What is gram staining?
The process of gram staining was first given by Danish bacteriologist Hans Christian Gram in 1884. On the basis of staining, he divided the bacteria into two types, the first is gram positive and the second is gram negative.
In his name, this method is called Gram's staining method and the stain is called Gram's stain.In this method, staining is done on the basis of the cell wall of the bacteria.
What is Principle of Gram staining ?
The bacteria cell wall is made by peptidoglycan material. The cell wall of gram positive bacteria is high in peptidoglycan, due to which the cell wall of gram positive bacteria is thick.
But due to the high amount of lipids in the cell wall of gram-negative bacteria, their cell wall is thin.
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Bacteria: Introduction, History, reproduction, cell structure , shape & size
What are the reagents and apparatus used in gram staining?
- Clean microscopic glass slide.
- Burnur - for heat fixing.
- Primary stain - Crystal violet.
- Iodine - Mordant.
- Ethanol/ Ethil alcohol - Decolorizer.
- Sefranine - Secondery Stain.
- Distilled water
- Microscope
What is the method of gram staining?
- The first step is to take a microscopic glass slide that is thoroughly sterilized with alcohol.
- Now we have to take sample first which we can take from curd or from other place or can also take cultured sample in laboratory.
- Now take the sample and make a thin layer in the clean glass slide with the help of a loop.
- Now with the help of a burner let's lightly heatfix the slide.
- After fixing the hit, now with the help of a dropper, take the primary stain crystal violet and put one to two drops on the smear.
- After adding the primary stain, the slide is washed with distilled water so that the smear is not left on the slide.
- After water wash, put one to two drops of iodine on the slide with the help of a dropper. And again water wash is done.
- Now after washing with water, put one to two drops of ethyl alcohol on the slide with the help of a dropper.
- After adding alcohol, now add secondary stand which is sefranine.
- After adding the second stain, the slide is again water bossed and after water washing, it is dried for 2 to 3 minutes and observed under the microscope.
What are the results of gram staining?
After gram staining, if we look at the slide in the microscope, if the bacteria appear purple in color, then it will be gram positive bacteria, if the bacteria appear pink or red in color.
What precautions should be taken while doing gram staining?
- All the equipment being used while using it should be sterilized.
- Thick layer of smear should not be made.
- Slides should not be heat fixed for long periods of time.
- While water washing the slides, a small amount of water should be used.
- All stains should be put on the slide in small amounts.
What is the importance of gram staining technique?
The Gram stain technique has been used to separate bacteria into two main groups on the basis of their cell wall composition for the successful use of antibiotics selected for the causative bacteria.
Some frequently asked questions -
Q1. Who introduced the Gram staining technique?
Ans. by Hans Christian Village Scientist.
Q2. Which stains are used in Gram staining technique?
Ans. Crystal Violet and Safranin.
Q3.Why is alcohol used in Gram staining technique?
Ans. Alcohol is used for decolorization.
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