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From 2012.igem.org

Three Population AND Gate Results

We first checked whether each of the individual population of bacteria fluorosces. It seemed that both population 1 and population 2 worked fine. However, it seemed that there is slight leakage in population 3 as it is not supposed to fluorosce by itself.

<img src='https://static.igem.org/mediawiki/2012/0/00/And_gate_pic_1.png' width="750">

Next, we tried combinations of different populations to make sure that population 3 works as it is supposed to. We tried the combination of population 1 and 3, population 2 and 3 and population 1,2, and 3.

From this experiment, we came to the conclusion that our repressor TetR isn’t completely repressing plas.TetO in population 3, and hence we can see some CFP in the combination of population 2 & 3. However, CFP in population 1, 2 and 3 is brighter and defined , meaning that our system is working better when both population are present together. We tested these populations again by combining them in the same ratio. (100x)

<img src='https://static.igem.org/mediawiki/2012/9/91/AND_gate_pic_2.png' width="750">

From the above experiment, we concluded that our AND Gate works except for some minor leakage when combined with cell population 2 (RFP).

We performed a final experiment to ensure the accuracy of our experiments by centrifuging both populations 1 and 2. Then we transferred the supernantant with quorum sensing molecules to the Population 3 test tube . While at the same time, we added the same amount of broth to the population 3 negative. And the following are the results: 40x

<img src='https://static.igem.org/mediawiki/2012/f/f3/AND_gate_pic_4.png' width="750">

Conclusion: From the above experiments, we can conclude that AND gate seems to work as expected except for some minor leakage of CFP possibly due to weak repression of plas.TetO by Tet R.