Gram staining: Difference between revisions
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Gram staining refers to a experimental method of placing bacteria into two sub-groups.( [[Gram positive]] and [[Gram negative]] ) | Gram staining refers to a experimental method of placing bacteria into two sub-groups.( [[Gram positive]] and [[Gram negative]] ) | ||
<u>'''Method'''</u> | <u>'''Method'''</u> | ||
*Heat fix the bacterial sample to the slide, so that is is not washed away when applying further chemicals. | *Heat fix the bacterial sample to the slide, so that is is not washed away when applying further chemicals. | ||
*Apply the Primary stain, [[Crystal Violet ]]for one minute then rinse with water. | *Apply the Primary stain, [[Crystal Violet]] for one minute then rinse with water. | ||
*Cover slide with Gram's Iodine for a further minute. | *Cover slide with Gram's Iodine for a further minute. | ||
*Apply acetone to decolourise for no more than 5 seconds and wash with water. | *Apply acetone to decolourise for no more than 5 seconds and wash with water. | ||
*Apply [[Safranin]] as a counterstain for 2 minutes and was again with water. | *Apply [[Safranin]] as a counterstain for 2 minutes and was again with water. | ||
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<u>'''Results'''</u> | |||
A [[Gram positive]] bacteria should give a purple stain. This is because the thick layer of [[Peptidoglycan]] retains the purple crystal violet stain. | |||
A [[Gram negative]] bacteria should give a pink stain. This is becaue it does not retain the crystal violet because the peptidoglycan layer is in the [[Periplasm|periplasm]]. So it is stained by the counterstain of Safranin. | |||
A [[Gram negative]] bacteria should give a pink stain. This is becaue it does not retain the crystal violet because the peptidoglycan layer is in the [[ | |||
Revision as of 12:49, 8 November 2011
Gram staining refers to a experimental method of placing bacteria into two sub-groups.( Gram positive and Gram negative )
Method
- Heat fix the bacterial sample to the slide, so that is is not washed away when applying further chemicals.
- Apply the Primary stain, Crystal Violet for one minute then rinse with water.
- Cover slide with Gram's Iodine for a further minute.
- Apply acetone to decolourise for no more than 5 seconds and wash with water.
- Apply Safranin as a counterstain for 2 minutes and was again with water.
Results
A Gram positive bacteria should give a purple stain. This is because the thick layer of Peptidoglycan retains the purple crystal violet stain.
A Gram negative bacteria should give a pink stain. This is becaue it does not retain the crystal violet because the peptidoglycan layer is in the periplasm. So it is stained by the counterstain of Safranin.