Advantages of staining how to be achieved if anyone please suggest or give me details with any bacterial if any.
Please 🙏 speak about it because I have interest on this matter.
Simple staining can do morphology of the cell structure but differential staining can differentiate pure district species G+ or G- bacteria visualisation.
Dear Dr. Saroj Kumar Khan
Yes, differential staining is useful for identifying between G+ or G- bacteria. Differential staining will help one to gather additional information about the bacteria one is working with. Differential stains use more than one stain, and the cells will have different appearance based on their chemical or structural properties. These stains include the gram stain, acid-fast stain, and endospore stain.
If we consider gram stain, it will give you information about the cell wall composition. Gram positive cells have thick layers of a peptidoglycan in their cell walls besides having teichoic acids. On the other hand, gram negative cells have an outer membrane that resembles the phospholipid bilayer of the cell membrane. The outer membrane contains lipopolysaccharides which are released as endotoxins when gram negative cells are killed by the immune system. So, the differences in the cell wall composition are reflected in the way the cells react with the stain used in the procedure using gram stain.
For instance, gram-positive organisms like Streptococcus species, Clostridium species and Listeria species will appear blue to purple under a gram stain, while gram-negative organisms such as Pseudomonas species, Neisseria gonorrheae and E. coli which have thin layers of peptidoglycan and high lipid (fatty acid) content causes them to appear red to pink under a gram stain.
There are also other special stains that you may use to identify specific external or internal structures that are not found in all bacterial species, such as a capsule stain or a flagella stain.
For example, some bacteria secrete a polysaccharide-rich structure external to the cell wall called a glycocalyx. If the glycocalyx is thin and loosely attached, it is called a slime layer. But if it is thick and tightly bound to the cell, it is called a capsule. To detect the capsule, you may use a negative staining procedure wherein the background (i.e., the slide) and the bacteria are stained, but the capsule is not stained. So, the capsule can be seen since it appears as a clear unstained zone around the bacterial cell.
You may also use silver stain to stain flagella which are long whip-like structures used for bacterial motility. Silver nitrate is applied to the bacteria along with a special mordant. The silver nitrate precipitates around the flagella thus causing thickening so that they can be observed under the light microscope.
Regards,
Malcolm Nobre
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