Purpose Of Gram Staining

Purpose Of Gram Staining

Laboratory exercise vi micro
Make your bacterial smear and heat fix it as done for the simple stain procedure.Let the smear cool totally.Cover the smear with Crystal violet stain for one (1) minute.Rinse with water from the squirt bottle.

Cover the smear with Grams iodine for one (1) minute.

Rinse with water from the squirt bottle.

Decolorize with Grams alcohol.

Hold slide at an angle at a time until stain stops running off.(Three to four drops should be sufficient.) Rinse with water from the squirt bottle.

Rinse with water from the squirt bottle.Blot the smear dry with bibulous paper.12.Examine the smear under 100X after first focusing on 10X.

Questions:imary stain in this procedure? ondary stain in this procedure? Why is Grams iodine called a mordant?

in the Gram stain procedure? 5.

Why do some bacteria turn purple and otprocedure?.
Gram stain
1The Gram staining method is named after the Danish bacteriologist Hans Christian Gram (1853 1938) who originally devised it in 1882 (but published in 1884), to discriminate between pneumococci and Klebsiella pneumoniae bacteria in lung tissue.It is a differential staining method of differentiating bacterial species into two large groups (Gram-positive and Gram-negative) based on the chemical and physical properties of their cell walls.This rtwo fundamental groups according to their stainability and is one of the basic foundations on which bacterial identification is built.Gram staining is not used to classify archaea, since these

Primary stain (Crystal violet, me Mordant (Gram's Iodine)

Decolourizer (ethyl alcohol, accetone mixture)

Counterstain (Dilute carbol fuchsin, safranin or neutral red) The original description of staining technique by Christian Gram in a

publication titled "The differential staining of Schizomycetes in tissue sections and in dried preparations" in Fortschitte der Medicin; 1884, Vol
purpose of gram staining
Gram’s Staining
1 Gram’s staining The Gram staining method is named after the Danish bacteriologist Hans Christian Gram (1853 – 1938) who originally devised it in 1882 (but ... (itc.csmd.edu)
Gram Staining Of Bacteria - Tracy High Adv Bio And Biotechnology
Name_____ Date_____Per. _____ Gram Staining of Bacteria The purpose of Gram staining is to determine one characteristic property of (microrao.com)
Simple Stain And The Gram Stain - Florida International …
EXPERIMENT 2 SIMPLE STAIN and the GRAM STAIN In most microbiological staining procedures, the bacteria are first fixed to the slide by the heat fixed smear. (jkirkbrown.com)
.2, pages 185-189 was slightly different from what we use today.The primary stain used was aniline gentian violet, mordant was Lugol's iodine (iodine-potassium iodide The smear on a glass slide is coveimary stains.Gentian violet is a mixture of methyl violet and crystal violet.The primary stain renders all the bacteria uniformly ng solution, the slide is washed in water.

The smear is treated with few drop of Gram's Iodine and allowed to act for a minute.

This results in formation of a dye-iodine complex in the cytThe slide is again washed in water and then decolorized in absolute ethyl alcohol or acetone.A mixture of ecetone-ethyl alcohol (1:1) can also be used for decolorization.

The process of decolorization is fairly quick and should not exceed 30 seconds for thin smears.Acetone is a potent decolorizer and when used alone can decolorize the smear in 2-3 seconds.

A mixture of ethanol and acetone acts more slowly than pure acetone.Decolorization is the most crucial part of Gram staining and errors can occur here.Prolonged decolorization can lead to over-decolorized od may lead to under-decolorized smear.

After the smear is decolorized, it is washed in water without any delay.The smear is finally treated with few drops of counterstain such as dilute.
Let completely dry.Pass the slide though the flame three times.

Do not heat slide very hot.

This is to fix the bacteria to the slide, not burn them to it.Cover the slide with Crystal Violet stain.

Let stand one minute.Pour off excess stain.

Dip slides in water two or three times to remove excess stain.

Drain excess water.

Cover slide with Grams Iodine.

Let stand one minute.Pour off excess Iodine and Dip in water two or three times to remove excess iodine.and let run over the smear.

After 2-3 Cover slide in Safranin O stain and let sit for one minute.Drain excess water and allow to dry completely.

This can be examined under high power or oil immersion..
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