A simulation approach to the stochastic growth of bacterial towers is presented, in which a non-uniform and finite nutrient supply essentially determines the emerging structure through elementary chemotaxis. The method is based on cellular automata and we use simple, microscopic, local rules for bacterial division in nutrient-rich surroundings. Stochastic nutrient diffusion, while not crucial to the dynamics of the total population, is influential in determining the porosity of the bacterial tower and the roughness of its surface. As the bacteria run out of food, we observe an exponentially rapid saturation to a carrying capacity distribution, similar in many respects to that found in a recently proposed phenomenological hierarchical population model, which uses heuristic parameters and macroscopic rules. Complementary to that phenomenological model, the simulation aims at giving more microscopic insight into the possible mechanisms for one of the recently much studied bacterial morphotypes, known as "towering biofilm", observed experimentally using confocal laser microscopy. A simulation suggesting a mechanism for biofilm resistance to antibiotics is also shown.
|Number of pages||13|
|Journal||Physica A: Statistical Mechanics and its Applications|
|Early online date||6 Feb 2004|
|Publication status||Published - 1 May 2004|
|Event||Proceedings of the XVIII Max Born Symposium at Statistical Physics - Ladek Zdroj, Poland|
Duration: 22 Sept 2003 → 25 Sept 2003
Bibliographical noteThis research was supported by the Flemish Programe FWO-G.0222.02 “Physical and interdisciplinary applications of novel fractal structures”. We thank Katarzyna Sznajd-Weron and Jan Żebrowski for useful discussions.