The intercellular genetic circuit is one of the most important designs in our project. It builds up a bridge between the three chassis and integrates the nutrient-related signals in the ternary system. As the initiator (or signal input), the nutrient response part plays an essential role in this intercellular genetic circuit.

To achieve an effective nutrient response, we created a part collection containing carbon starvation inducible promoters and corresponding fluorescence reporters. Three different mechanisms of nutrient response are used in this part collection (Figure 1). In conclusion, this part collection integrates the global nutrient signal and visualizes them with fluorescence. With this part collection, we present a strategy to quantify intracellular nutrient stress.

Figure 1. (A) RpoS-dependent activation under starvation conditions (B) CRP-dependent activation under starvation conditions (C) Fis-dependent inhibition under nutrient-rich conditions