Summary
It is long known that in multicellular organisms, short peptidic or proteinaceous compounds are able to regulate important physiological processes via intercellular signaling. Currently there are several lines of evidence that unicellular organisms also possess various specialized auto-regulatory systems, in which secreted compounds play central roles. Via this intercellular signaling micro-organisms are able to ‘communicate’ with each other and react to continuously changing environmental conditions with a collective response. Examples of intercellular signaling compounds include quorum-sensing molecules, chemo-attractants and antimicrobial compounds. In addition to the non-ribosomal antibiotic peptides as studied in NPC Project 3.2, several of these signaling compounds are actually directly encoded in the genome, for example mating pheromones and quorum sensing molecules of gram-positive bacteria. This project aims at focussing on this class of naturally occurring unicellular signaling peptides. For this we will develop and apply a quantitative peptidomic approach to screen the culture media of various industrially relevant micro-organisms. Micro-organisms have proven themselves to be an excellent source of novel natural compounds, such as peptide antibiotics. In addition, a deeper insight into their auto-regulatory processes will ultimately allow higher levels of quality control of microbial cultures, for example in bio-technology/industry related applications.