Part:BBa_K3081051

Quorum Sensing CRISPRri System Enables Spatial-level Growth Control and Ultrasensitive Autoregulation of Growth

Based on the well-characterized growth control system, we constructed a quorum sensing CRISPRri system (qs-CRISPRri) to realize smart regulation of bacterial overall states. At first, we use GFP as the output to test our system.

We used different concentration of IPTG to regulate the expression level of LuxI. Grown cultures were induced by different concentration of IPTG in M9 medium for 6hours. And we used flow cytometry to measure the single bacterium’s GFP expression level (Figure.1). The cells’ expression level is positively related to the concentration of IPTG.

Figure 1.Characterization of the quorum sensing system

And we also measured the relationship between OD and GFP expression. We found that a positive correlation between GFP production per cell mass (FI/OD600) and population density (OD600) was remarkable(Figure 2).

Figure 2.Relation between GFP production and cell density of bacteria transformed with quorum sensing GFP system.

Reference:

[1]Weiqian Zeng, et al. Rational Design of an Ultrasensitive Quorum-Sensing Switch. ACS Synthetic Biology 2017 6 (8), 1445-1452.

[2]Y. Soma, T. Hanai. Self-induced metabolic state switching by a tunable cell density sensor for microbial isopropanol production. Metabolic Engineering 30 (2015) 7–158.