Extrinsic noise effects on steady state protein levels: perception to discrete signal changes.

<p>Output from system (1)–(6) subject to discrete steps in signal level/perception computed using the Gillespie SSA. For comparison, the DegU levels predicted by the deterministic system with the response for the chosen values indicated by the red, blue, green and yellow dots, respectively, are shown in (A). Histograms show the levels of (B) DegU and (C) exoprotease collated from 1000 simulations at hours. All parameter values from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038574#pone-0038574-t001" target="_blank">Table 1</a> except for each simulation, was selected randomly from the values: (red); (blue); (green); (yellow). Initial levels set to correspond to the deterministic steady state associated with the midpoint values.