STAINING TECHNIQUES IN BACTERIOLOGY
Staining is a process of coloring the cells using special treatments and methods.
Bacteria is semitransparent in nature. So, it is very difficult to visualize. If it is
stained with any one of the dyes, it increases its visibility.
Objectives of staining
To make contrast in color with the surrounding and to increase its
visibility of bacteria.
To demonstrate the external and internal features of the organism.
To see the size and shape of organism
Difference between Stain and Dye
Dye is a general term used for all colored compound while stain is used for
biological substance. They are organic compound containing two groups;
Chromatophore group; responsible for coloring property of the dye-
presence of chromogen
Auxochrome group; responsible for the binding of chromophore
Dyes
3 types
Cationic (basic)
Anionic (acidic)
Neutral
CATIONIC DYES
It is positively charged. Basic dyes bind to negatively charged molecules like
DNA, nucleic acids.
Eg; Carbol fuchsin, basic fuchsin, methylene blue, crystal violet, malachite
green
Staining is a process of coloring the cells using special treatments and methods.
Bacteria is semitransparent in nature. So, it is very difficult to visualize. If it is
stained with any one of the dyes, it increases its visibility.
Objectives of staining
To make contrast in color with the surrounding and to increase its
visibility of bacteria.
To demonstrate the external and internal features of the organism.
To see the size and shape of organism
Difference between Stain and Dye
Dye is a general term used for all colored compound while stain is used for
biological substance. They are organic compound containing two groups;
Chromatophore group; responsible for coloring property of the dye-
presence of chromogen
Auxochrome group; responsible for the binding of chromophore
Dyes
3 types
Cationic (basic)
Anionic (acidic)
Neutral
CATIONIC DYES
It is positively charged. Basic dyes bind to negatively charged molecules like
DNA, nucleic acids.
Eg; Carbol fuchsin, basic fuchsin, methylene blue, crystal violet, malachite
green
