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Gómez-Bolívar J, Warburton MP, Mumford AD, Mujica-Alarcón JF, Anguilano L, Onwukwe U, Barnes J, Chronopoulou M, Ju-Nam Y, Thornton SF, Rolfe SA, Ojeda JJ. Spectroscopic and Microscopic Characterization of Microbial Biofouling on Aircraft Fuel Tanks. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 38319653 PMCID: PMC10883048 DOI: 10.1021/acs.langmuir.3c02803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Avoiding microbial contamination and biofilm formation on the surfaces of aircraft fuel tanks is a major challenge in the aviation industry. The inevitable presence of water in fuel systems and nutrients provided by the fuel makes an ideal environment for bacteria, fungi, and yeast to grow. Understanding how microbes grow on different fuel tank materials is the first step to control biofilm formation in aviation fuel systems. In this study, biofilms of Pseudomonas putida, a model Gram-negative bacterium previously found in aircraft fuel tanks, were characterized on aluminum 7075-T6 surfaces, which is an alloy used by the aviation industry due to favorable properties including high strength and fatigue resistance. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) showed that extracellular polymeric substances (EPS) produced by P. putida were important components of biofilms with a likely role in biofilm stability and adhesion to the surfaces. EDX analysis showed that the proportion of phosphorus with respect to nitrogen is higher in the EPS than in the bacterial cells. Additionally, different morphologies in biofilm formation were observed in the fuel phase compared to the water phase. Micro-Fourier transform infrared spectroscopy (micro-FTIR) analysis suggested that phosphoryl and carboxyl functional groups are fundamental for the irreversible attachment between the EPS of bacteria and the aluminum surface, by the formation of hydrogen bonds and inner-sphere complexes between the macromolecules and the aluminum surface. Based on the hypothesis that nucleic acids (particularly DNA) are an important component of EPS in P. putida biofilms, the impact of degrading extracellular DNA was tested. Treatment with the enzyme DNase I affected both water and fuel phase biofilms─with the cell structure disrupted in the aqueous phase, but cells remained attached to the aluminum coupons.
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Affiliation(s)
- Jaime Gómez-Bolívar
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
- Department of Chemical Engineering, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, U.K
| | - Martin P Warburton
- Department of Chemical Engineering, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, U.K
| | - Adam D Mumford
- Department of Chemical Engineering, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, U.K
| | | | - Lorna Anguilano
- Experimental Techniques Centre, Brunel University London, Uxbridge UB8 3PH, U.K
| | - Uchechukwu Onwukwe
- Experimental Techniques Centre, Brunel University London, Uxbridge UB8 3PH, U.K
| | - James Barnes
- Airbus Operations Ltd, Pegasus House, Aerospace Avenue, Filton, Bristol BS34 7PA, U.K
| | | | - Yon Ju-Nam
- Department of Chemical Engineering, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, U.K
| | - Steven F Thornton
- Groundwater Protection and Restoration Group, Department of Civil & Structural Engineering, Broad Lane, University of Sheffield, Sheffield S3 7HQ, U.K
| | - Stephen A Rolfe
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - Jesús J Ojeda
- Department of Chemical Engineering, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, U.K
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2
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Kalia VC, Patel SKS, Lee JK. Bacterial biofilm inhibitors: An overview. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 264:115389. [PMID: 37634478 DOI: 10.1016/j.ecoenv.2023.115389] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/05/2023] [Accepted: 08/17/2023] [Indexed: 08/29/2023]
Abstract
Bacteria that cause infectious diseases adopt biofilms as one of their most prevalent lifestyles. Biofilms enable bacteria to tolerate environmental stress and evade antibacterial agents. This bacterial defense mechanism has rendered the use of antibiotics ineffective for the treatment of infectious diseases. However, many highly drug-resistant microbes have rapidly emerged owing to such treatments. Different signaling mechanisms regulate bacterial biofilm formation, including cyclic dinucleotide (c-di-GMP), small non-coding RNAs, and quorum sensing (QS). A cell density-dependent phenomenon, QS is associated with c-di-GMP (a global messenger), which regulates gene expression related to adhesion, extracellular matrix production, the transition from the planktonic to biofilm stage, stability, pathogenicity, virulence, and acquisition of nutrients. The article aims to provide information on inhibiting biofilm formation and disintegrating mature/preformed biofilms. This treatment enables antimicrobials to target the free-living/exposed bacterial cells at lower concentrations than those needed to treat bacteria within the biofilm. Therefore, a complementary action of antibiofilm and antimicrobial agents can be a robust strategic approach to dealing with infectious diseases. Taken together, these molecules have broad implications for human health.
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Affiliation(s)
- Vipin Chandra Kalia
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Sanjay K S Patel
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Jung-Kul Lee
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
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3
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Chen J, Qu C, Lu M, Zhang M, Wu Y, Gao C, Huang Q, Cai P. Extracellular polymeric substances and mineral interfacial reactions control the simultaneous immobilization and reduction of arsenic (As(V)). JOURNAL OF HAZARDOUS MATERIALS 2023; 456:131651. [PMID: 37245361 DOI: 10.1016/j.jhazmat.2023.131651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/18/2023] [Accepted: 05/14/2023] [Indexed: 05/30/2023]
Abstract
Extracellular polymeric substances (EPS) play a crucial role in controlling the mobility and bioavailability of heavy metal(loid)s in water, soils, and sediments. The formation of EPS-mineral complex changes the reactivity of the end-member materials. However, little is known about the adsorption and redox mechanisms of arsenate (As(V)) in EPS and EPS-mineral complexes. Here we examined the reaction sites, valence state, thermodynamic parameters and distribution of As in the complexes using potentiometric titration, isothermal titration calorimetry (ITC), FTIR, XPS, and SEM-EDS. The results showed that ∼54% of As(V) was reduced to As(III) by EPS, potentially driven by an enthalpy change (ΔH) of - 24.95 kJ/mol. The EPS coating on minerals clearly affected the reactivity to As(V). The strong masking of functional sites between EPS and goethite inhibited both the adsorption and reduction of As. In contrast, the weak binding of EPS onto montmorillonite retained more reactive sites for the reaction with As. Meanwhile, montmorillonite facilitated the immobilization of As to EPS through the formation of As-organic bounds. Our findings deepen the understanding of EPS-mineral interfacial reactions in controlling the redox and mobility of As, and the knowledge is important for predicting the behavior of As in natural environments.
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Affiliation(s)
- Jinzhao Chen
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Chenchen Qu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China.
| | - Man Lu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Ming Zhang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Yichao Wu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Chunhui Gao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiaoyun Huang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Peng Cai
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China
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4
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Priyadarshanee M, Das S. Bacterial extracellular polymeric substances: Biosynthesis and interaction with environmental pollutants. CHEMOSPHERE 2023; 332:138876. [PMID: 37164199 DOI: 10.1016/j.chemosphere.2023.138876] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 04/12/2023] [Accepted: 05/06/2023] [Indexed: 05/12/2023]
Abstract
Extracellular polymeric substances (EPS) are highly hydrated matrices produced by bacteria, containing various polymers such as polysaccharides, proteins, lipids, and DNA. Extracellular polymer concentrations, ions, and functional groups provide physical stability to the EPS. Constituents of EPS form the three-dimensional architecture and help acquire nutrition for the bacteria. Structural and functional diversity of the extracellular polymer depends on the specific glycosyltransferases, polymerase and transporter proteins. These enzymes are encoded by specific genes present in operons such as crd, alg, wca, and gum reported in Agrobacterium, Pseudomonas, Enterobacteriaceae, and Xanthomonas. The operons regulate the biosynthesis of extracellular polymers such as curdlan, alginate, colonic acid, and xanthan, respectively. Various functional groups in the EPS, such as carbonyl, hydroxyl, phosphoryl, and amide, provide the sorption site for interaction with environmental pollutants. Hydrophobic interactions and coordinate bonds mainly dominate the binding of EPS with environmental pollutants. EPS binds, emulsifies, and solubilizes the organic compounds, enhancing the degradation process. EPS binds with heavy metals through complexation, surface adsorption, precipitation, and ion exchange mechanisms. The biodegradability efficiency and nontoxicity properties of EPS make it an excellent biopolymer for decontaminating environmental pollutants. This review summarizes an overview of the biosynthetic mechanisms and interaction of the bacterial extracellular polymer with environmental pollutants. Interaction mechanisms of pollutants with EPS and EPS-mediated bioremediation will help develop removal applications. Moreover, understanding the genes responsible for EPS production, and implementation of new genetic methodology can be helpful for the enhanced biosynthesis of EPS to control pollution by sequestrating more environmental pollutants.
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Affiliation(s)
- Monika Priyadarshanee
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769 008, Odisha, India
| | - Surajit Das
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769 008, Odisha, India.
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5
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He J, Gao X, Huang H, Hao J. Proposal and Verification of the Theory of Layer-by-Layer Elimination of Biofilm in Listeria monocytogenes. Foods 2023; 12:foods12071361. [PMID: 37048183 PMCID: PMC10093742 DOI: 10.3390/foods12071361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Biofilms are microbial communities that represent a high abundance of microbial life forms on Earth. Within biofilms, structural changes during clearance processes occur in three spatial and temporal dimensions; therefore, microscopy and quantitative image analysis are essential in elucidating their function. Here, we present confocal laser scanning microscopy (CLSM) in conjunction with ISA-2 software analysis for the automated and high-throughput quantification, analysis, and visualisation of biofilm interiors and overall biofilm properties in three spatial and temporal dimensions. This paper discusses the removal process of Listeria monocytogenes (LM) biofilms using slightly acidic electrolytic water, non-electrolytic hypochlorite water, and alternating the use of strongly acidic and strongly alkaline electrolytic water. The results show that the biofilm gradually thins and gutters from the initial viscous dense and thick morphology under the action of either biocide. This process is consistent with first-level kinetics. After CLSM filming to observe the biofilm structure, analysis software was used to process and quantify the biovolume, average biofilm thickness, biofilm roughness and other indicators; fluorescence enzyme markers were used to verify the remaining amount of extracellular nucleic acid. In this study, we proposed and validated the theory of layer-by-layer elimination of LM biofilm.
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Affiliation(s)
- Jialin He
- College of Food Science and Biology, Hebei University of Science and Technology, No. 26 Yuxiang Street, Shijiazhuang 050018, China
| | - Xiangyu Gao
- College of Food Science and Biology, Hebei University of Science and Technology, No. 26 Yuxiang Street, Shijiazhuang 050018, China
| | - Hanbing Huang
- College of Food Science and Biology, Hebei University of Science and Technology, No. 26 Yuxiang Street, Shijiazhuang 050018, China
| | - Jianxiong Hao
- College of Food Science and Biology, Hebei University of Science and Technology, No. 26 Yuxiang Street, Shijiazhuang 050018, China
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6
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Yang K, Wang L, Cao X, Gu Z, Zhao G, Ran M, Yan Y, Yan J, Xu L, Gao C, Yang M. The Origin, Function, Distribution, Quantification, and Research Advances of Extracellular DNA. Int J Mol Sci 2022; 23:13690. [PMID: 36430193 PMCID: PMC9698649 DOI: 10.3390/ijms232213690] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/01/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
In nature, DNA is ubiquitous, existing not only inside but also outside of the cells of organisms. Intracellular DNA (iDNA) plays an essential role in different stages of biological growth, and it is defined as the carrier of genetic information. In addition, extracellular DNA (eDNA) is not enclosed in living cells, accounting for a large proportion of total DNA in the environment. Both the lysis-dependent and lysis-independent pathways are involved in eDNA release, and the released DNA has diverse environmental functions. This review provides an insight into the origin as well as the multiple ecological functions of eDNA. Furthermore, the main research advancements of eDNA in the various ecological environments and the various model microorganisms are summarized. Furthermore, the major methods for eDNA extraction and quantification are evaluated.
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Affiliation(s)
- Kaixin Yang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lishuang Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xinghong Cao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhaorui Gu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Guowei Zhao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Mengqu Ran
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yunjun Yan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jinyong Yan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Li Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Chunhui Gao
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Min Yang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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7
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An H, Tian T, Wang Z, Jin R, Zhou J. Role of extracellular polymeric substances in the immobilization of hexavalent chromium by Shewanella putrefaciens CN32 unsaturated biofilms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 810:151184. [PMID: 34699809 DOI: 10.1016/j.scitotenv.2021.151184] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/05/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Microbial remediation provides a promising avenue for the management and restoration of heavy metal-contaminated soils. Microorganisms in soils usually exist within unsaturated biofilms, however, their response to heavy metals is still limited compared to saturated biofilms. This work investigated the Cr(VI) immobilization by Shewanella putrefaciens CN32 unsaturated biofilms, and explored the underlying mechanisms of Cr(VI) complexation. Results reveal a dose-dependent toxicity of Cr(VI) to the growth of the unsaturated biofilms. During the early growth stage, the Cr(VI) addition stimulated more extracellular polymeric substances (EPS) production. In the meantime, the EPS were demonstrated to be the primary components for Cr(VI) immobilization, which accounted for more than 60% of the total adsorbed Cr(VI). The Fourier transform infrared spectra and X-ray photoelectron spectra corroborated that the binding sites for immobilizing Cr(VI) were hydroxyl, carboxyl, phosphoryl and amino functional groups of the proteins and polysaccharides in EPS. However, for the starved unsaturated biofilms, EPS were depleted and the EPS-bound Cr(VI) were released, which caused approximately 60% of the adsorbed Cr(VI) onto cell components and further aggravated the Cr(VI) stress to cells. This work extends our understanding about the Cr(VI) immobilization by unsaturated biofilms, and provides useful information for remediation of heavy metal-contaminated soils.
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Affiliation(s)
- Hui An
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Tian Tian
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Ziting Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Ruofei Jin
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China
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Mahto KU, Kumari S, Das S. Unraveling the complex regulatory networks in biofilm formation in bacteria and relevance of biofilms in environmental remediation. Crit Rev Biochem Mol Biol 2021; 57:305-332. [PMID: 34937434 DOI: 10.1080/10409238.2021.2015747] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Biofilms are assemblages of bacteria embedded within a matrix of extracellular polymeric substances (EPS) attached to a substratum. The process of biofilm formation is a complex phenomenon regulated by the intracellular and intercellular signaling systems. Various secondary messenger molecules such as cyclic dimeric guanosine 3',5'-monophosphate (c-di-GMP), cyclic adenosine 3',5'-monophosphate (cAMP), and cyclic dimeric adenosine 3',5'-monophosphate (c-di-AMP) are involved in complex signaling networks to regulate biofilm development in several bacteria. Moreover, the cell to cell communication system known as Quorum Sensing (QS) also regulates biofilm formation via diverse mechanisms in various bacterial species. Bacteria often switch to the biofilm lifestyle in the presence of toxic pollutants to improve their survivability. Bacteria within a biofilm possess several advantages with regard to the degradation of harmful pollutants, such as increased protection within the biofilm to resist the toxic pollutants, synthesis of extracellular polymeric substances (EPS) that helps in the sequestration of pollutants, elevated catabolic gene expression within the biofilm microenvironment, higher cell density possessing a large pool of genetic resources, adhesion ability to a wide range of substrata, and metabolic heterogeneity. Therefore, a comprehensive account of the various factors regulating biofilm development would provide valuable insights to modulate biofilm formation for improved bioremediation practices. This review summarizes the complex regulatory networks that influence biofilm development in bacteria, with a major focus on the applications of bacterial biofilms for environmental restoration.
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Affiliation(s)
- Kumari Uma Mahto
- Department of Life Science, Laboratory of Environmental Microbiology and Ecology (LEnME), National Institute of Technology, Odisha, India
| | - Swetambari Kumari
- Department of Life Science, Laboratory of Environmental Microbiology and Ecology (LEnME), National Institute of Technology, Odisha, India
| | - Surajit Das
- Department of Life Science, Laboratory of Environmental Microbiology and Ecology (LEnME), National Institute of Technology, Odisha, India
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9
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Panlilio H, Rice CV. The role of extracellular DNA in the formation, architecture, stability, and treatment of bacterial biofilms. Biotechnol Bioeng 2021; 118:2129-2141. [PMID: 33748946 DOI: 10.1002/bit.27760] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/01/2020] [Accepted: 03/04/2021] [Indexed: 12/16/2022]
Abstract
Advances in biotechnology to treat and cure human disease have markedly improved human health and the development of modern societies. However, substantial challenges remain to overcome innate biological factors that thwart the activity and efficacy of pharmaceutical therapeutics. Until recently, the importance of extracellular DNA (eDNA) in biofilms was overlooked. New data reveal its extensive role in biofilm formation, adhesion, and structural integrity. Different approaches to target eDNA as anti-biofilm therapies have been proposed, but eDNA and the corresponding biofilm barriers are still difficult to disrupt. Therefore, more creative approaches to eradicate biofilms are needed. The production of eDNA often originates with the genetic material of bacterial cells through cell lysis. However, genomic DNA and eDNA are not necessarily structurally or compositionally identical. Variations are noteworthy because they dictate important interactions within the biofilm. Interactions between eDNA and biofilm components may as well be exploited as alternative anti-biofilm strategies. In this review, we discuss recent developments in eDNA research, emphasizing potential ways to disrupt biofilms. This review also highlights proteins, exopolysaccharides, and other molecules interacting with eDNA that can serve as anti-biofilm therapeutic targets. Overall, the array of diverse interactions with eDNA is important in biofilm structure, architecture, and stability.
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Affiliation(s)
- Hannah Panlilio
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Charles V Rice
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
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Influence of metals and metalloids on the composition and fluorescence quenching of the extracellular polymeric substances produced by the polymorphic fungus Aureobasidium pullulans. Appl Microbiol Biotechnol 2020; 104:7155-7164. [PMID: 32577802 PMCID: PMC7374463 DOI: 10.1007/s00253-020-10732-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/29/2020] [Accepted: 06/07/2020] [Indexed: 11/14/2022]
Abstract
Abstract Aureobasidium pullulans is a ubiquitous and widely distributed fungus in the environment, and exhibits substantial tolerance against toxic metals. However, the interactions between metals and metalloids with the copious extracellular polymeric substances (EPS) produced by A. pullulans and possible relationships to tolerance are not well understood. In this study, it was found that mercury (Hg) and selenium (Se), as selenite, not only significantly inhibited growth of A. pullulans but also affected the composition of produced EPS. Lead (Pb) showed little influence on EPS yield or composition. The interactions of EPS from A. pullulans with the tested metals and metalloids depended on the specific element and their concentration. Fluorescence intensity measurements of the EPS showed that the presence of metal(loid)s stimulated the production of extracellular tryptophan-like and aromatic protein-like substances. Examination of fluorescence quenching and calculation of binding constants revealed that the fluorescence quenching process for Hg; arsenic (As), as arsenite; and Pb to EPS were mainly governed by static quenching which resulted in the formation of a stable non-fluorescent complexes between the EPS and metal(loid)s. Se showed no significant interaction with the EPS according to fluorescence quenching. These results provide further understanding of the interactions between metals and metalloids and EPS produced by fungi and their contribution to metal(loid) tolerance. Key points • Metal(loid)s enhanced production of tryptophan- and aromatic protein-like substances. • Non-fluorescent complexes formed between the EPS and tested metal(loid)s. • EPS complexation and binding of metal(loid)s was dependent on the tested element. • Metal(loid)-induced changes in EPS composition contributed to metal(loid) tolerance.
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11
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Zeng W, Zhang S, Xia M, Wu X, Qiu G, Shen L. Insights into the production of extracellular polymeric substances of Cupriavidus pauculus 1490 under the stimulation of heavy metal ions. RSC Adv 2020; 10:20385-20394. [PMID: 35520445 PMCID: PMC9054248 DOI: 10.1039/c9ra10560c] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/04/2020] [Indexed: 11/21/2022] Open
Abstract
Three different methods (a sulfuric acid method, sodium chloride method and vibration method) were used to extract extracellular polymeric substances (EPS) from Cupriavidus pauculus 1490 (C. pauculus 1490) in the present study. The sodium chloride method was able to extract the maximum amount of EPS (86.15 ± 1.50 mg g−1-DW), and could ensure minimum cell lysis by detecting glucose-6-phosphate dehydrogenase activity and using scanning electron microscopy. This method was therefore selected as the optimal extraction method and used in subsequent experiments. On this basis, the tolerance of C. pauculus 1490 and variations in EPS secretion after the addition of different metal ions was investigated. The tolerance levels of C. pauculus 1490 to Cd(ii), Ni(ii), Cu(ii) and Co(ii) were 300 mg L−1, 400 mg L−1, 400 mg L−1 and 400 mg L−1, respectively. Low concentrations of these heavy metal ions could promote bacterial growth, while increased concentrations were found to inhibit it. The results show that metal ions, especially Cd(ii), stimulate the secretion of EPS, with an EPS yield reaching 956.12 ± 10.59 mg g−1-DW at 100 mg L−1. Real-time polymerase chain reaction (PCR) analysis showed that the key EPS synthetic genes, epsB, epsP and Wzz, were up-regulated. Fourier transform infrared spectroscopy analysis suggested that abundant functional groups in EPS play an important role in heavy metal ion complexation. These results will contribute to our understanding of the tolerance mechanism of microorganisms in the presence of different types and concentrations of metal ions. Metal ions are shown to stimulate the secretion of EPS components of Cupriavidus pauculus 1490, especially Cd(II).![]()
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Affiliation(s)
- Weimin Zeng
- School of Minerals Processing and Bioengineering
- Central South University
- Changsha 410083
- China
- Key Laboratory of Biometallurgy
| | - Shishi Zhang
- School of Minerals Processing and Bioengineering
- Central South University
- Changsha 410083
- China
| | - Mingchen Xia
- School of Minerals Processing and Bioengineering
- Central South University
- Changsha 410083
- China
| | - Xueling Wu
- School of Minerals Processing and Bioengineering
- Central South University
- Changsha 410083
- China
- Key Laboratory of Biometallurgy
| | - Guanzhou Qiu
- School of Minerals Processing and Bioengineering
- Central South University
- Changsha 410083
- China
- Key Laboratory of Biometallurgy
| | - Li Shen
- School of Minerals Processing and Bioengineering
- Central South University
- Changsha 410083
- China
- Key Laboratory of Biometallurgy
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