Characterization of the catecholate indicator strain S. typhimurium TA2700 as an ent fhuC double mutant

Abstract

The Salmonella typhimurium strain TA2700 is a good indicator strain for enterobactin and other catecholate siderophores. It is unable to use hydroxamate siderophores and α-keto-/α-hydroxyacids and is resistant to albomycin, a sideromycin. By using a MudPQ mapping set the hydroxamate uptake mutation in TA2700 was located in the 2–5 Cs region. Using transduction with known markers, the mutation was mapped more precisely near 4 Cs. By complementation with different fhu genes from Escherichia coli, a complementation of the hydroxamate iron utilization phenotype was observed in fhuC-complemented TA2700 only. All fhuC-complemented strains were also sensitive to albomycin. A fhuC + transductant of S. typhimurium TA2700 was cross-fed by α-ketoisocaproic acid. By cotransduction with known and unknown markers near 13 Cs an ent mutation of S. typhimurium TA2700 was mapped.