Figure 4. Excision capacities of Acidithiobacillus ICE and IME.

A Agarose gel electrophoresis of end point PCR products generated with primers for attL, attR, attB and attI showing excisive recombination of ICE-1, ICE-2, ICE-3 and IME-1 in cognate A. caldus strains ATCC51756, F, CSH12 and F respectively (A). DNA damaging agents effect on ICE-2 excision frequency (B). Relative fold induction of the integrated form (attR) and the excised form (attB, attI) of ICE-2 in the type strain assessed by real time PCR upon treatment with Mit C or mitomycin C (1 µg/ml, 16 hs), light purple; UV-C radiation (200 J/m², 5 min), light green; and Fe³⁺ or ferric iron (250 mM, 45 min), orange, with respect to control conditions (no DNA damaging treatment), dark purple. Abbreviations: ICE, integrative conjugative element; IME, integrative mobilizable element.