Certain bacteria naturally present in our human intestines have developed a mechanism to become resistant to antibiotics. When these bacteria are faced with the antibiotic, as in when we eat antibiotics, they transfer a special piece of DNA called the transposon to those bacteria that don’t yet have resistance. In this way, more bacteria in our intestines become resistant to the antibiotic, and the striking aspect is that the more antibiotic we eat, more and more bacteria are becoming resistant.
My PhD thesis looked at one such transposon DNA called NBU1, and how its own proteins called Integrase proteins help it to move from one bacteria to another. In the new bacteria, the Integrase proteins cut both the transposon DNA as well as the bacteria’s own DNA, and integrate the transposon into the bacterial chromosome.
Explanation of the video:
In scene 1, inside the human intestine, there are some resistant bacteria (with the blue sashes), and some weak ones (without blue sashes). When the bacteria are faced with the antibiotics (pink), the strong ones successfully fight them, while the weak ones barely survive. But because of the antibiotics, the strong bacteria can make a copy of the transposon (the blue sashes split into two), and transfer one copy to the weak bacteria ( the handing over one blue sash ). Now all the bacteria are resistant, and this is shown by all of them successfully fighting the antibiotics on a second exposure.
In scene 2, we are going inside a bacterial cell, to show what happened to the transposon DNA (blue) when it entered the weak bacteria. The transposon DNA (blue) and the bacterial chromosome (white) are on their own inside the bacterial cell, until the Integrase proteins (Green) are made. Four Integrase proteins bring the transposon DNA and the bacterial DNA close together. The proteins cut the DNA in pairs, and exchange the DNA strands (shown by exchange of hands), and now the transposon DNA is part of the bacterial chromosome.