Open AccessEvidence of autoinducer activity in naturally occurring biofilms
Author(s) -
McLean Robert J.C,
Whiteley Marvin,
Stickler David J,
Fuqua W.Claiborne
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb12653.x
Subject(s) - biofilm , quorum sensing , autoinducer , microbiology and biotechnology , bacteria , biology , pseudomonas aeruginosa , homoserine , virulence , agrobacterium tumefaciens , population , vibrio , reporter gene , gene , gene expression , biochemistry , genetics , transformation (genetics) , demography , sociology
N ‐Acyl homoserine lactone (AHL) molecules have been shown to act as mediators of population density‐dependent (quorum‐sensing) gene expression in numerous Gram‐negative bacteria. Functions associated with AHL include light production in Vibrio fischeri , expression of virulence factors in Pseudomonas aeruginosa , and conjugation in Agrobacterium tumefaciens . In nature, bacteria often grow as surface‐adherent biofilm communities. As biofilms typically contain high concentrations of cells, AHL activity and quorum‐sensing gene expression have been proposed as essential components of biofilm physiology. However, proof of AHL production within biofilms has heretofore been lacking. In this study we have employed a cross‐feeding assay, using A. tumefaciens A136 ( tra I:: lac Z) as an AHL‐responsive reporter strain, to show the presence of naturally occurring AHL production in aquatic biofilms growing on submerged stones. AHL was detected in living biofilms and biofilm extracts, but was not present in rocks lacking a biofilm. This represents the first report of AHL activity in naturally occurring biofilms.