Effects of iron on DNA release and biofilm development by Pseudomonas aeruginosa

TY - JOUR

T1 - Effects of iron on DNA release and biofilm development by Pseudomonas aeruginosa

AU - Yang, Liang

AU - Barken, Kim B

AU - Skindersoe, Mette E

AU - Christensen, Allan B

AU - Givskov, Michael

AU - Tolker-Nielsen, Tim

N1 - Keywords: Biofilms; DNA, Bacterial; Gene Expression Regulation; Genes, Reporter; Green Fluorescent Proteins; Iron; Operon; Pseudomonas aeruginosa; Quorum Sensing; Signal Transduction

PY - 2007

Y1 - 2007

N2 - Extracellular DNA is one of the major matrix components in Pseudomonas aeruginosa biofilms. It functions as an intercellular connector and plays a role in stabilization of the biofilms. Evidence that DNA release in P. aeruginosa PAO1 biofilms is controlled by the las-rhl and pqs quorum-sensing systems has been previously presented. This paper provides evidence that DNA release in P. aeruginosa PAO1 biofilms is also under iron regulation. Experiments involving cultivation of P. aeruginosa in microtitre trays suggested that pqs expression, DNA release and biofilm formation were favoured in media with low iron concentrations (5 microM FeCl(3)), and decreased with increasing iron concentrations. Experiments involving cultivation of P. aeruginosa in a flow-chamber system suggested that a high level of iron (100 microM FeCl(3)) in the medium suppressed DNA release, structural biofilm development, and the development of subpopulations with increased tolerance toward antimicrobial compounds. Experiments with P. aeruginosa strains harbouring fluorescent reporters suggested that expression of the pqs operon was induced in particular subpopulations of the biofilm cells under low-iron conditions (1 microM FeCl(3)), but repressed in the biofilm cells under high-iron conditions (100 microM FeCl(3)).

AB - Extracellular DNA is one of the major matrix components in Pseudomonas aeruginosa biofilms. It functions as an intercellular connector and plays a role in stabilization of the biofilms. Evidence that DNA release in P. aeruginosa PAO1 biofilms is controlled by the las-rhl and pqs quorum-sensing systems has been previously presented. This paper provides evidence that DNA release in P. aeruginosa PAO1 biofilms is also under iron regulation. Experiments involving cultivation of P. aeruginosa in microtitre trays suggested that pqs expression, DNA release and biofilm formation were favoured in media with low iron concentrations (5 microM FeCl(3)), and decreased with increasing iron concentrations. Experiments involving cultivation of P. aeruginosa in a flow-chamber system suggested that a high level of iron (100 microM FeCl(3)) in the medium suppressed DNA release, structural biofilm development, and the development of subpopulations with increased tolerance toward antimicrobial compounds. Experiments with P. aeruginosa strains harbouring fluorescent reporters suggested that expression of the pqs operon was induced in particular subpopulations of the biofilm cells under low-iron conditions (1 microM FeCl(3)), but repressed in the biofilm cells under high-iron conditions (100 microM FeCl(3)).

U2 - 10.1099/mic.0.2006/004911-0

DO - 10.1099/mic.0.2006/004911-0

M3 - Journal article

C2 - 17464046

SN - 1350-0872

VL - 153

SP - 1318

EP - 1328

JO - Microbiology

JF - Microbiology

IS - Pt 5

ER -