#negative staining

Negative staining: Principle, Procedure and Result

Negative staining procedure is used to study cell shape, cell breakage, capsule, surface inclusions and spores beside poly-beta-hydroxybutyrate granules. 

For bright field microscopy, negative staining is typically performed using a black ink fluid such as nigrosin and India ink. These are the acid stains. 

Due to the negative charged chromogen and negative charge on the cell wall of bacteria,…

Different types of Microbial Staining Techniques

Bacteria can be studied either in unstained (wet mount) or stained preparation. By staining any bacterial cell, we can easily identify its cell shape and other easily locate them under the microscope. Different type of staining methods has been evolved time to time to study bacterial cells / cells under the microscope. 

Wet mount preparation: 

Wet mount preparation is useful for the…

Hello everyone,Today's topic of discussion is "Negative Stain"

You can also find information about Gram staining here

Negative staining

is an established method,  easy, rapid, qualitative method often used in diagnostic microscopy, for contrasting a thin specimen with an optically opaque fluid. In this technique, the background is stained, leaving the actual specimen untouched, and thus visible. This contrasts with 'positive staining', in which the actual specimen is stained.The negative stain is particularly useful for determining cell size and arrangement. It can also be used to stain cells that are too delicate to be heat-fixed.

Eg of negative stain used :

nigrosin, ammonium molybdate, uranyl acetate, uranyl formate, phosphotungstic acid, osmium tetroxide, osmium ferricyanide and auroglucothionate

Principle of Negative Staining:

Negative staining requires an acidic dye such as India Ink or Nigrosin.India Ink or Nigrosin is an acidic stain. This means that the stain readily gives up a hydrogen ion (proton) and the chromophore of the dye becomes negatively charged. Since the surface of most bacterial cells is negatively charged, the cell surface repels the stain. The glass of the slide will stain, but the bacterial cells will not. The bacteria will show up as clear spots against a dark background.

Reagents of Negative Staining

India ink, Nigrosin (Nigrosin 100 gm/L, Formalin 5 ml/L in water)

To read the procedure , Advantages and limitations of Negative stain vist our site http://microamaze.blogspot.in/2015/11/negative-stain.html

https://www.blogger.com/blogger.g?blogID=5065214763789161932#allposts

With love