1970 Volume 16 Issue 1 Pages 61-79
Two methods for detecting DNase activity on agar plates were standardized on the basis of the complex formation of DNA with either Methyl Green or Acridine Orange. Bacterial colonies which excrete DNase could be easily recognized on these plates.
By these techniques, two strains of Bacillus subtilis which differed in the level of DNase activity were isolated. Nuclease activity of the two strains, SB168 and SB623, was compared under various cultural conditions.
Using polyacrylamide gel electrophoresis, culture media of SB623 were found to contain at least three components of DNase activity, in contrast to SB168 culture media, which showed only one peak, presumably corresponding to the middle component of the former. Properties of these activities were studied.
The nuclease-production character of SB623 could be transferred by DNA to SB168 or its derivative, giving rise to DNase-high strains. The nature of these transformants and the possible mechanisms of this transformation are discussed.