SOS induction by vacuum,desiccation and low-energy ion beam mock-irradiation in bacteria

In this work, we compared the SOS response induced by vacuum-drying, desiccation (wind-spray-drying) and low-energy ion beam mock-irradiation with that of mitomycin C, UV induction. The induction factor induced by vacuum-drying and low-energy ion beam mock-irradiation was relatively higher than that of desiccation in Sa194 and JC19008 strain, respectively. These findings revealed that the SOS response produced by low-energy ion beam mock-irradiation was mainly induced by the step of vacuum-drying, unlikely by the step of wind-spray-drying. The mutation frequencies of rifampicin resistance gene in AB1157 andlacI gene in W3110 increased significantly by vacuum treatment and low-energy ion beam mock-irradiation, but had no remarkable change by desiccation treatment. Meanwhile, the mutation frequency of rifampicin resistance gene in 1C400 strain was not significantly influenced by these treatments. These results implied that the SOS response played an important role in the mutations induced by vacuum treatment and low-energy ion beam mock-irradiation.