The human body and its microbiota harbour a large amount of phages. These infect bacteria as virus particles to ensure their own survival. One of their strategies is to integrate into the bacterial genome and multiply via bacterial cell division. However, external signal molecules can trigger the phages sudden awakening from their dormant stage. Once activated, they destroy their host, the bacterium, and thus release their newly produced viral particles. With a prestigious ERC Consolidator Grant of the European Research Council, Thomas Böttcher investigates the switch from the sleeping (lysogenic) to the activated (lytic) lifestyle of phages.
“We wanted to investigate whether, in the complex microbial ecosystems, there are also microbes that specifically activate phages in order to use them against their competitors,“ says Thomas Böttcher, Professor of Microbial Biochemistry at the Centre for Microbiology and Environmental Systems Science (CMESS) and at the Faculty of Chemistry. Indeed, the researchers could show that the bacterium Pseudomonas aeruginosa produces large amounts of a signal molecule that triggers the conversion of a phage, residing in a strain of the species Staphylococcus aureus, from a quiet companion into a deadly parasite. The current study demonstrates the efficiency of activation of latent phages by chemical signaling agents in the battle for space and resources between bacterial strains. It provides the first evidence that chemical signaling agents can exhibit selectivity for specific phages in a polylysogenic bacterial strain.
