How is Congo red stain prepared?
Preparing the solutions for staining
Congo Red powder dye solution (for staining acc. to the Highman method): 1% solution of Congo Red powder dye: • Dissolve 0.5 g of Congo Red dye in 50 ml of distilled/demi water. Add 50 mL of 100% ethanol. Filter before use.
What type of stain is Congo red?
azo dye
It is an azo dye. Congo red is water-soluble, yielding a red colloidal solution; its solubility is greater in organic solvents.
What is Congo red stain test?
Staining with Congo Red dye (CR) is one of the major methods used to detect the amyloid structure of protein aggregates.
How does Congo red stain the cell wall?
Congo red was applied to growing yeast cells and regenerating protoplasts in order to study its effects on wall biogenesis and cell morphogenesis. In the presence of the dye, the whole yeast cells grew and divided to form chains of connected cells showing aberrant wall structures on both sides of the septum.
What is the purpose of Congo red dye?
Congo red was formerly used to dye cotton but has been superseded by dyes more resistant to light and to washing. It is still used in histology to stain tissues for microscopic examination, and to serve as an acid-base indicator, since it turns red in the presence of alkalies and blue when exposed to acids.
Why is it called Congo red?
It’s believed that the marketing people at AGFA (a Berlin-based company, remember) came up with the name Congo Red for their new sensational dye because, to Europeans in 1885, the Congo was seen as an exotic place, a land of mystery, and the name ‘Congo’ was currently on the tip of every tongue due to the world-famous …
Why is it called Congo red stain?
Conclusions: The Congo red stain was named “Congo” for marketing purposes by a German textile dyestuff company in 1885, reflecting geopolitical current events of that time.
Is Congo red a negative stain?
Congo red (1% aqueous) Solution is used as negative stain for bacteria and spirochaetes.