One of my favorite protocols has always been the transformation of bacteria. Introducing new DNA to bacteria is an essential laboratory technique and has applications in almost every field. Transforming bacteria helps us test a myriad of scientific theories, and it's a surprisingly easy technique to use. You simply add the bits of DNA you want taken up into a vial with the bacteria and warm them slightly in a water bath. After this, you put the bacteria onto a plate containing antibiotics, and the results are visible the very next day. Bacteria that would normally be killed by the antibiotics instead grow and thrive so that we can get lots of copies of the DNA we added to them, providing us with raw material that we can then sequence.
An ampicillin plate with a common, nonpathogenic strain of E. coli transformed to be resistant to antibiotics growing on it. The inserted plasmid will be isolated and sequenced after culturing more bacteria
Transformation is a fundamentally fascinating procedure. When transforming bacteria, you are inserting DNA that is completely foreign to the bacteria and using its own cellular machinery to replicate that DNA. This can be induced by chemicals, heat, UV or electric shock. Once inserted, not only is the DNA replicated but the bacteria will begin producing the proteins that the DNA encodes for. These proteins can then be used for experimentation, or they may be used for industrial or medical purposes. For example, human insulin is now produced by bacteria instead of being extracted from thousands of pounds of pig pancreases. To me, it often seems like something out of a sci-fi novel. A simple water bath has made a huge leap in the way we produce some helpful chemicals.
I also enjoy transformation because of how visually clear it is. Unlike much of the work I do, you get nearly instant feedback on the success or failure of your procedure. You simply look for the presence of bacterial colonies, and if they are there you know that your experiment was successful. From there you can move on toward protein induction to produce what the DNA encodes for or sequencing to read the code of the DNA.
Transformation is an incredibly important technique and enables us to produce thousands of different proteins that are vital for scientific research, as well as many other uses. Everything from glowing proteins to lifesaving insulin can be produced by tiny bacteria growing in a flask.
Michael Passalacqua is a 2016 Lloyd Noble Scholar in Plant Science from New York, New York. He is a rising senior at Rice University and is majoring in biological sciences with a focus on genetics. His summer research project is studying the pathway of a gene that, when inactivated, vastly increases the biomass of crops harvested multiple times.