Study On High Voltage Electric Field Induced Strain Of Escherichia Coli K12

In this study, the wild-type Escherichia coli (E. coli) K12 W3110 was the research object, The bacteria were treated by the high-voltage electrostatic field (HVEF) and high-voltage variable frequency electric field (HVFEF), also with two control groups setting up, respectively:spontaneous group (CK1) and drying control group (CK2). By examining cell survival rate, mutation rate and morphological damage of the cell, to study the damage effect of E. coli by high voltage electrostatic field effect; The mutant were screened from the treatment conditions with significant mutation rate (HVEF:4kV/cm* 2min; HVFEF:4kHz* 4kV/cm* 6min) (HVEF: 4kV/cm* 2 min; HVFEF:4kHz* 4kV/cm* 6min) and draw mutation spectrum of E. coli lacI gene, research mechanism of lacI gene mutations induced by high voltage electric field.The experimental results show that:(1) HVEF treatment:With electron microscope, it was found that the cell membrane was damaged and the cell contents were overflow, which caused by the effect of HVEF, showed that HVEF can effectively destroy the cell membrane structure; By examine the changes of nucleic acid and protein content relative of the bacteria under the same field and different time, we found that the change of the above two parameters were oscillatory, showed that the HVEF could regulate the permeability of the cell membrane, and E. coli itself may have the function of damage repair. Under the dose of 4 kV/cm* 2 min, the mutation rate was the highest, shows (13.73±1.99)* 10-6。(2) HVFEF treatment:Under the conditions of 4kHz* 4kV/cm* 6min, the mutation rate was the highest, shows (17.96 ± 1.43)* 10-6, were 14.97 times of spontaneous mutation rate (1.20* 10-6) and 7.16 times of drying control group (2.51 * 10-6). The result illustrate that HVFEF was a mutagenic agent of low damage but significant mutagenic effect.The mutation spectrums of lacI gene were drawn respectively and compared with mutation spectrums of lacI gene mutated by other factors. The results showed that HVEF and HVFEF maybe induce the SOS reaction of E. coli to produce mutations; and the indirect effects of HVEF and HVFEF may also cause the gene mutation.