Figure 3.

Superloser is rapidly lost in the presence of galactose. (a) Schematic of experimental setup. Briefly, three clones of BY4741 co-transformed with the indicated plasmid were cultured overnight in SC–Ura–Leu+2%dex. The following day these cultures were split and sub-cultured into SC complete +dextrose or SC complete +2%galactose/1%raffinose. Additionally, a portion of each culture was plated to YPD plates in two technical replicates. Each culture was then maintained in the indicated medium with each day a portion of each plated to YPD agar plates in two technical replicates. Finally, each YPD agar plate was replica plated to both SC–Ura and SC–Leu to track plasmid loss. (b) Example agar plates after 24 hr growth in SC complete +dextrose or SC complete +2%galactose/1%raffinose. Note the rapid loss of Ura⁺ colonies when in the presence of galactose (red outline, bottom). (c) Galactose induced loss of Superloser. The fraction of cells with the indicated plasmid is shown after removal of selection and induction (gray background to colored) under either dextrose (top row, blue) or galactose (bottom row, red). (d) Percent of cells with Superloser after induction with galactose or dextrose, Log10 scale (N = 6). Gray dots indicate growth in dextrose, red dots indicate growth in galactose.