Computer simulation study of early bacterial biofilm development

Acemel, Rafael D.; Govantes, Fernando; Cuetos, Alejandro

doi:10.1038/s41598-018-23524-x

Cited by 40 publications

(93 citation statements)

References 28 publications

(31 reference statements)

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“…Mathematical modeling allows investigators to easily activate and deactivate different biofilm features to gain insight into their impact on the system [28,29]. Both discrete and continuum models have been developed and applied to biofilm systems, both with different advantages and disadvantages [30][31][32][33][34][35][36][37][38]. Continuum models treat bacteria, EPS and water as interacting continua, for each of which there is an associated continuous concentration and velocity field and related mass and momentum conservation equations [35][36][37][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

Mechanics of biofilms formed of bacteria with fimbriae appendages

Jin

Marshall

2020

PLoS ONE

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Gram-negative bacteria, as well as some Gram-positive bacteria, possess hair-like appendages known as fimbriae, which play an important role in adhesion of the bacteria to surfaces or to other bacteria. Unlike the sex pili or flagellum, the fimbriae are quite numerous, with of order 1000 fimbriae appendages per bacterial cell. In this paper, a recently developed hybrid model for bacterial biofilms is used to examine the role of fimbriae tension force on the mechanics of bacterial biofilms. Each bacterial cell is represented in this model by a spherocylindrical particle, which interact with each other through collision, adhesion, lubrication force, and fimbrial force. The bacterial cells absorb water and nutrients and produce extracellular polymeric substance (EPS). The flow of water and EPS, and nutrient diffusion within these substances, is computed using a continuum model that accounts for important effects such as osmotic pressure gradient, drag force on the bacterial cells, and viscous shear. The fimbrial force is modeled using an outer spherocylinder capsule around each cell, which can transmit tensile forces to neighboring cells with which the fimbriae capsule collides. We find that the biofilm structure during the growth process is dominated by a balance between outward drag force on the cells due to the EPS flow away from the bacterial colony and the inward tensile fimbrial force acting on chains of cells connected by adhesive fimbriae appendages. The fimbrial force also introduces a large rotational motion of the cells and disrupts cell alignment caused by viscous torque imposed by the EPS flow. The current paper characterizes the competing effects of EPS drag and fimbrial force using a series of computations with different values of the ratio of EPS to bacterial cell production rate and different numbers of fimbriae per cell.

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Section: Introductionmentioning

confidence: 99%

Mechanics of biofilms formed of bacteria with fimbriae appendages

Jin

Marshall

2020

PLoS ONE

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“…Antibacterial studies of graphene materials have mainly focused on modifying their chemistry, but the physiological state of bacteria as a factor in susceptibility was not investigated. Biofilm formation is regulated by genetic and environmental factors and occurs through several developmental stages (Acemel et al 2018). In each stage, the bacterial cells physiologically differ from cells in the other stages and biofilm cells may differ phenotypically from planktonic cells (Bester et al 2005).…”

Section: Resultsmentioning

confidence: 99%

Antibacterial effect of graphene oxide (GO) nano-particles against Pseudomonas putida biofilm of variable age

Fallatah

Elhaneid

Ali‐Boucetta

et al. 2019

Environ Sci Pollut Res

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Graphene oxide (GO) has been reported to possess antibacterial activity; therefore, its accumulation in the environment could affect microbial communities such as biofilms. The susceptibility of biofilms to antimicrobials is known to depend on the stage of biofilm maturity. The aim of this study was to investigate the effect of GO nano-particles on Pseudomonas putida KT2440 biofilm of variable age. FT-IR, UV-vis, and Raman spectroscopy confirmed the oxidation of graphene while XPS confirmed the high purity of the synthesised GO over 6 months. Biofilms varying in maturity (24, 48, and 72 h) were formed using a CDC reactor and were treated with GO (85 μg/mL or 8.5 μg/mL). The viability of P. putida was monitored by culture on media and the bacterial membrane integrity was assessed using flow cytometry. P. putida cells were observed using confocal microscopy and SEM. The results showed that GO significantly reduced the viability of 48-h biofilm and detached biofilm cells associated with membrane damage while the viability was not affected in 24- and 72-h biofilms and detached biofilm cells. The results showed that susceptibility of P. putida biofilm to GO varied according to age which may be due to changes in the physiological state of cells during maturation. Graphical abstract Electronic supplementary material The online version of this article (10.1007/s11356-019-05688-9) contains supplementary material, which is available to authorized users.

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“…Although several studies have focused on the biofilm’s mechanical properties under different conditions ( Towler et al, 2003 ; Acemel et al, 2018 ; Boudarel et al, 2018 ; Charlton et al, 2019 ; Jana et al, 2020 ), little is known about the role of the polymer matrix interactions on the mechanical stabilization of the biofilm and how they evolve along the growth of the biofilm under hydrodynamic stress. From a physical point of view, biofilms can be regarded as “living gels” that exhibit viscoelastic properties, wherein cells are active particles dispersed in a passive matrix ( Klapper et al, 2002 ; Wilking et al, 2011 ).…”

Section: Introductionmentioning

confidence: 99%

Self-Adaptation of Pseudomonas fluorescens Biofilms to Hydrodynamic Stress

et al. 2021

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In some conditions, bacteria self-organize into biofilms, supracellular structures made of a self-produced embedding matrix, mainly composed of polysaccharides, DNA, proteins, and lipids. It is known that bacteria change their colony/matrix ratio in the presence of external stimuli such as hydrodynamic stress. However, little is still known about the molecular mechanisms driving this self-adaptation. In this work, we monitor structural features of Pseudomonas fluorescens biofilms grown with and without hydrodynamic stress. Our measurements show that the hydrodynamic stress concomitantly increases the cell density population and the matrix production. At short growth timescales, the matrix mediates a weak cell-cell attractive interaction due to the depletion forces originated by the polymer constituents. Using a population dynamics model, we conclude that hydrodynamic stress causes a faster diffusion of nutrients and a higher incorporation of planktonic bacteria to the already formed microcolonies. This results in the formation of more mechanically stable biofilms due to an increase of the number of crosslinks, as shown by computer simulations. The mechanical stability also relies on a change in the chemical compositions of the matrix, which becomes enriched in carbohydrates, known to display adhering properties. Overall, we demonstrate that bacteria are capable of self-adapting to hostile hydrodynamic stress by tailoring the biofilm chemical composition, thus affecting both the mesoscale structure of the matrix and its viscoelastic properties that ultimately regulate the bacteria-polymer interactions.

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Computer simulation study of early bacterial biofilm development

Cited by 40 publications

References 28 publications

Mechanics of biofilms formed of bacteria with fimbriae appendages

Mechanics of biofilms formed of bacteria with fimbriae appendages

Antibacterial effect of graphene oxide (GO) nano-particles against Pseudomonas putida biofilm of variable age

Self-Adaptation of Pseudomonas fluorescens Biofilms to Hydrodynamic Stress

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