Negative Stain

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Negative Stain

• Experiment 11

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Negative Stain

• This is a background stain so slide is colored
  black, your specimen will be clear
• The stain is negatively charged, acidic dyewill
  not enter the cell or bind to it
• Bacteria are (-) Nigrosine dye (-)
• This is the ONLY stain you will perform WITHOUT a
  smeardo not heat fix
•  

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Negative Stain

• Information you will obtain can be used to verify
  last weeks results
• Morphologyshape and arrangement
• Problems
• To much stainthick light wont pass through,
  reverse is true if not enough
• Check the stain bottlesif you can see thru do
  not use

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Procedure

• 1. Add 1 drop of nigrosine to one end of the
  slide
• 2. Mix a loop full of cells with the dye
  (Sterilize your loopdont touch hot)
• 3. Use 2nd slide, spread the dye across the
  surface of 1st slide
• 4. Air dry and observe (do not heat fix, do not
  wave or blow on slide)

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• While your slide is air-drying check the contents
  of your drawers you must have the following
  before you leave so do it now while you are
  waiting for slide to dry
• 4 slants
• 1st Unknown d
• 2nd Isolate (yours from Petri)
• 3rd Fresh for Gram Stain
• 4th Fresh for Gram Stain

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Fill In