Figure 4: SDS-PAGE band patterns of three different culture conditions in strain K115 (type IB). L: ladder, An: anaerobic culture, Mi: microaerophilic culture, O2: aerobic culture. SDS-PAGE analysis of the three extracts indicated a high degree of similarity between the anaerobic (An) and microaerophilic (Mi) lysates but substantial differences between these (An and Mi) and the aerobic extract (O2). In particular, the 12–15 kDa segment of the gel showed a marked difference between both, with negligible proteins visible in the aerobic extract. To gain insight into the proteins that may be involved in this change to anaerobic growth, this segment of the gel was removed, digested with trypsin, and subjected to LC-MS/MS as described in the Materials and Methods section.