Probing passive diffusion of flagellated and deflagellated Escherichia coli

Tavaddod, Sharareh; Charsooghi, Mohammad A.; Abdi, Farhad; Khalesifard, Hamid Reza; Golestanian, Ramin

doi:10.1140/epje/i2011-11016-9

Cited by 52 publications

(26 citation statements)

References 20 publications

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“…In case of thermal motion, D = 1 3 for a colloid in a fluid. Activity can cause larger rotational diffusion coefficients and, hence, smaller Δ, which has been confirmed experimentally for E. coli bacteria [6,[60][61][62] and Chlamydomonas reinhardtii cells [60].…”

Section: Conditional Probability Distribution Functionsupporting

confidence: 59%

Confined active Brownian particles: theoretical description of propulsion-induced accumulation

2018

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The stationary-state distribution function of confined active Brownian particles (ABPs) is analyzed by computer simulations and analytical calculations. We consider a radial harmonic as well as an anharmonic confinement potential. In the simulations, the ABP is propelled with a prescribed velocity along a body-fixed direction, which is changing in a diffusive manner. For the analytical approach, the Cartesian components of the propulsion velocity are assumed to change independently; active Ornstein-Uhlenbeck particle (AOUP). This results in very different velocity distribution functions. The analytical solution of the Fokker-Planck equation for an AOUP in a harmonic potential is presented and a conditional distribution function is provided for the radial particle distribution at a given magnitude of the propulsion velocity. This conditional probability distribution facilitates the description of the coupling of the spatial coordinate and propulsion, which yields activity-induced accumulation of particles. For the anharmonic potential, a probability distribution function is derived within the unified colored noise approximation. The comparison of the simulation results with theoretical predictions yields good agreement for large rotational diffusion coefficients, e.g. due to tumbling, even for large propulsion velocities (Péclet numbers). However, we find significant deviations already for moderate Péclet number, when the rotational diffusion coefficient is on the order of the thermal one.

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Section: Conditional Probability Distribution Functionsupporting

confidence: 59%

Confined active Brownian particles: theoretical description of propulsion-induced accumulation

2018

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“…Still, there is some probability that nonmotile filaments would eventually make intimate contact with the substrate, perhaps aided by thermal motion. This possibility may account for the slight increase in biomass attained by ΔmotB cells over ΔfliC cells, despite their ostensibly reduced translational diffusion, owing to the presence of flagella, which increase the effective hydrodynamic radius of the cells (41).…”

Section: Discussionmentioning

confidence: 99%

Bacterial flagella explore microscale hummocks and hollows to increase adhesion

Friedlander

Vlamakis

Kim

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

262

238

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Biofilms, surface-bound communities of microbes, are economically and medically important due to their pathogenic and obstructive properties. Among the numerous strategies to prevent bacterial adhesion and subsequent biofilm formation, surface topography was recently proposed as a highly nonspecific method that does not rely on small-molecule antibacterial compounds, which promote resistance. Here, we provide a detailed investigation of how the introduction of submicrometer crevices to a surface affects attachment of Escherichia coli. These crevices reduce substrate surface area available to the cell body but increase overall surface area. We have found that, during the first 2 h, adhesion to topographic surfaces is significantly reduced compared with flat controls, but this behavior abruptly reverses to significantly increased adhesion at longer exposures. We show that this reversal coincides with bacterially induced wetting transitions and that flagellar filaments aid in adhesion to these wetted topographic surfaces. We demonstrate that flagella are able to reach into crevices, access additional surface area, and produce a dense, fibrous network. Mutants lacking flagella show comparatively reduced adhesion. By varying substrate crevice sizes, we determine the conditions under which having flagella is most advantageous for adhesion. These findings strongly indicate that, in addition to their role in swimming motility, flagella are involved in attachment and can furthermore act as structural elements, enabling bacteria to overcome unfavorable surface topographies. This work contributes insights for the future design of antifouling surfaces and for improved understanding of bacterial behavior in native, structured environments. microbial adhesion | structured surfaces | bacterial appendages | surface texture | surface wetting T he attachment of bacteria to solid surfaces is the first step in the formation of biofilms-communities of sessile microbes surrounded by a polymeric matrix (1, 2). A growing appreciation of the ubiquity and importance of biofilms in medicine and industry has led to a proliferation of antiadhesion strategies that include chemical, biological, and physical approaches (3-12). Attempts to block biofilm formation must also take into account the rapid evolution of bacteria and their ability to resist many chemical assaults (13)(14)(15)(16)(17). By preventing adhesion in a manner that is nontoxic for the bacteria as well as for the application (e.g., medical implants), there is hope that we may reduce the costs associated with biofilm formation without imposing selective pressures for the development of antibiotic resistance. Physical strategies, particularly the use of rationally designed surface topographies, have gained attention recently as highly nonspecific methods for prevention of attachment without the use of antimicrobials (6,8,11,(18)(19)(20).Understanding how bacteria interact with surfaces that have roughness on the micrometer and submicrometer length scales (i.e., comparable with th...

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“…as in liquid medium. The spatial 178 heterogeneity then comes from the difference of diffusion rates, where bacteria, due to 179 their large size, have diffusion rates between ∼ 3 · 10 2 µm 2 /h and ∼ 7 · 10 2 µm 2 /h[38] 180 (assuming no chemotaxis). Since our lattice is resolved at a resolution of = 200 µm,181 we can approximate the bacteria as being effectively immotile since they diffuse on…”

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confidence: 99%

Sustainability of spatially distributed bacteria-phage systems

Eriksen

Mitarai

Sneppen

2018

Preprint

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Virulent phages can expose their bacterial hosts to devastating epidemics, in principle leading to a complete elimination of their hosts. Although experiments indeed confirm large reduction of susceptible bacteria, there are no reports of complete extinctions. We here address this phenomenon from the perspective of spatial organization of bacteria and how this can influence the final survival of them. By modeling the transient dynamics of bacteria and phages when they are introduced into an environment with finite resources, we quantify how time-delayed lysis, the spatial separation of initial bacterial positions, and the self-protection of bacteria growing in spherical colonies favor bacterial survival. This suggests that spatial structures on the millimeter and sub-millimeter scale plays an important role in maintaining microbial diversity. Author summaryFor virulent phage that invade a bacterial population, the mass-action kinetics predict extinction for a wide range of infection parameters. This is not found in experiments, where sensitive bacteria repeatedly are seen to survive the first epidemics of phage attack. To explain the transient survival of infected bacterial populations we develop a combination of local mass-action kinetics with lattice models. This model includes May 13, 2019 1/24 population dynamics, a latency time between phage infection and cell lysis, spatial separation with percolation of phages as well as colony level protection on the sub-millimeter scale. Our model is validated against recently published data on infected Escherichia Coli colonies. Introduction 1 Naturally occurring bacteria live in spatially structured habitats: in the soil [1, 2], in our 2 guts [3, 4], and in food products [5]. The spatial heterogeneity is in part generated by 3 the diversity of the microbial world [6], in part by clusters of food sources, and in part 4 caused by the fact that bacterial division leaves the offspring close to their "mother" 5 and thereby often form microcolonies [7-9]. The spatial heterogeneity may in turn 6 amplify itself through propagation of host specific phages, if these percolate devastating 7 infections through the parts of space with most homogeneous distribution of their 8 hosts [10]. 9 Traditionally, phage-bacteria ecosystems are modeled by generalized versions of the 10 classical Lotka-Volterra equations [11-20]. In its simplest form, such mass-action 11 equations predict sustained oscillations which becomes damped when one takes into 12 account resource limitations. In contrast to the oscillating lynx-hare systems from 13 macroscopic ecology [21], the microbial ecology experiments appear much more damped. 14 However, with realistic parameters for phage infections [22] and realistic bacterial 15 starting populations, the Lotka-Volterra type equations predict that an invading phage 16 typically cause a collapse of the bacterial population to less than one bacterium, i.e. 17 extinction. This is clearly not seen in microbial experiments. Rather, after an initial 18 collapse to a m...

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Probing passive diffusion of flagellated and deflagellated Escherichia coli

Cited by 52 publications

References 20 publications

Confined active Brownian particles: theoretical description of propulsion-induced accumulation

Confined active Brownian particles: theoretical description of propulsion-induced accumulation

Bacterial flagella explore microscale hummocks and hollows to increase adhesion

Sustainability of spatially distributed bacteria-phage systems

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