Crystal violet is used first to stain all bacteria purple. However, when you immerse the bacteria then in alcohol, alcohol affects the permeability of the peptidoglycan layer to crystal violet, blocking its exit from gram-positive cells. This way, gram-positive cells remain purple while gram-negative cells are colourless. Safranin red is then used as a counterstain to make the two types of bacteria more differentiable.
it stains the gram negative that got decolorised by ethanol.Gram-positive cells stain purple because they retain the crystal-violet dye in their cell walls.
Safranin stains G- bacteria red.
it give color of gram negative bacteria
identification of bacteria strains
Gago
safranin
Safranin (red) is used in gram staining and endospore staining as the secondary stain. Nigrosin is used in negative staining, staining only the background and not the bacteria. Therefore, the bacteria within the capsule would stain red from the safranin. (Like in endospore staining and negative gram staining, safranin would stain the bacteria red.) Nigrosin would stain the background of the organism just as it would in negative staining. Bacteria (within capsul): stained safranin red Capsule (outer layer of bacteria): clear Background of organism: stained dark with Nigrosin
The steps in Gram staining are:1. crystal violet added to the smear2. iodine, the mordant (this fixes the violet)3. a decolorizer made of acetone and alcohol4. safranin, the counterstainIf the cell is Gram +, the decolorizer can not remove the violet. If it is Gram -, the decolorizer can remove the violet and the cell can be then colored with the dye, safranin.Bacteria are grouped in 4 groups by Gram stain:Gram-positive, the cell wall retains crystal Violet.Gram-negative, the cell wall does not retain crystal Violet.Graham not reactive, no staining whatsoever.Graham variable, uneven staining.
Both processes use 2 stains. The Gram staining process uses crystal violet as the primary stain and safranin as the secondary stain. Acid-fast staining uses carbol fuchsin as the primary and methylene blue as the secondary.
____________Color of Gram-positive_______Color of Gram-negativePrimary stainCrystal violet_____Purple____________________ PurpleMordant:Iodine____________Purple________________________PurpleDecolorizing agent:Alcohol-acetone__ Purple____________________ ColorlessCounterstain:Safranin___________Purple_________________________Red
safranin
No. safranin is the classic stain used in gram staining. Concentrated Carbol Fushin is mainly used for the ZN staining procedure to stain organisms such as Vibrio cholerae and Cryptosporidium. Diluted Carbol Fushin can however be used as a replacement counterstain for Safranin in the gram stain.
Safranin (red) is used in gram staining and endospore staining as the secondary stain. Nigrosin is used in negative staining, staining only the background and not the bacteria. Therefore, the bacteria within the capsule would stain red from the safranin. (Like in endospore staining and negative gram staining, safranin would stain the bacteria red.) Nigrosin would stain the background of the organism just as it would in negative staining. Bacteria (within capsul): stained safranin red Capsule (outer layer of bacteria): clear Background of organism: stained dark with Nigrosin
The steps in Gram staining are:1. crystal violet added to the smear2. iodine, the mordant (this fixes the violet)3. a decolorizer made of acetone and alcohol4. safranin, the counterstainIf the cell is Gram +, the decolorizer can not remove the violet. If it is Gram -, the decolorizer can remove the violet and the cell can be then colored with the dye, safranin.Bacteria are grouped in 4 groups by Gram stain:Gram-positive, the cell wall retains crystal Violet.Gram-negative, the cell wall does not retain crystal Violet.Graham not reactive, no staining whatsoever.Graham variable, uneven staining.
Both processes use 2 stains. The Gram staining process uses crystal violet as the primary stain and safranin as the secondary stain. Acid-fast staining uses carbol fuchsin as the primary and methylene blue as the secondary.
Both bacteria types would be stained by the safranin. When the iodine is added, safranin would be "set" in the positive. The decolorizer would wash out the safranin and then application of the crystal violet would stain the negative.
This is known as a gram test.
fixing the stain so that the first dye which is the crystal violet will not be washed away during rinse process.
____________Color of Gram-positive_______Color of Gram-negativePrimary stainCrystal violet_____Purple____________________ PurpleMordant:Iodine____________Purple________________________PurpleDecolorizing agent:Alcohol-acetone__ Purple____________________ ColorlessCounterstain:Safranin___________Purple_________________________Red
This is simply important in order to have accurate staining results. If this is not followed, the process of the staining will result to false positives or false negatives.
step 1 crystal violet step 2 grams iodine step 3 ethanol step 4 safranin
the Gram reaction is based on the structure of the bacterial cell wall. In Gram-positive bacteria, the dark purple crystal violet stain is retained by the thick layer of peptidoglycan which forms the outer layer of the cell. In Gram-negative bacteria, the thin peptidoglycan layer in the periplasm does not retain the dark stain, and the pink safranin counter stain stains the peptidoglycan layer. In other word,the gram reaction refers to how the cells reacts to the gram-staining process.