The effect of quorum-sensing blockers on the formation of marine microbial communities and larval attachment

Abstract

We studied the effect of the quorum-sensing (QS) blockers 5-hydroxy-3[(1R)-1-hydroxypropyl]-4-methylfuran-2(5H)-one (FUR1), (5R)-3,4-dihydroxy-5-[(1S)-1,2-dihydroxyethyl]furan-2(5H)-one (FUR2) and triclosan (TRI) on the formation of bacterial biofilms, and the effect of these biofilms on the larval attachment of the polychaete Hydroides elegans and the bryozoan Bugula neritina. 14-day-old subtidal biofilms were harvested from artificial substrata and were allowed to develop in the laboratory with and without QS blockers. QS blockers inhibited the production of violacein by the QS reporter strain Chromobacterium violaceum CV026 and did not affect the metabolic activity of bacteria in multispecies biofilms. At a concentration of 10(-3) M all three tested compounds inhibited the establishment of microbial communities, but at one of 10(-4) M only FUR2 inhibited establishment. The tested QS blockers caused changes in bacterial density and bacterial community structure, as revealed by terminal restriction fragment length polymorphism and FISH. The groups most affected by QS blockers were Alphaproteobacteria, Gammaproteobacteria and the Cytophagales. Larvae of H. elegans and B. neritina avoided settling on biofilms that had developed in the presence of QS blockers. Our results suggest that QS blockers directly control the formation of multi-species biofilms, and indirectly - by means of biofilm properties - affect larval attachment on these modified biofilms.

Anthropogenic pollutants affect ecosystem services of freshwater sediments: the need for a “triad plus x” approach

“…Anthropogenic pollutants can indirectly impact the EPS secretion pattern by affecting bacterial physiology or by inducing shifts in bacterial species composition. For the antibacterial compound triclosan, it was shown that the pollutant interfered with the quorum sensing signalling of Gram-negative bacteria (direct effect on EPS compounds that are strongly involved in cell communication); as a result, bacterial attachment, growth and the formation of biofilm were significantly hampered (Dobretsov et al 2007). Thus, altering EPS secretion might significantly impair important functionalities of biofilm for the aquatic habitat such as sediment stabilisation (also see Section 2.3).…”

The RNA Processing Enzyme Polynucleotide Phosphorylase Negatively Controls Biofi lm Formation by Repressing Poly-N-Acetylglucosamine (PNAG) Production in Escherichia coli C

“…TCS inhibits fatty acid synthesis with subsequent perturbation of the bacterial membrane [13] but it also interferes with the quorum-sensing signaling of Gram-negative bacteria; thus inhibiting their attachment, growth and formation of biofilm [46]. In that context, Dobretsov et al [46] reported on the specific sensitivity of Alpha-and Gammaproteobacteria as well as on Cytophagia of the phylum Bacteroidetes to concentrations of TCS of 10 -3 M in contrast to the unaffected Gram-positive phylum of Firmicutes. While in the present experiment Bacteroidetes members were indeed sensitive to TCS, species belonging to the Alphaproteobacteria (Brucellacea/Pseudochrobactrum glaciei) as well as Firmicutes (Carnobacteriaceae/Carnobacterium mobile, C. inhibens) were found solely from samples exposed to high TCS concentrations (T5, 100 mg L -1 ).…”

Evidence for the dynamics of Acyl homoserine lactone and AHL-producing bacteria during subtidal biofilm formation

“…It was proposed that bacteria might use QS as a weapon to compete for survival or to dominate in a natural niche (Waters and Bassler, 2005;Defoirdt et al, 2008). Indeed, in the laboratory, AHL was shown to mediate the interaction between Pseudomonas aeruginosa and Agrobacterium tumefaciens in biofilm cocultures , whereas AHL-QS blockers and the presence of AHLs were found to change bacterial community composition and function in natural environments and activated sludge (Valle et al, 2004;McLean et al, 2005;Dobretsov et al, 2007).…”