Development of the Pseudomonas aeruginosa mushroom morphology and cavity formation by iron-starvation: A mathematical modeling study

Miller, Judy Z.; Badawy, Hope T.; Clemons, C. B.; Kreider, K. L.; Wilber, Pat; Milsted, Amy; Young, G. W.

doi:10.1016/j.jtbi.2012.05.029

Cited by 12 publications

(12 citation statements)

References 47 publications

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“…Fully mature P. aeruginosa biofilms conceptually appear as mushroom‐shaped projections extending away from the surface (Figure c) with a texture characterized by channels and caverns [ Klausen et al ., , ; Miller et al ., ]. This morphology assumes unrestricted growth space and is similar to the pore‐filling form in our model.…”

Section: Discussionmentioning

confidence: 87%

Mechanistic models of biofilm growth in porous media

et al. 2014

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Nondestructive acoustics methods can be used to monitor in situ biofilm growth in porous media. In practice, however, acoustic methods remain underutilized due to the lack of models that can translate acoustic data into rock properties in the context of biofilm. In this paper we present mechanistic models of biofilm growth in porous media. The models are used to quantitatively interpret arrival times and amplitudes recorded in the 29 day long Davis et al. (2010) physical scale biostimulation experiment in terms of biofilm morphologies and saturation. The model pivots on addressing the sediment elastic behavior using the lower Hashin-Shtrikman bounds for grain mixing and Gassmann substitution for fluid saturation. The time-lapse P wave velocity (V P ; a function of arrival times) is explained by a combination of two rock models (morphologies); "load bearing" which assumes the biofilm as an additional mineral in the rock matrix and "pore filling" which assumes the biofilm as an additional fluid phase in the pores. The time-lapse attenuation (Q P À1; a function of amplitudes), on the other hand, can be explained adequately in two ways; first, through squirt flow where energy is lost from relative motion between rock matrix and pore fluid, and second, through an empirical function of porosity (ϕ), permeability (κ), and grain size. The squirt flow model-fitting results in higher internal ϕ (7% versus 5%) and more oblate pores (0.33 versus 0.67 aspect ratio) for the load-bearing morphology versus the pore-filling morphology. The empirical model-fitting results in up to 10% increase in κ at the initial stages of the load-bearing morphology. The two morphologies which exhibit distinct mechanical and hydraulic behavior could be a function of pore throat size. The biofilm mechanistic models developed in this study can be used for the interpretation of seismic data critical for the evaluation of biobarriers in bioremediation, microbial enhanced oil recovery, and CO 2 sequestration.

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Section: Discussionmentioning

confidence: 87%

Mechanistic models of biofilm growth in porous media

et al. 2014

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“…Several mathematical models have been developed to study bacterial colonies and biofilms from different aspects. These topics range from population dynamics 18 19 and morphological development 20 21 22 23 24 25 to the evolutionary interactions of bacterial species 26 27 28 29 , as well as treatment of bacterial biofilms 30 . The mathematical approaches in use include continuum models 22 25 26 30 31 as well as discrete (cell-based) models in two dimensions (2D) 19 20 21 28 29 32 or three dimensions (3D) 18 23 24 .…”

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confidence: 99%

Inoculation density and nutrient level determine the formation of mushroom-shaped structures in Pseudomonas aeruginosa biofilms

Ghanbari

Dehghany

Schwebs

et al. 2016

Sci Rep

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Pseudomonas aeruginosa often colonises immunocompromised patients and the lungs of cystic fibrosis patients. It exhibits resistance to many antibiotics by forming biofilms, which makes it hard to eliminate. P. aeruginosa biofilms form mushroom-shaped structures under certain circumstances. Bacterial motility and the environment affect the eventual mushroom morphology. This study provides an agent-based model for the bacterial dynamics and interactions influencing bacterial biofilm shape. Cell motility in the model relies on recently published experimental data. Our simulations show colony formation by immotile cells. Motile cells escape from a single colony by nutrient chemotaxis and hence no mushroom shape develops. A high number density of non-motile colonies leads to migration of motile cells onto the top of the colonies and formation of mushroom-shaped structures. This model proposes that the formation of mushroom-shaped structures can be predicted by parameters at the time of bacteria inoculation. Depending on nutrient levels and the initial number density of stalks, mushroom-shaped structures only form in a restricted regime. This opens the possibility of early manipulation of spatial pattern formation in bacterial colonies, using environmental factors.

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“…This phenomenon has been particularly well established for P. aeruginosa, a common soil bacterium [28] and opportunistic pathogen that thrives in open wounds [29,30], on subepithelial medical devices [31], and in the lungs of cystic fibrosis patients [32][33][34][35][36]. Under laminar flow 50 in simple microfluidic channels, P. aeruginosa forms biofilms with intermittent mushroom-shaped tower structures [32,[37][38][39]. Under irregular flow regimes in more complex environments, however, P. aeruginosa also produces sieve-like biofilm streamers that protrude into the liquid phase above the substratum [40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Flow environment and matrix structure interact to determine spatial competition inPseudomonas aeruginosabiofilms

Nadell

Ricaurte

Yan

et al. 2016

Preprint

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Bacteria often live in biofilms, which are microbial communities surrounded by a secreted extracellular matrix. Here, we demonstrate that hydrodynamic flow and matrix organization interact to shape competitive dynamics in Pseudomonas aeruginosa biofilms. Irrespective of initial frequency, in 15 competition with matrix mutants, wild type cells always increase in relative abundance in straighttunnel microfluidic devices under simple flow regimes. By contrast, in microenvironments with complex, irregular flow profiles -which are common in natural environments -wild type matrixproducing and isogenic non-producing strains can coexist. This result stems from local obstruction of flow by wild-type matrix producers, which generates regions of near-zero flow speed that allow matrix 20 mutants to locally accumulate. Our findings connect the evolutionary stability of matrix production with the hydrodynamics and spatial structure of the surrounding environment, providing a potential explanation for the variation in biofilm matrix secretion observed among bacteria in natural environments. 25

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Development of the Pseudomonas aeruginosa mushroom morphology and cavity formation by iron-starvation: A mathematical modeling study

Cited by 12 publications

References 47 publications

Mechanistic models of biofilm growth in porous media

Mechanistic models of biofilm growth in porous media

Inoculation density and nutrient level determine the formation of mushroom-shaped structures in Pseudomonas aeruginosa biofilms

Flow environment and matrix structure interact to determine spatial competition inPseudomonas aeruginosabiofilms

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