Fig. 8. Dependence of the controller’s performance on the culture medium.

a Resource availability in the cell can be perturbed both by introducing additional genes competing for ribosomes and changing the culture medium’s nutrient quality, both of which our controller is designed to counteract. b, c Dependence of the steady-state value of p_sens in an open- and closed-loop system, relative to that for an undisturbed cell in the default medium (i.e., c_dist = 0, σ = 0.5), on the disturbing gene’s concentration and the change in the medium’s nutrient quality. The dashed white lines mark the nutrient qualities considered in (d) and (e). d, e Dependence of the steady-state value of p_sens, relative to that for an undisturbed cell, on the disturbing gene’s concentration for media with low (σ = 0.25, standing for λ ≈ 0.566 h⁻¹ in the closed-loop case) and high (σ = 0.75, standing for λ ≈ 1.462 h⁻¹ in the closed-loop case) nutrient qualities. Note that the undisturbed sensor protein concentration $p_{sens}^0$ is calculated for c_dist = 0 and the current nutrient quality—that is, σ = 0.25 or σ = 0.75, as opposed to (b, c), where it was defined for σ = 0.5 in all cases. Unless specified otherwise, the simulation parameters for all panels are given in Supplementary Table 9, and the ODEs used to simulate the controller are Supplementary Eqs.(121)–(129) in Supplementary Note S4.4.1. Source data are provided as a Source Data file.