EXPERIMENTAL INVESTIGATION ON THE VALIDITY OF POPULATION-DYNAMICS APPROACH TO BACTERIAL COLONY FORMATION

We have investigated the dynamics of a two-dimensional spreading of a bacterial population in a surface environment. After point inoculation of flagellated bacteria (Bacillus subtilis) on nutrient-rich semi-sol id medium, the bacterial population grew up by multiplication and tran slocation of cells, and developed a homogeneous round colony. By compa ring experimental results with those of numerical simulations of the m odel equation, we found that this homogeneous population growth of bac teria is an actual manifestation of growth dynamics described by the F isher's equation.