Iron uptake in Pseudomonas
Pierre Cornelis, Christine Baysse and Sandra Matthijs
from: Pseudomonas: Genomics and Molecular Biology (Edited by: Pierre Cornelis). Caister Academic Press, U.K. (2008)
Abstract
Like all aerobic bacteria, pseudomonads need to take up iron via the secretion of siderophores which complex iron (III) with high affinity. Much progress has been made in the elucidation of siderophore-mediated high-affinity iron uptake by Pseudomonas, especially in the case of the opportunistic pathogen, P. aeruginosa. Fluorescent pseudomonads produce the high-affinity peptidic siderophore pyoverdine, but also, in many cases, a second siderophore of lesser affinity for iron. Some of the genes for the biosynthesis and uptake of these siderophores have been identified and the functions of the encoded proteins known. Iron uptake via siderophores is regulated at several levels, via the general iron-sensitive repressor Fur (Ferric Uptake Regulator), via extracytoplasmic sigma factors/anti-sigma factors or via other regulators. Since pseudomonads are ubiquitous microorganisms, it is not surprising to find in their genome a large number of genes encoding receptors for the uptake of heterologous ferrisiderophores or heme reflecting their great adaptability to diverse iron sources. Another exciting development is the recent evidence for a cross-talk between the iron regulon and other regulatory networks, including the diffusible signal molecule-mediated quorum sensing in P. aeruginosa read more ...