What is Gram Stain?
Gram stain is a laboratory technique that differentiate bacterial cell on the basis of bacterial cell wall composition. It consists of four steps crystal violet (primary stain), Gram’s iodine (mordant), decolorizer (ethyl alcohol), and safranin (counter stain). These reagent impart color to the bacterial which differentiate between gram positive (purple) and gram negative (red).
Gram Staining – Principle, Procedure, Purpose and Examples
Gram stain is a technique to impart color to the bacterial cell to differentiate between gram-positive bacteria and gram-negative bacteria based on cell wall composition. Gram Staining is a laboratory procedure that consists of four reagents crystal violet (primary stain), iodine (mordant), decolorizer (ethyl alcohol), and safranin (counter stain) to stain the bacterial cell. Hans Christian Gram is a Danish bacteriologist who named this stain and developed this method in 1884.
The basic function of this technique is to differentiate between bacteria based on the chemical and physical properties of the cell walls. The difference in the cells can be identified by the cell wall as the gram-negative bacteria has a thin cell wall due to which the violet stain gets washed out with ethanol whereas the cell wall of gram-positive bacteria is thicker because of which violet stain stays out and give pink color to the bacteria.
Table of Content
- What is Gram Stain?
- Gram-Negative Bacteria
- Gram-Positive Bacteria
- Gram Staining Principle
- Gram Staining Requirements
- Gram Staining Procedure
- Purpose of Gram Staining
- Examples Gram Staining
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