Evaluation of extracellular deoxyribonuclease activity in Pseudomonas.

Streitfeld, Murray M. (University of Miami, Coral Gables, Fla.), Edward M. Hoffmann, and Herbert M. Janklow. Evaluation of extracellular deoxyribonuclease activity in Pseudomonas. J. Bacteriol. 84:77-80. 1962.-Of 23 strains of P. aeruginosa isolated from pathological processes, 22 strains, representative of at least nine different somatic antigen types, were found to elaborate extracellular deoxyribonuclease. Qualitative determinations of enzyme elaboration were performed after the development of a convenient toluidine-blue assay plate procedure, dependent upon the metachromatic properties of the dye. This new procedure permits the determination of enzyme activity despite the presence, in the deoxyribonucleic acid-containing agar medium, of 2 to 5 ml/100 ml serum or plasma, or extracellular pyocyanin.