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.:: EducETH E. Coli - Biology Perspective ::.

.:: Introduction ::.

Our aim is to engineer a biological system which exhibits learning behavior, i.e. a system which can alter its behavior according to external stimuli.

We are interested in this as learning plays a major role in living organisms and machine learning has numerous applications in engineering - it is therefore a great interface between engineering and biology, with possible applications as exciting as biological memories. In our project we are constructing an E. coli strain which with help of an external chemical signal (AHL) is able to remember which of two chemical substances (aTc and IPTG) it has previously been exposed to. The system architecture is based on a toggle switch consisting of different repressor and activator proteins synthesized from promoters which subject to two different regulations.

In the first operation phase (learning), the system is exposed to one of the two chemicals (aTC and IPTG) and AHL is added, causing a steady system behavior. In the second phase (remembering), the chemicals are removed, but AHL allows the system to still maintain its state.

Finally, in the final phase (recognizing), the system is exposed to any of the two chemicals again. Its response, reported with 4 fluorescent proteins, differs according not only to which chemical the system is exposed to now, but also to if this chemical is the same that the system has already experienced (learning effect). Therefore, 4 possible system responses are possible: now exposed to aTc and have seen it before/ now exposed to aTc and have not seen it before/ now exposed to IPTG and have seen it before/ now exposed to IPTG and have not seen it before.

.:: Experiments ::.

.:: References ::.

.:: To Do ::.