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BP: Fachverband Biologische Physik
BP 22: Bacterial Biophysics II
BP 22.7: Vortrag
Mittwoch, 20. März 2024, 16:45–17:00, H 0112
Sensory adaptation in a continuum model of bacterial chemotaxis - working range, cost-accuracy relation, and coupled systems — •Vansh Kharbanda1,2 and Benedikt Sabass1,2 — 1Department of Veterinary Sciences, LMU München — 2Department of Physics, LMU München
Sensory adaptation enables organisms to adjust their perception in a changing environment. A paradigm is bacterial chemotaxis, where the output activity of chemoreceptors is adapted to distinct baseline concentrations via methylation. The range of internal receptor states limits the stimulus magnitude to which these systems can adapt. Here, we use a highly idealized, Langevin-equation based model to study how the finite range of state variables affects the adaptation accuracy and the energy dissipation in individual and coupled systems. Maintaining an adaptive state requires energy dissipation. We show that the steady-state dissipation rate increases approximately linearly with the adaptation accuracy for varying stimulus magnitudes in the so-called fully adaptative state. This result complements the well-known logarithmic cost-accuracy relationship for varying chemical driving. Next, we study linearly coupled pairs of sensory units. We find that the interaction reduces the dissipation rate per unit and affects the overall cost-accuracy relationship. A coupling of the slow methylation variables results in a better accuracy than a coupling of activities. Overall, the findings highlight the significance of both the working range and collective operation mode as crucial design factors that impact the accuracy and energy expenditure of molecular adaptation networks.
Keywords: Chemotaxis; Langevin equation; Entropy production rate