindering this adaptation strategy could help control persistent P. aeruginosa infections.
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Evans CR, Smiley MK, Thio SA, Wei M, Price-Whelan A, Min W, Dietrich LE. Spatial heterogeneity in biofilm metabolism elicited by local control of phenazine methylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528762. [PMID: 36824979 PMCID: PMC9949047 DOI: 10.1101/2023.02.15.528762] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Within biofilms, gradients of electron acceptors such as oxygen stimulate the formation of physiological subpopulations. This heterogeneity can enable cross-feeding and promote drug resilience, features of the multicellular lifestyle that make biofilm-based infections difficult to treat. The pathogenic bacterium Pseudomonas aeruginosa produces pigments called phenazines that can support metabolic activity in hypoxic/anoxic biofilm subzones, but these compounds also include methylated derivatives that are toxic to their producer under some conditions. Here, we uncover roles for the global regulators RpoS and Hfq/Crc in controlling the beneficial and detrimental effects of methylated phenazines in biofilms. Our results indicate that RpoS controls phenazine methylation by modulating activity of the carbon catabolite repression pathway, in which the Hfq/Crc complex inhibits translation of the phenazine methyltransferase PhzM. We find that RpoS indirectly inhibits expression of CrcZ, a small RNA that binds to and sequesters Hfq/Crc, specifically in the oxic subzone of P. aeruginosa biofilms. Deletion of rpoS or crc therefore leads to overproduction of methylated phenazines, which we show leads to increased metabolic activity-an apparent beneficial effect-in hypoxic/anoxic subpopulations within biofilms. However, we also find that biofilms lacking Crc show increased sensitivity to an exogenously added methylated phenazine, indicating that the increased metabolic activity in this mutant comes at a cost. Together, these results suggest that complex regulation of PhzM allows P. aeruginosa to simultaneously exploit the benefits and limit the toxic effects of methylated phenazines.
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Affiliation(s)
| | - Marina K. Smiley
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Sean Asahara Thio
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Mian Wei
- Department of Chemistry, Columbia University, New York, NY 10025
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Wei Min
- Department of Chemistry, Columbia University, New York, NY 10025
| | - Lars E.P. Dietrich
- Department of Biological Sciences, Columbia University, New York, NY 10025
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26
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Smith HB, Lee K, Stevenson DM, Amador-Noguez D, Sauer JD. Listeria monocytogenes requires DHNA-dependent intracellular redox homeostasis facilitated by Ndh2 for survival and virulence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.524026. [PMID: 36711537 PMCID: PMC9882099 DOI: 10.1101/2023.01.13.524026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Listeria monocytogenes is a remarkably well-adapted facultative intracellular pathogen that can thrive in a wide range of ecological niches. L. monocytogenes maximizes its ability to generate energy from diverse carbon sources using a respiro-fermentative metabolism that can function under both aerobic and anaerobic conditions. Cellular respiration maintains redox homeostasis by regenerating NAD + while also generating a proton motive force (PMF). The end products of the menaquinone (MK) biosynthesis pathway are essential to drive both aerobic and anaerobic cellular respiration. We previously demonstrated that intermediates in the MK biosynthesis pathway, notably 1,4-dihydroxy-2-naphthoate (DHNA), are required for the survival and virulence of L. monocytogenes independent of their role in respiration. Furthermore, we found that restoration of NAD + /NADH ratio through expression of water-forming NADH oxidase (NOX) could rescue phenotypes associated with DHNA deficiency. Here we extend these findings to demonstrate that endogenous production or direct supplementation of DHNA restored both the cellular redox homeostasis and metabolic output of fermentation in L. monocytogenes . Further, exogenous supplementation of DHNA rescues the in vitro growth and ex vivo virulence of L. monocytogenes DHNA-deficient mutants. Finally, we demonstrate that exogenous DHNA restores redox balance in L. monocytogenes specifically through the recently annotated NADH dehydrogenase Ndh2, independent of the extracellular electron transport (EET) pathway. These data suggest that the production of DHNA may represent an additional layer of metabolic adaptability by L. monocytogenes to drive energy metabolism in the absence of respiration-favorable conditions.
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Affiliation(s)
- Hans B. Smith
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, United States of America
| | - Kijeong Lee
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, United States of America
| | - David M. Stevenson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, United States of America
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, United States of America
| | - John-Demian Sauer
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, 53706, United States of America
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Pyocyanin and 1-Hydroxyphenazine Promote Anaerobic Killing of Pseudomonas aeruginosa via Single-Electron Transfer with Ferrous Iron. Microbiol Spectr 2022; 10:e0231222. [PMID: 36321913 PMCID: PMC9769500 DOI: 10.1128/spectrum.02312-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Previously, it was reported that natural phenazines are able to support the anaerobic survival of Pseudomonas aeruginosa PA14 cells via electron shuttling, with electrodes poised as the terminal oxidants (Y. Wang, S. E. Kern, and D. K. Newman, J Bacteriol 192:365-369, 2010, https://doi.org/10.1128/JB.01188-09). The present study shows that both pyocyanin (PYO) and 1-hydroxyphenazine (1-OHPHZ) promoted the anaerobic killing of PA14 Δphz cells presumably via a single-electron transfer reaction with ferrous iron. However, phenazine-1-carboxylic acid (PCA) did not affect anaerobic survival in the presence of ferrous iron. Anaerobic cell death was alleviated by the addition of antioxidant compounds, which inhibit electron transfer via DNA damage. Neither superoxide dismutase (SOD) nor catalase was able to alleviate P. aeruginosa cell death, ruling out the possibility of reactive oxygen species (ROS)-induced killing. Further, the phenazine degradation profile and the redox state-associated color changes suggested that phenazine radical intermediates are likely generated by single-electron transfer. In this study, we showed that the phenazines 1-OHPHZ and PYO anaerobically killed the cell via single-electron transfer with ferrous iron and that the killing might have resulted from phenazine radicals. IMPORTANCE Pseudomonas aeruginosa is an opportunistic human pathogen which infects patients with burns, immunocompromised individuals, and in particular, the mucus that accumulates on the surface of the lung in cystic fibrosis (CF) patients. Phenazines as redox-active small molecules have been reported as important compounds for the control of cellular functions and virulence as well as anaerobic survival via electron shuttles. We show that both pyocyanin (PYO) and 1-hydroxyphenazine (1-OHPHZ) generate phenazine radical intermediates via presumably single-electron transfer reaction with ferrous iron, leading to the anaerobic killing of Pseudomonas cells. The recA mutant defect in the DNA repair system was more sensitive to anaerobic conditions. Our results collectively suggest that both phenazines anaerobically kill cells via DNA damage during electron transfer with iron.
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Membrane-Binding Biomolecules Influence the Rate of Vesicle Exchange between Bacteria. Appl Environ Microbiol 2022; 88:e0134622. [PMID: 36342184 PMCID: PMC9746307 DOI: 10.1128/aem.01346-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The exchange of bacterial extracellular vesicles facilitates molecular exchange between cells, including the horizontal transfer of genetic material. Given the implications of such transfer events on cell physiology and adaptation, some bacterial cells have likely evolved mechanisms to regulate vesicle exchange. Past work has identified mechanisms that influence the formation of extracellular vesicles, including the production of small molecules that modulate membrane structure; however, whether these mechanisms also modulate vesicle uptake and have an overall impact on the rate of vesicle exchange is unknown. Here, we show that membrane-binding molecules produced by microbes influence both the formation and uptake of extracellular vesicles and have the overall impact of increasing the vesicle exchange rate within a bacterial coculture. In effect, production of compounds that increase vesicle exchange rates encourage gene exchange between neighboring cells. The ability of several membrane-binding compounds to increase vesicle exchange was demonstrated. Three of these compounds, nisin, colistin, and polymyxin B, are antimicrobial peptides added at sub-inhibitory concentrations. These results suggest that a potential function of exogenous compounds that bind to membranes may be the regulation of vesicle exchange between cells. IMPORTANCE The exchange of bacterial extracellular vesicles is one route of gene transfer between bacteria, although it was unclear if bacteria developed strategies to modulate the rate of gene transfer within vesicles. In eukaryotes, there are many examples of specialized molecules that have evolved to facilitate the production, loading, and uptake of vesicles. Recent work with bacteria has shown that some small molecules influence membrane curvature and induce vesicle formation. Here, we show that similar compounds facilitate vesicle uptake, thereby increasing the overall rate of vesicle exchange within bacterial populations. The addition of membrane-binding compounds, several of them antibiotics at subinhibitory concentrations, to a bacterial coculture increased the rate of horizontal gene transfer via vesicle exchange.
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29
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Nie H, Liu X, Dang Y, Sun D. Early activated quorum sensing enhanced a nosZ-deficient strain of Pseudomonas aeruginosa for stably recovering nitrous oxide from incineration leachate in microbial electrolysis cell. BIORESOURCE TECHNOLOGY 2022; 360:127394. [PMID: 35640816 DOI: 10.1016/j.biortech.2022.127394] [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: 04/15/2022] [Revised: 05/21/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
In this study, a quorum sensing (QS) signal molecule, 3-oxo-C12-HSL, was supplied into ΔnosZ Pseudomonas microbial electrolysis cell system for strengthening the N2O recovery from incineration leachate. The resistance for high nitrite loading was strongly improved with nitrite removal efficiency of 80.35% compared to 67.07% from the control on day 13 due to the increasing biomass through early activated QS. Higher N2O proportion in biogas (85.85% on average) was achieved in the QS early activated reactor, which indicated the better potential for N2O recovery. Bacterial community analysis showed the purity of ΔnosZ strain with the abundance of 100% in the anode chamber at the end of the operation. This was plausibly related to the increased synthesis of phenazine derivatives by the early activated QS system. These results show a more promising way for N2O recovery by a single engineering bacteria from the high nitrogen contained actual wastewater.
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Affiliation(s)
- Hanbing Nie
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Xinying Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yan Dang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Dezhi Sun
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
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30
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Kelly KP, Borsetti H, Wenzler ME, Ustione A, Kim K, Christov PP, Ramirez B, Bauer JA, Piston DW, Johnson CH, Sulikowski GA. Screen for Small-Molecule Modulators of Circadian Rhythms Reveals Phenazine as a Redox-State Modifying Clockwork Tuner. ACS Chem Biol 2022; 17:1658-1664. [PMID: 35679588 PMCID: PMC9398883 DOI: 10.1021/acschembio.2c00240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A high-throughput cell-based screen identified redox-active small molecules that produce a period lengthening of the circadian rhythm. The strongest period lengthening phenotype was induced by a phenazine carboxamide (VU661). Comparison to two isomeric benzquinoline carboxamides (VU673 and VU164) shows the activity is associated with the redox modulating phenazine functionality. Furthermore, ex vivo cell analysis using optical redox ratio measurements shows the period lengthening phenotype to be associated with a shift to the NAD/FAD oxidation state of nicotinamide and flavine coenzymes.
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Affiliation(s)
- Kevin P Kelly
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Hugo Borsetti
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Marta E Wenzler
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Alessandro Ustione
- Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Kwangho Kim
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Plamen P Christov
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Bianca Ramirez
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Joshua A Bauer
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - David W Piston
- Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Carl Hirschie Johnson
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Gary A Sulikowski
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
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31
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A 1D Model for a Single Chamber Microbial Fuel cell. Chem Eng Res Des 2022. [DOI: 10.1016/j.cherd.2022.06.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Complete genome sequence of Pseudomonas stutzeri S116 owning bifunctional catalysis provides insights into affecting performance of microbial fuel cells. BMC Microbiol 2022; 22:137. [PMID: 35590268 PMCID: PMC9118636 DOI: 10.1186/s12866-022-02552-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 05/03/2022] [Indexed: 12/03/2022] Open
Abstract
Background Pseudomonas stutzeri S116 is a sulfur-oxidizing bacteria isolated from marine sludge. It exhibited excellent electricity generation as bioanode and biocathode applied in microbial fuel cells (MFCs). Complete genome sequencing of P. stutzeri and cyclic voltammetry method were performed to reveal its mechanism in microbial fuel cells system. Results This study indicated that the MFCs generated a maximum output voltage of 254.2 mV and 226.0 mV, and maximum power density of 765 mW/m2 and 656.6 mW/m2 respectively. Complete genome sequencing of P. stutzeri S116 was performed to indicate that most function genes showed high similarities with P. stutzeri, and its primary annotations were associated with energy production and conversion (6.84%), amino acid transport and metabolism (6.82%) and inorganic ion transport and metabolism (6.77%). Homology of 36 genes involved in oxidative phosphorylation was detected, which suggests the strain S116 possesses an integrated electron transport chain. Additionally, many genes encoding pilus-assembly proteins and redox mediators (riboflavin and phenazine) were detected in the databases. Thiosulfate oxidization and dissimilatory nitrate reduction were annotated in the sulfur metabolism pathway and nitrogen metabolism pathway, respectively. Gene function analysis and cyclic voltammetry indicated that P. stutzeri probably possesses cellular machinery such as cytochrome c and redox mediators and can perform extracellular electron transfer and produce electricity in MFCs. Conclusion The redox mediators secreted by P. stutzeri S116 were probably responsible for performance of MFCs. The critical genes and metabolic pathways involved in thiosulfate oxide and nitrate reduction were detected, which indicated that the strain can treat wastewater containing sulfide and nitrite efficiently. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02552-8.
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Suri M, Mohamed Z, Bint E Naser SF, Mao X, Chen P, Daniel S, Hanrath T. Bioelectronic Platform to Investigate Charge Transfer between Photoexcited Quantum Dots and Microbial Outer Membranes. ACS APPLIED MATERIALS & INTERFACES 2022; 14:15799-15810. [PMID: 35344337 DOI: 10.1021/acsami.1c25032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Photosynthetic semiconductor biohybrids (PSBs) convert light energy to chemical energy through photo-driven charge transfer from nanocrystals to microorganisms that perform bioreactions of interest. Initial proof-of-concept PSB studies with an emphasis on enhanced CO2 conversion have been encouraging; however, bringing the broad prospects of PSBs to fruition is contingent on establishing a firm fundamental understanding of underlying interfacial charge transfer processes. We introduce a bioelectronic platform that reduces the complexity of PSBs by focusing explicitly on interactions between colloidal quantum dots (QDs), microbial outer membranes, and native, small-molecule redox mediators. Our model platform employs a standard three-electrode electrochemical cell with supported outer membranes of Pseudomonas aeruginosa, pyocyanin redox mediators, and semiconducting CdSe QDs dispersed in an aqueous electrolyte. We present a comprehensive electrochemical analysis of this platform via electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and chronoamperometry (CA). EIS reveals the formation and electronic properties of supported outer membrane films. CV reveals the electrochemically active surface area of P. aeruginosa outer membranes and that pyocyanin is the sole species that performs redox with these outer membranes under sweeping applied potential. CA demonstrates that photoexcited charge transfer in this system is driven by the reduction of pyocyanin at the QD surface followed by diffusion of reduced pyocyanin through the outer membrane. The broad applicability of this platform across many bacterial species, QD architectures, and controlled environmental conditions affords the possibility to define design principles for future PSB systems to synergistically integrate concurrent advances in genetically engineered organisms and inorganic nanomaterials.
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Affiliation(s)
- Mokshin Suri
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Zeinab Mohamed
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Samavi Farnush Bint E Naser
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Xianwen Mao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Peng Chen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Susan Daniel
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Tobias Hanrath
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
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34
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Peng W, Li H, Zhao X, Shao B, Zhu K. Pyocyanin Modulates Gastrointestinal Transformation and Microbiota. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:2722-2732. [PMID: 35171599 DOI: 10.1021/acs.jafc.1c07726] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Phenazines are ubiquitously produced by Pseudomonas spp. in the environment and are widely used in agriculture and clinical therapies, making their accumulation through the food chain cause potential risks to human health. Here, we utilized pyocyanin (PYO) as a representative to study the effects of phenazines on digestive tracts. Pharmacokinetic analysis showed that PYO exhibited low systemic exposure, slow elimination, and low accumulation in both rat and pig models. PYO was subsequently found to induce intestinal microbiota dysbiosis, destroy the mucus layer and physical barrier, and even promote gut vascular barrier (GVB) impairment, consequently increasing the gut permeability. Additionally, integral and metabolomic analyses of the liver demonstrated that PYO induced liver inflammation and metabolic disorders. The metabolic analysis further confirmed that all of the metabolites of PYO retain the nitrogen-containing tricyclic structural skeleton of phenazines, which was the core bioactivity of phenazine compounds. These findings elucidated that PYO could be metabolized by animals. Meanwhile, high levels of PYO could induce intestinal barrier impairment and liver damage, suggesting that we should be alert to the accumulation of phenazines.
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Affiliation(s)
- Wenjing Peng
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Hui Li
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing 100013, China
| | - Xiaole Zhao
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Bing Shao
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing 100013, China
| | - Kui Zhu
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
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Tibbits G, Mohamed A, Call DR, Beyenal H. Rapid differentiation of antibiotic-susceptible and -resistant bacteria through mediated extracellular electron transfer. Biosens Bioelectron 2022; 197:113754. [PMID: 34773749 DOI: 10.1016/j.bios.2021.113754] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/18/2021] [Accepted: 10/29/2021] [Indexed: 11/02/2022]
Abstract
Conventional methods for testing antibiotic susceptibility rely on bacterial growth on agar plates (diffusion assays) or in liquid culture (microdilution assays). These time-consuming assays use population growth as a proxy for cellular respiration. Herein we propose to use mediated extracellular electron transfer as a rapid and direct method to classify antibiotic-susceptible and -resistant bacteria. We tested antibiotics with diverse mechanisms of action (ciprofloxacin, imipenem, oxacillin, or tobramycin) with four important nosocomial pathogens (Acinetobacter baumannii, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) by adding the bacterial culture to a custom-designed electrochemical cell with a glassy-carbon electrode and growth media supplemented with a soluble electron transfer mediator, phenazine methosulfate (PMS). During cell respiration, liberated electrons reduce PMS, which is then oxidized on the electrode surface, and current is recorded. Using this novel approach, we were able to consistently classify strains as antibiotic-resistant or -susceptible in <90 min for methodology development and <150 min for blinded tests.
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Affiliation(s)
- Gretchen Tibbits
- The Gene and Linda Voil and School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - Abdelrhman Mohamed
- The Gene and Linda Voil and School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - Douglas R Call
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Haluk Beyenal
- The Gene and Linda Voil and School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA.
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Yue H, Miller AL, Khetrapal V, Jayaseker V, Wright S, Du L. Biosynthesis, regulation, and engineering of natural products from Lysobacter. Nat Prod Rep 2022; 39:842-874. [PMID: 35067688 DOI: 10.1039/d1np00063b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Covering: up to August 2021Lysobacter is a genus of Gram-negative bacteria that was classified in 1987. Several Lysobacter species are emerging as new biocontrol agents for crop protection in agriculture. Lysobacter are prolific producers of new bioactive natural products that are largely underexplored. So far, several classes of structurally interesting and biologically active natural products have been isolated from Lysobacter. This article reviews the progress in Lysobacter natural product research over the past ten years, including molecular mechanisms for biosynthesis, regulation and mode of action, genome mining of cryptic biosynthetic gene clusters, and metabolic engineering using synthetic biology tools.
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Affiliation(s)
- Huan Yue
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Amanda Lynn Miller
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Vimmy Khetrapal
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Vishakha Jayaseker
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Stephen Wright
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Liangcheng Du
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
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37
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Thermodynamic controls on rates of iron oxide reduction by extracellular electron shuttles. Proc Natl Acad Sci U S A 2022; 119:2115629119. [PMID: 35017303 PMCID: PMC8784112 DOI: 10.1073/pnas.2115629119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2021] [Indexed: 11/18/2022] Open
Abstract
Anaerobic microbial respiration in suboxic and anoxic environments often involves particulate ferric iron (oxyhydr-)oxides as terminal electron acceptors. To ensure efficient respiration, a widespread strategy among iron-reducing microorganisms is the use of extracellular electron shuttles (EES) that transfer two electrons from the microbial cell to the iron oxide surface. Yet, a fundamental understanding of how EES-oxide redox thermodynamics affect rates of iron oxide reduction remains elusive. Attempts to rationalize these rates for different EES, solution pH, and iron oxides on the basis of the underlying reaction free energy of the two-electron transfer were unsuccessful. Here, we demonstrate that broadly varying reduction rates determined in this work for different iron oxides and EES at varying solution chemistry as well as previously published data can be reconciled when these rates are instead related to the free energy of the less exergonic (or even endergonic) first of the two electron transfers from the fully, two-electron reduced EES to ferric iron oxide. We show how free energy relationships aid in identifying controls on microbial iron oxide reduction by EES, thereby advancing a more fundamental understanding of anaerobic respiration using iron oxides.
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38
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Transcriptional Profiling of Pseudomonas aeruginosa Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:303-323. [DOI: 10.1007/978-3-031-08491-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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39
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Dong Y, Sui M, Wang X, Zhang P, Jiang Y, Wu J. Responses of electroactive biofilms to chronic chlorine exposure: Insights from the composition and spatial structure of extracellular polymeric substances. Bioelectrochemistry 2021; 142:107894. [PMID: 34371350 PMCID: PMC8492042 DOI: 10.1016/j.bioelechem.2021.107894] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 11/29/2022]
Abstract
Extensive amounts of chlorine disinfectants have been applied to wastewater system since the outbreak of coronavirus disease 2019 (COVID-19), which inevitably affects the pollutant degradation via interfering with electron transfer mediated by electroactive bacteria. Herein, the response of electroactive biofilm (EAB) to chronic chlorine exposure was investigated. Results showed the EAB formed without exposure (EAB-0) exhibited a 53% and 123% higher current output than that formed with 0.1 mg L-1 (EAB-0.1) and 0.5 mg L-1 (EAB-0.5) chlorine, respectively. The chronic chlorine exposure of EAB boosted the contents of extracellular polymeric substances (EPS) in EAB-0.1 and EAB-0.5 by over secretion of extracellular polysaccharides. The EAB-0.1 and EAB-0.5 also presented lower electron exchange capacities (EECs) of EPS, coincided with reduced relative abundance of Geobacter from 61% in EAB-0 to 52% in EAB-0.5. This study provided new insights into the application of engineered EAB for wastewater treatment in a disinfection environment.
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Affiliation(s)
- Yue Dong
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Mingrui Sui
- College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China.
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria and Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Peng Zhang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Yiying Jiang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Jianyu Wu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
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40
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McCuskey SR, Chatsirisupachai J, Zeglio E, Parlak O, Panoy P, Herland A, Bazan GC, Nguyen TQ. Current Progress of Interfacing Organic Semiconducting Materials with Bacteria. Chem Rev 2021; 122:4791-4825. [PMID: 34714064 DOI: 10.1021/acs.chemrev.1c00487] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microbial bioelectronics require interfacing microorganisms with electrodes. The resulting abiotic/biotic platforms provide the basis of a range of technologies, including energy conversion and diagnostic assays. Organic semiconductors (OSCs) provide a unique strategy to modulate the interfaces between microbial systems and external electrodes, thereby improving the performance of these incipient technologies. In this review, we explore recent progress in the field on how OSCs, and related materials capable of charge transport, are being used within the context of microbial systems, and more specifically bacteria. We begin by examining the electrochemical communication modes in bacteria and the biological basis for charge transport. Different types of synthetic organic materials that have been designed and synthesized for interfacing and interrogating bacteria are discussed next, followed by the most commonly used characterization techniques for evaluating transport in microbial, synthetic, and hybrid systems. A range of applications is subsequently examined, including biological sensors and energy conversion systems. The review concludes by summarizing what has been accomplished so far and suggests future design approaches for OSC bioelectronics materials and technologies that hybridize characteristic properties of microbial and OSC systems.
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Affiliation(s)
- Samantha R McCuskey
- Department of Chemistry, National University of Singapore, Singapore 119077, Singapore
| | - Jirat Chatsirisupachai
- Center for Polymers and Organic Solids & Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Erica Zeglio
- Division of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm 17177, Sweden
| | - Onur Parlak
- Dermatology and Venereology Division, Department of Medicine(Solna), Karolinska Institute, Stockholm 17177, Sweden.,AIMES Center of Integrated Medical and Engineering Sciences, Department of Neuroscience, Karolinska Institute, Stockholm 17177, Sweden
| | - Patchareepond Panoy
- Center for Polymers and Organic Solids & Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Anna Herland
- Division of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm 17177, Sweden.,AIMES Center of Integrated Medical and Engineering Sciences, Department of Neuroscience, Karolinska Institute, Stockholm 17177, Sweden
| | - Guillermo C Bazan
- Department of Chemistry, National University of Singapore, Singapore 119077, Singapore
| | - Thuc-Quyen Nguyen
- Center for Polymers and Organic Solids & Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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41
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Computationally designed pyocyanin demethylase acts synergistically with tobramycin to kill recalcitrant Pseudomonas aeruginosa biofilms. Proc Natl Acad Sci U S A 2021; 118:2022012118. [PMID: 33723058 DOI: 10.1073/pnas.2022012118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen that develops difficult-to-treat biofilms in immunocompromised individuals, cystic fibrosis patients, and in chronic wounds. P. aeruginosa has an arsenal of physiological attributes that enable it to evade standard antibiotic treatments, particularly in the context of biofilms where it grows slowly and becomes tolerant to many drugs. One of its survival strategies involves the production of the redox-active phenazine, pyocyanin, which promotes biofilm development. We previously identified an enzyme, PodA, that demethylated pyocyanin and disrupted P. aeruginosa biofilm development in vitro. Here, we asked if this protein could be used as a potential therapeutic for P. aeruginosa infections together with tobramycin, an antibiotic typically used in the clinic. A major roadblock to answering this question was the poor yield and stability of wild-type PodA purified from standard Escherichia coli overexpression systems. We hypothesized that the insufficient yields were due to poor packing within PodA's obligatory homotrimeric interfaces. We therefore applied the protein design algorithm, AffiLib, to optimize the symmetric core of this interface, resulting in a design that incorporated five mutations leading to a 20-fold increase in protein yield from heterologous expression and purification and a substantial increase in stability to environmental conditions. The addition of the designed PodA with tobramycin led to increased killing of P. aeruginosa cultures under oxic and hypoxic conditions in both the planktonic and biofilm states. This study highlights the potential for targeting extracellular metabolites to assist the control of P. aeruginosa biofilms that tolerate conventional antibiotic treatment.
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42
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Nie H, Dang Y, Yan H, Sun D, Holmes DE. Enhanced recovery of nitrous oxide from incineration leachate in a microbial electrolysis cell inoculated with a nosZ-deficient strain of Pseudomonas aeruginosa. BIORESOURCE TECHNOLOGY 2021; 333:125082. [PMID: 33878502 DOI: 10.1016/j.biortech.2021.125082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/22/2021] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
High concentrations of nitrous oxide were recovered from partial nitrification treated leachate in a microbial electrolysis cell (MEC) inoculated with a nosZ-deficient strain of Pseudomonas aeruginosa. N2O conversion efficiencies > 90% were achieved when a potential of 0.8 V was applied to the MEC. The ΔnosZ strain was enriched in the 0.8 V MEC, but Achromobacter dominated the non-current control. Nitric oxide reductase genes were highly expressed by ΔnosZ cells growing in the 0.8 V MEC, consistent with enhanced nitrous oxide production rates. Concentrations of phenazine derivatives and transcripts from phenazine biosynthesis genes were also high in the 0.8 V MEC. Phenazine derivatives are known to act as electron shuttles, enhance biofilm formation, and help ward off competitors, thereby increasing the survivability of the ΔnosZ strain in the MEC. These results show that applied current stabilized growth of the ΔnosZ strain in the reactor and allowed it to sustainably generate high concentrations of nitrous oxide.
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Affiliation(s)
- Hanbing Nie
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yan Dang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Hongkang Yan
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Dezhi Sun
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
| | - Dawn E Holmes
- Department of Physical and Biological Sciences, Western New England University, 1215 Wilbraham Rd, Springfield, MA 01119, United States
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43
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Chukwubuikem A, Berger C, Mady A, Rosenbaum MA. Role of phenazine-enzyme physiology for current generation in a bioelectrochemical system. Microb Biotechnol 2021; 14:1613-1626. [PMID: 34000093 PMCID: PMC8313257 DOI: 10.1111/1751-7915.13827] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/14/2021] [Accepted: 04/27/2021] [Indexed: 02/06/2023] Open
Abstract
Pseudomonas aeruginosa produces phenazine-1-carboxylic acid (PCA) and pyocyanin (PYO), which aid its anaerobic survival by mediating electron transfer to distant oxygen. These natural secondary metabolites are being explored in biotechnology to mediate electron transfer to the anode of bioelectrochemical systems. A major challenge is that only a small fraction of electrons from microbial substrate conversion is recovered. It remained unclear whether phenazines can re-enter the cell and thus, if the electrons accessed by the phenazines arise mainly from cytoplasmic or periplasmic pathways. Here, we prove that the periplasmic glucose dehydrogenase (Gcd) of P. aeruginosa and P. putida is involved in the reduction of natural phenazines. PYO displayed a 60-fold faster enzymatic reduction than PCA; PCA was, however, more stable for long-term electron shuttling to the anode. Evaluation of a Gcd knockout and overexpression strain showed that up to 9% of the anodic current can be designated to this enzymatic reaction. We further assessed phenazine uptake with the aid of two molecular biosensors, which experimentally confirm the phenazines' ability to re-enter the cytoplasm. These findings significantly advance the understanding of the (electro) physiology of phenazines for future tailoring of phenazine electron discharge in biotechnological applications.
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Affiliation(s)
- Anthony Chukwubuikem
- Bio Pilot PlantLeibniz Institute for Natural Product Research and Infection Biology – Hans‐Knöll‐Institute (HKI)JenaGermany
- Faculty of Biological SciencesFriedrich Schiller University (FSU)JenaGermany
| | - Carola Berger
- Faculty of Biological SciencesFriedrich Schiller University (FSU)JenaGermany
| | - Ahmed Mady
- Faculty of Biological SciencesFriedrich Schiller University (FSU)JenaGermany
| | - Miriam A. Rosenbaum
- Bio Pilot PlantLeibniz Institute for Natural Product Research and Infection Biology – Hans‐Knöll‐Institute (HKI)JenaGermany
- Faculty of Biological SciencesFriedrich Schiller University (FSU)JenaGermany
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44
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Jancheva M, Böttcher T. A Metabolite of Pseudomonas Triggers Prophage-Selective Lysogenic to Lytic Conversion in Staphylococcus aureus. J Am Chem Soc 2021; 143:8344-8351. [PMID: 33978401 PMCID: PMC8193634 DOI: 10.1021/jacs.1c01275] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
Bacteriophages have
major impact on their microbial hosts and shape
entire microbial communities. The majority of these phages are latent
and reside as prophages integrated in the genomes of their microbial
hosts. A variety of intricate regulatory systems determine the switch
from a lysogenic to lytic life style, but so far strategies are lacking
to selectively control prophage induction by small molecules. Here
we show that Pseudomonas aeruginosa deploys a trigger
factor to hijack the lysogenic to lytic switch of a polylysogenic Staphylococcus aureus strain causing the selective production
of only one of its prophages. Fractionating extracts of P. aeruginosa identified the phenazine pyocyanin
as a highly potent prophage inducer of S. aureus that, in contrast to mitomycin C, displayed prophage
selectivity. Mutagenesis and biochemical investigations confirm the
existence of a noncanonical mechanism beyond SOS-response that is
controlled by the intracellular oxidation level and is prophage-selective.
Our results demonstrate that human pathogens can produce metabolites
triggering lysogenic to lytic conversion in a prophage-selective manner.
We anticipate our discovery to be the starting point of unveiling
metabolite-mediated microbe–prophage interactions and laying
the foundations for a selective small molecule controlled manipulation
of prophage activity. These could be for example applied to control
microbial communities by their built-in destruction mechanism in a
novel form of phage therapy or for the construction of small molecule-inducible
switches in synthetic biology.
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Affiliation(s)
- Magdalena Jancheva
- Department of Chemistry, Konstanz Research School Chemical Biology, Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Thomas Böttcher
- Department of Chemistry, Konstanz Research School Chemical Biology, Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany.,Faculty of Chemistry, Department of Biological Chemistry & Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria
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45
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Li XM, Ding LJ, Zhu D, Zhu YG. Long-Term Fertilization Shapes the Putative Electrotrophic Microbial Community in Paddy Soils Revealed by Microbial Electrosynthesis Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:3430-3441. [PMID: 33600162 DOI: 10.1021/acs.est.0c08022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electrotrophs play an important role in biogeochemical cycles, but the effects of long-term fertilization on electrotrophic communities in paddy soils remain unclear. Here, we explored the responses of electrotrophic communities in paddy soil-based microcosms to different long-term fertilization practices using microbial electrosynthesis systems (MESs), high-throughput quantitative PCR, and 16s rRNA gene-based Illumina sequencing techniques. Compared to the case in the unfertilized soil (CK), applications of only manure (M); only chemical nitrogen, phosphorous, and potassium fertilizers (NPK); and M plus NPK (MNPK) clearly changed the electrotrophic bacterial community structure. The Streptomyces genus of the Actinobacteria phylum was the dominant electrotroph in the CK, M, and MNPK soils. The latter two soils also favored Truepera of Deinococcus-Thermus or Arenimonas and Thioalkalispira of Proteobacteria. Furthermore, Pseudomonas of Proteobacteria and Bacillus of Firmicutes were major electrotrophs in the NPK soil. These electrotrophs consumed biocathodic currents coupled with nitrate reduction and recovered 18-38% of electrons via dissimilatory nitrate reduction to ammonium (DNRA). The increased abundances of the nrfA gene for DNRA induced by electrical potential further supported that the electrotrophs enhanced DNRA for all soils. These expand our knowledge about the diversity of electrotrophs and their roles in N cycle in paddy soils and highlight the importance of fertilization in shaping electrotrophic communities.
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Affiliation(s)
- Xiao-Min Li
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, No. 18, Haidian District, Beijing 100085, China
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Jimei Road, No. 1799, Jimei District, Xiamen 361021, China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo Urban Environment Observation and Research Station, Chinese Academy of Sciences, Zhongke Road 88, Beilun District, Ningbo 315830, China
- University of Chinese Academy of Sciences, Yuquan Road, No. 19A, Shijingshan District, Beijing 100049, China
| | - Long-Jun Ding
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, No. 18, Haidian District, Beijing 100085, China
| | - Dong Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, No. 18, Haidian District, Beijing 100085, China
| | - Yong-Guan Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, No. 18, Haidian District, Beijing 100085, China
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Jimei Road, No. 1799, Jimei District, Xiamen 361021, China
- University of Chinese Academy of Sciences, Yuquan Road, No. 19A, Shijingshan District, Beijing 100049, China
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46
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Schmitz S, Rosenbaum MA. Controlling the Production of Pseudomonas Phenazines by Modulating the Genetic Repertoire. ACS Chem Biol 2020; 15:3244-3252. [PMID: 33258592 DOI: 10.1021/acschembio.0c00805] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Microbial phenazines are getting increasing attention for antimicrobial and biotechnological applications. Phenazine production of the most well-known producer Pseudomonas aeruginosa is subject to a highly complex regulation network involving both quorum sensing and catabolite repression. These networks affect the expression of the two redundant phz gene operons responsible for phenazine-1-carboxylate (PCA) production and two specific genes phzM and phzS necessary for pyocyanin production. To decipher the specific functionality of these genes, in this study, specific phenazine gene deletion mutants of P. aeruginosa PA14 were generated and characterized in glucose and 2,3-butanediol media. Phenazine concentration and expression levels of the remaining genes were analyzed in parallel experiments. The findings suggest a strong dominance of operon phzA2-G2 resulting in a 10-fold higher expression of phz2 compared to phzA1-G1 and almost exclusive production of PCA from this operon. The genes phzM and phzS seem to exhibit antagonistic function in phenazine production. An upregulation of phzM explains the documented enhanced pyocyanin production in a 2,3-butanediol medium. Applied to a bioelectrochemical system, the altered phenazine production of the mutant strains is directly translated into current generation. Additionally, the deletion of the phenazine genes induced the activation of alternative energy pathways, which resulted in the accumulation of various fermentation products. Overall, modulating the genetic repertoire of the phenazine genes tremendously affects phenazine production levels, which are naturally kept in tight homeostasis in the P. aeruginosa wildtype. This important information can be directly utilized for ongoing efforts of heterologous biotechnological phenazine production.
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Affiliation(s)
- Simone Schmitz
- Institute of Applied Microbiology iAMB, Aachen Biology and Biotechnology ABBt, RWTH Aachen University, Aachen, Germany
| | - Miriam A. Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology − Hans-Knöll-Institute, Beutenbergstrasse 11a, Jena, Germany
- Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
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47
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Coupling an Electroactive Pseudomonas putida KT2440 with Bioelectrochemical Rhamnolipid Production. Microorganisms 2020; 8:microorganisms8121959. [PMID: 33322018 PMCID: PMC7763313 DOI: 10.3390/microorganisms8121959] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 12/16/2022] Open
Abstract
Sufficient supply of oxygen is a major bottleneck in industrial biotechnological synthesis. One example is the heterologous production of rhamnolipids using Pseudomonas putida KT2440. Typically, the synthesis is accompanied by strong foam formation in the reactor vessel hampering the process. It is caused by the extensive bubbling needed to sustain the high respirative oxygen demand in the presence of the produced surfactants. One way to reduce the oxygen requirement is to enable the cells to use the anode of a bioelectrochemical system (BES) as an alternative sink for their metabolically derived electrons. We here used a P. putida KT2440 strain that interacts with the anode using mediated extracellular electron transfer via intrinsically produced phenazines, to perform heterologous rhamnolipid production under oxygen limitation. The strain P. putida RL-PCA successfully produced 30.4 ± 4.7 mg/L mono-rhamnolipids together with 11.2 ± 0.8 mg/L of phenazine-1-carboxylic acid (PCA) in 500-mL benchtop BES reactors and 30.5 ± 0.5 mg/L rhamnolipids accompanied by 25.7 ± 8.0 mg/L PCA in electrode containing standard 1-L bioreactors. Hence, this study marks a first proof of concept to produce glycolipid surfactants in oxygen-limited BES with an industrially relevant strain.
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48
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Pan H, Pierson LS, Pierson EA. PcsR2 Is a LuxR-Type Regulator That Is Upregulated on Wheat Roots and Is Unique to Pseudomonas chlororaphis. Front Microbiol 2020; 11:560124. [PMID: 33244313 PMCID: PMC7683790 DOI: 10.3389/fmicb.2020.560124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 10/09/2020] [Indexed: 11/13/2022] Open
Abstract
LuxR solos are common in plant-associated bacteria and increasingly recognized for playing important roles in plant-microbe interkingdom signaling. Unlike the LuxR-type transcriptional regulators of prototype LuxR/LuxI quorum sensing systems, luxR solos do not have a LuxI-type autoinducer synthase gene associated with them. LuxR solos in plant-pathogenic bacteria are important for virulence and in plant endosymbionts contribute to symbiosis. In the present study, we characterized an atypical LuxR solo, PcsR2, in the biological control species Pseudomonas chlororaphis 30-84 that is highly conserved among sequenced P. chlororaphis strains. Unlike most LuxR solos in the plant-associated bacteria characterized to date, pcsR2 is not associated with a proline iminopeptidase gene and the protein has an atypical N-terminal binding domain. We created a pcsR2 deletion mutant and used quantitative RT-PCR to show that the expression of pcsR2 and genes in the operon immediately downstream was upregulated ∼10-fold when the wild type strain was grown on wheat roots compared to planktonic culture. PcsR2 was involved in upregulation. Using a GFP transcriptional reporter, we found that expression of pcsR2 responded specifically to root-derived substrates as compared to leaf-derived substrates but not to endogenous AHLs. Compared to the wild type, the mutant was impaired in the ability to utilize root carbon and nitrogen sources in wheat root macerate and to colonize wheat roots. Phenazine production and most biofilm traits previously shown to be correlated with phenazine production also were diminished in the mutant. Gene expression of several of the proteins in the phenazine regulatory network including PhzR, Pip (phenazine inducing protein) and RpeA/RpeB were reduced in the mutant, and overexpression of these genes in trans restored phenazine production in the mutant to wild-type levels, indicating PcsR2 affects the activity of the these regulatory genes upstream of RpeA/RpeB via an undetermined mechanism. Our results indicate PcsR2 upregulates the expression of the adjacent operon in response to unknown wheat root-derived signals and belongs to a novel subfamily of LuxR-type transcriptional regulators found in sequenced P. chlororaphis strains.
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Affiliation(s)
- Huiqiao Pan
- Molecular and Environmental Plant Sciences Program, Texas A&M University, College Station, TX, United States.,Department of Horticulture Sciences, Texas A&M University, College Station, TX, United States
| | - Leland S Pierson
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
| | - Elizabeth A Pierson
- Molecular and Environmental Plant Sciences Program, Texas A&M University, College Station, TX, United States.,Department of Horticulture Sciences, Texas A&M University, College Station, TX, United States.,Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
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49
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Katuri KP, Kamireddy S, Kavanagh P, Muhammad A, Conghaile PÓ, Kumar A, Saikaly PE, Leech D. Electroactive biofilms on surface functionalized anodes: The anode respiring behavior of a novel electroactive bacterium, Desulfuromonas acetexigens. WATER RESEARCH 2020; 185:116284. [PMID: 32818731 DOI: 10.1016/j.watres.2020.116284] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 08/04/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
Surface chemistry is known to influence the formation, composition, and electroactivity of electron-conducting biofilms. However, understanding of the evolution of microbial composition during biofilm development and its impact on the electrochemical response is limited. Here we present voltammetric, microscopic and microbial community analysis of biofilms formed under fixed applied potential for modified graphite electrodes during early (90 h) and mature (340 h) growth phases. Electrodes modified to introduce hydrophilic groups (-NH2, -COOH and -OH) enhance early-stage biofilm formation compared to unmodified or electrodes modified with hydrophobic groups (-C2H5). In addition, early-stage films formed on hydrophilic electrodes are dominated by the gram-negative sulfur-reducing bacterium Desulfuromonas acetexigens while Geobacter sp. dominates on -C2H5 and unmodified electrodes. As biofilms mature, current generation becomes similar, and D. acetexigens dominates in all biofilms irrespective of surface chemistry. Electrochemistry of pure culture D. acetexigens biofilms reveal that this microbe is capable of forming electroactive biofilms producing considerable current density of > 9 A/m2 in a short period of potential-induced growth (~19 h following inoculation) using acetate as an electron donor. The inability of D. acetexigens biofilms to use H2 as a sole source electron donor for current generation shows promise for maximizing H2 recovery in single-chambered microbial electrolysis cell systems treating wastewaters.
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Affiliation(s)
- Krishna P Katuri
- School of Chemistry & Ryan Institute, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland; Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Sirisha Kamireddy
- School of Chemistry & Ryan Institute, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland; Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Paul Kavanagh
- School of Chemistry & Ryan Institute, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Ali Muhammad
- Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Peter Ó Conghaile
- School of Chemistry & Ryan Institute, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Amit Kumar
- School of Chemistry & Ryan Institute, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Pascal E Saikaly
- Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Dónal Leech
- School of Chemistry & Ryan Institute, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland.
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50
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Chen H, Simoska O, Lim K, Grattieri M, Yuan M, Dong F, Lee YS, Beaver K, Weliwatte S, Gaffney EM, Minteer SD. Fundamentals, Applications, and Future Directions of Bioelectrocatalysis. Chem Rev 2020; 120:12903-12993. [DOI: 10.1021/acs.chemrev.0c00472] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Hui Chen
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Olja Simoska
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Koun Lim
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Matteo Grattieri
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Mengwei Yuan
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Fangyuan Dong
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Yoo Seok Lee
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Kevin Beaver
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Samali Weliwatte
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Erin M. Gaffney
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Shelley D. Minteer
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
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