An Integrated Modeling and Experimental Approach to Study the Influence of Environmental Nutrients on Biofilm Formation of Pseudomonas aeruginosa

Figure 1

An illustrative example to show the proposed approach for quantifying biofilm formation of P. aeruginosa for different availabilities of a specific nutrient component. The availability of the target nutrient component is represented by its maximum uptake rate in the flux balance analysis. A large uptake rate is used for the abundant nutrient condition, while a small uptake rate is assigned for the starving nutrient (a). The fluxes of those biofilm-associated reactions are then sampled for both reference and changed nutrient conditions and represented as flux distributions (b). The horizontal axe represents the metabolic fluxes through the th biofilm-associated reactions, that is, , while the vertical axe represents the occurrence probability of a specific metabolic flux. Upon the change of the nutrient availability from the reference to changed condition, the change of fluxes through each biofilm-associated reaction is quantified, which is then used to obtain the flux-change curve over all biofilm-associated reactions (c). Finally, the flux change curve is used to quantify biofilm formation capability of P. aeruginosa (d). In particular, a large flux increase in most biofilm-associated reactions indicates a high trend to form more P. aeruginosa biofilm. The metabolic reactions with large flux change during the biofilm formation were further identified, as they may imply the mechanisms used by P. aeruginosa to form a biofilm (e).