Fig. 1

Characterization of Hp 60190 outer membrane vesicles. a General scheme of the protocol for the isolation, concentration, and purification of Hp OMVs. b Hp OMVs observed by transmission electron microscopy. The yellow arrow indicates Hp vesicles (scale bar = 200 nm). c Nanoparticle tracking analysis (left) shows average concentration of OMVs (vesicles/ml) of a particular size (nm). Values in the table correspond to the quantification obtained by the nanoparticle tracking analysis (mean ± S.E.M.; n = 3) (right). d Electrophoretic profile of Hp 60190 total protein extracts and OMVs resolved on 12% SDS-PAGE and stained with Coomassie blue. St indicates molecular marker standards (kDa, left). e LC–ESI–MS/MS proteome analysis of whole bacteria and purified OMVs. The table shows the proteins identified as having the most abundant unique peptides (n = 3). f Venn diagram showing the number of proteins detected in the whole bacteria and purified OMVs