Team:Davidson-Missouri Western/Time-Delayed Growth

Many iGEM projects over the years have wanted cells to communicate to each other and the receiver cells to respond only after they have gotten the message from the sender. The problem has been that all the cells grow at the same time. What was needed was a way to make the sender cells grow first and the receiver cells grow later.

Our hash function also required time-delayed growth on agar plates. To accomplish this, we seed the plate with cells at the same time. One colony is ampicillin resistant (top right corner of photos and movie) and all the others lack amp resistance. As the initiating colony grows, it destroys the antibiotic in an ever widening circle of the media. This permits the amp-sensitive cells to begin to grow. The line going down was continuous cells, while the diagonal and the horizontal tracks were individual colonies/dots of cells.

We have successfully tested our concept on plates. You can see the starting place, a middle figure, and a final image, as well as the time-lapse movie version. The cells grew for 66 hours and photos were taken every 15 minutes.