The isolating Escherichia coli secretory outer membrane vesicles by using tangential-trans flow filtration

Among pathogenic bacteria, Gram-negative bacteria are more important. The secreting outer membrane vesicles of the bacteria are important role in physiology, virulence, and the interaction between host and pathogen. These vesicles allow bacteria to transmit enzyme and its contents as conserved form and also these involved in viability. Since they are represented as bacteria candidate, study of them can be help to learn more about bacteria and their interaction with the environment. Therefore, the isolation methods of vesicles are important. So, the aim of this study was to introduce a new method for isolation of Escherichia coli outer membrane vesicles.
The bacteria of Enterotoxigenic Escherichia coli were cultured under standard conditions. Supernatant was removed and then the tangential- trans flow filtration was used for concentrating vesicles, after that high speed centrifuges were used for obtaining the deposition. Isolated vesicles confirmed by transmission electron microscopy and molecular weight of the protein concentration was determined.
Vesicle morphology was confirmed by transmission electron microscopy and size of vesicles were determined between 50 to 100 nanometers. Electrophoretic pattern reflects the strong and weak bands in the region between 22-41 kDa and concentration of protein was determined 542 micrograms.
In the present study these results shows that the use of this method, in addition to provide same product, had positive benefits from time and economic perspective in compare to common procedure and It can also use to isolate the vesicles at the industrial level.