Constructs

The System

The above picture illustrates our idealized system the way we wanted it to be . It consists of two plasmids with FFT and SST respectively. Both plasmids have a toxin-antitoxin system introduced which works as a form of safety to prevent horizontal gene transfer (read more about it further down the page). The two enzymes, FFT and SST, produce together the non-digestible inulin from sucrose. Along with the two plasmids there is also a sigma-E gene that functions as a regulator gene in our kill-switch system.

The sigma-E is an alternative sigma factor that controls the extracytoplasmic stress response in E. coli. The idea is to have an L-Rhamnose sensitive promoter that expresses this essential gene.

The L-Rhamnose would be in the yoghurt with our bacteria and function as a limiting lifetime for the consumed bacteria. L-Rhamnose is a non-digestible sugar which passes through the system and thereby inactivates the sigma-E gene. The consumed bacteria from the yoghurt would inevitably die after a while.

Data For Our Favorite New Parts

Data For Pre-existing Parts

Killswitch

During the construction of a killswitch, we stumbled upon a very concerning fact. A normal killswitch inducible by a promoter can be rendered useless in the case of frameshift mutations (and any other mutation, that affects the gene-product). Therefore we chose to construct killswitches with a less likely chance of being frameshifted out of order.