Enhancement of Bacterial Motility due to Speed-Dependent Absorption

C.A. CONDAT; M.E. DI SALVO; G.J. SIBONA

Boston, EEUU

Congreso; 53rd Annual Meeting Biophysical Society; 2009

Biophysical American Society

Marine microorganisms often reach high swimming speeds, either to take advantage of evanescent nutrient patches or to beat Brownian forces. Since this implies that a sizable part of their energetic budget must be allocated to motion, it is reasonable to assume that some organisms are able to increase their nutrient intake by increasing their speed v. We formulate a model to investigate this hypothesis. We postulate that the nutrient absorption rate is of the form q(v) = q0 +Av, with q0 and A being constants. We find the steady state solutions and analyze their stability and the influence of thermal noise. Evaluations obtained using realistic parameter values indicate that the speed increase due to the enhanced nutrient absorption may be substantial. We also investigate how the microorganism’s dynamics can be influenced by the speed dependence transformation rate from the stored energy to kinetic energy. The description of the motion is further clarified by the use of the Fokker-Planck formalism and simulations.