ELECTROPERMEABILIZATION OF INTACT MAIZE CELLS INDUCES AN OXIDATIVE STRESS

By applying electric field pulses through cell suspensions, cell membr anes can be permeabilized transiently, giving free access to the cytos ol. Electropulsation is now routinely used in cell biology when introd ucing various molecules such as proteins and nucleic acids into the ce ll. But the molecular and cellular bases of cell electropermeabilizati on are still unclear. In the present study, we observed that electrope rmeabilization of intact black Mexican sweet (EMS) maize cells induces a generation of oxygen species (oxidative jump). Using the chemilumin escent probe lucigenin, we have shown that the electroinduced chemilum inescent response depends on the level of the stress factor as shown b y its dependence on the electric parameters (electric field intensity, duration, and number of pulses). While the electroinduced cell permea bilization has a short life, the oxidative jump that is triggered by t his electropermeabilization is a much longer-lived response. electroin duced loss in viability is linearly correlated to permeabilization. Ho wever, there is no correlation between the oxidative jump and the loss in viability. The modulation of oxygen species electroinduction by an tioxidant products (dimethylsulfoxide, sodium L-ascorbate, and glutath ione) does not lead to an increase in cell viability. Such results are different to those observed with mammalian cells and indicate that ev en if the same phenomenon is observed when pulsing mammalian or intact plant cells, the associated metabolic response is not the same.