Transfection of Streptococcus pneumoniae with bacteriophage DNA

Abstract

It was possible to transfect Streptococcus pneumoniae with DNA obtained from a newly isolated bacteriophage, diplophage-4 (Dp-4). Optimal frequency of transfection (0.9%) required the use of a nuclease-defective mutant; with wild-type bacteria, the transfection frequency was about 100-fold lower. Transfection requires physiological conditions that appear to be similar to the competent state needed for genetic transformation (A. Tomasz, J. Bacteriol. 91:1050--1061, 1966).

Protease-sensitive transfection of Streptococcus pneumoniae with bacteriophage Cp-1 DNA

“…The results shown in Table 1 demonstrate that the infectivity of Cp-1 DNA was remarkably reduced when the DNA was treated with proteolytic enzymes. In contrast, Dp-4 DNA was not affected by the treatment with proteases as previously reported (31). The fact that the inactivation could be prevented by the specific protease inhibitor indicated that we were analyzing an effect which must be attributed to specific protease activity and not, for example, to contaminating nucleases.…”

“…Transfection with mature Dp-4 (30,31) and w3 phage DNAs as well as with the replicating form of w3 DNA has been reported in Streptococcus pneumoniae (11,26). In addition, a substantial t In memoriam of our friend Domingo Rodriguez.…”

“…Phages. Bacteriophages Cp-1 and Dp-4 and details of the preparation and purification of these phages have on September 29, 2020 by guest http://jvi.asm.org/ Downloaded from been described elsewhere (29,31) except that tryptic soy broth was used instead of K-CAT medium for the preparation of Cp-1.…”

“…Dialysis bags were treated as previously described (8) to reduce the sticking of the material to the bag. Protease-treated Cp-1 DNA and Dp-4 DNA were isolated as described before (29,31).…”

Transfection of protoplasts of Streptococcus lactis subsp. diacetylactis

“…Although there is substantial knowledge on the transfection of several streptococcal species [1][2][3], the infection of lactic streptococci by purified bacteriophage DNA has not yet been reported.…”