Lidstrom:E. coli media comparison: Difference between revisions

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* LB contains a milk digest (tryptone) and hence can induce cultures with lac based promoters when they near saturation.   
* LB contains a milk digest (tryptone) and hence can induce cultures with lac based promoters when they near saturation.   
** "LB ... contains enzymatic digests of the milk protein casein (e.g., tryptone or N-Z-amine) and yeast extract. Since milk is rich in lactose, an inducer of the T7 expression system, variable amounts of residual lactose may be present in different lots of these enzymatic digests. These small amounts of lactose do not promote appreciable induction during log-phase growth, but even minute amounts are sufficient to cause induction on approach to saturation, particularly at lower rates of aeration, which allow induction at lower lactose concentration and promote higher levels of induction." -- [http://www.ncbi.nlm.nih.gov/pubmed/24203322 Sturdier 2014]
** "LB ... contains enzymatic digests of the milk protein casein (e.g., tryptone or N-Z-amine) and yeast extract. Since milk is rich in lactose, an inducer of the T7 expression system, variable amounts of residual lactose may be present in different lots of these enzymatic digests. These small amounts of lactose do not promote appreciable induction during log-phase growth, but even minute amounts are sufficient to cause induction on approach to saturation, particularly at lower rates of aeration, which allow induction at lower lactose concentration and promote higher levels of induction." -- [http://www.ncbi.nlm.nih.gov/pubmed/24203322 Sturdier 2014]
 
* [http://schaechter.asmblog.org/schaechter/2009/11/the-limitations-of-lb-medium.html This article] criticizes LB for its low magnesium and carbohydrate content, and is a must-read for understanding rich media options.


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Revision as of 07:47, 14 April 2015

LB

  • A default rich media for E. coli
  • LB contains a milk digest (tryptone) and hence can induce cultures with lac based promoters when they near saturation.
    • "LB ... contains enzymatic digests of the milk protein casein (e.g., tryptone or N-Z-amine) and yeast extract. Since milk is rich in lactose, an inducer of the T7 expression system, variable amounts of residual lactose may be present in different lots of these enzymatic digests. These small amounts of lactose do not promote appreciable induction during log-phase growth, but even minute amounts are sufficient to cause induction on approach to saturation, particularly at lower rates of aeration, which allow induction at lower lactose concentration and promote higher levels of induction." -- Sturdier 2014
  • This article criticizes LB for its low magnesium and carbohydrate content, and is a must-read for understanding rich media options.

NB

  • Stands for "nutrient broth"
  • Lower in salt (NaCl) than LB

Autoinduction (Sturdier)

  • It is called auto-induction because it causes lac-based expression as cultures near saturation. No addition of IPTG is required.
  • See: Lidstrom:Autoinduction_Media

M9

  • Minimal (no yeast extract or milk digest)