Abstract
Marine cyanobacteria are known to produce structurally diverse bioactive specialized metabolites during bloom occurrence. These ecologically active allelochemicals confer chemical defense for the microalgae from competing microbes and herbivores. From a collection of a marine cyanobacterium, cf. Lyngbya sp., a small quantity of a new cyclopropane-containing molecule, benderadiene (2), and lyngbyoic acid (1) were purified and characterized using spectroscopic methods. Using live reporter quorum-sensing (QS) inhibitory assays, based on P. aeruginosa PAO1 lasB-gfp and rhlA-gfp strains, both compounds were found to inhibit QS-regulated gene expression in a dose-dependent manner. In addition to lyngbyoic acid being more active in the PAO1 lasB-gfp biosensor strain (IC50 of 20.4 µM), it displayed anti-biofilm activity when incubated with wild-type P. aeruginosa. The discovery of lyngbyoic acid in relatively high amounts provided insights into its ecological significance as a defensive allelochemical in targeting competing microbes through interference with their QS systems and starting material to produce other related analogs. Similar strategies could be adopted by other marine cyanobacterial strains where the high production of other lipid acids has been reported. Preliminary evidence is provided from the virtual molecular docking of these cyanobacterial free acids at the ligand-binding site of the P. aeruginosa LasR transcriptional protein.
Original language | English |
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Article number | 3965 |
Number of pages | 18 |
Journal | Molecules |
Volume | 28 |
Issue number | 9 |
Early online date | 8 May 2023 |
DOIs | |
Publication status | Published - May 2023 |
Bibliographical note
Funding Information:The facilities and equipment support were provided by the National Institute of Education, NTU and Singapore Centre for Environmental Life Sciences Engineering, NTU. This research is funded by NIE AcRF grant RI 2/20/TLT.
Keywords
- anti-biofilm
- cyclopropane-containing metabolites
- lyngbyoic acid
- marine cyanobacterium
- Pseudomonas aeruginosa
- quorum-sensing inhibitor