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Tang S, Gong J, Song B, Cao W, Li J. Remediation of biochar-supported effective microorganisms and microplastics on multiple forms of heavy metals in eutrophic lake. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133098. [PMID: 38064949 DOI: 10.1016/j.jhazmat.2023.133098] [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: 09/01/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 02/08/2024]
Abstract
In mineral-rich areas, eutrophic lakes are at risk of HMs pollution. However, few papers focused on the repair of HMs in eutrophic environment. Our study analyzed multiple forms of HMs, pore structure and microbial responses in the water-sediment system of eutrophic lake treated with biochar, Effective Microorganisms (EMs) or/and microplastics (MPs). As biochar provided an ideal carrier for EMs, the remediation of biochar-supported EMs (BE) achieved the greatest repairment that improved the bacterial indexes and greatly decreased the most HMs in various forms across the water-sediment system, and it also reduced metal mobility, bioavailability and ecological risk. The addition of aged MPs (MP) stimulated the microbial activity and significantly reduced the HMs levels in different forms due to the adsorption of biofilms/EPS adhered on MPs, but it increased metals mobility and ecological risks. The strong adsorption and high mobility of aged MPs would increase enrichment of HMs and cause serious ecological hazards. The incorporation of BE and MP (MBE) also greatly reduced the HMs in full forms, which was primarily ascribed to the adsorption of superfluous biofilms/EPS, but it distinctly depressed the microbial activity. The single addition of biochar and EMs resulted in the inability of HMs to be adsorbed due to the preferentially adsorption of dissolved nutrients and the absence of effective carrier, respectively. In the remediation cases, the remarkable removal of HMs was principally accomplished by the adsorption of HMs with molecular weight below 100 kDa, especially 3 kDa ∼100 kDa, which had higher specific surfaces and abundant active matters, resulting in higher adsorption onto biofilms/EPS.
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Affiliation(s)
- Siqun Tang
- College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China; Greater Bay Area Institute for Innovation, Hunan University, Guangzhou 511300, Guangdong, PR China; Shenzhen Institute, Hunan University, Shenzhen 518000, PR China
| | - Jilai Gong
- College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China; Greater Bay Area Institute for Innovation, Hunan University, Guangzhou 511300, Guangdong, PR China; Shenzhen Institute, Hunan University, Shenzhen 518000, PR China.
| | - Biao Song
- College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China; Greater Bay Area Institute for Innovation, Hunan University, Guangzhou 511300, Guangdong, PR China; Shenzhen Institute, Hunan University, Shenzhen 518000, PR China
| | - Weicheng Cao
- College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China; Greater Bay Area Institute for Innovation, Hunan University, Guangzhou 511300, Guangdong, PR China; Shenzhen Institute, Hunan University, Shenzhen 518000, PR China
| | - Juan Li
- College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China; Greater Bay Area Institute for Innovation, Hunan University, Guangzhou 511300, Guangdong, PR China; Shenzhen Institute, Hunan University, Shenzhen 518000, PR China
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Kovács ÁT. Colony morphotype diversification as a signature of bacterial evolution. MICROLIFE 2023; 4:uqad041. [PMID: 37901115 PMCID: PMC10608940 DOI: 10.1093/femsml/uqad041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 10/05/2023] [Accepted: 10/07/2023] [Indexed: 10/31/2023]
Abstract
The appearance of colony morphotypes is a signature of genetic diversification in evolving bacterial populations. Colony structure highly depends on the cell-cell interactions and polymer production that are adjusted during evolution in an environment that allows the development of spatial structures. Nucci and colleagues describe the emergence of a rough and dry morphotype of a noncapsulated Klebsiella variicola strain during a laboratory evolution study, resembling genetic changes observed in clinical isolates.
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Affiliation(s)
- Ákos T Kovács
- Institute of Biology, Leiden University, 2333 BE Leiden, The Netherlands
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Nucci A, Janaszkiewicz J, Rocha EPC, Rendueles O. Emergence of novel non-aggregative variants under negative frequency-dependent selection in Klebsiella variicola. MICROLIFE 2023; 4:uqad038. [PMID: 37781688 PMCID: PMC10540941 DOI: 10.1093/femsml/uqad038] [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] [Received: 07/11/2023] [Revised: 09/05/2023] [Accepted: 09/09/2023] [Indexed: 10/03/2023]
Abstract
Klebsiella variicola is an emergent human pathogen causing diverse infections, some of which in the urinary tract. However, little is known about the evolution and maintenance of genetic diversity in this species, the molecular mechanisms and their population dynamics. Here, we characterized the emergence of a novel rdar-like (rough and dry) morphotype which is contingent both on the genetic background and the environment. We show that mutations in either the nitrogen assimilation control gene (nac) or the type III fimbriae regulator, mrkH, suffice to generate rdar-like colonies. These morphotypes are primarily selected for the reduced inter-cellular aggregation as a result of MrkH loss-of-function which reduces type 3 fimbriae expression. Additionally, these clones also display increased growth rate and reduced biofilm formation. Direct competitions between rdar and wild type clones show that mutations in mrkH provide large fitness advantages. In artificial urine, the morphotype is under strong negative frequency-dependent selection and can socially exploit wild type strains. An exhaustive search for mrkH mutants in public databases revealed that ca 8% of natural isolates analysed had a truncated mrkH gene many of which were due to insertions of IS elements, including a reported clinical isolate with rdar morphology. These strains were rarely hypermucoid and often isolated from human, mostly from urine and blood. The decreased aggregation of these mutants could have important clinical implications as we hypothesize that such clones could better disperse within the host allowing colonisation of other body sites and potentially leading to systemic infections.
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Affiliation(s)
- Amandine Nucci
- Institut Pasteur, Université Paris Cité, CNRS, UMR3525, Microbial Evolutionary Genomics, F-75015, Paris, France
| | - Juliette Janaszkiewicz
- Institut Pasteur, Université Paris Cité, CNRS, UMR3525, Microbial Evolutionary Genomics, F-75015, Paris, France
| | - Eduardo P C Rocha
- Institut Pasteur, Université Paris Cité, CNRS, UMR3525, Microbial Evolutionary Genomics, F-75015, Paris, France
| | - Olaya Rendueles
- Institut Pasteur, Université Paris Cité, CNRS, UMR3525, Microbial Evolutionary Genomics, F-75015, Paris, France
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