Pyoverdin production is significantly increased at basic pH and plays a major role in the virulence of P. aeruginosa. (A) Production of pyoverdin normalized to cell density in P. aeruginosa PAO1 grown in liquid NGM at varying pH. n = 3, *p < 0.05 between Pi25 mM, pH 7.5 and Pi25 mM, pH7.5 +Fe3+, 100 μM. (B) Effect of pH changes on pyoverdin production and growth (inserted panel) in P. aeruginosa PAO1 at high Pi concentration (25 mM). (C) QRT-PCR demonstrating enhanced expression of iron-related but not phosphate- and QS-related genes. (D) PAO1 mutant deficient in the production of pyoverdin and pyochelin (ΔPvdD/ΔPchEF) is significantly attenuated in lethality in mice at pH 7.5. Mice were subjected to hepatectomy and intestinal injection with either wtPAO1 or its derivative mutant ΔPvdD/ΔPchEF. All mice were given 25 mM potassium phosphate buffered to pH 7.5 in their drinking water. Results were performed in duplicate. Cumulative survival is represented as Kaplan-Meyer survival curves, n = 10/group, p < 0.05, Log-Rank (Mantel-Cox).
Romanowski et al. BMC Microbiology 2011 11:212 doi:10.1186/1471-2180-11-212