Rapid and Efficient Escherichia coli Transformation Method

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Abstract

  Background & Objective: Transformation of plasmid DNA into bacterial competent cells is a key technique for molecular cloning. Transformation can be achieved using either chemical or physical methods, e.g., electroporation. The rate of success in these methods depends on experience and attention to method’s details. Therefore, the higher the efficiency and quality of a transformation method, the more the rate of success in that experience would be. The aim of the present study was to design a simple and rapid molecular transformation method, to achieve the efficiency without the need for special expensive apparatus.   Materials & Methods: In our improved method after preparation of bacterial cell’s pellet, it was resuspended in new Competent/Transformation Solution (CTS) the suspension was mixed with 1 µl (0.1ng) of plasmid DNA and incubated for 5-30 minutes at 4°C. Then 10 µl of 1 M glucose was added to it and cells were grown at 37°C with shaking for 1 hour. After incubation, the cells were spread on selective medium plates containing 100 mM CaCl2 by standard methods.   Results: This method does not necessary to heat shock and it is more efficient than classical transformation methods (107 transformants/µg). Conclusion: Our procedure represents a simple and convenient method for simultaneous Escherichia coli preparation and its transformation.

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