Project 7: Inter-Kingdom cross talk via quorum sensing compounds in bacteria-diatom biofilms

Frederike Stock has been appointed researcher for project 7. Based at the University of Ghent, her aim is to examine the nature and biological functions of inter-kingdom cross talk via quorum sensing compounds produced by bacteria and diatoms, and to test the use of these compounds as anti-fouling agents in photo-bioreactors. It has been shown recently that some diatoms are capable of suppressing quorum sensing activity in bacteria.

Conversely, genome data suggest that diatoms may be capable of responding to bacterial quorum sensing (QS) molecules. Using a collection of available strains derived from inter-tidal biofilm communities, the production of specific QS molecules and their effect on diatoms are screened using biological assays and chromatography – mass spectrometry (MS) techniques for direct identification of signaling molecules. Quorum quenching by metabolites released by diatoms or in vivo degradation of QS-molecules by diatoms is evaluated using different reporter strains.

project-7

Active compounds or degradation products of QS molecules are isolated via bioassay-guided fractionation using different extraction techniques and preparative chromatography. Identification is done via NMR and MS, and by comparison with authentic QS compounds and synthetically prepared products. Based on these results, our library of modified QS compounds will be extended and used in activity testing on biofilm diatoms in bio-assay experiments. Targeted transcriptomics (carried out at UGent) and exo-metabolomics (via a secondment at the University of Jena) studies are being combined to examine the metabolic pathways involved in the response of diatoms to QS compounds. This will become the basis for functional studies on quorum sensing interference in bacterial reporter lines (which will be done via a secondment at the University of Konstanz). Economically-viable compounds able to reduce biofilm formation in laboratory conditions are being incorporated in a selection of plastics and their capacity to act as anti-fouling coating is being tested (via a secondment at PROVIRON in Belgium).

Founded in 1817 by King William of Orange, the University of Ghent (UGent) is one of the top universities in Belgium and has over 40,000 students. The Department of Plant Systems Biology was established in the mid-1990s in collaboration with Flanders Interuniversitary Institute for Biotechnology (VIB). The Department grew from a focus on plant genetics to the study of basic biological processes in plants based on the ethos that plants constitute an ‘interesting and important biological system that contrasts animal life’.

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