Transformation of bacterial cells Transformation does not naturally occur in most strains of bacteria, including E. coli E coli and other bacteria can be forced to take up DNA by special chemical and temperature treatments DNA can also be put into bacterial cells by first treating the cells with a brief high voltage pulse (electroporation) This causes a temporary production of pores in the cell membrane, allowing the dNa to pass into the cell.Transformation of bacterial cells • Transformation does not naturally occur in most strains of bacteria, including E. coli. • E. coli and other bacteria can be forced to take up DNA by special chemical and temperature treatments • DNA can also be put into bacterial cells by first treating the cells with a brief high voltage pulse (electroporation). This causes a temporary production of pores in the cell membrane, allowing the DNA to pass into the cell