Bacteria can be both useful and lethal. In either case, scientists want total control over them to maximise their efficiency or prevent any diseases. However, it does sounds impossible: how can humans control a bacterium, which is a free living organism so small we can’t see it with our naked eye and is incapable of understanding our commands? But of course they have accomplished this, or otherwise I wouldn’t be writing an article on it.
Subjugating bacteria is done by a simple method. All living organisms require proteins made out of amino acids to live, and bacteria are no different. They use them to carry out many varied functions: they act as enzymes, hormones, connective tissue… so if you control how bacteria make proteins, you can basically dictate how they live their lives. Since proteins are coded by the DNA, scientists tweaked the genetic information so that bacteria didn’t code for proteins they way they would usually do. But changing the whole genome is a long, tiresome process; so instead, they targeted a specific set of genes which code for a specific set of proteins: those that are crucial for a bacterium to make other proteins. It is quite effective. If bacteria can’t make the proteins that guide DNA transcription and translation (the processes that produce proteins), then the bacteria are hindered and can’t work any further.
The modifications involved changing the bases in the DNA sequence so they didn’t code for the usual, natural amino acids. Instead, some new bases introduced coded for an artificial amino acid, created and only found in the lab, so proteins could only be made if this one artificial amino acid was present. This idea, although creative, was developed by two independent teams, one of which used a large, artificial amino acid and the other used three different artificial amino acids. Either way, if these bacteria wanted to survive, they would have to stay in the lab, the only place where they can obtain the amino acid necessary for creating proteins.
The main implications of this development are related to genetically modified organisms (GMOs). People fear that creating beings with features enhanced in the laboratory is dangerous, and if they somehow make it into the wild and grow there, they can harm other, more natural species, or reproduce with them, which would destroy the natural balance of natural selection. This technique solves both of those problems, since the new GMOs developed with dependency on this amino acid would only be able to live in the lab, and could be easily controlled and kept in small numbers.