ANTI- QUORUM SENSING AND ANTI- BIOFILM COMPOUNDS FROM MARINE MICROBIOME

Quorum Sensing (QS) is a cell to cell communication process relying on the production of signaling molecules that enable the synchronization of gene expression. This process affects different microbial community functions including the ability to develop biofilms. Understanding these communication processes can help develop novel methodologies for producing antimicrobials agents. To date, less than 1% of microbes can be isolated using traditional culturing techniques. Despite this, the emergence of culture-independent and metagenomic techniques, has allowed access to information regarding biochemical pathways characterizing these uncultured microorganisms. In order to assess the quorum sensing inhibition (QSI) characteristics of some uncultured bacterial species, 2500 environmental Bacterial Artificial Chromosome (BAC) vectors from a Red Sea metagenomic library were screened using soft agar overlay with two indicator bacteria C. violaceum and A. tumefaciens KYC55. These screening methods suggest that QSI ability is common in the marine environment. The results indicate that the most active compound (14-A5) found in this study, possesses not only the ability to disrupt QS signaling pathways, but is also able to reduce biofilm formation of P. aeruginosa and A. baumannii. Indeed this active, synthesized compound (MetProDKP) shows anti- biofilm properties against P. aeruginosa PAO1 strain (the total surface biofilm bio-volume dropped by up to 97.2%). In order to fully unravel the mechanism of the reported inhibition activity, additional research endeavors are still required. This study validates that the presented functional screening technique for QSI metabolic activities enables us to further advance our understanding about the occurrence of QSI molecules in the marine environment.