Influences of pulsed electric fields on the gene expression of pathogenic bacteria

Abstract

The application area of pulsed power technology is expanding into biotechnology and green technology. In particular, biological and medical field as sterilization with pulsed electric fields or discharges and electroporation have been studied actively in recent years. It is clear that the pulse electric fields bring some sort of influences to organism. But for now, it is not sufficiently clear what influence appears and how mechanism works on organisms by the pulsed electric fields. To clarify them will prominently develop the biological application area of pulsed power technology. The influences of pulsed electric fields on gene expression of pathogenic bacteria have been studied. Vibrio parahaemolyticus as pathogenic bacteria was selected as an experimental object. The solution whose bacterial density is 109 /ml and volume is 2 ml is applied with 100 or 1000 pulsed electric fields. The expression level of RNAs as VP1680, VP1699, TDH, and RNA16S is analyzed by method of PCR. To apply the pulsed electric fields, a system, consisting of the Blumlein-type pulse forming network (B-PFN) and electrodes chamber, was used. The B-PFN outputs pulses with width of 100 ns in the case of 5 L-C stages. When the separation of the electrodes of chamber was 5 mm, the peak electric fields applied to the solution was evaluated to be approximately from 4 to 14 kV/cm on some experimental conditions. The gene expression of VP1680 and VP1699 increased by comparison with negative controls. On the other hand, the expression of TDH fluctuated. These results would suggest a probability of selective control on gene expression by pulsed electric fields and would develop new application such as functional foods.