A09 Growing Bacteria in Liquid Media

Purpose

To demonstrate techniques used in preparing cultures from plates and from stock sources.

Procedure

  1. Use gloves to avoid adding adventitious organisms to the broth. Identify the colony or source of bacteria. Use a sterile toothpick to touch the colony.
  2. Open a culture tube containing broth. Flame the tube. Drop the toothpick into the tube. Touch only the tip of the sterile toothpick with the gloves. When the bacteria have been transformed with plasmids, the growth medium will contain an antibiotic. Bacteria from the environment are unlikely to survive in the presence of the antibiotic.
  3. An alternative procedure involves use of an inoculating loop. Flame a loop. Open the source. Insert the loop into the source. Remove and close the source. Flame the culture tube. Insert the loop and swirl. Flame the culture tube and cover.
  4. Bacteria often are grown overnight. Preparation details vary according to specific experiment.
  5. Bacteria are used for small scale plasmid isolation (A-27), large scale plasmid isolation (B-31), or transformation (A-22).

References