The mechanism of competence in the transformation of streptococci of serological group H

Summary The production of a special competence factor (cpf) by the recipient cells is one of the key-elements of the complex mechanims of competence in transformation. The role of cpf and its interrelation with the other factors involved in competence remain obscure. The evidence regarding the genetic background of competence is also very scarce.The cpf production ability was demonstrated to be a genetic unit which could be transferred in transformation. The cpf marker was transformed in a heterospecific reaction, in which the S. challis (cpf ⁺) strain was the DNA donor, and S. wicky (cpf ^–) its recipient.As a result of the incorporation of this marker, S. wicky cells acquired the stable cpf production ability and, consequently, the transformation ability in a yield equal to that shown by the donor cells. DNA isolated from the S. wicky (cpf ⁺) transformants could be applied, in turn, as a donor of the cpf marker. The experiments were performed by a semiquantitative technique and the yield of the transfer of the cpf marker amounted to about 1%.