Gram Stain?

[Bioslave]

What is the purpose of using iodine for the gram stain? thanks.

[blcr11]

It's a mordant. It forms an insoluble complex with the primary Gram stain, crystal violet or methylene blue, and helps keep the dye stay put once it has bound to wherever it binds. It probably also adds something to the color, but its main function is to keep the dye fixed to the sample.

[Cat]

Iodine (mordant) forms complex with crystal violet that cannot be washed out from gram +ve cells because of thick layer of peptidoglycan.

[Bioslave]

thanks to both of you..

Bioslave