Dictionary » O » Orcein




A reddish brown amorphous dyestuff extracted from certain species of lichen (e.g. orchella weeds).


It is derived from orcinol extracted from lichens (e.g. Rocella tinctoria). The orcinol is converted to orcein by reacting with ammonia and air.

It forms the essential colouring matter of cudbear (a commercial powdered archil). It is used as a food dye forming dark brown crystals. It is also used as a stain in microscopy to visualize elastic fibers.

Word origin: from its related chemical product: orcinol.
Synonym: archil, orchil, lacmus, litmus, Citrus Red 2, C.I. Natural Red 28.
See also: orcinol, orcin.

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Plant chromosome staining

... you please tell me what is the best stain to observe plant chromosomes and their aberrations (specially in onion cells) ? Feulgen stain or Aceto orcein? And are there any other suitable stains? Thank you very much

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by Sue4
Sat Apr 20, 2013 8:10 am
Forum: Cell Biology
Topic: Plant chromosome staining
Replies: 0
Views: 1749

DNA from Drosophila salivary gland squash slides

I am trying unsuccessfully to isolate DNA from aceto orcein stained Drosophila salivary gland squashes that were fixed in acetic acid and a coverslip mounted with Coverbond (toluene soluble). They are old slides (about 30 years). I have soaked in toluene, ...

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by davidallenjohnson
Wed Nov 15, 2006 7:12 am
Forum: Molecular Biology
Topic: DNA from Drosophila salivary gland squash slides
Replies: 0
Views: 1387

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