Immunoblot analysis of the heterologous S. aureus Spx content in B. subtilis. Lanes A and B, LUW362 (spxΩpMUTIN2 amyE::spxBS); lanes C and D, LUW428 (spxΩpMUTIN2 amyE::spxSA); lanes E and F, LUW442 (spxΩpMUTIN2 ΔyjbH amyE::spxSA/pCW7_yjbHSA) before (lanes A, C, E) and after (lanes B, D, F) diamide treatment.