Difference between revisions of "Part:BBa K1895995"

Latest revision as of 19:15, 27 September 2016

Time delay device

As part of our [http://2016.igem.org/Team:Newcastle iGEM project] we wanted to engineer Escherichia coli to mimic one of the properties of a capacitor, the ability to accumulate and hold charge for some time before discharging. This part is a hypothetical design of a genetic system that mimics these properties.

An electrical capacitor accumulates charge whilst a voltage is applied and then discharges when the voltage stops being applied. For our system we make an analogy between the voltage signal and protein concentration. Whereas an electrical capacitor accumulates charge, a biological ‘capacitor’ would accumulate proteins. Like an electrical capacitor which has a maximum charge it can accumulate, there is a maximum protein concentration that can accumulate in the cell determined by its production and degradation rate. Once proteins stop being accumulated in the cell it ‘discharges’ by having these drive the production of an output signal.

In this construct we use L-arabinose to mimic a voltage signal. This is entirely for experimental purposes, there is no reason that this device cannot be modified to respond to an electrical signal, for example by exploiting the heat shock response of E. coli as designed [http://2016.igem.org/Team:Newcastle/Parts in our other parts] from 2016. Although in this case we show that protein’s can be accumulated there is no reason why actual charge, in the form of a potential difference could not be generated across the cell membrane. There are already examples of membrane potentials in biology, the most obvious being found in neurons. This is something that has been explored by iGEM teams in the past e.g., [http://2008.igem.org/Team:Cambridge Cambridge (2008)]. We hope that this part can mimick the charge-discharge cycle in biological cells through the use of repressor/inducer competition.

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