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Sulser S, Vucicevic A, Bellini V, Moritz R, Delavat F, Sentchilo V, Carraro N, van der Meer JR. A bistable prokaryotic differentiation system underlying development of conjugative transfer competence. PLoS Genet 2022; 18:e1010286. [PMID: 35763548 PMCID: PMC9286271 DOI: 10.1371/journal.pgen.1010286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 07/15/2022] [Accepted: 06/08/2022] [Indexed: 12/21/2022] Open
Abstract
The mechanisms and impact of horizontal gene transfer processes to distribute gene functions with potential adaptive benefit among prokaryotes have been well documented. In contrast, little is known about the life-style of mobile elements mediating horizontal gene transfer, whereas this is the ultimate determinant for their transfer fitness. Here, we investigate the life-style of an integrative and conjugative element (ICE) within the genus Pseudomonas that is a model for a widespread family transmitting genes for xenobiotic compound metabolism and antibiotic resistances. Previous work showed bimodal ICE activation, but by using single cell time-lapse microscopy coupled to combinations of chromosomally integrated single copy ICE promoter-driven fluorescence reporters, RNA sequencing and mutant analysis, we now describe the complete regulon leading to the arisal of differentiated dedicated transfer competent cells. The regulon encompasses at least three regulatory nodes and five (possibly six) further conserved gene clusters on the ICE that all become expressed under stationary phase conditions. Time-lapse microscopy indicated expression of two regulatory nodes (i.e., bisR and alpA-bisDC) to precede that of the other clusters. Notably, expression of all clusters except of bisR was confined to the same cell subpopulation, and was dependent on the same key ICE regulatory factors. The ICE thus only transfers from a small fraction of cells in a population, with an estimated proportion of between 1.7–4%, which express various components of a dedicated transfer competence program imposed by the ICE, and form the centerpiece of ICE conjugation. The components mediating transfer competence are widely conserved, underscoring their selected fitness for efficient transfer of this class of mobile elements. Horizontal gene transfer processes among prokaryotes have raised wide interest, which is attested by broad public health concern of rapid spread of antibiotic resistances. However, we typically take for granted that horizontal transfer is the result of some underlying spontaneous low frequency event, but this is not necessarily the case. As we show here, mobile genetic elements from the class of integrative and conjugative elements (ICEs) impose a coordinated program on the host cell in order to transfer, leading to an exclusive differentiated set of transfer competent cells. We base our conclusions on single cell microscopy studies to compare the rare activation of ICE promoters in individual cells in bacterial populations, and on mutant and RNA-seq analysis to show their dependency on ICE factors. This is an important finding because it implies that conjugation itself is subject to natural selection, which would lead to selection of fitter elements that transfer better or become more widespread.
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Affiliation(s)
- Sandra Sulser
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Andrea Vucicevic
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Veronica Bellini
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Roxane Moritz
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - François Delavat
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Vladimir Sentchilo
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Nicolas Carraro
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Jan Roelof van der Meer
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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Huang H, Feng G, Wang M, Liu C, Wu Y, Dong L, Feng L, Zheng X, Chen Y. Nitric Oxide: A Neglected Driver for the Conjugative Transfer of Antibiotic Resistance Genes among Wastewater Microbiota. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:6466-6478. [PMID: 35512279 DOI: 10.1021/acs.est.2c01889] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The dissemination of plasmid-borne antibiotic resistance genes (ARGs) in wastewater is becoming an urgent concern. Previous studies mainly focused on the effects of coexisting contaminants on plasmid conjugation, but ignored the potential contribution of some byproducts inevitably released from wastewater treatment processes. Herein, we demonstrate for the first time that nitric oxide (NO), an intermediate of the wastewater nitrogen cycle, can significantly boost the conjugative transfer of plasmid RP4 from Escherichia coli K12 to different recipients (E. coli HB101, Salmonella typhimurium, and wastewater microbiota). Phenotypic and genotypic tests confirmed that NO-induced promotion was not attributed to the SOS response, a well-recognized driver for horizontal gene transfer. Instead, NO exposure increased the outer membrane permeability of both the donor and recipient by inhibiting the expression of key genes involved in lipopolysaccharide biosynthesis (such as waaJ), thereby lowering the membrane barrier for conjugation. On the other hand, NO exposure not only resulted in the accumulation of intracellular tryptophan but also triggered the deficiency of intracellular methionine, both of which were validated to play key roles in regulating the global regulatory genes (korA, korB, and trbA) of plasmid RP4, activating its encoding transfer apparatus (represented by trfAp and trbBp). Overall, our findings highlighted the risks of NO in spreading ARGs among wastewater microbiota and updated the regulation mechanism of plasmid conjugation.
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Affiliation(s)
- Haining Huang
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Guanqun Feng
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Meng Wang
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Chao Liu
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yang Wu
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Lei Dong
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
- Shanghai Municipal Engn Design Inst Grp Co. Ltd., 901 Zhongshan North Second Road, Shanghai 200092, P. R. China
| | - Leiyu Feng
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Xiong Zheng
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Yinguang Chen
- State key laboratory of pollution control and Resource reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
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Zhang G, Chen J, Li W. Conjugative antibiotic-resistant plasmids promote bacterial colonization of microplastics in water environments. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128443. [PMID: 35152101 DOI: 10.1016/j.jhazmat.2022.128443] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/25/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Both microplastic and bacterial antibiotic resistance have attracted attention worldwide. When microplastics coexist with antibiotic-resistant bacteria (ARB), which carry antibiotic resistance genes (ARGs), ARB colonize the surface of microplastics, and a unique biofilm is formed. The ARB and ARGs in biofilms are denser and more difficult to remove. However, studies on the factors influencing the formation of microplastic biofilms are limited. In this study, plasmid RP4, which appeared in wastewater treatment plants, was found to be able to promote irreversible bacterial colonization of microplastics, and the hypothetical reason was conjugative pili expression. Then, the potential conjugative pili synthesis promoter "nanoalumina" and inhibitor "free nitrous acid" (FNA) were selected to test this hypothesis. Simultaneously, nanoalumina promoted and FNA inhibited bacterial colonization when RP4 existed. Combined with the gene expression and ATP analysis results, this hypothesis was confirmed, and the mechanism of RP4 on bacterial colonization was related mainly to conjugative pili protein synthesis and intracellular ATP. In this study, the effects of plasmid RP4, nanoalumina, and FNA on the formation of microplastic biofilms were reported, which has a certain reference value for other researchers exploring microplastic biofilms.
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Affiliation(s)
- Guosheng Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China
| | - Jiping Chen
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China
| | - Weiying Li
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China.
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You X, Li H, Pan B, You M, Sun W. Interactions between antibiotics and heavy metals determine their combined toxicity to Synechocystis sp. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127707. [PMID: 34798547 DOI: 10.1016/j.jhazmat.2021.127707] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/20/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
Co-pollution of antibiotics and metals is prevailing in aquatic environments. However, risks of coexisted antibiotics and metals on aquatic organisms is unclear. This study investigated the combined toxicity of antibiotics and metals towards Synechocystis sp. PCC 6803, a cyanobacterium. We found that the joint toxicity of antibiotics and metals is dependent on their interplays. The complexation between chlortetracycline (CTC) and copper/cadmium (Cu(II)/Cd(II)) resulted in their antagonistic toxicity. Contrarily, an additive toxicity was found between florfenicol (FLO) and Cu(II)/Cd(II) due to lack of interactions between them. CTC facilitated the intracellular uptake of Cu(II) and Cd(II) by increasing the membrane permeability. However, FLO had no obvious effects on the internalization of metals in Synechocystis sp. Proteomic analysis revealed that the photosynthetic proteins was down-regulated by CTC and FLO, and ribosome was the primary target of FLO. These results were verified by parallel reaction monitoring (PRM). Cu(II) induced the up-regulation of iron-sulfur assembly, while Cd(II) disturbed the cyclic electron transport in Synechocystis sp. The co-exposure of CTC and metals markedly alleviated the dysregulation of proteins, while the co-exposure of FLO and metals down-regulated biological functions such as ATP synthesis, photosynthesis, and carbon fixation of Synechocystis sp., compared with their individuals. This supports their joint toxicity effects. Our findings provide better understanding of combined toxicity between multiple pollutants in aquatic environments.
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Affiliation(s)
- Xiuqi You
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China; College of Environmental Sciences and Engineering, Peking University, Ministry of Education, Beijing 100871, China; International Joint Laboratory for Regional Pollution Control, Ministry of Education, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Ministry of Education, Beijing 100871, China
| | - Haibo Li
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China; College of Environmental Sciences and Engineering, Peking University, Ministry of Education, Beijing 100871, China; International Joint Laboratory for Regional Pollution Control, Ministry of Education, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Ministry of Education, Beijing 100871, China
| | - Baozhu Pan
- State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China, Xi'an University of Technology, Xi'an 710048, Shaanxi, China
| | - Mingtao You
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China; College of Environmental Sciences and Engineering, Peking University, Ministry of Education, Beijing 100871, China; International Joint Laboratory for Regional Pollution Control, Ministry of Education, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Ministry of Education, Beijing 100871, China
| | - Weiling Sun
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China; College of Environmental Sciences and Engineering, Peking University, Ministry of Education, Beijing 100871, China; International Joint Laboratory for Regional Pollution Control, Ministry of Education, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Ministry of Education, Beijing 100871, China.
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Jiang Q, Feng M, Ye C, Yu X. Effects and relevant mechanisms of non-antibiotic factors on the horizontal transfer of antibiotic resistance genes in water environments: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150568. [PMID: 34627113 DOI: 10.1016/j.scitotenv.2021.150568] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/27/2021] [Accepted: 09/20/2021] [Indexed: 05/17/2023]
Abstract
Antibiotic resistance has created obstacles in the treatment of infectious diseases with antibiotics. The horizontal transfer of antibiotic resistance genes (ARGs) can exacerbate the dissemination of antibiotic resistance in water environments. In addition to antibiotic selective pressure, multiple non-antibiotic factors can affect the horizontal transfer of ARGs. Herein, we seek to comprehensively review the effects and relevant mechanisms of non-antibiotic factors on the horizontal transfer of ARGs in water environments, especially contaminants from human activities and water treatment processes. Four pathways have been identified to accomplish horizontal gene transfer (HGT), i.e., conjugation, transformation, transduction, and vesiduction. Changes in conjugative frequencies by non-antibiotic factors are mainly related to their concentrations, which conform to hormesis. Relevant mechanisms involve the alteration in cell membrane permeability, reactive oxygen species, SOS response, pilus, and mRNA expression of relevant genes. Transformation induced by extracellular DNA may be more vulnerable to non-antibiotic factors than other pathways. Except bacteriophage infection, the effects of non-antibiotic factors on transduction exhibit many similarities with that of conjugation. Given the secretion of membrane vesicles stimulated by non-antibiotic factors, their effects on vesiduction can be inferred. Furthermore, contaminants from human activities at sub-inhibitory or environmentally relevant concentrations usually promote HGT, resulting in further dissemination of antibiotic resistance. The horizontal transfer of ARGs is difficult to be inhibited by individual water treatment processes (e.g., chlorination, UV treatment, and photocatalysis) unless they attain sufficient intensity. Accordingly, the synergistic application containing two or more water treatment processes is recommended. Overall, we believe this review can elucidate the significance for risk assessments of contaminants from human activities and provide insights into the development of environment-friendly and cost-efficient water treatment processes to inhibit the horizontal transfer of ARGs.
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Affiliation(s)
- Qi Jiang
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Mingbao Feng
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Chengsong Ye
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Xin Yu
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
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Wang H, Yu P, Schwarz C, Zhang B, Huo L, Shi B, Alvarez PJJ. Phthalate Esters Released from Plastics Promote Biofilm Formation and Chlorine Resistance. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1081-1090. [PMID: 34991317 DOI: 10.1021/acs.est.1c04857] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Phthalate esters (PAEs) are commonly released from plastic pipes in some water distribution systems. Here, we show that exposure to a low concentration (1-10 μg/L) of three PAEs (dimethyl phthalate (DMP), di-n-hexyl phthalate (DnHP), and di-(2-ethylhexyl) phthalate (DEHP)) promotes Pseudomonas biofilm formation and resistance to free chlorine. At PAE concentrations ranging from 1 to 5 μg/L, genes coding for quorum sensing, extracellular polymeric substances excretion, and oxidative stress resistance were upregulated by 2.7- to 16.8-fold, 2.1- to 18.9-fold, and 1.6- to 9.9-fold, respectively. Accordingly, more biofilm matrix was produced and the polysaccharide and eDNA contents increased by 30.3-82.3 and 10.3-39.3%, respectively, relative to the unexposed controls. Confocal laser scanning microscopy showed that PAE exposure stimulated biofilm densification (volumetric fraction increased from 27.1 to 38.0-50.6%), which would hinder disinfectant diffusion. Biofilm densification was verified by atomic force microscopy, which measured an increase of elastic modulus by 2.0- to 3.2-fold. PAE exposure also stimulated the antioxidative system, with cell-normalized superoxide dismutase, catalase, and glutathione activities increasing by 1.8- to 3.0-fold, 1.0- to 2.0-fold, and 1.2- to 1.6-fold, respectively. This likely protected cells against oxidative damage by chlorine. Overall, we demonstrate that biofilm exposure to environmentally relevant levels of PAEs can upregulate molecular processes and physiologic changes that promote biofilm densification and antioxidative system expression, which enhance biofilm resistance to disinfectants.
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Affiliation(s)
- Haibo Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Pingfeng Yu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Department of Civil and Environmental Engineering, Rice University, Houston 77005, United States
| | - Cory Schwarz
- Department of Civil and Environmental Engineering, Rice University, Houston 77005, United States
| | - Bo Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Lixin Huo
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Baoyou Shi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Pedro J J Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston 77005, United States
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Gwenzi W, Selvasembian R, Offiong NAO, Mahmoud AED, Sanganyado E, Mal J. COVID-19 drugs in aquatic systems: a review. ENVIRONMENTAL CHEMISTRY LETTERS 2022; 20:1275-1294. [PMID: 35069060 PMCID: PMC8760103 DOI: 10.1007/s10311-021-01356-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 11/02/2021] [Indexed: 05/14/2023]
Abstract
The outbreak of the human coronavirus disease 2019 (COVID-19) has induced an unprecedented increase in the use of several old and repurposed therapeutic drugs such as veterinary medicines, e.g. ivermectin, nonsteroidal anti-inflammatory drugs, protein and peptide therapeutics, disease-modifying anti-rheumatic drugs and antimalarial drugs, antiretrovirals, analgesics, and supporting agents, e.g. azithromycin and corticosteroids. Excretion of drugs and their metabolites in stools and urine release these drugs into wastewater, and ultimately into surface waters and groundwater systems. Here, we review the sources, behaviour, environmental fate, risks, and remediation of those drugs. We discuss drug transformation in aquatic environments and in wastewater treatment systems. Degradation mechanisms and metabolite toxicity are poorly known. Potential risks include endocrine disruption, acute and chronic toxicity, disruption of ecosystem functions and trophic interactions in aquatic organisms, and the emergence of antimicrobial resistance.
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Affiliation(s)
- Willis Gwenzi
- Biosystems and Environmental Engineering Research Group, Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, Environment and Food Systems, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Rangabhashiyam Selvasembian
- Department of Biotechnology, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamilnadu 613401 India
| | - Nnanake-Abasi O. Offiong
- International Centre for Energy and Environmental Sustainability Research (ICEESR), University of Uyo, Uyo, Nigeria
- Department of Chemical Sciences, Faculty of Computing and Applied Sciences, Topfaith University, Mkpatak, Nigeria
| | - Alaa El Din Mahmoud
- Environmental Sciences Department, Faculty of Science, Alexandria University, Alexandria, 21511 Egypt
- Green Technology Group, Faculty of Science, Alexandria University, Alexandria, 21511 Egypt
| | - Edmond Sanganyado
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, 515063 China
| | - Joyabrata Mal
- Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, Uttar Pradesh India
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