The Isolation and Identification of an Unknown Quorum Sensing Signal Molecule

Abstract

Quorum sensing is the biological process by which single-celled organisms produce and use small molecules to communicate population density and concentration amongst each other. Though previously discovered and identified molecules were shown to be specific to the species of bacteria from which they were isolated and active only within the prokaryotic kingdom, new evidence shows that there is an unknown molecule produced by yeast that can activate the quorum sensing pathways of V. harveyi, a bacteria species that uses quorum sensing to fluoresce. The identification of the unknown molecule which influences bacterial behavior would be highly significant to understanding inter-kingdom quorum sensing. This example of inter-kingdom communication, which suggests that eukaryotic cells can manipulate bacterial behavior, may lead to new approaches for control of infectious disease. Our lab group strives to develop chromatographic methods to isolate unknown molecules from complex solutions, with the goal of optimizing conditions for isolation that are practical, scalable, and produce highly purified product. Once concentrated to a sufficient amount for characterization, the goal was to identify the molecule of interest through the use of analytical methods, most heavily focused on 13C NMR, 1H NMR, and mass spectroscopy. The results of our efforts culminated in the identification of the molecule, now known to be norfuraneol. Due to our research and identification, a number of questions have been raised about how this molecule activates its respective phenotypes and concentration-based gene expression in both yeast and V. harveyi. The knowledge of this molecule, its structure, the problems related to concentrating it, and its activation of different pathways in two distinct kingdoms has sparked further research into interkingdom quorum sensing and how it can be controlled.