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What else can I help you with?
Acidic Congo red does not contain carbon particles like Nigrosin but can give the appearance of a negative stain What is the basis for this stain?
Acidic Congo red is a negatively charged dye that can stain the background of a specimen, giving the appearance of a negative stain. This effect is due to the electrostatic repulsion between the negative charge of the dye and the negatively charged cellular components, causing the dye to be excluded from the cells and stain the background instead.
What is secondary and counter stain?
counterstains are selected to be contrasting color so that the target of the primary stain can easily be differentiated on a contrasting background. This makes life easier, when, for example you need to count the number of nuclei in a smear, or number of gram positive bacteria in a mixed population.
Could a negatively charged dye stain a bacteria?
The effect on the bacteria depends if the stain is an acidic or basic stain. Most bacteria are stained when a basic stain permeates the cell wall and adheres by weak ionic bonds to the bacterial cell, which is slightly negatively charged.
What is the stain used to staines the cell membrane?
The stain commonly used to stain the cell membrane is called lipophilic fluorescent dyes, such as DiI or DiO, which incorporate into the cell membrane due to their hydrophobic nature. These dyes are often used in microscopy to visualize cell membranes within cells or tissues.
Which phylum contains bacteria with gram positive cellwall?
The phylum containing bacteria with gram-positive cell walls is Firmicutes. These bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain in the Gram staining procedure.
Does the gram stain procedure work for all bacteria?
Yes. The gram stain procedure separates all bacteria into one of two groups - into gram-negative bacteria which do not stain purple and into gram-positive cells which do stain purple. In structural terms, the ability of a cell to become stained during the gram stain procedure is due to the chemical makeup of the cell wall.
A stain that does not penetrate cell use to color background?
A counterstain is a dye that highlights structures or elements in a background while not staining certain structures or areas, such as the cell itself. This technique is commonly used in microscopy to visualize specific components of a sample against a contrasting background. Examples include hematoxylin as a nuclear stain and eosin as a cytoplasmic stain in histology.
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.
Why is the technique called negative staining?
Because the cell wall repels the binding of the negative stain therefore the cells do not stain. Because of this the background is stain with the dye used and the bacteria remain colorless. Basically your staining the background, that is, you are not directly staining the cells.
What is the importance of iodine after primary stain?
Iodine is used after the primary stain in the Gram stain procedure to form a complex with the crystal violet dye, which helps to stabilize the dye within the bacterial cell wall. This step enhances the retention of the primary stain in Gram-positive bacteria.
What is the color of the capsule in the capsule stain?
When a stain, such as an acid dye, cannot penetrate the outer layers of a microbe, the cell will appear transparent on a colored background. This stain is called a negative or background stain. It is performed by mixing the dye with a suspension of bacteria on a slide and spreading the mixture into a thin layer for viewing. The capsule is a structure surrounding the cell wall that certain bacteria can produce. The ability to form a capsule is genetically and environmentally controlled. Only those microbes with the genes for capsule production have the potential to manufacture this polysaccharide (or polypeptide) surface layer. Special nutrients or other growth factors often are necessary for the genes to be expressed. The role of the capsule is primarily for protection of the bacteria. For example, the capsule affords a seal against dehydration. Many capsules repel white blood cells and thus allow pathogenic invading bacteria to elude one of the primary host defenses. Capsules are not readily stained and therefore are visualized by negative stain techniques. The organisms are prepared as a smear in the presence of an acid dye and allowed to air dry because heat will cause the capsule to shrink. Our procedure will combine a negative stain (which colors the background) and a simple stain to color the bacterial cell. The capsule appears as a colorless layer between the bacterium and the background.
Why doesn't the whole cell stain with the cell-wall stain?
The whole cell doesn't stain during a cell wall stain because the dyes that are used are only attracted to the negative cell wall and only sticks it. The inside of the cell shows clear.
What is the purpose of the heat during the acid fast staining procedure?
The heat is used to drive the primary stain, carbol fuchsin, into the waxy cell wall of acid-fast bacteria. This allows the stain to penetrate the mycolic acid in the cell wall, making the bacteria resistant to decolorization with acid-alcohol.
Acidic Congo red does not contain carbon particles like Nigrosin but can give the appearance of a negative stain What is the basis for this stain?
Acidic Congo red is a negatively charged dye that can stain the background of a specimen, giving the appearance of a negative stain. This effect is due to the electrostatic repulsion between the negative charge of the dye and the negatively charged cellular components, causing the dye to be excluded from the cells and stain the background instead.
What prevents the cell from appearing green in the finished endospore stain?
The endospore stain uses malachite green, but this dye is rinsed off the cell during the staining procedure. The endospore itself retains the green color due to its resistance to decolorization, making it appear green against a contrasting counterstain like safranin.
What is secondary and counter stain?
counterstains are selected to be contrasting color so that the target of the primary stain can easily be differentiated on a contrasting background. This makes life easier, when, for example you need to count the number of nuclei in a smear, or number of gram positive bacteria in a mixed population.
Explain the function of Copper Sulfate in the spore staining procedure?
From what i read in my book: Because the capsule is nonionic, unlike the bacterial cell, the primary stain adheres to the capsule without binding to it. Since the capsule is water- soulube, copper sulfate, rather than water, is used to wash the purple primary stain out of the capsular material without removing the stain that is bound to the cell wall.
