Emergent biofilm growth model utilizing autonomous agents

Authored by P D Schreuders, I B Tawney, P Ganeshan

Date Published: 2007

Sponsors: Joint Institute for Food Safety and Applied Nutrition (JIFSAN)

Platforms: NetLogo

Model Documentation: Other Narrative Flow charts

Model Code URLs: Model code not found

Abstract

The goal of this work was to develop a model for biofilm growth that relied on simple cell behaviors and then to observe how different factors, such as reproduction and nutrient diffusion, affect the biofilm structure. The biofilm growth model was based on a discrete model with autonomous agents and was developed using NetLogo, a cross platform agent-based parallel modeling and simulation environment. Rules were applied to individual bacteria agents to successfully produce a variety of 2-D biofilm growth patterns. By altering reproduction and nutrient diffusion factors to create reproduction and/or differsion limited conditions, where reproduction is an intrinsic factor and diffusion is an extrinsic factor, different resultant biofilm structures were observed. Under both diffusion and reproduction limited conditions, mushroom shapes were observed; if the conditions were neither diffusion nor reproduction limited, circular shapes were observed, with a blending of these shapes under either diffusion or reproduction limited conditions. Since both factors affected the biofilm structure, these results suggests that a combination of intrinsic and extrinsic factors and not either alone, produces the different growth patterns observed in biofilms. These results are consistent with images obtained using confocal microscopy of E. coli grown on a glass substrate and stained with propidium iodide and SYTO-16. Identification of the relationships between these factors has the potential to improve the modeling of biofilms and predicting the impact of biofilms on processes as diverse as biotechnology, water treatment, and food safety.
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