WK 3 Flashcards
PURPOSE OF STAINING SPECIMEN
- Increase visibility of specimen
- Differentiate one organism from another
o Some microorganism will take color under a given
condition. In that case, we will be able to differentiate
one bacteria to another
o Just like in the use of differential stains like AFB stains
or Gram stains - Accentuate specific morphological features
o There are the so-called differential stains, which react
only with particular structures of bacteria.
o Example: specific stain will only color the spore; stain
to color the metachromatic granules - Preserve specimen
o By putting on cover slip with an adhesive and it will
preserve the morphology
react
only with particular structures of bacteria
DIFFERENTIAL STAINS
HOW TO PRESERVE SPEIMEN
By putting on cover slip with an adhesive and it will
preserve the morphologY
coloring agent used for general purposes
DYE
dye used for biological purposes (specific)
STAIN
derived from coal tar
rendered synthetically to become a stain
ANILINE DYE
Colorless organic compound that can bind to the nitro
group of chromophores.
HIGHLY TOXIC SILA
BENZENE
Chemical groups with conjugated double bonds,
imparts color to the colorless benzene
CHROMOPHORE
CHROMOPHORE PLUS BENZENE MAKES
CHROMOGEN
EXAMPLE OF CHROMOPHORE
NITRO GROUP
Groups that intensify the color of chromophore by
conveying the property of ionization to the chromogen
and enabling it to form salts and binding to the
biological substance
AUXOCHROME
EXAMPLE OF AUXOCHROME
HYDROXYL GROUP
organic compound
containing both chromophores and auxochrome link to the
benzene.”
STAIN
responsible for transferring the color of the
dye to a substance or material to which the dye will act upon
AUXOCHROME
STAIN BASED ON RIGIN
NATURAL AND SYNTHETIC
NATURAL = HEMATOXYLIN AND CARMINE
SYNTHETIC = SAFRANIN, METHYLENE BLUE, CRYSTAL VIOLET
STAIN BASED ON PURPOSE
DIRECT, INDIRECT, SELECTIVE AND DIFFERENTIAL
DIRECT = ANILINEDYES
INDIRECT = INDIA AND NIGROSIN
Selective – particular parts of the organism like the flagella or spore of bacteria
Differential – differentiate two groups of bacteria in mixture
STAIN BASED ON STAINING ACTIVITY
NUCLEAR, CYTOPLASMIC AND HISTOLOGIC
NUCLEAR = HEMATOXYKLINE AND CARMINE
CYTOPLASMIC= ANILINE BLUE AND EOSIN
HISTOLOGIC = SAFRANIN
STAIN BASED ON CHARGE
ACIDIC , BASIC AND NEUTRAL
negatively-charged chromophore, anionic;
more affinity to positively-charged cellular components
such as protein
ACIDIC STAIN
positively-charged chromophore, cationic,
more affinity for negatively-charged cellular
constituents such as the DNA and RNA
BASIC STAIN
WHAT ISTHE CHARGE OF BACTERIA
NEGATIVE
EXAMPLE OF BASIC DYE
CYRSTAL VIOLET, METHYLENE BLUE, HEMATOXYLIN, GENTIAN VIOLET
both having positive and negative charge
NEUTRAL STAIN
NEUTRAL STAIN EXAMPLE
GIEMSA, LISHMAN, WRIGHT AND ROMANOWSKY WHICH IS USED FOR HEMATOLOGY
DISTRIBUTION OF BACTERIAL CELL IN A SLIDE IN ORER TO VIEW THEM IN A MICROSCOPE
SMEAR
WHAT HAPPENS IF BACTERIAL INOCULUM IS SPREAD TOO THICK OR TOO THIN
If too thick, you will not appreciate the morphology because
they are too crowded. And if it is too thin, you will not be
able to see it
Process by which internal and external structures are
preserved and fixed in position
FIXATION
Process by which organism is killed and firmly attached to
microscope slide
FIXATION
Protein will be coagulated and the bacterial cell will
adhere to the slide
HEAT FIXZATION
Preserves overall morphology but not internal
structures
HEAT FIXATION
Protects cellular structure and morphology of
larger and more delicate organisms
CHEMICAL FIXATION
CHRMICAL FIXATION IS DONE VIA
Done through application of methanol or any
alcohol (dipping it for 5 to 6 times); it has to be
dried first before staining
- Direct stains the bacteria
positive stain
Where the actual cells are being imparted with color. They
will appear in a clear background having color so they are
being contrasted from the environment. Colored bacterial
cell stands out.
positive stain