Team:Stockholm/Modelling/Introduction

As a future work of our project the aim is to manipulate the bacteria to reproduce in environments outside the laboratory for bacterial therapy. Bacteria will express proteins fused to cell-penetrating peptides (CPPs) while growing on skin. Since bacteria will be outside normal lab environment, we need to choose proper assumptions to fit the situation.

In our pEX expression vector we have lacI as a repressor of the P_tac promoter, so the idea is to have a cream on the skin which contains lactose as an inducer for P_tac. As a matter of fact good timing is needed before CPP reaches critical concentrations in bacteria. It seems in this scenario we need to take into account possible details such as degradation rates, cell growth, and factors that will affect stable production such as translational and transcriptional delay. Therefore, we are aiming to achieve a predicting model for production of protein in our system of bacteria and have the model to describe how production is induced in bacteria from the time induction starts until it is dead because of CPPs penetrating bacteria membrane. In this model we will not include or model or try to predict re-pigmentation, because of high complications in target human cells. For further reading about mathematics one can look in this article: [http://www.biomedcentral.com/1752-0509/3/60 The mathematics of tanning J. et al. 2008].

Out of these details, there are some data we need to know in advance. These details include:

• How much lactose is available for bacteria? i. e. Concentration of lactose on the skin
• Production rate for biomolecules in host bacteria
• Allolactose/lactose degradation rate
• Allolactose/lactose absorption through skin
• Critical concentration of CPP