Extending our bacterial photography system across engineering disciplines

 

Jessica Sandoval

For Module 2, we combined the beauty of a biological system with programming. We created our own bacterial photography system and later tuned the image quality by modifying the phosphorylation events of a photoreceptor kinase, much like tuning the knobs of an instrument. We were able to not only create a new system by combining two well-studied pathways in cyanobacteria and E.coli, but create photographs from plated engineered E.coli.  

Module 2 was my first exposure to synthetic biology, but the thought process was analogous to macroscopic engineering principles. We first generalized the engineered system to two black boxes, a signal sensing box and an output generation box. The signal sensing box functioned to detect photons from a red light source.  The output generation box took in the signals from the light sensing box and outputted a black precipitate. Unpacking the black boxes, the first box contained a modified photoreceptor with kinase activity. The second box involved the transcription/translation of a B-galactosidase enzyme. We were able to next “reach into” these black boxes and fine tune the phosphorylation events that regulated their outputs. By generalizing the engineered system to black boxes, we created a fundamental signals and systems problem. This thought process used to approach our system can be extended across all engineering disciplines, not just to synthetic biology.  

In fact, we applied the logic flow of the engineered bacterial photography system to electronics. Within this example, we created a simple system of electrical components that would simply amplify an input signal and turn on an LED. However, instead of playing around with E.coli, we tinkered with much more robust components: resistors, OpAmps, switches, and LEDs. This electrical engineering approach allowed us to modify our system and generate an output immediately, as opposed to waiting for incubations. It was a really exciting demonstration of the applicability of our biological system for other engineering disciplines. For me, this was one of the most important lessons from Module 2. The fact that the mechanisms underlying any engineered system, whether it be as small as a programmed cell to as large as space flight systems, all serve similar roles. Regardless of scale. Regardless of media. And that is truly fascinating to me.