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Because Nigrosin is an acidic dye--carries a negative charge--and repels against the negatively charged cell walls of most bacteria.
Wiki User
∙ 14y ago
Wiki User
∙ 14y agoBecause it has a negative charge like the cell wall of the bacterial cell so it can't penetrate the cell wall.
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Why cant methylene blue be used in place of nigrosin in negative staining?
Because negative staining requires the use of an acidic stain, which will not penetrate the cells because of the negative charge on the surface of the bacteria. As a result, the unstained cells can be easily identified against the colored background.
Why doesn't a negative stain colorize the cells in the smear?
A negative stain will stain the background with an acidic dye, such as Nigrosin. This procedure is used to demonstrate capsules. This technique brings the specimen off of the background for more adequate viewing purposes.
What are the materials used in capsule stain?
For the capsule stain Congo red or a Nigrosin solution can be used. Next, Maneval's stain is used.
What causes a stain to adhere to bacterial cells?
In a gram positive stain it is because the cell's cell wall is made up of peptioglycan
Describe the microscopic appearance of encapsulated streptococcus if stained with 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
Can you stain a staphylococcus specimen with nigrosin?
Nigrosin is a dye made of synthetic ingredients. it is a negative stain, which is what is required to be able to stain staphylococcus.
Why cant methylene blue be used in place of nigrosin in negative staining?
Because negative staining requires the use of an acidic stain, which will not penetrate the cells because of the negative charge on the surface of the bacteria. As a result, the unstained cells can be easily identified against the colored background.
What would the slide look like under the microscope if methylene blue is used instead of nigrosin?
The stain would stain the cells rather than the background
Why doesn't a negative stain colorize the cells in the smear?
A negative stain will stain the background with an acidic dye, such as Nigrosin. This procedure is used to demonstrate capsules. This technique brings the specimen off of the background for more adequate viewing purposes.
What is a negative stain?
The negative staining techniques uses a dye solution in which the chromogen is acidic and carries a negative charge. (An acidic chromogen gives up a hydrogen ion, which leaves it with a negative charge.) The negative charge on the bacterial surface repels the negatively charged chromogen, so the the cell remains unstained against a colored background.
Are nigrosin and malachite green a functional analogous pair of stain?
No
Is it possible to substitute methylene blue for nigrosin in the negative stain?
no
What are the materials used in capsule stain?
For the capsule stain Congo red or a Nigrosin solution can be used. Next, Maneval's stain is used.
What causes a stain to adhere to bacterial cells?
In a gram positive stain it is because the cell's cell wall is made up of peptioglycan
What color are gram negative cells?
Gram positive bacterial stain purple. They do not take up the counter stain.
Describe the microscopic appearance of encapsulated streptococcus if stained with 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
Can you heat fix blood smear before staining for bacterial examination?
You absolutely do not heat fix a blood smear before staining, that is, if you are looking at the blood cells. For bacteria, why wouldn't you culture it first and then heat fix, stain etc. I don't think heat fixing the blood stain would damage the bacterial cells so much as make it hard to differentiate the bacterial cells from the dead, shriveled, ruined blood cells, unless maybe you have like an electron microscope or something.
