Electrofusion of Penicillium protoplasts after dielectrophoresis

The protoplast fusion of auxotrophic Penicillium mutants after dielectrophoretic cell contact and rectangular field pulses (4.2 kV/cm, 25 μs) was microscopically observed in a microchamber consisting of two vapor-plated chromium electrodes on a microslide (gap between the electrodes of about 150 μm). The conditions for protoplasting of Penicillium and for electrofusion are described. Isolation of auxotrophic mutants was realized after treatment of spores with UV light and X-rays. (author)