Development of strategy for competent cell preparation and high efficiency plasmid transformation using different methods

Abstract

Current cloning technologies based on site-specific recombination are efficient, simple to use, and flexible. With the recent availability of complete genomic sequences of many organisms and plants, high-throughput and cost-efficient systems for gene cloning and functional analysis are in great demand. This study compares two different methods of preparation of competent cells using two strains of E. coli DH5α and HB101. From results the most efficient strain was found DH5α for cloning as it supports blue white screening utilizing galactosidase activity. The concentration of calcium chloride is another important factor; various concentrations of CaCl₂ were tried. Optimum concentration was found to be 75 mM. However PEG also has great influence on transformation efficiency, use of 40% PEG gave the best transformation efficiency. A convenient and rapid method for the genetic transformation of E. coli with appropriate plasmid is proposed which can be utilised for high efficiency transformation in normal laboratory conditions.