1
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Charlton SG, Bible AN, Secchi E, Morrell‐Falvey JL, Retterer ST, Curtis TP, Chen J, Jana S. Microstructural and Rheological Transitions in Bacterial Biofilms. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2207373. [PMID: 37522628 PMCID: PMC10520682 DOI: 10.1002/advs.202207373] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 06/20/2023] [Indexed: 08/01/2023]
Abstract
Biofilms are aggregated bacterial communities structured within an extracellular matrix (ECM). ECM controls biofilm architecture and confers mechanical resistance against shear forces. From a physical perspective, biofilms can be described as colloidal gels, where bacterial cells are analogous to colloidal particles distributed in the polymeric ECM. However, the influence of the ECM in altering the cellular packing fraction (ϕ) and the resulting viscoelastic behavior of biofilm remains unexplored. Using biofilms of Pantoea sp. (WT) and its mutant (ΔUDP), the correlation between biofilm structure and its viscoelastic response is investigated. Experiments show that the reduction of exopolysaccharide production in ΔUDP biofilms corresponds with a seven-fold increase in ϕ, resulting in a colloidal glass-like structure. Consequently, the rheological signatures become altered, with the WT behaving like a weak gel, whilst the ΔUDP displayed a glass-like rheological signature. By co-culturing the two strains, biofilm ϕ is modulated which allows us to explore the structural changes and capture a change in viscoelastic response from a weak to a strong gel, and to a colloidal glass-like state. The results reveal the role of exopolysaccharide in mediating a structural transition in biofilms and demonstrate a correlation between biofilm structure and viscoelastic response.
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Affiliation(s)
- Samuel G.V. Charlton
- Department of Civil, Environmental and Geomatic EngineeringInstitute of Environmental EngineeringETH ZurichZurich8049Switzerland
- School of EngineeringNewcastle UniversityNewcastle Upon TyneNE1 7RUUK
| | - Amber N. Bible
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37830USA
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic EngineeringInstitute of Environmental EngineeringETH ZurichZurich8049Switzerland
| | | | - Scott T. Retterer
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN37830USA
- Center for Nanophase Material SciencesOak Ridge National LaboratoryOak RidgeTN37830USA
| | - Thomas P. Curtis
- School of EngineeringNewcastle UniversityNewcastle Upon TyneNE1 7RUUK
| | - Jinju Chen
- School of EngineeringNewcastle UniversityNewcastle Upon TyneNE1 7RUUK
| | - Saikat Jana
- School of EngineeringNewcastle UniversityNewcastle Upon TyneNE1 7RUUK
- School of EngineeringUlster UniversityBelfastBT15 1APUK
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2
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Crivello G, Fracchia L, Ciardelli G, Boffito M, Mattu C. In Vitro Models of Bacterial Biofilms: Innovative Tools to Improve Understanding and Treatment of Infections. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13050904. [PMID: 36903781 PMCID: PMC10004855 DOI: 10.3390/nano13050904] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 06/02/2023]
Abstract
Bacterial infections are a growing concern to the health care systems. Bacteria in the human body are often found embedded in a dense 3D structure, the biofilm, which makes their eradication even more challenging. Indeed, bacteria in biofilm are protected from external hazards and are more prone to develop antibiotic resistance. Moreover, biofilms are highly heterogeneous, with properties dependent on the bacteria species, the anatomic localization, and the nutrient/flow conditions. Therefore, antibiotic screening and testing would strongly benefit from reliable in vitro models of bacterial biofilms. This review article summarizes the main features of biofilms, with particular focus on parameters affecting biofilm composition and mechanical properties. Moreover, a thorough overview of the in vitro biofilm models recently developed is presented, focusing on both traditional and advanced approaches. Static, dynamic, and microcosm models are described, and their main features, advantages, and disadvantages are compared and discussed.
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Affiliation(s)
- G. Crivello
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy
| | - L. Fracchia
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale “A. Avogadro”, Largo Donegani 2, 28100 Novara, Italy
| | - G. Ciardelli
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy
| | - M. Boffito
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy
| | - C. Mattu
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy
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3
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Li M, Nahum Y, Matouš K, Stoodley P, Nerenberg R. Effects of biofilm heterogeneity on the apparent mechanical properties obtained by shear rheometry. Biotechnol Bioeng 2023; 120:553-561. [PMID: 36305479 DOI: 10.1002/bit.28276] [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: 07/10/2022] [Revised: 09/30/2022] [Accepted: 10/24/2022] [Indexed: 01/13/2023]
Abstract
Rheometry is an experimental technique widely used to determine the mechanical properties of biofilms. However, it characterizes the bulk mechanical behavior of the whole biofilm. The effects of biofilm mechanical heterogeneity on rheometry measurements are not known. We used laboratory experiments and computer modeling to explore the effects of biofilm mechanical heterogeneity on the results obtained by rheometry. A synthetic biofilm with layered mechanical properties was studied, and a viscoelastic biofilm theory was employed using the Kelvin-Voigt model. Agar gels with different concentrations were used to prepare the layered, heterogeneous biofilm, which was characterized for mechanical properties in shear mode with a rheometer. Both experiments and simulations indicated that the biofilm properties from rheometry were strongly biased by the weakest portion of the biofilm. The simulation results using linearly stratified mechanical properties from a previous study also showed that the weaker portions of the biofilm dominated the mechanical properties in creep tests. We note that the model can be used as a predictive tool to explore the mechanical behavior of complex biofilm structures beyond those accessible to experiments. Since most biofilms display some degree of mechanical heterogeneity, our results suggest caution should be used in the interpretation of rheometry data. It does not necessarily provide the "average" mechanical properties of the entire biofilm if the mechanical properties are stratified.
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Affiliation(s)
- Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Yanina Nahum
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Karel Matouš
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana, USA
| | - Paul Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA.,National Biofilm Innovation Centre (NBIC) and National Centre for Advanced Tribology at Southampton (nCATS), Mechanical Engineering, University of Southampton, Southampton, United Kingdom
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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4
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Huang C, Clark GG, Zaki FR, Won J, Ning R, Boppart SA, Elbanna AE, Nguyen TH. Effects of phosphate and silicate on stiffness and viscoelasticity of mature biofilms developed with simulated drinking water. BIOFOULING 2023; 39:36-46. [PMID: 36847486 PMCID: PMC10065970 DOI: 10.1080/08927014.2023.2177538] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/19/2023] [Accepted: 02/02/2023] [Indexed: 05/21/2023]
Abstract
Biofilms, a porous matrix of cells aggregated with extracellular polymeric substances under the influence of chemical constituents in the feed water, can develop a viscoelastic response to mechanical stresses. In this study, the roles of phosphate and silicate, common additives in corrosion control and meat processing, on the stiffness, viscoelasticity, porous structure networks, and chemical properties of biofilm were investigated. Three-year biofilms on PVC coupons were grown from sand-filtered groundwater with or without one of the non-nutrient (silicate) or nutrient additives (phosphate or phosphate blends). Compared with non-nutrient additives, the phosphate and phosphate-blend additives led to a biofilm with the lowest stiffness, most viscoelastic, and more porous structure, including more connecting throats with greater equivalent radii. The phosphate-based additives also led to more organic species in the biofilm matrix than the silicate additive did. This work demonstrated that nutrient additives could promote biomass accumulation but also reduce mechanical stability.
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Affiliation(s)
- Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Gemma G. Clark
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Farzana R. Zaki
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
| | - Jungeun Won
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Bioengineering, University of Illinois Urbana Champaign, 1304 West Springfield Avenue, Urbana, Illinois 61801, USA
| | - Runsen Ning
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Stephen A. Boppart
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, 506 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Bioengineering, University of Illinois Urbana Champaign, 1304 West Springfield Avenue, Urbana, Illinois 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois Urbana Champaign, 306 North Wright Street, Urbana, Illinois 61801, USA
| | - Ahmed E. Elbanna
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Thanh H. Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, 506 South Mathews Avenue, Urbana, Illinois 61801, USA
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5
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Wong LL, Mugunthan S, Kundukad B, Ho JCS, Rice SA, Hinks J, Seviour T, Parikh AN, Kjelleberg S. Microbial biofilms are shaped by the constant dialogue between biological and physical forces in the extracellular matrix. Environ Microbiol 2023; 25:199-208. [PMID: 36502515 DOI: 10.1111/1462-2920.16306] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Affiliation(s)
- Lan Li Wong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Sudarsan Mugunthan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Binu Kundukad
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - James Chin Shing Ho
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Institute for Digital Molecular Analytics and Science, Nanyang Technological University, Singapore, Singapore
| | - Scott A Rice
- CSIRO, Agriculture and Food, Microbiomes for One Systems Health, Canberra, Australia
| | - Jamie Hinks
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,WATEC Aarhus University Centre for Water Technology, Aarhus, Denmark
| | - Atul N Parikh
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Institute for Digital Molecular Analytics and Science, Nanyang Technological University, Singapore, Singapore.,Department of Biomedical Engineering, University of California, Davis, California, USA
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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6
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Candry P, Godfrey BJ, Wang Z, Sabba F, Dieppa E, Fudge J, Balogun O, Wells G, Winkler MKH. Tailoring polyvinyl alcohol-sodium alginate (PVA-SA) hydrogel beads by controlling crosslinking pH and time. Sci Rep 2022; 12:20822. [PMID: 36460678 PMCID: PMC9718846 DOI: 10.1038/s41598-022-25111-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/24/2022] [Indexed: 12/03/2022] Open
Abstract
Hydrogel-encapsulated catalysts are an attractive tool for low-cost intensification of (bio)-processes. Polyvinyl alcohol-sodium alginate hydrogels crosslinked with boric acid and post-cured with sulfate (PVA-SA-BS) have been applied in bioproduction and water treatment processes, but the low pH required for crosslinking may negatively affect biocatalyst functionality. Here, we investigate how crosslinking pH (3, 4, and 5) and time (1, 2, and 8 h) affect the physicochemical, elastic, and process properties of PVA-SA-BS beads. Overall, bead properties were most affected by crosslinking pH. Beads produced at pH 3 and 4 were smaller and contained larger internal cavities, while optical coherence tomography suggested polymer cross-linking density was higher. Optical coherence elastography revealed PVA-SA-BS beads produced at pH 3 and 4 were stiffer than pH 5 beads. Dextran Blue release showed that pH 3-produced beads enabled higher diffusion rates and were more porous. Last, over a 28-day incubation, pH 3 and 4 beads lost more microspheres (as cell proxies) than beads produced at pH 5, while the latter released more polymer material. Overall, this study provides a path forward to tailor PVA-SA-BS hydrogel bead properties towards a broad range of applications, such as chemical, enzymatic, and microbially catalyzed (bio)-processes.
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Affiliation(s)
- Pieter Candry
- grid.34477.330000000122986657Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700 USA
| | - Bruce J. Godfrey
- grid.34477.330000000122986657Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700 USA
| | - Ziwei Wang
- grid.16753.360000 0001 2299 3507Mechanical Engineering Department, Northwestern University, Evanston, IL 60208 USA
| | | | - Evan Dieppa
- grid.16753.360000 0001 2299 3507Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL 60208 USA
| | - Julia Fudge
- grid.34477.330000000122986657Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700 USA
| | - Oluwaseyi Balogun
- grid.16753.360000 0001 2299 3507Mechanical Engineering Department, Northwestern University, Evanston, IL 60208 USA ,grid.16753.360000 0001 2299 3507Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208 USA
| | - George Wells
- grid.16753.360000 0001 2299 3507Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208 USA
| | - Mari-Karoliina Henriikka Winkler
- grid.34477.330000000122986657Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700 USA
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7
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Park H, Schwartzman AF, Tang TC, Wang L, Lu TK. Ultra-lightweight living structural material for enhanced stiffness and environmental sensing. Mater Today Bio 2022; 18:100504. [PMID: 36504543 PMCID: PMC9729073 DOI: 10.1016/j.mtbio.2022.100504] [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: 09/30/2022] [Revised: 11/20/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
Natural materials such as bone, wood, and bamboo can inspire the fabrication of stiff, lightweight structural materials. Biofilms are one of the most dominant forms of life in nature. However, little is known about their physical properties as a structural material. Here we report an Escherichia coli biofilm having a Young's modulus close to 10 GPa with ultra-low density, indicating a high-performance structural material. The mechanical and structural characterization of the biofilm and its components illuminates its adaptable bottom-up design, consisting of lightweight microscale cells covered by a dense network of amyloid nanofibrils on the surface. We engineered E. coli such that 1) carbon nanotubes assembled on the biofilm, enhancing its stiffness to over 30 GPa, or that 2) the biofilm sensitively detected heavy metal as an example of an environmental toxin. These demonstrations offer new opportunities for developing responsive living structural materials to serve many real-world applications.
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Affiliation(s)
- Heechul Park
- Synthetic Biology Group, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA,Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Alan F. Schwartzman
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Tzu-Chieh Tang
- Synthetic Biology Group, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA,Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Lei Wang
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Timothy K. Lu
- Synthetic Biology Group, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA,Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA,Corresponding author. Synthetic Biology Group, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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8
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Effect of a Stannous Fluoride Dentifrice on Biofilm Composition, Gene Expression and Biomechanical Properties. Microorganisms 2022; 10:microorganisms10091691. [PMID: 36144293 PMCID: PMC9506307 DOI: 10.3390/microorganisms10091691] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
An in situ study was conducted to examine the mode of action of a 0.454% stannous fluoride (SnF2)-containing dentifrice in controlling the composition and properties of oral biofilm. Thirteen generally healthy individuals participated in the study. Each participant wore an intra-oral appliance over a 48-h period to measure differences in the resulting biofilm’s architecture, mechanical properties, and bacterial composition after using two different toothpaste products. In addition, metatranscriptomics analysis of supragingival plaque was conducted to identify the gene pathways influenced. The thickness and volume of the microcolonies formed when brushing with the SnF2 dentifrice were dramatically reduced compared to the control 0.76% sodium monofluorophosphate (MFP)-containing toothpaste. Similarly, the biophysical and nanomechanical properties measured by atomic force microscopy (AFM) demonstrated a significant reduction in biofilm adhesive properties. Metatranscriptomic analysis identified pathways associated with biofilm formation, cell adhesion, quorum sensing, and N-glycosylation that are significantly downregulated with SnF2. This study provides a clinically relevant snapshot of how the use of a stabilized, SnF2 toothpaste formulation can change the spatial organization, nanomechanical, and gene expression properties of bacterial communities.
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9
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Ma X, Liu Z, Zeng W, Lin T, Tian X, Cheng X. Crack patterns of drying dense bacterial suspensions. SOFT MATTER 2022; 18:5239-5248. [PMID: 35771131 DOI: 10.1039/d2sm00012a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Drying of bacterial suspensions is frequently encountered in a plethora of natural and engineering processes. However, the evaporation-driven mechanical instabilities of dense consolidating bacterial suspensions have not been explored heretofore. Here, we report the formation of two different crack patterns of drying suspensions of Escherichia coli (E. coli) with distinct motile behaviors. Circular cracks are observed for wild-type E. coli with active swimming, whereas spiral-like cracks form for immotile bacteria. Using the elastic fracture mechanics and the poroelastic theory, we show that the formation of the circular cracks is determined by the tensile nature of the radial drying stress once the cracks are initiated by the local order structure of bacteria due to their collective swimming. Our study demonstrates the link between the microscopic swimming behaviors of individual bacteria and the mechanical instabilities and macroscopic pattern formation of drying bacterial films. The results shed light on the dynamics of active matter in a drying process and provide useful information for understanding various biological processes associated with drying bacterial suspensions.
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Affiliation(s)
- Xiaolei Ma
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Zhengyang Liu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Wei Zeng
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
- College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China
| | - Tianyi Lin
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Xin Tian
- Department of Physics & Astronomy, University of Wyoming, Laramie, WY 82071, USA
| | - Xiang Cheng
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
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10
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Geisel S, Secchi E, Vermant J. The role of surface adhesion on the macroscopic wrinkling of biofilms. eLife 2022; 11:76027. [PMID: 35723588 PMCID: PMC9208754 DOI: 10.7554/elife.76027] [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] [Received: 12/01/2021] [Accepted: 06/01/2022] [Indexed: 12/14/2022] Open
Abstract
Biofilms, bacterial communities of cells encased by a self-produced matrix, exhibit a variety of three-dimensional structures. Specifically, channel networks formed within the bulk of the biofilm have been identified to play an important role in the colonies' viability by promoting the transport of nutrients and chemicals. Here, we study channel formation and focus on the role of the adhesion of the biofilm matrix to the substrate in Pseudomonas aeruginosa biofilms grown under constant flow in microfluidic channels. We perform phase contrast and confocal laser scanning microscopy to examine the development of the biofilm structure as a function of the substrates' surface energy. The formation of the wrinkles and folds is triggered by a mechanical buckling instability, controlled by biofilm growth rate and the film’s adhesion to the substrate. The three-dimensional folding gives rise to hollow channels that rapidly increase the effective volume occupied by the biofilm and facilitate bacterial movement inside them. The experiments and analysis on mechanical instabilities for the relevant case of a bacterial biofilm grown during flow enable us to predict and control the biofilm morphology.
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Affiliation(s)
- Steffen Geisel
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich, Switzerland
| | - Jan Vermant
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
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11
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Savorana G, Słomka J, Stocker R, Rusconi R, Secchi E. A microfluidic platform for characterizing the structure and rheology of biofilm streamers. SOFT MATTER 2022; 18:3878-3890. [PMID: 35535650 PMCID: PMC9131465 DOI: 10.1039/d2sm00258b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Biofilm formation is the most successful survival strategy for bacterial communities. In the biofilm lifestyle, bacteria embed themselves in a self-secreted matrix of extracellular polymeric substances (EPS), which acts as a shield against mechanical and chemical insults. When ambient flow is present, this viscoelastic scaffold can take a streamlined shape, forming biofilm filaments suspended in flow, called streamers. Streamers significantly disrupt the fluid flow by causing rapid clogging and affect transport in aquatic environments. Despite their relevance, the structural and rheological characterization of biofilm streamers is still at an early stage. In this work, we present a microfluidic platform that allows the reproducible growth of biofilm streamers in controlled physico-chemical conditions and the characterization of their biochemical composition, morphology, and rheology in situ. We employed isolated micropillars as nucleation sites for the growth of single biofilm streamers under the continuous flow of a diluted bacterial suspension. By combining fluorescent staining of the EPS components and epifluorescence microscopy, we were able to characterize the biochemical composition and morphology of the streamers. Additionally, we optimized a protocol to perform hydrodynamic stress tests in situ, by inducing controlled variations of the fluid shear stress exerted on the streamers by the flow. Thus, the reproducibility of the formation process and the testing protocol make it possible to perform several consistent experimental replicates that provide statistically significant information. By allowing the systematic investigation of the role of biochemical composition on the structure and rheology of streamers, this platform will advance our understanding of biofilm formation.
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Affiliation(s)
- Giovanni Savorana
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Jonasz Słomka
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Roman Stocker
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Roberto Rusconi
- Department of Biomedical Sciences, Humanitas University, 20072, Pieve Emanuele, MI, Italy
- IRCCS Humanitas Research Hospital, 20089, Rozzano, MI, Italy
| | - Eleonora Secchi
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
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12
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Babayekhorasani F, Hosseini M, Spicer PT. Molecular and Colloidal Transport in Bacterial Cellulose Hydrogels. Biomacromolecules 2022; 23:2404-2414. [PMID: 35544686 DOI: 10.1021/acs.biomac.2c00178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bacterial cellulose biofilms are complex networks of strong interwoven nanofibers that control transport and protect bacterial colonies in the film. The design of diverse applications of these bacterial cellulose films also relies on understanding and controlling transport through the fiber mesh, and transport simulations of the films are most accurate when guided by experimental characterization of the structures and the resultant diffusion inside. Diffusion through such films is a function of their key microstructural length scales, determining how molecules, as well as particles and microorganisms, permeate them. We use microscopy to study the unique bacterial cellulose film via its pore structure and quantify the mobility dynamics of various sizes of tracer particles and macromolecules. Mobility is hindered within the films, as confinement and local movement strongly depend on the void size relative to diffusing tracers. The biofilms have a naturally periodic structure of alternating dense and porous layers of nanofiber mesh, and we tune the magnitude of the spacing via fermentation conditions. Micron-sized particles can diffuse through the porous layers but cannot penetrate the dense layers. Tracer mobility in the porous layers is isotropic, indicating a largely random pore structure there. Molecular diffusion through the whole film is only slightly reduced by the structural tortuosity. Knowledge of transport variations within bacterial cellulose networks can be used to guide the design of symbiotic cultures in these structures and enhance their use in applications like biomedical implants, wound dressings, lab-grown meat, clothing textiles, and sensors.
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Affiliation(s)
| | - Maryam Hosseini
- School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Patrick T Spicer
- School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
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13
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Abstract
Streamers, filamentous bacterial biofilms formed in flowing systems, are ubiquitous in natural and artificial environments, where they cause clogging of devices and spreading of infections. Despite their impact, little is known about the nature and properties of streamers and their response to fluid flow. Here, we uncover the specific contribution of bacterial secreted extracellular DNA and exopolysaccharide Pel, two important components in Pseudomonas aeruginosa biofilms, to the formation and the mechanical properties of the streamers. We then show how this knowledge can be used to control biofilm streamer formation, both to inhibit or to promote it. Across diverse habitats, bacteria are mainly found as biofilms, surface-attached communities embedded in a self-secreted matrix of extracellular polymeric substances (EPS), which enhance bacterial recalcitrance to antimicrobial treatment and mechanical stresses. In the presence of flow and geometric constraints such as corners or constrictions, biofilms can take the form of long, suspended filaments (streamers), which bear important consequences in industrial and clinical settings by causing clogging and fouling. The formation of streamers is thought to be driven by the viscoelastic nature of the biofilm matrix. Yet, little is known about the structural composition of streamers and how it affects their mechanical properties. Here, using a microfluidic platform that allows growing and precisely examining biofilm streamers, we show that extracellular DNA (eDNA) constitutes the backbone and is essential for the mechanical stability of Pseudomonas aeruginosa streamers. This finding is supported by the observations that DNA-degrading enzymes prevent the formation of streamers and clear already formed ones and that the antibiotic ciprofloxacin promotes their formation by increasing the release of eDNA. Furthermore, using mutants for the production of the exopolysaccharide Pel, an important component of P. aeruginosa EPS, we reveal an concurring role of Pel in tuning the mechanical properties of the streamers. Taken together, these results highlight the importance of eDNA and of its interplay with Pel in determining the mechanical properties of P. aeruginosa streamers and suggest that targeting the composition of streamers can be an effective approach to control the formation of these biofilm structures.
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14
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Farjami A, Hatami MS, Siahi-Shadbad M, Lotfipour F. Peracetic acid Activity on Biofilm Formed by Escherichia coli Isolated from an Industrial Water System. Lett Appl Microbiol 2022; 74:613-621. [PMID: 34984695 DOI: 10.1111/lam.13647] [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: 05/07/2021] [Revised: 12/26/2021] [Accepted: 12/28/2021] [Indexed: 11/30/2022]
Abstract
One of the major problems in industrial water systems is the generation of biofilm, which is resistant to antimicrobial agents and causes failure of sanitization policy. This work aimed to study the anti-biofilm activity of peracetic acid (PAA) at contact times and temperatures combinations. To this end, a 96 well microtiter-based calorimetric method was applied in in vitro biofilm production using Ecsherichia coli, isolated from the water supply system of a pharmaceutical plant. The phenotypic and phylogenetic tests confirmed the isolated bacteria belong to strains of Ecsherichia coli. The anti-biofilm activity of peracetic acid on formed biofilm was investigated at concentrations of 0.15-0.5% for a contact time of 5-15 min at 20°C to 60°C. The maximum biofilm formation by MTP method using an Ecsherichia coli isolate was achieved in 96 h incubation in TSB containing wells at 37°C. Biofilm formation rate showed to be high by the environmental isolate compared with that of standard strain. PAA at concentrations above 0.25%, the temperature of 40°C, and a minimum of 10 minutes of contact time was effective in the eradication of biofilm in an MPT-based system.
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Affiliation(s)
- Afsaneh Farjami
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Mohammadreza Siahi-Shadbad
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farzaneh Lotfipour
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
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15
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Quan K, Hou J, Zhang Z, Ren Y, Peterson BW, Flemming HC, Mayer C, Busscher HJ, van der Mei HC. Water in bacterial biofilms: pores and channels, storage and transport functions. Crit Rev Microbiol 2021; 48:283-302. [PMID: 34411498 DOI: 10.1080/1040841x.2021.1962802] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Bacterial biofilms occur in many natural and industrial environments. Besides bacteria, biofilms comprise over 70 wt% water. Water in biofilms occurs as bound- or free-water. Bound-water is adsorbed to bacterial surfaces or biofilm (matrix) structures and possesses different Infra-red and Nuclear-Magnetic-Resonance signatures than free-water. Bound-water is different from intra-cellularly confined-water or water confined within biofilm structures and bacteria are actively involved in building water-filled structures by bacterial swimmers, dispersion or lytic self-sacrifice. Water-filled structures can be transient due to blocking, resulting from bacterial growth, compression or additional matrix formation and are generally referred to as "channels and pores." Channels and pores can be distinguished based on mechanism of formation, function and dimension. Channels allow transport of nutrients, waste-products, signalling molecules and antibiotics through a biofilm provided the cargo does not adsorb to channel walls and channels have a large length/width ratio. Pores serve a storage function for nutrients and dilute waste-products or antimicrobials and thus should have a length/width ratio close to unity. The understanding provided here on the role of water in biofilms, can be employed to artificially engineer by-pass channels or additional pores in industrial and environmental biofilms to increase production yields or enhance antimicrobial penetration in infectious biofilms.
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Affiliation(s)
- Kecheng Quan
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands.,College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, P.R. China
| | - Jiapeng Hou
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
| | - Zexin Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, P.R. China
| | - Yijin Ren
- Department of Orthodontics, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
| | - Brandon W Peterson
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
| | - Hans-Curt Flemming
- Singapore Centre for Environmental Life Sciences/Engineering and the School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Faculty of Chemistry, Biofilm Centre, University of Duisburg-Essen, Essen, Germany
| | - Christian Mayer
- Faculty of Chemistry, Physical Chemistry, University of Duisburg-Essen, Essen, Germany
| | - Henk J Busscher
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
| | - Henny C van der Mei
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands
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16
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Pattem J, Davrandi M, Aguayo S, Slak B, Maev R, Allan E, Spratt D, Bozec L. Dependency of hydration and growth conditions on the mechanical properties of oral biofilms. Sci Rep 2021; 11:16234. [PMID: 34376751 PMCID: PMC8355335 DOI: 10.1038/s41598-021-95701-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 07/21/2021] [Indexed: 11/21/2022] Open
Abstract
Within the oral cavity, dental biofilms experience dynamic environments, in part due to changes in dietary content, frequency of intake and health conditions. This can impact bacterial diversity and morpho-mechanical properties. While phenotypic properties of oral biofilms are closely related to their composition, these can readily change according to dynamic variations in the growth environment and nutrient availability. Understanding the interlink between phenotypic properties, variable growth conditions, and community characterization is an essential requirement to develop structure–property relationships in oral-biofilms. In this study, the impact of two distinct growth media types with increasing richness on the properties of oral biofilms was assessed through a new combination of in-vitro time-lapse biophysical methods with microbiological assays. Oral biofilms grown in the enriched media composition presented a decrease in their pH, an increase in soluble EPS production, and a severe reduction in bacterial diversity. Additionally, enriched media conditions presented an increase in biofilm volumetric changes (upon hydration) as well as a reduction in elastic modulus upon indentation. With hydration time considered a major factor contributing to changes in biofilm mechanical properties, we have shown that it is less associated than media richness. Future investigations can now use this time-lapse approach, with a clearer focus on the extracellular matrix of oral biofilms dictating their morpho-mechanical properties.
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Affiliation(s)
- J Pattem
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK. .,National Centre for Molecular Hydrodynamics, and Soft Matter Biomaterials and Bio-Interfaces, University of Nottingham, The Limes Building, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD, UK.
| | - M Davrandi
- Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, London, UK
| | - S Aguayo
- School of Dentistry, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - B Slak
- Department of Electrical and Computer Engineering, University of Windsor, Windsor, Canada
| | - R Maev
- Department of Electrical and Computer Engineering, University of Windsor, Windsor, Canada
| | - E Allan
- Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, London, UK
| | - D Spratt
- Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, London, UK
| | - L Bozec
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK.,Faculty of Dentistry, University of Toronto, Toronto, Canada
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17
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Zabiegaj D, Hajirasouliha F, Duilio A, Guido S, Caserta S, Kostoglou M, Petala M, Karapantsios T, Trybala A. Wetting/spreading on porous media and on deformable, soluble structured substrates as a model system for studying the effect of morphology on biofilms wetting and for assessing anti-biofilm methods. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Pavissich JP, Li M, Nerenberg R. Spatial distribution of mechanical properties in Pseudomonas aeruginosa biofilms, and their potential impacts on biofilm deformation. Biotechnol Bioeng 2021; 118:1564-1575. [PMID: 33415727 DOI: 10.1002/bit.27671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/01/2021] [Accepted: 01/04/2021] [Indexed: 11/08/2022]
Abstract
The mechanical properties of biofilms can be used to predict biofilm deformation under external forces, for example, under fluid flow. We used magnetic tweezers to spatially map the compliance of Pseudomonas aeruginosa biofilms at the microscale, then applied modeling to assess its effects on biofilm deformation. Biofilms were grown in capillary flow cells with Reynolds numbers (Re) ranging from 0.28 to 13.9, bulk dissolved oxygen (DO) concentrations from 1 mg/L to 8 mg/L, and bulk calcium ion (Ca2+ ) concentrations of 0 and 100 mg CaCl2 /L. Higher Re numbers resulted in more uniform biofilm morphologies. The biofilm was stiffer at the center of the flow cell than near the walls. Lower bulk DO led to more stratified biofilms. Higher Ca2+ concentrations led to increased stiffness and more uniform mechanical properties. Using the experimental mechanical properties, fluid-structure interaction models predicted up to 64% greater deformation for heterogeneous biofilms, compared with a homogeneous biofilms with the same average properties. However, the deviation depended on the biofilm morphology and flow regime. Our results show significant spatial mechanical variability exists at the microscale, and that this variability can potentially affect biofilm deformation. The average biofilm mechanical properties, provided in many studies, should be used with caution when predicting biofilm deformation.
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Affiliation(s)
- Juan P Pavissich
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Santiago, Chile.,Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile.,Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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19
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Huang C, Sun PP, Won J, Wang Y, Boppart SA, Nguyen TH. Effect of Nonphosphorus Corrosion Inhibitors on Biofilm Pore Structure and Mechanical Properties. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14716-14724. [PMID: 33124800 PMCID: PMC7949192 DOI: 10.1021/acs.est.0c04645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Understanding the effects of biofilm structural and mechanical properties, which can influence biofilm cohesiveness and detachment under physical stress, is critical for biofilm and biofilm-associated pathogen control. In this study, we used optical coherence tomography (OCT) and nanoindentation to determine the role of silicate and tin (two experimental nonphosphate corrosion inhibitors) on the porous structure and stiffness of three types of multispecies biofilms. These biofilms were grown from groundwater (a drinking water source), and this groundwater was amended with either tin or silicate corrosion inhibitor (0.5 mg/L as Sn and 20 mg/L as SiO2). Based on the elastic moduli of these biofilms, tin biofilms and groundwater biofilms were the stiffest, followed by silicate biofilms. The thickness normalized by the growth time for silicate biofilms was highest at 38 ± 7.1 μm/month, compared to 21 ± 3.2 and 11 ± 2.4 μm/month for tin biofilms and groundwater biofilms, respectively. The silicate biofilms had the greatest overall porosities and were thickest among the three biofilms. Based on the pore network modeling (PNM) of OCT images, larger pores and connections were found in the silicate biofilms compared to those in tin and groundwater biofilms. Our analysis showed that the thicker and more porous biofilms (silicate biofilms) were potentially less resistant to deformation than the thinner and denser biofilms (tin and groundwater biofilms).
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Affiliation(s)
- Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Peter P Sun
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jungeun Won
- Departments of Electrical and Computer Engineering and Bioengineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yin Wang
- Department of Civil and Environmental Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States
| | - Stephen A Boppart
- Departments of Electrical and Computer Engineering and Bioengineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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20
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Affiliation(s)
- Irit Rosenhek‐Goldian
- Department of Chemical Research Support Weizmann Institute of Science Herzl 234 Rehovot ISRAEL
| | - Sidney R. Cohen
- Department of Chemical Research Support Weizmann Institute of Science Herzl 234 Rehovot ISRAEL
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21
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Monti D, Hubas C, Lourenço X, Begarin F, Haouisée A, Romana L, Lefrançois E, Jestin A, Budzinski H, Tapie N, Risser T, Mansot JL, Keith P, Gros O, Lopez PJ, Lauga B. Physical properties of epilithic river biofilm as a new lead to perform pollution bioassessments in overseas territories. Sci Rep 2020; 10:17309. [PMID: 33057038 PMCID: PMC7560750 DOI: 10.1038/s41598-020-73948-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 08/30/2020] [Indexed: 11/10/2022] Open
Abstract
Chlordecone (CLD) levels measured in the rivers of the French West Indies were among the highest values detected worldwide in freshwater ecosystems, and its contamination is recognised as a severe health, environmental, agricultural, economic, and social issue. In these tropical volcanic islands, rivers show strong originalities as simplified food webs, or numerous amphidromous migrating species, making the bioindication of contaminations a difficult issue. The objective of this study was to search for biological responses to CLD pollution in a spatially fixed and long-lasting component of the rivers in the West Indies: the epilithic biofilm. Physical properties were investigated through complementary analyses: friction, viscosity as well as surface adhesion were analyzed and coupled with measures of biofilm carbon content and exopolymeric substance (EPS) production. Our results have pointed out a mesoscale chemical and physical reactivity of the biofilm that can be correlated with CLD contamination. We were able to demonstrate that epilithic biofilm physical properties can effectively be used to infer freshwater environmental quality of French Antilles rivers. The friction coefficient is reactive to contamination and well correlated to carbon content and EPS production. Monitoring biofilm physical properties could offer many advantages to potential users in terms of effectiveness and ease of use, rather than more complex or time-consuming analyses.
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Affiliation(s)
- Dominique Monti
- UMR BOREA, UA-MNHN-SU-IRD-CNRS-UCN, Université des Antilles, BP 592, 97157, Pointe-à-Pitre, Guadeloupe, France.
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Université Des Antilles, MNHN, CNRS, SU, EPHE, BP 592, 97157, Pointe-à-Pitre, Guadeloupe, France.
| | - Cedric Hubas
- Muséum National D'Histoire Naturelle, UMR BOREA, MNHN-SU-IRD-CNRS-UCN-UA, Place de la croix, Station Marine de Concarneau, Concarneau, France
| | - Xavier Lourenço
- UMR BOREA, UA-MNHN-SU-IRD-CNRS-UCN, Université des Antilles, BP 592, 97157, Pointe-à-Pitre, Guadeloupe, France
| | - Farid Begarin
- C3MAG, UFR Des Sciences Exactes Et Naturelles, Université Des Antilles, BP 592, 97159, Pointe-à-Pitre, Guadeloupe, France
| | - Alexandre Haouisée
- UMR BOREA, UA-MNHN-SU-IRD-CNRS-UCN, Université des Antilles, BP 592, 97157, Pointe-à-Pitre, Guadeloupe, France
| | - Laurence Romana
- GTSI, département de Physique, Université des Antilles, BP 592, 97159, Pointe-à-Pitre Cedex, Guadeloupe, France
| | | | - Alexandra Jestin
- UPR 103 HORTSYS - CIRAD - Fonctionnement agroécologique Et Performances Des systèmes de Cultures Horticoles, Campus Agro-Environnemental Caraïbe, 97285, Le Lamentin, Martinique, France
| | - Hélène Budzinski
- UMR CNRS 5805 EPOC - OASU, Équipe LPTC, Université de Bordeaux, 351 Cours de la libération, 33405, Talence Cedex, France
| | - Nathalie Tapie
- UMR CNRS 5805 EPOC - OASU, Équipe LPTC, Université de Bordeaux, 351 Cours de la libération, 33405, Talence Cedex, France
| | - Théo Risser
- E2S UPPA, CNRS, IPREM, Universite de Pau Et Des Pays de L'Adour, BP 1155, 64013, Pau Cedex, France
| | - Jean-Louis Mansot
- C3MAG, UFR Des Sciences Exactes Et Naturelles, Université Des Antilles, BP 592, 97159, Pointe-à-Pitre, Guadeloupe, France
- GTSI, département de Physique, Université des Antilles, BP 592, 97159, Pointe-à-Pitre Cedex, Guadeloupe, France
| | - Philippe Keith
- Muséum National D'Histoire Naturelle, UMR BOREA, MNHN-SU-IRD-CNRS-UCN-UA, 57 rue Cuvier, CP26, 75231, Paris Cedex 05, France
| | - Olivier Gros
- C3MAG, UFR Des Sciences Exactes Et Naturelles, Université Des Antilles, BP 592, 97159, Pointe-à-Pitre, Guadeloupe, France
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Université Des Antilles, MNHN, CNRS, SU, EPHE, BP 592, 97157, Pointe-à-Pitre, Guadeloupe, France
| | - Pascal-Jean Lopez
- Muséum National D'Histoire Naturelle, UMR BOREA, MNHN-SU-IRD-CNRS-UCN-UA, 57 rue Cuvier, CP26, 75231, Paris Cedex 05, France
| | - Béatrice Lauga
- E2S UPPA, CNRS, IPREM, Universite de Pau Et Des Pays de L'Adour, BP 1155, 64013, Pau Cedex, France
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22
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Pandit S, Fazilati M, Gaska K, Derouiche A, Nypelö T, Mijakovic I, Kádár R. The Exo-Polysaccharide Component of Extracellular Matrix is Essential for the Viscoelastic Properties of Bacillus subtilis Biofilms. Int J Mol Sci 2020; 21:ijms21186755. [PMID: 32942569 PMCID: PMC7555405 DOI: 10.3390/ijms21186755] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 12/17/2022] Open
Abstract
Bacteria are known to form biofilms on various surfaces. Biofilms are multicellular aggregates, held together by an extracellular matrix, which is composed of biological polymers. Three principal components of the biofilm matrix are exopolysaccharides (EPS), proteins, and nucleic acids. The biofilm matrix is essential for biofilms to remain organized under mechanical stress. Thanks to their polymeric nature, biofilms exhibit both elastic and viscous mechanical characteristics; therefore, an accurate mechanical description needs to take into account their viscoelastic nature. Their viscoelastic properties, including during their growth dynamics, are crucial for biofilm survival in many environments, particularly during infection processes. How changes in the composition of the biofilm matrix affect viscoelasticity has not been thoroughly investigated. In this study, we used interfacial rheology to study the contribution of the EPS component of the matrix to viscoelasticity of Bacillus subtilis biofilms. Two strategies were used to specifically deplete the EPS component of the biofilm matrix, namely (i) treatment with sub-lethal doses of vitamin C and (ii) seamless inactivation of the eps operon responsible for biosynthesis of the EPS. In both cases, the obtained results suggest that the EPS component of the matrix is essential for maintaining the viscoelastic properties of bacterial biofilms during their growth. If the EPS component of the matrix is depleted, the mechanical stability of biofilms is compromised and the biofilms become more susceptible to eradication by mechanical stress.
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Affiliation(s)
- Santosh Pandit
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden; (S.P.); (A.D.)
| | - Mina Fazilati
- Department of Industrial and Materials Science, Chalmers University of Technology, 412 96 Göteborg, Sweden;
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden;
| | - Karolina Gaska
- Department of Aerospace Engineering, University of Bristol, Bristol BS8 1TR, UK;
| | - Abderahmane Derouiche
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden; (S.P.); (A.D.)
| | - Tiina Nypelö
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden;
- Wallenberg Wood Science Center, Chalmers, 412 96 Göteborg, Sweden
| | - Ivan Mijakovic
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden; (S.P.); (A.D.)
- Correspondence: (I.M.); (R.K.)
| | - Roland Kádár
- Department of Industrial and Materials Science, Chalmers University of Technology, 412 96 Göteborg, Sweden;
- Wallenberg Wood Science Center, Chalmers, 412 96 Göteborg, Sweden
- Correspondence: (I.M.); (R.K.)
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23
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Mataraci-Kara E, Ataman M, Yilmaz G, Ozbek-Celik B. Evaluation of antifungal and disinfectant-resistant Candida species isolated from hospital wastewater. Arch Microbiol 2020; 202:2543-2550. [DOI: 10.1007/s00203-020-01975-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/01/2020] [Accepted: 07/06/2020] [Indexed: 11/28/2022]
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24
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Kretschmer M, Lieleg O. Chelate chemistry governs ion-specific stiffening of Bacillus subtilis B-1 and Azotobacter vinelandii biofilms. Biomater Sci 2020; 8:1923-1933. [PMID: 32031543 DOI: 10.1039/c9bm01763a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Unwanted formation of bacterial biofilms can cause problems in both the medical sector and industrial settings. However, removing them from surfaces remains an ongoing challenge since biofilm bacteria efficiently protect themselves from external influences such as mechanical shear forces by embedding themselves into a matrix of extracellular polymeric substances. Here, we discuss microscopic principles, which are responsible for alterations in the viscoelastic properties of biofilms upon contact with metal ions. We suggest that it is a combination of mainly two parameters, that decides if biofilm stiffening occurs or not: the ion size and the detailed configuration of polyanionic macromolecules from the biofilm matrix. Our results provide new insights in the molecular mechanisms that govern the mechanical properties of biofilms. Also, they indicate that hydrogels comprising purified biopolymers can serve as suitable model systems to reproduce certain aspects of biofilm mechanics - provided that the correct biopolymer is chosen.
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Affiliation(s)
- Martin Kretschmer
- Munich School of Bioengineering and Department of Mechanical Engineering, Technical University of Munich, 85748 Garching, Germany.
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25
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Kundukad B, Udayakumar G, Grela E, Kaur D, Rice SA, Kjelleberg S, Doyle PS. Weak acids as an alternative anti-microbial therapy. Biofilm 2020; 2:100019. [PMID: 33447805 PMCID: PMC7798471 DOI: 10.1016/j.bioflm.2020.100019] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/27/2019] [Accepted: 01/06/2020] [Indexed: 12/19/2022] Open
Abstract
Weak acids such as acetic acid and N-acetyl cysteine (NAC) at pH less than their pKa can effectively eradicate biofilms due to their ability to penetrate the biofilm matrix and the cell membrane. However, the optimum conditions for their activity against drug resistant strains, and safety, need to be understood for their application to treat infections or to inactivate biofilms on hard surfaces. Here, we investigate the efficacy and optimum conditions at which weak acids can eradicate biofilms. We compared the efficacy of various mono and triprotic weak acids such as N-acetyl cysteine (NAC), acetic acid, formic acid and citric acid, in eradicating biofilms. We found that monoprotic weak acids/acid drugs can kill mucoid P. aeruginosa mucA biofilm bacteria provided the pH is less than their pKa, demonstrating that the extracellular biofilm matrix does not protect the bacteria from the activity of the weak acids. Triprotic acids, such as citric acid, kill biofilm bacteria at pH < pKa1. However, at a pH between pKa1 and pKa2, citric acid is effective in killing the bacteria at the core of biofilm microcolonies but does not kill the bacteria on the periphery. The efficacy of a monoprotic weak acid (NAC) and triprotic weak acid (citric acid) were tested on biofilms formed by Klebsiella pneumoniae KP1, Pseudomonas putida OUS82, Staphylococcus aureus 15981, P. aeruginosa DK1-NH57388A, a mucoid cystic fibrosis isolate and P. aeruginosa PA_D25, an antibiotic resistant strain. We showed that weak acids have a broad spectrum of activity against a wide range of bacteria, including antibiotic resistant bacteria. Further, we showed that a weak acid drug, NAC, can kill bacteria without being toxic to human cells, if its pH is maintained close to its pKa. Thus weak acids/weak acid drugs target antibiotic resistant bacteria and eradicate the persister cells in biofilms which are tolerant to other conventional methods of biofilm eradication.
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Affiliation(s)
- Binu Kundukad
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore
| | - Gayathri Udayakumar
- School of Life and Physical Sciences, PSB academy, La Trobe University, Australia
| | - Erin Grela
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Dhamanpreet Kaur
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore.,The ithree Institute, The University of Technology Sydney, Sydney, NSW, Australia
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore.,Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Patrick S Doyle
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore.,Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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26
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Sankaran J, Tan NJHJ, But KP, Cohen Y, Rice SA, Wohland T. Single microcolony diffusion analysis in Pseudomonas aeruginosa biofilms. NPJ Biofilms Microbiomes 2019; 5:35. [PMID: 31728202 PMCID: PMC6841743 DOI: 10.1038/s41522-019-0107-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 10/04/2019] [Indexed: 01/25/2023] Open
Abstract
The influence of the biofilm matrix on molecular diffusion is commonly hypothesized to be responsible for emergent characteristics of biofilms such as nutrient trapping, signal accumulation and antibiotic tolerance. Hence quantifying the molecular diffusion coefficient is important to determine whether there is an influence of biofilm microenvironment on the mobility of molecules. Here, we use single plane illumination microscopy fluorescence correlation spectroscopy (SPIM-FCS) to obtain 3D diffusion coefficient maps with micrometre spatial and millisecond temporal resolution of entire Pseudomonas aeruginosa microcolonies. We probed how molecular properties such as size and charge as well as biofilm properties such as microcolony size and depth influence diffusion of fluorescently labelled dextrans inside biofilms. The 2 MDa dextran showed uneven penetration and a reduction in diffusion coefficient suggesting that the biofilm acts as a molecular sieve. Its diffusion coefficient was negatively correlated with the size of the microcolony. Positively charged dextran molecules and positively charged antibiotic tobramycin preferentially partitioned into the biofilm and remained mobile inside the microcolony, albeit with a reduced diffusion coefficient. Lastly, we measured changes of diffusion upon induction of dispersal and detected an increase in diffusion coefficient inside the biofilm before any loss of biomass. Thus, the change in diffusion is a proxy to detect early stages of dispersal. Our work shows that 3D diffusion maps are very sensitive to physiological changes in biofilms, viz. dispersal. However, this study also shows that diffusion, as mediated by the biofilm matrix, does not account for the high level of antibiotic tolerance associated with biofilms.
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Affiliation(s)
- Jagadish Sankaran
- 1Department of Biological Sciences, National University of Singapore, 117558 Singapore, Singapore.,2Centre for BioImaging Sciences, National University of Singapore, 117557 Singapore, Singapore
| | - Nicholas J H J Tan
- 3Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551 Singapore, Singapore.,4School of Biological Sciences, Nanyang Technological University, 637551 Singapore, Singapore
| | - Ka Pui But
- 2Centre for BioImaging Sciences, National University of Singapore, 117557 Singapore, Singapore.,5Department of Chemistry, National University of Singapore, 117543 Singapore, Singapore
| | - Yehuda Cohen
- 3Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551 Singapore, Singapore.,4School of Biological Sciences, Nanyang Technological University, 637551 Singapore, Singapore
| | - Scott A Rice
- 3Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551 Singapore, Singapore.,4School of Biological Sciences, Nanyang Technological University, 637551 Singapore, Singapore.,6ithree Institute, University of Technology Sydney, Sydney, Australia
| | - Thorsten Wohland
- 1Department of Biological Sciences, National University of Singapore, 117558 Singapore, Singapore.,2Centre for BioImaging Sciences, National University of Singapore, 117557 Singapore, Singapore.,5Department of Chemistry, National University of Singapore, 117543 Singapore, Singapore
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A Dual-Species Biofilm with Emergent Mechanical and Protective Properties. J Bacteriol 2019; 201:JB.00670-18. [PMID: 30833350 DOI: 10.1128/jb.00670-18] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/23/2019] [Indexed: 12/14/2022] Open
Abstract
Many microbes coexist within biofilms, or multispecies communities of cells encased in an extracellular matrix. However, little is known about the microbe-microbe interactions relevant for creating these structures. In this study, we explored a striking dual-species biofilm between Bacillus subtilis and Pantoea agglomerans that exhibited characteristics that were not predictable from previous work examining monoculture biofilms. Coculture wrinkle formation required a P. agglomerans exopolysaccharide as well as the B. subtilis amyloid-like protein TasA. Unexpectedly, other B. subtilis matrix components essential for monoculture biofilm formation were not necessary for coculture wrinkling (e.g., the exopolysaccharide EPS, the hydrophobin BslA, and cell chaining). In addition, B. subtilis cell chaining prevented coculture wrinkling, even though chaining was previously associated with more robust monoculture biofilms. We also observed that increasing the relative proportion of P. agglomerans (which forms completely featureless monoculture colonies) increased coculture wrinkling. Using microscopy and rheology, we observed that these two bacteria assemble into an organized layered structure that reflects the physical properties of both monocultures. This partitioning into distinct regions negatively affected the survival of P. agglomerans while also serving as a protective mechanism in the presence of antibiotic stress. Taken together, these data indicate that studying cocultures is a productive avenue to identify novel mechanisms that drive the formation of structured microbial communities.IMPORTANCE In the environment, many microbes form biofilms. However, the interspecies interactions underlying bacterial coexistence within these biofilms remain understudied. Here, we mimic environmentally relevant biofilms by studying a dual-species biofilm formed between Bacillus subtilis and Pantoea agglomerans and subjecting the coculture to chemical and physical stressors that it may experience in the natural world. We determined that both bacteria contribute structural elements to the coculture, which is reflected in its overall viscoelastic behavior. Existence within the coculture can be either beneficial or detrimental depending on the context. Many of the features and determinants of the coculture biofilm appear distinct from those identified in monoculture biofilm studies, highlighting the importance of characterizing multispecies consortia to understand naturally occurring bacterial interactions.
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Wheeler JD, Secchi E, Rusconi R, Stocker R. Not Just Going with the Flow: The Effects of Fluid Flow on Bacteria and Plankton. Annu Rev Cell Dev Biol 2019; 35:213-237. [PMID: 31412210 DOI: 10.1146/annurev-cellbio-100818-125119] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microorganisms often live in habitats characterized by fluid flow, from lakes and oceans to soil and the human body. Bacteria and plankton experience a broad range of flows, from the chaotic motion characteristic of turbulence to smooth flows at boundaries and in confined environments. Flow creates forces and torques that affect the movement, behavior, and spatial distribution of microorganisms and shapes the chemical landscape on which they rely for nutrient acquisition and communication. Methodological advances and closer interactions between physicists and biologists have begun to reveal the importance of flow-microorganism interactions and the adaptations of microorganisms to flow. Here we review selected examples of such interactions from bacteria, phytoplankton, larvae, and zooplankton. We hope that this article will serve as a blueprint for a more in-depth consideration of the effects of flow in the biology of microorganisms and that this discussion will stimulate further multidisciplinary effort in understanding this important component of microorganism habitats.
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Affiliation(s)
- Jeanette D Wheeler
- Institute of Environmental Engineering, Department of Civil, Environmental, and Geomatic Engineering, ETH Zürich, 8093 Zürich, Switzerland;
| | - Eleonora Secchi
- Institute of Environmental Engineering, Department of Civil, Environmental, and Geomatic Engineering, ETH Zürich, 8093 Zürich, Switzerland;
| | - Roberto Rusconi
- Department of Biomedical Sciences, Humanitas University, 20090 Pieve Emanuele (MI), Italy.,Humanitas Clinical and Research Center-IRCCS, 20089 Rozzano (MI), Italy
| | - Roman Stocker
- Institute of Environmental Engineering, Department of Civil, Environmental, and Geomatic Engineering, ETH Zürich, 8093 Zürich, Switzerland;
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Cattò C, Cappitelli F. Testing Anti-Biofilm Polymeric Surfaces: Where to Start? Int J Mol Sci 2019; 20:E3794. [PMID: 31382580 PMCID: PMC6696330 DOI: 10.3390/ijms20153794] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022] Open
Abstract
Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.
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Affiliation(s)
- Cristina Cattò
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy
| | - Francesca Cappitelli
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
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30
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Abstract
Food and beverage industries operate their production units under stringent hygiene standards to verify high-quality products. However, the presence of biofilms can cause hygienic problems in the industries in the case of pathogenic organisms. Microorganisms can form biofilms, which are resistant to cleaning and disinfection. Microorganisms in biofilms are closely packed in a matrix that acts as a barrier to cleaning and disinfection. Biofilms are observed in processing equipment and open surfaces, resulting in food safety problems or weakening of production efficiency. This review provides a recap of the biofouling process, including the production mechanisms and control techniques of microbial adhesion. Microbial adhesion and colonization are the sine qua non of the establishment of bacterial pathogenesis and this report focuses on their prevention.
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31
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Jafari M, Derlon N, Desmond P, van Loosdrecht MCM, Morgenroth E, Picioreanu C. Biofilm compressibility in ultrafiltration: A relation between biofilm morphology, mechanics and hydraulic resistance. WATER RESEARCH 2019; 157:335-345. [PMID: 30965160 DOI: 10.1016/j.watres.2019.03.073] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/22/2019] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
Poroelastic fluid-structure interaction models were coupled to experimental data to determine the effects of biofilm spatial distribution of mechanical and hydraulic properties on the biofilm hydraulic resistance and compressibility in membrane filtration processes. Biofilms were cultivated on ultrafiltration membranes for 20 and 30 days under high (0.28 bar) and low (0.06 bar) transmembrane pressure (TMP), in dead-end filtration mode. Subsequently, biofilms were subjected to a compression/relaxation cycles by step-wise TMP changes. Structural deformation of biofilms during compression was observed in-situ using optical coherence tomography. Experimental results show that the observed increase in the biofilm hydraulic resistance during compression is not necessarily accompanied by a detectable biofilm thickness reduction. A dual-layer biofilm model with a dense base and porous top layer could explain these observed results. Because porosity controls indirectly the mechanical response of biofilms under compression, results could be described without assuming a gradient in mechanical properties within the biofilm. The biofilm surface roughness did not significantly influence the water flux in this study. However, the fraction of biofilm base layer directly exposed to bulk liquid could be a good indicator in the determination of water flux. The main implications of this study for the design and operation of low-pressure membrane systems (e.g., MF and UF with fouling layer being the main filtration resistance) lays in the selection of favorable operational TMP and biofilm morphology.
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Affiliation(s)
- Morez Jafari
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands.
| | - Nicolas Derlon
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
| | - Peter Desmond
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Cristian Picioreanu
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
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Di Pippo F, Di Gregorio L, Congestri R, Tandoi V, Rossetti S. Biofilm growth and control in cooling water industrial systems. FEMS Microbiol Ecol 2019; 94:4935158. [PMID: 29596620 DOI: 10.1093/femsec/fiy044] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/13/2018] [Indexed: 12/18/2022] Open
Abstract
Matrix-embedded, surface-attached microbial communities, known as biofilms, profusely colonise industrial cooling water systems, where the availability of nutrients and organic matter favours rapid microbial proliferation and their adhesion to surfaces in the evaporative fill material, heat exchangers, water reservoir and cooling water sections and pipelines. The extensive growth of biofilms can promote micro-biofouling and microbially induced corrosion (MIC) as well as pose health problems associated with the presence of pathogens like Legionella pneumophila. This review examines critically biofilm occurrence in cooling water systems and the main factors potentially affecting biofilm growth, biodiversity and structure. A broad evaluation of the most relevant biofilm monitoring and control strategies currently used or potentially useful in cooling water systems is also provided.
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Affiliation(s)
- F Di Pippo
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy.,CNR-IAMC, National Research Council, Institute for Coastal Marine Environment, Località Sa Mardini, Torregrande, 09170 Oristano, Italy
| | - L Di Gregorio
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy.,University of Rome Tor Vergata, Department of Biology, Via Cracovia 1, 00133 Rome, Italy
| | - R Congestri
- University of Rome Tor Vergata, Department of Biology, Via Cracovia 1, 00133 Rome, Italy
| | - V Tandoi
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy
| | - S Rossetti
- CNR-IRSA, National Research Council, Water Research Institute, Via Salaria Km 29.300, Monterotondo 00015, Rome, Italy
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33
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Černáková L, Light C, Salehi B, Rogel-Castillo C, Victoriano M, Martorell M, Sharifi-Rad J, Martins N, Rodrigues CF. Novel Therapies for Biofilm-Based Candida spp. Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1214:93-123. [DOI: 10.1007/5584_2019_400] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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34
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Jafari M, Desmond P, van Loosdrecht MCM, Derlon N, Morgenroth E, Picioreanu C. Effect of biofilm structural deformation on hydraulic resistance during ultrafiltration: A numerical and experimental study. WATER RESEARCH 2018; 145:375-387. [PMID: 30173098 DOI: 10.1016/j.watres.2018.08.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/14/2018] [Accepted: 08/18/2018] [Indexed: 06/08/2023]
Abstract
Biofilm formation in membrane systems negatively impacts the filtration system performances. This study evaluated how biofilm compression driven by permeate flow increases the hydraulic resistance and leads to reduction in permeate flux. We analysed the effect of biofilm compression on hydraulic resistance and permeate flux through computational models supported by experimental data. Biofilms with homogeneous surface structure were subjected to step-wise changes in flux and transmembrane pressure during compression and relaxation tests. Biofilm thickness under applied forces was measured non-invasively in-situ using optical coherence tomography (OCT). A numerical model of poroelasticity, which couples water flow through the biofilm with biofilm mechanics, was developed to correlate the structural deformation with biofilm hydraulics (permeability and resistance). The computational model enabled extracting mechanical and hydrological parameters corresponding to the experimental data. Homogeneous biofilms under elevated compression forces experienced a significant reduction in thickness while only a slight increase in resistance was observed. This shows that hydraulic resistance of homogeneous biofilms was affected more by permeability decrease due to pore closure than by a decrease in thickness. Both viscoelastic and elastoplastic models could describe well the permanent biofilm deformation. However, for biofilms under study, a simpler elastic model could also be used due to the small irreversible deformations. The elastic moduli fitting the measured data were in agreement with other reported values for biofilm under compression. Biofilm stiffening under larger flow-driven compression forces was observed and described numerically by correlating inversely the elastic modulus with biofilm porosity. The importance of this newly developed method lies in estimation of accurate biofilm mechanical parameters to be used in numerical models for both membrane filtration system and biofouling cleaning strategies. Such model can ultimately be used to identify optimal operating conditions for membrane system subjected to biofouling.
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Affiliation(s)
- Morez Jafari
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, The Netherlands.
| | - Peter Desmond
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, The Netherlands
| | - Nicolas Derlon
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Cristian Picioreanu
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, The Netherlands
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35
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Towards standardized mechanical characterization of microbial biofilms: analysis and critical review. NPJ Biofilms Microbiomes 2018; 4:17. [PMID: 30131867 PMCID: PMC6102240 DOI: 10.1038/s41522-018-0062-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 02/05/2023] Open
Abstract
Developing reliable anti-biofilm strategies or efficient biofilm-based bioprocesses strongly depends on having a clear understanding of the mechanisms underlying biofilm development, and knowledge of the relevant mechanical parameters describing microbial biofilm behavior. Many varied mechanical testing methods are available to assess these parameters. The mechanical properties thus identified can then be used to compare protocols such as antibiotic screening. However, the lack of standardization in both mechanical testing and the associated identification methods for a given microbiological goal remains a blind spot in the biofilm community. The pursuit of standardization is problematic, as biofilms are living structures, i.e., both complex and dynamic. Here, we review the main available methods for characterizing the mechanical properties of biofilms through the lens of the relationship linking experimental testing to the identification of mechanical parameters. We propose guidelines for characterizing biofilms according to microbiological objectives that will help the reader choose an appropriate test and a relevant identification method for measuring any given mechanical parameter. The use of a common methodology for the mechanical characterization of biofilms will enable reliable analysis and comparison of microbiological protocols needed for improvement of engineering process and screening.
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36
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Powell LC, Pritchard MF, Ferguson EL, Powell KA, Patel SU, Rye PD, Sakellakou SM, Buurma NJ, Brilliant CD, Copping JM, Menzies GE, Lewis PD, Hill KE, Thomas DW. Targeted disruption of the extracellular polymeric network of Pseudomonas aeruginosa biofilms by alginate oligosaccharides. NPJ Biofilms Microbiomes 2018; 4:13. [PMID: 29977590 PMCID: PMC6026129 DOI: 10.1038/s41522-018-0056-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 05/20/2018] [Accepted: 06/06/2018] [Indexed: 11/29/2022] Open
Abstract
Acquisition of a mucoid phenotype by Pseudomonas sp. in the lungs of cystic fibrosis (CF) patients, with subsequent over-production of extracellular polymeric substance (EPS), plays an important role in mediating the persistence of multi-drug resistant (MDR) infections. The ability of a low molecular weight (Mn = 3200 g mol−1) alginate oligomer (OligoG CF-5/20) to modify biofilm structure of mucoid Pseudomonas aeruginosa (NH57388A) was studied in vitro using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) with Texas Red (TxRd®)-labelled OligoG and EPS histochemical staining. Structural changes in treated biofilms were quantified using COMSTAT image-analysis software of CLSM z-stack images, and nanoparticle diffusion. Interactions between the oligomers, Ca2+ and DNA were studied using molecular dynamics (MD) simulations, Fourier transform infrared spectroscopy (FTIR) and isothermal titration calorimetry (ITC). Imaging demonstrated that OligoG treatment (≥0.5%) inhibited biofilm formation, revealing a significant reduction in both biomass and biofilm height (P < 0.05). TxRd®-labelled oligomers readily diffused into established (24 h) biofilms. OligoG treatment (≥2%) induced alterations in the EPS of established biofilms; significantly reducing the structural quantities of EPS polysaccharides, and extracellular (e)DNA (P < 0.05) with a corresponding increase in nanoparticle diffusion (P < 0.05) and antibiotic efficacy against established biofilms. ITC demonstrated an absence of rapid complex formation between DNA and OligoG and confirmed the interactions of OligoG with Ca2+ evident in FTIR and MD modelling. The ability of OligoG to diffuse into biofilms, potentiate antibiotic activity, disrupt DNA-Ca2+-DNA bridges and biofilm EPS matrix highlights its potential for the treatment of biofilm-related infections. Small carbohydrate molecules derived from marine algae show potential for inhibiting biofilm formation in multi-drug resistant infections. A research team led by Lydia Powell at Cardiff University, UK, investigated the action of carbohydrates called alginate oligosaccharides, composed of a small number of linked sugar molecules. The oligosaccharides modified and disrupted the structure of cultured biofilms of Pseudomonas aeruginosa, the cause of many serious drug resistant infections. This effect significantly inhibited the formation and maintenance of the biofilm state, which is known to be a crucial factor allowing the bacteria to resist drug treatment. Antibiotics proved more effective following the oligosaccharide intervention. The researchers uncovered key molecular details involved in the ability of the oligosaccharides to diffuse into and disrupt biofilms. The therapeutic potential of these small carbohydrates is currently being investigated in clinical trials.
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Affiliation(s)
- Lydia C Powell
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - Manon F Pritchard
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - Elaine L Ferguson
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - Kate A Powell
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - Shree U Patel
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | | | | | - Niklaas J Buurma
- 3Physical Organic Chemistry Centre, School of Chemistry, Cardiff University, Cardiff, UK
| | | | - Jack M Copping
- 4Respiratory Diagnostics Group, Swansea University, Swansea, UK
| | | | - Paul D Lewis
- 4Respiratory Diagnostics Group, Swansea University, Swansea, UK
| | - Katja E Hill
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
| | - David W Thomas
- 1Advanced Therapies Group, Cardiff University School of Dentistry, Heath Park, Cardiff, CF14 4XY UK
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37
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A Multi-scale Biophysical Approach to Develop Structure-Property Relationships in Oral Biofilms. Sci Rep 2018; 8:5691. [PMID: 29632310 PMCID: PMC5890245 DOI: 10.1038/s41598-018-23798-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/19/2018] [Indexed: 11/09/2022] Open
Abstract
Over the last 5–10 years, optical coherence tomography (OCT) and atomic force microscopy (AFM) have been individually applied to monitor the morphological and mechanical properties of various single-species biofilms respectively. This investigation looked to combine OCT and AFM as a multi-scale approach to understand the role sucrose concentration and age play in the morphological and mechanical properties of oral, microcosm biofilms, in-vitro. Biofilms with low (0.1% w/v) and high (5% w/v) sucrose concentrations were grown on hydroxyapatite (HAP) discs from pooled human saliva and incubated for 3 and 5 days. Distinct mesoscale features of biofilms such as regions of low and high extracellular polymeric substances (EPS) were identified through observations made by OCT. Mechanical analysis revealed increasing sucrose concentration decreased Young’s modulus and increased cantilever adhesion (p < 0.0001), relative to the biofilm. Increasing age was found to decrease adhesion only (p < 0.0001). This was due to mechanical interactions between the indenter and the biofilm increasing as a function of increased EPS content, due to increasing sucrose. An expected decrease in EPS cantilever contact decreased adhesion due to bacteria proliferation with biofilm age. The application OCT and AFM revealed new structure-property relationships in oral biofilms, unattainable if the techniques were used independently.
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38
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The Inoculation Method Could Impact the Outcome of Microbiological Experiments. Appl Environ Microbiol 2018; 84:AEM.02264-17. [PMID: 29269495 DOI: 10.1128/aem.02264-17] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 12/09/2017] [Indexed: 01/17/2023] Open
Abstract
For the past 150 years, bacteria have been investigated primarily in liquid batch cultures. Contrary to most expectations, these cultures are not homogeneous mixtures of single-cell bacteria, because free-floating bacterial aggregates eventually develop in most liquid batch cultures. These aggregates share characteristics with biofilms, such as increased antibiotic tolerance. We investigated how aggregates develop and what influences this development in liquid batch cultures of Pseudomonas aeruginosa We focused on how the method of inoculation affected aggregation by assessing aggregate frequency and size using confocal laser scanning microscopy. Several traditional methods of initiating an overnight bacterial culture, i.e., inoculation directly from frozen cultures, inoculation using agar-grown cells, or inoculation using cells grown in liquid cultures, were investigated. We discovered a direct link between the inoculation method and the size and frequency of biofilm aggregates in liquid batch cultures, with inoculation directly from a plate resulting in the most numerous and largest aggregates. These large aggregates had an overall impact on the cultures' subsequent tolerance toward tobramycin, indicating that the inoculation method has a profound impact on antibiotic tolerance. We also observed a mechanism whereby preformed aggregates recruited single cells from the surrounding culture in a "snowball effect," building up aggregated biomass in the culture. This recruitment was found to rely heavily on the exopolysaccharide Psl. Additionally, we found that both Escherichia coli and Staphylococcus aureus produced aggregates in liquid batch cultures. Our results stress the importance of inoculation consistency throughout experiments and the substantial impact aggregate development in liquid batch cultures may have on the outcomes of microbiological experiments.IMPORTANCE Pure liquid cultures are fundamental to the field of microbiological research. These cultures are normally thought of as homogeneous mixtures of single-cell bacteria; the present study shows that this is not always true. Bacteria may aggregate in these liquid cultures. The aggregation can be induced by the method chosen for inoculation. The presence of aggregates can significantly change the outcomes of experiments by altering the phenotype of the cultures. The study found a mechanism whereby preformed aggregates are able to recruit surrounding single cells in a form of snowball effect, creating more and larger aggregates in the cultures. Once formed, these aggregates are hard to remove. Aggregates in liquid cultures may be an immense unseen challenge for microbiologists.
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Suwarno SR, Huang W, Chew YMJ, Tan SHH, Trisno AE, Zhou Y. On-line biofilm strength detection in cross-flow membrane filtration systems. BIOFOULING 2018; 34:123-131. [PMID: 29268634 DOI: 10.1080/08927014.2017.1409892] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 11/20/2017] [Indexed: 06/07/2023]
Abstract
A fluid dynamic gauging (FDG) technique was used for on-line and in situ measurements of Pseudomonas aeruginosa PAO1 biofilm thickness and strength on flat sheet polyethersulphone membranes. The measurements are the first to be successfully conducted in a membrane cross-flow filtration system under constant permeation. In addition, FDG was used to demonstrate the removal behaviour of biofilms through local biofilm strength and removal energy estimation, which other conventional measurements such as flux and TMP cannot provide. The findings suggest that FDG can provide valuable additional information related to biofilm properties that have not been measured by other monitoring methods.
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Affiliation(s)
- Stanislaus Raditya Suwarno
- b Singapore Membrane Technology Centre, Nanyang Environment & Water Research Institute , Nanyang Technological University , Singapore
| | - Wenhai Huang
- a Advanced Environmental Biotechnology Centre , Nanyang Environment & Water Research Institute, Nanyang Technological University , Singapore
| | - Y M John Chew
- d Centre for Advanced Separations Engineering and Department of Chemical Engineering , University of Bath , Bath , UK
| | - Sio Hoong Henrich Tan
- c School of Civil & Environmental Engineering , Nanyang Technological University , Singapore
| | - Augustinus Elmer Trisno
- c School of Civil & Environmental Engineering , Nanyang Technological University , Singapore
| | - Yan Zhou
- a Advanced Environmental Biotechnology Centre , Nanyang Environment & Water Research Institute, Nanyang Technological University , Singapore
- c School of Civil & Environmental Engineering , Nanyang Technological University , Singapore
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Karampatzakis A, Song CZ, Allsopp LP, Filloux A, Rice SA, Cohen Y, Wohland T, Török P. Probing the internal micromechanical properties of Pseudomonas aeruginosa biofilms by Brillouin imaging. NPJ Biofilms Microbiomes 2017; 3:20. [PMID: 28900539 PMCID: PMC5591272 DOI: 10.1038/s41522-017-0028-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 12/17/2022] Open
Abstract
Biofilms are organised aggregates of bacteria that adhere to each other or surfaces. The matrix of extracellular polymeric substances that holds the cells together provides the mechanical stability of the biofilm. In this study, we have applied Brillouin microscopy, a technique that is capable of measuring mechanical properties of specimens on a micrometre scale based on the shift in frequency of light incident upon a sample due to thermal fluctuations, to investigate the micromechanical properties of an active, live Pseudomonas aeruginosa biofilm. Using this non-contact and label-free technique, we have extracted information about the internal stiffness of biofilms under continuous flow. No correlation with colony size was found when comparing the averages of Brillouin shifts of two-dimensional cross-sections of randomly selected colonies. However, when focusing on single colonies, we observed two distinct spatial patterns: in smaller colonies, stiffness increased towards their interior, indicating a more compact structure of the centre of the colony, whereas, larger (over 45 μm) colonies were found to have less stiff interiors. A specialized microscopy technique can monitor biofilm stiffness in a non-destructive manner, yielding insights into biofilm structure and development. The technique, called Brillouin imaging, uses changes in the frequency of light interacting with a substance to reveal fine detail about the material’s mechanical properties. Peter Török and colleagues at Imperial College London, with co-workers in Singapore, used Brillouin imaging to study biofilms of Pseudomonas aeruginosa bacteria at different stages in their life cycle. In young colonies, stiffness increased towards the interior of the biofilm, while mature colonies had less stiff interiors. The older biofilms may therefore have hollow interiors or may have been moving towards a phase of bacterial dispersal from the biofilm state. This non-disruptive method to study mechanical variations within and between living biofilms may help efforts to combat biofilms in clinical, environmental and industrial situations.
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Affiliation(s)
- A Karampatzakis
- Centre for BioImaging Sciences, National University of Singapore, Singapore, 117557 Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, 117557 Singapore.,Blackett Laboratory, Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2BZ United Kingdom
| | - C Z Song
- Blackett Laboratory, Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2BZ United Kingdom
| | - L P Allsopp
- Imperial College London, Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, South Kensington Campus, Flowers Building, SW7 2AZ London, United Kingdom
| | - A Filloux
- Imperial College London, Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, South Kensington Campus, Flowers Building, SW7 2AZ London, United Kingdom
| | - S A Rice
- Singapore Centre for Environmental Life Sciences Engineering and the School of Biological Sciences, Nanyang Technological University Singapore, Singapore, 637551 Singapore
| | - Y Cohen
- Singapore Centre for Environmental Life Sciences Engineering and the School of Biological Sciences, Nanyang Technological University Singapore, Singapore, 637551 Singapore
| | - T Wohland
- Centre for BioImaging Sciences, National University of Singapore, Singapore, 117557 Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, 117557 Singapore.,Department of Biological Sciences and Department of Chemistry, National University of Singapore, Singapore, 117346 Singapore
| | - P Török
- Blackett Laboratory, Department of Physics, Imperial College London, Prince Consort Road, London, SW7 2BZ United Kingdom
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Kundukad B, Schussman M, Yang K, Seviour T, Yang L, Rice SA, Kjelleberg S, Doyle PS. Mechanistic action of weak acid drugs on biofilms. Sci Rep 2017; 7:4783. [PMID: 28684849 PMCID: PMC5500524 DOI: 10.1038/s41598-017-05178-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/24/2017] [Indexed: 01/18/2023] Open
Abstract
Selective permeability of a biofilm matrix to some drugs has resulted in the development of drug tolerant bacteria. Here we studied the efficacy of a weak organic acid drug, N-acetyl-L-cysteine (NAC), on the eradication of biofilms formed by the mucoid strain of Pseudomonas aeruginosa and investigated the commonality of this drug with that of acetic acid. We showed that NAC and acetic acid at pH < pKa can penetrate the matrix and eventually kill 100% of the bacteria embedded in the biofilm. Once the bacteria are killed, the microcolonies swell in size and passively shed bacteria, suggesting that the bacteria act as crosslinkers within the extracellular matrix. Despite shedding of the bacteria, the remnant matrix remains intact and behaves as a pH-responsive hydrogel. These studies not only have implications for drug design but also offer a route to generate robust soft matter materials.
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Affiliation(s)
- Binu Kundukad
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore, Singapore
| | - Megan Schussman
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Kaiyuan Yang
- Department of Pharmacy, National University of Singapore, Singapore, Singapore
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Centre for Marine Bio-Innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW, Australia
| | - Patrick S Doyle
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore, Singapore.
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.
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Ferrando D, Ziemba C, Herzberg M. Revisiting interrelated effects of extracellular polysaccharides during biofouling of reverse osmosis membranes: Viscoelastic properties and biofilm enhanced osmotic pressure. J Memb Sci 2017. [DOI: 10.1016/j.memsci.2016.08.071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Anodic biofilms as the interphase for electroactive bacterial growth on carbon veil. Biointerphases 2016; 11:031013. [PMID: 27609094 DOI: 10.1116/1.4962264] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The structure and activity of electrochemically active biofilms (EABs) are usually investigated on flat electrodes. However, real world applications such as wastewater treatment and bioelectrosynthesis require tridimensional electrodes to increase surface area and facilitate EAB attachment. The structure and activity of thick EABs grown on high surface area electrodes are difficult to characterize with electrochemical and microscopy methods. Here, the authors adopt a stacked electrode configuration to simulate the high surface and the tridimensional structure of an electrode for large-scale EAB applications. Each layer of the stacked electrode is independently characterized using confocal laser scanning microscopy (CLSM) and digital image processing. Shewanella oneidensis MR-1 biofilm on stacked carbon veil electrodes is grown under constant oxidative potentials (0, +200, and +400 mV versus Ag/AgCl) until a stable current output is obtained. The textural, aerial, and volumetric parameters extracted from CLSM images allow tracking of the evolution of morphological properties within the stacked electrodes. The electrode layers facing the bulk liquid show higher biovolumes compared with the inner layer of the stack. The electrochemical performance of S. oneidensis MR-1 is directly linked to the overall biofilm volume as well as connectivity between cell clusters.
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Ferrando Chavez DL, Nejidat A, Herzberg M. Viscoelastic Properties of Extracellular Polymeric Substances Can Strongly Affect Their Washing Efficiency from Reverse Osmosis Membranes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9206-9213. [PMID: 27404109 DOI: 10.1021/acs.est.6b01458] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The role of the viscoelastic properties of biofouling layers in their removal from the membrane was studied. Model fouling layers of extracellular polymeric substances (EPS) originated from microbial biofilms of Pseudomonas aeruginosa PAO1 differentially expressing the Psl polysaccharide were used for controlled washing experiments of fouled RO membranes. In parallel, adsorption experiments and viscoelastic modeling of the EPS layers were conducted in a quartz crystal microbalance with dissipation (QCM-D). During the washing stage, as shear rate was elevated, significant differences in permeate flux recovery between the three different EPS layers were observed. According to the amount of organic carbon remained on the membrane after washing, the magnitude of Psl production provides elevated resistance of the EPS layer to shear stress. The highest flux recovery during the washing stage was observed for the EPS with no Psl. Psl was shown to elevate the layer's shear modulus and shear viscosity but had no effect on the EPS adhesion to the polyamide surface. We conclude that EPS retain on the membrane as a result of the layer viscoelastic properties. These results highlight an important relation between washing efficiency of fouling layers from membranes and their viscoelastic properties, in addition to their adhesion properties.
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Affiliation(s)
- Diana Lila Ferrando Chavez
- The Jacob Blaustein Institutes for Desert Research, Zuckerberg Institute for Water Research, The Albert Katz International School of Desert Studies, Ben Gurion University of the Negev , Sede Boqer Campus, Midreshet Ben Gurion 84990, Israel
| | - Ali Nejidat
- The Jacob Blaustein Institutes for Desert Research, Zuckerberg Institute for Water Research, The Albert Katz International School of Desert Studies, Ben Gurion University of the Negev , Sede Boqer Campus, Midreshet Ben Gurion 84990, Israel
| | - Moshe Herzberg
- The Jacob Blaustein Institutes for Desert Research, Zuckerberg Institute for Water Research, The Albert Katz International School of Desert Studies, Ben Gurion University of the Negev , Sede Boqer Campus, Midreshet Ben Gurion 84990, Israel
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