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Ge ZB, Zhai ZQ, Xie WY, Dai J, Huang K, Johnson DR, Zhao FJ, Wang P. Two-tiered mutualism improves survival and competitiveness of cross-feeding soil bacteria. THE ISME JOURNAL 2023; 17:2090-2102. [PMID: 37737252 PMCID: PMC10579247 DOI: 10.1038/s41396-023-01519-5] [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: 06/21/2023] [Revised: 09/08/2023] [Accepted: 09/13/2023] [Indexed: 09/23/2023]
Abstract
Metabolic cross-feeding is a pervasive microbial interaction type that affects community stability and functioning and directs carbon and energy flows. The mechanisms that underlie these interactions and their association with metal/metalloid biogeochemistry, however, remain poorly understood. Here, we identified two soil bacteria, Bacillus sp. BP-3 and Delftia sp. DT-2, that engage in a two-tiered mutualism. Strain BP-3 has low utilization ability of pyruvic acid while strain DT-2 lacks hexokinase, lacks a phosphotransferase system, and is defective in glucose utilization. When strain BP-3 is grown in isolation with glucose, it releases pyruvic acid to the environment resulting in acidification and eventual self-killing. However, when strain BP-3 is grown together with strain DT-2, strain DT-2 utilizes the released pyruvic acid to meet its energy requirements, consequently rescuing strain BP-3 from pyruvic acid-induced growth inhibition. The two bacteria further enhance their collective competitiveness against other microbes by using arsenic as a weapon. Strain DT-2 reduces relatively non-toxic methylarsenate [MAs(V)] to highly toxic methylarsenite [MAs(III)], which kills or suppresses competitors, while strain BP-3 detoxifies MAs(III) by methylation to non-toxic dimethylarsenate [DMAs(V)]. These two arsenic transformations are enhanced when strains DT-2 and BP-3 are grown together. The two strains, along with their close relatives, widely co-occur in soils and their abundances increase with the soil arsenic concentration. Our results reveal that these bacterial types employ a two-tiered mutualism to ensure their collective metabolic activity and maintain their ecological competitive against other soil microbes. These findings shed light on the intricateness of bacterial interactions and their roles in ecosystem functioning.
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Affiliation(s)
- Zhan-Biao Ge
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
- Centre for Agriculture and Health, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhi-Qiang Zhai
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
- Centre for Agriculture and Health, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing, 210095, China
| | - Wan-Ying Xie
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jun Dai
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ke Huang
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - David R Johnson
- Department of Environmental Microbiology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), 8600, Dübendorf, Switzerland
- Institute of Ecology and Evolution, University of Bern, 3012, Bern, Switzerland
| | - Fang-Jie Zhao
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Peng Wang
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
- Centre for Agriculture and Health, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing, 210095, China.
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Ma JW, Wu YQ, Xu CL, Luo ZX, Yu RL, Hu GR, Yan Y. Inhibitory effect of polyethylene microplastics on roxarsone degradation in soils. JOURNAL OF HAZARDOUS MATERIALS 2023; 454:131483. [PMID: 37116328 DOI: 10.1016/j.jhazmat.2023.131483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 04/20/2023] [Accepted: 04/22/2023] [Indexed: 05/19/2023]
Abstract
Roxarsone (3-nitro-4-hydroxyphenylarsonic acid, Rox(V)), an extensively used organoarsenical feed additive, enters soils through the application of Rox(V)-containing manure and further degrades to highly toxic arsenicals. Microplastics, as emerging contaminants, are also frequently detected in soils. However, the effects of microplastics on soil Rox(V) degradation are unknown. A microcosm experiment was conducted to investigate soil Rox(V) degradation responses to polyethylene (PE) microplastics and the underlying mechanisms. PE microplastics inhibited soil Rox(V) degradation, with the main products being 3-amino-4-hydroxyphenylarsonic acid [3-AHPAA(V)], N-acetyl-4-hydroxy-m-arsanilic acid [N-AHPAA(V)], arsenate [As(V)], and arsenite [As(III)]. This inhibition was likely driven by the decline in soil pH by PE microplastic addition, which may directly enhance Rox(V) sorption in soils. The decreased soil pH further suppressed the nfnB gene related to nitroreduction of Rox(V) to 3-AHPAA(V) and nhoA gene associated with acetylation of 3-AHPAA(V) to N-AHPAA(V), accompanied by a decrease in the relative abundance of possible Rox(V)-degrading bacteria (e.g., Pseudomonadales), although the diversity, composition, network complexity, and assembly of soil bacterial communities were largely influenced by Rox(V) rather than PE microplastics. Our study emphasizes microplastic-induced inhibition of Rox(V) degradation in soils and the need to consider the role of microplastics in better risk assessment and remediation of Rox(V)-contaminated soils.
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Affiliation(s)
- Jie-Wen Ma
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Ya-Qing Wu
- Instrumental Analysis Center of Huaqiao University, Huaqiao University, Xiamen 361021, China
| | - Chen-Lu Xu
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Zhuan-Xi Luo
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Rui-Lian Yu
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Gong-Ren Hu
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Yu Yan
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China.
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Huang K, Liu W, Zhao FJ. Methylarsenite is a broad-spectrum antibiotic disrupting cell wall biosynthesis and cell membrane potential. Environ Microbiol 2023; 25:562-574. [PMID: 36510854 DOI: 10.1111/1462-2920.16309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022]
Abstract
Methylarsenite (MAs(III)), a product of arsenic biomethylation or bioreduction of methylarsenate (MAs(V)), has been proposed as a primitive antibiotic. However, the antibacterial property and the bactericidal mechanism of MAs(III) remain largely unclear. In this study, we found that MAs(III) is highly toxic to 14 strains of bacteria, especially against 9 strains of Gram-positive bacteria with half maximal inhibitory concentration (IC50) in the sub micromolar range for Staphyloccocus aureus, Microbacterium sp., Pseudarthrobacter siccitolerans and several Bacillus species. In a co-culture of B. subtilis 168 and MAs(III)-producer Enterobacter sp. CZ-1, the later reduced non-toxic MAs(V) to highly toxic MAs(III) to kill the former and gain a competitive advantage. MAs(III) induced autolysis of B. subtilis 168. Deletion of the autolysins LytC, LytD, LytE, and LytF suppressed MAs(III)-induced autolysis in B. subtilis 168. Transcriptomic analysis showed that MAs(III) downregulated the expression of the major genes involved in the biosynthesis of the cell wall peptidoglycan. Overexpression of an UDP-N-acetylglucosamine enolpyruvyl transferase gene murAA alleviated MAs(III)-induced autolysis in B. subtilis 168. MAs(III) disrupted the membrane potential of B. subtilis 168 and caused severe membrane damage. The results suggest that MAs(III) is a broad-spectrum antibiotic preferentially against Gram-positive bacteria by disrupting the cell wall biosynthesis pathway and cell membrane potential.
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Affiliation(s)
- Ke Huang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Wei Liu
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Fang-Jie Zhao
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
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Zhang J, Wu YF, Tang ST, Chen J, Rosen BP, Zhao FJ. A PadR family transcriptional repressor controls transcription of a trivalent metalloid resistance operon of Azospirillum halopraeferens strain Au 4. Environ Microbiol 2022; 24:5139-5150. [PMID: 35880613 DOI: 10.1111/1462-2920.16147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/28/2022]
Abstract
Methylarsenite [MAs(III)] is a highly toxic arsenical produced by some microbes as an antibiotic. In this study, we demonstrate that a PadR family transcriptional regulator, PadRars , from Azospirillum halopraeferens strain Au 4 directly binds to the promoter region of the arsenic resistance (ars) operon (consisting of padRars , arsV, and arsW) and represses transcription of arsV and arsW genes involved in MAs(III) resistance. Quantitative reverse transcriptase PCR and transcriptional reporter assays showed that transcription of the ars operon is induced strongly by MAs(III) and less strongly by arsenite and antimonite. Electrophoretic mobility shift assays with recombinant PadRars showed that it represses transcription of the ars operon by binding to two inverted-repeat sequences within the ars promoter. PadRars has two conserved cysteine pairs, Cys56/57 and Cys133/134; mutation of the first pair to serine abolished the transcriptional response of the ars operon to trivalent metalloids, suggesting that Cys56/57 form a binding site for trivalent metalloids. Either C133S or C134S derivative responses to MAs(III) but not As(III) or Sb(III), suggesting that it is a third ligand to trivalent metalloids. PadRars represents a new type of repressor proteins regulating transcription of an ars operon involved in the resistance to trivalent metalloids, especially MAs(III). This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jun Zhang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yi-Fei Wu
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Shi-Tong Tang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Fang-Jie Zhao
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
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