Figure 4. σ^AntA is required for the biosynthesis of antimycins.

(A) S. albus S4 strains challenged with Candida albicans. The ΔantA null mutant shows dramatically reduced bioactivity compared to the wild-type strain and the complemented strain (ΔantA/pIJ10257-antA). The residual bioactivity of the ΔantA mutant is due to the continued production of candicidin, a second antifungal compound. (B) HPLC analysis of metabolites produced by S. albus S4 strains. Antimycins were only detected in extracts prepared from the wild-type and the ΔantA/pIJ10257-antA strains, and not the ΔantA null mutant.