What is a Gram's stain technique?
1 Answer
A technique used to check the components of the cell wall of a bacterium species.
Explanation:
This method has been invented by a Danish bacteriologist named Hans Christian Gram and involves the staining of bacteria with special coloured compounds to understand their cell wall composition.
First, the cells are stained with a purple dye (Crystal Violet) for 30secs, after this step, the cells are flooded with Gram’s Iodine for another 30secs which forms a large dye complex with the purple dye and bind to the thick peptidoglycan layer of Gram positive bacteria.
Then, the stained cells are decolourised with alcohol which tightens the peptidoglycan layer by dehydrating it, thus preventing the purple-iodine dye complex from escaping the layer but decolourising the very thin peptidoglycan layer of the Gram negative bacteria. In the final step of the experiment,
Safranin is introduced for 30 more seconds staining it red and because of the light weight of the substance it does not affect the heavy colouring of the Gram positive cells, nevertheless colouring the Gram negative cells red.
