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Plating of E. coli cells onto an LB-agar plate.


  • LB-agar plate (w/ appropriate antibiotic, if required)
  • sterilized, wooden stick or sterile Pasteur pipette
  • E. coli cell sample, either from another plate, frozen stock, or cell culture


  • From plate or frozen stock:
  1. Under sterile conditions, pick a single colony using a sterile stick (if frozen stock, dip the tip of the stick into the stock) and drag the cells along the surface of the plate.
  2. Using another stick, drag through the line of (now-deposited cells) to an untouched portion of the plate surface.
  3. Repeat the previous step on the newly formed line until there are 4-5 total lines on the plate.
  4. Incubate overnight 37 °C (or special temperature).
  • From cell culture:
  1. Dilute the cell sample to a density of ~104 cells / mL (OD600 ~ 10-5).
  2. Under sterile conditions, pipette 30 μL cells onto the LB-agar plate. Spread until dry using the sterile Pasteur pipette. (This will provide ~300 colonies.)
  3. Incubate overnight 37 °C (or special temperature).


Please feel free to post comments, questions, or improvements to this protocol. Happy to have your input!

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  • SC 17:27, 25 June 2012 (EDT):

or instead, discuss this protocol.