Inhibition and dispersal of Agrobacterium tumefaciens biofilms by a small diffusible Pseudomonas aeruginosa exoproduct(s
- PDF / 490,190 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 9 Downloads / 191 Views
ORIGINAL PAPER
Inhibition and dispersal of Agrobacterium tumefaciens biofilms by a small diffusible Pseudomonas aeruginosa exoproduct(s) Michael E. Hibbing • Clay Fuqua
Received: 30 July 2011 / Revised: 12 October 2011 / Accepted: 14 October 2011 / Published online: 22 November 2011 Ó Springer-Verlag 2011
Abstract Environmental biofilms often contain mixed populations of different species. In these dense communities, competition between biofilm residents for limited nutrients such as iron can be fierce, leading to the evolution of competitive factors that affect the ability of competitors to grow or form biofilms. We have discovered a compound(s) present in the conditioned culture fluids of Pseudomonas aeruginosa that disperses and inhibits the formation of biofilms produced by the facultative plant pathogen Agrobacterium tumefaciens. The inhibitory activity is strongly induced when P. aeruginosa is cultivated in iron-limited conditions, but it does not function through iron sequestration. In addition, the production of the biofilm inhibitory activity is not regulated by the global iron regulatory protein Fur, the ironresponsive extracytoplasmic function r factor PvdS, or three of the recognized P. aeruginosa quorum-sensing systems. In addition, the compound(s) responsible for the inhibition and dispersal of A. tumefaciens biofilm formation is likely distinct from the recently identified P. aeruginosa dispersal factor, cis-2-decenoic acid (CDA), as dialysis of the culture fluids showed that the inhibitory compound was larger than CDA and culture fluids that dispersed and inhibited biofilm formation by A. tumefaciens had no effect on biofilm formation by P. aeruginosa.
Communicated by John Helmann.
Electronic supplementary material The online version of this article (doi:10.1007/s00203-011-0767-9) contains supplementary material, which is available to authorized users. M. E. Hibbing C. Fuqua (&) Department of Biology, Indiana University, 1001 E. 3rd St., Jordan Hall 142, Bloomington, IN 47405-1847, USA e-mail: [email protected]
Keywords
Biofilms Inhibition Dispersal Iron
Introduction There is a growing appreciation that bacteria in many environments exist primarily as multicellular communities known as biofilms. These bacterial aggregates assemble at interfaces and generally are encased in an extracellular polymeric matrix (Sutherland 2001; Whitchurch et al. 2002). In contrast to planktonically growing bacteria, the cells in a biofilm are typically more recalcitrant to antimicrobial treatment and predatory grazing, capable of maintaining extremely high local cell densities, and thus able to potentially facilitate the expression of quorumsensing controlled functions and horizontal gene transfer (Maeda et al. 2006; Horswill et al. 2007). These characteristics are of particular concern in many medically relevant contexts where biofilms often play a role in implant-associated infections, waterborne diseases, and the establishment of chronic infections (Costerton et al. 1999; Rather 2005; Lim et al. 2006).
Data Loading...
