Phenotypic effect of <i>SCO4676</i> and <i>SCO4677</i> deletion.

<p>A) Phenotypic comparison of strains grown on SFM (soy flour supplemented with mannitol) for 48 h. Left image: top of plate; right image: bottom of the same plate. Strain descriptions for the left plate, starting from the top left are as follows: wild type (M145); apramycin resistance-marker containing <i>SCO4676</i> deletion mutant (Δ<i>4676::apr</i>); Δ<i>4676</i> with the apramycin resistance cassette removed to create an in-frame, markerless mutant (Δ<i>4676</i> unmarked); and an apramycin resistance-marker containing <i>SCO4677</i> deletion mutant (Δ<i>4677::apr</i>). B) Enhanced actinorhodin production by the <i>SCO4676</i> deletion mutant (carrying the empty integrating plasmid pIJ82), relative to the wild type empty plasmid-carrying strain (M145+pIJ82), as determined by measuring the A₆₃₃, and normalizing to the dry cell weight (in mg). This enhanced antibiotic production could be partially complemented by introduction of wild type <i>SCO4676</i> on the integrating plasmid vector pIJ82. The data presented represent the average of three independent cultures, with each analyzed in duplicate; error bars indicate standard error. Asterisks indicate statistically significant differences (* = <i>P-</i>value <0.05; *** = <i>P-</i>value <0.001).