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Team:KULeuven/Death
From 2011.igem.org
Modeling Celldeath
1. Description of the cell death system
For a full description, we refer to the extended project page. This section shows only a brief summary of the cell death description.
The cell death mechanism we use, will be induced when stimulus 1 (L-arabinose) or stimulus 2 (lactose) and at the same time a cold temperature is applied.
Procedure: We grow the bacteria at the optimal temperature of 37 degrees. Then we produce the protein we wish by applying the correct stimulus, e.g., L-arabinose to produce AFP. After synthesizing the desired amount of protein, we lower the temperature to induce the cell death mechanism.
CELL DEATH SCHEME
BIOBRICKS CELL DEATH
The promoters for production of the ribolock Colicin E2 operon (Bba_K131009) are two hybrid promoters: pLac-LuxR promoter and pLux-CI promoter. We describe the promoter kinetics in this subsystem with simplified mass equations. This is a simplification because hill kinetics will approach better the transcription in vivo than mass equations. In the full model, hill kinetics is applied.
FIGURE 1: pLac-luxR hybrid promotor
FIGURE 2: plux-cI promotor
CelldeathODE.pdf
PARAMETER TABLE
2. CellDeath Model
CELL DEATH MODEL3. Simulations
We made a simulation in such a way that the ribokey-RNA is present at a constant value (figure 3). With this assumption, the only variable in the production for CeaB would be CeaB mRNA which linearly increases. Initially the production of CeaB is increasing non-linearly, but after a certain amount of time CeaB production becomes linear (figure 4); at that moment the degradation of CeaB is becoming important as well. Production of CeaB is the rate-limiting reaction.
Here, the input of lactose or arabinose is assumed to be constant. To improve this model, it could be updated with a varying input for lactose or arabinose. Also a temperature-varying parameter will be necessary, because the promoter we use is temperature sensitive.
FIGURE 3: ribokey-RNA value hold constant, increase of CeaB
FIGURE 4: Eventually CeaB concentration increases linearly with time
