
Full text loading...
Two methods were developed to demonstrate a small fraction (10–4) of phage-sensitive cells in a phage-resistant population with a high degree of accuracy, using the plexiglass phage titration method (Horváth & Alföldi, 1954).
Phage-sensitivity was transferable by DNA isolated from Bacillus subtilis 168 m trp + phs (SPO-1 phage-sensitive) to the recipient strain of 168 m trp phr (SPO-1 phage-resistant) in transformation experiments. The number of 168 m trp + phs transformants was a function of the concentration of the transforming DNA. The trp + and phs characters are not linked. The competence curves for the number of 168 m trp + phr and 168 m trp + phs transformants were similar. The phenotypic lag was found to be 5 hr 30 min. The maximum frequency of 168 m trp + phs cells among the transformants was 2 to 5 %.