Isolation and preliminary characterization of bacteriophages for Bacillus subtilis.

Romig, W. R. (University of California, Los Angeles), and A. M. Brodetsky. Isolation and preliminary characterization of bacteriophages for Bacillus subtilis. J. Bacteriol. 82:135-141. 1961.-A simplified procedure for direct isolation of phages for Bacillus subtilis from soil was developed. Phage enrichment was accomplished by growing streptomycin-resistant B. subtilis in medium previously inoculated with the soil sample. Contaminating soil bacteria were eliminated by adding bactericidal quantities of streptomycin and the phages were isolated by conventional agar layer techniques. By this method 1 or more subtilis phages were isolated from 15 of 18 soil samples tested. Several of these phages were unusually sensitive to chloroform and all of them were relatively unstable when stored at refrigerator temperatures. Of 6 phages retained for study, 1 was temperate for B. subtilis, but attempts to obtain stably lysogenic bacteria following infection with this phage were unsuccessful. All 6 phages had identical host ranges and were able to lyse all strains of B. subtilis tested, as well as several related species of Bacillus.