Proteomic analysis on the expression of outer membrane proteins of Vibrio alginolyticus at different sodium concentrations

The ability of osmoregulation is crucial to marine pathogens that always face the change of osmotic pressure when they shift between natural marine water-bodies and hosts. Previous studies indicated that the expressional patterns of outer membrane proteins (OMPs) changed when Gram-negative bacteria were transferred in different environments. In the present study, proteomic methodologies were used to investigate the expressional pattern of OMPs of Vibrio alginolyticus, a universal marine pathogen, at different Na+ concentrations. OmpW, OmpV, and Omp TolC were determined to be osmotic stress responsive proteins. Of the three proteins, importantly, OmpV and OmpW showed distinctly reverse changes to each other, indicating that the two proteins might be the two components varied with changed NaCl concentrations. In addition, our results suggest that closely related species of bacteria with available whole genomic databases should be applied after item microorganism species was used when proteins from a bacterium with unavailable whole genomic information were identified by PMF. Therefore, our results not only expand our knowledge on osmotic stress responsive proteins, but also provide valuable information for strategies on screening of these proteins.