Gram Stainig

[deleted-94793]

Hello,

Does anyone know how to preform a gram stain? Where can I get the materials?

Thanks

[deleted-71536]

Hi John,

I have never performed a gram stain myself, though I understand how it works conceptually. Gram positive bacteria have thick cell walls, which soak up the purplish stain; gram negative bacteria have a thin cell wall underneath a membrane, and do not stain as readily.

Here are a few links with a descriptions and protocols for gram staining:
http://serc.carleton.edu/microbelife/re ... stain.html
http://www.uphs.upenn.edu/bugdrug/antib ... /Gram2.htm
http://www.life.umd.edu/classroom/bsci4 ... mStain.htm

There is even a YouTube video about it!
http://www.youtube.com/watch?v=OQ6C-gj_UHM

I found these links and more with a simple Google search for "gram staining." You can try looking for more of them yourself.

Let us know if you have more questions!

Heather

[deleted-80002]

Hi John,

The links that Heather gave you have really great explanations and protocols. I wanted to add a couple tips that I use for my own gram staining.

-The ethanol/acetone decolorizer will remove any marker that you put on your slide. When I mark on the glass slide where my sample is I use a china marker (grease pencil) to do the writing. These resist the decolorizer better.

-When doing the water rinses you don't want to wash right over where your sample is. The water pressure can wash off some of your sample. I usually place the back side or edge of the glass slide under the stream of water. That way the water is moving much slower as it reaches you sample.

-Make sure to use fresh bacteria. As a bacterial culture gets old the cell walls get thicker. This can cause a false positive (gram negative bacteria may appear gram positive).

I hope that helps.
Kierstyn

[deleted-94793]

Thank you very much