Transfer Curve Models For Synthetic Ahl-Receiver Devices

The input-output function of the AHL-receiver devices was determined by fitting cell fluorescence data with the following four-parameter logistical curve model: GFP = b + ( a-b ) / 1 +10^( ( log(EC50)-log([AHL]) )*h) where <em>a</em> is the maximal GFP output, <em>b</em> is the basal GFP output, <em>[AHL]</em> is the AHL inducer concentration, <em>GFP</em> is the green fluorescence response of the device for that inducer concentration, <em>EC50</em> is the inducer concentration that results in half maximal activation of the device, and <em>h</em> is proportional to the value of the steepest slope along the curve (Hill coefficient) that indicates the responsiveness of the device to the input.