In histology and microscopy, Congo red is used for staining in amyloidosis, and for the cell walls of plants and fungi, and for the outer membrane of Gram-negative bacteria. Apple-green birefringence of Congo red stained preparations under polarized light is indicative of the presence of amyloid fibrils.
What is Congo red amyloid?
Congo red, despite having lower sensitivity, is the standard agent used to identify amyloid in tissues. While the apple-green birefringence seen under crossed polarized light is specific for amyloid material, staining with Congo red is technically difficult resulting in inconsistent staining.
What color is amyloid?
Amyloid appears yellow and blue, even though polarizer and analyzer are accurately crossed. Similar findings are common in everyday microscopy.
What does Congo red detect?
Staining with Congo Red dye (CR) is one of the major methods used to detect the amyloid structure of protein aggregates.
Is Congo red toxic to humans?
We determined that Congo Red is highly toxic to C.dubia since it inhibits survival and fertility in concentrations exceeding 3 mg L– 1. Our results show that this dye produces negative effects at very low concentrations.
Is Congo red azo dye?
Congo red is one of the best known and used azo dyes which has two azo bonds (-N=N-) chromophore in its molecular structure. … Above 97% were obtained when 2 g mycelia were incubated at pH 5, in presence of 200 mg/L of dye during 6 days at 28°C and under 120 to 150 rpm shaking speed.
Why is it called Congo red?
Congo red was introduced in Berlin in 1885 as the first of the economically lucrative direct textile dyes. … 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?
The Congo Red Capsule stain is a modification of the nigrosin negative stain you may have done previously. The bacteria take up the congo red dye and the background is stained then with acid fuchsin dye.
Is AA amyloidosis a terminal?
In AA amyloidosis, the deposited protein is serum amyloid A protein (SAA), an acute-phase protein which is normally soluble and whose plasma concentration is highest during inflammation. …
| AA amyloidosis | |
|---|---|
| Specialty | Rheumatology |
How does Congo red bind to amyloid?
CR binds to amyloid fibrils formed by both hydrophobic peptides (such as Aβ peptide) and hydrophilic peptides (such as GNNQQNY) and induces green-yellow birefringence under polarized light.
What is the principle of Congo red?
The Congo red staining principle is based on the formation of hydrogen bridge bonds with the carbohydrate component of the substrate. Congo red is an anionic dye and is capable of depositing itself in amyloid fibrils, which then exhibit a conspicuous dichroism under polarized light.
Is Congo red carcinogenic?
Congo Red is an azo dye, it is toxic to many organisms and is a suspected carcinogen and mutagen.
What is amyloid A?
Amyloid is an abnormal protein that is produced in your bone marrow and can be deposited in any tissue or organ. Amyloidosis frequently affects the heart, kidneys, liver, spleen, nervous system and digestive tract.
What is amyloid staining?
Amyloid Stain. Amyloidosis or aggregation and deposition of the amyloid protein (beta-pleated sheets) can be identified by using an amyloid stain on bone marrow biopsy specimens. Several different proteins can be converted to amyloid, including serum amyloid A protein and immunoglobulins.
Is there a blood test for amyloidosis?
Amyloidosis can be difficult to diagnose. There is no specific blood test and results of investigations vary greatly from patient to patient. The diagnosis of amyloidosis starts when a doctor becomes suspicious of the patient’s symptoms. A definitive diagnosis of amyloidosis can only be made through a biopsy.
Which Colour has disodium salt of Congo red?
Congo Red is the sodium salt of benzidinediazo-bis-1-naphthylamine-4-sulfonic acid; a diazo dye that is red in alkaline solution and blue in acid solution and used especially as an indicator and as a biological stain. … 5.4Related Compounds.
| Same Parent, Exact | 23 Records |
|---|---|
| Similar Compounds | 130 Records |
How do you make Congo red?
Congo Red is synthesised by coupling bis-diazotised benzidine with two molecules of napthionic acid. The blue dye so obtained is converted into its red disodium salt during its salting out with sodium chloride (Fig. 4.2).
Is used as a red paper dye?
Cochineal extract can dye paper a lovely red color.
Is Congo red a pH indicator?
“Congo red” is not the name of a famous African explorer, but a dye that dates to 1883. It was synthesized by P. Böttiger as a textile dye, but it subsequently became more important as a pH indicator. It colors aqueous solutions blue below pH 3.0 and becomes red above pH 5.0.
What is the pH range of Congo red?
pH 5.0 ChEBI: An indicator dye that is blue-violet at pH 3.0 and red at pH 5.0.
Is Congo red a basic or an acidic substance?
Congo red is an acid-base indicator dye. In free solution the colour and absorption characteristics of Congo red depend not only on the pH but are also governed by the nature of the solvent environment.
Why is Congo Red Blue?
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.
What does an Endospore stain tell you?
Welcome to Microbugz – Endospore Stain. The endospore stain is a differential stain used to visualize bacterial endospores. … By forming spores, bacteria can survive in hostile conditions. Spores are resistant to heat, dessication, chemicals, and radiation.
Why does nigrosin not penetrate the bacterial cell?
Why doesn’t nigrosin penetrate bacterial cells? The nigrosin is negatively charged, just like the cell membrane of the bacteria, which means there is a repulsion between the two, it is unable to penetrate.
What is the consequence of leaving a stain on too long?
. What are some consequences of leaving a stain on a bacterial smear too long (over-staining)? Consequences of over-staining are that the cell wall may be broken up or completely destroyed which would result in a loss of morphological characteristics of the bacterial cell.
What is the life expectancy of someone with amyloidosis?
On average, people with familial ATTR amyloidosis live for 7 to 12 years after they get their diagnosis, according to the Genetic and Rare Diseases Information Center. A study published in the journal Circulation found that people with wild-type ATTR amyloidosis live an average of about 4 years after diagnosis.
What are the symptoms of AA?
What are the signs and symptoms of AA amyloidosis?
- Swelling of the feet or legs.
- Excessive bubbles in the urine (foamy/frothy urine)
- Urinating less.
How long do you live with amyloidosis?
Amyloidosis has a poor prognosis, and the median survival without treatment is only 13 months. Cardiac involvement has the worst prognosis and results in death in about 6 months after onset of congestive heart failure. Only 5% of the patients with primary amyloidosis survive beyond 10 years.
Graduated from ENSAT (national agronomic school of Toulouse) in plant sciences in 2018, I pursued a CIFRE doctorate under contract with Sun’Agri and INRAE in Avignon between 2019 and 2022. My thesis aimed to study dynamic agrivoltaic systems, in my case in arboriculture. I love to write and share science related Stuff Here on my Website. I am currently continuing at Sun’Agri as an R&D engineer.