Gram staining: Difference between revisions
Jump to navigation
Jump to search
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
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]] ) | ||
=== Method === | |||
*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. | ||
| Line 7: | Line 7: | ||
*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.<br> | ||
=== 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 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 [[Periplasm|periplasm]]. So it is stained by the counterstain of Safranin. | ||
Revision as of 14:05, 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.