Optometry Research Today is a free monthly online journal that collates and summarizes the latest research about Optometry, including details on myopia, optometric practice, therapy. | ||||||||
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Quorum sensing regulation of adhesion in Serratia marcescens MG1 is surface dependent.Labbate M, Zhu H, Thung L, Bandara R, Larsen MR, Willcox MD, Givskov M, Rice SA, Kjelleberg S School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia, Centre for Marine Biofouling and Bio-Innovation, University of New South Wales, Sydney, New South Wales, Australia, The Institute for Eye Research and School of Optometry, Sydney, New South Wales, Australia, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark, Centre for Biomedical Microbiology, BioCentrum-DTU, The Technical University of Denmark, Kongens Lyngby, Denmark. Serratia marcesens is an opportunistic pathogen and a major cause of ocular infections. In previous studies with S. marcescens MG1, we have shown that biofilm maturation and sloughing were regulated by N-acyl homoserine lactone (AHL) based quorum sensing (QS). Given the importance of adhesion in initiating biofilm formation and infection, the primary goal of this study was to determine whether QS is important in adhesion to both abiotic and biotic surfaces, as assessed by determining the degree of attachment to hydrophilic tissue culture plates, and human corneal epithelial (HCE) cells. Our results demonstrate that while adhesion to the abiotic surface was AHL-regulated, adhesion to the HCE biotic surface was not. Type I fimbriae were identified as the critical adhesin for non-QS mediated attachment to the biotic HCE surface but played no role in adhesion to the abiotic surface. While we were not able to identify a single QS-regulated adhesin essential for attachment to the abiotic surface, four AHL-regulated genes involved in adhesion to the abiotic surface were identified. Interestingly, two of these genes, bsmA and bsmB, were also shown to be involved in adhesion to the biotic surface in a non-QS controlled fashion. Therefore, the expression of these two genes appear to be co-controlled by regulators other than the QS system to mediate attachment to HCE cells. We also report that QS in S. marcescens regulates other potential cell surface adhesins including exopolysaccharide and the outer membrane protein OmpX. We submit that S. marcescens MG1 utilises different regulatory systems and adhesins in attachment to biotic vs. abiotic surfaces, and that QS is a main regulatory pathway in adhesion to the abiotic but not the biotic surface. Published 22 January 2007 in J Bacteriol.
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