A few theories Of Gram Staining are as under, which is more correct or less correct can anyone explain?
1. Cell wall theory: Cell walls of Gram-positive bacteria are 40 times thicker than those of Gram-negative cells, hence they are thought to help retain the dye-iodine complex.
2. Lipid Content Theory: The cell envelope of Gram-negative bacteria contains an additional membrane (outer membrane). hence containing more lipids than Gram-positive bacteria. Acetone or alcohol dissolves the lipid thus forming large pores in Gram-negative bacteria through which the dye-iodine complex leaks out.
3. Alcohol/acetone dehydrates Gram-positive bacteria shrinking the cell wall and closing the pores.
4. Magnesium Ribonuclease Theory: A compound of magnesium ribonuclease and basic protein concentrated at the cell membrane helps Gram-positive bacteria retain the primary dye. Gram-negative bacteria do not possess this substance.
5. Cytoplasmic pH Theory: The cytoplasm of Gram-positive bacteria are said to be more acidic than those of Gram-negative ones. Hence the dye is said to bind with more affinity to Gram-positive cells.
Dr Singh , i think , you have already so imressively explained. ..
- Badges
- Science method