Investigating a possible role for the bacterial signal molecules N‐acylhomoserine lactones in Balanus improvisus cyprid settlement. Issue 9 (18th March 2013)

• Record Type: Journal Article
• Authors: Tait, Karen; Havenhand, Jon
• Is Part Of: Molecular ecology. Volume 22:Issue 9(2013)
• Page Start: 2588
• Page End: 2602
• Publication Date: 2013-03-18
• Subjects: Molecular ecology -- Periodicals; Molecular population biology -- Periodicals; 576
• DOI: 10.1111/mec.12273
• Languages: English
• ISSNs: 0962-1083

Abstract

<abstract abstract-type="main" id="mec12273-abs-0001"> <title>Abstract</title> <p>Increased settlement on bacterial biofilms has been demonstrated for a number of marine invertebrate larvae, but the nature of the cue(s) responsible is not well understood. We tested the hypothesis that the bay barnacle <italic>Balanus improvisus</italic> utilizes the bacterial signal molecules N‐acylhomoserine lactones (AHLs) as a cue for the selection of sites for permanent attachment. Single species biofilms of the AHL‐producing bacteria <italic>Vibrio anguillarum</italic>, <italic> Aeromonas hydrophila</italic> and <italic>Sulfitobacter</italic> sp. BR1 were attractive to settling cypris larvae of <italic>B. improvisus</italic>. However, when AHL production was inactivated, either by mutation of the AHL synthetic genes or by expression of an AHL‐degrading gene (aiiA), the ability of the bacteria to attract cyprids was abolished. In addition, cyprids actively explored biofilms of <italic>E. coli</italic> expressing the recombinant AHL synthase genes <italic>luxI</italic> from <italic>Vibrio fischeri</italic> (3‐oxo‐C6‐HSL), <italic>rhlI</italic> from <italic>Pseudomonas aeruginosa</italic> (C4‐HSL/C6‐HSL), <italic>vanI</italic> from <italic>V. anguillarum</italic> (3‐oxo‐C10‐HSL) and <italic>sulI</italic> from <italic>Sulfitobacter</italic> sp. BR1 (C4‐HSL, 3‐hydroxy‐C6‐HSL, C8‐HSL and 3‐hydroxy‐C10‐HSL), but not <italic>E. coli</italic> that did not produce AHLs. Finally, synthetic AHLs (C8‐HSL, 3‐oxo‐C10‐HSL and C12‐HSL) at concentrations similar to those found within natural biofilms (5 μ<sc>m</sc>) resulted in increased cyprid settlement. Thus, <italic>B. improvisus</italic> cypris exploration of and settlement on biofilms appears to be mediated by AHL‐signalling bacteria in the laboratory. This adds to our understanding of how quorum sensing inhibition may be used as for biofouling control. Nonetheless, the significance of our results for larvae settling naturally in the field, and the mechanisms that underlay the observed responses to AHLs, is as yet unknown.</p> </abstract>