LB Agar Plates (Miller formulation) with 100 µg/mL Ampicillin are for growth and maintenance of E. coli containing recombinant plasmids. LB Miller media is nutritionally rich, allowing for rapid growth.
Ampicillin is used to select for mutated or transformed cells that are ampicillin resistant (Amp or AmpR) [i.e., carry the β-lactamase (bla) gene]. Typically, low-copy-number plasmids require less ampicillin than high-copy-number plasmids. 100 µg/mL Ampicillin is the most commonly used concentration.
If satellite colonies form due to extracellular secretion of lactamase, replace ampicillin with carbenicillin, a stable, semi-synthetic ampicillin analog.
Typically, 100 mm round plates are for growth/selection, 150 mm round plates are for screening, rectangular plates can be used with automated systems, and grids can be helpful when counting colonies.
Contains 1.0% (10 g/L) tryptone, 0.5% (5 g/L) yeast extract, 1.0% (10 g/L) sodium chloride, 100 µg/mL ampicillin, and 1.5% agar.