Quorum sensing is a regulatory process used by bacteria for controlling gene expression in response to increasing cell density.
1 This regulatory process manifests itself with a variety of phenotypes including biofilm formation and virulence factor production.
2 Coordinated gene expression is achieved by the production, release, and detection of small diffusible signal molecules called autoinducers. The N-
acylated homoserine lactones (AHLs) comprise one such class of autoinducers, each of which generally consists of a fatty acid coupled with homoserine lactone (HSL). AHLs vary in acyl group length (C
4-
C
18), in the substitution of C3 (hydrogen, hydroxyl, or oxo group) and in the presence or absence of one or more carbon-
carbon double bonds in the fatty acid chain. These differences confer signal specificity through the affinity of transcriptional regulators of the LuxR family.
3 N-
cis-hexadec-9Z-enoyl-L-Homoserine lactone is a long-
chain AHL that functions as a quorum sensing signaling molecule in strains of
S. meliloti.
4,5,6,7 Regulating bacterial quorum sensing signaling can be used to inhibit pathogenesis and thus, represents a new approach to antimicrobial therapy in the treatment of infectious diseases.
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1. González, J.E., and Keshavan, N.D. Messing with bacterial quorum sensing Microbiol. Mol. Biol. Rev. 70(4),859-875(2006).
2. Gould, T.A., Herman, J., Krank, J., et al. Specificity of acyl-homoserine lactone syntheses examined by mass spectrometry J. Bacteriol. 188(2),773-783(2006).
3. Penalver, C.G.N., Morin, D., Cantet, F., et al. Methylobacterium extorquens AM1 produces a novel type of acyl-homoserine lactone with a double unsaturated side chain under methylotrophic growth conditions FEBS Lett. 580(2),561-567(2006).
4. Teplitski, M., Eberhard, A., Gronquist, M.R., et al. Chemical identification of N-acyl homoserine lactone quorum-sensing signals produced by Sinorhizobium meliloti strains in defined medium Arch. Microbiol. 180(6),494-497(2003).
5. Gao, M., Chen, H., Eberhard, A., et al. sinI- and expR-dependent quorum sensing in Sinorhizobium meliloti J. Bacteriol. 187(23),7931-7944(2005).
6. Marketon, M.M., Glenn, S.A., Eberhard, A., et al. Quorum sensing controls exopolysaccharide production in Sinorhizobium meliloti J. Bacteriol. 185(1),325-331(2003).
7. Marketon, M., Gronquist, M.R., Eberhard, A., et al. Characterization of the Sinorhizobium meliloti sinR/sinI locus and the production of novel N-Acyl homoserine lactones J. Bacteriol. 184(20),5686-5695(2002).
8. Cegelski, L., Marshall, G.R., Eldridge, G.R., et al. The biology and future prospects of antivirulence therapies Nat. Rev. Microbiol. 6(1),17-27(2008).
