Benedict Arnold has nothing on your average bacteria. Battles between the one-celled organisms rage on all day and all night between different species and individuals. So why did a paper from Nature Publishing Group generate articles calling bacteria “Benedict Arnold”? (The articles in question can be found here.) Before answering that question, I should start by saying what the paper shows is really cool, and it’s a great example of how synthetic biology could be used to really help people. A lab from Singapore made an E. coli strain that recognizes a disease-causing bacteria, P. aeruginosa. When P. aeruginosa tries to plan out with others of their kind their next move using small molecules, the synthetic strain of E. coli sees those molecules and starts making a crud load of P. aeruginosa poison and then explodes, releasing a shower of P. aeruginosa killing goop. It’s a cool way to have bacteria that already live in your gut (E. coli) try to kill off something that could make you sick. The lab hasn’t used it in people yet, but their results are still really promising. Back to the Benedict Arnolds. Benedict Arnold? There are tons of different species of bacteria that live in your gut; your body actually has more bacterial cells than human cells within it. Most of the time, your cells and all the bacteria get along, but a bacteria that kills other bacteria is not really novel. And from E. coli’s point of view (if I can speak for our little friends), they’re killing another species, not one of their own. Bacteria killing bacteria is no more traitorous than someone setting a mousetrap (although there are ways to be more humane). Bacteria constantly are competing for resources, and all is fair in love and war. One species killing another off is nothing new. Just ask the Dodo. What makes this paper cool is the fact that scientists have designed bacteria that don’t care about their own interests, but instead will kill upon command. Not only that, they’ll explode, going against their own well-being. This article has a better analogy than Benedict Arnold, calling them suicide bombers. Suicidal E. coli on a mission to fight disease. How cool is that? To illustrate how cool, I made the illustration below. Please do not tell my boss I wasted time on this.