Role of pyocyanin in the acquisition of iron from transferrin.

AUTOR(ES)

Cox, C D

RESUMO

Pseudomonas aeruginosa produces a blue pigment called pyocyanin. In the presence of oxidizable substrates, bacteria reduce this pigment to a colorless product, leukopyocyanin. Pyocyanin can also be nonenzymatically reduced by NADH. Leukopyocyanin formed by cell- or NADH-mediated reduction nonenzymatically reduces oxygen or Fe(III). Pyocyanin-dependent iron reduction by whole bacterial cells was measured by the formation of the ferrous-ferrozine complex. In addition, leukopyocyanin reduced chelated Fe(III) including ferric iron in complex with transferrin, the serum iron-binding protein. High-pressure liquid chromatography was used to display the reductive removal of iron from transferrin and the accumulation of iron in the ferrous-ferrozine complex. Pyocyanin stimulated the accumulation of 55Fe from [55Fe]transferrin when it was added to bacteria incubated under low-oxygen conditions. Although bacteria grown in the presence of 100 microM FeCl3 reduced pyocyanin just as rapidly as iron-limited bacteria, these cells did not accumulate iron in the presence or absence of pyocyanin. Therefore, P. aeruginosa participates indiscriminantly in the reduction of pyocyanin, but soluble or available iron generated by the pyocyanin is taken up specifically by iron-limited bacteria.

Documentos Relacionados

• Uptake and release of iron from human transferrin.
• Occupancy of the iron binding sites of human transferrin.
• Acquisition of iron from transferrin and lactoferrin by the protozoan Leishmania chagasi.
• Siderophore-mediated iron acquisition from transferrin by Pseudomonas aeruginosa.
• Enhancement of Neisseria meningitidis infection in mice by addition of iron bound to transferrin.