Figure 5. Community dynamics of bacteriocin producers in a structured environment.

Competitions between bacteriocin producers in a structured environment were tested (A, B) numerically and (C) empirically. (A) Snapshot of local competition between two bacteriocinogenic strains. One, u_A, dominates in some regions in space, while its competitor, u_B, dominates in others. These regions are separated by fronts that are moving further away from the dominant strain, u_B. Bacteriocin concentrations are higher near the fronts due to mutual induction. In (B), the winner of the pairwise competition was plotted for various values of the test strain induction, l _A, and sensitivity, γ₁. Blue indicates domination of strain A, u_A, and red indicates domination of its’ competitor u_B. (C) A static plate environment was initiated by randomly depositing 24 droplets from pure cultures of the colcinogenic strains ColA and ColK. The changing spatial pattern of the community was documented and the mean area of each strain’s coverage of the plate surface calculated. The aerial coverage of the strains was shown to remain invariable over time. Data points are average of two independent measurements and the bars represent the deviation from the average.