FIG. 6.

Complementation of ΔfslA mutant. (A) Siderophore expression. GR7 and transformants with vector alone (pFNLTP6) or with the fslA⁺ plasmid pGIR458 were grown overnight in CDM-Fe, and the specific CAS activity of culture supernatants was determined. LVS transformants were tested as a control. (B and C) Promotion of growth on iron-limiting agar by cross-feeding of siderophore. GR7 was seeded as an indicator strain on iron-limiting CDM agar, and cultures of test strains were spotted on the plate. Growth halo formation around the test strains was recorded after 3 days at 37°C. The test strains used were LVS and GR7 (B) and GR7 carrying vector plasmid pFNLTP6 or fslA⁺ complementing plasmid pGIR458, and LVS carrying pFNLTP6 (C).