HPLC analysis of heterogeneous expression of thuringiensin in recombinant BMB0542 (25-kb insert). A, trace of the supernatant from strain CT-43 (positive control). B, trace of the supernatant from recombinant BMB0542 (25-kb insert). C, trace of the supernatant mixture from recombinant BMB0542 (25-kb insert) and strain CT-43. D, trace of supernatant from host strain BMB171 (negative control). The characteristic peak of thuringiensin is indicated by an arrow. The red lines were produced by the MS system to fix on the range of a peak and facilitate the peak area calculation by the (MS soft, Varian workstation). AU, absorbance unit.