Adaptation time and fold-change detection.

<p>(a) Adaptation time of the one-component model in response to a positive step of increasing size for different relative receptor lengths (from 0 mM to 0.1, 0.5, 1, 2, 3, 5 mM). (inset) Experimental adaptation-time data from bacterial chemotaxis (BC, tumble bias from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003300#pcbi-1003300-g002" target="_blank">Fig. 2</a> of <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003300#pcbi.1003300-Min1" target="_blank">[31]</a>), <i>Dictyostelium</i> (DC, adenylyl cyclase ACA from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003300#pcbi-1003300-g004" target="_blank">Fig. 4C</a> of <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003300#pcbi.1003300-Brzostowski1" target="_blank">[25]</a>), photo-transduction (PT, transmembrane current from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003300#pcbi-1003300-g006" target="_blank">Fig. 6B</a> of <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003300#pcbi.1003300-Forti1" target="_blank">[48]</a>), olfactory-transduction (OT, transmembrane current from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003300#pcbi-1003300-g001" target="_blank">Fig. 1a</a> of <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003300#pcbi.1003300-Menini1" target="_blank">[27]</a>). (b) Adaptation time of the one-component model in response to a negative step of increasing step size (same concentrations as in (a)). (inset) Comparison with the experimental BC data. (c–d) Input concentration (c) and activity (d) for a step from 0.1 to 0.5 mM (gray line) and a step from 0.2 to 1 mM (black dashed line). Although the input concentration is doubled, the two activity profiles superimpose almost exactly.