I should have the dried cultures ready in a few days. Unfortunately, I do not have this stock dried.
You can prepare the triply marked stock Strep 2, Catho 2, and Eryth 2 from the sensitive Rd by a single days effort. Simply
plate the cells at low dilution with all time antibiotics after treatment with the multiply marked T.P. and suitable time
for expression. The frequency of S2C2E2 should be the frequency expected for double transformation since S and C are linked.
The frequency of doubles is the product of the single frequencies unless the cells are transforming at low frequencies in
which case a competency