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A Ziehl–Neelsen stain is an acid-fast stain used to stain species of Mycobacterium tuberculosis that do not stain with the standard laboratory staining procedures such as Gram staining. This stain is performed through the use of both red coloured carbol fuchsin that stains the bacteria and a counter stain such as methylene blue .
In pap smears, Light Green SF confers a blue staining for the cytoplasm of active cells such as columnar cells, parabasal squamous cells, and intermediate squamous cells. [3] It usually comes as a disodium salt. Its maximum absorption is at 630 (422) nm. The dye is not very durable — it has a tendency to fade.
Gram-positive cells have a thick layer of peptidoglycan in the cell wall that retains the primary stain, crystal violet. Gram-negative cells have a thinner peptidoglycan layer that allows the crystal violet to wash out on addition of ethanol. They are stained pink or red by the counterstain, [3] commonly safranin or fuchsine.
In contrast, basic dyes are used to stain cell nuclei and some other acidic components of tissues. [8] Regarding cellular structures, acid dyes will stain acidophilic structures that have a net positive charge due to the fact that they have a negatively charged chromophore. Acidophilic structures include the cytoplasm, collagen and mitochondria ...
It is used as a food coloring, [11] printing ink, [12] biological stain, [13] dental plaque disclosing agent, [14] radiopaque medium, [13] sensitizer for orthochromatic photographic films, and visible light photoredox catalyst. [15] Erythrosine is commonly used in sweets, such as some candies, ice pops and cherries, and in cake-decorating gels ...
The material that is trapped coats the underlying material, and the stain reflects backlight according to its own color. Applied paint, spilled food, and wood stains are of this nature. [5] A secondary method of stain involves a chemical or molecular reaction between the material and the staining material. Many types of natural stains fall into ...
It is used as a food coloring agent, and the color is sensitive to pH. Other betalains known to occur in beets are isobetanin, probetanin, and neobetanin. The color and antioxidant capacity of betanin and indicaxanthin (betaxanthin derived of l -proline ) are affected by dielectric microwave heating. [ 10 ]
A "vital dye" or stain is a dye capable of penetrating living cells or tissues without causing immediate visible degenerative changes. [26] Such dyes are useful in medical and pathological fields in order to selectively color certain structures (such as cells) in order to distinguish them from surrounding tissue and thus make them more visible ...