Gut Bacteria Can now Be Engineered

No, we’re not just telling stories – gut bacteria can now be engineered to detect and treat really potent diseases like colon cancer, or immune disorders.

Yesterday, researchers from MIT published a new study in the Cell Systems journal, where they showcased how the Bacteroides thetaiotaomicron bacterium in the human gut can be controlled through the careful encoding of circuits, memory switches, and sensors into it.

By using this complicated process of biological engineering, the most common bacteria in our intestines will be able to remember, feel, and act to certain signals happening around it which would be used as triggers. This may prove revolutionary in the way of preventing, diagnosing, as well as treating colon cancer, or bowel diseases.

Timothy Lu, co-leader of the study, mentioned that such research previously only existed for rather uncommon forms of gut bacteria, like the E.coli. For this project, Lu, who is a biological engineering associate prof., as well as of computer science, and electrical engineering at the popular Massachusetts institute, worked with colleague Christopher Voigt, also a professor of bio engineering at MIT.

The motivation behind choosing strains of bacteria like Bacteroides thetaiotaomicron was that these are abundantly present in most humans, and provide stability when colonizing the gut for longer periods of time.

Examples of triggers that could turn these gut bacteria on or off, Voigt said, would be the different food additives that appear in foods that we eat the most, let’s say sugars.

But how did they add memory to bacteria?

The scientists used recombinases, an interesting class of proteins, which are able to record into the DNA of the bacteria information gathered from recognizing specific, preprogrammed DNA strands. When a protein sees a DNA address it is programmed to record, it inverts its direction so the information remains with the host bacteria.

Another function added by the scientists was CRISPR interference, a type of technology that can control different genes of the bacteria so as to be able to command it to eat up a specific nutrient, or to defend itself against antimicrobial molecules.

The scientists tested these biologically engineered bacteria on mice with promising results – the strains remembered exactly what the mice had eaten. The next step, they point out, is to try this on other types of bacteria, so that the method would be applicable to more and more people.

Image source: sciencemag.orgcialis directions