Variations in structural and plasmid profiles of starved Shigella in seawater

In this study, we incubated three strains of Shigella (Shigella sonnei (S1), Shigella boydii(S2) and Shigella flexneri (S3)) in seawater microcosms (at room temperature and at 4°C) for eight months and we studied the modification of the proteins secreted, cytosolicand inner membrane profiles and their composition in fatty acids. Plasmid profiles were also investigated. Plasmids profiles analysis showed that S. boydii (S2) and S. flexneri (S3) did not lose any of their plasmids. In addition, fatty acids composition of Shigella under stress conditions was modified. Proteins secreted, cytosolic and inner membrane of stressed bacteria was changed and these modifications were manifested by the appearance and/or disappearance of bands.   Key words: Shigella, seawater, starvation, plasmids, proteins, fatty acids.