Fig. 2

Elimination of the apramycin resistance gene in the host strain genome. a Diagram of the integrative pTES-Tox plasmid. b Diagram of the pTES-Tox plasmid backbone deletion by the action of Cre recombinase (modified from [33]). c PCR amplification of the toxin gene (Tox) with primers LS-008 and LS-009 (1) and the apramycin resistance gene (Apra) with primers LS-113 and LS-114 (2) from S. lividans genomic DNA before, S. lividans ∆TA-pTES-Tox (−), and after, S. lividans ∆TA-Tox (+), Cre activity