Electroporation at elevated temperatures substantially improves transformation efficiency of slow-growing mycobacteria

Abstract

The effects of electroporation temperature, biochemical pretreatment of cells and stage of culture on electroporation efficiency for slow-growing mycobacteria were investigated. The efficiency of transformation into Mycobucterium tuberculosis. Mycobarterium bovis and Mycobacterium intracellulure increased markedly with temperature. In contrast, the efficiency of transformation into Mycobacterium smegmatis, a fast-growing species, was higher at 0°C and decreased with temperature. While stage of culture had little effect, a further increase in efficiency of Z-l-fold was obtained following glycine or ethionamide pretreatment. Electroporation at 37°C has been chosen as a standard condition for slow-growing species as it usually resulted in a transformation efficiency several orders of magnitude higher than that obtained at 0°C.