Current Microbiology

, Volume 34 , Issue 4 , pp 238 –243

A Study of Iron Acquisition Mechanisms of Legionella pneumophila Grown in Chemostat Culture

  • Brian W.  James
  • W. Stuart  Mauchline
  • P. Julian  Dennis
  • C. William  Keevil

DOI: 10.1007/s002849900176

Cite this article as:
James, B., Mauchline, W., Dennis, P. et al. Curr Microbiol (1997) 34: 238. doi:10.1007/s002849900176

Abstract.

We recently demonstrated that the virulence of a clinical isolate of Legionella pneumophila is significantly attenuated when cultured in an iron-limited environment. In this study the influence of iron limitation on the expression of enzyme activities and iron-transport mechanisms was investigated. Expression of the important pathogenicity factor, the zinc metalloprotease, was reduced fivefold in response to iron limitation. Ferric citrate reductase activity was demonstrated in both iron-limited and replete cell fractions. Activity was located principally in the cytoplasm and periplasm, and was not enhanced by iron restriction. Optimum activity was observed with NADPH as reductant. Siderophores were not elaborated under these culture conditions. Iron-loaded transferrin enhanced the growth of steady-state, iron-limited cultures, demonstrating that transferrin represents a potentially important iron source for L. pneumophila in vivo. Although cell surface transferrin receptors were not detected, in vitro experiments demonstrated digestion of transferrin by the zinc metalloprotease activity of culture supernatants.

Copyright information

© Springer-Verlag New York Inc. 1997

Authors and Affiliations

  • Brian W.  James
    • 1
  • W. Stuart  Mauchline
    • 1
  • P. Julian  Dennis
    • 1
  • C. William  Keevil
    • 1
  1. 1.Centre for Applied Microbiology & Research, Porton Down, Salisbury, Wiltshire SP4 0JG, UK GB