Endospore Stain Results

Purpose:  To differentiate between organisms that can produce endospores and those that cannot.  Also allows differentiation based on the position of the endospore in the cell

Principle:  Spores have a durable outer coating that is composed of the protein keratin.  This keratin coat resists staining so in order to stain a spore the primary stain, malchite green, must be heated to drive the stain into the spores.  Vegatative cells are then decolorized with water and 0.5% safranin is used to counterstain.  Thus endospores are stained green, while vegetative cells are stained red.

The stain to the right shows a bacterium capable of endospore production.
A.  Vegetative Cell
B.  Endospore

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