The effect of magnesium of transfection and transformation in Bacillus subtilis

The influence of Mg2+ on phage SPP1 DNA-mediated transfection as compared with chromosomal transformation was studied. A differential influence of this cation in both processes was detectable by analyzing the competence development and the kinetics of appearance of transformants and transfectants. Binding and uptake of DNA and release of acid-soluble products by competent cells in high- and low-Mg2+ media was measured for 3H-labelled SPP1 and 3H-labelled Bacillus subtilis DNAs. Phage SPP1 DNA was shown to be subjected to endonucleolytic cleavage after exposure to competent cells.