Deoxyribonuclease and competence factor activities of transformable and nontransformable group H streptococci

Abstract

Sixteen strains of group H streptococci were tested for their capacity to produce a nuclease which degraded transforming deoxyribonucleic acid (DNA), for the ability to produce the competence protein (CF), and for transformability. Six strains produced CF and were transformable upon exposure to DNA. Two strains did not synthesize CF but could be converted to transformability with CF of other strains. All transformable strains exhibited extracellular deoxyribonuclease activities of varying degrees. There was, however, no relationship between the efficiency of transformation of a particular strain and its nuclease activity. Of the eight nontransformable strains, one produced CF but no nuclease. Another strain produced some extracellular deoxyribonuclease but no CF. The remaining strains lacked both functions. The nuclease and the CF activities appeared to be expressed by different proteins.