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Archives of Microbiology

, Volume 166, Issue 5, pp 301–307 | Cite as

Iron-limited growth and kinetics of iron uptake in Magnetospirillum gryphiswaldense

  • Dirk Schüler
  • E. Baeuerlein
Original paper

Abstract

Growth and magnetite formation in Magnetospirillum gryphiswaldense MSR-1 were found close to the maximum at an extracellular iron concentration of 15–20 μM. Ferrous iron was incorporated by a slow, diffusion-like process. Several iron chelators including various microbial siderophores were unable to promote transport of iron into the cells. In contrast, spent culture fluids stimulated the uptake of ferric iron in iron-depleted cells at a high rate, whereas fresh medium and transport buffer were unable to promote iron uptake. However, no siderophore-like compound could be detected in spent culture fluids by the Chrome Azurol S assay. Ferric iron uptake followed Michaelis-Menten kinetics with a K m of 3 μM and a V max of 0.86 nmol min–1 (mg dry weight)–1, suggesting a comparatively low-affinity, but high-velocity transport system. Iron incorporation was sensitive to 2,4-dinitrophenol and carbonylcyanide-m-chlorophenylhydrazone, indicating an energy-dependent transport process.

Key words Magnetic bacteria Magnetospirillum gryphiswaldense Magnetite biomineralization Iron uptake 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Dirk Schüler
    • 1
  • E. Baeuerlein
    • 1
  1. 1.Max-Planck-Institut für Biochemie, Abteilung Membranbiochemie, D-82152 Martinsried, Germany Tel. +49-89-85782359; Fax +49-89-85783777 e-mail: baeuerlein@vms.biochem.mpg.deDE

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