Avermectin production and growth of wild-type strain ATCC31267 and <i>SAV577</i> mutant strains.

<p>(<b>A</b>) Comparison of avermectin production in various <i>S. avermitilis</i> strains grown in FM-I medium for 10 days. WT, wild-type strain ATCC31267. WT/pKC1139, ATCC31267 carrying control plasmid pKC1139. D576, <i>SAV576</i> deletion mutant. D577, <i>SAV577</i> deletion mutant. D577/pSET152-577, complementation strain of D577. WT/pKC1139-577, <i>SAV577</i> overexpression strain. D576-577, <i>SAV576-SAV577</i> double deletion mutant. (<b>B</b> and <b>C</b>) Effect of <i>SAV577</i> deletion on avermectin production (<b>B</b>) and growth (<b>C</b>) of <i>S. avermitilis</i> grown in soluble medium FM-II. Solid squares, ATCC31267; Solid circles, D577. Results are shown as mean ± SD for three independent experiments. **<i>P</i><0.01 and ***<i>P</i><0.001 as determined by Student's <i>t</i>-test. ns, not significant.