Influence of temperature-induced competence in the genetic transformation of Bacillus subtilis

Competence of Bacillus subtilis can be induced or repressed by decreasing or raising the temperature of incubation from 42 degrees C to 37 degrees C or vice-versa. Concomitantly with changes in transformability of the cultures, changes in the cell ability to bind 3H-transforming DNA and to degrade the donor DNA was discovered. These alterations reflect changes in the processing of donor DNA rather than at the level of integration of the transforming DNA, since phage SPP1 DNA transfection was affected to the same extent as transformation. Induction of competence development by temperature shift from 42 degrees C to 37 degrees C requires continuous synthesis of protein(s) involved in the binding of donor DNA to the competent cells, whereas the nucleolytic activity related to DNA entry into the cells is already synthesized at the moment of the induction of competence.