Investigation of membrane permeabilization on the electrotransformation of C. pasteurianum . Immediately prior to pulse delivery, cell-DNA suspensions were supplemented with 5, 10, or 15% ethanol (EtOH) or 1 or 2% butanol (BuOH). An untreated sample was included as a control. The time constant of each pulse is shown (ο). The sample treated with 2% butanol failed to grow during the allotted 16-hour recovery period following electroporation.