Counterstain
Biological stain whose color contrasts with the principal stain
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/79/Gram_Stain_Anthrax.jpg/200px-Gram_Stain_Anthrax.jpg)
A counterstain is a stain with colour contrasting to the principal stain, making the stained structure easily visible using a microscope.
Examples include the malachite green counterstain to the fuchsine stain in the Gimenez staining technique and the eosin counterstain to haematoxylin in the H&E stain.[1] In Gram staining, crystal violet stains only Gram-positive bacteria, and safranin counterstain is applied which stains all cells, allowing the identification of Gram-negative bacteria as well. An alternative method uses dilute carbofluozide. Counterstains are sometimes used to separate animals from organic detritus in microbiology studies.
References
- ^ Williams, D.; Williams, N. (22 December 2003). "A counterstaining technique for use in sorting benthic sample". Limnology and Oceanography. 19 (1): 152–154. doi:10.4319/lo.1974.19.1.0152.
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