Day 1 Inoculate 4 ml of lb medium containing 50 ug /ml ampicillin with a single bacterial colony containing the desired plasmid. Incubate at 37 C overnight with vigorous shaking Laboratory manual page 3120 Day 1 Inoculate 4 ml of LB medium containing 50 ug /ml ampicillin with a single bacterial colony containing the desired plasmid. Incubate at 37 ℃ overnight with vigorous shaking. Laboratory manual page 31