Team:NCTU Formosa/Project/Introduction

Our team constructed a controllable synthetic genetic circuit in Escherichia coli which has timer and counter functions. The circuit works as an OR gate to integrate temporal and environmental signals.

The output (red fluorescent protein: RFP) of the OR gate is ON when one of the input signals is ON. The timer function is controlled by Lac promoter, and the concentration of lactose determines timer’s working length. After E.coli consume the added lactose, the RFP will be translated to remind us that time’s up.

The counter function can detect the bacteria population with LuxI/LuxR device; Moreover, the counter sensitivity is controlled by the strength of TetR repressible promoter. If external bacteria invade the system, the extra AHL produced by them will induce the RFP translation to warn us the contamination. Our project can be applied to storage warning signs of fresh food, contact lens, and wound dressing.