That different isoelectropherotypes of polypeptides in 2DE gels do not always
That different isoelectropherotypes of polypeptides in 2DE gels do not always arise from true post translational modifications, but also from the 2-DE procedure itself [31,32]. The outer surface of bacteria is of great importance to the understanding of bacterial pathogenesis. Elements of the surface are implicated in bacterial defense mechanisms and virulence related functions e.g. adhesion, invasion, direct injury, and induction of septic shock. There is no information available with respect to surface proteins of this medically important bacterium. In the present study, several of the surface proteins and those over-expressed in CMM grown cells were largely assigned putative function in amino acid transport and metabolism [see Additional file 1], suggesting that this organism PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/24292380 is adapted to protein rich environment of host tissue. Together, these identified and Omeprazole sodium predicted proteins could be useful targets for the development of improved vaccines against gangrenous infections. Two of the surface proteins of C. perfringens, ornithine carbamoyltransferase and phosphoglycerate kinase have also been identified as immunogenic proteins in the outer surface protein preparation of S. agalactiae and S. pyogenes [24,25]. Curiously, sera directed against the two proteins were shown to protect neonatal animals from S. agalactieae infection in a passive immunization experiment. Inearlier studies, phosphoglycerate kinase was reported on the surface of S. pneumoniae, was antigenic in humans, and elicited protective immune responses in mouse model  [see Additional file 6]. Also in Schistosoma mansoni, phosphoglycerate kinase has been identified as a protective antigen . Another surface protein, EF-G, identified in this study was found to be immuno-reactive against sera from broiler chicken immune to necrotic entritis . The protein was secreted into the culture supernatant and unique to virulent C. perfringens strain CP4 causing necrotic entritis. Notably, EF-G is regulated by the VirR-VirS virulence regulon of C. perfringens . Moreover, EF-G has been demonstrated as an immunogenic protein and was identified in both cell surface and extracellular fraction of B. anthracis [9,29]. Further, choloylglycine hydrolase family protein, cell wall-associated serine proteinase, and rhomboid family protein can be excellent surface protein markers for specific detection of C. perfringens from environment and food as they share very low percent amino acid sequence identity with there nearest homologs (<50 ) and are conserved among the C. perfringens strains [see Additional file 6]. Some of the surface proteins from C. perfringens ATCC13124 showed metabolic functions that would typically place them in the cytoplasm. Moreover, except for N-acetylmuramoyl-L-alanine amidase and cell wall-associated serine proteinase, these proteins have no N-terminal signal peptide and do not possess the canonical grampositive anchor motif LPXTG [see Additional file 7]. Several surface-associated cytoplasmic proteins reported in this study were also detected on the bacterial surface in previous proteomic analysis [see Additional file 6]. For example, phosphoglycerate kinase was reported on the surface of S. pneumoniae , S. agalactiae , S. pyogenes , and S. oralis [see Additional file 6] and also as secreted protein in B. anthracis . Increasing number of reports have shown presence of proteins on the surface of Gram positive bacteria or secreted into the med.