Fig. 2
The mupR mutation reduces toxin production by the SH1000 strain. a A representative image of a western blot on TCA precipitated bacterial supernatant using anti-alpha toxin antibodies. On average we found the wild-type mupS strain produced twofold more alpha toxin compared to the mupR strain. b Coomassie stained SDS-PAGE gel with butanol extractions of bacterial supernatant, containing the PSMs. On average we found the wild-type mupS strain produced 3.4-fold more PSM compared to the mupR strain. c Over-expression of the pmtC gene, which encodes one of the ATP binding proteins of the PSM secretory system, Pmt, in the wild-type SH1000 strain causes a reduction in the abundance of the PSM in the S. aureus supernatant. An Agr mutant has been provided as a control. d The intra- and extra-cellular levels of PSMs were pooled to compare the overall levels of PSM production where on average the wild-type strain produced 3.2-fold more PSMs. A full length SDS-PAGE gel is provided in Additional file 1: Figure S3 to illustrate why we only provide a ‘letter-box’ snap-shot of the gels here