Large-scale production of yeast hybrids by electrofusion

Abstract Large-scale production of electrically fused yeast protoplasts from Saccharomyces cerevisiae AH 22[pADH 040-2] and S. cerevisiae AH215 was achieved by the use of the so-called helical fusion chamber. Both strains were of the same mating type a and carried the following auxotrophic markers: his4 in the case of AH22 and leu2, his3 in the case of AH215.
AH22 also is a carrier of the plasmid pADH 040-2. This plasmid confers the leu2 gene of yeast and the β-lactamase gene from Escherichia coli , and this feature enables quick detection of plasmid-positive cells.
After dielectrophoresis (275 V/cm, 800 kHz) fusion was induced by two field pulses (10 kV/cm, 10 μs duration) applied at an interval of 0.5 s. 50 to 60 hybrids per run were isolated after regeneration on selection medium.