Proteomic analysis of typical and genetically altered strains of <i>Vibrio cholerae</i> serogroup O1, biovar El Tor

Abstract

Objective — comparative study of protein expression in typical and genetically altered Vibrio cholerae strains of O1 serogroup, biovar El Tor by means of proteomic analysis.Materials and methods. Clinical V. cholerae strains — typical strain, M106 (Astrakhan, 1970) and genetically altered one, M1509 (Moscow, 2012) — were used as model ones. Strains were cultivated in LB broth (pH7.2). Then, cell and exoprotein lysate fractions were obtained and investigated in 2D electrophoresis. Different protein stains were examined using mass spectrometry. Survivability of V. cholerae strains under osmotic and oxidative stresses was studied during incubation of the strains in 3 M NaCl solution or 20 mM H2O2 solution.Results and discussion. When analyzing cell lysates, significant differences in protein expression with known function between studied strains were not detected. The great majority of identified proteins in the lysates is functionally associated with carbohydrate metabolism, amino acid metabolism, and energy processes in a cell. At the same time, exoprotein fraction of M1509 genovariant contained increased amount of proteins (peroxidase, superoxide dismutase, thioredoxin, outer membrane proteins OmpW, OmpT) protecting the cells of cholera vibrio from effect of stress factors of the environment. Further study of the resistance to osmotic and oxidative stresses revealed better survivability in the genovariant when exposed to the stated factors.Conclusion. The data of proteomic analysis of the typical and genetically altered V. cholera strains, biovar El Tor, testify to high levels of expression of the proteins that provide for vibrio resistance to the effect of environmental stress factors in genovariants, which is possibly one of the causes of their wide dissemination. In addition, the results obtained will allow for identification of new biomarkers which can be used for differentiation of typical strains and genovariants of V. cholerae, biovar El Tor.

Keywords

• <i>vibrio cholerae</i>
• proteomic analysis
• adaptation proteins
• osmotic stress
• oxidative stress