Abstract
The effect of salt on phages and their host bacteria was investigated using phage J1 of Lactobacillus casei S1 and phages M2 and SPO1 of Bacillus subtilis YS11. With phage J1 at 37°C, salt did not affect the infectivity of the phage, but prevented its adsorption. Salt completely inhibited the growth of phage at 1.0 M. With phages M2 and SPO1, salt did not affect the infectivity of phages. It prevented the adsorption of phage SPO1, but not of phage M2. Salt completely inhibited the growth of phages at 1.2-1.3 M. At 40°C in the absence of salt, the growth of phage J1 was completely inhibited, whereas the growth of the host bacteria was the same as at 37°C. With phages M2 and SPO1 at 45-46°C, growth was completely inhibited, whereas the growth of the host bacteria was more rapid than at 37°C. These findings suggest the possibility of phage control by means of elevating incubation temperature. At 39°C, lower concentrations of salt inhibited the growth of phage J1. This result suggests the possible use of salt for the control of phage. With phages M2 and SPO1, this is not true at 44-45°C.
