The Effects of Streptomycin, Desiccation, and UV Radiation on Ice Nucleation by Pseudomonas viridiflava.

Streptomycin (100 micrograms per milliliter), desiccation (over CaSO(4)), and ultraviolet radiation (4500 microwatts per square centimeter at 254 nanometers for 15 minutes) reduced ice nucleation activity by Pseudomonas viridiflava strain W-1 as determined by freezing drops of the bacterial suspensions. Highest residual ice nucleation activity by dead cells was obtained by desiccation, although no freezing above -3.5 degrees C was detected. The rate and extent of loss of ice nucleation activity following streptomycin and ultraviolet treatment was affected by preconditioning temperature. At 21 degrees C and above, loss of activity by dead cells was rapid and irreversible.