Quorum sensing in Streptomyces coelicolor: Regulation of the SCB signalling system that controls the synthesis of antibiotics

Soil bacteria of the genus Streptomyces are of great biotechnological interest since they are one of the main sources of the natural antibiotics used nowadays in medicine. These bacteria communicate with other members in their population to coordinate the synthesis of antibiotics to make it more efficient. For this purpose they use small chemical signalling molecules. In Streptomyces coelicolor, the target of our study, and producer of several antibiotics, these molecules are called SCBs (Streptomyces coelicolor Butyrolactone). Previous research on the SCB signalling system in this bacterium showed its relevance in the control of antibiotic production and the large complexity of this system that is yet not fully understood. In this PhD thesis the roles of the proteins involved in this communication system in S. coelicolor have been extensively studied. We have identified and characterised additional essential proteins involved in the synthesis of the SCB signalling molecules and described new regulatory factors that govern the functioning of this system. The information presented here contributes to a better understanding of such a complex regulatory mechanism and of the regulation of antibiotic production in these bacteria. This is of great relevance for the design of new strategies to increase the production of antibiotics by manipulating antibiotic biosynthetic pathways and provides important tools for the discovery of new natural compounds with antimicrobial activities.