What is the purpose of the heat during the acid-fast staining procedure?

What is the purpose of the heat during the acid-fast staining procedure?

During the acid fast stain, heat is used as a mordant to allow the primary stain to penetrate the waxy mycolic acid layer. The heat will prevent the cells from being destained using acid-alcohol.

Why do you heat fix bacterial cells when preparing a smear?

Heat fixation ensures the elimination of contaminating organisms from the smear preparation. Heat fixation adheres the cells to the slide and coagulates the bacterial proteins, effectively killing the bacteria.

What would be the effect of heat fixing the bacterial cells during the capsule stain procedure?

THE CAPSULE STAIN – The Gin Stain Most bacterial capsules are composed of polysaccharide however some genera produce polypeptide capsules. Capsular material is very moist (slimy) and any heating will cause it to shrink – it is for this reason that we will not heat fix the slide before staining.

Does heat fixing coagulate cytoplasmic proteins?

Heat-fixing kills the bacteria, makes them adhere to the slide, and coagulates cytoplasmic proteins to make them more visible. It also distorts the cells to some extent.

Why does the bacterial smear needs to be heated when performing acid-fast staining and spore staining?

The heat “melts” the waxy cell wall and permits the absorption of the dye by the cells. Cells that are “acid-fast” because of the mycolic acid in their cell wall resist decolorization and retain the primary stain. All other cell types will be decolorized. Methylene blue is then used as a counterstain.

What is the purpose of steaming the bacterial smear before staining?

Steam helps to loosen up the waxy layer and promotes entry of the primary stain inside the cell. The smear is then rinsed with a very strong decolorizer, which strips the stain from all non-acid-fast cells but does not permeate the cell wall of acid-fast organisms.

What does heat fixation of a bacterial smear accomplish?

heat fixation of smears kills the bacterial cells and causes them to adhere to the glass so that they do not get washed off during staining. overheating can damage and dehydrate the cells causing them to distort in shape.

Why do we heat fix the smear before staining it?

What is heat-fixing? You heat fix a slide so the bacteria don’t wash off during the staining process.

How does heating the bacterial smear promote entry of stain in the cell wall?

How does heating the bacterial smear during a ZN stain promote entry of carbolfuchsin into the acid-fast cell wall? Heating melts the mycolic acid and allows the stain to penetrate the cell walls. The nonacid-cells are then counterstained with brilliant green to show the difference.

What is the purpose of heat fixing a smear?

Heat fixing kills cells, and adheres them to the slide. Cells will be rinsed off the slides if they are not heat fixed properly.

What happens to bacteria when exposed to heat?

When the temperature gets hot enough, the enzymes in the bacterium are denatured, meaning they change shape. This change renders them useless, and they’re no longer able to do their work. The cell simply ceases to function. Heat can also damage the bacterium’s cell envelope.

Why is heat necessary in spore staining?

apply heat to assist stain penetration. The heat will force the stain into the spores and vegetative cells, and both will become green. By rinsing the slide, the vegetative cells will lose their color but the spores will remain green.