Fig. 2.

(A) Scheme representing the replacement of slgZ in the chromosome of S. lydicus (wild type [WT]) with the apramycin resistance cassette. aac(3)IV, apramycin resistance gene; hyg, hygromycin resistance gene; bla, β-lactamase gene. (B) UPLC analysis of mutant SLMZ (upper panel) and mutant SLMZ complemented by plasmid pEM4TslgZ (lower panel). AU, arbitrary units. (C) Antibiotic activity of streptolydigin (1) and streptolydigin B (2) against S. albus. Each paper disk was soaked with 2 μg of the corresponding compound. Control (C), without antibiotic. (D) Effect of slgZ, slgM, and slgZ-slgM overexpression in S. lydicus on streptolydigin production. Cultures were performed on R5A solid media, and streptolydigin production was determined by high-performance liquid chromatography (HPLC) analysis. Experiments were run in triplicate.