Analysis of GerRB-SGFP2 fusion protein expression in B. cereus spores of various strains. thirty micrograms protein in extracts from dormant spores of various B. cereus strains were separated on a 10% SDS-PAGE gel and western blots were probed with rabbit polyclonal anti-GFP antibody as described in Methods. The black arrow indicates the position of the expected 69 kDa GerRB-SGFP2 protein. Two nonspecific bands of ~100 kDa and ~55 kDa were also detected in all extracts. Notably, free SGFP2 at 27 kDa was not detected, in particular in extracts of spores carrying pHT315- PgerR-gerRB-SGFP2. The extracts run in the various lanes were from: lane 1, wild-type spores; lane 2, spores carrying pHT315; lane 3, spores carrying pHT315-PgerR-gerRB-SGFP2; lane 4, spores carrying pHT315-gerRB-SGFP2; lane M, prestained protein ladder.