This Article Full Text Full Text (PDF) Supplemental material Other Versions of this Article: JB.00505-07v1 189/17/6372    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Price-Whelan, A. Articles by Newman, D. K. Search for Related Content PubMed PubMed Citation Articles by Price-Whelan, A. Articles by Newman, D. K.

Pyocyanin Alters Redox Homeostasis and Carbon Flux through Central Metabolic Pathways in Pseudomonas aeruginosa PA14 ^,

Divisions of Biology,¹ Geological and Planetary Sciences,² Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125³

Received 2 April 2007/ Accepted 15 May 2007

The opportunistic pathogen Pseudomonas aeruginosa produces colorful, redox-active antibiotics called phenazines. Excretion of pyocyanin, the best-studied natural phenazine, is responsible for the bluish tint of sputum and pus associated with P. aeruginosa infections in humans. Although the toxicity of pyocyanin for other bacteria, as well as its role in eukaryotic infection, has been studied extensively, the physiological relevance of pyocyanin metabolism for the producing organism is not well understood. Pyocyanin reduction by P. aeruginosa PA14 is readily observed in standing liquid cultures that have consumed all of the oxygen in the medium. We investigated the physiological consequences of pyocyanin reduction by assaying intracellular concentrations of NADH and NAD⁺ in the wild-type strain and a mutant defective in phenazine production. We found that the mutant accumulated more NADH in stationary phase than the wild type. This increased accumulation correlated with a decrease in oxygen availability and was relieved by the addition of nitrate. Pyocyanin addition to a phenazine-null mutant also decreased intracellular NADH levels, suggesting that pyocyanin reduction facilitates redox balancing in the absence of other electron acceptors. Analysis of extracellular organic acids revealed that pyocyanin stimulated stationary-phase pyruvate excretion in P. aeruginosa PA14, indicating that pyocyanin may also influence the intracellular redox state by decreasing carbon flux through central metabolic pathways.

Published ahead of print on 25 May 2007.

Supplemental material for this article may be found at http://jb.asm.org/.

This article has been cited by other articles:

• Gorodetsky, A. A., Dietrich, L. E. P., Lee, P. E., Demple, B., Newman, D. K., Barton, J. K. (2008). DNA binding shifts the redox potential of the transcription factor SoxR. Proc. Natl. Acad. Sci. USA 105: 3684-3689 [Abstract] [Full Text]