Explanation: Gram staining is a type of differential staining. In this process the fixed bacterial smear is subjected to the following staining reagents in the order listed: crystal violet, iodine solution, alcohol (decolorizing agent), and safranin.
What is the Order of staining in Gram staining?
Explanation: Gram staining is a type of differential staining. In this process the fixed bacterial smear is subjected to the following staining reagents in the order listed: crystal violet, iodine solution, alcohol (decolorizing agent), and safranin. Click to see full answer. Consequently, what is the order of reagents used in the Gram stain?
What reagent is used to stain Gram positive and Gram negative?
If done too long, gram-positive can look gram-negative and if done too short, gram-negative and look gram-positive. Which reagent serves this purpose in the gram stain procedure? Gram's iodine What is the function of a mordant? A mordant intensifies a stain or can be used to coat structures such as flagella for viewing.
How do I prepare a Gram stain?
Gram staining requires the use of different chemical reagents which can be purchased in ready to use forms from commercial suppliers or gram stain reagents can be prepared at the laboratory by mixing different chemicals in appropriate amount using standard methods.
Why is the Gram stain considered a differential stain?
Why is the gram stain considered a differential stain? It differentiates gram-positive and gram-negative cell walls based on staining. How do gram-positive and gram-negative bacteria differ in cellular structure, and how does this contribute to their differential staining properties?
How to stain a specimen with gram stain?
The procedure/steps of Gram Stain. Prepare and fix the specimen to the microscope slide before staining. Cover the smear with crystal violet, the primary stain, for 20 seconds. Gently rinse off the stain with water. Cover the smear with Gram’s iodine, the mordant, for 1 minute. Pour off the excess Gram’s iodine.
How to do Gram stain?
The procedure/steps of Gram Stain 1 Prepare and fix the specimen to the microscope slide before staining. 2 Cover the smear with crystal violet, the primary stain, for 20 seconds. 3 Gently rinse off the stain with water. 4 Cover the smear with Gram’s iodine, the mordant, for 1 minute. 5 Pour off the excess Gram’s iodine. 6 Run the acid-alcohol decolorizer over the smear until the solution appears clear. 7 Gently rinse with water. 8 Cover the smear with safranin, the secondary or counterstain, for 20 seconds. 9 Gently rinse the stain with water. 10 Blot dry with bibulous paper.
What is the principle of Gram staining?
Principle of Gram Stain. The two major groups of bacteria can be divided into gram-positive and gram-negative. The Gram stain technique is based on the differential structure of the cellular membranes and cell walls of the two groups. Gram-positive organisms contain a highly cross-linked layer of peptidoglycan that retains the primary dye, ...
How to get rid of iodine stains on a smear?
Pour off the excess Gram’s iodine. Run the acid-alcohol decolorizer over the smear until the solution appears clear. Gently rinse with water. Cover the smear with safranin, the secondary or counterstain, for 20 seconds. Gently rinse the stain with water. Blot dry with bibulous paper.
What is the objective of gram stain?
This test differentiates the bacteria into Gram-Positive and Gram-Negative Bacteria, which helps in the classification and differentiation of microorganisms. The Gram stain separates bacteria into two groups: (1) Gram-positive microorganisms that retain the primary dye (Crystal violet) and ...
What is the primary color of Gram positive organisms?
Gram-positive organisms contain a highly cross-linked layer of peptidoglycan that retains the primary dye, crystal violet (CV), following the application of the mordant, iodine (I). The iodine and crystal violet form a complex within the peptidoglycan.
What stain is used to make gram negative cells pink?
The cells appear colorless. To make the colorless cells visible, a secondary stain, safranin, is applied, leaving the gram-negative cells pink. Created with BioRender.com.
What is the gram staining technique?
Gram staining technique requires simultaneous use of chemical reagents for a fixed period followed by washing; Primary stain (crystal violet), Mordant (iodine), Decolorizer (ethanol or acid-alcohol), and Counterstain (safranin or dilute carbol-fuchsin). Stained slide is air-dried and observed under oil immersion ...
What is Gram staining 2021?
Last updated on June 1st, 2021. Gram staining requires the use of different chemical reagents which can be purchased in ready-to-use forms from commercial suppliers or can be prepared at the laboratory by mixing different chemicals in an appropriate amount. Gram staining technique requires simultaneous use of chemical reagents for ...
What is the best decolorizer for smears?
Decolorizer. Some workers prefer to use acetone by itself, ethanol 95% v/v, or ethanol-iodine as the decolorizing solution. A mixture of acetone-alcohol is recommended because it decolorizes more rapidly than ethanol 95% v/v, and is less likely to over-decolorize smears than acetone without alochol added.