What is the wavelength of maximal absorbance for crystal violet?
Absorbance Characteristics The ratio of the absorbance at A 15 nm to the absorbance at A + 15 nm should be between 0.98 and 1.9 (A is the wavelength of maximum absorption obtained in the assay).
In which experiment would you use crystal violet solution?
In forensics, crystal violet was used to develop fingerprints. Crystal violet is also used as a tissue stain in the preparation of light microscopy sections.
Why is crystal violet useful?
Crystal violet is also a mitotic agent and mutagen. It has been used for topical treatment in creams against fungal and bacterial infections. Its been used against some pathogenic fungi such as Candida species and some gram-positive bacteria, e.g. Staphylococcus species.
Is Crystal Violet a disinfectant?
Crystal violet or methyl violet is used in many applications, including: As a pH indicator (yellow to violet with the transition at a pH = 1.6) In the medical community, it is the active ingredient in Gram’s Stain, used to classify bacteria. The dye destroys cells and is used as a moderate-strength external …
Is Crystal Violet a carcinogen?
Inspite of its many uses, CV has been reported as a recalcitrant dye molecule that persists in environment for a long period and pose toxic effects in environment. It acts as a mitotic poison, potent carcinogen and a potent clastogene promoting tumor growth in some species of fish.
Is Crystal Violet a basic dye?
If the color portion of the dye resides in the positive ion, as in the above case, it is called a basic dye (examples: methylene blue, crystal violet, safranin). If the color portion is in the negatively charged ion, it is called an acidic dye (examples: nigrosin, congo red).
Is Crystal Violet a positive or negative stain?
Simple Stain Basic stains, such as methylene blue, Gram safranin, or Gram crystal violet are useful for staining most bacteria. These stains will readily give up a hydroxide ion or accept a hydrogen ion, which leaves the stain positively charged.
Does crystal violet stain live or dead cells?
Crystal violet will in fact stain living cells (though it is toxic) as well as dead cells. The viability assay is only to be used on adherent cells. It does not differentiate live and dead cells on the plate, the dead cells are simply washed off because they are no longer adherent.
Is a simple stain positive or negative?
Simple stains use basic dyes which are positively charged. These positive dyes interact with the slightly negatively charged bacterial cell wall thus lending the color of the dye to the cell wall. The slide to the right shows a cocci that has been stained with crystal violet.
Is safranin a negative stain?
In Gram’s staining, the safranin directly stains the bacteria that has been decolorized. With safranin staining, the gram-negative bacteria can be easily distinguished from gram-positive bacteria.
Which can be used to produce a negative stain?
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.
Is a simple stain acidic or basic?
Flagella StainingTable 2. Simple StainsStain TypeSpecific DyesBasic stainsMethylene blue, crystal violet, malachite green, basic fuschsin, carbolfuschsin, safraninAcidic stainsEosine, acid fuchsin, rose bengal, Congo redNegative stainsIndia ink, nigrosine
Is carbol Fuchsin acidic or basic?
The primary stain for the Ziehl-Zeelsen procedure is the aniline dye, basic fuchsin, that stains all the cells present red. The unique ability of mycobacteria to resist decolorization by acid-alcohol is why they are termed acid-fast, and will keep their red coloration throughout the staining process.