If the compound shows growth inhibition of C. violaceum, can I still proceed to determine the anti-quorum sensing effects? How can I quantify the production of violacein production?
Hello Lim Wei Gene,
There are a few other ways to show the anti-QS effect of a molecule. The CV strain makes use of short-chain AHLs (C4- and C6 AHLs) for QS. You can also try using the Agrobacterium tumefaciens NTL4 or NT1 reporter strain which detects the presence of long-chain AHLs (C8- and C-12 AHLs). The latter contains a plasmid that induces the expression of the B-Gal gene (due to the presence of AHL molecules) resulting in the hydrolysis of X-Gal on a solid medium, producing light-blue colored colonies or bacterial growth. While in the absence of this enzyme (no QS as a result of no or low concentration of AHL molecules), the colonies appear white in color. You can also quantify this activity by extracting AHLs from your culture, then inducing NTL4 cells with the isolated AHLs, and performing a B-galactosidase assay to determine the activity of B-gal produced as a result of induction by the AHL molecules. Thus, you can detect QS by the virtue of AHL production through the B-gal activity.
For more reference, you can read these 2 articles published by my colleagues Dr. Sunil Kumar Bose and Dr. Karuna Sharma.
Terpinen-4-ol attenuates quorum sensing regulated virulence factors and biofilm formation in Pseudomonas aeruginosa.
Sustained release of Zingerone from polymeric nanoparticles: An anti-virulence strategy against Pseudomonas aeruginosa.
Good luck!
