Team:Minnesota/Model
Minnesota
Our model of the delayed auxotrophy system, which acted via thymineless death, first defined a mean number of plasmids in each bacterium and distributed plasmids across the initial population of bacteria according to a standard deviation from this mean value. With each division, a time step that was defined to be one day, some plasmids were lost, with a probability defined in the model. When a bacterium had zero remaining plasmids, it was considered “dead” and removed from the count of total bacteria. Because we did not have time to experimentally determine initial plasmid number and rate of plasmid loss, sensitivity analysis was performed for these values within ranges determined from literature values. The rate of plasmid loss was varied between 0.001% and 50% loss per division, giving the first plot seen above. As the rate of plasmid loss increased, the peak number of bacteria decreased and rate at which the bacterial population decreased rose, as shown by the steeper downward slope after the peak with higher rates of plasmid loss. The initial plasmid number was varied between 40 and 80 plasmids per bacterium, with a standard deviation of 10, giving the second plot shown above. As the initial plasmid number increased, the peak number of bacteria increased and the rate of decrease in the bacterial population decreased.
