Blue Juice

Colonies that express functional LacZ will appear blue.

• 0.55 g X-gal
  
• 0.06 g IPTG
  
• add dimethylformamide to 10 ml
  
  • note that dimethylformamide will very rapidly degrade polyethylene and polycarbonate ("clear" plastics). use glass and/or polypropylene
    

store at -20C

Spread 100 μl per 10 cm agar bacterial plate for visualization of LacZ alpha-complementation.

alternatively, buy it premade from Sigma for extra money

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Comments

• It is often helpful to place plates at 4C for several hours after colonies have grown to enhance visualization of the blue color.