THYMINELESS INDUCTION OF BACTERIOPHAGE IN BACILLUS MEGATERIUM.

Maisch, W. F. (University of Illinois, Urbana), and J. T. Wachsman. Thymineless induction of bacteriophage in Bacillus megaterium. J. Bacteriol. 88:1388-1393. 1964.-Strain KM:T(-)(L) of Bacillus megaterium was obtained by lysogenizing a previously characterized thymine auxotroph of strain KM (KM:T(-)) with a phage suspension from B. megaterium 899a. When strain KM:T(-)(L) is deprived of thymidine in an otherwise sufficient medium, both thymineless death and phage induction occur. The presence of thymidine is required, however, for phage development. When cells are starved for 2 hr, intracellular phage and free phage may be detected approximately 30 and 40 min, respectively, after thymidine addition. Maximal free phage titers were found to vary between 3 x 10(8) and 5 x 10(9) per ml. This represents as much as a 50,000-fold increase in free phage titer over that found during thymidine starvation, and up to a 1,000-fold increase over that found during normal exponential growth.