FIG. 4.

Genetic complementation of the 531A(pJHC1::Ω) mutant with the angB gene and its 3′-deleted derivative. (A) Detection of anguibactin by using CAS agar plates (40). The identity of anguibactin as the CAS-reactive product was verified by bioassays as previously described (49). Strains tested were as follows: panel 1, WT, 531A(pJHC1/pTW99); panel 2, 531A(pJHC1::Ω/pTW99); panel 3, 531A(pJHC1::Ω/pTW200); panel 4, 531A(pJHC1::Ω/pTW201); panel 5, S531A-1(pTW99); and panel 6, S531A-1(pTW201). Strains in panels 1, 2, and 5 carry pTW99 as a vector control. S531A-1 is a plasmidless derivative of 531A. (B) Production of DHBA by the same strains grown to stationary phase in complete minimal medium. DHBA production was analyzed by using the Arnow reaction (6) and calibrating the assay with a DHBA standard. The presence of DHBA was verified by bioassays with Salmonella strains containing enb1 and enb7 mutations according to the method of Pollack and Neilands (33).