2086 Luria Agar with Ampicillin 50 µg/ml (Miller’s LB Agar), Merck

Luria Agar (Miller’s LB Agar) is a highly nutritious medium composed of Tryptone and Yeast Extract, which provide the essential nitrogen, vitamins, and minerals needed for robust bacterial growth. This version follows the Miller modification, containing 10.0 g/L of Sodium Chloride to maintain optimal osmotic balance for high-density E. coli cultures. The medium is pre-mixed with 50 µg/ml of Ampicillin, a beta-lactam antibiotic that inhibits cell wall synthesis. This ensures that only cells containing an ampicillin-resistance gene (such as the bla gene on common cloning plasmids) can proliferate.

Advantages

• Time-Saving Formulation: Eliminates the need to prepare, filter-sterilize, and manually add ampicillin to cooling agar.
• Consistent Selection Pressure: Pre-mixed components ensure a perfectly homogeneous distribution of the antibiotic throughout every batch.
• Reduced Risk of Contamination: Fewer handling steps during medium preparation lower the chance of introducing external contaminants.
• Optimized for Miller Strains: The 10 g/L salt concentration is preferred for many laboratory host strains to ensure plasmid stability and high growth rates.
• Clear Colony Morphology: Provides a transparent background that is ideal for colony counting and blue/white screening when supplemented with X-Gal/IPTG.

Technical specifications

Available packaging options