BY4742 Yeast Competent Cells

YCC-003

BY4742 Yeast Competent Cells

100 μl*50

BY4742 is derived from the original strain S288C of Saccharomyces cerevisiae, which is a commonly used strain in the laboratory. The pYES2 plasmid can be directly transformed into BY4742 cells by PEG/LiAc. The screening marker for plasmid pYES2 is URA, and it can be screened by an SD-URA plate.

Transformation efficiency >10⁴ cfu/ug DNA as assayed by pYES2 plasmid.

1). Take a sterile 1.5 ml EP tube, sequentially add 1-3 μg of pre-cooled target plasmid, 10 μl of Carrier DNA (95-100 ℃ for 5 min in a rapid ice bath, repeat once), and 100 μl of competent cells melted on ice, 500 μl of PEG/LiAc, and gently turn and mix 6-8 times.
2). 30 ℃ water bath for 30 min, every 10 min gently turn over and mix 6-8 times.
3). Add 20 μl of dimethyl sulfoxide to each branch (used to improve the conversion efficiency, can not be done).
4). 42 ℃ water bath for 15 min, every 5 min gently turn over and mix 6-8 times.
5).12,000 rpm instantaneous centrifugation and discard the supernatant, add 1 ml of YPD Plus to each cartridge, and resuscitate at 30℃ for 1 h (used to improve the transformation efficiency, can not be done).
6).12,000 rpm instantaneous centrifugation and discard the supernatant, resuspend with 100 μl of 0.9% NaCl, coat the plate, and incubate at 30℃ for 48-96 hours.

1). Competent cells are best melted on ice, PEG solution will precipitate at low temperatures, please dissolve completely at room temperature before use.
2). Transforming a high concentration of plasmid can reduce the amount of bacteria used for plate coating.
3). When transforming 2-3 plasmids at the same time, the amount of plasmid can be increased.
4). The yeast strain is sensitive to high temperatures, and the optimal growth temperature is 27-30℃. Above 31°C, the growth rate and transformation efficiency decreased exponentially.
5). Colonies turning pink is not contamination and is a common phenomenon in yeast cell growth. When the cells are cultured in plates for a few days, the Adenine on the plates is consumed by the yeast and the yeast attempts to synthesize Adenine for utilization through its metabolic pathway. However, in some strains, the ADE2 gene is disrupted and the Adenine synthesis pathway is blocked, and because their ADE4, 5, 6, 7, and 8 genes are normal, the intermediate product AIR accumulates in the cells and causes the colonies to turn pink.
6). Yeast growth in the defective medium was slower than in the YPDA medium, and the more defective components in the medium, the slower the growth. Take the transformation coated plate for example, coated YPDA plate at 29 ℃ culture 48h visible diameter of 1 mm clones; coated SD single-deficient plate 29 ℃ culture 48- 60h visible diameter of 1 mm clones; coated SD double-deficient plate 29 ℃ culture 60- 80h visible diameter of 1 mm clones; coated SD triple-deficient or quadruple-deficient plate 29 ℃ culture 80-90h visible diameter of 1 mm clones.

5 μg/μl, 100 μl

5 ml

Competent cells are transported on dry ice and stored at -80°C. Carrier DNA needs to be stored at -20°C. PEG/LiAc needs to be stored at 4°C.

6 months