SCREENING OF MARINE BACTERIUM VIBRIO ALGINOLYTICUS STRAIN AS05 FOR THE PRODUCTION OF N-ACYL HOMOSERINE LACTONE-BASED QUORUM SENSING SIGNALING MOLECULES

Abstract

Marine environments, including aquatic and coastal environments, are highly prevalent of marine bacteria with the highest levels of Vibrio species. Vibrios play a vital role in marine ecology associated with carbon and energy acquisition. The density-dependent quorum sensing (QS) system may regulate certain biological activities in marine bacteria. QS is a conversation system utilized by many bacterial communities to communicate and coordinate through different signalling molecules. N-acyl homoserine lactones (AHLs) are the most important QS signalling molecules widely produced by Gram-negative bacteria. This study aimed to investigate the detection and Identification of AHL-based QS signalling molecules produced by marine bacterium V. alginolyticus strain AS05 isolated from marine water of the Arabian Sea, Karachi, Pakistan. Marine medium Zobell-2216 was used to isolate bacterial strains. Moreover, 16S rRNA analysis was applied to identify AS05 strain. Agar plate bioassay was used to detect the production of AHL signalling molecules using Chromobacterium violaceum CV026 as a biosensor. The Identification of AHLs was made by reversed-phase thin-layer chromatography (RP-TLC) analysis. The NCBI-blast results revealed the identification of the isolated bacterial strain as Vibrio alginolyticus strain AS05 (OQ130030) member of the family of Vibrionaceae under the class of Gammaproteobacteria. The results of agar plate bioassay using CV026 as a biosensor strain revealed highly positive reactions for producing AHL signalling molecules. Moreover, two AHL molecules produced by AS05 bacterial strain were identified as C6-HSL and C-8HSL based on TLC analysis. This study reveals the detection and Identification of two different AHL signalling molecules produced by V. alginolyticus AS05 isolated from marine water of the Arabian Sea, Karachi, Pakistan. This study provides insight into investigating quorum-sensing signalling molecules in the Arabian Sea, Karachi, Pakistan, and marine bacterial species.