The influence of quorum sensing inhibitors against marine functional bacterial biofilm formation

Abstract:

[Objective] To study the influence of natural quorum sensing inhibitors (QSI) against marine functional bacterial biofilm formation. [Methods] Some marine bacterial strains, which could induce the larval settlement of fouling organism, were regarded as target bacteria. Through adding natural quorum sensing inhibitors into the target bacterial cultures during their biofilm formation process, the influence of QSI on the biofilm and planktonic bacteria quantity, biofilm morphology as well as the surface extracellular polysaccharide were studied. [Results] Furanone and pyridine significantly inhibited the biofilm formation of all target bacterial strains at the concentration of 50 mg/L, with the inhibition rate of about 80%. However, indole, penicillanic acid and coumarin exhibited good inhibitory activity only at higher concentrations of 800 mg/L. The results of growth inhibition experiment showed that the inhibitory activity of QSI molecules on target bacterial biofilm formation was much higher than them against planktonic bacteria growth at the same concentration, which indicated that the biofilm formation inhibitory effect of QSI molecules was mainly due to their interference on the quorum sensing system of target bacteria. [Conclusion] This study confirmed that QSI molecules may play an important regulatory role in marine bacterial biofilm formation process. The biofilm induced larval settlement of fouling organisms might be indirectly inhibited through the addition of QSI, which may lead to new anti-fouling substances from another point of view.