Transformation into Yeasts and Fungi by Electroporation

We measured gene transfer efficiency using the ELEPO21 in yeast. Competent cells were prepared as usual from budding yeast S. cerevisiae. The competent cells were mixed with pAS2 DNA, and a 20μl aliquot (containing 108-1010 cells and 50 ng DNA in 1M sorbitol solution) was transferred to the 1 mm gap electrode cuvette (EC-001, Nepa Gene). The cuvette was set in the chamber connected to the ELEPO21, and delivered 3-step pulses as described below. All steps were done on ice. After electroporation, the cells were plated on selective agarose medium devoid of nutrients, and the colonies formed were counted. Transformation efficiency was expessed as a number of colonieis per μg plasmid DNA.

ELEPO21: pulsing conditions
Poring Pulse（voltage: 500 V, pulse length：1.5 msec, pulse interval：50 ms, number of pulses：5, polarity：+）
Transfer Pulse（voltage: 50 V, pulse length：50 msec, pulse interval：50 ms, number of pulses：5, polarity：+/-）
To evaluate the above results, we measured gene transfer efficiencies using a conventional electroporator (ECM630, BTX) that deliver a single exponential pulse as described below.

ECM630: pulsing conditions
Single pulse (voltage：750 V, resistance：200Ω, capacitance：25μF, number of pulse：1)

Fig 1: ELEPO21 Result                 Fig 2: ECM630結果
　　

Fig 3:

The above cell suspensions (sample resistance value：12.36 KΩ) were used for electroporation.

The tranformation efficiency obtained by the ELEPO21 was approximately 6 times higher than that by the ECM630 electroporator (Fig. 1-3).
*The values are averages of repeated experiments.
*The optimum pulsing conditions were used for ELEPO21 and ECM630.
*cfu: colony forming unit.