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

Subinhibitory concentrations of the cationic antimicrobial peptide colistin induce the pseudomonas quinolone signal in Pseudomonas aeruginosa

“…Its production results in upregulation of virulence factors such as phenazines and rhamnolipid, which are important for pathogenesis in several virulence models (Gallagher & Manoil, 2001;Mahajan-Miklos et al, 1999;Mavrodi et al, 2001;Pesci et al, 1999;Rahme et al, 2000). PQS is also known to promote biofilm formation and DNA release in P. aeruginosa, when iron is limiting (Yang et al, 2007). While our genetic and phenotypic data would suggest that subinhibitory concentrations of colistin influence biofilm formation in P. aeruginosa, no significant difference was observed in biomass using flow cells (data not shown).…”

“…Expressed in cells that form the stalk of maturing biofilms, PQS contributes to the formation of the mushroom structure and secretion of extracellular DNA (Yang et al, 2007). Transcriptome analysis revealed regulation of several genes involved in biofilm formation and maturation in response to subinhibitory concentrations of colistin (Fig.…”

P. aeruginosa Biofilms in CF Infection

“…The extracellular DNA has been localized within the biofilm structure and varies temporally as well as spatially. Early biofilms show large amounts of extracellular DNA on the substratum and coating the microcolonies, while in a mature biofilm, it is present primarily in the stalks of mushroom structures [42]. The source of extracellular DNA has been proposed to be due to either prophage-induced cell lysis or the release of membrane vesicles [42].…”

“…Exposure of P. aeruginosa to DNaseI prevented biofilm development in a flow-through model system and dissolved young biofilms [41]. Further research with QS mutants in lasI and rhlI, the genes that direct the synthesis of the autoinducers 3O-C 12 -HSL and C 4 -HSL, respectively, determined that QS is important in regulating extracellular DNA release during both planktonic and biofilm growth [42]. Furthermore, PQS, the third QS autoinducer signal, was linked to extracellular DNA release during biofilm development [42].…”

“…Further research with QS mutants in lasI and rhlI, the genes that direct the synthesis of the autoinducers 3O-C 12 -HSL and C 4 -HSL, respectively, determined that QS is important in regulating extracellular DNA release during both planktonic and biofilm growth [42]. Furthermore, PQS, the third QS autoinducer signal, was linked to extracellular DNA release during biofilm development [42]. The extracellular DNA has been localized within the biofilm structure and varies temporally as well as spatially.…”