Genetic and biochemical evidence for a siderophore-dependent iron transport system in Corynebacterium diphtheriae.

AUTOR(ES)

Russell, L M

RESUMO

During growth under conditions of iron deprivation, Corynebacterium diphtheriae secreted a siderophore into the culture medium. This extracellular siderophore was necessary for rates of iron uptake at pH 8.0 by C. diphtheriae C7 and related strains. We isolated a mutant of C. diphtheriae C7(beta), strain HC6, which did not make the corynebacterial siderophore. Strain HC6 grew very poorly, even under high-iron conditions, and had a severe defect in iron transport. Both growth and iron uptake by strain HC6 were greatly stimulated by the corynebacterial siderophore. We used strain HC6 to develop a bioassay for the corynebacterial siderophore and to look for other potential siderophores for C. diphtheriae. Among the purified phenolate and hydroxamate siderophores tested, only aerobactin was able to stimulate the growth of strain HC6. Partial purification of the corynebacterial siderophore was achieved. The siderophore did not give positive reactions in the Arnow test for phenolates or the Csaky test for hydroxamates and may have a novel chemical structure.

Documentos Relacionados

• Identification of a DtxR-Regulated Operon That Is Essential for Siderophore-Dependent Iron Uptake in Corynebacterium diphtheriae
• Initial characterization of the ferric iron transport system of Corynebacterium diphtheriae.
• The Yersiniabactin Biosynthetic Gene Cluster of Yersinia enterocolitica: Organization and Siderophore-Dependent Regulation
• Screening for Corynebacterium diphtheriae.
• Analysis of a DtxR-Regulated Iron Transport and Siderophore Biosynthesis Gene Cluster in Corynebacterium diphtheriae