Monitoring Iron Uptake by Siderophores
Iron is an important element for almost all forms of life. In order to get access to this essential nutriment, Pseudomonads produce two major siderophores, pyoverdine PVD and pyochelin (PCH). Uptake of iron in bacterial cells can be monitored accurately using 55Fe. Bacteria cells are incubated in the presence of either PVD or PCH loaded with 55Fe. After incubation, extracellular iron ions are separated from those accumulated in the bacteria cells by either centrifugation or filtration on glass microfiber filters, for the PCH and PVD assays, respectively. 55Fe contained in the harvested cells on the filter or in the cell pellet is counted in scintillation cocktail. The number of moles of 55Fe transported can be determined using the specific activity of the radionuclide.
Key wordsSiderophore Pyoverdine Pyochelin Iron uptake Pseudomonas aeruginosa Iron homeostasis
This work was supported by CNRS and ANR grants (ANR-08-BLAN-0315-01 and 05-JCJC-0181-01).