We are engineering our E. coli cells to process the correlation information of two enviornmental signal, similar to the process of conditioning in higher orgamisms. We have constructed and tested a series of AND gates which can sense the two signals: the conditioned and unconditioned stimuli. With the presence of both signals, the AND gate outputs a repressor protein and then changes the state of the bistable switch, which acts as a memory module. In this way, our E. coli cells can convert the information about the concurrence of the two signals into its memory. After the memory module is switched and given the "conditioned stimulus", the E. coli cells will pass the information to the reporter module and thus exhibit the "conditioned response."
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