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Tunçer Çağlayan S, Gurbanov R. Modulation of bacterial membranes and cellular macromolecules by dimethyl sulfoxide: A dose-dependent study providing novel insights. Int J Biol Macromol 2024; 267:131581. [PMID: 38615866 DOI: 10.1016/j.ijbiomac.2024.131581] [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: 11/10/2023] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 04/16/2024]
Abstract
Using Escherichia coli as a model, this manuscript delves into the intricate interactions between dimethyl sulfoxide (DMSO) and membranes, cellular macromolecules, and the effects on various aspects of bacterial physiology. Given DMSO's wide-ranging use as a solvent in microbiology, we investigate the impacts of both non-growth inhibitory (1.0 % and 2.5 % v/v) and slightly growth-inhibitory (5.0 % v/v) concentrations of DMSO. The results demonstrate that DMSO causes alterations in bacterial membrane potential, influences the electrochemical characteristics of the cell surface, and exerts substantial effects on the composition and structure of cellular biomolecules. Genome-wide gene expression data from DMSO-treated E. coli was used to further investigate and bolster the results. The findings of this study provide valuable insights into the complex relationship between DMSO and biological systems, with potential implications in drug delivery and cellular manipulation. However, it is essential to exercise caution when utilizing DMSO to enhance the solubility and delivery of bioactive compounds, as even at low concentrations, DMSO exerts non-inert effects on cellular macromolecules and processes.
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Affiliation(s)
- Sinem Tunçer Çağlayan
- Vocational School of Health Services, Department of Medical Services and Techniques, Bilecik Şeyh Edebali University, 11100 Bilecik, Turkey.
| | - Rafig Gurbanov
- Department of Bioengineering, Bilecik Şeyh Edebali University, 11100 Bilecik, Turkey; Central Research Laboratory, Bilecik Şeyh Edebali University, 11100 Bilecik, Turkey
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Li Y, Chen M, Liu H, Zhang D, Shi QS, Xie XB, Guo Y. Antimicrobial Peptide-Inspired Design of Amino-Modified Lignin with Improved Antimicrobial Activities. Biomacromolecules 2023; 24:5381-5393. [PMID: 37908117 DOI: 10.1021/acs.biomac.3c00841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
A major challenge to make use of lignin as an antimicrobial material is the weak antimicrobial activity of industrial lignin. Inspired by the antimicrobial mechanism of actions of antimicrobial peptides, alkyldiamines were employed as lysine mimics for lignin modifications. Accordingly, aminoalkyl-modified lignins with different degrees of substitution of amino groups and different hydrophobicity were synthesized. The chemical structure, properties, and antimicrobial activities of the as-prepared aminoalkyl lignins were thoroughly characterized with state-of-the-art technologies. The results indicated that aminobutyl lignin showed enhanced antimicrobial activity against S. aureus and E. coli and performed even better than copper ions. The antimicrobial mechanism of action of the as-prepared aminobutyl lignin was similar to that of polylysine, which damaged the cell membrane, leading to the leakage of intracellular molecules and death of the cell. This study provides a feasible approach to afford modified lignin with enhanced antimicrobial performance, which would facilitate the high-value valorization of lignin as biological materials.
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Affiliation(s)
- Yan Li
- Liaoning Key Lab of Lignocellulose Chemistry and BioMaterials, Liaoning Collaborative Innovation Center for Lignocellulosic Biorefinery, College of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian 116034, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, People's Republic of China
| | - Mingjie Chen
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, People's Republic of China
| | - Huiming Liu
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, People's Republic of China
| | - Dandan Zhang
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, People's Republic of China
| | - Qing-Shan Shi
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, People's Republic of China
| | - Xiao-Bao Xie
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, People's Republic of China
| | - Yanzhu Guo
- Liaoning Key Lab of Lignocellulose Chemistry and BioMaterials, Liaoning Collaborative Innovation Center for Lignocellulosic Biorefinery, College of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian 116034, China
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Rychtowski P, Paszkiewicz O, Román-Martínez MC, Lillo-Ródenas MÁ, Markowska-Szczupak A, Tryba B. Impact of TiO 2 Reduction and Cu Doping on Bacteria Inactivation under Artificial Solar Light Irradiation. Molecules 2022; 27:molecules27249032. [PMID: 36558165 PMCID: PMC9784163 DOI: 10.3390/molecules27249032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/13/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Preparation of TiO2 using the hydrothermal treatment in NH4OH solution and subsequent thermal heating at 500-700 °C in Ar was performed in order to introduce some titania surface defects. The highest amount of oxygen vacancies and Ti3+ surface defects were observed for a sample heat-treated at 500 °C. The presence of these surface defects enhanced photocatalytic properties of titania towards the deactivation of two bacteria species, E. coli and S. epidermidis, under artificial solar lamp irradiation. Further modification of TiO2 was targeted towards the doping of Cu species. Cu doping was realized through the impregnation of the titania surface by Cu species supplied from various copper salts in an aqueous solution and the subsequent heating at 500 °C in Ar. The following precursors were used as a source of Cu: CuSO4, CuNO3 or Cu(CH3COO)2. Cu doping was performed for raw TiO2 after a hydrothermal process with and without NH4OH addition. The obtained results indicate that Cu species were deposited on the titania surface defects in the case of reduced TiO2, but on the TiO2 without NH4OH modification, Cu species were attached through the titania adsorbed hydroxyl groups. Cu doping on TiO2 increased the absorption of light in the visible range. Rapid inactivation of E. coli within 30 min was obtained for the ammonia-reduced TiO2 heated at 500 °C and TiO2 doped with Cu from CuSO4 solution. Photocatalytic deactivation of S. epidermidis was greatly enhanced through Cu doping on TiO2. Impregnation of TiO2 with CuSO4 was the most effective for inactivation of both E. coli and S. epidermidis.
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Affiliation(s)
- Piotr Rychtowski
- Department of Catalytic and Sorbent Materials Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pułaskiego 10, 70–322 Szczecin, Poland
- Correspondence:
| | - Oliwia Paszkiewicz
- Department of Chemical and Process Engineering, West Pomeranian University of Technology, Piastów 42, 71–065 Szczecin, Poland
| | - Maria Carmen Román-Martínez
- Department of Inorganic Chemistry and Materials Institute (IUMA), Faculty of Sciences, University of Alicante, Carretera de San Vicente del Raspeig s/n, 03690 Alicante, Spain
| | - Maria Ángeles Lillo-Ródenas
- Department of Inorganic Chemistry and Materials Institute (IUMA), Faculty of Sciences, University of Alicante, Carretera de San Vicente del Raspeig s/n, 03690 Alicante, Spain
| | - Agata Markowska-Szczupak
- Department of Chemical and Process Engineering, West Pomeranian University of Technology, Piastów 42, 71–065 Szczecin, Poland
| | - Beata Tryba
- Department of Catalytic and Sorbent Materials Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Pułaskiego 10, 70–322 Szczecin, Poland
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Gu D, Liu Y, Zhu H, Gan Y, Zhang B, Yang W, Hao J. Magnetic porphyrin-based metal organic gel for rapid RhB removal and enhanced antibacterial activity by heterogeneous Photo-Fenton reaction under visible light. CHEMOSPHERE 2022; 303:135114. [PMID: 35623427 DOI: 10.1016/j.chemosphere.2022.135114] [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: 04/10/2022] [Revised: 05/16/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
Nanomaterials with visible light-driven catalytic ability are beneficial in controlling environmental pollutants. Porphyrin-based metal organic gel (MOG) was herein synthesized in one step and magnetic metal organic gel (MMOG) was successfully prepared via in-situ reaction of MOG and Fe3O4. This MMOG was developed as a novel visible light assisted Fenton-like catalyst. The catalytic experiments showed the high photo-Fenton activity of MMOG in the degradation of Rhodamine B (RhB) in the presence of visible light and H2O2 with a RhB degradation efficiency of 94.2% within 40 min. Notably, the obtained MMOG can kill E. coli and S. aureus with high killing rate (>99.999%) under visible light. Importantly, the MMOG can be recovered simply by an external magnetic field due to the unique magnetic property. This easily synthesized MMOG with photo-Fenton activity under visible light and magnetic property makes MOG based on the photo-Fenton reaction a prospective material for the environmental and biomedical applications.
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Affiliation(s)
- Dongxu Gu
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 610054, PR China
| | - Yu Liu
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 610054, PR China.
| | - Hongyu Zhu
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 610054, PR China
| | - Ying Gan
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 610054, PR China
| | - Biao Zhang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 610054, PR China
| | - Weiting Yang
- School of Chemical Engineering and Technology, Hainan University, Haikou, 570228, PR China.
| | - Jianyuan Hao
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 610054, PR China.
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Zhao P, Geng T, Guo Y, Meng Y, Zhang H, Zhao W. Transport of E. coli colloids and surrogate microspheres in the filtration process: Effects of flow rate, media size, and media species. Colloids Surf B Biointerfaces 2022; 220:112883. [DOI: 10.1016/j.colsurfb.2022.112883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 09/15/2022] [Accepted: 09/24/2022] [Indexed: 10/14/2022]
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Activation of the Type III Secretion System of Enteropathogenic Escherichia coli Leads to Remodeling of Its Membrane Composition and Function. mSystems 2022; 7:e0020222. [PMID: 35477304 PMCID: PMC9238428 DOI: 10.1128/msystems.00202-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell envelope of Gram-negative bacteria is a complex structure, essential for bacterial survival and for resistance to many antibiotics. Channels that cross the bacterial envelope and the host cell membrane form secretion systems that are activated upon attachment to host, enabling bacteria to inject effector molecules into the host cell, required for bacterium-host interaction. The type III secretion system (T3SS) is critical for the virulence of several pathogenic bacteria, including enteropathogenic Escherichia coli (EPEC). EPEC T3SS activation is associated with repression of carbon storage regulator (CsrA), resulting in gene expression remodeling, which is known to affect EPEC central carbon metabolism and contributes to the adaptation to a cell-adherent lifestyle in a poorly understood manner. We reasoned that the changes in the bacterial envelope upon attachment to the host and the activation of a secretion system may involve a modification of the lipid composition of bacterial envelope. Accordingly, we performed a lipidomics analysis on mutant strains that simulate T3SS activation. We saw a shift in glycerophospholipid metabolism toward the formation of lysophospholipids, attributed to corresponding upregulation of the phospholipase gene pldA and the acyltransferase gene ygiH upon T3SS activation in EPEC. We also detected a shift from menaquinones and ubiquinones to undecaprenyl lipids, concomitant with abnormal synthesis of O antigen. The remodeling of lipid metabolism is mediated by CsrA and associated with increased bacterial cell size and zeta potential and a corresponding alteration in EPEC permeability to vancomycin, increasing the sensitivity of T3SS-activated strains and of adherent wild-type EPEC to the antibiotic. IMPORTANCE The characterization of EPEC membrane lipid metabolism upon attachment to the host is an important step toward a better understanding the shift of EPEC, a notable human pathogen, from a planktonic to adherent lifestyle. It may also apply to other pathogenic bacteria that use this secretion system. We predict that upon attachment to host cells, the lipid remodeling upon T3SS activation contributes to bacterial fitness and promotes host colonization, and we show that it is associated with increased cell permeability and higher sensitivity to vancomycin. To the best of our knowledge, this is the first demonstration of a bacterial lipid remodeling due to activation of a secretion system.
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Zuo X, Suo P, Li Y, Xu Q. Diversity and distribution of antibiotic resistance genes associated with road sediments transported in urban stormwater runoff. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 292:118470. [PMID: 34748884 DOI: 10.1016/j.envpol.2021.118470] [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] [Received: 06/02/2021] [Revised: 10/24/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Recently, increasing attention has been paid to antibiotic resistance genes (ARGs) in urban stormwater runoff. However, there were little data on the diversity and distribution of ARGs associated with road sediments transported in runoff. The investigation of ARGs diversity showed that sulfonamide resistance genes (sul2 and sul3) occupied 61.7%-82.3% of total ARGs in runoff. The analysis of ARGs distribution in particulate matter (PM) implied that both tetQ and trbC existed mainly in PM with size of 150-300 μm, but other ARGs and mobile genetic elements (MGEs) were dominant in PM with size <75 μm. The discussion of potential hosts indicated that target genes (ermF, blaOXA1/blaOXA30, ermC, qnrA, sul2, tnpA-01, intI2, tetW, intI1, sul3, trbC) had the strongest subordinate relationship with Proteobacteria at phylum level and Enterobacter at genus level. The effect evaluation of ARGs distribution suggested that 13 kinds of ARGs were positively correlated with Pr/PS and Zeta potential, resulting in the more ARGs in PM with smaller size (<75 μm).
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Affiliation(s)
- XiaoJun Zuo
- Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China; Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Joint Laboratory of Atmospheric Pollution Control, Nanjing, 210044, China.
| | - PengCheng Suo
- Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China; Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Joint Laboratory of Atmospheric Pollution Control, Nanjing, 210044, China
| | - Yang Li
- Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China; Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Joint Laboratory of Atmospheric Pollution Control, Nanjing, 210044, China
| | - Qiangqiang Xu
- Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China; Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Joint Laboratory of Atmospheric Pollution Control, Nanjing, 210044, China
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8
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Laible AR, Dinius A, Schrader M, Krull R, Kwade A, Briesen H, Schmideder S. Effects and interactions of metal oxides in microparticle-enhanced cultivation of filamentous microorganisms. Eng Life Sci 2021; 22:725-743. [PMID: 36514528 PMCID: PMC9731605 DOI: 10.1002/elsc.202100075] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/13/2021] [Accepted: 09/17/2021] [Indexed: 12/16/2022] Open
Abstract
Filamentous microorganisms are used as molecular factories in industrial biotechnology. In 2007, a new approach to improve productivity in submerged cultivation was introduced: microparticle-enhanced cultivation (MPEC). Since then, numerous studies have investigated the influence of microparticles on the cultivation. Most studies considered MPEC a morphology engineering approach, in which altered morphology results in increased productivity. But sometimes similar morphological changes lead to decreased productivity, suggesting that this hypothesis is not a sufficient explanation for the effects of microparticles. Effects of surface chemistry on particles were paid little attention, as particles were often considered chemically-inert and bioinert. However, metal oxide particles strongly interact with their environment. This review links morphological, physical, and chemical properties of microparticles with effects on culture broth, filamentous morphology, and molecular biology. More precisely, surface chemistry effects of metal oxide particles lead to ion leaching, adsorption of enzymes, and generation of reactive oxygen species. Therefore, microparticles interfere with gene regulation, metabolism, and activity of enzymes. To enhance the understanding of microparticle-based morphology engineering, further interactions between particles and cells are elaborated. The presented description of phenomena occurring in MPEC eases the targeted choice of microparticles, and thus, contributes to improving the productivity of microbial cultivation technology.
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Affiliation(s)
- Andreas Reiner Laible
- School of Life SciencesChair of Process Systems EngineeringTechnische Universität MünchenFreisingGermany
| | - Anna Dinius
- Institute of Biochemical EngineeringTechnische Universität BraunschweigBraunschweigGermany,Center of Pharmaceutical EngineeringTechnische Universität BraunschweigBraunschweigGermany
| | - Marcel Schrader
- Center of Pharmaceutical EngineeringTechnische Universität BraunschweigBraunschweigGermany,Institute for Particle TechnologyTechnische Universität BraunschweigBraunschweigGermany
| | - Rainer Krull
- Institute of Biochemical EngineeringTechnische Universität BraunschweigBraunschweigGermany,Center of Pharmaceutical EngineeringTechnische Universität BraunschweigBraunschweigGermany
| | - Arno Kwade
- Center of Pharmaceutical EngineeringTechnische Universität BraunschweigBraunschweigGermany,Institute for Particle TechnologyTechnische Universität BraunschweigBraunschweigGermany
| | - Heiko Briesen
- School of Life SciencesChair of Process Systems EngineeringTechnische Universität MünchenFreisingGermany
| | - Stefan Schmideder
- School of Life SciencesChair of Process Systems EngineeringTechnische Universität MünchenFreisingGermany
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9
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The attachment-detachment mechanism of ionic/nanoscale/microscale substances on quartz sand in water. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2021.09.051] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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10
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Shemesh A, Zvulunov Y, Radian A. Impact of cocultivation on the aggregation and sedimentation trends of cyanobacteria with native and modified clay minerals. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Ceresnakova M, Dully M, Murray D, Soulimane T, Hudson SP. Stent conditioned media for in vitro evaluation of hydrophobic stent coatings. Toxicol In Vitro 2021; 76:105212. [PMID: 34265393 DOI: 10.1016/j.tiv.2021.105212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 06/22/2021] [Accepted: 07/05/2021] [Indexed: 11/27/2022]
Abstract
In vitro cell studies of hydrophobic drugs face difficulties associated with their low aqueous solubility. To study poorly soluble drugs in bio-relevant media, solubilizing agents are frequently used to make stock solutions before final reconstitution in media. This results in drug concentrations that are not representative of in vivo conditions and may pose adverse effects on cells' biological functions. This is especially true of typical hydrophobic stent coatings intended for vascular applications, where poor in vitro to in vivo correlation exists. To this end, a method for preparation of hydrophobic drug suspensions in bio-relevant media via stent conditioned media using paclitaxel (PTX) as a model drug is proposed. Since the drug is present as a suspension, this media was validated for its content uniformity and potency to induce formation of micronuclei, typical of cells undergoing prolonged mitotic arrest. Further, PTX uptake by endothelial cells was quantified and showed that the PTX stent conditioned media (at a theoretical concentration of 100 μM) suppressed cellular growth equivalent to the 0.1 μM DMSO dissolved PTX.
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Affiliation(s)
- Miriama Ceresnakova
- Department of Chemical Sciences, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Michele Dully
- Department of Chemical Sciences, Bernal Institute, University of Limerick, Limerick, Ireland
| | - David Murray
- COOK Medical Ireland Limited, O'Halloran Rd, Castletroy, Limerick, Ireland
| | - Tewfik Soulimane
- Department of Chemical Sciences, Bernal Institute, University of Limerick, Limerick, Ireland.
| | - Sarah P Hudson
- Department of Chemical Sciences, Bernal Institute, University of Limerick, Limerick, Ireland.
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Zhong H, Liu X, Tian Y, Zhang Y, Liu C. Biological power generation and earthworm assisted sludge treatment wetland to remove organic matter in sludge and synchronous power generation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 776:145909. [PMID: 33639468 DOI: 10.1016/j.scitotenv.2021.145909] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
In order to eliminate the weak degradation ability of organic matter in sludge treatment wetland (STW). In current work, a combined biological power generation and earthworm assisted sludge treatment wetland (BE-STW) system is proposed for the first time to accelerate degradation and dehydration process of organics in STW, thusly, recovering biomass energy in sludge. Experimental results show that S4 system (earthworm and bioelectricity combined) yields a voltage of 0.832 V and maximum power density of 94.98 W/m2 in the 5th day. The combination of earthworm, microorganism and plants in STW system can reduce the ratio of volatile solids to total solids (VS/TS) to 15% while the removal rate of total chemical oxygen demand (TCOD) reaches 92.1%. The BE-STW system increases sludge particle size while reduces absolute value of Zeta and extracellular polymeric substances (EPS) content, so that the moisture content of effluent sludge retains to 66.8%. Meanwhile, the richness of bacterial communities in S4 proves that bioelectrochemistry and earthworm can effectively improve the sludge treatment effect.
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Affiliation(s)
- Huiyuan Zhong
- Laboratory of Water Supply and Drainage Science and Engineering, North China University of Science and Technology, Tangshan, PR China.
| | - Xiao Liu
- Laboratory of Water Supply and Drainage Science and Engineering, North China University of Science and Technology, Tangshan, PR China
| | - Yang Tian
- Laboratory of Water Supply and Drainage Science and Engineering, North China University of Science and Technology, Tangshan, PR China
| | - Ying Zhang
- Laboratory of Water Supply and Drainage Science and Engineering, North China University of Science and Technology, Tangshan, PR China
| | - Chang Liu
- South China Institute of Environmental Sciences, MEE, PR China
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13
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Yang F, Zhou L, Dong X, Zhang W, Gao S, Wang X, Li L, Yu C, Wang Q, Yuan A, Chen J. Visible-Light-Responsive Nanofibrous α-Fe 2O 3 Integrated FeOx Cluster-Templated Siliceous Microsheets for Rapid Catalytic Phenol Removal and Enhanced Antibacterial Activity. ACS APPLIED MATERIALS & INTERFACES 2021; 13:19803-19815. [PMID: 33887908 DOI: 10.1021/acsami.1c04123] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Visible-light-driven environmental contaminants control using 2D photocatalytic nanomaterials with an unconfined reaction-diffusion path is advantageous for public health. Here, cost-effective siliceous composite microsheets (FeSiO-MS) combined with two distinct refined α-Fe2O3 nanospecies as photofunctional catalysts were constructed via a one-pot synthesis approach. Through precise control of Fe2+ precursor addition, specially configured α-Fe2O3 nanofibers combined with FeOx cluster-functionalized siliceous microsheets of ∼15 nm gradually evolved from the iron oxide-bearing molecular sieve, endowing a superior light-response characteristic of the formed nanocomposite. The catalytic experiment along with the ESR study demonstrated that the produced FeSiO-MS showed reinforced photo-Fenton reactivity, which was effective for rapid phenol degradation under visible light radiation. Moreover, the phenol removal process was found to be regulated by the specially configured types and concentrations of iron oxides. Notably, the obtained composites exhibited a considerable visible-light-induced bactericidal effect against E. coli. The constructed FeSiO-MS nanocomposites as integrated and eco-friendly photocatalysts exhibit enormous potentials for environmental and hygienic application.
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Affiliation(s)
- Fu Yang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, P. R. China
| | - Liuzhu Zhou
- Center for Global Health, The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, PR China
| | - Xuexue Dong
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, P. R. China
| | - Wanyu Zhang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, P. R. China
| | - Shuying Gao
- College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, PR China
| | - Xuyu Wang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, P. R. China
| | - Lulu Li
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, P. R. China
| | - Chao Yu
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, P. R. China
| | - Qian Wang
- College of Food Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 225127, China
| | - Aihua Yuan
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, P. R. China
| | - Jin Chen
- Center for Global Health, The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, PR China
- Jiangsu Province Engineering Research Center of Antibody Drug, Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, China
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Zeta potential beyond materials science: Applications to bacterial systems and to the development of novel antimicrobials. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183597. [PMID: 33652005 DOI: 10.1016/j.bbamem.2021.183597] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 01/17/2023]
Abstract
This review summarizes the theory of zeta potential (ZP) and the most relevant data about how it has been used for studying bacteria. We have especially focused on the discovery and characterization of novel antimicrobial compounds. The ZP technique may be considered an indirect tool to estimate the surface potential of bacteria, a physical characteristic that is key to maintaining optimal cell function. For this reason, targeting the bacterial surface is of paramount interest in the development of new antimicrobials. Surface-acting agents have been found to display a remarkable bactericidal effect and have simultaneously revealed a low tendency to trigger resistance. Changes in the bacterial surface as a result of various processes can also be followed by ZP measurements. However, due to the complexity of the bacterial surface, some considerations regarding the assessment of ZP must first be taken into account. Evidence on the application of ZP measurements to the characterization of bacteria and biofilm formation is presented next. We finally discuss the feasibility of using the ZP technique to assess antimicrobial-induced changes in the bacterial surface. Among these changes are those related to the interaction of the agent with different components of the cell envelope, membrane permeabilization, and loss of viability.
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15
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Abareghi M, Keshavarzi E. Diffuse and Stern capacitances at the concave wall of spherical cavities by density functional theory. J Electroanal Chem (Lausanne) 2021. [DOI: 10.1016/j.jelechem.2021.115060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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16
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Mesones S, Mena E, López-Muñoz MJ, Adán C, Marugán J. Synergistic and antagonistic effects in the photoelectrocatalytic disinfection of water with TiO2 supported on activated carbon as a bipolar electrode in a novel 3D photoelectrochemical reactor. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.117002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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17
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Buckerfield SJ, Quilliam RS, Waldron S, Naylor LA, Li S, Oliver DM. Rainfall-driven E. coli transfer to the stream-conduit network observed through increasing spatial scales in mixed land-use paddy farming karst terrain. WATER RESEARCH X 2019; 5:100038. [PMID: 31660535 PMCID: PMC6807365 DOI: 10.1016/j.wroa.2019.100038] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/19/2019] [Accepted: 10/03/2019] [Indexed: 06/01/2023]
Abstract
Karst aquifers have distinctive hydrology and supply 25% of the world's population with drinking water, making them a critical geological setting for understanding and managing microbial water pollution. Rainfall causes elevated concentrations and loading of faecal microorganisms, e.g. E. coli, in catchment surface and groundwater systems, increasing the risk of human exposure to faecally-contaminated water. However, effective management of microbial water quality in complex karst catchments is constrained by limited understanding of E. coli - discharge responses to rainfall. We analysed how rainfall events of varying magnitude (2.4-100 mm) control E. coli-discharge dynamics at increasing spatial scales in a mixed land-use karst catchment in southwest China. During the wet season, hourly water sampling was undertaken throughout five storm events to characterise in high detail E. coli emergence with resulting flow across multiple sites of varying catchment area, stream order, and land-use. E. coli concentration was found to increase by 1-3 orders of magnitude following rainfall events. Maximum E. coli concentration and speed of E. coli recession were influenced by rainfall (amount, intensity), timing of agricultural activities, and position in the hydrological system. For high intensity events ∼90% of the cumulative E. coli export occurred within 48 h. E. coli concentration increased with increasing discharge at all sites. E. coli concentration at low discharge was higher in the headwaters than at the catchment outlet, while the rate of increase in E. coli concentration with increasing discharge appears to follow the opposite trend, being higher at the catchment outlet than the headwaters. This was attributed to the decreasing flow path gradient and increasing degree of development of the fissure network, but further event monitoring at varying catchment scales is required to confirm this relationship. The results provide novel insight into how rainfall characteristics combine with land-use and catchment hydrology to control E. coli export in karst landscapes.
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Affiliation(s)
- Sarah J. Buckerfield
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom
| | - Richard S. Quilliam
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom
| | - Susan Waldron
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Larissa A. Naylor
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Siliang Li
- Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, China
| | - David M. Oliver
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom
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18
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Zhang X, Wei J, Zhou X, Horio A, Li S, Chen Y, Jiang S, Liang Z, Wu Z, Qiu F. Evaluation of modified basalt fiber as biological carrier media for wastewater treatment with the extended DLVO theory model. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:29789-29798. [PMID: 31407258 DOI: 10.1007/s11356-019-06133-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
In this study, environment-friendly inorganic basalt fiber (BF) was used as bio-carrier for wastewater treatment. To enhance the bio-affinity, raw BF was modified by grafting the diethylamino functional groups to make the surface more hydrophilic and electro-positive. Contact angle and zeta potential of modified basalt fiber (MBF) were characterized. The capacity of MBF bio-carriers was evaluated by microorganism immobilization tests. To explain the mechanism of capacity enhancement by modification, the profiles of total interaction energy barrier between raw BF (or MBF) and bacteria (Escherichia coli, E. coli) were discussed based on the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The results showed the contact angle of fiber decreased from 89.71° to 63.08° after modification, and zeta potential increased from - 18.53 to +10.58 mV. The microorganism immobilization tests showed that the surface modification accelerated the initial bacterial adhesion on fiber. The total interaction energy barrier between MBF and E. coli disappeared as a result of electrostatic and hydrophilic attractive forces, and enhanced the irreversible adhesion. MBF bio-carrier medium provides a promising alternative to conventional bio-carrier materials for wastewater treatment. Graphical abstract.
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Affiliation(s)
- Xiaoying Zhang
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Jiangsu, 212013, China
| | - Jing Wei
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Jiangsu, 212013, China.
| | - Xiangtong Zhou
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Jiangsu, 212013, China
| | - Akihiro Horio
- Department of Civil Engineering, National Institute of Technology, Gunma College, Gunma, 371-8530, Japan
| | - Shanwei Li
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Jiangsu, 212013, China
| | - Yuanyuan Chen
- Jiangsu ATK Environmental Engineering R&D Institute, Jiangsu, 214214, China
| | - Suying Jiang
- Jiangsu ATK Environmental Engineering R&D Institute, Jiangsu, 214214, China
| | - Zhishui Liang
- School of Civil Engineering, Southeast University, Jiangsu, 210096, China
| | - Zhiren Wu
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Jiangsu, 212013, China.
| | - Fengxian Qiu
- Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Jiangsu, 212013, China
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19
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Cohen N, Zhou H, Hay AG, Radian A. Curli production enhances clay-E. coli aggregation and sedimentation. Colloids Surf B Biointerfaces 2019; 182:110361. [PMID: 31351270 DOI: 10.1016/j.colsurfb.2019.110361] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 01/02/2023]
Abstract
Curli are amyloid fibrils that polymerize extracellularly from curlin, a protein that is secreted by many enteric bacteria and is important for biofilm formation. Presented here is a systematic study of the effects of curli on bacteria-clay interactions. The aggregation trends of curli-producing and curli-deficient bacteria with clay minerals were followed using gradient-sedimentation experiments, Lumisizer measurements, bright-field and electron microscopy. The results revealed that curli-producing bacteria auto-aggregated into high-density flocs (1.23 g/cm3), ranging in size from 10 to 50 μm, that settle spontaneously. In contrast, curli-deficient bacteria remained relatively stable in solution as individual cells (1-2 μm, 1.18 g/cm3), even at high ionic strength (350 mM). The stability of clay suspensions mixed with curli-deficient bacteria depended on clay type and ionic strength, the general trends being consistent with the classic DLVO theory. However, suspensions of curli-producing bacteria mixed with clays were highly unstable regardless of clay type and solution chemistry, suggesting extensive interactions between the clays and the bacteria-curli aggregates. SEM measurements revealed interesting differences in morphologies of the aggregates; montmorillonite particles coated the bacterial auto-aggregates whereas the kaolinite platelets were embedded within the larger curli-bacteria aggregates. These new observations regarding the densities, aggregation trends, and morphologies of bacteria-curli and bacteria-curli-clay complexes make it clear that production of surface appendages, such as curli, need to be considered when addressing the fate, activity and transport of bacteria - particularly in aquatic environments.
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Affiliation(s)
- Nirrit Cohen
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Hao Zhou
- Department of Microbiology, Cornell University, Ithaca, NY 14853 USA
| | - Anthony G Hay
- Department of Microbiology, Cornell University, Ithaca, NY 14853 USA
| | - Adi Radian
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel.
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20
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Zhao Y, Wang X, Liu C, Wang S, Wang X, Hou H, Wang J, Li H. Purification of harvested rainwater using slow sand filters with low-cost materials: Bacterial community structure and purifying effect. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 674:344-354. [PMID: 31005836 DOI: 10.1016/j.scitotenv.2019.03.474] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 03/30/2019] [Accepted: 03/30/2019] [Indexed: 06/09/2023]
Abstract
Slow sand filters (SSFs) have been shown to effectively improve water quality. The aim of the present study was to obtain low-cost materials (LCMs) as filter mediums (FMs) to efficiently purify harvested rainwater and to document the relationship between bacterial community structure and water purification. The red clay was mixed with crushed limestone and crushed brick, respectively. The mixtures or brick powder were used as the filter media for SSFs. Laboratory column tests were conducted in conjunction with the monitoring of representative water quality parameters (COD, NH4+, CFU and total coliforms) to estimate the performance of low-cost material slow sand filters (LCM-SSFs), including the time needed for biofilm maturation. The relationship between bacterial community structure and SSF performance was determined using a combination of 16S rRNA gene sequencing and an array of statistical techniques. The results demonstrated that LCM-SSFs perform well in purifying harvested rainwater, and are of superior economic benefit. LCMs had a stronger adsorptivity than quartz sand, which enhanced the purification of harvested rainwater before the biofilms matured, and shorten the time required for biofilm maturation. During the 90-day laboratory experiment, a mixture of crushed limestone and red clay exhibited the best performance. The abundance of Opitutae could be used as a potential indicator of NH4+ removal efficiency by SSFs. Schmutzdecke was characterized by abundant, diverse and evenly distributed bacterial communities that produced rich, stable and robust environmental functions, and that possessed an excellent purifying capacity. Environmental conditions associated with low ecological stress, such as neutral pH filter mediums and lucifugal experimental conditions, were conducive to the diversity and evenness of effluent bacterial communities and improved the performance of LCM-SSFs in purifying harvested rainwater.
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Affiliation(s)
- Yuewen Zhao
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, China
| | - Xiuyan Wang
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, China.
| | - Changli Liu
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, China
| | - Shuaiwei Wang
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, China
| | - Xihua Wang
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, China
| | - Hongbing Hou
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, China
| | - Jingjing Wang
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, China
| | - Hongzhao Li
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, China
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21
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Wu T, Liu Z, Zhu D, Chen Y. Effect of the particle size and surface area on Escherichia coli attachment to mineral particles in fresh water. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2019; 54:1219-1226. [PMID: 31230514 DOI: 10.1080/10934529.2019.1632625] [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: 11/27/2018] [Revised: 06/09/2019] [Accepted: 06/11/2019] [Indexed: 06/09/2023]
Abstract
The objective of this study was to assess the effects of the particle size and specific surface area (SSA) on the attachment of Escherichia coli to sediment particles. To exclude the effect of different sediment mineral compositions, pure minerals were used, and three typical suspended sediment (<62 μm) components, quartz, K-feldspar and calcite, were separated into four groups with different grain size distributions. Equilibrium attachment experiments covering common E. coli concentrations in surface water were conducted for each group. The results show that the finer fractions of each pure mineral had the greatest attachment capacity. Different mineral properties were measured, as well as an author-defined parameter (SSA_a), which was calculated by integrating the particle size distribution and only reflected the microscopic surface areas accessible to E. coli cells (∼1 μm) while excluding the effects of nanoscopic pores (5-10 nm). Pearson correlation and partial correlation analyses suggested that the partition coefficient (Kd) was positively correlated with the clay content (CC) and SSA_a (P < 0.01). Stepwise multiple regression analysis suggested that SSA_a was the dominant factor (P < 0.01) and was a better explanatory variable than CC. Moreover, in addition to SSA_a, the zeta potential and SSA also partially explained the results (P < 0.05).
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Affiliation(s)
- Tao Wu
- State Key Laboratory of Hydroscience and Engineering, Tsinghua University , Beijing , China
| | - Zhongxiang Liu
- State Key Laboratory of Hydroscience and Engineering, Tsinghua University , Beijing , China
| | - Dejun Zhu
- State Key Laboratory of Hydroscience and Engineering, Tsinghua University , Beijing , China
| | - Yongcan Chen
- State Key Laboratory of Hydroscience and Engineering, Tsinghua University , Beijing , China
- Southwest University of Science and Technology , 59 Qinglong Road , Mianyang , Sichuan , China
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22
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Wyness AJ, Paterson DM, Mendo T, Defew EC, Stutter MI, Avery LM. Factors affecting the spatial and temporal distribution of E. coli in intertidal estuarine sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 661:155-167. [PMID: 30669048 DOI: 10.1016/j.scitotenv.2019.01.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/06/2019] [Accepted: 01/06/2019] [Indexed: 06/09/2023]
Abstract
Microbiological water quality monitoring of bathing waters does not account for faecal indicator organisms in sediments. Intertidal deposits are a significant reservoir of FIOs and this indicates there is a substantial risk to bathers through direct contact with the sediment, or through the resuspension of bacteria to the water column. Recent modelling efforts include sediment as a secondary source of contamination, however, little is known about the driving factors behind spatial and temporal variation in FIO abundance. E. coli abundance, in conjunction with a wide range of measured variables, was used to construct models to explain E. coli abundance in intertidal sediments in two Scottish estuaries. E. coli concentrations up to 6 log10 CFU 100 g dry wt-1 were observed, with optimal models accounting for E. coli variation up to an adjusted R2 of 0.66. Introducing more complex models resulted in overfitting of models, detrimentally affected the transferability of models between datasets. Salinity was the most important single variable, with season, pH, colloidal carbohydrates, organic content, bulk density and maximum air temperature also featuring in optimal models. Transfer of models, using only lower cost variables, between systems explained an average deviance of 42%. This study demonstrates the potential for cost-effective sediment characteristic monitoring to contribute to FIO fate and transport modelling and consequently the risk assessment of bathing water safety.
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Affiliation(s)
- Adam J Wyness
- Sediment Ecology Research Group, Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands, St. Andrews, Fife KY16 8LB, UK.
| | - David M Paterson
- Sediment Ecology Research Group, Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands, St. Andrews, Fife KY16 8LB, UK
| | - Tania Mendo
- Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands, St. Andrews, Fife KY16 8LB, UK
| | - Emma C Defew
- Sediment Ecology Research Group, Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands, St. Andrews, Fife KY16 8LB, UK
| | - Marc I Stutter
- Environmental and Biological Sciences Group, The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
| | - Lisa M Avery
- Environmental and Biological Sciences Group, The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
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Buckerfield SJ, Waldron S, Quilliam RS, Naylor LA, Li S, Oliver DM. How can we improve understanding of faecal indicator dynamics in karst systems under changing climatic, population, and land use stressors? - Research opportunities in SW China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 646:438-447. [PMID: 30056232 DOI: 10.1016/j.scitotenv.2018.07.292] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/10/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
Human exposure to water contaminated with faeces is a leading cause of worldwide ill-health. Contaminated water can be transmitted rapidly in karst terrain as a result of the connectivity of surface and groundwater systems, high transmissivity of aquifers over large areas, and well-developed underground conduit systems. Faecal indicator organisms (FIOs) are the most widely-used indicator of faecal contamination and microbial water quality; however, the conceptualisation of FIO risk and associated sources, pathways, and survival dynamics of FIOs in karst landscapes requires a degree of modification from traditional conceptual models of FIO fate and transfer in non-karst systems. While a number of reviews have provided detailed accounts of the state-of-the-science concerning FIO dynamics in catchments, specific reference to the uniqueness of karst and its influence on FIO fate and transfer is a common omission. In response, we use a mixed methods approach of critical review combined with a quantitative survey of 372 residents of a typical karst catchment in the southwest China karst region (SWCKR) to identify emerging research needs in an area where much of the population lives in poverty and is groundwater dependent. We found that the key research needs are to understand: 1) overland and subsurface FIO export pathways in karst hydrology under varying flow conditions; 2) urban and agricultural sources and loading in mixed land-use paddy farming catchments; 3) FIO survival in paddy farming systems and environmental matrices in karst terrain; 4) sediment-FIO interactions and legacy risk in karst terrain; and 5) key needs for improved hydrological modelling and risk assessment in karst landscapes. Improved knowledge of these research themes will enable the development of evidence-based faecal contamination mitigation strategies for managing land and water resources in the SWCKR, which is highly vulnerable to climate change impacts on water supply and quality of water resources.
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Affiliation(s)
- Sarah J Buckerfield
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK; Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China.
| | - Susan Waldron
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Richard S Quilliam
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Larissa A Naylor
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Siliang Li
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - David M Oliver
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
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