TABLE 3.
Trans-complementation assays of an mceC mutant, using purified forms of cyclic salmochelins, and dependence on the ferric-catecholate receptorsa
| E. coli strain | Complementation with plasmid
|
|||
|---|---|---|---|---|
| pJEM15 (wild type) | npB4 (mceC)
|
|||
| No addition | +MGE | +DGE | ||
| DH5α (fepA+fiu+cir+) | +++ | − | ++ | +++ |
| H1876 (fepA fiu cir) | ++ | − | − | − |
| H1875 (fepA fiu+cir) | +++ | − | ++ | +++ |
| H1594 (fepA+fiu cir+) | ++ | − | ± | ± |
a
Trans-complementation was performed by supplementing the previously seeded indicated strains with 3 μl of purified salmochelin (1 mM MGE or DGE). The antibacterial activity was measured and evaluated as described in Table 2 (± indicates a detectable but very low activity).