IGEM:IMPERIAL/2006/project/Oscillator/project browser/Predator Construct/Modelling
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| Super Parts | Molecular Prey-Predator Oscillator | |
|---|---|---|
| Actual Part | ||
| Sub Parts | Test Sensing Predator Construct | Test Killing Predator Construct | 
Model assumptions and relevance
- General assumptions on gene expression modelling:
- Quasi-steady state hypothesis on mRNA expression.
 - Gene activation can be approximated by Hill equations.
 
 
- Assumptions linked to the quorum sensing:
- As a first approximation, we assume that luxR and AHL molecules form a heterodimer (even if it has been found that the complex formed is more complicated).
 - The degradation rate of luxR and aiiA is mainly due to the growth dilution.
 
 
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Model description of the growth of the predator
- mathematical description of the predator growth and death:
- [math]\displaystyle{ \frac{d[luxR]}{dt} = \frac{c * [AHL] * [luxR]}{(c0 + [AHL] * [luxR])} - gd * [luxR] }[/math]
 - [math]\displaystyle{ \frac{d[aiiA]}{dt} = \frac{c * [AHL] * [luxR]}{(c0 + [AHL] * [luxR])} - gd * [aiiA] }[/math]
 
 
- insert a graphical representation if possible (e.g. CellDesigner display)
 - link to SBML file or matlab.
 
Model variables and parameters for the growth of the predator
(list all the variables and parameters of the model in a table, specifying if their values are known, unknown, to be measured.)
| Variables | ||||
| Name | Description | Initial Value | Confidence | Reference | 
|---|---|---|---|---|
| AHL | homoserine lactone acting as the prey-molecule | 0 | depends how good is the control of the prey positive feedback | links | 
| luxR | molecule acting as the sensing module for the predator | 0 | to be measured as we might have to deal with some leakage of the promoter | links | 
| aiiA | molecule acting as the killing module of the prey for the predator | 0 | to be measured as we might have to deal with some leakage of the promoter | links | 
| Parameters | ||||
| Name | Description | Value | Confidence | Reference | 
|---|---|---|---|---|
| c | maximum synthesis rate of the pLux promoter | to be characterized | to be measured | links | 
| c0 | dissociation constant according to Hill eq | to be characterized | to be measured | links | 
| gd | growth dilution | to be characterized | to be measured | links | 
Model description of the killing of the prey molecule by the predator
- mathematical description of the killing of the prey:
- [math]\displaystyle{ \frac{d[AHL]}{dt} = \frac{b * [aiiA] * [AHL]}{(b0 + [AHL])} - e * [AHL] }[/math]
 
 
Model variables and parameters for the killing of the prey molecule by the predator
| Variables | ||||
| Name | Description | Initial Value | Confidence | Reference | 
|---|---|---|---|---|
| AHL | homoserine lactone acting as the prey-molecule | 0 | depends how good is the control of the prey positive feedback | links | 
| aiiA | molecule acting as the killing module of the prey for the predator | 0 | to be measured as we might have to deal with some leakage of the promoter | links | 
| Parameters | ||||
| Name | Description | Value | Confidence | Reference | 
|---|---|---|---|---|
| b | Maximum degradation rate catalyzed by aiiA | ... | to be measured | links | 
| b0 | Michaelis-Menten constant of enzyme reaction | ... | to be measured | links | 
| e | AHL wash-out | variable | to be measured/can be varied by chemostat | links | 
Dynamical and sensitivity analysis
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- Template__HIDER__
 
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- analyze model in order to show how the part could fulfill its specifications
 - insert graph and charts
 
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- We have decoupled the predator into sensing and killing parts
 - For detail modelling, please refer to the modelling section in subparts.
 
Characterization
- To characterize the part, we have to measure the production rate and aiiA enzyme activity seperately
 - For details characterization, please refer to subparts