04
Oct
For negative staining of smears. The India ink stain or the fluorescent stain the commercially available Calco-Fluor white stain is important in screening CSF samples of patients with suspected cryptococcal meningitis.
Culture of a CSF sample is required to confirm the diagnosis.
India ink stain microbiology. India Ink preparation is usually employed to detect the presence of microorganisms particularly yeast in a body fluid. It induces negative staining by. Microbiologists use India ink to stain a slide containing micro-organisms.
The background is stained while the organisms remain clear. This is called a negative stain. Medical researchers use India ink to visualize blood vessels when viewed under a microscope.
In negative staining method an acidic dye is used known as India Ink or Nigrosin. When the bacterial cells are exposed to this stain due to the presence of acidic nature it readily gives up a hydrogen ion proton and the chromophore. Negative staining requires an acidic dye such as India Ink or Nigrosin.
India Ink or Nigrosin is an acidic stain. This means that the stain readily gives up a hydrogen ion proton and the chromophore of the dye becomes negatively charged. Since the surface of most bacterial cells is negatively charged the cell surface repels the stain.
The glass of the slide will stain but the bacterial. India ink is used as a negative stain in negative staining that uses ion negative staining method permits visualization of the usually transparent and unstainable capsules of various micro- microorganisms like Cryptococcus neoformans most commonly Klebsiella pneumoniae Streptococcus pneumoniae etc. Principle of India Ink.
The use of India Ink is not technically a staining method. The polysaccharide capsule of encapsulated organisms eg. Cryptococcus neoformans excludes the ink particles.
Organisms are detected by the appearance of a distinctive halo surrounding the encapsulated fungi. A India-ink was used to stain the background around these cells of the yeast Cryptococcus neoformans. The halos surrounding the cells are the polysaccharide capsules.
B Crystal violet and copper sulphate dyes cannot penetrate the encapsulated Bacillus cells in this negatively stained sample. Encapsulated cells appear to have a light-blue halo. In this staining process instead of ells background is stained.
Here an acidic dye like nigrosin or Indian ink is used. Acidic stain carries a negative charge and repelled by the bacteria which also carry a negative charge on their surface. Hence an acidic dye do not stain bacteria Instead it forms a deposit around the organism leaving the.
For negative staining of smears. Take a clean grease free glass slide. Put a large loopful of undiluted India ink on the slide.
Then add a small loopful of liquid bacterial culture to the India ink and emulsify. Take a clean grease free cover slip and place on the ink drop and press it down so that the film becomes very thin and thus pale in. The India ink stain is currently recommended for the microscopic detection of cryptococci.
There is very little published data on the utility of the Gram stain. We therefore undertook a comparative evaluation of the Gram stain and India ink stain for the rapid diagnosis of cryptococcal meningitis in. The stain is a suspension of carbon found in India ink or nigrosin.
The carbon particles are negatively-charged as is the cell membrane. The background looks black or sepia colored and the cells remain clear since they repel the dye. Some positively charged inclusion bodies such as sulfur may stain.
The India ink stain or the fluorescent stain the commercially available Calco-Fluor white stain is important in screening CSF samples of patients with suspected cryptococcal meningitis. The test is positive in 50 of patients but false-positive results can occur. Culture of a CSF sample is required to confirm the diagnosis.
Using India Ink for visualizing the cerebral spinal fluid indicating that particles of ink pigments can not enter the cell capsule surrounding the yeast cells. This forms a zone of clearance known as a halo around the cells. This is a quick method for the identification of Cryptococcus neoformans.
Consist of four steps. The smear is covered with Crystal violet for 1 minute and washed with water. It is then covered with Lugolsiodine Kept for 1 minute and washed with water.
The smear is covered with alcohol and is washed with water immediately. Under the microscope the India ink stain is used for easy visualization of the capsule in cerebral spinal fluid. The particles of ink pigment do not enter the capsule that surrounds the spherical yeast cell resulting in a zone of clearance or halo around the cells.
This unit describes two methods of capsule staining. The first is a wet-mount method using india ink. The capsule is visualized as a refractile zone surrounding a cell.
The second is a direct-staining dry-mount method that precipitates copper sulfate and leaves the capsule as a pale blue zone. Both methods are easily performed within 5 min. India ink staining is a negative staining technique used to determine an organisms cellular morphology.
The background is stained whereas the organism remains unstained and the morphology is not distorted in any way. Capsules displace the dye and appear as halos surrounding the organism. String or threadlike bacteria Chains of cells which can extend from the floc grow within the floc or even free in the bulk water.
Prevent effective settling by interfering with floc formation bulking. Can be helpful in small quantities acting as a backbone for floc to form. Commonly used microbiological stains generally fall into one of two categories - basic stains or acidic stains although there are a few stains such as India Ink which are neutral.
A basic dye is a stain that is positively charged and will therefore react with material that is negatively charged. Stain microbiology Any colored organic compound usually called dye used to stain tissues cells cell components or cell contents. The dye may be natural or synthetic.
The object stained is called the substrate. The small size and transparency of microorganisms make them difficult to see even with the aid of a high-power microscope.