CHEMOTACTIC-BASED ADAPTIVE SELF-ORGANIZATION DURING COLONIAL DEVELOPMENT

Bacterial colonies have developed sophisticated modes of cooperative b ehavior which enable them to respond to adverse growth conditions. It has been shown that such behavior can be manifested in the development of complex colonial patterns. Certain bacterial species exhibit forma tion of branching patterns during colony development. Here we present a generic model to describe such patterning of swimming (tumbling) bac teria on agar surfaces. The model incorporates: (1) food diffusion, (2 ) reproduction and sporulation of the cells, (3) movement of the bacte rial cells within a self-produced wetting fluid and (4) chemotactic si gnaling. As a plausible explanation for transitions between different branching morphologies, we propose an interplay between chemotaxis tow ards food, self-produced short range chemoattractant and long range ch emorepellent.