Self-produced exopolysaccharide is a signal that stimulates biofilm formation in Pseudomonas aeruginosa

Yasuhiko Irie, Bradley R Borlee, Jennifer R O'Connor, Preston J Hill, Caroline S Harwood, Daniel J Wozniak, Matthew R Parsek

Research output: Contribution to journalArticlepeer-review

218 Citations (SciVal)


Bacteria have a tendency to attach to surfaces and grow as structured communities called biofilms. Chronic biofilm infections are a problem because they tend to resist antibiotic treatment and are difficult to eradicate. Bacterial biofilms have an extracellular matrix that is usually composed of a mixture of polysaccharides, proteins, and nucleic acids. This matrix has long been assumed to play a passive structural and protective role for resident biofilm cells. Here we show that this view is an oversimplification and that the biofilm matrix can play an active role in stimulating its own synthesis. Working with the model biofilm bacterium Pseudomonas aeruginosa, we found that Psl, a major biofilm matrix polysaccharide for this species, acts as a signal to stimulate two diguanylate cyclases, SiaD and SadC, to produce the intracellular secondary messenger molecule c-di-GMP. Elevated intracellular concentrations of c-di-GMP then lead to the increased production of Psl and other components of the biofilm. This mechanism represents a unique positive feedback regulatory circuit, where the expression of an extracellular polysaccharide promotes biofilm growth in a manner analogous to autocrine signaling in eukaryotes.
Original languageEnglish
Pages (from-to)20632–20636
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number50
Publication statusPublished - 11 Dec 2012


  • Bacterial Proteins
  • Base Sequence
  • Biofilms
  • Cyclic GMP
  • DNA, Bacterial
  • Escherichia coli Proteins
  • Extracellular Matrix
  • Feedback, Physiological
  • Genes, Bacterial
  • Phosphorus-Oxygen Lyases
  • Polysaccharides, Bacterial
  • Pseudomonas aeruginosa
  • Second Messenger Systems
  • Signal Transduction


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