title: Dynamics of AHL mediated quorum sensing under flow and non-flow conditions.
abstract: Quorum sensing (QS) describes the capability of microbes to communicate with each other by the aid of small molecules. Here we investigate the dynamics of QS-regulated gene expression induced by acylhomoserine lactones (AHLs) in Pseudomonas putida IsoF containing a green fluorescent protein-based AHL reporter. The fluorescence time course of individual colonies is monitored following the external addition of a defined AHL concentration to cells which had previously reached the QS-inactive state in AHL-free medium. Using a microfluidic setup the experiment is performed both under flow and non-flow conditions. We find that without supplying external AHL gene expression is induced without flow while flow suppresses the induction. Both without and with flow, at a low AHL concentration the fluorescence onset is significantly delayed while fluorescence starts to increase directly upon the addition of AHL at a high concentration. The differences between no flow and flow can be accounted for using a two-compartment model. This indicates AHL accumulation in a volume which is not affected by the flow. The experiments furthermore show significant cell-to-cell and colony-to-colony variability which is discussed in the context of a compartmentalized QS mechanism.
authors.affiliation: Ludwig-Maximilians-Universität München, Munich, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Meyer
authors.forename: Judith A
authors.initials: JA
authors.lastname: Megerle
authors.forename: Christina
authors.initials: C
authors.lastname: Kuttler
authors.forename: Johannes
authors.initials: J
authors.lastname: Müller
authors.forename: Claudio
authors.initials: C
authors.lastname: Aguilar
authors.forename: Leo
authors.initials: L
authors.lastname: Eberl
authors.forename: Burkhard A
authors.initials: BA
authors.lastname: Hense
authors.forename: Joachim O
authors.initials: JO
authors.lastname: Rädler
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D015964:Gene Expression Regulation, Bacterial; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008025:Ligases / Q000378:metabolism; D008954:Models, Biological; D016958:Pseudomonas putida / Q000378:metabolism*; D053038:Quorum Sensing; D015533:Transcriptional Activation
chemical_list: D054742:Acyl-Butyrolactones; D049452:Green Fluorescent Proteins; D008025:Ligases; C449816:N-acylhomoserine lactone synthase