Fig. 1. Schematic diagrams of (a) DFOB–desferrioxamine B, the free ligand of the siderophore ferrioxamine B; (b) FOB–the ferric complex of DFOB; (c) EDDHA–the free ligand of the synthetic ethylenediamine di-o-hydroxyphenylacetic acid; (d) FeEDDHA–the ferric complex of EDDHA.