Non-invasive, electro-orientation-based viability assay using optically transparent electrodes for individual fission yeast cells.

A non-invasive assay of cylindrical yeast cell viability based on electro-orientation (EO) in an alternating electric field was developed, in which cell viability can be determined by each cell's EO direction without the need for reagents. A cell suspension of a few microliters was sandwiched between a pair of optically transparent indium-tin-oxide (ITO) plate electrodes. Observation under a light microscope enabled easy identification of EO based on cell shape, e.

Gene transfer and protein release of fission yeast by application of a high voltage electric pulse.

A high voltage electric pulse can be applied to induce the uptake of DNA into cells and the release of protein from cells. In transformation procedures, electroporation is widely used since the technique is simple, rapid, reproducible, and highly efficient. In extraction of protein, on the other hand, electroextraction has many advantages over other conventional extractions.

Electrically induced protein release from Schizosaccharomyces pombe cells in a hyperosmotic condition during and following a high electropulsation.

A high-electric-field application of fission yeast cells under hyperosmotic conditions improved the electro-induced release of protein and cytoplasmic enzymes. A cell suspension was pulsed at 12.5 kV/cm for 10 ms in a batch system and immediately postincubated at 30 degrees C.

A rapid and simple procedure for high-efficiency lithium acetate transformation of cryopreserved Schizosaccharomyces pombe cells.

A rapid, simple, convenient, and highly efficient transformation of the fission yeast Schizosaccharomyces pombe has been developed. Freezing fission yeast cells in glycerol, a permeating cryoprotectant, with lithium acetate improved remarkably the transformation efficiency by one to two orders of magnitude. The optimum concentration of glycerol was found to be 30%, which is higher than that (10-15%) in the conventional cryopreservation of yeast cells.

High osmotic stress improves electro-transformation efficiency of fission yeast.

A preincubation of fission yeast cells with hyperosmotic solution improved the electro-transformation efficiency. The efficiency increased approximately five-fold when the cells were preincubated with 2.0 M sorbitol and 1.

High-efficiency electroporation by freezing intact yeast cells with addition of calcium.

We developed a novel freezing method to generate competent cells of Schizosaccharomyces pombe and Saccharomyces cerevisiae prior to electroporation. Freezing the intact cells in sorbitol with the addition of calcium at -80 degrees C allowed us to improve the transformation efficiency after freezing and thawing. The optimum concentration of CaCl(2) was found to be 5-10 mM.