Description of mechanical response including detachment using a novel particle model of biofilm/flow interaction

Alpkvist, Erik; Klapper, Isaac

doi:10.2166/wst.2007.267

Cited by 79 publications

(108 citation statements)

References 23 publications

(18 reference statements)

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“…(1999), Alpkvist and Klapper (2007a), and Duddu et al (2008) have shown the benefit of including the fluid-structure interaction between the biofilm and the surrounding fluid, which is an improvement over the simple model used here.…”

Section: Moving Interfacementioning

confidence: 91%

Modeling how soluble microbial products (SMP) support heterotrophic bacteria in autotroph-based biofilms

Merkey

Rittmann

Chopp

2009

Journal of Theoretical Biology

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Multi-species biofilm modeling has been used for many years to understand the interactions between species in different biofilm systems, but the complex symbiotic relationship between species is sometimes overlooked, because models do not always include all relevant species and components. In this paper, we develop and use a mathematical model to describe a model biofilm system that includes autotrophic and heterotrophic bacteria and the key products produced by the bacteria. The model combines the methods of earlier multi-species models with a multi-component biofilm model in order to explore the interaction between species via exchange of soluble microbial products (SMP). We show that multiple parameter sets are able to describe the findings of experimental studies, and that heterotrophs growing on autotrophically produced SMP may pursue either r-or K-strategies to sustain themselves when SMP is their only substrate. We also show that heterotrophs can colonize some distance from the autotrophs and still be sustained by autotrophically produced SMP. This work defines the feasible range of parameters for utilization of SMP by heterotrophs and the nature of the interactions between autotrophs and heterotrophs in multi-species, multi-component biofilms.

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Section: Moving Interfacementioning

confidence: 91%

Modeling how soluble microbial products (SMP) support heterotrophic bacteria in autotroph-based biofilms

Merkey

Rittmann

Chopp

2009

Journal of Theoretical Biology

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“…As a part of detailed studies of biofilm development, they investigated different constitutive equations for the EPS network, including two viscous and two viscoelastic models. Alpkvist & Klapper [40] simulated the mechanical response of biofilm, including detachment under fluid shear based on the immersed boundary method. The biofilm was discretized into a set of breakable springs, whose behaviour was assumed linear but could be extended to 'more sophisticated' behaviour.…”

Section: Introductionmentioning

confidence: 99%

Modelling mechanical characteristics of microbial biofilms by network theory

Ehret

Böl

2013

J. R. Soc. Interface.

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In this contribution, we present a constitutive model to describe the mechanical behaviour of microbial biofilms based on classical approaches in the continuum theory of polymer networks. Although the model is particularly developed for the well-studied biofilms formed by mucoid Pseudomonas aeruginosa strains, it could easily be adapted to other biofilms. The basic assumption behind the model is that the network of extracellular polymeric substances can be described as a superposition of worm-like chain networks, each connected by transient junctions of a certain lifetime. Several models that were applied to biofilms previously are included in the presented approach as special cases, and for small shear strains, the governing equations are those of four parallel Maxwell elements. Rheological data given in the literature are very adequately captured by the proposed model, and the simulated response for a series of compression tests at large strains is in good qualitative agreement with reported experimental behaviour.

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“…Although earlier reports suggested that LPS modulates bacterial cell compressibility and helps prevent catastrophic structural failure due to mechanical stress (1,52), no direct physical evidence of its involvement in these processes has yet been presented. Therefore, monitoring biofilm viscoelasticity is crucial for demonstrating how well biofilms resist stresses, due to, for instance, fluid shear and antimicrobial peptides (5,6). To date, quantitative data on how LPS affects viscoelastic properties of biofilms are lacking, and existing studies have merely focused on elasticity measurements (7,52).…”

mentioning

confidence: 99%

Differential Lipopolysaccharide Core Capping Leads to Quantitative and Correlated Modifications of Mechanical and Structural Properties in Pseudomonas aeruginosa Biofilms

Lau¹,

Lindhout²,

Beveridge³

et al. 2009

J Bacteriol

103

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Bacterial biofilms are responsible for the majority of all microbial infections and have profound impact on industrial and geochemical processes. While many studies documented phenotypic differentiation and gene regulation of biofilms, the importance of their structural and mechanical properties is poorly understood. Here we investigate how changes in lipopolysaccharide (LPS) core capping in Pseudomonas aeruginosa affect biofilm structure through modification of adhesive, cohesive, and viscoelastic properties at an early stage of biofilm development. Microbead force spectroscopy and atomic force microscopy were used to characterize P. aeruginosa biofilm interactions with either glass substrata or bacterial lawns. Using isogenic migA, wapR, and rmlC mutants with defined LPS characteristics, we observed significant changes in cell mechanical properties among these strains compared to wild-type strain PAO1. Specifically, truncation of core oligosaccharides enhanced both adhesive and cohesive forces by up to 10-fold, whereas changes in instantaneous elasticity were correlated with the presence of O antigen. Using confocal laser scanning microscopy to quantify biofilm structural changes with respect to differences in LPS core capping, we observed that textural parameters varied with adhesion or the inverse of cohesion, while areal and volumetric parameters were linked to adhesion, cohesion, or the balance between them. In conclusion, this report demonstrated for the first time that changes in LPS expression resulted in quantifiable cellular mechanical changes that were correlated with structural changes in bacterial biofilms. Thus, the interplay between architectural and functional properties may be an important contributor to bacterial community survival.Biofilms are sessile microbial communities growing on a surface or at an interface, often enmeshed in polymeric substances. Being the predominant mode of microbial growth in nature, bacterial biofilms are particularly problematic in the context of human health, accounting for up to 80% of all bacterial infections. In industrial processes, bacterial biofilms cause corrosion and biofouling, resulting in considerable loss of productivity. In the natural environment, biofilms play a role in modulating worldwide geochemical cycles. Given the impact of biofilms in these diverse areas, the need for developing effective strategies to control them is of paramount importance. Since bacterial cell surface structures are convenient targets for control agents, their roles in influencing biofilm function and architecture warrant in-depth investigations. To date, most studies of biofilms have focused on genetic regulation, phenotypic differentiation and their contribution to antibiotic resistance. In contrast, the mechanical and structural properties that link the genotypes to phenotypes of bacterial biofilms are not well understood and rarely studied in a quantitative and correlated manner.Pseudomonas aeruginosa is a gram-negative opportunistic pathogen implicated in serious infe...

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Description of mechanical response including detachment using a novel particle model of biofilm/flow interaction

Cited by 79 publications

References 23 publications

Modeling how soluble microbial products (SMP) support heterotrophic bacteria in autotroph-based biofilms

Modeling how soluble microbial products (SMP) support heterotrophic bacteria in autotroph-based biofilms

Modelling mechanical characteristics of microbial biofilms by network theory

Differential Lipopolysaccharide Core Capping Leads to Quantitative and Correlated Modifications of Mechanical and Structural Properties in Pseudomonas aeruginosa Biofilms

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