STAINING

STAINING

an auxiliary technique used in microscopy to enhance contrast in the microscopic image.

STAINS AND DYES

are frequently used in biology and medicine to highlight structures in biological tissues for viewing, often with the aid of different microscopes.

FIXING

process of attaching cells to a slide. 

FIXATION

• achieved either by heating (heat fixing) or chemically treating the specimen.

• also kills microorganisms in the specimen, stopping their movement and metabolism while preserving the integrity of their cellular components for observation.

SIMPLE STAINING

• uses only one stain or dye.  

• It can be performed with basic dyes such as crystal violet or methylene blue,

• positively charged dyes that are attracted to the negatively charged materials of the microbial cytoplasm.

• determine cell shape, size and arrangement.

• Other dye includes crystal violet and safranin.

CRYSTAL VIOLET
METHYLENE BLUE
SAFRANIN

BASIC DYES USED IN SIMPLE STAINING

NEGATIVE STAINING

• uses a single dye just like simple staining.  

• It is done by using acidic dyes such as nigrosin or congo red, negatively charged dyes that are repelled by the negatively charged cytoplasm.  

• The dye gathers around the cell and leaves the cell clear and unstained.  

NIGROSIN
CONGO RED

ACIDIC DYES USED IN NEGATIVE STAINING

DIFFERENTIAL STAINING

distinguishes two kinds of organisms therefore differentiating one group from another group of organism.

GRAM-STAINING

differential technique that separates bacteria into two groups, gram-positive and gram-negative bacteria.

ACID-FAST STAINING

A technique that differentiates species of Mycobacterium from other bacteria.  

CARBOLFUCHSIN

Heat or a lipid solvent is used to carry the first stain, ___, into the cells.

BRIGHT RED

ACID-FAST BACTERIA APPEAR ___

BLUE

NONACID-FAST BACTERIA APPEAR ___

Mycobacterium leprae

causes leprosy

Mycobacterium tuberculosis

causes tuberculosis

SPECIAL STAINING

used to identify various bacterial structures of importance.

FLAGELLA STAINING

A special technique that highlights the flagella of bacteria by coating the flagella with dyes or metals to increase their widths.

SPORE-STAINING

A special staining technique that is used to examine bacterial spores.

MALACHITE GREEN

DYE USED TO GIVE COLOR TO SPORE-FORMING BACTERIA

SAFRANIN

DYE USED TO GIVE COLOR TO NON-SPORE FORMING BACTERIA

GREEN

COLOR OF SPORE-FORMING BACTERIA

RED

COLOR OF NON-SPORE FORMING BACTERIA