Quantifying the Integration of Quorum-Sensing Signals with Single-Cell Resolution (original) (raw)
Figure 3
Autoinducer Dose Responses of V. harveyi Sensor Mutants
(A) Dose responses of LuxN+ cells to AI-1 (blue) and LuxPQ+ cells to AI-2 (red). Each average and standard deviation (error bar) of normalized GFP was obtained from microscopy images of 100 cells. Curves were fitted using αAI + βAI(1 + [AI]/_K_AI) with αAI-1 = 0.07, βAI-1 = 2.9, _K_AI-1 = 6.9 nM and αAI-2 = 0.09, βAI-2 = 1.9, _K_AI-2 = 6.4 nM. A.U. denotes arbitrary units.
(B) Dose responses of LuxN+ LuxPQ+ cells to either AI-1 (blue) or AI-2 (red) while the other autoinducer is either absent (open squares and circles) or present at a saturating concentration (solid squares and circles). Data in yellow-green represent the response to approximately equal amounts of AI-1 and AI-2 (_x_-axis values indicate total autoinducer concentrations).
(C) Dose–response surface of LuxN+ LuxPQ+ cells to various combinations of AI-1 and AI-2. Each vertex of the grid is the averaged normalized GFP fluorescence intensity obtained from a population of 100 cells exposed to the specified AI-1 and AI-2 concentrations. The dose–response curves in (B) correspond to cuts through this surface.
(D) The response of LuxN+ LuxPQ+ cells to combined AI-1 and AI-2 shown in (C) can be well described by a simple additive model γ0 + γAI−1/(1 + [AI-1]/_K_AI-1) + γAI-2/(1 + [AI-2]/_K_AI-2), with γ0 = 0.16, γAI-1 = 1.53, γAI-2 = 1.49, _K_AI-1 = 6.9 nM, _K_AI-2 = 6.4 nM. The red line has a slope equal to one.