The continuous story of bacteriocins until emerging origins and methods for discovery
Sylvie Rebuffat
Muséum national d’Histoire naturelle - MNHN, Unité Molécules de Communication et Adaptation des Microorganismes - MCAM, UMR 7245 CNRS-MNHN, CP 54, 57 rue Cuvier, 75005 Paris email: sylvie.rebuffat@mnhn.fr
Discovery of the first bacteriocin dates back to 1925, when the belgian microbiologist André Gratia was studying the antagonism between strains of Escherichia coli. Since then, lots of bacteriocins have been identified, essentially in Gram-positive bacteria (mainly lactic acid bacteria) and in a lesser extent in Gram-negative ones (especially Enterobacteriaceae), which were named microcins. Since the 2000s, the discovery of novel families of bacteriocins/microcins became more and more efficient and rapid, thanks to the increasing number of available bacterial genomes and the use of performing genome mining tools.
It is now established that if many bacteriocins are conventional unmodified peptides, more and more belong to the fast-growing family of the ribosomally synthesized and posttranslationally modified peptides (RiPPs). In-depth studies have permitted deciphering the biosynthetic pathways and associated enzymatic machineries, and the mechanisms of action, including export out of the producers, uptake into susceptible bacteria, and binding to one or several targets at the membrane or cytoplasm level.
Such leaps allowed revealing over recent years that microbiota, and especially the gut microbiota, are rich sources of bacteriocins and microcins. Inside such complex microbial communities, bacteria develop social behaviours, mainly of cooperation and competition, which are mediated by communication or harmful molecules. As such, bacteriocins/microcins produced particularly by Firmicutes and Enterobacteriaceae, appear as potent weapons able to modulate microbiota, kill their competitors, and even displace a pathogen from the niche.
Currently, the fast and relentless development of artificial intelligence triggers an accelerated rate of discovery of novel bacteriocins/microcins. This is accompanied with the identification of novel biosynthetic pathways and enzymes, and mechanisms of killing and competition. This context will facilitate and amplify performing deeper studies on the ecological roles played by bacteriocins and microcins within microbiota, thus permitting to better evaluate and develop their therapeutic potential.
