Transformation

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Transformation

• Playing with Bacterial Plasmids (DNA)

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What is it?

• Background
• 1928-Dr. Frederick Griffith studied two forms of
  S. pneumoniae
• Pathogenic strain (smooth)- polysaccharide
  coating
• Non-pathogenic (rough)
• Injected into mice
• Rough Mice lived
• Smooth Mice died
• KILLED smooth Mice lived
• A mix of killed smooth rough, what should
  happen?

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How could this be?

• DNA had to have been exchanged between the two
  types of bacteria
• Transformation uptake and expression of free DNA
  by cells
• Bacteria do this regularly
• Have surface proteins that recognize DNA and
  transport it into the cell
• If enough like the cells original, it is used
  (Recombination)
• If not, it is destroyed

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We are going to do this

• We will clone a plasmid that contains two special
  genes into E. coli
• One that makes jellyfish glow (pGLOW)
• One that makes bacteria resistant to antibiotics
• Ampicillin